OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 1

 FOREWORD INTRODUCITON

 LINEAR ALKYLBENZENE SULFONATE (LAS)

1322-98-1 Decylbenzene sulfonic acid, sodium salt 

 25155-30-0 Dodecylbenzene sulfonic acid, sodium salt 

 26248-24-8 Tridecylbenzene sulfonic acid, sodium salt 

 27636-75-5 Undecylbenzene sulfonic acid, sodium salt 

68081-81-2 C10-16 Monoalkylbenzene sulfonic acid, sodium salt 

68411-30-3 C10-13 Alkylbenzene sulfonic acid, sodium salt 

69669-44-9 C10-14 Alkyl deriv benzene sulfonic acid, sodium salt 

85117-50-6 C10-14 Monoalkylbenzene sulfonic acid, sodium salt 

90194-45-9 C10-13 Alkyl deriv benzene sulfonic acid, sodium salt 

127184-52-5 4-C 10-13-sec Alkyl deriv benzene sulfonic acid, sodium 

 salt 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 2

SIDS INITIAL ASSESSMENT REPORT 

For 

20th SIAM 

Paris, France, 19-21 April, 2005 

1. Chemical Name: Linear Alkylbenzene Sulfonate (LAS) 

2. CAS Numbers: 1322-98-1 Decylbenzene sulfonic acid, sodium salt 

25155-30-0 Dodecylbenzene sulfonic acid, sodium salt 

26248-24-8 Tridecylbenzene sulfonic acid, sodium salt 

27636-75-5 Undecylbenzene sulfonic acid, sodium salt 

68081-81-2 C10-16 Monoalkylbenzene sulfonic acid, sodium salt 

68411-30-3 C10-13 Alkylbenzene sulfonic acid, sodium salt 

69669-44-9 C10-14 Alkyl deriv benzene sulfonic acid, sodium salt 

85117-50-6 C10-14 Monoalkylbenzene sulfonic acid, sodium salt 

90194-45-9 C10-13 Alkyl deriv benzene sulfonic acid, sodium salt 

127184-52-5 4-C10-13-sec Alkyl deriv benzene sulfonic acid, sodium 

 salt 

3. Sponsor Country: United States 

National SIDS Contact Point in Sponsor Country: 

Oscar Hernandez, Director 

U.S. Environmental Protection Agency 

Risk Assessment Division (7403 M) 

1200 Pennsylvania Avenue, NW 

Washington DC 20460 

Phone: (202) 564-7461 

4. Shared Partnership with: Industry Coalition for the SIDS Assessment of LAS 

5. Roles/Responsibilities of the 

Partners: 

Industry was the main preparer; U.S. EPA was the main reviewer. It 

should be noted, however, that U.S. EPA did not review the exposure 

modelling that appears in Annex 1 and cannot make any conclusions 

regarding the exposure results of this modelling exercise. 

• Name of industry sponsor 

/consortium 

Industry Coalition for the SIDS Assessment of LAS 

• Process used Consortium member companies contributed in-house studies of 

physical-chemical properties, environmental fate and transport, 

ecotoxicity, and test organism toxicity for the chemicals and mixtures 

in the category. To supplement the industry data, literature searches 

were conducted employing a strategy utilizing databases available 

from the U.S. Chemical Information Systems and the European 

International Uniform Chemical Information Database (IUCLID) and 

Institute for Systems, Informatics And Safety (ISIS) Environmental 

Chemicals Data Information Network (ECDIN) databases. These 

databases include: 

Registry of Toxic Effects of Chemical Substances (RTECS) 

Hazardous Substances Database (HSDB) 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 3

Aquatic Toxicity Information Retrieval (AQUIRE) 

Toxic Substances Control Act Test Submissions (TSCATS) 

Integrated Risk Information System (IRIS) 

The Environmental Teratology Information Center (ETIC) 

The Developmental and Reproductive Toxicology Database (DART) 

The Catalog of Teratogenic Agents (CTA) 

ENVIROFATE, DATALOG, AQUIRE, PHYOTOX and 

TERRATOX 

Chemical Carcinogenesis Research Information (CCRIS) 

The Environmental Mutagen Information Center (EMIC) 

GENETOX 

Sax’s Dangerous Properties of Industrial Materials 

Agency for Toxic Substances and Disease Registry (ATSDR) 

Toxicological Profiles 

International Uniform Chemical Information Database (IUCLID) 

Environmental Chemical Data Information Network (ECDIN) 

TOXLINE 

www.chemfinder.com

standard scientific data compendia such as Verschueren (1996), CRC 

Handbook of Chemistry and Physics and The Merck Index. 

CAS Registry Numbers in dossier section 1.01 were used to match 

records available in each database. All reports identified were subject 

to a reliability check for determining adequacy in developing the 

Robust Summaries. U.S. EPA reviewed and edited drafts to come to 

consensus. 

6. Sponsorship History 

• How was the chemical or 

category brought into the 

HPV Chemicals Programme ? 

The industry coalition agreed to sponsor LAS in the SIDS-ICCA 

program, with the U.S. EPA being the country sponsor. 

7. Review Process Prior to the 

SIAM: 

Prepared by Industry. Reviewed by U.S. EPA to come to a consensus 

document. Human health portion of SIAP accepted at SIAM 17, 

Arona, Italy, November 2003. Environmental portion of SIAP 

accepted at SIAM 20, Paris, France, April 2005. U.S. EPA did not 

evaluate the exposure annex and therefore, can make no conclusions 

regarding these values. 

8. Quality Check Process: Industry coalition members developed the documents, which were 

then reviewed by outside third parties. 

9. Date of Submission: Revised document submitted August 15, 2005. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 4

CH3(CH2)

5CH(CH2)4CH3

S03

 - Na+

SIDS INITIAL ASSESSMENT PROFILE

CAS Nos. 1322-98-1 Decylbenzene sulfonic acid, sodium salt 

25155-30-0 Dodecylbenzene sulfonic acid, sodium salt 

26248-24-8 Tridecylbenzene sulfonic acid, sodium salt 

27636-75-5 Undecylbenzene sulfonic acid, sodium salt 

68081-81-2 C10-16 Monoalkylbenzene sulfonic acid, sodium salt

68411-30-3 C10-13 Alkylbenzene sulfonic acid, sodium salt 

69669-44-9 C10-14 Alkyl deriv benzene sulfonic acid, sodium 

 salt 

85117-50-6 C10-14 Monoalkylbenzene sulfonic acid, sodium salt

90194-45-9 C10-13 Alkyl deriv benzene sulfonic acid, sodium 

 salt 

127184-52-5 4-C10-13-sec Alkyl deriv. benzene sulfonic acid, 

 sodium salt 

Category Name Linear Alkylbenzene Sulfonate (LAS) 

Structural Formula 

This structure of a C12-LAS is representative of the category. 

SUMMARY CONCLUSIONS OF THE SIAR 

Category Identification/ Justification 

The LAS molecule contains an aromatic ring sulfonated at the para position and attached to a linear alkyl chain at 

any position except the terminal carbons. The alkyl carbon chain typically has 10 to 14 carbon atoms and the 

linearity of the alkyl chains ranges from 87 to 98%. While commercial LAS consists of more than 20 individual 

components, the ratio of the various homologs and isomers, representing different alkyl chain lengths and 

aromatic ring positions along the linear alkyl chain, is relatively constant in currently produced products, with the 

weighted average carbon number of the alkyl chain based on production volume per region between 11.7-11.8. 

LAS are supported as a category because of the close consistency of the mixtures, their commercial uses, fate, and 

health and environmental effects. LAS is the primary cleaning agent used in many laundry detergents and 

cleaners at concentrations up to 25 percent in consumer products, and up to 30 percent in commercial products, 

with the exception of one reported product at 45% percent in concentrated solid form that is mechanically 

dispensed into diluted solution for dishwashing. 

Human Health 

Substantial data exist for mammalian toxicity. The available data indicate that LAS exhibits slight acute toxicity. 

Oral LD50 values for rats range from 1,080 to 1,980 mg/kg bw. Oral LD50 values for mice are 2,160 and 2,250 

mg/kg bw for males and females, respectively. The rat dermal LD50 value was greater than 2,000 mg/kg bw. The 

oral and dermal acute toxicity data for LAS generally indicate low hazard potential when all studies are 

considered together. Acute inhalation toxicity data indicate that LAS is moderately toxic, with mortality 

occurring at respirable particle concentrations of 310 mg/m3

 (MMAD = 2.5 microns). 

In a series of studies on rabbits, LAS was not irritating to the skin or eyes at low concentrations (0.5-2.5%), 

moderately irritating at 5%, and more severely irritating at higher (about 50%) concentrations. In studies that 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 5

included rinsing, eye irritation effects diminished with rinsing after 30 seconds of exposure and were slight with 

rinsing after 4 seconds of exposure. In a low volume eye test (LVET) using a 35% LAS solution, rabbits 

experienced moderate irritation that was completely reversible by day 35. (Note that the maximum concentration 

of LAS is 25 percent in consumer products and normally less than 30 percent in commercial products.) 

Accidental eye exposure in 231 manufacturing employee incidents and 284 consumer incidents established that 

eye irritation effects of exposure during manufacturing and use of products containing LAS and other surfactants 

are moderate, transient and reversible. 

In 15 repeated dose studies with rats, mice, and monkeys exposed to LAS via oral and dermal routes, LOAELs 

ranged from 115 to 750 mg/kg bw/day. The corresponding NOAELs ranged from 40 to 250 mg/kg bw/day. 

Effects commonly observed included suppressed body weight gain, diarrhea, increases in relative liver weight, 

differences in enzymatic and serum-biochemical parameters, and mild degeneration and desquamation of the 

tubular epithelium in the kidneys. 

In four well designed in vitro bacterial (Salmonella) mutagenicity studies, LAS shows no evidence of 

mutagenicity either with or without S9 metabolic activation. LAS showed no evidence of causing increased cell 

transformation in an in vitro cell transformation assay. In in vivo studies, no significant differences in 

chromosome aberrations were seen when mice were given either oral doses up to 800 mg/kg bw/day or dietary 

doses up to 1170 mg/kg bw/day. In a mouse micronucleus study, LAS did not induce a clastogenic effect. Rats 

given dietary doses up to 450 mg/kg bw/day also showed no significant differences in chromosome aberrations. 

Collectively, these data support that LAS is not genotoxic. 

The highest dose tested in four carcinogenicity studies with rats was 300 mg/kg bw/day. In the most documented 

study, rats were administered up to 250 mg LAS/kg body weight/day in the diet for two years. Results of this 

study indicate no gross or histopathological evidence of a carcinogenic effect. No evidence of tumorigenesis was 

observed in any of the carcinogenicity studies. While the quality and focus of the studies precludes a definitive 

assessment, the results of the genetic toxicology and rodent bioassay studies collectively provide strong weightof-evidence support that LAS is not genotoxic and is not a rodent carcinogen. 

 

Similarly, no evidence of reproductive or fertility effects was observed in any of the three available reproductive 

toxicity studies in which rats were given dietary doses over three to four generations. NOAELs from these 

reproductive studies ranged from 70 to 350 mg/kg bw/day, which were the highest doses tested. In 17 

developmental toxicity studies, effects such as embryo death or deformities, and litter loss were most often 

observed only at maternally toxic doses and were associated with the irritation effects of LAS on skin or the 

gastrointestinal tract. No decreases in litter size, no changes in litter parameters, no malformations or significant 

differences in skeletal defects were observed at oral doses up to 780 mg/kg bw/day in rats and at dermal doses of 

500 mg/kg bw/day in mice and 90 mg/kg bw/day in rabbits. 

All of the studies included in the dossier are considered reliable, but all with limitations. The results are 

consistent with each other and these data are used in a weight-of-evidence approach. Based on these 

considerations, the highest NOAEL value below the lowest LOAEL from all of the mammalian toxicity studies is 

the most appropriate. Therefore, the NOAEL is 85 mg/kg bw/day. This value comes from a rat drinking water, 

9-month repeated dose toxicity study. The lowest LOAEL (115 mg/kg/day) was associated with increased 

weight of the cecum and slight degeneration of the renal tubules. 

Environment 

Pure LAS is a solid at ambient temperatures with a melting point of 198.5°C. The boiling point for LAS could 

not be determined experimentally due to decomposition beginning at 444°C. LAS has a low vapor pressure 

(calculated as 3-5 x 10-13 Pa). LAS is water soluble, with a critical micelle concentration (CMC) value of 0.1 

g/L and forms a clear solution in water at concentrations up to 250 g/L. Although it is impossible to accurately 

measure an octanol-water partition coefficient for surface-active agents like LAS, an octanol-water partition 

coefficient of log 3.32 has been calculated for C11.6 LAS. Kd values for LAS in activated sludge and sediment 

increased with increasing alkyl chain length of LAS homologues with Kd values for C12 LAS of 3210 L/kg in 

activated sludge and 330 L/kg in river sediment. In activated sludge, sorption and desorption equilibria for LAS 

were achieved very rapidly, and comparison of the extent of sorption and biodegradation shows that the 

absorbed fraction as well as the soluble fraction of LAS is available for biodegradation. Based on Fugacity III 

modeling results using the most relevant input parameters, more than 99 percent of the residual (nonbiodegraded) fraction of LAS distributes to the soil. LAS does not undergo significant degradation by abiotic 

mechanisms under environmentally relevant conditions as photolyzable and hydrolyzable groups are absent 

from the chemical structure. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 6

An extensive database of studies demonstrates rapid and complete (ultimate) biodegradation of LAS in many of 

the available aerobic biodegradation tests, including soil and the aqueous environment. In several tests, LAS has 

been shown to be readily biodegradable, and has passed the 10-day biodegradation window in mineralization 

tests for most ready tests. LAS is removed in biological wastewater treatment at percentages ranging from 77-

82% for trickling filters up to 99%+ for activated sludge. The biodegradation kinetics of the longer alkyl chain 

lengths are generally faster, and their sorption coefficients larger. The primary degradation intermediates are 

sulfophenyl carboxylates (SPCs), which further degrade to CO2, SO4

2-, and water. LAS does not generally 

degrade under anaerobic conditions. The measured bioconcentration factors of pure homologues and isomers 

decrease with decreasing average alkyl chain lengths (from almost 1000 for 2-phenyl-C13 LAS to 2 for 6-phenylC10 LAS), all with rapid clearance. The calculated BCF for currently produced C11.6 LAS is 87 and was 22 for 

filtered Mississippi River water (average alkyl chain length of surface water fingerprint = C10.8). 

Ecotoxicity data are extensively available for LAS, with several comprehensive reviews having been completed. 

The lowest reliable acute LC50/EC50/ErC50 values based on a review of the aquatic toxicity data on commercially 

representative LAS (C11.6-C11.8) were 1.67, 1.62 and 29.0 mg/L for fish, Daphnia magna, and algae, respectively. 

Acute toxicity is greater for individual LAS homologues with longer alkyl chain lengths. LAS biodegradation 

intermediates are significantly less toxic than the parent LAS with L/EC50 values >1000 mg/L for fish and D. 

magna. Chronic freshwater toxicity studies following guideline exposures (28-30 days for fish, 21 days for 

invertebrates and 3-4 days for algae provided the following NOEC values: fish NOEC = 1 mg/L (two studies, 

two species); Daphnia, NOEC = 1.18-3.25 mg/L (six values, two studies, one with 5 diets); algae, NOEC = 0.4-

18 mg/L (four studies, two species). In addition all of the available, reliable chronic single species aquatic 

toxicity data on LAS have been evaluated, including three freshwater species in which multiple studies were 

reported and nine freshwater species for which single studies were reported. Single NOEC values and geometric 

mean NOEC values (calculated for species with multiple results) were normalized to C11.6 LAS. These NOEC 

values range from 0.25 to 6.1 mg/L for freshwater species, including fish, invertebrates, algae and higher plants. 

Geometric mean NOEC values for marine species ranged from 0.025 to 5.0 mg/L. Based on the model 

ecosystem studies, a NOEC of 0.27 mg/L (0.37 if normalized to C11.6 LAS) was determined for the freshwater 

ecosystem. This value is based on model stream ecosystem studies of over 250 species, and is consistent with 

the single species chronic freshwater data. 

NOEC values for sediment exposures were greater than or equal to 81 mg/kg dry matter based on studies in four 

species, including GLP studies in L. variegates (survival, reproduction and growth over 28 days) and C. elegans

(egg production, 3 days). Field studies indicate no adverse effects of LAS in sludge-amended soil from LAS 

levels of 15 mg/kg dry matter in the soil (9 microbial functions/processes and abundance/diversity of 

microarthropods and earthworms, short-term and 4 years) or 31,300 mg/kg dry matter in sludge (function of 

microbial community, short-term and 1 year). 

In laboratory studies in which young trees are exposed to artificial sea spray, LAS concentrations of 10 mg/L 

lead to increased foliar penetration of NaCl, a hypothesized mechanism of defoliation. 

A health and environmental risk assessment is available (heraproject.com). 

Exposure 

Current LAS production is approximately 390,000 metric tons in the North America, 400,000 metric tonnes in 

Europe, and 85,000 metric tonnes in Japan. Global production was 2.6 million metric tonnes in 1995. In the 

production phase, manufacturing processes have been designed to maximize production yield and minimize 

potential releases. Worker exposure is possible during the detergent formulation stage by inhalation of powders 

or dermal contact of powders and liquids. Good manufacturing design practices (e.g., enclosed production in 

agglomeration processes, exhaust ventilation, dust collection) and personal protective equipment (e.g., protective 

clothing, eyewear, and gloves) in place at facilities that manufacture liquid and dry (granular/powder) materials 

are anticipated to mitigate worker exposure to LAS. Any LAS that is not incorporated into a product is captured 

by dust-handling equipment for recycling back into the production process. A limited amount of LAS in 

aqueous solution may be released as a dilute solution from washing and rinsing operations in the manufacturing 

process and is discharged to wastewater treatment. Incidental quantities of the dry (granular/powder) product 

(e.g., from floor sweepings) may be disposed in landfills. 

Labeling of consumer products containing LAS and other surfactants include warnings of the potential for eye 

irritation and first aid instructions to rinse with water. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 7

Data suggest that inhalation of LAS products during use will be low. Spray products containing LAS are 

designed to produce the large particle sizes needed for efficient delivery of the spray to the surface being 

cleaned. In laboratory simulations with six spray nozzles representing those used in spray cleaning products, 

less than 0.1% of the total volume sprayed consists of respirable particles (particles under 10 microns in 

diameter) and air concentrations in the breathing zone are in the 0.13-0.72 mg/m3

 range. Inhalation of detergent 

dusts during washing processes, modeled by HERA (2004), was 10-fold lower than inhalation of aerosols from 

cleaning product sprays. This estimate is based on a published study reporting an average of 0.27 μg dust per 

cup of product used for machine laundering. This is a conservative (protective) estimate as exposure from 

modern compact/granular detergent formulations produced in agglomeration processes, which produce larger 

particle sizes, would be expected to be much less. Based on these data, it is expected that exposures to 

respirable particles from inhalation are low. 

Results of extensive environmental monitoring evaluations in the United States indicate that measured surface 

water concentrations were generally below 50 μg/L for river water samples collected under low dilution (worst 

case) conditions below treatment plant mixing zones. Values in the 2800 km reach of the Mississippi River 

from Minneapolis to New Orleans range from non-detect (<0.1 μg/L) to 28 μg/L (362 samples). LAS river 

water concentrations similar to those in the US were observed in monitoring studies conducted in Europe and 

Japan. 

Measured LAS concentrations in river sediments were generally less than 1-2 mg/kg dry weight. Mississippi 

River sediments were <1 mg/kg dry matter with one exception. LAS levels in sediments of the receiving waters 

of the Tiber River (Italy) were 1.8 mg/kg dry matter. Higher LAS concentrations have been observed near 

untreated or poorly treated wastewater discharges, e.g. LAS in sediments of a small river (Rapid Creek, USA) 

below a trickling filter treatment plant averaged 190 mg/kg just below the outfall, 11.2 mg/kg less than 5 miles 

downstream and 5.3 mg/kg greater than 5 miles downstream

RECOMMENDATION AND RATIONALE FOR THE RECOMMENDATION AND 

NATURE OF FURTHER WORK RECOMMENDED 

Human Health: The chemicals in the LAS category are currently of low priority for further work because of their 

low hazard potential except for skin and eye irritation and acute inhalation. Based on data presented by the 

Sponsor Country, exposure to respirable particles is anticipated to be low. Other countries may desire to 

investigate any exposure scenarios that were not presented by the Sponsor Country. 

Environment: The chemicals in the LAS category possess properties indicating a hazard for the environment 

(fish, invertebrates and algae). However, they are of low priority for further work due to ready and/or rapid 

biodegradation and limited potential for bioaccumulation. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 8

CH3(CH2)

5CH(CH2)4CH3

S03

 - Na+

SIDS Initial Assessment Report 

1 IDENTITY 

1.1 Identification of the Substance Category 

CAS Number: 1322-98-1 Decylbenzene sulfonic acid, sodium salt 

25155-30-0 Dodecylbenzene sulfonic acid, sodium salt 

26248-24-8 Tridecylbenzene sulfonic acid, sodium salt 

27636-75-5 Undecylbenzene sulfonic acid, sodium salt 

68081-81-2 C10-16 Monoalkylbenzene sulfonic acid, sodium salt 

68411-30-3 C10-13 Alkylbenzene sulfonic acid, sodium salt 

69669-44-9 C10-14 Alkyl deriv benzene sulfonic acid, sodium salt 

85117-50-6 C10-14 Monoalkylbenzene sulfonic acid, sodium salt 

90194-45-9 C10-13 Alkyl deriv benzene sulfonic acid, sodium salt 

127184-52-5 4-C10-13-sec Alkyl deriv benzene sulfonic acid, sodium 

 salt 

Chemical Name: Linear Alkylbenzene Sulfonate (LAS) 

Description LAS is the primary cleaning agent used in many laundry detergents 

and cleaners at concentrations up to 25 percent in consumer products, 

somewhat higher in industrial/commercial products. The LAS 

molecule contains an aromatic ring sulfonated at the para position 

and attached to a linear alkyl chain at any position except the terminal 

carbons (Valtorta et al., 2000). The linear alkyl carbon chain 

typically has 10 to 14 carbon atoms, with the approximate mole ratio 

varying somewhat regionally with weighted averages of 11.7-11.8. 

The alkyl chains are >95% linear. The structure of C12-LAS, 

representative of the category, is shown in the figure. While 

commercial LAS consists of more than 20 individual components, the 

ratio of the various homologues and isomers, representing different 

alkyl chain lengths and aromatic ring positions along the linear alkyl 

chain, is relatively constant across the various detergent and cleaning 

applications. Because of the close consistency of the mixtures, their 

commercial uses, fate and effects, LAS is discussed as a category 

rather than as individual CAS numbers in this assessment. 

Molecular Weight Range depending on alkyl chain length from 338 (C11.3) to 356 (C12.6) 

The approximate weight percentage of the alkyl chain varies 

somewhat regionally as shown below. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 9

Region <C10 C10 C11 C12 C13 C14 >C14

Range of 

Averages 

Weighted 

Average* 

Canada 

68081-81-2 

≤1 <16 19-39 20-50 5-27 <3 <1 11.8 11.8 

Europe 

25155-30-0 

68081-81-2 

68411-30-3 

85117-50-6 

90194-45-9 

127184-52-5 

≤1 8-20 19-39 20-50 5-27 <1-3 <1 11.6-11.8 11.7 

Japan 

68081-81-2 

68411-30-3 

69669-44-9 

≤1 7-16 19-39 20-50 5-27 <1-3 <1 11.7-11.8 11.8 

United States 

1322-98-1** 

25155-30-0 

26248-24-8** 

27636-75-5** 

68081-81-2 

69669-44-9 

85117-50-6 

90194-45-9 

<2 1-25 7-50 20-50 5-45 <1-10 <1 11.3-12.6 11.7 

* Weighted by production volume for each region. 

**Manufacture of LAS under these CAS numbers has recently been discontinued. 

As shown in the table, all the LAS category members (CAS numbers) have the alkyl chain 

distributions for the LAS category. All of the data in this assessment, except for data identified as 

such, is on LAS category materials having the alkyl chain distribution shown in the table. 

1.2 Production/Purity/Impurities 

LAS is manufactured from linear alkylbenzene (LAB) in self-contained, enclosed systems (see 

Annex, Format A, Section VI(1), for more information). LAB is produced by reacting paraffins 

with benzene and a catalyst and isolating the LAB by distillation. The LAB is then sulfonated, 

which in turn is then neutralized to sodium salts of LAS. 

Commercial LAS is exclusively manufactured as mixtures of C10 to C13 or C14 alkyl chain 

homologues, having average alkyl chain lengths ranging from C11.3 to C12.6, with the 

predominant materials having average alkyl chain lengths ranging from C11.7 to C11.8 (Table 

above). Each alkyl chain homologue consists of a mixture of all the possible sulfophenyl isomers 

except for the 1-phenyl isomer, which is not found in the commercial material. The catalyst used to 

make the LAB determines the distribution of the phenyl isomers in commercial LAS with the 

proportion of the 2-phenyl isomers ranging from 18 to 28% (Valtorta et al., 2000). Consequently, 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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commercial LAS consists of a mixture of 20 or more compounds, the 2-phenyl to 5-phenyl isomers 

of the C10 homologue, the 2-phenyl to 6-phenyl isomers of the C11 and C12 homologues and the 2-

phenyl to 7 phenyl isomers of the C13 homologue, etc. 

The commercial material is >95% pure LAS. Some methyl-substituted (i.e., iso-branched) LAS 

may be present in the mixtures (Nielsen et al. 1997). The amount of the iso-LAS component is 

small (1-6%) and was shown not to limit biodegradation relative to pure linear component (Nielsen 

et al. 1997; Cavalli et al. 1996). Non-linear components such as dialkyltetralin sulfonates (DATS) 

can be present at levels of less than 1 to 8% depending on the manufacturing process (Nielsen et al. 

1997). DATS, like iso-LAS, have been shown to be biodegradable (Nielsen et al. 1997). 

Improvements in processing techniques in the U.S., Europe, and Japan incorporated to increase 

LAS yields also reduce the amount of DATS present. 

While historically LAS has ranged from 87-98% pure, recent market information (LAS SIDS 

Consortium, unpublished, 2005) indicates that less than 5% of the global LAS production contains 

high levels of DATS. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 11

1.3 Physico-Chemical properties 

Table 1 Summary of physico-chemical properties 

Property Value Method Reference (Reliability) 

Physical state Solid Dossier 1.1B 

Melting point 

198.5oC 

274oC 

279oC 

284oC 

290oC 

Experimental (C12.0) 

Calculated as C10* 

Calculated as C11* 

Calculated as C12* 

Calculated as C13* 

Dossier 2.1a (2) 

Dossier 2.1b (2) 

Dossier 2.1c (2) 

Dossier 2.1d (2) 

Dossier 2.1e (2) 

Boiling point 

Decomposition onset 

at 444oC 

630oC 

642oC 

654oC 

665oC 

Experimental (C12.0) 

Calculated as C10* 

Calculated as C11* 

Calculated as C12* 

Calculated as C13* 

Dossier 2.2a (2) 

Dossier 2.2b (2) 

Dossier 2.2c (2) 

Dossier 2.2d (2) 

Dossier 2.2e (2) 

Relative density 1.06 g/cm3 Experimental (C11.6) Dossier 2.3a (4) 

Bulk density 450-550 kg/m3 Experimental (C11.6, 

C12.0) Dossier 2.3b,c (4) 

Vapor pressure (at 25oC) 

3 x 10-13 Pa 

2.88 x 10-12 Pa 

1.22 x 10-12 Pa 

5.13 x 10-13 Pa 

2.16 x 10-13 Pa 

Calculated as C12

[using all phenyl 

position isomers]

Calculated as C10* 

Calculated as C11* 

Calculated as C12* 

Calculated as C13* 

Dossier 2.4a (4) 

Dossier 2.4b (2) 

Dossier 2.4c (2) 

Dossier 2.4d (2) 

Dossier 2.4e (2) 

Partition coefficient noctanol/water (log value) 

3.32 

1.94 

2.43 

2.92 

3.42 

Calculated as C11.6

[using all phenyl 

position isomers]]

Calculated as C10* 

Calculated as C11* 

Calculated as C12* 

Calculated as C13* 

Dossier 2.5a (2) 

Dossier 2.5b (2) 

Dossier 2.5c (2) 

Dossier 2.5d (2) 

Dossier 2.5e (2) 

Critical micelle 

concentration 0.1 g/L Experimental (C12) Dossier 2.6Aa (2) 

Water solubility 250 g/L Experimental (C11.6) Dossier 2.6Ab (2) 

pH 10.0 ± 1 1% solution (C12.0) Dossier 2.6Ba (4) 

pKa <1 

Based on structural 

analogue (benzene 

sulfonic acid) 

Dossier 2.6Bb (4) 

Henry’s law constant 6.35 x 10-3 Pa 

m3

/mole Calculated as C12 Dossier 2.13A (2) 

* Structure modelled is the pure homologue, 2-phenyl isomer, not the commercial material. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 12

Table 1 summarizes the representative physico-chemical properties of LAS. Pure LAS is a solid at 

ambient temperatures. The melting point for LAS has been experimentally determined. EPI Suite 

calculations (dossier 2.1b-e), which are reliable for predicting trends, indicate that the melting point 

and boiling point increase with increasing alkyl chain length as expected. The boiling point for 

LAS could not be determined experimentally due to decomposition. EPI Suite calculations indicate 

that vapour pressure and log Kow also increases with increasing alkyl chain length. Since 

surfactants such as LAS preferentially partition to the octanol-water interface, it is impossible to 

accurately measure a log Kow. However, Roberts (1991) found that QSARS developed to calculate 

log Kow have shown a high correlation to measured acute toxicity data for multiple species and 

multiple surfactants, including LAS. The most reliable calculated value for C11.6 LAS (log Kow = 

3.32) takes into account the various phenyl position isomers of LAS. LAS is water soluble, with a 

critical micelle concentration (CMC) value of 0.1 g/L and forms a clear solution in water at 

concentrations up to 250 g/L. 

1.4 Category Justification 

The LAS molecule contains an aromatic ring sulfonated at the para position and attached to a linear 

alkyl chain at any position except the terminal carbons. The alkyl carbon chain typically has 10 to 

14 carbon atoms and the linearity of the alkyl chains ranges from 87 to 98%. While commercial 

LAS consists of more than 20 individual components, the ratio of the various homologues and 

isomers, representing different alkyl chain lengths and aromatic ring positions along the linear alkyl 

chain, is relatively constant in currently produced products, with the weighted average carbon 

number of the alkyl chain based on production volume per region between 11.7-11.8. LAS is 

supported as a category because of the close consistency of the mixtures, their commercial uses, 

fate, and health and environmental effects. LAS is the primary cleaning agent used in many laundry 

detergents and cleaners at concentrations up to 25 percent in consumer products, and up to 30 

percent in commercial products, with the exception of one reported product at 45% percent in 

concentrated solid form that is mechanically dispensed into diluted solution for dishwashing. 

2 GENERAL INFORMATION ON EXPOSURE 

2.1 Production Volumes and Use Pattern 

LAS is manufactured from linear alkylbenzene (LAB) in self-contained, enclosed systems (see 

Annex 1 for more information). LAB is produced by reacting paraffins with benzene and a catalyst 

and isolating the LAB by distillation. The LAB is then sulfonated, which in turn is then neutralized 

to sodium salts of LAS. 

Data on LAS production and consumption volumes, uses, releases and potential exposures were 

collected from published sources and surveys of member companies of the Industry Coalition for 

the SIDS Assessment of LAS, representing about 75% of the North American production of LAS. 

Approximately 390,000 metric tons of LAS were consumed in North America (United States and 

Canada combined) in 2000 (Colin A. Houston, 2002). Production in Europe in 2000 was 

approximately 400,000 metric tons (as reported in HERA 2004). Production in Japan in 2001, 

where all of the LAS producers are members of the consortium, was approximately 85,000 metric 

tons based on the results of the Coalition survey. Global production was 2.6 million metric tons in 

1995, the most recent data available (EU Risk Assessment Report for LAB, 1997). 
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Based on the results of the survey of consortium members (LAS SIDS Coalition Survey 2002), 

about 78-97% of the LAS consumption worldwide is in liquid and powder consumer and industrial 

laundry and fine fabric detergents. Another 2-10% of the LAS produced is used in consumer and 

industrial dishwashing liquids, with the remainder used in other consumer and industrial cleaners. 

Following use, the predominant disposal route for these products is via the wastewater. Tables 2 

and 3 show the percentage of LAS that occurs in various types of consumer and industrial detergent 

products. 

Table 2. Percentage of LAS in Different Types of Consumer Products1

Range of Percent Composition that is LAS Consumer Product Type 

North America Europe Japan 

Laundry Detergents 

Powders 

Liquids 

Tablets 

5-25% 

1-25% 

5-25% 

5-25% 

5-10% 

10-25% 

5-25% 

5-25% 

5-25% 

Liquid Fine Fabric Detergents - - 1-5% 

Bleaches - - 0.1-0.5% 

Pre-Washes - - 5-10% 

Fabric Conditioners (sheets) 0.1-0.5% - - 

Dishwashing Detergents 

(liquids) 5-25% 10-25% 1-5% 

General Cleaners (dilutable) 1-5% 1-5% - 

Hard Surface Cleaners 1-5% 0.1-0.5% 0.5-10% 

Other Cleaners - - 0.1-0.5% 

Face & Hand Soaps (bar) 1-5% - - 

1

 LAS SIDS Coalition Survey 2002 

Table 3. Percentage of LAS in Different Types of Institutional and Industrial Products1

Range of Percent Composition that is LAS Industrial Product Type 

North America Europe Japan 

Laundry Detergents 

Powders 

Liquids 

5-25% 

- 

5-10% 

10-25% 

5-10% 

- 

Pre-Washes - 10-25% - 

Dishwashing Detergents (liquids) 5-10% 25-30% 5-30% 

General Cleaners 

Dilutable 

Spray 

1-5% 

1-5% 

- 

- 

- 

- 

Hard Surface Cleaners - - 1-10% 

Disinfectants (liquids) 5-10% - - 

Other Uses 25-30%2 10-25% 10-25% 

1

 LAS SIDS Coalition Survey 2002 

2 The only exception is a product containing 45% LAS that is a concentrated solid mechanically dispensed into diluted 

solution for dishwashing. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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2.2 Environmental Exposure and Fate 

2.2.1 Sources of Environmental Exposure 

Based on the results of the survey of members of the Coalition (LAS SIDS Coalition Survey 2002; 

year 2000 data), there is a potential for releases to the environment from manufacturing and 

formulation, although processes have been designed to maximize production yield and minimize 

potential releases. In the US, LAS that is not incorporated into a product is captured by dusthandling equipment for recycling back into the production process. A limited amount of LAS in 

aqueous solution may be released as a dilute solution from washing and rinsing operations in the 

manufacturing process and discharged to wastewater treatment. Incidental quantities of the dry 

(granular/powder) product (e.g., from floor sweepings) may be disposed in landfills. 

Environmental releases from down-the-drain discharges following product use could lead to 

potential ecological exposures in surface waters and possibly in agricultural soils. Products 

containing LAS disposed of down-the-drain are transported to wastewater treatment plants or 

discharged to the environment. LAS not biodegraded in wastewater treatment will be discharged in 

effluent or in the biosolids (sludge) produced by wastewater treatment. LAS in sludge may enter 

the environment from land application of sludge to agricultural soil or in leachate from landfills. 

Based on its temperature of decomposition, LAS is unlikely to enter the environment from 

incineration of sludge. 

2.2.2 Photodegradation 

LAS has low vapor pressure (3 x 10-13 Pa for C12 LAS) indicating significant amounts of LAS are 

unlikely to be present in the atmosphere for photodegradation. Data are available on the 

photodegradation of LAS in water but not for other environmental compartments. There is no 

evidence of LAS photodegradation in water under environmental conditions and the absence of 

photolyzable groups suggests that LAS is unlikely to undergo significant degradation by this 

mechanism. However, LAS photodegradation in water has been demonstrated in the presence of 

photoactivating materials (and typically high intensity light spectrum). Matsuura and Smith (1970) 

found >95% photolytic degradation after 20 minutes for aqueous LAS solutions exposed to a 1200-

watt mercury vapor lamp using ferric perchlorate as a sensitizer. Hidaka et al. (1985) found rapid 

(<1-2 hours) decomposition of the aromatic ring followed by slower oxidation of the aliphatic chain 

for LAS in aqueous TiO2 solutions under a xenon lamp. Hermann et al. (1997) found that the 

presence of humic substances delayed the mercury lamp photodegradation of LAS in aqueous 

solutions by factor of two or more. 

2.2.3 Stability in Water 

Cross and Dekker (1977) reported degradation of LAS by abiotic hydrolysis under extreme 

conditions (e.g., elevated temperatures, presence of inorganic acids) not likely to be encountered in 

the environment. Based on the results from extreme conditions and professional judgment, it is 

concluded that LAS does not degrade significantly by non-biological mechanisms. The reliability 

of this study could not be assigned because the original data were not available for review. 

However, the absence of readily hydrolysable groups in the chemical structure and the use pattern 

in shelf-stable liquid cleaning products supports this conclusion. 
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2.2.4 Stability in Soil 

Several measurements of LAS in sludge-amended soil from both laboratory and field studies have 

been reported. Figge and Schoberl (1989) conducted a laboratory study using 14C LAS (mixture not 

defined), and thus measuring ultimate biodegradation, showing LAS mineralization rates in soil 

corresponding to half lives (t0.5) of 13-26 days. Knaebel et al. (1990) observed more rapid 

mineralization (half lives of 1.1-3.7 days) of C13 LAS in 10 soil types. Ward and Larson (1989) 

observed similar rates of mineralization (half lives of 15.8 to 25.7 days) as Figge and Schoberl 

using pure C10 to C14 LAS homologues and two different soil types. In the most recent laboratory 

study, Elsgaard et al. (2001b) showed more than 73% primary biodegradation for nominal LAS 

concentrations of 8 to 62 mg/kg and a 15% depletion for nominal concentrations of 488 mg/kg after 

two weeks in soil spiked with aqueous LAS and LAS-spiked sewage sludge. 

Field investigations in the U.K. in which the annual sludge spreading averaged 6 ton/ha (Holt et 

al.,1989; Waters et al., 1989) demonstrated LAS removal (primary biodegradation) corresponding 

to half lives in the range of 7-22 days. At a landfilling operation in Spain in which very high levels 

of sludge were blended with soil (15% sludge, 85% soil), an LAS half live of 19.3 days was 

observed (de Ferrer et al., 1997). At sludge application rates within those currently recommended in 

Europe (equal or below 5 ton/ha/y), a field study estimated t0.5 values, due to primary 

biodegradation, in the range of 3-7 days (Küchler and Schnaak,1997). Mortensen et al. (2001) also 

reported data for degradation of LAS in sludge-amended soil under realistic field conditions. LAS 

was not taken up by plants and its degradation in soil increased by the presence of crop plants with 

concentration decreasing from 27 mg/kg (dry soil) to 0.7-1.4 mg/kg (dry soil) at harvesting time 

after 30 days (t0.5 <4 d). During degradation, the relative fractions of homologues C10, C11, and C12

decreased, while C13 increased. 

2.2.5 Transport between Environmental Compartments 

Games (1982; reliability not assignable) reported that Kd values for LAS increased with increasing 

alkyl chain length of LAS homologues. Kd values (L/kg) for activated sludge ranged from 220 

(C10 LAS), 1000 (C11 LAS), 3070 (C12 LAS) to 9330 (C13 LAS). Kd values for river sediment 

ranged from 41 (C10 LAS), 100 (C11 LAS), 330 (C12 LAS), 990 (C13 LAS) to 2950 (C14 LAS). 

Traina et al. (1996) also reported that log Koc values (L/kg) for LAS and dissolved humic 

substances increased with increasing alkyl chain length: 4.02 (C10 LAS), 4.83 (C12 LAS) and 5.49 

(C14 LAS). Based on the C11 and C12 LAS-activated sludge data, Feijtel et al. (1999) estimated 

the Kd value for commercially representative C11.6 LAS and activated sludge as 2512 L/kg. Very 

recently, Temmink and Klapwijk (2004) determined the sorption properties of LAS using activated 

sludge from a pilot-scale treatment plant. The Kd value (L/kg) for C12 LAS was 3210 L/kg, 

virtually identical to the value reported by Games (1982). Applying the same estimation procedures 

as used by Feijtel et al. (1999; reliability not assignable) results in a Kd value for C11.6 LAS and 

activated sludge of 2500 L/kg. Painter and Zabel (1988) estimated Kd values of between 6 and 300 

L/kg in water-river sediments and between 2 and 20 L/kg in water-soil, in both cases dependent on 

organic carbon content and other characteristics of the solid phase. Tolls and Sijm (2000) report 

that sorption affinity decreases with increasing LAS concentrations, which suggests that 

concentration dependency should be taken into account when assessing sorption of surfactants such 

as LAS. 

Temmink and Klapwijk (2004) also reported that sorption and desorption equilibria were achieved 

very rapidly for LAS in activated sludge, with sorption equilibrium achieved within 5-10 minutes. 

In other experiments conducted in a pilot scale treatment plant, 92-98% of the LAS was adsorbed to 

the sludge with only 2-8% present as dissolved LAS. Despite this high degree of sorption, more 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 16

than 99% of the LAS load was removed by biodegradation, showing that the adsorbed fraction as 

well as the soluble fraction of LAS is readily available for biodegradation. 

Mackay et al. (1996) conducted five-stage Level III fugacity modelling that included evaluative, 

regional and local-scale models. The level I and II models each resulted in LAS partitioning in air, 

water, soil and sediment at percentages of 0, 26, 56 and 18%, respectively. The overall residence 

time of LAS is predicted to be 100 hours with removal primarily by biodegradation in water (76%) 

and partitioning to sediment (13%). Impacts of LAS are predicted to be restricted to local receiving 

waters and their sediments and biota. In the Level III Fugacity Model, when discharges are directly 

to water, the residence time is predicted to be 33 hours and more than 99% remains in the water. 

However, in shallower receiving water more partitioning to sediments might be expected. When 

discharge is to soil, the residence time is predicted to be 28 days because of the slower 

biodegradation rate (compared to water) and little transfer to other media. Using the ChemCAN 4 

model and assuming 90% LAS discharge to soil and 10% to water, LAS partitioning in air, water, 

soil and sediment is predicted to be 0, 0.64, 99.35 and 0.004%. 

Level III fugacity modelling was also conducted by ECETOC (1993; reliability not assigned due to 

uncertainty regarding the input parameters) to predict LAS concentrations in air, biota, sediment, 

arable soil, suspended solids and water. LAS concentrations were predicted to be highest in soil 

and suspended solids. 

2.2.6 Biodegradation 

Biodegradation is the primary mechanism by which LAS is transformed, with the formation of 

sulfophenyl carboxylates (SPCs) as biodegradation intermediates (Swisher 1987; Schoeberl 1989; 

Huddleston and Allred 1963; dossier 3.5w). Longer alkyl chain LAS homologues undergo more 

rapid primary biodegradation to SPCs than shorter chain homologues (Bock and Wickbold 1966). 

SPC toxicities are several orders of magnitude lower than that of the parent material (Kimerle and 

Swisher 1977; dossier 4.1r, 4.2Af). SPCs also biodegrade as demonstrated by the rapid and 

complete biodegradation of LAS (to CO2, SO42-, and water) under aerobic conditions documented 

below. 

An extensive database of studies is available demonstrating rapid and complete biodegradation of 

LAS in freshwater under aerobic conditions (e.g., Ruffo et al. 1999; Nielsen and Huddleston 1981; 

dossier section 3.5). The studies summarized in Table 4 demonstrate that LAS passes standard tests 

for ready biodegradability, including the 10-day biodegradation window (Add refs). Rapid 

biodegradation of the iso-LAS components of LAS was also demonstrated by Cavalli et al. (1996) 

in a modified OECD 301E biodegradation study in which C11.6 LAS containing 5-6% iso-LAS 

was the sole source of carbon and the bacterial biomass was obtained from soil. Preliminary tests 

showed that more than 90% of the LAS disappeared within 4 days so additional LAS was added to 

the test system every fourth day over a 80-day test period. No accumulation of iso-LAS was 

observed in this study demonstrating that the iso-LAS components are just as biodegradable as 

LAS. Rapid biodegradation of LAS has also been demonstrated in marine systems, as shown by 

measured loss of LAS in salt water samples collected off the coast of Spain in which half-lives 

ranged from 3.4 to 13.8 days, with 4-9 days being the most frequent values (Vives-Rego et al. 

2000). 
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Table 4. Results of Aerobic Ready Biodegradation Studies on LAS 

Study, Protocol Endpoint 

Test Material 

Description 

(Average Alkyl 

Chain Length) 

Degradation 

Duration 

(days) 

Reference 

DOC Die-Away, 

Directive 79/83/EEC, 

Appendix V, C.4-A 

(OECD 301A) 

DOC Removal C11.6

93%; meets 10-

day window 

criterion 

28 

Schoeberl 1993b, 

dossier 3.5e; 

reliability = 1 

DOC Die-Away, 

Directive 79/83/EEC, 

Appendix V, C.4-A 

(OECD 301A) 

DOC Removal C11.6

94%; meets 10-

day window 

criterion 

28 

Schoeberl 1993c, 

dossier 3.5f; 

reliability = 1 

OECD 301B, 

Modified Sturm Test CO2 Production C11.6

66.7%; 10-day 

window not met 28 

Ruffo et al., 1999, 

dossier 3.5b; 

reliability = 1 

OECD 301B, 

Modified Sturm Test CO2 Production C11.6

83%; meets 10-

day window 

criterion 

28 

Enste-Diefenbach, 

2002, dossier 3.5z; 

reliability = 1 

Modified OECD 

Screening Test, 

Directive 

84/449/EEC, C.3 

(OECD 301E) 

DOC Removal C11.6

76%; meets 10-

day window 

criterion 

28 

European 

Commission 2000, 

dossier 3.5g; 

reliability = 4 

OECD Screening Test 

according to 

“Verordnung ueber 

die Abbaubarkeit 

anionischer und 

nichtionischer 

grenzflaechenaktiver 

Stoffe in Wasch- und 

Reinigungsmittel vom 

30.1.1977”. 

Bundesgesetzblatt 

Teil I, S. 244. 1977 

DOC Removal C11.6

95%; meets 10-

day window 

criterion 

19 

European 

Commission 2000, 

dossier 3.5i; 

reliability = 4 

While LAS degrades rapidly under aerobic conditions, it does not degrade under anaerobic 

conditions, except under special conditions. Denger and Cook (1999) showed that strains of 

anaerobic bacteria capable of degrading LAS (using it as a sulfur source) under sulfur-limiting 

conditions are present in nature. Sanz et al. (1999) were the first to demonstrate that LAS anaerobic 

biodegradation does occur under conditions that are not sulfur-limited, using anaerobic digester 

sludge and specific HPLC methods to measure the loss of the parent material. Prats et al. (2000) 

confirmed with specific HPLC analysis (loss of LAS) that LAS biodegrades anaerobically in the 

ECETOC-28 test, although increased gas production (mineralization) was not observed. Angelidaki 

et al. (2000a) demonstrated that degradation (loss of LAS) occurred under anaerobic conditions 

when exposed to inocula obtained from lake sediments or aerobic environments such as compost 

and activated sludge from a wastewater treatment plant. Anaerobic stabilized sewage sludge in 

continuous stirred reactors also showed a capacity to anaerobically degrade LAS, as measured by 

loss of parent material (Angelidaki et al. 2000b). Measurement of radiolabeled biogas and/or 

intermediates would be required for confirmation of these preliminary results. 

Degradation of LAS in soils has also been reported – see section 2.2.4 above. 
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2.2.7 Bioaccumulation 

The bioaccumulation potential of LAS has been investigated. Early studies, e.g., Kimerle et al. 

1981, used 14C-ring labelled LAS and measured only total radiolabeled materials, likely including 

LAS metabolites, and thus limiting the conclusions that can be drawn specific to LAS. Tolls et al. 

(1997) conducted a series of experiments with fathead minnows (Pimephales promelas) according 

to OECD Guideline 305E protocols in which the limitations of the earlier studies were overcome. 

Individual LAS homologues were tested in flow-through exposures for up to 192 hours for the 

uptake phase, followed by a depuration phase in which fish were transferred to unspiked water. The 

resulting bioconcentration factors (BCFs) ranged from 2 L/kg (6-phenyl-C10 LAS) to almost 1000 

L/kg (2-phenyl-C13 LAS), with BCF generally increasing with increasing alkyl chain length. BCF 

values were also calculated for a standard mixture (typical of LAS in European detergent 

formulations, average alkyl chain length = C11.6) and a representative environmental sample 

(filtered Mississippi river water, average alkyl chain length = C10.8). The respective BCFs were 87 

and 22 L/kg, indicating that the bioconcentration potential of LAS is decreased by environmental 

processes such as biodegradation and absorption, which reduce aquatic concentrations (Tolls et al. 

1997). These processes, as documented above, also preferentially remove longer alkyl chain length 

components, reducing the bioconcentration potential of the mixture fingerprint since the remaining 

lower alkyl chain materials have lower BCFs. 

2.2.8 Other Information on Environmental Fate 

In the US, monitoring in 50 wastewater treatment facilities in 11 states showed average LAS levels 

in raw sewage ranged from 4.2 to 5.7 mg/L (McAvoy et al. 1993) while levels in raw sewage from 

five European countries ranged from 4.0-15.1 mg/L (DiCorcia et al. 1994, Waters and Feijtel 1995). 

US monitoring data indicated that LAS is largely removed in wastewater treatment plants, 

averaging over 99% removal in activated sludge, 98% for lagoons/oxidation ditches, 96% for 

rotating biological contactors and 77-82% for trickling filters (McAvoy et al. 1993, Trehy et al. 

1996). Monitoring data from five European countries showed LAS removal in activated sludge 

treatment ranged from 98.5-99.9% (DiCorcia et al. 1994, Waters and Feijtel 1995) and averaged 

92.9% in four trickling filter plants in the U.K. (Holt et al. 2000). Results of a mass balance study 

of an activated sludge treatment plant indicate that removal is primarily due to biodegradation with 

only about 20% of the influent LAS removed with the sludge (DiCorcia et al. 1994). 

In the US, average concentrations in river water below treatment plant mixing zones were generally 

below 50 μg/L for samples collected under low dilution conditions (McAvoy et al. 1993, Trehy et 

al. 1996). Tabor and Barber (1996) reported LAS at concentrations ranging from non-detect (<0.1 

μg/L) to 28.2 μg/L in 362 water samples collected in an intensive sampling effort over the 2,800 km 

reach of the Mississippi River from Minneapolis to New Orleans. The alkyl chain length of the 

LAS in the water samples averaged 11.1 carbons, indicating preferential loss of the longer alkyl 

chain molecules, consistent with the sorption and biodegradation data discussed above. 

LAS river water concentrations similar to those in the US were observed in monitoring studies 

conducted in Europe and Japan. DiCorcia et al. (1994) found the LAS level in the Tiber River 

(Italy) below the Roma Nord treatment plant was 9.7 μg/L. Waters and Feijtel (1995) reported that 

LAS levels in river water below activated sludge treatment plants in five European countries ranged 

from <2.1 to 47 μg/L. Matthijs et al. (1999) found a mean LAS concentration of 14.2 μg/L in 

surface waters downstream, just past the mixing zone, of activated sludge treatment plants in the 

Netherlands. Fox et al. (2000) reported an LAS concentration, corrected for dilution, of 70 μg/L 4.8 

km (6 hours flow time) from the outfall of trickling filter treatment plant in the U.K. Gandolfi et al. 

(2000) found the mean LAS concentration in the Lambro River (Italy), where 40% of the local 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 19

wastewater was discharged untreated, was 28 μg/L. Nishiyama et al. (2003) reported that the 

median LAS concentration in water from 4 rivers (7 sites) in Japan was 6 μg/L (range <4-81). 

In river sediments, LAS concentrations were generally less than 1-2 mg/kg dry weight. LAS 

concentrations in Mississippi River sediments were generally <1 mg/kg, ranging from 0.01 to 0.95 

mg/kg (mean = 0.23 ± 0.19 mg/kg), with one outlier, a value of 20 mg/kg observed in an effluent 

transport canal (Tabor and Barber 1996). The average alkyl chain length of the sediment associated 

LAS was C11.5 (range C10.7-11.9). LAS concentrations in sediments of a small river (Rapid Creek, 

USA) below a trickling filter treatment plant averaged 190 mg/kg just below the outfall, 11.2 mg/kg 

less than 5 miles downstream and 5.3 mg/kg greater than 5 miles downstream (Rapaport and Eckoff 

1990). LAS levels in the receiving waters of the Tiber River (Italy) were 1.8 mg/kg in the 

sediments (DiCorcia et al. 1994). LAS concentrations in sediment below poorly functioning 

treatment plants or treatment plants having only primary treatment may be higher. 

LAS has been detected in seawater and marine sediments near the outfalls of untreated urban 

wastewaters or in highly polluted harbors (Bester et al. 2001, Leon et al. 2001, Temara et al. 2001, 

DelValls et al. 2002, Folke et al. 2002, Petrovic et al. 2002). LAS levels in three sets of seawater 

samples were less than or equal to 0.03 μg/L, 1-9 μg/L and 2.4-92 μg/L. In marine sediments, the 

absence of macrofauna and the presence of other components of wastewater, including other highly 

biodegradable compounds such as soap, indicate the impact of untreated wastewater discharge on 

these local environments. 

LAS concentrations (mean ± standard deviation) in sludge from US sewage treatment plants ranged 

from 150 (±120) mg/kg dry matter for aerobic digesters to 10,500 (±5,200) mg/kg dry matter for 

anaerobic digesters (McAvoy et al. 1993). Maximal LAS sludge levels reported in European 

monitoring studies were also generally less than 20,000 mg/kg (Berna et al. 1989, DiCorcia et al. 

1994, Waters and Feijtel 1995, Cavalli and Valtorta 1999, Carlsen et al. 2002). The one exception 

was an activated sludge plant treating wastewater with high hardness (500 ppm as CaCO3) in which 

the LAS levels in the digested sludge (30,200 mg/kg) likely represents calcium-precipitated LAS 

(Berna et al. 1989). 

In sludge-amended agricultural soils, LAS concentrations are generally less than 15 mg/kg dry 

weight, even immediately after sludge spreading. LAS concentrations in the U.K. in four fields 

spread within days of sludge application were 4.5, 7.8, 10.6 and 19.8 mg/kg, ranged from 0.2-2.1 

mg/kg in four fields spread two to three months previously and were less than 1 mg/kg (maximum 

concentration = 2.5 mg/kg) in 83% of the fields (n=42) spread the previous year (Waters et al. 

1989). In Denmark, a cultivated field spread with medium amounts of sludge (not further defined) 

had LAS concentrations of 1.12 mg/kg in the 0-10 cm depth and lower concentrations at lower 

depths (Carlsen et al. 2002). In the US, the presence of crop plants (barley, rape, or carrot) increased 

the degradation of LAS in soil (Mortensen et al. 2001). During degradation, the relative fraction of 

homologues C10, C11, C12 decreased, while C13 increased. 

E-FAST modeling of U.S. manufacturing facility effluent discharges (see Annex 1, Format C, 

Modeling Evaluation #1) resulted in estimated mean and low flow (7Q10) stream concentrations of 

4.8 μg/L and 13 μg/L, respectively. E-FAST modeling of down-the-drain disposal in the U.S. (see 

Annex 1, Format C, Modeling Evaluation #2) resulted in estimated median and 7Q10 (low flow) 

stream concentrations of 0.099 and 1.3 μg/L, respectively.1

 

1 US EPA did not evaluate the EFAST modeling results and therefore can make no conclusions regarding these values. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 20

2.3 Human Exposure 

2.3.1 Occupational Exposure 

LAS is manufactured from linear alkylbenzene (LAB) in self-contained, enclosed systems (see 

Annex for more information). LAB is produced by reacting paraffins with benzene and a catalyst 

and isolating the LAB by distillation. The LAB is then sulfonated, which in turn is then neutralized 

to sodium salts of LAS. Exposure to industrial workers is limited because this is an enclosed 

manufacturing process designed to minimize losses and the potential for release (see Annex). 

Worker exposure is possible during the detergent formulation stage by inhalation of powders or 

dermal contact of powders and liquids. However, good manufacturing design practices (e.g., 

enclosed production, exhaust ventilation, dust collection) and personal protective equipment (e.g., 

protective clothing, eyewear, and gloves) are in place at facilities that manufacture liquid and dry 

(granular/powder) materials to mitigate worker exposure to LAS. No special engineering controls 

or additional personal protective equipment are uniquely specified for LAS (LAS SIDS Coalition 

Survey 2002). 

2.3.2 Consumer Exposure 

The greatest potential for exposure of humans to LAS is associated with consumer use of laundry 

and cleaning products. Consumer exposure could result from direct or indirect skin or eye contact, 

inhalation of aerosols from cleaning sprays, and oral ingestion of residues deposited on dishes, 

accidental product ingestion, or indirectly from drinking water. Based on exposure modeling 

(Annex 1), the greatest potential of LAS exposure is from pretreatment of laundry, due to direct 

hand and forearm contact with neat product formulations, and from residual product on laundry 

clothing due to the large surface area of the body in contact with clothing. 

Exposure to LAS in these formulated laundry or cleaning products is mitigated by following use 

and precaution instructions on product labels. Product labels reflect the hazard potential of the 

ingredients in the product under foreseeable use conditions. These product labels also include first 

aid instructions to accompany each hazard warning. For example, products may include eye and/or 

skin irritancy warnings along with instructions to rinse thoroughly if dermal or other exposure 

occurs. 

Laundry and cleaning products may be used as is, or diluted prior to or during use. Human 

exposure will be further mitigated by the fact that residues on skin from cleaning products are 

usually washed or rinsed off. Actual dermal absorption is less than 1% of product (Schaefer and 

Redelmeier 1996). 

Modeling of exposure potential from use of consumer products (see Annex) resulted in estimated 

exposures of 5.6 x 10-2 to 4.7 x 10-5 mg/kg/day. Modeling of potential aquatic exposures and 

human exposures from down-the-drain releases from consumer use of products containing LAS 

resulted in estimated exposures of 1.9 x 10-6 mg/kg/day and 7.2 x 10-7 mg/kg/day for drinking water 

and fish consumption, respectively. These human exposure evaluations include conservative 

(protective) input assumptions, e.g. all dermal modeled exposures use a default assumption of 100% 

absorption vs. a measured value of <1%. 

It is important to note that the laboratory exposure from the summarized inhalation study (Kinney 

1985; see SIAR section 3.1.2) is not representative of the possible LAS exposure during actual 

production or use. In the Kinney study, animals were given high exposures to respirable-sized 

particles (MMAD = 2.5 microns). However, spray products containing LAS are designed to 
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produce large particle sizes. These large particles are needed for efficient delivery of the spray to 

the surface being cleaned. This results in particle sizes that are much larger than the respirable 

particle sizes used in testing and therefore would not be able to reach far into the lungs where 

effects could occur. A study conducted for the Soap and Detergent Association (Battelle 1999) 

measured the under 10 micron fraction delivered from 6 consumer product spray nozzles. The 

overall mean (n=30) is 0.11% particles under 10 microns and the standard deviation is 0.21. The 

very highest observation was 0.80% particles under 10 microns. This testing only captured the 

spray particles that are under 600 microns, so the actual mean respirable particle percent of total 

volume sprayed is less than 0.1%. The Battelle (1999) study also reported that for consumer spray 

products in normal use conditions, the peak breathing zone concentration under 10 microns ranged 

from 0.13-0.72 mg/m3

. HERA (2004) reported that measurements of aerosol particles under 6.4 

microns in size generated upon spraying with typical surface cleaning spray products resulted in a 

product concentration of 0.35 mg/m3. 

Inhalation of detergent dust during washing processes was modelled by HERA (2004) and found to 

be 10-fold lower than the exposure from inhalation of aerosols from cleaning sprays. This estimate 

is based on a study reporting an average release of 0.27 μg dust per cup of product used for machine 

laundering (Hendricks, 1970). This is a conservative (protective) estimate as exposure from modern 

compact/granular detergent formulations produced in agglomeration processes would be expected 

to be much less. 

These estimates of exposure to respirable particles from consumer and industrial products indicate 

that inhalation is not a likely route of concern for human exposure (see SIAR Annex 1 and dossier 

section 1.10B(b) and (c) for more information).2

3 HUMAN HEALTH HAZARDS 

3.1 Effects on Human Health 

3.1.1 Toxicokinetics, Metabolism and Distribution 

Studies in Animals

The absorption, distribution, metabolism and elimination of LAS has been studied in several 

species, including rats, mice, guinea pigs, pigs, and rhesus monkeys (Debane 1978; Michael 1968; 

Havermann and Menke 1959; Cresswell et al. 1978; Sunakawa et al. 1979). LAS was administered 

either topically (i.e., dermally) or orally. Results showed that LAS can be absorbed from the 

gastrointestinal tract. Absorbed LAS is then metabolized and excreted without accumulation in the 

major tissues or fat. 

Debane (1978) found that when 0.2 to 0.5% LAS was topically applied once to the back skin of rats 

and guinea pigs, approximately 0.1 to 0.6% was absorbed. No accumulation was observed in 

specific organs and LAS was quickly excreted in the urine after being metabolized. IPCS (1996) 

notes that prolonged contact with the skin may compromise the integrity of the epidermal barrier, 

thereby potentially permitting greater absorption from this route. Michael (1968) found that LAS 

administered orally as an aqueous solution was readily absorbed from the gastrointestinal tract (80-

90% of the dose). Most of the absorbed dose was eliminated within 72 hours and 60-65% was 

 

2 US EPA did not evaluate the modeling results in Annex 1 and therefore can make no conclusions regarding these 

values. 
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eliminated via the urine, with sulfophenyl butanoic and sulfophenyl pentatonic acid as metabolites. 

Approximately 35% of the absorbed dose was excreted in the bile. Although the metabolites in the 

bile were not identified, it was shown that no unchanged LAS was eliminated via this pathway. In 

oral studies with pigs, Havermann and Menke (1959) found that at 200 hours after oral 

administration, the radiolabeled LAS was relatively high in bristles and bones, while low in liver, 

kidney and spleen. After 10 weeks only traces of radioactivity were still in the body. At 40 hours 

after administration, 40% of the dose was excreted into the urine and 60% of the dose via the feces. 

In another study (Sunakawa et al. 1979), rats were dosed orally with 14C-LAS and radioactivity 

was detected 0.25 hours after administraton, reaching a maximum at 2 hours. The biological halflife was calculated to be 10.9 hours. The distribution was high in the digestive tract and in the 

bladder at 4 hours after administration, with high concentrations also found in the liver, kidney, 

testis, spleen and lung. At 168 hours after administration, the rates of excreted radioactivity were 

47% in the urine and 50% in the feces. 

Toxicokinetics has also been studied in adult rhesus monkeys (Cresswell et al. 1978). Two male 

and two female monkeys were given single or repeated oral (30, 150 or 300 mg/kg) or subcutaneous 

(0.1, 0.5 or 1 mg/kg) doses of 14C-LAS. For example, after single 30 mg/kg oral doses, the 

radioactivity was rapidly excreted, mostly during the first 24 hours. Means of 71.2% and 23.1% of 

the dose were excreted in the urine and feces, respectively, during 5 days. During seven 

consecutive daily (30 mg/kg/day) or subcutaneous (1 mg/kg/day) doses, there was no accumulation 

of radioactivity in plasma. Mean peak concentrations and biological half-lives were similar after 

the first and seventh doses. No unchanged LAS was detected in the urine after oral or subcutaneous 

doses. Five metabolites were excreted but they were not identified. 

Studies in Humans

Studies were conducted with isolated human skin preparations using two solutions of C12 LAS 

(Howes 1975). The results demonstrated that penetration through the skin and subsequent 

absorption does not occur to any significant extent (less than 1%) at 24 to 48 hours. 

3.1.2 Acute Toxicity 

Acute mammalian toxicity data are available for all three potential routes of exposure (inhalation, 

dermal, oral), as summarized below and in Table 5. 

Studies in Animals

Oral 

Eight acute oral toxicity studies are available for LAS using rats, and one acute oral study is 

available using mice (Murmann 1984a,b,c; Ito et al. 1978; Kynoch 1986a; Monsanto 1971, 

1972a,b). All of the studies were conducted on the low average chain length LAS (C11.2-C11.7). 

The resultant LD50 values ranged from 1,080 up to 1,980 mg/kg bw for rats and greater than 2000 

mg/kg bw for mice, with no significant difference between sexes. Mortality and symptoms of 

toxicity occurred at the high doses tested in each study, and usually within the first few hours or 

days, after which surviving animals generally recovered. Symptoms noted in most of the studies 

included piloerection, hunched posture, abnormal gait (waddling), lethargy, reduced appetite, 

decreased respiratory rate, ptosis, pallor of the extremities, and diarrhea. All oral studies are 

reliability 1 or 2, except for those by Ito et al. (1978), which were rated unassignable (4) since the 

original reports were not available for review. However, these studies were considered reliable 

because they have been reviewed by the International Program on Chemical Safety. 
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Dermal 

The acute dermal toxicity of LAS was studied in rats under OECD Guideline 402 and GLP 

conditions (Kynoch 1986b). The LAS used in this study was C11.2 LAS, which has an average alkyl 

chain length slightly shorter than the range of chain lengths currently used in the United States 

(C11.2-C12.6). There were no deaths or systemic reaction to five male and five female rats following 

a single dermal application of 2000 mg/kg bw of LAS at 47% active matter. Well defined or slight 

erythema and slight edema were observed at all test sites after removal of the occlusive dressing on 

Day 2. All test sites were entirely covered by scab formation from Day 7. Sloughing from the 

scabbed skin began at various times between Day 7 and Day 12 and was completed before 

termination. Low bodyweight gains or loss of body weight were recorded for one male and three 

females in Day 8. Two of the same females and a third female also showed low bodyweight gain 

between Days 8 and 15. Terminal necropsy findings were normal. Additional dermal toxicity studies 

(Monsanto 1971, 1972a, b) are included in Table 5 but the reliability was rated unassignable (4) due 

to deficiencies in the number of animals per dose. 

Inhalation 

Acute inhalation data are available for LAS (CAS #25155-30-0; Kinney 1985). In this reliability 2 

study, groups of six 8-week old rats underwent nose-only exposures to aerosol atmospheres 

containing 65, 120, 260 or 310 mg/m3

 respirable-sized particulate LAS (MMAD = 2.5 microns) for 

4 hours, followed by 14 days of observations for clinical signs. No mortality occurred at 

concentrations up to 260 mg/m3

. At 310 mg/m3, one rat died during the exposure and two rats died 

one day post exposure. Given these results C12-LAS is considered moderately toxic by inhalation 

(see SIAR section 2.3.2 for discussion of inhalation exposure). 

Conclusion

The available acute toxicity data by the oral route of exposure indicate that LAS exhibits slight 

acute oral toxicity, with symptoms of toxicity and mortality at high doses but not at lower doses. 

LD50 values for rats and mice range from 1,080 to 1,980 mg/kg bw. No effects were observed in 

dermal exposure studies with rats at 2,000 mg/kg bw, indicating low dermal hazard potential. 

Inhalation toxicity data indicate that LAS is moderately toxic, with mortality occurring at respirable 

particle concentrations of 310 mg/m3

 (MMAD = 2.5 microns). However, less than 0.1% of the total 

volume sprayed from consumer product spray nozzles consists of respirable particles. Estimates of 

exposures from consumer spray products indicate that inhalation is not a route of concern. 
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Table 5. Acute Toxicity to Mammalian Species 

Species Route of Exposure 

LD50 (mg/kg bw 

unless otherwise 

specified) 

Doses (mg/kg bw) Reference 

(Reliability) 

Rat Oral 1080 1075, 1220, 1360, 

1710 Murmann 1984a (2) 

Rat Oral 1630 1260, 1580, 1785, 

1990 Murmann 1984b (2) 

Rat Oral 1410 1190, 1500, 1890 Murmann 1984c (2) 

Rat Oral 1460 (males) 

1470 (females) - Ito et al. 1978 (4) 

Rat Oral 1980 1500, 2350, 3760 Kynoch 1986a (1) 

Rat Oral 1320 1000, 1260, 1580 Monsanto 1971 (2) 

Rat Oral 1430 1000, 1260, 1580, 

2000 Monsanto 1972a (2) 

Rat Oral 1360 1000, 1260, 1580, 

2000 Monsanto 1972b (2) 

Mouse Oral 2160 (males) 

2250 (females) - Ito et al. 1978 (4) 

Rat Inhalation 310 mg/m3 * 65, 120, 260, 310 

mg/m3 Kinney 1985 (2) 

Rat Dermal > 2000 2000 Kynoch 1986b (1) 

Rabbit Dermal > 200 and < 316 

126, 200, 316, 501, 

794, 1260, 2000, 

3160, 5010 

Monsanto 1971 (4) 

Rabbit Dermal > 631 and < 1000 200, 316, 631, 1000, 

1260, 2000, 3160 Monsanto 1972a (4) 

Rabbit Dermal > 631 and < 1000 200, 398, 631, 1000, 

1260, 2000, 3160 Monsanto 1972b (4) 

Rat subcutaneous 840 (males) 

810 (females) - Ito et al. 1978 (4) 

Mouse subcutaneous 1250 (males) 

1400 (females) - Ito et al. 1978 (4) 

Rat intravenous 119 (males) 

126 (females) - Ito et al. 1978 (4) 

Mouse intravenous 207 (males) 

298 (females) - Ito et al. 1978 (4) 

Mouse intravenous 115 (C10-LAS) 

105 (C12-LAS) - Hopper et al. 1949 

(2) 

* Value is Approximate Lethal Concentration 
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3.1.3 Irritation 

Skin Irritation

Several skin irritation studies have been conducted on rabbits for LAS at a concentration of about 

50% (Liggett and Parcell 1986a; Biolab 1989a; Kaestner 1997; Murmann 1983a). Findings in all 

the studies were consistent and showed similar irritation effects, as would be expected with a 

surface active agent. 

In the most reliable study (Liggett and Parcell 1986a), conducted under OECD protocols and GLP 

conditions, a 47% LAS concentration was applied to the clipped intact skin of three rabbits. Well 

defined to moderate skin reactions were observed in all three animals, as was desquamation of the 

stratum corneum. These reactions gradually ameliorated from days 5, 10, and 11, respectively, and 

had resolved completely in one animal by day 12. Similar results were observed in studies of 50% 

concentration LAS reported by Biolab (1989a), Kaestner (1997), and Murmann 1983a. Several 

older studies conducted on a neat commercial LAS material (0.5 g moistened with water) resulted in 

a classification as a severe skin irritant (Monsanto 1971, 1972a,b). 

Additional skin irritation studies have been conducted with lower concentrations of LAS (Biolab 

1989b,c,d). At 1% and 2.5% LAS, no skin irritation was observed in rabbits following exposure 

under OECD Guidelines. At 5%, LAS was classified as a moderate skin irritant. 

Eye Irritation

Several eye irritation studies on rabbits are available for LAS at a concentration of about 50% 

(Liggett and Parcell 1986b; Biolab 1989d; Murmann 1983b; and Kaestner 1987). All studies had 

consistent findings and showed significant irritation effects. 

The most reliable study (Liggett and Parcell 1986b) was performed under OECD Guidelines and 

GLP conditions in which each of three rabbits received LAS at 47% placed into the lower everted 

lid of one eye. Significant conjunctivae chemosis was observed in all animals, with minor effects 

on cornea opacity and conjunctivae redness in two animals. One animal showed significant ocular 

reactions in all sites, which had not cleared at day 14. Concurrent with this study, the eyes of other 

rabbits were rinsed following 4 or 30 second eye exposures. Irritation was still present but 

diminished after the 30 second rinsing and only slight after the 4 second rinsing. Other studies of 

50% LAS conducted on rabbits using OECD Guidelines also resulted in a classification of irritating 

with effects noted in the iris and conjunctivae that were persistent at day 6 (Biolab 1989d; Murmann 

1983b). 

In two Japanese studies conducted on LAS tested at low concentrations (Oba et al. 1968; Iimori et 

al. 1972), no abnormalities were seen at 0.01% but slight congestion was seen at 0.05% and 

considerable congestion was seen at 0.1% that disappeared within 24 hours. Marked responses 

were observed at 0.5% LAS and higher, including severe congestion and edema, increased 

secretion, turbidity of the cornea, and disappearance of the corneal reflex. These effects 

disappeared completely after 120 hours. The results of two additional rabbit studies conducted 

under OECD Guidelines indicated no irritation at 1% LAS but marked reactions for conjunctival 

redness and chemosis at 5% (Biolab 1984). Finally, three older non-standard studies are available 

in which 100 mg of finely ground solid commercial LAS sample was placed in the eyes of rabbits 

(Monsanto 1971, 1972a,b). The resultant scores ranged from 10 to 19 out of 110, which classifies 

this as a mild irritant. 

Comparisons between animal test results and human eye irritation experiences indicate that the 

rabbit eye irritation test is not well correlated to human responses for 29 surfactant-based cleaning 

products. Human experience with eye exposure to surfactants was reported by Freeberg et al (1984) 
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and coworkers (Freeberg et al. 1986, Cormier et al. 1995). These studies investigated exposure of 

manufacturing employees and consumers to laundry, household and personal cleaning products 

containing LAS and other chemicals. While concentrations were not reported in the Freeberg et al. 

publications, the coalition survey indicates that LAS concentrations in US consumer products range 

from 0.1-25% and in commercial products from 1-30%, with the exception of one reported product 

at 45% in concentrated form that is mechanically dispensed into dilution for dishwashing. The 

results of the Freeberg et al. studies indicate that in accidental exposure situations, the effects were 

moderate, transient and reversible. In the Freeberg et al. (1984) study (n=514), 88.1% of the eyes 

cleared in 4 days or less with no reported permanent eye damage. All eyes cleared in 28 days. 

Labeling of consumer products containing LAS and other surfactants include warnings of the 

potential for eye irritation and with first aid instruction to rinse with water. 

Conclusion (Skin and Eye Irritation)

LAS was found to be not irritating to skin at concentrations of 1% and 2.5%, moderately irritating 

at 5%, and more severely irritating at higher concentrations of about 47-50%. LAS is generally not 

irritating to the eyes of rabbits at concentrations up to about 1% (some congestion does occur at 

0.05-0.5%), moderately irritating at 5%, and more severely irritating at 47-50%. At these higher 

concentrations the irritation may be present for up to 14 days. In studies that included rinsing, 

irritation effects diminished with rinsing after 30 seconds of exposure and were slight with rinsing 

after 4 seconds of exposure. Human experience has established that irritation effects of consumer 

products containing LAS and other surfactants are moderate, transient and reversible. 

3.1.4 Sensitization 

Studies in Animals

Three studies are reported in which skin sensitization in guinea pigs was examined (RBM 1985 

[dossier section 5.3c]; Murmann 1988 [dossier section 5.3b]; European Commission 2000 [dossier 

section 5.3a]). Studies were conducted according to OECD Guidelines and used induction 

concentrations of 1, 3 or 25% LAS. No sensitization was observed. A.D. Little (1991) reported 

that LAS may be a weak sensitizer in guinea pigs under exaggerated exposure conditions (e.g., 

injection induction), but that clear no-effect levels were well below anticipated exposure levels. 

Studies in Humans

Human exposure studies, with volunteers who provided informed consent, are also available for 

LAS. In a repeat insult patch test, LAS was applied at 0.10% to the upper arms of 95 volunteers 

(Procter & Gamble, unpublished data). The 24 hour exposure was repeated 3 times a week for 3 

weeks during the induction period. After a 14-17 day rest, a 24-hour challenge patch was applied. 

No evidence of skin sensitization occurred in any of the 95 volunteers. Nusair et al. (1988) 

conducted extensive patch tests in which 2,294 volunteers were exposed to LAS as a raw material 

and 17,887 were exposed to LAS in formulations. Again, no evidence of sensitization was 

observed. In a study reported in the IUCLID Data Set, LAS was found to be sufficiently 

compatible with the skin after it was applied as a 1% solution to the skin of middle Europeans 

(Matthies 1989). 

Conclusions

Skin sensitization studies with guinea pigs showed no sensitization at either lower (6.7%) or higher 

(50%) concentrations. Results of animal studies, human exposure studies and actual use support the 

conclusion that LAS does not have significant skin sensitization properties. 
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3.1.5 Repeated Dose Toxicity 

Numerous repeated dose toxicity studies are available, and include studies on rats, mice, and rhesus 

monkeys and oral, dermal, and drinking water exposures. The results are summarized in Table 6. 

Studies in Animals

Oral 

Many studies have investigated the effects of repeated doses of LAS via the oral exposure route, 

mainly in the feed but also by gavage and through the drinking water. In a key study, groups of 8 or 

9 rats of each sex were given LAS in drinking water at equivalent doses of 85, 145, and 430 mg/kg 

bw/day for 9 months (Yoneyama et al. 1976). Body weight gain was suppressed in the male 430 

mg/kg bw/day group. Hematological examination revealed no significant change in any of the 

experimental groups, but a dose-related decrease in cholesterol level was seen in males. Significant 

decreases in the activities of glutamate-oxalate transaminase and lactate dehydrogenase were seen in 

males at the middle dose and a dose-related increase in the activity of glutamate-oxalate transaminase 

in females. A significant decrease in renal Na,K-ATPase was seen in the middle-dose group. No 

organ weight changes were observed. The NOAEL is 85 mg/kg bw/day. 

Other studies show similar responses, with commonly reported effects at higher doses including 

diarrhea, suppression of body weight gain, increases in relative weight of the liver, changes in other 

organ weights, differences in enzymatic and serum-biochemical parameters (e.g., ATPase, LDH, 

G6Pase), and mild degeneration and desquamation of the tubular epithelium in the kidneys. 

Occasionally, other effects have been observed, including marked degeneration of renal tubes, 

proteinaceous degeneration in the liver, and effects on subcellular components (Yoneyama et al. 

1972; Gupta et al. 1986; Mathur et al. 1986; Watari et al., 1977). 

Dermal 

LAS was applied for 15 days to the backs of male Wistar rats at daily doses of 0.5 g of solutions at 

20 and 30% (about 286 and 427 mg/kg bw/day) (Sadai and Mizuno 1972). Body weight gain was 

suppressed in the 20% group and the body weight was decreased in the 30% group. An infiltrating, 

yellowish-reddish brown crust was observed 2-3 days in the 20% group, and at 1-2 days in the 30% 

group. At 4-6 days the crust was abraded and erosion occurred at the abraded site. Histological 

examinations of the application site revealed severe necrosis of the region from the epidermis cuticle 

to the upper layer of the dermis, severe infiltration of leukocytes in the necrotic site, diffuse 

inflammatory cell infiltration of all layers of the corium. No changes were observed in the tongue, but 

the oral mucosa revealed atrophy and slight degeneration of the epithelium. No systemic effects were 

observed. The effects on body weight are considered to be related to LAS irritation. Therefore, the 

local LOAEL for dermal exposure from this study in rats is 286 mg/kg bw/day. 

Inhalation 

No long term studies on LAS inhalation are available. Based on its irritant nature, it is expected 

that repeat inhalation of LAS might be irritating to the respiratory tract. 

Conclusion

LAS has been tested for toxicity resulting from repeated exposures via the oral and dermal routes in 

rodents (rats and mice) and non-rodents (monkeys). Test durations ranged from 15 days up to 9 

months and exposure doses ranged from 8.8 up to 1,030 mg/kg bw/day. LOAELs ranged from 115 

to 750 mg/kg bw/day and the highest NOAEL (below the lowest LOAEL) is 85 mg/kg bw/day. This 

overall NOAEL was selected as the most appropriate value based on the study duration (9 months) 

and the data from all the studies. 
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It should be noted that several of the key studies are given a reliability score of 4. This score was assigned 

because the original reports were not available for review; however, these studies were evaluated and 

included in the IPCS review of LAS (IPCS 1996) and therefore are considered to be reliable for the purposes 

of this SIDS assessment. A weight of evidence approach was used to consider the data from all studies. The 

Yoneyama et al. (1976) study was highlighted because it reports the highest NOAEL below the lowest 

LOAEL from all the studies.

Table 6. Summary of Repeated Dose Toxicity Tests 

Species Route of 

Exposure 

Study 

Duration 

NOAEL 

(mg/kg 

bw/day) 

LOAEL 

(mg/kg 

bw/day) 

Doses 

(mg/kg 

bw/day) 

Reference 

Rat Oral feed 12 weeks 50 250 50, 250 Oser and Morgareidge 

1965 

Rat Oral feed 90 days 220 - 8.8, 44, 220 Kay et al. 1965 

Rat Gavage 30 days 125 250 125, 250, 500 Ito et al. 1978 

Rat Oral feed Up to 12 

weeks - 750 750 Ikawa et al. 1978 

Rat Oral feed 6 months 40 115 40, 115, 340, 

1030 Yoneyama et al 1972 

Rat Gavage 10 weeks - 50* 50, 100, 250 Gupta et al. 1986; Mathur 

et al. 1986 

Rat Oral feed 9 months - 260 260, 780 Yoneyama et al. 1976 

Rat Drinking 

water 9 months 85 145 85, 145, 430 Yoneyama et al. 1976 

Rat Oral feed 2 years 250 - 10, 50, 250 Buehler et al. 1971 

Rat Drinking 

water 2 years 200 - 20, 100, 200 Tiba 1972 

Mouse Drinking 

water 6 months - 20#

 20 Watari et al. 1977 

Mouse Oral feed 9 months - 500 500, 1000 Yoneyama et al. 1976 

Mouse Drinking 

water 9 months 250 600 100, 250, 600, 900 Yoneyama et al. 1976 

Monkey Gavage + sc 

injection 28 days 30 (oral) + 0.1 (sc) 

150 (oral) + 

0.5 (sc) 

30, 150, 300 

(oral) + 0.1, 

0.5, 1.0 (sc) 

Heywood et al. 1978 

Rat Dermal 15 days - 286 286, 427 Sadai and Mizuno 1972 

*

Although ultrastructural changes in liver cells were observed in the study, the changes were considered minimal 

and reversible. Effects have not been seen at similar doses in other studies that used techniques that are 

commonly applied in standard toxicity study protocols; in this study additional techniques were applied. 

Therefore, this value was considered a LOEL rather than an LOAEL. 

# Watari et al. (1977) administered LAS to mice (number and sex not reported) for 6 months at an equivalent 

dose of 20 mg/kg bw day in drinking water. Atrophy of the golgi apparatus, degeneration of the mitochondria, 

and increased appearance of lysosomes were observed in liver cells. Effects on the rough endoplasmic 

reticulum were observed. The severity of these cellular effects was dependent on the length of the 

administration. After six months, some liver cells showed degenerative cytoplasm and indications of cell 

necrosis. Some animals still showed cellular effects after the two months post administration while other 

animals showed full recovery. No other effects were reported. It is unclear how often these effects would be 

observed in other studies, if those studies also used electron microscopy. However, based on the use of a single 

dose (i.e., no dose response information) and the likelihood of dehydration in the dosed animals it was decided 

that 20 mg/kg bw day was better presented as a LOEL. 
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3.1.6 Genetic Toxicity 

In vitro Studies

Several in vitro bacterial (Ames) tests have been conducted on LAS using Salmonella typhimurium 

TA 98, TA 100, TA 1535, TA 1537, and TA 1538 strains with and without metabolic activation at 

test material concentrations up to 5000 μg/plate (Schoeberl 1993a; Inoue et al. 1980; Sunakawa et 

al. 1981). Results were negative in all studies, while the positive and negative controls gave the 

expected results. Similarly, results with and without activation were negative in a recombination 

assay using Bacillus subtilis at concentrations up to 50 μg/plate and in an E. coli reverse mutation 

assay (Inoue and Sunakawa 1979). 

A transformation test with Syrian hamster embryo (SHE) cells without metabolic activation also 

showed negative results (Inoue et al. 1980). 

In vivo Studies

In vivo mammalian bone marrow cytogenetic studies on LAS exposure are available in which mice 

received either oral gavage doses up to 800 mg/kg bw/day (Inoue et al. 1977) or dietary doses up to 

1170 mg/kg (Masabuchi et al. 1976). Rats were also given dietary doses up to 450 mg/kg bw/day 

(Masabuchi et al. 1976). In all studies, there was no significant difference in the incidence of 

chromosomal aberrations between the treated groups and the control groups. A dominant lethal 

assay with mice is also available in which male mice received LAS in the diet at a dose of 300 mg/kg 

bw/day for 9 months before being mated with untreated females (Masabuchi et al. 1976). There were 

no significant differences in fertility, the mortality of ova and embryos, the number of surviving 

fetuses, or the index of dominant lethal induction between the experimental groups and the control 

group. Three male mice each given a single intraperitoneal injection of 100 mg/kg bw LAS showed 

no differences in the incidences of polychromatic erythrocytes with micronuclei in the bone marrow 

between the control and treatment group (Kishi et al. 1984). The reliability of each of the in vivo 

studies reported here was not assignable because the original study reports were not available for 

review. However, they had been evaluated by the International Program of Chemical Safety (IPCS 

1996) and therefore are considered reliable. 

Conclusion

No indication of genetic toxicity for LAS is evident in any of the studies conducted. 

3.1.7 Carcinogenicity 

Several studies looked at the potential for tumorigenicity in rats. In the most documented study 

(Buehler et al. 1971), four groups of Charles River weanling rats, divided by sex, were given 0.5, 

0.1, and 0.02% (10, 50, 250 mg/kg bw/day) LAS in their food for 2 years. Following completion of 

those studies, five male and five female rats from each of the parental groups (F1b and F2b) and all 

survivors were selected for necropsy. Gross examination of all animals for pathology did not reveal 

any abnormalities. No consistent dietary induced changes that could be considered a toxic response 

were observed. Animals that showed significant loss of weight, development of tumors, or other 

evidence of abnormalities were sacrificed and tissues examined. The incidence of tumors and the 

common incidental diseases were similar in all dieting groups. 

Other rat studies had similar results with drinking water exposures up to 200 mg/kg bw/day for 24-

26 months (Tiba 1972; Endo et al. 1980) or dietary exposures up to 300 mg/kg bw/day for up to 24 

months (Fujii et al. 1977; Yoneyama et al. 1977). No effects were observed on survival, body 

weight gain, or general histopathology and hematological endpoints. Slight increases in liver and 
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cecum weight, biochemical activity (GOT, GTP, ALP, bilirubin), and looseness, atrophy and fatty 

change of hepatic cells in the liver were sometimes reported. No evidence of tumorigenesis was 

observed. Note that the IPCS report (1996) concluded that these studies were inadequate to 

evaluate the carcinogenic potential of LAS. 

Conclusion

Several studies investigated the tumorigenic potential of LAS. While the quality and focus of the 

studies preclude a definitive assessment, the results do not show evidence of carcinogenicity 

3.1.8 Reproductive Toxicity 

Three separate reproductive toxicity studies are available in which rats were exposed to LAS for up 

to four generations. One publication (Buehler et al. 1971) reported the results of the carcinogenicity 

study discussed above plus a separate three-generation reproductive study. 

In that three-generation study, rats were given the sodium salt of C10-14 LAS in the diet for 

approximately 2 years (Buehler et al. 1971). Four groups of male and female weanling rats 

received dietary doses equivalent to 14, 70 and 350 mg/kg bw d, with 50 animals of each sex per 

dose group. All reproductive parameters, including fertility, gestation, parturition, neonatal 

viability, lactation, and post-weaning growth were normal for all test groups. In addition, no 

definitive adverse effects in hematology and pathology or gross abnormalities were noted. 

Therefore, the reproductive NOAEL is 350 mg/kg bw/day. Similarly, a commercial light duty 

liquid detergent (CLD) containing 17% LAS and 7% alkyl ether sulfate was administered in the diet 

to three generations of CD strain rats at doses equivalent to 40, 200 and 1000 mg/kg bw/day CLD 

(Palmer et al. 1974). Again, no treatment-related effects on general parental toxicity or toxicity to 

the offspring was observed over the course of the study, and the NOAEL is 1000 mg/kg bw/day 

CLD (corresponding to 170 mg/kg bw LAS). In the third available study, two groups of 20 Wistar 

rats of each sex were given a dose equivalent to 70 mg/kg bw/day in their drinking water and 

evaluated for reproductive performance over 4 generations (Endo et al. 1980). The administration 

of LAS had no adverse effects on fertility, parturition, gestation period, or lactation in any of the 

generations. The corresponding NOAEL for this study is therefore 70 mg/kg bw/day. Note that the 

IPCS report (1996) concluded that many of these studies had some inadequacies and recommended 

definitive studies to be carried out; however, the data are adequate for a weight of evidence approach. 

In support of this data, two repeated dose studies (Kay et al. 1966 (dossier 5.4b; Buchler et al. 1971; 

dossier 5.4k) examined organ weights and histopathology of various organs including the gonads 

and reported that no adverse effects were observed in a 90-day oral feed study in rats at doses as 

high as 220 mg/kg bw/day (highest dose tested) or in a 2-year oral feed study in rats at doses as high 

as 250 mg/kg bw/day (highest dose tested). The absence of reproductive organ effects in these 

studies adds to the weight of evidence that LAS is not a reproductive toxicant. 

Conclusion

No effects on reproduction were observed in any of the three available reproductive toxicity studies 

in which rats were given dietary doses over three to four generations. No effects on gonadal 

weights or histopathology were observed in 90-day and 2-year repeated dose studies. The results of 

the repeated dose and reproductive toxicity studies collectively provide strong weight-of evidence 

support that LAS is not a reproductive toxicant. Given the consistent lack of effects, the highest 

dose tested (350 mg/kg bw/day) should be considered the highest NOAEL. The range of NOAELs 

was 70 to 350 mg/kg bw/day for the five studies. 
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3.1.9 Developmental Toxicity 

A substantial number of studies have been conducted to determine the developmental toxicity and 

teratogenicity characteristics of LAS. These studies have included exposures to several species 

(rats, rabbits, mice) by the oral route via gavage, in the diet, or in the drinking water, and by the 

dermal exposure route. Table 7 summarizes the maternal and fetal data from the available 

developmental studies. 

Oral exposure 

In one representative oral exposure study, LAS at a dose of 0.1% was administered to 40 female 

rats and 22 female rabbits in drinking water from day 6 to 15 (rats) and day 6 to 18 (rabbits) of 

pregnancy (Endo et al. 1980; European Commission 2000). This dose corresponds to 70 and 250 

mg/kg bw/day for rats and rabbits, respectively. The only effect on the dams was a slight inhibition 

of body weight gain in the rabbits. No significant effects were observed in the litter parameters of 

both species as compared to the controls. Delayed ossification was observed in rabbits, but there 

was no increase in malformations in either the rabbits or the rats. Consequently, the fetal LOAEL 

for the rabbit is 250 mg/kg bw/day, which is also the maternal LOAEL. The NOAELs (maternal 

and fetal) for the rat are 70 mg/kg bw/day. 

Maternal effects in other oral exposure studies ranged from no effects to severe toxicity and death in 

some studies. Common effects included decreased body weights, gastrointestinal effects, and 

diarrhea. Some studies resulted in anorexia. In two oral feed studies, no maternal effects were 

observed (Nolen et al., 1975; Tiba et al., 1976). However, in four gavage studies, deaths occurred at 

higher doses tested. Specifically, 1 CD rat died at 600 mg/kg bw/day, although this effect was not 

conclusively related to treatment (Palmer et al., 1975a). In a study with Charles-River pathogen-free 

mice of the CD-1 strain, 35% of the animals died at 300 mg/kg bw/day and 90% died at 600 mg/kg 

bw/day (Palmer and Lovell, 1971b). A study in New Zealand white rabbits also resulted in severe 

maternal toxicity and 85 and 100% deaths at 300 and 600 mg/kg bw/day, respectively (Palmer and 

Neuff, 1971; Palmer et al., 1975a). Finally, in a study in ICR mice, two animals died at 300 mg/kg 

bw/day (Shiobara and Imahori, 1976). In studies where maternal toxicity was observed, LOAELs 

ranged from 100-400 mg/kg bw/day, similar to the results of repeated-dose toxicity studies (section 

3.1.5) where LOAELs from oral exposures ranged from 115-750 mg/kg bw/day. 

In nine other oral exposure studies the results on offspring were similar to those of Endo et al. (1980) 

reported above, with litter effects, where observed, only occurring at maternally toxic doses (Palmer 

and Lovell 1971a; Palmer et al. 1975a; Nolen et al. 1975; Tiba et al., 1976; Palmer and Lovell 1971b; 

Takahashi et al. 1975; Shiobara and Imahori 1976; Palmer and Neuff 1971). In a drinking water 

study in rats, a dose of 600 mg/kg bw/day that produced maternal toxicity resulted in marginal 

retardation of sternebral ossification in offspring (Palmer and Lovell, 1971a). In another study in 

which maternal toxicity was observed, effects in mice and rabbit offspring included increased fetal 

loss (at 300 and 600 mg/kg bw/day), and reduced litter size and minor skeletal or visceral anomalies 

(mice at 300 mg/kg bw/day) (Palmer et al., 1975a). In a third study (mice, gavage) in which maternal 

toxicity was observed, there was delayed ossification among living fetuses and decreased body 

weights at the highest dose tested (300 mg/kg bw/day) but no increase in malformations (Shiobara 

and Imahori, 1976). In three other studies with maternal toxicity, no offspring effects were observed 

at the highest doses tested, 600 mg/kg bw/day in a gavage study in rats (Palmer et al., 1975a), 600 

mg/kg bw/day in drinking water study in mice (Palmer and Lovell, 1971b) or 400 mg/kg bw/day in a 

gavage study in mice (Takahashi et al. 1975). Three other oral studies reported no maternal or 

offspring effects at the highest doses tested, 225 mg/kg bw/day in a rat feeding study (Nolen et al. 

1975), 780 mg/kg bw/day in a second rat feeding study (Tiba et al. 1976) or 135 mg/kg bw/day in a 

rabbit feeding study (Nolen et al. 1975). 
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In addition, the three multigenerational studies reported in section 3.1.8 (Buehler et al. 1971; Palmer 

et al. 1974; Endo et al. 1980) all reported no affects on various reproductive and developmental 

parameters at doses as high as 350 mg/kg bw/day. 

Dermal Exposure 

In a representative dermal exposure study, an aqueous solution of LAS was applied to the shaved 

skin on the backs of pregnant female rats on days 2 to 15 of gestation (Palmer et al. 1975b). Doses 

were 0.03, 0.3 and 3% (0.6, 6, and 60 mg/kg bw/day). At the high dose, local irritation was 

observed resulting in a slightly lower body weight gain and hypersensitivity (increased irritability). 

No differences from the control groups were reported at any dose for number of litters, viable 

young, litter weight, fetal weight, embryonic deaths, implantations, corpora lutea, or pre- and 

postimplantation embryonic loss. No differences in major malformations or visceral and skeletal 

anomalies were observed. The resultant maternal NOAEL was 6 mg/kg bw/day and the NOAEL 

for developmental toxicity was 60 mg/kg bw/day. 

Similar results were obtained in six other dermal exposure studies, with LOAELs for maternal 

toxicity ranging from 9-1500 mg/kg bw/day (Daly et al. 1980; Palmer et al. 1975b; Sato et al. 1972; 

Imahori et al. 1976; Takahashi et al. 1975). In all cases toxicity was associated with the irritancy 

effects of LAS on skin resulting in reduced body weight as observed in the dermal repeated dose 

study (section 3.1.5). No maternal toxicity was observed at the only concentration tested (110 

mg/kg bw/day) in the mouse study of Sato et al. (1972). 

Effects on developmental parameters were observed in one study in which maternal toxicity was 

also observed (Palmer et al. 1975b). The effects included significant fetal loss and consequent 

reduction in litter size at 500 mg/kg bw/day in mice. Some fetal loss was also observed at the next 

highest dose tested (50 mg/kg bw/day) but the reduction in litter size was not statistically 

significant. Significant offspring effects were not observed in the other dermal exposure studies at 

the highest doses tested, which ranged from 90-1500 mg/kg bw/day (Table 7). 

Conclusion

LAS has been evaluated for developmental effects with rats, mice and rabbits. In oral studies, 

findings of maternal toxicity were observed at doses of 100-400 mg/kg bw/day, consistent with the 

results of oral repeated dose studies. In dermal studies, findings of maternal toxicity were observed 

at doses of 9-1500 mg/kg bw/day and were associated with the irritancy effects of LAS on skin 

resulting in reduced body weight as observed in the dermal repeated dose study. 

With regard to developmental toxicity/teratogenicity, effects such as embryo death or deformities 

and litter loss were observed only at maternally toxic doses. In two drinking water studies, delayed 

ossification in rabbits was observed at 250 mg/kg bw/day and in rats at 600 mg/kg bw/day. Mice 

and rabbits exhibited fetal loss at 300 and 600 mg/kg bw/day. Decreased litter size and minor 

skeletal/visceral anomalies were observed in mice at 300 mg/kg bw/day oral exposure. In another 

oral study, mice had delayed ossification and decreased body weight at 300 mg/kg bw/day. In a 

dermal study in mice, significant fetal loss and decreased litter size was observed at 500 mg/kg 

bw/day. 

It should be noted that several of the key studies are given a reliability score of 4. This score was 

assigned because the original reports were not available for review; however, these studies were 

evaluated and included in the IPCS review of LAS (IPCS 1996) and therefore are considered to be 

reliable for the purposes of this SIDS assessment. 
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Table 7. Results from Developmental Toxicity Studies on LAS 

Animal Route Exposure in 

Pregnancy 

NOAEL 

Maternal 

(mg/kg 

bw/day) 

NOAEL 

Fetal 

(mg/kg 

bw/day) 

Doses 

(mg/kg 

bw/day) 

Reference 

Oral Exposure 

Rat Drinking 

water 

Days 6-15 70 70 70 Endo et al. 1980 

Rat Drinking 

water 

Days 6-15 300 300 0.2, 2, 300, 

600 

Palmer & Lovell 

1971a 

Rat Gavage Days 6-15 300 600 0.2, 2, 300, 

600 

Palmer et al. 1975a 

Rat Oral feed Continuous or 

Days 6-15 

225 225 22.5, 112.5, 

225 

Nolen et al. 1975 

Rat Oral feed Days 0-20 780 780 80, 780 Tiba et al. 1976 

Mouse Drinking 

water 

Days 6-15 2 600 0.2, 2, 300, 

600 

Palmer & Lovell 

1971b 

Mouse Gavage Days 6-15 2 300 0.2, 2, 300, 

600 

Palmer et al. 1975a 

Mouse Gavage Days 0-6 or 

Days 7-13 

40 400 40, 400 Takahashi et al. 

1975 

Mouse Gavage Days 6-15 10 300 10, 100, 300 Shiobara & Imahori 

1976 

Rabbit Drinking 

water 

Days 6-18 250 

(LOAEL) 

250 

(LOAEL) 

250 Endo et al. 1980 

Rabbit Gavage Days 6-18 2 2 0.2, 2, 300, 

600 

Palmer et al. 1975a; 

Palmer and Neuff 

1971 

Rabbit Oral feed Days 2-16 135 135 22.5, 45, 135 Nolen et al. 1975 

Dermal Exposure 

Rat Dermal Days 2-15 6 60 0.6, 6, 60 Palmer et al. 1975b 

Rat Dermal Days 0-21 20 400 0.1, 2, 10, 20, 

100, 400 

Daly et al. 1980 

Mouse Dermal Days 2-13 5 50 5, 50, 500 Palmer et al. 1975 

Mouse Dermal Days 0-13 110 110 110 Sato et al. 1972 

Mouse Dermal Days 6-15 150 1500 15, 150, 1500 Imahori et al. 1976 

Mouse SC Injection Days 0-3 or 8-

11 

20 200 20, 200 Takahashi et al. 

1975 

Rabbit Dermal Days 1-16 0.9 90 0.9, 9, 90 Palmer et al. 1975b 

3.2 Initial Assessment for Human Health 

Substantial data exist for mammalian toxicity. The available data indicate that LAS exhibits slight 

acute toxicity. Oral LD50 values for rats range from 1,080 to 1,980 mg/kg bw. Oral LD50 values for 

mice are 2,160 and 2,250 mg/kg bw for males and females, respectively. The rat dermal LD50 value 

was greater than 2,000 mg/kg bw. The oral and dermal acute toxicity data for LAS generally 
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indicate low hazard potential when all studies are considered together. Acute inhalation toxicity 

data indicate that LAS is moderately toxic, with mortality occurring at respirable particle 

concentrations of 310 mg/m3

 (MMAD = 2.5 microns). 

In a series of studies on rabbits, LAS was not irritating to the skin or eyes at low concentrations 

(0.5-2.5%), moderately irritating at 5%, and more severely irritating at higher (about 50%) 

concentrations. In studies that included rinsing, eye irritation effects diminished with rinsing after 

30 seconds of exposure and were slight with rinsing after 4 seconds of exposure. In a low volume 

eye test (LVET) using a 35% LAS solution, rabbits experienced moderate irritation that was 

completely reversible by day 35. (Note that the maximum concentration of LAS is 25 percent in 

consumer products and normally less than 30 percent in commercial products.) Accidental eye 

exposure in 231 manufacturing employee incidents and 284 consumer incidents established that eye 

irritation effects of exposure during manufacturing and use of products containing LAS and other 

surfactants are moderate, transient and reversible. 

In 15 repeated dose studies with rats, mice, and monkeys exposed to LAS via oral and dermal 

routes, LOAELs ranged from 115 to 750 mg/kg bw/day. The corresponding NOAELs ranged from 

40 to 250 mg/kg bw/day. Effects commonly observed included suppressed body weight gain, 

diarrhea, increases in relative liver weight, differences in enzymatic and serum-biochemical 

parameters, and mild degeneration and desquamation of the tubular epithelium in the kidneys. 

In four well designed in vitro bacterial (Salmonella) mutagenicity studies, LAS shows no evidence 

of mutagenicity either with or without S9 metabolic activation. LAS showed no evidence of 

causing increased cell transformation in an in vitro cell transformation assay. In in vivo studies, no 

significant differences in chromosome aberrations were seen when mice were given either oral 

doses up to 800 mg/kg bw/day or dietary doses up to 1170 mg/kg bw/day. In a mouse micronucleus 

study, LAS did not induce a clastogenic effect. Rats given dietary doses up to 450 mg/kg bw/day 

also showed no significant differences in chromosome aberrations. Collectively, these data support 

that LAS is not genotoxic. 

The highest dose tested in four carcinogenicity studies with rats was 300 mg/kg bw/day. In the 

most documented study, rats were administered up to 250 mg LAS/kg body weight/day in the diet 

for two years. Results of this study indicate no gross or histopathological evidence of a 

carcinogenic effect. No evidence of tumorigenesis was observed in any of the carcinogenicity 

studies. While the quality and focus of the studies precludes a definitive assessment, the results of 

the genetic toxicology and rodent bioassay studies collectively provide strong weight-of-evidence 

support that LAS is not genotoxic and is not a rodent carcinogen. 

Similarly, no evidence of reproductive or fertility effects was observed in any of the three available 

reproductive toxicity studies in which rats were given dietary doses over three to four generations. 

NOAELs from these reproductive studies ranged from 70 to 350 mg/kg bw/day, which were the 

highest doses tested. In 17 developmental toxicity studies, effects such as embryo death or 

deformities, and litter loss were most often observed only at maternally toxic doses and were 

associated with the irritation effects of LAS on skin or the gastrointestinal tract. No decreases in 

litter size, no changes in litter parameters, no malformations or significant differences in skeletal 

defects were observed at oral doses up to 780 mg/kg bw/day in rats and at dermal doses of 500 

mg/kg bw/day in mice and 90 mg/kg bw/day in rabbits. 

All of the studies included in the dossier are considered reliable, but all with limitations. The 

results are consistent with each other and these data are used in a weight-of-evidence approach. 

Based on these considerations, the highest NOAEL value below the lowest LOAEL from all of the 

mammalian toxicity studies is the most appropriate. Therefore, the NOAEL is 85 mg/kg bw/day. 

This value comes from a rat drinking water, 9-month repeated dose toxicity study. The lowest 
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LOAEL (115 mg/kg/day) was associated with increased weight of the cecum and slight 

degeneration of the renal tubules. 

Current LAS production is approximately 390,000 metric tons in the North America, 400,000 

metric tons in Europe, and 85,000 metric tons in Japan. Global production was 2.6 million metric 

tons in 1995. In the production phase, manufacturing processes have been designed to maximize 

production yield and minimize potential releases. Worker exposure is possible during the detergent 

formulation stage by inhalation of powders or dermal contact of powders and liquids. Good 

manufacturing design practices (e.g., enclosed production in agglomeration processes, exhaust 

ventilation, dust collection) and personal protective equipment (e.g., protective clothing, eyewear, 

and gloves) in place at facilities that manufacture liquid and dry (granular/powder) materials are 

anticipated to mitigate worker exposure to LAS. Any LAS that is not incorporated into a product is 

captured by dust-handling equipment for recycling back into the production process. A limited 

amount of LAS in aqueous solution may be released as a dilute solution from washing and rinsing 

operations in the manufacturing process and is discharged to wastewater treatment. Incidental 

quantities of the dry (granular/powder) product (e.g., from floor sweepings) may be disposed in 

landfills. 

Labelling of consumer products containing LAS and other surfactants include warnings of the 

potential for eye irritation and first aid instructions to rinse with water. 

Data suggest that inhalation of LAS products during use will be low. Spray products containing 

LAS are designed to produce the large particle sizes needed for efficient delivery of the spray to the 

surface being cleaned. In laboratory simulations with six spray nozzles representing those used in 

spray cleaning products, less than 0.1% of the total volume sprayed consists of respirable particles 

(particles under 10 microns in diameter) and air concentrations in the breathing zone are in the 0.13-

0.72 mg/m3

 range. Inhalation of detergent dusts during washing processes, modeled by HERA 

(2004), was 10-fold lower than inhalation of aerosols from cleaning product sprays. This estimate 

is based on a published study reporting an average of 0.27 μg dust per cup of product used for 

machine laundering. This is a conservative (protective) estimate as exposure from modern 

compact/granular detergent formulations produced in agglomeration processes, which produce 

larger particle sizes, would be expected to be much less. Based on these data, it is expected that 

exposures to respirable particles from inhalation are low. 

4 HAZARDS TO THE ENVIRONMENT 

4.1 Aquatic Effects 

The aquatic toxicity of LAS has been extensively studied, and several comprehensive reviews have 

been prepared (e.g., Arthur D. Little (SDA) 1991; BKH 1993; ERASM 2000; IPCS 1996; van de 

Plassche et al. 1999). The data cover a wide range of taxonomic groups and exhibit a predictable 

degree of intra- and inter-species variability attributable to differences in test design, differences in 

species sensitivity, and the use of different chain length mixtures of LAS. 

Factors Affecting Toxicity 

Aquatic toxicity is greater for individual homologues of LAS with longer carbon chains and would 

therefore be expected to be greater for commercial LAS products with longer average chain lengths. 

Although the 48 hour study was shorter than normal and less than the standard number of fish were 

used, the Kimerle and Swisher (1977) study clearly demonstrates the increase in toxicity to fathead 
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minnows and to Daphnia magna with increasing homologue chain length. These data are shown in 

Table 8. 

Table 8. Aquatic Toxicity for Individual LAS Homologues1

 48-hour LC50 (mg/L) 

D. magna 

(Dossier, section 4.2Af) 

Fathead minnow 

(Dossier, section 4.1r) 

Individual LAS Homologues 

C10 12.3 43.0 

C11 5.7 16.0 

C12 3.5 4.7 

C13 2.0 0.4 

C14 0.7 0.4 

1

 Reliability of Study = (2) 

As discussed in section 2.2.6, the longer alkyl chain homologues biodegrade faster (Bock and 

Wickbold, 1966). Toxicity of the biodegradation intermediates is significantly less than the parent 

LAS. Acute toxicity tests conducted on LAS degradation intermediates (i.e., SPCs) yielded 48-hour 

LC50 values >1000 mg/L for fathead minnows and D. magna using the same procedures as for the 

data reported in the above table (Kimerle and Swisher 1977). 

The trend of increasing toxicity with increasing alkyl chain length has also been demonstrated with 

algae. In one study, three different LAS materials with average chain lengths of C11, C11.6, and C13

were tested in accordance with the OECD 201 protocol under GLP conditions (Verge and Moreno 

1996a, dossier section 4.3d,e). The resultant EC50 values were 240, 163, and 54 mg/L, respectively, 

for the three materials. Similarly, the authors tested five pure homologue cuts and determined the 

EC50 values to be 270, 111, 48, 30, and 18 mg/L for the pure C10, C11, C12, C13, and C14, 

respectively. 

Qualitative Structure-Activity Relationships (QSARs) have been developed for LAS and other 

surfactants (Roberts 2004). These QSARs are based on correlations to the log Kow and supported 

by considerable experimental data. Although it is extremely difficult to accurately measure log 

Kows for surfactants because of their strong preference for the oil-water interface, log Kows may be 

reliably calculated using the Leo and Hansch method as modified Roberts. This method takes into 

account all the structural elements of the surfactant molecule including for LAS, the alkyl chain 

length and the position of attachment of the sulfophenyl group to the alkyl chain. For LAS category 

materials (and many other surfactants), the alkyl chain length is the major structural element that 

varies and thus the major factor causing the log Kow for LAS to vary. The QSAR for LAS is 

described more fully in Annex 3, where it is used to calculate chronic NOEC values for C11.6 LAS. 

Acute Toxicity Test Results

Freshwater Fish 

LAS toxicity has been evaluated on a variety of freshwater fish species in many studies. Van de 

Plassche et al. (1999) reviewed the acute fish data compiled by BKH (1993) for LAS and related 

materials, including many materials with average alkyl chain lengths outside the range of current 

commercial LAS (section 1.1), and for alkyl chain homologs from C10 to C14 (original studies not 

reviewed). Van de Plassche et al. commented that the range of LC50 values was very large due to 
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the range of materials tested (including many materials not representative of commercial LAS) and 

the differences in test design (not necessarily following standard guidelines). Consequently, the 

range of LC50 values for fish presented by Van d Plassche et al. was only provided for one species 

(Pimephales promelas, 0.40-100 mg/L) as an example of the wide ranges found. These values 

include mixtures of chemicals in addition to commercial LAS products. It is unclear which values 

within the range refer to the commercial LAS products and the individual records were not 

available for validation. 

Van de Plassche et al. (1999) did calculate the geometric mean values for seven species of fish, as 

shown in Table 9 below, and found the interspecies variation decreases considerably when the 

geometric mean value per species is calculated. This comparison indicates that the large variation 

found (e.g., P. promelas LC50 values ranged from 0.4-100 mg/L; geometric mean = 3.2 mg/L) is 

due primarily to the wide range of materials tested and differences in test designs. 

Table 9. Geometric Mean Fish LC50 Toxicity Results1

Species Geometric Mean (Range) 

LC50 (mg/L) Number of Records 

Lepomis macrochirus (bluegill sunfish, dossier 

section 4.1c) 3.0 88 

Pimephales promelas (fathead minnow, 

dossier section 4.1d)

3.2 

(0.4-100 mg/L) 

35 

Leusiscus idus melanotus (golden orfe, dossier 

section 4.1e) 2.9 11 

Carassius auratus (goldfish, dossier section 

4.1f) 9.5 46 

Oncorhynchus mykiss (rainbow trout, dossier 

section 4.1f) 3.0 10 

Oryzias latipes (medaka, dossier section 4.1f) 13 5 

Poecilia reticulata (guppy, dossier section 4.1f) 3.8 9 

1

Reliability of Studies = (4); Original Data Not Reviewed 

HERA (2004) conducted an extensive search of the data previously compiled by BKH (1993) and 

the published and unpublished literature since this data compilation for studies on commercial LAS 

and on species for which standardized test methodologies are available. As described in Appendix 

2, a total of 18 fish studies were identified. Of these 11 studies were found to have been conducted 

using currently relevant LAS (C11.6-C11.8) and valid test methods. LC50 values ranged from 1.67-7.7 

mg/L with no values below 1 mg/L. A robust summary for the study representing the lowest value 

for fish (critical study) was prepared and the study reference is provided in Table 10. 
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Table 10. Acute Aquatic Toxicity Results (lowest value for each taxon) 1

Taxon LC50/EC50/IC50 (mg/L) Reference 

Fish (Lepomis macrochirus), LC50

(dossier, section 4.1a) [96 hr. exposure] 1.67 Lewis and Perry 1981 

Daphnia magna, EC50 (dossier, section 

4.2Aa) [48 hr. exposure] 1.62 Hooftman and van DrongelenSevenhuijsen 1990 

Algae (Selenastrum capricornutum), 

IC50 (dossier, section 4.3a) [96 hr. 

exposure] 

29.0 Lewis 1986; Lewis and Hamm 

1986 

1

The reliability of studies = (2) 

Freshwater Invertebrates 

LAS toxicity has also been evaluated on a variety of freshwater invertebrate species in many 

studies. Van de Plassche et al. (1999) reviewed the acute invertebrate data compiled by BKH 

(1993) for LAS and related materials, including many materials with average alkyl chain lengths 

outside the range of current commercial LAS (section 1.1), and for alkyl chain homologs from C10

to C14. Similar to the results with fish, the range of invertebrate EC50 values was very large due to 

the range of materials tested (including many materials not representative of commercial LAS) and 

the differences in test design (not necessarily following standard guidelines). The range of EC50

values was only provided for one invertebrate species (Daphnia magna, 0.26-55 mg/L). These 

values include chemicals in addition to commercial LAS products. It is unclear which values within 

the range refer to commercial LAS products and the individual records were not available for 

validation. 

Van de Plassche et al. (1999) also calculated the geometric mean value for Daphnia magna and 

other aquatic invertebrates. The geometric mean EC50 for Daphnia magna based on 139 records 

was determined to be 4.7 mg/L (dossier, section 4.2Ac). The geometric mean EC50 values for 

Gammarus pulex, Mysidopsis bahia, and Panaeus duorarum were 6.2 mg/L (25 records), 1.7 mg/L 

(6 records), and 49 mg/L (5 records), respectively (dossier, section 4.2Ba). Because this is a review 

article and the individual studies were not reviewed independently, the reliability of these studies is 

not assignable. Lewis and Surprenant (1983) also reported an LC50 of 16 mg/L for the nematode 

Rhabditis sp. for C12 LAS (dossier, section 4.2Bf; reliability = 2). 

The HERA search (HERA 2004) also found 20 daphnid studies on commercial LAS, of which 11 

studies were on currently relevant LAS (C11.6-C11.8) and followed standardized test methods (Annex 

2). EC50 values on Daphnia magna ranged from 1.62 to 9.3 mg/L. A robust summary for the study 

representing the lowest value has been prepared and the study is referenced in Table 10 above. 

Freshwater algae 

LAS toxicity has also been evaluated on a variety of freshwater algae species although van de 

Plassche et al. (1999) did not provide geometric mean or range data on acute algae data. 

The HERA search (HERA 2004) found 13 algae studies on commercial LAS, of which 5 studies 

were on currently relevant LAS (C11.6-C11.8) and followed standardized test methods (Annex 2). 

The range of ErC50 values on algae ranged from 29-163 mg/L. A robust summary for the study 

representing the lowest value has been prepared and the study is referenced in Table 10 above. 

Marine Species 

Acute aquatic toxicity data for marine species have been summarized by van de Plassche et al. 

(1999). Geometric mean EC50 values were 6.2 mg/L (25 records), 1.7 mg/L (6 records), and 49 
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UNEP PUBLICATIONS 39

mg/L (5 records) for Gammarus pulex (amphipod), Mysidopsis bahia (mysid), and Panaeus 

duorarum (pink shrimp), respectively (dossier, section 4.2Ba). Temara et al. (2001) also 

summarized acute aquatic toxicity data, as shown in Table 11. 

Table 11. Aquatic Toxicity for Marine Species1,2 

Taxon 

Geometric Mean LC50

(mg/L) Alkyl Chain Length Number of Records 

All spp.3 4.36 (SD = 0.79) C11.7-12.0 36 

Crustacea 17.0 (SD=0.68) C11.7-12.0 14 

Fish 1.58 (SD = 0.16) C11.7-12.0 6 

1 From Dossier 4.1g, 4.2Bb 

2 Reliability of Studies = (4); Original Data Not Reviewed 

3

 Data from fish, crustacea, algae and other species. 

Chronic Toxicity Test Results

Freshwater Species 

Table 12 in the SIAR includes all available, reliable chronic freshwater NOEC values obtained in 

studies following guideline exposure periods (28-30 days for fish, 21 days for invertebrates and 3-4 

days for algae). These studies result in the following NOEC values: fish NOEC = 1 mg/L (two 

studies, two species); Daphnia, NOEC = 1.18-3.25 mg/L (six values, two studies, one with 5 diets); 

algae, NOEC = 0.4-18 mg/L (four studies, two species). 

Table 12 - Chronic NOEC Values for Freshwater Species Following Guideline 

Exposure Periods1

 

Species, Reference (Reliability) Endpoint (Exposure Period) NOEC 

(mg/L) 

LAS Alkyl Chain 

Length 

Fish (28-30 day exposure period) 

Lepomis macrochirus, dossier 4.5.1m (2) Juvenile Growth2 (28 d) 1.0 11.6 

Pimephales promelas, dossier 4.5.1b (2) Fry Survival (30 d) 1 12.3 

Invertebrates (21 day exposure period) 

Daphnia magna, dossier 4.5.2c (2) Reproduction (21 d) 1.18 11.8 

Daphnia magna, dossier 4.5.2e (2) Reproduction (21 d) 1.25-3.753 11.8 

Algae (3-4 day exposure period) 

Scenedesmus subspicatus, dossier 4.3e (2) Population Growth Rate (3 d) 18 12.0 

Scenedesmus subspicatus, dossier 4.3f (1) Population Growth Rate (3 d) 2.4 11.6 

Scenedesmus subspicatus, dossier 4.3g (1) Population Growth Rate (3 d) 0.4 11.6 

Selenastrum capricornutum, dossier 4.3a 

(2) Population Growth Rate (4 d) 0.5 11.8 

1

Reliability of Studies = (2) or (1) 

2

 Most sensitive endpoint. 

3

 Range of NOECs of 5 diets. 

The chronic toxicity to freshwater aquatic organisms of commercial LAS with C10-13 alkyl chains 

and average carbon lengths close to C11.6 has been reviewed by van de Plassche et al. (1999) and the 
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UNEP PUBLICATIONS 40

geometric mean NOEC values, normalized to C11.6 LAS, from this review are provided in Table 

12A. These values are based on the earlier data compilation of BKH (1993) but the archive of 

studies for this data compilation is no longer available and a new compilation was undertaken. The 

available freshwater chronic toxicity studies were retrieved and robust summaries prepared on all 

the available studies. The reliable chronic studies are shown in Table 12A. Additional studies in 

the dossier were not included in the table either because the duration of the test was too short for a 

reliable chronic study or because the reliability of the study could not be assessed. Available 

NOEC values from individual studies ranged from 0.25 to 54.3 mg/L. The endpoints affected 

included behavior, growth, mobility, mortality, and reproduction, depending on the species tested. 

Table 12A. Chronic Aquatic Toxicity for Freshwater Species* 

Species, Reference 

(Reliability) 

Endpoint 

(Exposure 

Period) 

Available 

NOEC 

(mg/L) 

LAS Alkyl 

Chain 

Length 

Available 

NOEC 

Normalized to 

C11.6 LAS1

Van de Plassche et al. 

(1999) Geometric Mean 

NOEC (mg/L), 

Normalized to C11.6 

LAS, (range2), [Number 

Studies] 

Fish 

Brachydanio rerio4 2.3 [1] 

Lepomis macrochirus, 

dossier 4.5.1m (2)

Juvenile 

Growth8

 (28 d) 1.0 11.6 1.0 --3

Oncorhynchus 

mykiss4 0.34 (0.19-0.89) [7] 

Pimephales promelas, 

dossier 4.5.1b (2) 

Fry Survival 

(30 d) 1 12.3 1.87 

Pimephales promelas, 

dossier 4.5.1j (2) 

Fry Survival 

(196 d) 0.63 12.0 0.9 

Pimephales promelas, 

geometric mean 1.3 0.87 (0.3-2) [14] 

Poecilia reticulata4 3.2 [1] 

Tilapia mossambica, 

dossier 4.5.1e (2) 

Reproduction 

(90 d) 0.25 N/A5

 0.25 0.25 [1] 

Aquatic Invertebrates 

Ceriodaphnia sp., 

dossier 4.5.2b (2) 

Reproduction 

(7 d) 0.79

 11.8 0.84 3.2 [1] 

Chironomus riparius, 

dossier 4.5.2o (2) 

Emergence (24 

d) 2.4 11.8 2.87 2.8 [1] 

Daphnia magna, 

dossier 4.5.2c (2) 

Reproduction 

(21 d) 1.18 11.8 1.41 

Daphnia magna, 

dossier 4.5.2e (2) 

Reproduction 

(21 d) 1.9910 11.8 2.38 

Daphnia magna, 

geometric mean 1.83 1.4 (0.3-10) [12] 

Paratanytarsus 

parthenogenica, 

dossier 4.5.2h (2)

Survival & 

Population 

Size (28 d) 

3.4 N/A5

 3.4 3.4 [1] 

Algae 

Chlamydomonas 

reinhardi4 12 [1] 
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Chlorella kessleri4 3.5[1] 

Microcystis

aeruginosa, dossier 

4.3s (2) 

Population 

Growth Rate 

(4 d) 

0.36

 11.6 0.3 0.80 (0.3-10.77) [4] 

Plectonema 

boryanum4 15 [1] 

Scenedesmus 

subspicatus, dossier 

4.3d (2) 

Population 

Growth Rate 

(3 d) 

54.36

 11.6 54.3 

Scenedesmus 

subspicatus, dossier 

4.3e (2) 

Population 

Growth Rate 

(3 d) 

18 12.0 26 

Scenedesmus 

subspicatus, dossier 

4.3f (1) 

Population 

Growth Rate 

(3 d) 

2.4 11.6 2.4 

Scenedesmus 

subspicatus, dossier 

4.3g (1) 

Population 

Growth Rate 

(3 d) 

0.4 11.6 0.4 

Scenedesmus 

subspicatus, 

geometric mean 

 6.1 7.7 (0.8-1057

) [4] 

Selenastrum 

capricronutum, 

dossier 4.3a (2)

Population 

Growth Rate 

(4 d) 

0.5 11.8 0.58 3.8 (1-397

) [9] 

Higher Plants 

Elodea canadensis, 

dossier 4.3o (2) 

Growth, 

Productivity 

(28 d) 

4 11.6 4 --3

Lemna minor, dossier 

4.3p (2) 

Frond Count 

(7 d) 0.96

 11.8 1.1 --3

*Reliability of Studies = (2) or (1), except for Van de Plassche et al. (1999), where Reliability = (4), Original 

Data Not Reviewed 

1

 The normalization procedure is described in SIAR Annex 3. 

2

 Feijtel & van de Plassche, 1995. 

3

 Not reviewed by van de Plassche et al. 1999. 

4

 No valid chronic study identified. 

5 Not available. 

6

 EC50 value divided by 3; as documented in Annex 3, the average EC50/NOEC ratio for LAS is 3. 7

 Ranges include EC50/3. 8

 Most sensitive endpoint. 

9

 Geometric mean of trout chow/algae NOEC (0.5 mg/L) and yeast diet EC10 (0.99 mg/L). 10 Geometric mean of 5 diets considered by the authors of the study to be equivalent to 5 replications of the same 

diet. 

Table 12A also provides the available NOEC values normalized to C11.6 LAS by the QSAR 

procedures used by van de Plassche et al. (1999) and described in detail in Annex 3. Geometric 

mean normalized NOEC values are provided for species (P. promelas, D. magna and S. 

subspicatus) for which multiple studies are available. These normalized NOEC values range from 

0.25 to 6.1 mg/L for the 12 species for which we were able to document reliable values. The 

similarity of these values, as shown in Table 12A, to those of van de Plassche et al. (1999) supports 

the validity of the BKH (1993) data compilation and the van de Plassche et al. (1999) assessment of 

the data despite the fact that not all of the studies cited by these authors could be retrieved and 

validated. 
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Van de Plassche et al. (1999) used statistical methods to estimate the lowest 5% of the NOEC 

distribution, the HC5. The HC5 value calculated by van de Plassche et al., from the NOEC data 

shown in Table 12A, was 0.32 mg/L. This value is based on a fit of the data to a log-normal 

distribution. As described in Annex 3, an improved estimate can be obtained by comparing the 

goodness of fit of various distributions. The best distribution to the van de Plassche data was found 

with the log-logistic distribution, which gave an HC5 value of 0.36 mg/L (Annex 3). Applying 

these same methods to the available NOEC data, normalized to C11.6 LAS (Table 12A), gave an HC5

value of 0.24 mg/L (Annex 3). Because these values are based on NOEC data from 12 or more 

species of fish, algae, several groups of invertebrates, and higher plants (for the available data), 

these values are all considered to be valid estimates of the HC5 for LAS. Based on goodness of fit, 

the best HC5 values are 0.24 mg/L for the available NOEC data and 0.36 mg/L for the van de 

Plassche et al. (1999) data. 

Marine Species 

Chronic aquatic toxicity data are available for marine species and have been summarized by van de 

Plassche et al. (1999) and Temara et al. (2001). Because these are review articles the reliability of 

the individual studies could not be independently assessed. Geometric mean results are shown in 

Table 13. 

Table 13. Chronic Aquatic Toxicity Data for Marine Species (dossier 4.5.2t)1 

Genus (and species) Geometric mean NOEC (mg/L) 

Fish 

Limanda (yokohamae)* 0.05 

Aquatic Invertebrates 

Arbacia 0.45 

Arcatia 0.30 

Asterias 0.35 

Botrylloides 1.94 

Botryllus 0.75 

Chaetopterus 0.45 

Crassostrea (virginica)* 0.025 

Crassostrea 0.04 

Molgula 0.90 

Mysidopsis (bahia)* 0.12 

Mysidopsis 0.20 

Mytilus (edulis)* 0.025 

Mytilus 0.04 

Spisula 0.80 

Algae 

Dunaliella 0.11 

Laminaria 5.00 

1

Reliability of Studies = (4); Original Data Not Reviewed 

*Normalized to C11.6 LAS (van de Plassche et al. 1999); all others are for LAS with average alkyl chain lengths of 

11.6-12.0 (Temara et al. 2001) 
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Toxicity to Microorganisms

Three LAS mixtures (average chain lengths of C11, C11.6 and C13) and five pure homologues 

were used to evaluate inhibition to activated sludge using OECD Guideline 209 (Verge and Moreno 

1996b, dossier section 4.4a,b). Results showed EC50 values of 760, 550 and 650 mg/L for the C11, 

C11.6, and C13 commercial materials, respectively, and 1042-1200, 740-782, 500-723, 700-795, 

and 900-1045 mg/L for the C10, C11, C12, C13, and C14 pure homologues, respectively. In all of 

these studies, an extended contact time of 3 hours (instead of the standard 15 minutes) was used to 

better simulate the normal residence time in wastewater treatment plants. An older study using the 

standard 15-minute exposure reported EC50 values of 107-152 mg/L for a commercial LAS sample 

(dossier 4.4c; reliability not assignable). Studies with C11.6/C11.8 LAS and the bacterium 

Pseudomonas putida reported EC50 values of 350 mg/L (30-min. exposure, dossier 4.4e), 150 mg/L 

(16-hr exposure, dossier 4.4f) and 60.9-63.5 mg/L (18-hr. exposure, dossier 4.4d) and 

EC0/EC10/NOEC values of 64 and 250 mg/L (30 min. exposures, dossier 4.4e,g), 30 and 50 mg/L 

(16-hr. exposure, dossier 4.4f,h) and 52.7-56.6 (18-hr. exposure, dossier 4.4d). While there is 

variability in the values, the data are consistent in showing LAS toxicity to activated sludge or a 

bacterium only at LAS concentrations considerably above those observed in the aquatic 

environment. 

Normal operation of an activated sludge digester was observed even in the presence of high and 

atypical concentrations of LAS (30 g/kg dry matter) in anaerobic sludge indicating that the 

microbial population present was not inhibited (Berna et al., 1989, dossier 4.4i). The treatment 

plant operational records were not directly available for review, so these conclusions are based on 

the evaluation of Berna et al. (1989). Sanz et al. (1999, dossier 3.5p) determined that 

concentrations of LAS usually found in anaerobic digesters are an order of magnitude lower than 

concentrations that may be inhibitory to anaerobic microbial populations (40-150 mg C11.54 

LAS/L). Based on the sludge partition coefficient for C11.6 LAS (dossier 3.3.1a) of 2500 L/kg, 

aqueous phase concentrations inhibitory to anaerobic microbial populations (40-150 mg/L) would 

require LAS levels in sludge of 100-375 g/kg, fully supportive of the results of Berna et al (1989) 

above showing no inhibition of anaerobic microbial populations in activated sludge digesters at 

LAS concentrations of 30 g/kg dw sludge. 

Sediment Toxicity Test Results

Several studies have investigated the toxicity to organisms exposed to LAS in the sediment, as 

summarized in Table 14. Midge larvae (Chironomus riparius) were exposed for 24 days to natural 

stream sediment spiked with commercial LAS with an average alkyl chain length C11.8 (Pittinger et 

al. 1989). The resultant LOEC was 993 mg/kg and the NOEC 319 mg/kg, based on emergence 

success. A fresh water bivalve mollusk, Anodonta cygnea, was exposed to commercial LAS sorbed 

to natural pond sediment by repeated additions for 80 days (Bressan et al. 1989). All animals 

survived and were actively filter-feeding at sediment concentrations measured to be 750 mg/kg at 

the beginning of the test and 200 mg/kg at the end of the test. Similarly, a tubificid, Branchiura 

sowerbyi, was exposed for 220 days to sediment spiked with an undefined LAS (Casellato et al. 

1992). No effects were observed at mean measured concentrations that were initially 26 mg/kg and 

decreased to 7.18 mg/kg by the end of the study. While the absence of reported toxicity is 

reassuring, it appears that the range of exposure concentrations was too low to derive a useful 

NOEC value. In addition, the reliability of the study could not be assessed so it is not included in 

Table 14. According to Marin et al. (1994), no effects were observed in the marine mussel, M. 

galloprovinciallis, at 132 mg/kg (initial measured concentration) of C11.6 LAS. The LAS 

concentration decreased by 90% by the end of the exposure to 7.85 mg/kg, which is the value 

reported as the NOEC in Table 14. Most recently, GLP studies have been conducted with 

Lumbriculus variegates (an oligochaete worm) and Caenorhabditis elegans (a nematode worm) to 

finalize the effects assessment of sediment associated C11.4 LAS (Comber et al. 2004). After 28 
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days of exposure to artificial sediment spiked with radiolabeled LAS, the resultant survival, 

reproduction and growth NOEC for L. variegates was 81 mg/kg based on the average 

concentrations measured at 0 and 28 days. For C. elegans, the NOEC was 100 mg/kg after 3 days 

exposure to artificial sediments spiked with non-radiolabeled LAS based on effects on egg 

production. 

Table 14. Results of Sediment Exposures1

Species Endpoint Test Duration 

(days) 

NOEC 

(mg/kg) Reference (Reliability) 

Freshwater 

Chironomus riparius Emergence 24 319 Pittinger et al. 1989, dossier 

4.5.2v 

Anodonta cygnea Survival, 

Behavior 80 ≥200* Bressan et al. 1989, dossier 4.5.2p 

Lumbriculus variegatus Reproduction, 

Growth 28 81 Comber et al. 2004, dossier 4.5.2r 

Caenorhabditis elegans Fertility, Egg 

Production 3 100 Comber et al. 2004, dossier 4.5.2s 

Marine 

Mytilus galloprovincialis 

Survival, 

Physiological 

Response 

7 ≥7.85** Marin et al. 1994, dossier 

4.5.2u 

1

 Reliability of Studies = (2) 

* The measured concentration in the test chamber was 750 mg/kg at test initiation and 200 mg/kg at test 

completion (highest concentration tested). 

** The measured concentration in the test chamber was 132 mg/kg at test initiation and 7.85 mg/kg at test 

completion (highest concentration tested). 

Model Ecosystem Test Results

A variety of model ecosystem and mesocosm studies have been conducted on LAS. Many of these 

studies have been evaluated and summarized in two recent review papers (van de Plassche et al. 

1999; Belanger et al. 2002). NOEC values for standing (lentic) and flowing (lotic) water model 

ecosystems range from about 0.12 to 9.8 mg/L (Table 15). The lowest NOEC value (0.12 mg/L) 

was observed in an artificial stream study (Tattersfield et al., 1995, 1996) in which river water was 

seeded from field collections and a hydrocyclone used to prevent colonization of biota throughout 

the study. Drift therefore comprised only emigration and not immigration. This is an ecologically 

restrictive study design that ignores the importance of recovery vectors present in natural systems. 

In addition, the reliability could not be adequately assessed so this study is not included in Table 15. 

An integrated model stream ecosystem (Experimental Stream Facility, ESF) without these design 

limitations was used to test a C12LAS homologue with a high content (35.7%) of its most 

hydrophobic and toxic 2-phenyl isomer (Belanger et al. 2002). The 56-day ESF study included a 

representative community encompassing over 250 taxa and resulted in an NOEC value of 0.27 

mg/L. The Belanger et al. (2002) review of the mesocosm studies, including the Tattersfield et al. 

study, concluded that a NOEC of 0.27 mg/L for C12 LAS (0.37 mg/L if normalized to C11.6 LAS) 

was the most reliable, defensible, and robust value for the aquatic ecosystem. This value is based 

on model stream ecosystem studies of over 250 species, and is consistent with the single-species 

chronic freshwater data (Table 12A), and the resultant HC5 values (0.24-0.36 mg/L for C11.6 LAS). 
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Table 15. Results of Model Ecosystem Studies1

Type of 

Ecosystem 

Avg. 

Alkyl 

Chain 

Length 

Exposure 

Duration 

Most Sensitive Endpoint 

(Species) 

NOEC 

(mg/L) 

Reference (Reliability) 

Experimental 

Stream 

C12 56 days Increased drift, reduced 

benthic abundance 

(Invertebrates) 

0.27 Belanger et al. 2002, 

dossier 4.7a (1) 

Experimental 

Stream 

C11.9 45 days No effects observed 

(Periphyton, detritus, 

invertebrates, snails, 

amphipods and fish) 

>0.36 Fairchild et al. 1993, 

dossier 4.7f (2) 

Outdoor Ponds C12 56 days Reduced egg production 

(Cyclopedia) 

3.5 Huber 1989; Huber et al. 

1987, dossier 4.7 g (2) 

Aquaria with 

sediment and 

activated sludge 

effluent 

C11.9 28 days Microbial function 0.5 Larson and Maki 1982, 

dossier 4.7h (2) 

Aquaria with 

sediment and 

activated sludge 

effluent 

C11.9 28 days Growth (Bluegill sunfish) 1.0 Maki 1981, dossier 4.7i 

(2) 

In Situ River C11.9 21 days Photosynthesis inhibition 

(phytoplankton) 

9.8 Lewis et al. 1993, 

dossier 4.7j (2) 

Bottles filled with 

lake water 

C11.8 

C13.3

3 hours/ 

month for 6 

months 

Photosynthesis inhibition 

(phytoplankton) 

3.4* 

1.9* 

Lewis and Hamm 1986, 

dossier 4.7k (2) 

1

Reliability of Studies = (2) or (1) 

* EC50 values

4.2 Terrestrial Effects 

A large amount of ecotoxicity data are available for terrestrial organisms (e.g., Carlsen et al. 2002). 

Many of the studies, both laboratory and field, have been conducted recently in Denmark on soil 

organisms including plants, soil invertebrates, and microorganisms (Jensen and Krogh 1999; Jensen 

et al. 2001; Holmstrup and Krogh 2001; Elsgaard et al. 2001a,b; Brandt et al., 2003).

Terrestrial Toxicity – Soil Invertebrates 

The data from studies evaluating the effects of LAS on soil dwelling organisms have recently been 

summarized in Jensen et al. (2001). However, the reliability of the individual studies could not be 

directly assessed so they are not included in Table 16. Additional information is available from 

other investigations of LAS toxicity on terrestrial invertebrates with test durations ranging from 14 

days to 6 weeks (Holmstrup and Krogh 2001; Mieure et al. 1990). These additional data are 

summarized in Table 16. All studies used natural agricultural soil, with the exception of Mieure et 

al. (1990), who used artificial soil. In all studies, C11.5/C11.6 LAS was added as aqueous solutions 

and not associated with sludge, which would be the normal route of exposure for agricultural soil. 

The bioavailability of LAS is greatly affected by interaction with sludge (Elsgaard et al. 2001a, b) 

and the toxicity in Table 16 below may or may not reflect exposure to free LAS in soil interstitial 

water. It is not known whether the data appropriately account for bioavailability in sludge-amended 

soils. (See Dossier section 4.6.1 for more information.)
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Table 16. Results of LAS Exposures on Soil Invertebrates (in mg/kg dry weight)1 

Species 

(test duration) Endpoint NOEC LOEC L/EC10 L/EC50

Reference 

(Reliability) 

Aporrectodea 

caliginosa 

(28 d) 

Adult Survival 

Juvenile Survival 

Juvenile Growth 

278 

>397 

278 

793 

>397 

397 

329 

>397 

105 

535 

>397 

354 

Holmstrup and 

Krogh 2001, dossier 

4.6.1b (2) 

Aporrectodea 

longa

(28 d) 

Adult Survival 

Juvenile Survival 

Juvenile Growth 

278 

397 

79 

793 

793 

278 

329 

296 

84 

535 

517 

349 

Holmstrup and 

Krogh 2001, dossier 

4.6.1b (2) 

Enchytraeus 

albidus

(6 wks) 

Adult survival 

Reproduction 

<750 

750 

750 

1500 

511 

447 

1400 

1143 

Gejlsbjerg et al., 

2001; dossier 4.6.1f 

(2) 

Enchytraeus 

albidus

(21 d) 

Adult Survival 

Reproduction 

198 

20 

397 

40 

194 

6 

430 

41 

Holmstrup and 

Krogh 2001, dossier 

4.6.1b (1) 

Eisenia foetida

(14 d) Body Weight 250 500 >1000 Mieure et al. 1990, 

dossier 4.6.1c (2) 

Folsomia candida

(4 wks) 

Adult survival 

Reproduction 

1000 

500 

2500 

1000 

750 

480 

1338 

1143 

Gejlsbjerg et al., 

2001; dossier 4.6.1f 

(2) 

Folsomia 

fimetaria

(21 d) 

Adult Survival 

Reproduction 

>793 

278 

>793 

278 

>793 

85 

>793 

424 

Holmstrup and 

Krogh 2001, dossier 

4.6.1b (1) 

Folsomia 

fimetaria

(21 d) 

Adult survival 

Juvenile survival 

Reproductive output 

Juvenile growth 

Molting frequency 

>1000 

500 

500 

<200 

<300 

>1000 

700 

1000 

200 

300 

>1000 

196 

147 

163 

185 

>1000 

570 

737 

896 

923 

Holmstrup and 

Krogh, 1996, dossier 

4.6.1e (2) 

Hypoaspis 

aculeifer

(21 d) 

Adult Survival 

Reproduction 

>793 

278 

>793 

793 

>793 

82 

>793 

236 

Holmstrup and 

Krogh 2001, dossier 

4.6.1b (2) 

Hypogastrura 

assimilis

(21 d) 

Reproduction 79 278 99 421 

Holmstrup and 

Krogh 2001, dossier 

4.6.1b (1) 

Lumbricus 

terrestris

(14 d) 

Body Weight/ Burrowing 667 1333 >1333 Mieure et al. 1990, 

dossier 4.6.1d (2) 

1

Reliability of Studies = (2) or (1) 

Terrestrial Toxicity – Plants 

Several studies have been conducted in which terrestrial plants have been exposed to LAS-spiked 

soils. These studies are summarized in Table 17 and presented in Dossier section 4.6.2. Windeat 

(1987) evaluated the effect of C11 LAS on three crop species (sorghum, sunflower, mung bean). 

The laboratory standard procedure, based on OECD Guideline 208, was conducted in an artificial 

soil consisting of potting compost and sand for up to 21 days. Growth (shoot fresh weight) was the 
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most sensitive endpoint and resulted in NOEC value of 100 mg/kg dw for all three species. The 

EC50 values were 167, 289 and 316 mg/kg dw for the sorghum, sunflower and mung bean, 

respectively. Figge and Schoberl (1989) tested the effects of a defined mixture of LAS 

(composition not reported) to several crop species. Studies were conducted in a “plant metabolism 

box” consisting of natural soil cores taken from two different ecosystems. Radiolabeled LAS 

absorbed to digested sludge was incorporated into the soils, which were then planted with either 

grass, bush beans, radishes, or potatoes and maintained for either 76 or 106 days. The resulting 

NOEC values were 27.2 mg/kg dw for grass, beans and radishes, and 16.2 mg/kg dw for potatoes. 

Table 17. Results of LAS Exposure on Terrestrial Plants (in mg/kg dry weight)1

Species Endpoint EC10 EC50 NOEC Reference 

Grass, Beans, Radishes Biomass 27.2* Figge and Schoberl 1989, 

dossier 4.6.2b 

Potatoes Biomass 16.2* Figge and Schoberl 1989, 

dossier 4.6.2b 

Sorghum bicolour (crop 

sorghum) Growth 167 100 Windeat 1987 

Helianthus annuus 

(sunflower) Growth 289 100 Windeat 1987 

Phaseolus aureus (mung 

bean) Growth 316 100 Windeat 1987 

1

Reliability of Studies = (2) 

* Highest concentration tested.

Additional terrestrial plant studies are included in the LAS dossier. The reliability of the NOEC 

and EC10 values for these additional studies could not be adequately assessed because the original 

studies were not available for review. Therefore, they are not included in Table 17. 

The potential for LAS and other surfactants to influence defoliation in coastal trees was reviewed in a 

literature review (Hamwijk 2002). In laboratory studies in which young trees are exposed to artificial 

sea spray, it has been demonstrated that the presence of surfactants at a concentration that causes a 

dynamic surface tension < 30 mN/m lead to an increased foliar penetration of NaCl via the stomata. 

For example, Grieve and Pitman (1978) examined the influence of surfactants on foliar NaCl uptake 

in Norfolk Island Pines (Araucaria heterophylla). Plants were exposed to seawater with different 

concentrations of LAS. At 10 mg/L of LAS, which corresponds with a reduced surface tension of 32 

mN/m, the Na+

 content in the foliage increased almost tenfold to a level of approximately 500 μmol/g 

dw and damage symptoms were recorded. It was found that a low surface tension increases the 

contact angle with the leave and makes it possible for an aqueous solution to enter the stomata. 

Richard et al. (1996) reported the results of a 2-minute exposure of pine trees (Pinus halepensis) to 

14C-LAS (58 mg/L). LAS was primarily absorbed in the epicuticular waxes of the pine needles with 

very little in other plant material. The amount of absorption, and changes in wax fine structure 

(SEM), was much greater for LAS in seawater (where surface tension = 29 mN/m) than in distilled 

water (surface tension = 45 mN/m). However, the concentrations of LAS in seawater (section 2.2.8) 

are much lower than those required to increase foliar penetration in these studies, suggesting that this 

mechanism may not be relevant to coastal tree defoliation. 
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Terrestrial Toxicity – Avian 

One non-guideline study is available in which the effects of commercial LAS (not specified) on 

Leghorn chicken hens is evaluated (Lopez-Zavalla et al. 1975). Ten month old hens were given a 

200 ppm dose in drinking water for 45 days, during which mortality and egg quality were measured. 

No effects were observed and, while non-traditional, the study does indicate that up to 200 mg/kg in 

the drinking water does not adversely affect hen survival or egg-laying. See Dossier section 4.6.3 

for more information. 

Terrestrial Toxicity – Field Studies 

Jensen and Krogh (1999; dossier section 4.7d) did not observe any short-term or long-term (4 years) 

adverse effects on 9 different microbial functions/processes or the abundance or diversity of 

microanthropods and earthworms after sludge application resulting in LAS soil concentrations of 15 

mg/kg dry weight. Brandt et al. (2003; dossier section 4.7c) found that C11.6 LAS spiked into sludge 

at levels of 7.1 or 31.3 g/kg dry matter did not adversely effect the function of the microbial 

community in sludge-amended, well-drained (and thus primarily aerobic) agricultural soils. The 

study should be considered a worst-case due to the application of high LAS concentrations only 

occasionally encountered in sewage sludge (Cavalli and Valtorta 1999, Waters et al. 1989; dossier 

section 3.2p,o), the use of LAS-spiked sludge possible overestimating the actual bioavailability 

relative to aged surfactants in natural sludge, the application of relatively large (4 x 4 cm) two 

dimensional sludge bands possible retarding oxygen intrusion and consequently LAS degradation in 

the sludge relative to smaller spherical sludge clumps present under more realistic field conditions, 

and the use of a coarse, sandy soil with relatively low organic matter content. 

4.3 Other Environmental Effects 

Evaluation of Estrogenic Effects

LAS has been evaluated to determine whether it could be an endocrine disrupter using a 

recombinant yeast screen (Routledge and Sumpter 1996: Navas et al. 1999) and a vitellogenin assay 

using cultured trout hepatocytes (Navas et al. 1999). No signs of estrogenic effects were observed 

for LAS or its sulfophenyl carboxylate (SPC) biodegradation intermediates, as expected from the 

absence of any structural alert. 

4.4 Initial Assessment for the Environment 

Pure LAS is a solid at ambient temperatures with a melting point of 198.5°C. The boiling point for 

LAS could not be determined experimentally due to decomposition beginning at 444°C. LAS has a 

low vapor pressure (calculated as 3-5 x 10-13 Pa). LAS is water soluble, with a critical micelle 

concentration (CMC) value of 0.1 g/L and forms a clear solution in water at concentrations up to 

250 g/L. Although it is impossible to accurately measure an octanol-water partition coefficient for 

surface-active agents like LAS, an octanol-water partition coefficient of log 3.32 has been 

calculated for C11.6 LAS. Kd values for LAS in activated sludge and sediment increased with 

increasing alkyl chain length of LAS homologues with Kd values for C12 LAS of 3210 L/kg in 

activated sludge and 330 L/kg in river sediment. In activated sludge, sorption and desorption 

equilibria for LAS were achieved very rapidly, and comparison of the extent of sorption and 

biodegradation shows that the absorbed fraction as well as the soluble fraction of LAS is available 

for biodegradation. Based on Fugacity III modeling results using the most relevant input 

parameters, more than 99 percent of the residual (non-biodegraded) fraction of LAS distributes to 

the soil. LAS does not undergo significant degradation by abiotic mechanisms under 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 49

environmentally relevant conditions as photolyzable and hydrolyzable groups are absent from the 

chemical structure. 

An extensive database of studies demonstrates rapid and complete (ultimate) biodegradation of LAS 

in many of the available aerobic biodegradation tests, including soil and the aqueous environment. 

In several tests, LAS has been shown to be readily biodegradable, and has passed the 10-day 

biodegradation window in mineralization tests for most ready tests. LAS is removed in biological 

wastewater treatment at percentages ranging from 77-82% for trickling filters up to 99%+ for 

activated sludge. The biodegradation kinetics of the longer alkyl chain lengths are generally faster, 

and their sorption coefficients larger. The primary degradation intermediates are sulfophenyl 

carboxylates (SPCs), which further degrade to CO2, SO4

2-, and water. LAS does not generally 

degrade under anaerobic conditions. The measured bioconcentration factors of pure homologues 

and isomers decrease with decreasing average alkyl chain lengths (from almost 1000 for 2-phenylC13 LAS to 2 for 6-phenyl-C10 LAS), all with rapid clearance. The calculated BCF for currently 

produced C11.6 LAS is 87 and was 22 for filtered Mississippi River water (average alkyl chain 

length of surface water fingerprint = C10.8). 

Ecotoxicity data are extensively available for LAS, with several comprehensive reviews having 

been completed. The lowest reliable acute LC50/EC50/ErC50 values based on a review of the aquatic 

toxicity data on commercially representative LAS (C11.6-C11.8) were 1.67, 1.62 and 29.0 mg/L for 

fish, Daphnia magna, and algae, respectively. Acute toxicity is greater for individual LAS 

homologues with longer alkyl chain lengths. LAS biodegradation intermediates are significantly 

less toxic than the parent LAS with L/EC50 values >1000 mg/L for fish and D. magna. Chronic 

freshwater toxicity studies following guideline exposures (28-30 days for fish, 21 days for 

invertebrates and 3-4 days for algae provided the following NOEC values: fish NOEC = 1 mg/L 

(two studies, two species); Daphnia, NOEC = 1.18-3.25 mg/L (six values, two studies, one with 5 

diets); algae, NOEC = 0.4-18 mg/L (four studies, two species). In addition all of the available, 

reliable chronic single species aquatic toxicity data on LAS have been evaluated, including three 

freshwater species in which multiple studies were reported and nine freshwater species for which 

single studies were reported. Single NOEC values and geometric mean NOEC values (calculated 

for species with multiple species) were normalized to C11.6 LAS. These NOEC values range from 

0.25 to 6.1 mg/L for freshwater species, including fish, invertebrates, algae and higher plants. 

Geometric mean NOEC values for marine species ranged from 0.025 to 5.0 mg/L. Based on the 

model ecosystem studies, a NOEC of 0.27 mg/L (0.37 if normalized to C11.6 LAS) was determined 

for the freshwater ecosystem. This value is based on model stream ecosystem studies of over 250 

species, and is consistent with the single species chronic freshwater data. 

NOEC values for sediment exposures were greater than or equal to 81 mg/kg dry matter based on 

studies in four species, including GLP studies in L. variegates (survival, reproduction and growth 

over 28 days) and C. elegans (egg production, 3 days). Field studies indicate no adverse effects of 

LAS in sludge-amended soil from LAS levels of 15 mg/kg dry matter in the soil (9 microbial 

functions/processes and abundance/diversity of microarthropods and earthworms, short-term and 4 

years) or 31,300 mg/kg dry matter in sludge (function of microbial community, short-term and 1 

year). 

In laboratory studies in which young trees are exposed to artificial sea spray, LAS concentrations of 

10 mg/L lead to increased foliar penetration of NaCl, a hypothesized mechanism of defoliation. 

A health and environmental risk assessment is available (heraproject.com); the risk assessment has 

not been reviewed by the U.S. Environmental Protection Agency. 

Results of extensive environmental monitoring evaluations in the United States indicate that 

measured surface water concentrations were generally below 50 μg/L for river water samples 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 50

collected under low dilution (worst case) conditions below treatment plant mixing zones. Values in 

the 2800 km reach of the Mississippi River from Minneapolis to New Orleans range from nondetect (<0.1 μg/L) to 28 μg/L (362 samples). LAS river water concentrations similar to those in the 

US were observed in monitoring studies conducted in Europe and Japan. 

Measured LAS concentrations in river sediments were generally less than 1-2 mg/kg dry weight. 

Mississippi River sediments were <1 mg/kg dry matter with one exception. LAS levels in 

sediments of the receiving waters of the Tiber River (Italy) were 1.8 mg/kg dry matter. Higher LAS 

concentrations have been observed near untreated or poorly treated wastewater discharges, e.g. 

LAS in sediments of a small river (Rapid Creek, USA) below a trickling filter treatment plant 

averaged 190 mg/kg just below the outfall, 11.2 mg/kg less than 5 miles downstream and 5.3 mg/kg 

greater than 5 miles downstream. 

5 RECOMMENDATIONS 

Human Health: The chemicals in the LAS category are currently of low priority for further work 

because of their low hazard potential except for skin and eye irritation and acute inhalation. Based 

on data presented by the Sponsor Country, exposure to respirable particles is anticipated to be low. 

Other countries may desire to investigate any exposure scenarios that were not presented by the 

Sponsor Country. 

Environment: The chemicals in the LAS category possess properties indicating a hazard for the 

environment (fish, invertebrates and algae). However, they are of low priority for further work due 

to ready and/or rapid biodegradation and limited potential for bioaccumulation. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 51

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Annex 1 – Use and Exposure Information 

Linear Alkylbenzene Sulfonate (LAS) 

Member countries did not evaluate the exposure annex 

and therefore, can make no conclusions regarding these 

values. 
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Annex 1 – Use and Exposure Information 

Linear Alkylbenzene Sulfonate (LAS) 

Industry Coalition for the SIDS Assessment of LAS 

August 11, 2003 

Purpose 

To provide high end to bounding estimates of the potential environmental and human exposure to 

LAS from its manufacture and its use in consumer, commercial and industrial products in the 

United States to complement an OECD SIDS Programme review of this category. 

Coverage 

The report covers exposure from manufacturing and consumer/commercial/industrial use for all 

LAS volumes produced and used in the United States. 

Synthesis of Key Assessment Results 

Background: LAS is a mixture of closely related isomers and homologues covering several CAS 

numbers, each containing an aromatic ring sulfonated at the para position and attached to a mostly 

linear (87-98%) alkyl chain. It is an anionic surfactant that has been widely used since its 1964 

introduction as the primary cleaning agent in consumer/commercial/industrial laundry detergents 

and cleaning products. This chemistry replaced branched alkylbenzene sulfonate (BABS), 

eliminating excessive foaming of sewage treatment plants and receiving waters caused by the poor 

biodegradability of BABS. 

Results Summary: Approximately 390,000 metric tons of LAS are consumed annually in North 

America (United States and Canada combined). Production in Europe is approximately 400,000 

metric tons. Production in Japan is approximately 85,000 metric tons. About 78-97% of the LAS 

consumption worldwide is in liquid, dry and tablet forms of laundry and fine fabric detergents. 

Another 2-10% is used in dishwashing liquids, with the remainder used in other cleaners. The 

predominant disposal route for these products is via wastewater. LAS is water soluble (250 g/L) and 

has low vapor pressure (3E-13 Pa). The low volatility and production of LAS in tablet, 

powder/granular and liquid forms minimize the potential for inhalation. It is effectively removed in 

biological wastewater treatment (up to 99+%) and is rapidly and completely biodegraded (70-

90+% in ≤28 days). It has low potential for bioaccumulation (BCF - 87 L/kg), with rapid clearance. 

These characteristics help to minimize the potential for human and environmental exposure. 

Engineering controls (e.g., exhaust ventilation, dust collection) and personal protective equipment 

(e.g., protective clothing, eyewear, and gloves) in place at facilities that manufacture liquid and dry 

materials sufficiently mitigate worker exposure to LAS. The aquatic NOEC is 270 μg/L based on 

the Belanger et al. (2002) review of mesocosm studies, which concluded that a NOEC of 0.27 mg/L 

(0.37 mg/L if normalized to C11.6 LAS) was the most reliable, defensible and robust value for LAS 

in the aquatic ecosystem. Results of extensive environmental monitoring evaluations in the United 

States indicate that measured surface water concentrations were generally below 50 μg/L for river 

water samples collected under low dilution (worst case) conditions below treatment plant mixing 

zones and range from non-detect (< 0.1 μg/L) to 28 μg/L in the 2800 km reach of the Mississippi 

River. An appropriate NOAEL from animal studies for use as a comparison is 85 mg/kg (see 

reasons stated in the main text of the SIAR). Modeled estimates of environmental exposure leading 

to indirect human exposure from drinking water and fish consumption range from 3.5 x 10-5 to 9.3 x 

10-7 mg/kg/day. Similarly, the results of the dermal exposure modeling for various activities range 

from 5.6 x 10-2 to 4.7 x 10-5 mg/kg/day. These human exposure evaluations include conservative 
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UNEP PUBLICATIONS 65

(protective) input assumptions (e.g. all modeled exposures are conservative by a factor of at least 

100 due to use of a default assumption of 100% absorption vs. a measured value of 1%). 
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Format A: General Information

I. Identification Information

(1) Date of Submission 2003-11-06 

(2) Identity of Organization 

Industry Coalition for the SIDS Assessment of LAS 

John E. Heinze, Ph.D., Manager 

529 14th Street, NW, Suite 807 

Washington, DC 20045, USA 

202-737-0171 (tel) 

202-737-8406 (fax) 

jheinze@johnadams.com

(3) Table of Contents 

Format A: General Information 

Substance Information 

Purpose and Coverage of this Report 

Summary 

Production, Import and Use 

Activities, Releases and Exposures, and Factors that Mitigate or Exacerbate Exposures 

Format B: Monitoring Evaluations

Evaluation #1: Surface waters and sediments in the Mississippi River 

Evaluation #2: Wastewater treatment plant influents, effluents and surface water 

Format C: Modeling Evaluations 

Evaluation #1: Environmental Exposure from Manufacturing Facility Effluent Discharge 

Aquatic exposure 

Drinking water exposure 

Fish consumption exposure 

Evaluation #2: Environmental Exposures from Consumer Use 

Aquatic exposure 

Drinking water exposure 

Fish consumption exposure 

Evaluation #3: Dermal Exposures from Consumer Use of Products 

Use of diluted and undiluted laundry and dishwashing products 

Use of diluted and undiluted cleaning products 

Laundry product residual on clothing 

Face and Hand soap residual 
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CH3(CH2)

5CH(CH2)4CH3

S03

 - Na+

II. Substance information 

(1) Category name 

Linear Alkylbenzene Sulfonate (LAS) 

(2) Substance Name(s) and CAS RN 

1322-98-1 Decylbenzene sulfonic acid, sodium salt 

25155-30-0 Dodecylbenzene sulfonic acid, sodium salt 

26248-24-8 Tridecylbenzene sulfonic acid, sodium salt 

27636-75-5 Tridecylbenzene sulfonic acid, sodium salt 

68081-81-2 C10-16 Monoalkylbenzene sulfonic acid, sodium salt 

68411-30-3 C10-13 Alkylbenzene sulfonic acid, sodium salt 

69669-44-9 C10-14 Alkylbenzene sulfonic acid, sodium salt 

85117-50-6 C10-14 Monoalkylbenzene sulfonic acid, sodium salt 

90194-45-9 C10-13 Alkyl derivatives benzene sulfonic acid, sodium salt 

127184-52-5 4-C10-13-sec Alkyl derivatives benzene sulfonic acid, sodium salt 

(3) Substance Formula and Structure 

The LAS molecule contains an aromatic ring sulfonated at the para position and attached to a linear alkyl 

chain at any position except the terminal carbons (Valtorta et al., 2000). The alkyl carbon chain typically has 

10 to 14 carbon atoms. The linearity of the alkyl chains ranges from 87-98%. While commercial LAS 

consists of more than 20 individual components, the ratio of the various homologues and isomers, 

representing different alkyl chain lengths and aromatic ring positions along the linear alkyl chain, is relatively 

constant across the various detergent and cleaning applications, with the average carbon number of the alkyl 

chain varying between 11.7-11.8. Because of the close consistency of the mixtures, their commercial uses, 

fate and effects, LAS is discussed as a category rather than as individual CAS numbers in this assessment. 

The structure of a C12-LAS, representative of the category, is shown in the figure. 

(4) Physical Form 

All members of the category are solid at room temperature; melting point >198.5°C. 

(5) Other Constituents 

Some methyl-substituted (i.e., iso-branched) LAS may be present in the mixtures (Nielsen et al. 1997). The 

amount of the iso-LAS component is small (1-6%) and was shown not to limit biodegradation relative to pure 

linear component (Nielsen et al. 1997; Cavalli et al. 1999). Non-linear components such as dialkyltetralin 

sulfonates (DATS) can be present at levels of less than 1 to 8% depending on the manufacturing process 

(Nielsen et al 1997). The presence of these amounts of DATS does not significantly affect the biodegradation 

of LAS (Nielsen et al 1997). Improvements in processing techniques in the US, Europe and Japan incorporated 

to increase LAS yields also reduce the amount of DATS present in LAS.
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III. Purpose and Coverage of this Report 

(1) Purpose 

To provide high end to bounding estimates of the potential environmental and human exposure to LAS 

from its manufacture and its use in consumer, commercial and industrial products in the United States to 

complement an OECD SIDS Programme review of this category. 

(2) Coverage 

The report covers exposure from manufacturing and consumer/commercial/industrial use for all LAS 

volumes produced and used in the United States. 

IV. Summary 

(1) Synthesis of Key Assessment Results 

BACKGROUND: LAS is a mixture of closely related isomers and homologues covering several CAS 

numbers, each containing an aromatic ring sulfonated at the para position and attached to a mostly linear 

(87-98%) alkyl chain. It is an anionic surfactant that has been widely used since its 1964 introduction as 

the primary cleaning agent in consumer/commercial/industrial laundry detergents and cleaning products. 

This chemistry replaced branched alkylbenzene sulfonate (BABS), eliminating excessive foaming of 

sewage treatment plants and receiving waters caused by the poor biodegradability of BABS. 

RESULTS SUMMARY: Approximately 390,000 metric tons of LAS are consumed annually in North 

America (United States and Canada combined). Production in Europe is approximately 400,000 metric 

tons. Production in Japan is approximately 85,000 metric tons. About 78-97% of the LAS consumption 

worldwide is in liquid, dry and tablet forms of laundry and fine fabric detergents. Another 2-10% is used 

in dishwashing liquids, with the remainder used in other cleaners. The predominant disposal route for 

these products is via wastewater. LAS is water soluble (250 g/L) and has low vapor pressure (3E-13 Pa). 

The agglomeration process for production of modern powder/granular detergent formulations minimizes 

the potential for inhalation of LAS from dust. LAS is effectively removed in biological wastewater 

treatment (up to 99+%) and is rapidly and completely biodegraded (70-90+% in ≤28 days). It has low 

potential for bioaccumulation (BCF - 87 L/kg), with rapid clearance. These characteristics help to 

minimize the potential for human and environmental exposure. Engineering controls (e.g., exhaust 

ventilation, dust collection) and personal protective equipment (e.g., protective clothing, eyewear, and 

gloves) in place at facilities that manufacture liquid and dry materials sufficiently mitigate worker 

exposure to LAS. The aquatic NOEC is 270 μg/L. Results of extensive environmental monitoring 

evaluations in the United States indicate that measured surface water concentrations were generally below 

50 μg/L for river water samples collected under low dilution (worst case) conditions below treatment plant 

mixing zones and range from non-detect (<0.1 μg/L) to 28 μg/L in the 2800 km reach of the Mississippi 

River. An appropriate NOAEL from animal studies for use as a comparison is 85 mg/kg (see 

reasons stated in the SIAR). Modeled estimates of environmental exposure leading to indirect human 

exposure from drinking water and fish consumption range from 3.5E-5 to 9.3E-7 mg/kg/day. Similarly, 

the results of the dermal exposure modeling for various activities range from 5.6E-2 to 4.7E-5 mg/kg/day. 

These human exposure evaluations include conservative (protective) input assumptions (e.g. all modeled 

dermal exposures are conservative by a factor of at least 100 due to use of a default assumption of 100% 

absorption vs. a measured value of 1%). 

(2) Summary of Data Collection Efforts 

Information in this assessment was assembled from a number of sources: 

1) Surveys of member companies of the Industry Coalition for the SIDS Assessment of LAS, representing 

about 75% of LAS producers and users, collected data on LAS production volumes, uses, releases, and 

potential exposures. To protect proprietary information, independent counsel compiled the resulting data. 

Two recent economic reviews, published by Colin A Houston and SRI international, were used to confirm 

the compiled results for the U.S. Additional information was also derived from a report prepared by the 

“Human and Environmental Risk Assessment on ingredients of European household cleaning products” 

(HERA 2004). 

 
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2) Environmental monitoring data were collected via two comprehensive US studies. The first determined 

LAS surface water and sediment concentrations over 3 separate research vessel cruises on the 2800 

kilometer reach of the Mississippi River between Minneapolis and New Orleans in three seasons of 1991-

92. The second determined concentrations of LAS in wastewater plants and surface waters, at 50 locations 

in 11 states. These data are summarized in Format B attachments. 

3) Potential LAS exposures estimated via modeling are summarized in Format C attachments. Potential 

exposures resulting from manufacturing facility effluent discharges are modeled using US EPA’s E-FAST 

model. This modeling includes estimates of aquatic exposure based on modeled surface water 

concentrations. Potential human exposure is estimated based on modeled drinking water concentrations 

and fish consumption from sources downstream from effluent discharges. Similarly, potential aquatic 

exposures and human exposures from drinking water and fish consumption are modeled using E-FAST 

following consumer use of products containing LAS (i.e., down-the-drain releases). Finally, dermal 

exposures from consumer uses of products are examined using general exposure models for three exposure 

scenarios: 1) use of diluted and undiluted laundry and cleaning products (laundry pre-treatment, handwash of laundry, hand-wash of dishes, washing of hands with dishwashing liquid) and diluted and 

undiluted hard surface cleaning products; 2) exposure to laundry and fabric conditioning product residual 

on clothing (liquid, dry and tablet laundry detergents, dryer sheet fabric conditioner); and 3) exposure to 

face and hand soap residual after use. 

(3) Discussion of Key Uncertainties, Limitations, Data Gaps 

a) Manufacturers representing about 75% of the US volume were involved in the industry survey. Thus, it 

is possible that there may be minor uses and potential consumer exposures beyond those estimated here. 

However two recently published economic reviews and a published European assessment support the uses 

presented. In the assessment, the estimated volume encompassing all US producers was used and 

exposure estimates are presented for all known uses. 

b) This exposure assessment takes a conservative (protective) approach to modeling, selecting inputs 

based on conservative values for each parameter; thus modeled estimates are likely to significantly exceed 

actual exposures. For predicted environmental exposures, this is supported by a comparison of monitoring 

results to modeling estimates. For consumer exposure, actual dermal absorption is less than 1% of product 

(Schaefer and Redelmeier 1996), whereas all modeled exposures include a default assumption of 100% 

absorption. Therefore, the modeled exposure is conservative by a factor of at least 100. 

c) Several scenarios are not modeled—direct and indirect oral, inhalation, and sediment—but information 

is presented to establish that exposure from these scenarios are not significant compared to the scenarios 

that are discussed in detail. 
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(4) Exposure Results 

The following table shows the estimated exposure for the scenarios assessed, and the NOEC or NOAEL 

values.

Exposure Scenario Estimated Exposure 

(μg/L) or (mg/kg/day) 

NOEC (μg/L)* or 

NOAEL 

(mg/kg/day)** 

Surface Water Monitoring 

Mississippi River 2.21 270* 

50 U.S. Rivers 43 to 46 270* 

Manufacturing Effluent Modeling 

Aquatic 

Mean stream conc. 

7Q10 Stream conc. 

50th percentile facility 

4.8 

13 

270* 

270* 

Drinking Water Consumption 

50th percentile facility 9.3E-7 85**

Fish Consumption 

50th percentile facility 3.5E-5 85**

Consumer Use Modeling 

Aquatic 

 Median flow 

7Q10 flow 

9.9E-2 

1.3 

270* 

270* 

Drinking Water Consumption 

7Q10 flow 1.9E-6 85**

Fish Consumption 

7Q10 flow 7.2E-7 85**

Consumer Use – Dermal Modeling 

Diluted and undiluted laundry and dishwashing products and hard surface cleaning products 

Laundry pre-treatment (diluted) 3.0E-3 to 6.0E-3 85**

Neat Laundry pre-treatment (undiluted) 5.0E-3 to 1.0E-2 85**

Hand-wash of laundry (diluted) 4.7E-5 to 1.2E-3 85**

Hand-wash of dishes (diluted) 5.0E-4 to 2.3E-3 85**

Hand-wash (dishwashing liquids) of 

hands (diluted) 1.0E-4 to 7.4E-4 85**

Hard surface cleaners (diluted) 1.0E-3 to 5.0E-4 85** 

Hard surface cleaners (undiluted) 5.0E-3 to 1.0E-3 85**

Laundry product residual on clothing 

Liquid detergents 2.0E-3 to 5.0E-2 85**

Dry detergents 1.0E-2 to 5.0E-2 85**

Tablet laundry detergent 1.1E-2 to 5.6E-2 85** 

Fabric conditioning (dryer sheets) 5.0E-5 to 3.0E-4 85** 

Face and Hand Soap product residual after washing 

Bar soap - hand 3.6E-3 to 1.8E-2 85**

Bar soap - face 5.0E-4 to 2.3E-3 85**
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The dermal exposures are also summarized below aggregated by product category use. The aggregation was 

accomplished by adding the modeled exposures within a product category, e.g., three scenarios for liquid 

detergent exposures were modeled – hand-washing, neat pre-treatment, and residual on clothing. These 

human exposure evaluations include conservative (protective) input assumptions (e.g. all modeled exposures 

are conservative by a factor of at least 100 due to use of a default assumption of 100% absorption vs. a 

measured value of 1%). 

Product Type Estimated Exposure 

(mg/kg/day) NOAEL (mg/kg/day) 

Laundry Detergent – Liquid 7.0E-3 to 6.1E-2 85 

Laundry Detergent – Dry 1.4E-2 to 6.3E-2 85 

Dish Detergent 6.0E-4 to 3.0E-3 85 

Hard Surface Cleaners 1.0E-3 to 5.0E-4 85 

Fabric Conditioning (dryer sheet) 5.0E-5 to 3.0E-4 85 

Bar Soap 4.1E-3 to 2.0E-2 85 

V. Production, Import and Use 

(1) Estimated Volume (tonnes/year) 

US/Canada – 390,000 tonnes/yr (2000 data, Colin A. Houston 2002) 

Europe – 400,000 tonnes/yr (2001 data, HERA 2004) 

Japan – 85,000 tonnes/yr (2000 data, LAS SIDS Coalition Survey 2002) 

(2) Function/ Product Use Categories and Percent Volume to Each 

LAS is a surfactant, used as the primary cleaning agent in a variety of consumer/commercial/industrial 

laundry and cleaning products. About 78-97% of LAS consumption worldwide is in liquid, dry and tablet 

laundry and fine fabric detergents. Another 2-10% is used in dishwashing liquids, with the remainder used in 

other cleaners. 
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VI. Activities, Releases and Exposures, and Factors that Mitigate or Exacerbate Exposures by Activity 

Manufacture 

(1) Process Description 

LAS is produced from the sulfonation of linear alkylbenzene (LAB) to make an intermediate, LAB sulfonic 

acid. The acid is produced primarily by oleum or air/SO3 sulfonation, in batch or continuous processing 

equipment in enclosed sulfonation facilities. The entire production of LAB sulfonic acid is used in the 

production of LAS. LAS is formed when the LAB sulfonic acid is neutralized to the sodium salt with sodium 

hydroxide or other base. LAS is produced in a closed system process as both dry product and as an aqueous 

solution. There are 22 LAS manufacturing facilities in the US. (Colin Houston, 2000). The following 

manufacturing and mitigation measures apply to all of the manufacturing facilities operated by members of 

the Coalition in Canada, Europe, Japan and the United States (LAS SIDS Coalition Survey, 2002). 

(2) General Description of Potential Releases and Exposures 

Potential releases to the environment are minimal due to manufacturing processes that have been designed to 

maximize production yield and minimize potential releases. Extensive engineering controls are in place to 

minimize releases to the environment. These controls include SO2/SO3 monitoring devices, spill containment 

dikes for rail unloading, leak inspections, high level tank alarms, and auto shut off valves. Emissions controls 

include line cyclones, electrostatic precipitation and passing through caustic scrubbers and scrubbing 

demisters. Any LAS that is not incorporated into a product is captured by dust-handling equipment for 

recycling back into the production process. A limited amount of LAS in aqueous solution may be released as 

a dilute solution from washing and rinsing operations in the manufacturing process. Any minimal LAS 

released from manufacturing plants that produce or formulate LAS is discharged to wastewater treatment. 

Incidental quantities of the dry product (e.g., from floor sweepings) may be disposed in landfills. 

Potential workplace exposures include inhalation of dust, dermal contact with powders, granules and liquids; 

there is the potential for incidental or accidental ingestion, and/or eye contact with the product during 

handling in the manufacturing process. 

(3) Discussion of Factors that Mitigate or Exacerbate Releases and Exposures 

LAS is water soluble (250 g/L) and has low vapor pressure (3E-13 Pa). The low volatility and production of 

LAS in tablet, powder/granular (e.g., use of Good Manufacturing Practices, personal protective equipment) 

and liquid (e.g., droplet size controls) forms minimize the potential for inhalation. It is effectively removed 

in biological wastewater treatment (up to 99+%) and is rapidly and completely biodegraded (70-90+% in 

≤28 days). It has low potential for bioaccumulation (BCF - 87 L/kg), with rapid clearance. These 

characteristics help to minimize the potential for human and environmental exposure. 

LAS environmental releases are not regulated independently, but as part of overall facility emissions. 

Mitigation includes use of good manufacturing practices, best available technology and engineering controls. 

Engineering controls (e.g., exhaust ventilation, dust collection) and personal protective equipment (e.g., 

protective clothing, eyewear, and gloves) in place at facilities that manufacture liquid and dry materials 

sufficiently mitigate worker exposure to LAS. All processing of LAB, LAB sulfonic acids and LAS takes 

place in closed systems that significantly minimize worker exposure. Workers also wear standard personal 

protective equipment including safety goggles, face shields, safety shoes, impervious nitrile gloves, long 

sleeved clothing, and rubber boots. Workers may also employ cartridge-type respirators equipped with 

organic vapor cartridges and acid-resistant suits, for example, during steaming and washing. The closed 

production process and use of personal protective equipment effectively eliminates exposure to production 

workers. No special engineering controls and no additional personal protective equipment are uniquely 

specified for LAS. 

(4) Remarks 

Product formulation, the blending of LAS with other ingredients, is not expected to result in workplace 

exposures that exceed those for LAS manufacturing facilities. In some cases, LAS is blended into finished 

products in the same facilities where it is produced, in other cases the facilities are separate. In all cases, 

engineering controls and personal protective equipment are similar. 
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Industrial Use 

(5) Function/Product Use Description 

A minor amount of LAS production (0.003%) has industrial uses. The vast majority of the production used 

for industrial purposes are as plasticizers in masonry admixtures (~60%) and air entraining agents in concrete 

admixtures (~40%). Polymer stabilizers in food packing films and dispersing agents in sealant materials for 

can ends, pail lids, and drums make up no more than about 3% of total Industrial uses. 

(6) General description of Potential Releases and Exposures 

There is a low potential for incidental dermal, ingestion, inhalation or eye contact with the product during 

handling and use. There is also a low potential for environmental release from industrial uses of LAS. 

(7) Discussion of Factors that Mitigate or Exacerbate Releases and Exposures 

Exposure to LAS in industrial products is mitigated by following use and precaution instructions on product 

labels. 

(8) Remarks 

Industrial uses make up an insignificant portion of the total LAS production. LAS is manufactured for use in 

consumer and commercial/institutional laundry and cleaning product formulations and is not used as an 

intermediate/derivative for further chemical manufacturing processes. 

Commercial Use 

(9) Function/Product Use Description 

LAS is a surfactant used in commercial laundry and cleaning products that are either used as supplied or 

diluted prior to use. Uses include institutional and industrial products; for example: 

Product Type Concentration in Products in US/Canada

 (range)

Laundry detergents (dry) 5-25 % 

Dishwashing detergents (liquids) 5-10 % 

General cleaners 1-5 % 

Disinfectant cleaners (liquids) 5-10 % 

Product Type Concentration in Products in Europe

 (range)

Laundry detergents (dry) 5-10 % 

Laundry detergents (liquids) 10-25 % 

Pre-washes 10-25 % 

Dishwashing detergents (liquids) 25-50 % 

Product Type Concentration in Products in Japan

 (range)

Laundry detergents (dry) 5-10 % 

Dishwashing detergents (liquids) 5-50 % 

Hard surface cleaners 1-10% 
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(10) General description of Potential Releases and Exposures 

Laundry and cleaning products may be used as is, or diluted prior to or during use. 

Dermal contact may occur with commercial products. There is a low potential for incidental or accidental 

ingestion of, inhalation of, and/or eye contact with the product during handling and use. 

Environmental releases from down-the-drain discharges following product use could lead to potential 

ecological exposures in surface waters and indirect human exposures via drinking water and fish 

consumption. These potential exposures are quantified in the following pages based on monitoring data 

(Format B) and modeling data (Format C). 

(11) Discussion of Factors that Mitigate or Exacerbate Releases and Exposures 

Exposure to LAS in formulated commercial laundry or cleaning products is mitigated by following use and 

precaution instructions on product labels. Product labels reflect the hazard potential of the chemical 

ingredients in the product. These product labels also include first aid instructions to accompany each hazard 

warning. For example, commercial products may include eye and skin irritancy warnings along with 

instructions to rinse thoroughly if dermal or other exposure occurs. 

LAS is water soluble (250 g/L) and has low vapor pressure (3E-13 Pa). Commercial products containing 

LAS are disposed of down-the-drain and transported to wastewater treatment plants where LAS is effectively 

removed (up to 99+%). Residual LAS entering the environment is rapidly and completely biodegraded (70-

90+% in ≤28 days in standard tests). It has a low potential for bioaccumulation (BCF – 87 L/kg) and studies 

indicate that it is rapidly metabolized and eliminated from the bodies of aquatic organisms. These 

characteristics help to minimize the potential for environmental and human exposure. 

(12) Remarks: Estimates of inhalation exposure apply to both consumer and commercial products as both 

use the same type of spray nozzles (for spray cleaners) and the same type of equipment to make 

powder/granulated products. The human experience with eye irritation covers both manufacturing and use of 

consumer and commercial products.
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Consumer Use 

(13) Function/ Product Use Description 

LAS has wide-spread and dispersive use as a surfactant in the following consumer products. 

Product Type Concentration in Products in US/Canada

 (range) 

Laundry detergents (dry) 5-25 % 

Laundry detergents (liquids) 1-25 % 

Laundry detergents (tablets) 5-25 % 

Fabric conditioners (sheets) 0.1-0.5 % 

Dishwashing detergents (liquids) 5-25 % 

General cleaners (dilutable) 1-5 % 

Hard surface cleaners 1-5 % 

Face and hand soaps (bars) 1-5 % 

 

Product Type Concentration in Products in Europe 

 (range) 

Laundry detergents (dry) 5-25 % 

Laundry detergents (liquids) 5-10 % 

Laundry detergents (tablets) 10-25 % 

Dishwashing detergents (liquids) 10-25 % 

General cleaners (dilutable) 1-5 % 

Hard surface cleaners 0.1-0.5 % 

Product Type Concentration in Products in Japan 

 (range) 

Laundry detergents (dry) 5-25 % 

Laundry detergents (liquids) 5-25 % 

Laundry detergents (tablets) 5-25 % 

Fine fabric detergents (liquid) 1-5 % 

Bleaches 0.1-0.5 % 

Pre-washes 5-10 % 

Dishwashing detergents (liquids) 1-5 % 

Hard surface cleaners 0.5-10 % 

Other cleaners 0.1-0.5 % 

The level (%) in products shown above is in the formulated product and does not take into account any 

dilution prior to or during use. 

(14) General Description of Direct Exposures to Consumer Products and of Potential Releases to the 

Environment Leading to Environmental Exposures and Indirect Human Exposures 

Laundry and cleaning products may be used as is, or diluted prior to or during use. 

Dermal contact may occur with laundry and/or cleaning products. There is some potential for incidental or 

accidental ingestion of, inhalation of, and/or eye contact with products during handling and use. 

Environmental releases from down-the-drain discharges following product use may lead to potential 

environmental exposures in surface waters and indirect human exposures via drinking water and fish 

consumption. 

These potential exposures are discussed in the following pages and quantified in monitoring data (Format B) 

and modeling data (Format C). 
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(15) Discussion of Factors that Mitigate or Exacerbate Releases and Exposures 

Exposure to LAS in formulated consumer laundry and cleaning products is mitigated by following use and 

precaution instructions on product labels. Product labels reflect the hazard potential of the chemical 

ingredients in the product. These product labels also include first aid instructions to accompany each hazard 

warning. For example, commercial products may include eye and skin irritancy warnings along with 

instructions to rinse thoroughly if dermal or other exposure occurs. 

Human exposure will be mitigated by the fact that residues from cleaning products are usually washed or 

rinsed off. Actual dermal absorption is only about 1% of product (Schaefer and Redelmeier 1996), whereas 

all modeled exposures include a default assumption of 100% absorption. Therefore, the modeled exposure is 

conservative by a factor of at least 100. 

LAS is water soluble (250 g/L) and has low vapor pressure (3E-13 Pa). Consumer products containing LAS 

are disposed of down-the-drain and transported to wastewater treatment plants where LAS is effectively 

removed (up to 99+%). Residual LAS entering the environment is rapidly and completely biodegraded (70-

90+% in ≤28 days in standard tests). It has a low potential for bioaccumulation (BCF – 87 L/kg) and studies 

indicate that it is rapidly metabolized and eliminated from the bodies of aquatic organisms. These 

characteristics help to minimize the potential for environmental and human exposure.

(16) Remarks: 

Direct oral exposures are not modeled in this evaluation since these would only occur via accidental 

ingestion, and result in temporary, acute symptoms. None of the uses of LAS are in products intended for 

human consumption. Potential oral indirect exposure via drinking water and fish ingestion are included in 

Modeling Evaluations 1 and 2. 

Estimates of inhalation exposure apply to both consumer and commercial products as both use the same type 

of spray nozzles (for spray cleaners) and the same type of equipment to make the powder/granulated 

products. Trigger spray systems used for spray cleaners are designed to deposit the vast majority of the 

product on the surface to be cleaned and the respirable fraction of the amount sprayed is very small. A study 

conducted for the Soap and Detergent Association (Battelle 1999) measured the under 10 micron (respirable 

particle size) fraction delivered from 6 consumer product spray nozzles. The overall mean (n=30) is 0.11% 

particles under 10 microns and the standard deviation is 0.21. The very highest observation was 0.80%. This 

testing only captured the spray particles that are under 600 microns (maximum resolution of the test 

equipment), so the actual respirable particle percent of total volume sprayed is less than 0.1%. The Battelle 

(1999) study also reported that for consumer spray products in normal use conditions, the peak breathing 

zone concentration under 10 microns ranged from 0.13-0.72 mg/m3

. HERA (2004) reported an air 

concentration of 0.35 mg/m3

 in experimental measurements of aerosol particles under 6.4 microns that are 

generated upon spraying with typical surface cleaning spray products. Using this data and assuming a worst 

case scenario, HERA modeled potential consumer exposures via inhalation of aerosols from cleaning sprays, 

predicting an exposure of 4.0E-5 mg/kg/day from this pathway, which is several orders of magnitude below 

the 5.0E-3 to 1.0E-3 predicted for total dermal exposure to spray cleaners. This information, considered 

together with low volatility of LAS and infrequent use of spray products in comparison to products involving 

dermal contact, indicates that inhalation exposures do not contribute significantly to total exposure. 

Indirect oral exposure from deposition of LAS on dishes washed with products containing LAS is not 

modeled. Due to the use of dilute solutions and the rinsing of dishes following wash, any exposure from this 

source would be very low compared to the direct dermal exposures that are modeled. 

Also not modeled is sediment exposure. Monitoring of sediments in a 2800 km reach of the Mississippi river 

indicates sediment concentrations of 0.01 to 0.95 mg/kg (mean = 0.23 ± 0.19 mg/kg) while NOEC values for 

sediment exposure are ≥81 mg/kg. 
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Format B: Monitoring Evaluation #1

I. Identification Information

(1) Activity associated with Monitoring Information 

Sampling of surface waters and sediments of the Mississippi River between Minneapolis and New Orleans 

during 1991-1992. 

(2) Citation 

Tabor, C.F. and Barber, L.B., II. 1996. Fate of linear alkylbenzene sulfonate in the Mississippi River. 

Environ. Sci. Technol. 30:161-171. 

II. Monitoring Study Design

(1) Monitoring Study Objective 

Determination of the LAS concentrations in surface waters and sediments to provide data on the water 

quality of the river. 

(2) Description of Scenario Monitored 

Samples were collected on a 2800 kilometer reach of the Mississippi river between Minneapolis and New 

Orleans during three research vessel cruises conducted in the summer (June 23-August 7) and fall 

(September 24-November 13) of 1991 and the spring (March 25-May 10) of 1992. 

III. Sampling and Analytical Methods

(1) Sampling 

Surface water cross-channel composite grab samples were collected on the upstream leg of each cruise 

(beginning at New Orleans). Discharge-averaged composite water samples were collected on the 

downstream leg of each cruise (beginning at Minneapolis). Composite bottom sediment samples were 

collected in shallow areas off the main navigation channel during the downstream leg of each cruise. 

(2) Method/ Procedure 

This monitoring study included extensive sampling of surface waters and sediments for the 2800 kilometer 

length of the Mississippi River. Dissolved LAS was isolated by passing water samples through a silica 

cartridge and eluted with acetonitrile followed by methylene chloride. LAS was extracted from sediments 

by centrifugation followed by methanol extractions. Extracts from both water and sediment were 

derivatized to form the trifluoroethyl ester of LAS. The derivatized extracts were then analyzed by 

GC/MS. Samples were collected with substantial attention to data quality and included quality control 

samples. The analytical method was chemical specific for LAS, with a detection limit of 0.1 μg/L for 

dissolved LAS. No contamination of field blanks or sample degradation during storage was observed. 

IV. Description and Results

(1) Media Sampled 

Surface water and bottom sediments 
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(2) Results 

LAS was identified in 21% of the surface water samples and 100% of the bottom sediment samples. 

Where detected, surface water concentrations ranged from 0.1 to 28.2 μg/L (mean = 2.21 ± 3.77 μg/L), 

with the highest concentrations occurring near cities such as Minneapolis and St. Louis and concentrations 

decreasing with increasing distance downstream. The average alkyl chain length for the dissolved LAS 

was C11.1 (range C10.2-12.0). 

Bottom sediment concentrations ranged from 0.01 to 0.95 mg/kg (mean = 0.23 ± 0.19 mg/kg) [one outlier 

of 20 mg/kg from an effluent transport canal was excluded], with the highest concentrations occurring 

downstream from Minneapolis, a large city located on a relatively small river. The average alkyl chain 

length of the sediment associated LAS was C11.5 (range C10.7-11.9). 

The data indicate that biodegradation and sorption are the main removal processes affecting dissolved LAS.

(3) Remarks 

The aquatic NOEC is 270 μg/L, a conservative value based on C12 LAS which is the top end of the range 

found in the environment. The mean surface water concentration measured in the Mississippi River in this 

study is 2.21 μg/L. 

NOEC values for sediment exposure are ≥81 mg/kg while sediment concentrations ranged from 0.01 to 

0.95 mg/kg (mean = 0.23 ± 0.19 mg/kg). 

V. Reliability 

 

(1) Reliability Score 2 (Reliable with restrictions) because OECD standard test methods do not exist for 

monitoring studies. However, this is a high quality study carried out with strict attention to accepted 

analytical and sample collection procedures. 
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Format B: Monitoring Evaluation #2

I. Identification Information

(1) Activity associated with Monitoring Information 

Sampling of wastewater treatment plant influents, effluents, and surface river waters from 50 locations in 

11 U.S. States. 

(2) Citation 

McAvoy, D.C., Eckhoff, W.S., and Rapaport, R.A. 1993. Fate of linear alkylbenzene sulfonate in the 

environment. Environ. Toxicol. Chem. 12:977-987. 

II. Monitoring Study Design

(1) Monitoring Study Objective 

Determination of real-world concentrations of LAS in wastewater treatment plants and surface waters. 

(2) Description of Scenario Monitored 

Samples were collected from a national distribution of drainage basins across the U.S. and from a variety of

treatment plant types. Sites were selected based on low effluent dilution and samples were collected during 

the periods of lowest flow. Influent and effluent samples were collected from each wastewater treatment 

plant. Receiving water samples were collected above and below the outfalls from each treatment plant. 

The monitoring results were also used to verify mathematical modeling predictions. 

III. Sampling and Analytical Methods

(1) Sampling 

Twenty-four hour composite samples of influent and effluent were collected from each treatment plant over 

a 3-5 day period, then further composited to represent the average concentration of LAS over the period. 

Receiving water samples were collected midchannel above the wastewater treatment plant outfalls and 

below the effluent mixing zones as a three-sample transect. 

(2) Method/ Procedure 

This monitoring study included sampling of wastewater treatment plant influents and effluents, as well as 

surface waters above and below the mixing zone in 50 river locations across the U.S. Dissolved LAS was 

isolated from solution by solid-phase separation using a SAX column and concentrations determined by 

HPLC/fluorescence analysis. The analytical method was chemical specific for LAS, with a detection limit 

of 2 μg/L for total LAS. 

IV. Description and Results

(1) Media Sampled 

Wastewater treatment influent and effluent, and river surface water samples above and below the mixing 

zone. 

(2) Results 

Average LAS influent concentrations ranged from 4.2-5.7 mg/L. Based on effluent concentrations, 

removal rates averaged 99.3% for activated sludge plants. 

LAS concentrations in samples collected under low flow conditions below the mixing zone were generally 

below 50 μg/L. The average alkyl chain length ranged from C11.8-11.9
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(3) Remarks 

The aquatic NOEC is 270 μg/L. The mean surface water concentrations measured in 50 river locations 

across the U.S. ranged from <10 to 330 μg/L with mean values of 42 to 46 μg/L. The highest 

concentration was observed in a low (less than 3-fold) dilution effluent canal below a trickling filter plant. 

All other values were <180 μg/L with more than 80% of the sites below 50 μg/L. Since several of the 

wastewater treatment plants included in this study have dilution factors less than 3, these values represent 

worst case estimates. 

Results from this study were used to validate the water-quality model PG-GRiDS under low flow 

conditions. Measured concentrations of LAS agreed well with model predictions. 

V. Reliability 

 

(1) Reliability Score 2 (Reliable with restrictions) because OECD standard test methods do not exist for 

monitoring studies. However, this is a high quality study carried out with strict attention to accepted 

analytical and sample collection procedures. 

 
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Format C: Modeling Evaluation #1 

I. Identification Information

(1) Activity associated with Modeling Information 

Manufacturing Facility Effluent Discharge - 

Environmental Exposure Including Indirect Human Exposure 

II. Modeling Objective

(1) Modeling Study Objective 

High end to bounding estimate of surface water concentration (including drinking water and fish 

consumption exposure) as a result of manufacturing facility effluent discharge. 

 

(2) Description of Modeled Scenario 

Daily release estimated from a hypothetical manufacturing facility anywhere in the US producing 20% of 

annual US volume. Accounts for wastewater treatment, in-stream dilution and bioaccumulation potential. 

Assumes 365 days of operation per year. 

III. Description of Model and Model Validation 

(1) Tool or Model 

E-FAST – Provides screening level estimates of the concentrations of chemicals released to the 

environment from industrial discharge. Designed to provide high end to bounding estimates of exposure. 

Chemical-specific and facility-specific data or defaults can be used. Modeling conducted February 2003. 

(2) Validation/ Peer Review 

Standard model (beta release) used by USEPA Office of Pollution Prevention and Toxics in screening level 

assessments 

(3) Availability and Documentation 

www.epa.gov/oppt/exposure/docs/efast.htm

IV. Inputs, Outputs, and Quality Description 

(1) Media Modeled 

Surface water, drinking water and edible fish tissue 

(2) Inputs 

Pre-treatment facility release (process loss) – 290 kg/day; estimated as follows:

 -350,000 tonnes/yr – annual production in US 

 - 958 tonnes/day– daily production assuming 365 days/yr 

 - 1.4 tonnes/day – daily process loss assuming 0.15% loss USEPA default value 

 - 0.29 tonnes/day (290 kg/day) plant release assuming hypothetical facility produces one-fifth the total 

annual production, (there are 22 production sites in the US, Colin A. Houston 2002), a 

conservative assumption is that the maximum daily process loss for a single facility is 0.29 

tonnes/day (290 kg/day) 

SIC Code is Soaps, Detergents, etc. Manufacture (2841-2844) 

Release days – 365 

Wastewater treatment removal – 99%—reasonable based on monitoring data and likelihood that microbes 

downstream of LAS production facilities will be well acclimated 

BCF – 87 L/kg—maximum value based on Tolls et al. 1997 (22-87 L/kg for C10.6-C11.6 LAS) and 

recently published mean values of 23-80 L/kg for four species for C12 LAS by Versteeg 

and Rawlings 2003. 

NOEC = 270 μg/L 

Thus, conservative estimates are used in the determination of several of the input parameters and the 
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estimation does not account for biodegradation during transport to the wastewater treatment plant (HERA 

2004). 

(3) Model Outputs 

Results following wastewater treatment; where 50th percentile represents a facility on a mid-size stream 

with average flow. 

Aquatic exposure - 

 50th percentile facility - 

 Mean stream concentration = 4.8 μg/L 

 7Q10 stream concentration = 13 μg/L 

 [7Q10 is the lowest 7-day average flow in a year that occurs on an average once every 10 years ] 

 

Drinking water exposure - 

 50th percentile facility - 

 Average Daily Dose (ADD) = 

 9.3E-07 mg/kg/day (chronic non-cancer) 

 

Fish consumption exposure – 

 50th percentile facility - 

 Average Daily Dose (ADD) = 

 3.5 E-05 mg/kg/day (chronic non-cancer) 

 

(4) Reliability Score 2 (Reliable with restrictions) The model has not been validated but is sufficiently 

conservative and accepted by authorities. Appropriate inputs have been selected reflecting best available 

information and conservative estimates where applicable. 

Modeling can be useful in first tier approach for exposure assessment. Model outputs reflect E-FAST 

model assumptions that are designed to provide high end to bounding estimates of exposure. 

(5) Remarks 

The aquatic NOEC = 270 μg/L. The estimated mean and low flow (7Q10) stream concentrations are 4.8 

μg/L and 13 μg/L, respectively, for the 50th percentile scenario. 

An appropriate NOAEL from animal studies for comparison is 85 mg/kg (see reasons stated in the 

SIAR). Estimated exposures in consumer products for the 50th percentile facility scenario are 9.3E-07 

mg/kg/day (drinking water) and 3.5E-05 mg/kg/day (fish consumption). 

Product formulation facilities are not expected to have environmental releases that exceed those for LAS 

manufacturing facilities. 
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Format C: Modeling Evaluation #2

I. Identification Information

(1) Activity associated with Modeling Information 

Consumer Use (i.e., down-the-drain release) - 

Environmental Exposure Including Indirect Human Exposure 

II. Modeling Objective

(1) Modeling Study Objective 

High end to bounding estimate of surface water concentration (including drinking water and fish 

consumption exposures) as a result of daily consumer usage of laundry and cleaning products. 

(2) Description of Modeled Scenario 

Down-the-drain release of total USA annual production volume into total volume of USA municipal 

wastewater system. Accounts for wastewater treatment and in-stream dilution. Accounts for 

bioaccumulation potential. 

III. Description of Model and Model Validation 

(1) Tool or Model 

E-FAST 

(2) Validation/ Peer Review 

Standard model (beta release) used by USEPA Office of Pollution Prevention and Toxics in screening level 

assessments 

(3) Availability and Documentation 

www.epa.gov/oppt/exposure/docs/efast.htm

IV. Inputs, Outputs, and Quality Description 

(1) Media Modeled 

Surface water, drinking water and edible fish tissue 

(2) Inputs 

Release – 350,000 tonnes (total US annual production) 

Wastewater treatment removal – 99% 

BCF estimate – 87 L/kg 

NOEC – 270 μg/L 

(3) Model Outputs 

Results following wastewater treatment; 

Aquatic exposure - 

 Mean stream flow concentration = 0.099 μg/L 

 7Q10 stream flow concentration = 1.3 μg/L 

 [7Q10 is the lowest 7-day average flow in a year that occurs on average once every 10 years ] 

 

Indirect human exposure estimates under low stream flow (7Q10) conditions are: 

Drinking water exposure - 

 Average Daily Dose (ADD) = 

 1.9E-06 mg/kg/day (chronic non-cancer) 

Fish consumption exposure – 

 Average Daily Dose (ADD) = 

 7.2E-07 mg/kg/day (chronic non-cancer)
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(4) Reliability Score 2 (Reliable with restrictions) The model has not been validated but is sufficiently 

conservative and accepted by authorities. Appropriate inputs have been used reflecting best available 

information and conservative estimates where applicable. 

(5) Remarks 

The aquatic NOEC = 270 μg/L. The estimated median and 7Q10 (low flow) exposures are 0.099 and 1.3 

μg/L, respectively. 

The NOAEL chosen for LAS for this assessment is 85 mg/kg/day. Estimated exposures in consumer 

products under 50th percentile conditions are 1.9E-06 mg/kg/day and 7.2E-07 mg/kg/day for drinking water 

and fish consumption, respectively. 
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Format C: Modeling Evaluation #3

I. Identification Information

(1) Activity associated with Modeling Information 

Dermal Exposures from Use of Consumer Products 

II. Modeling Objective

(1) Modeling Study Objective 

To provide estimates of human dermal exposure (in daily dose, i.e., mg/kg/day) to the general population 

from use of consumer products containing LAS. 

(2) Description of Modeled Scenario 

Dermal exposures to LAS that are modeled include: 

Exposure during the activity/use of products --

Laundry detergent: hand washing laundry 

Laundry detergent: pretreatment 

Dishwashing liquid detergents: hand washing dishes 

Dishwashing liquid: hand washing hands 

Hard surface cleaners (diluted and undiluted) 

Exposure from residuals on clothing – 

Laundry detergents on clothing following washing 

Fabric conditioner on clothing 

Exposure from residuals after using products

Face and hand soap (bars) 
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III. Description of Model and Status of Peer Review and Validation 

(1) Tool or Model 

The modeling presented here uses simple, first principle equations, which err on the side of being 

protective.

 General Exposure Model

 Potential Chemical Exposure (PE) = 

Exposure to Product (EXP) x Chemical Concentration in Product Formulation (PF) 

Dermal Route – Product Specific Models

1. Exposure during the activity/use of diluted and undiluted laundry and dishwashing 

products, and diluted and undiluted hard surface cleaning products 

[FQ x CA x PC x FT x CF x TF x DA] x PF 

BW 

2. Exposure to laundry and fabric conditioning product residual on clothing 

[A x PR x PT x DA x CF] x PF 

BW 

 [“FQ” frequency of use is 1 wash load/day for clothing] 

 3. Exposure to face and hand soap residual after use 

[FQ x A x PR x DA x CF] x PF 

BW 

Where: 

FQ: frequency of use (use/day) 

CA: body surface contact area (cm2

) 

PC: product concentration (g/cm3

) 

FT: film thickness on skin (cm) 

CF: conversion factor (1000 mg/g) 

TF: time scaling factor (unitless) 

DA: dermal absorption (%) 

BW: female body weight (kg) 

PF: LAS concentration in product formulation (%) 

A: amount per use (g/day or g/wash) 

T: transfer to skin (%) 

PR: percent retained on clothing or on skin (%) 

PT: percent transferred from clothing to skin (%) 

(2) Validation/Peer Review 

These exposure calculations use first principle equations and are mathematically consistent with the EPA 

Exposure Guidelines (1992) with regard to modeling dermal doses. 

(3) Availability and Documentation 

USEPA 1992. Guidelines for Exposure Assessment. [FRL-4129-5] 
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IV. Inputs, Outputs, and Quality Description 

(1) Media Modeled 

The exposure media are the LAS-containing products used by consumers. The LAS Coalition fielded a 

survey among producers and formulators to establish the range of LAS concentrations in each of the product 

forms. For each product category containing LAS, the minimum and maximum of the range were utilized as 

inputs for the dermal exposure models. 

(2) Inputs 

The dermal exposure scenarios encompass conservative, screening-level inputs including: the high-end 

frequency of product use, the high-end amount of product per use, the high-end percent of product retained 

on skin or clothes following use. Also, actual dermal absorption is only about 1% of product (Schaefer and 

Redelmeier 1996), whereas all modeled exposures include a default assumption of 100%. Thus, the modeled 

exposure is conservative by a factor of at least 100 based on absorption alone. LAS coalition member 

companies provided formulation information on the range of LAS concentrations in specified product types 

to be used in this assessment.

Exposure during the activity/use of diluted and undiluted laundry and dishwashing products, 

and diluted and undiluted hard surface cleaning products 

[FQ x CA x PC x FT x CF x TF x DA] x PF 

BW 

Laundry 

Pretreatment 

(diluted) 

Neat 

Laundry 

Pretreatment 

(undiluted) 

Handwash of 

Laundry 

(diluted) 

Handwash of 

Dishes 

(diluted) 

Handwash of 

hands 

with dish 

liquid 

(diluted) 

Hard 

Surface 

Cleaners 

(diluted) 

Hard 

Surface 

Cleaners 

(undiluted) 

Frequency (FQ) 

(use/day) 1 h

 1 h 1 h 3 h 0.14 h 1 h 1 h

Contact Area (CA) 

(cm2

) 360 b

 360 b 1680 f 1680 f 1680 f 1680 f 180 j

Product 

Concentration 

(PC) (g/cm3

) 

0.6 a 1 a 0.01 a

 0.0015 a 0.9 g 0.01 a 1 a

Film Thickness 

(FT) (cm) 0.0024 c 0.0024 c 0.0024 c

 0.0024 c 0.0024 c 0.0024 c 0.0024 c

Conversion Factor 

(CF) (1000 mg/g) 1000 1000 1000 1000 1000 1000 1000 

Time Scaling 

Factor (TF) 

(unitless) 

0.007 d

 0.007 d 0.007 d 0.03 d .00035 d 0.014 h 0.014 h

Dermal Absorption 

(DA) (%) 100% i

 100% i 100% i 100% i 100% i 100% i 100% i

Female body 

weight (BW) (kg) 60 e

 60 e 60 e 60 e 60 e 60 e 60 e

LAS concentration 

in product 

formulation (PF) g 

(%) 

5-10% 5-10% 1-25% 5-25% 5-25% 1-5% 1-5% 

References: 

a: LAS Coalition survey 

b: Palms surface area (EPA Exposure Factors Handbook) 

c: EPA 560/5-85-007, Methods of assessing exposure to chemical substances, Vol.7, Versar, 1985 

d: HERA project 

e: Female body weight (EU Technical Guidance Document, 1996) 

f: Hands and forearms (EPA Exposure Factors Handbook) 

g: LAS Coalition survey, Min-Max values 

h: SDA Habit and Practice Survey 
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i: Default assumption 

j: Surface area of the palm of one hand (EPA Exposure Factors Handbook) 

Exposure to laundry and fabric conditioning product residual on clothing 

[A x PR x PT x DA x CF] x PF 

BW 

Liquid 

Laundry 

Detergent 

Dry Laundry 

Detergent 

Tablet 

Laundry 

Detergent 

Fabric 

conditioner 

(dryersheet) 

Amount Per Use (A) (g/day or g/wash) 121 a

 121 a 135a 3 a 

Percent Retained on Clothing (PR) (%) 1% a 1% a 1% a 10% a

Percent Transferred from Clothing to Skin 

(PT) (%) 1% a 1% a 1% a 1% a

Dermal Absorption (DA) (%) 100% b 100% b 100% b 100% b

Conversion Factor (CF) (1000 mg/g) 1000 1000 1000 1000 

Female body weight (BW) (kg) 60 c 60 c 60 c 60 c

LAS concentration in product formulation 

(PF) g (%) 1-25% d

 5-25% d 5-25% d 0.1 – 0.5% d

 References: 

 a: SDA Habit and Practice Survey 

 b: Default assumption 

 c: EU Technical Guidance Document, 1996

 d: LAS Coalition Survey, Min-Max values 

Exposure to face and hand soap residual after use 

[FQ x A x PR x DA x CF] x PF 

BW 

Bar Soap 

Hand 

Bar Soap 

Face 

Frequency of Use (FQ) (use/day) 6 a 1 a

Amount Per Use (A) (g/use) 0.36 a 0.27 a

Percent Retained on Skin (PR) (%) 1% e 1%e

Dermal Absorption (DA) (%) 100% b 100%b

Conversion Factor (CF) (1000 mg/g) 1000 1000 

Female body weight (BW) (kg) 60 c 60 c

LAS concentration in product formulation (PF) g (%) 1-5% d 1-5% d 

 References: 

 a: SDA Habit and Practice Survey 

 b: Default assumption 

 c: EU Technical Guidance Document, 1996

 d: LAS Coalition Survey, Min-Max values 

 e: CTFA 2003 data 

 

(3) Model Outputs 

Exposure during the activity/use of diluted and undiluted laundry and dishwashing products and 

diluted and undiluted hard surface cleaning products 

 

Potential Dermal Exposure 

(mg/kg/day) a

Laundry Pre-Treatment (diluted) 3.0E-3 to 6.0E-3 

Neat Laundry Pre-Treatment (undiluted) 5.0E-3 to 1.0E-2 

Hand-wash of Laundry (diluted) 4.7E-5 to 1.2E-3 
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Hand-wash of Dishes (diluted) 5.0E-4 to 2.3E-3 

Hand-wash (dishwashing liquids) of hands 

(diluted) 1.0E-4 to 7.4E-4 

Hard Surface Cleaners (diluted) 1.0E-3 to 5.0E-4 

Hard Surface Cleaners (undiluted) 5.0E-3 to 1.0E-3 a range based on minimum and maximum product concentration values 

Exposure to laundry and fabric conditioning product residual on clothing 

 

Potential Dermal Exposure 

(mg/kg/day) a

Liquid Laundry Detergent 2.0E-3 to 5.0E-2 

Dry Laundry Detergent 1.0E-2 to 5.0E-2 

Tablet Laundry Detergent 1.1E-2 to 5.6E-2 

Fabric conditioning (dryer sheets) 5.0E-5 to 3.0E-4 a range based on minimum and maximum product concentration values 

Exposure to face and hand soap residual after use 

 

Potential Dermal Exposure 

(mg/kg/day) a

Bar Soap – Hand 3.6E-3 to 1.8E-2 

Bar Soap - Face 5.0E-4 to 2.3E-3 a range based on minimum and maximum product concentration values 

(4) Reliability Score 1 (Reliable without restrictions) The models used are first principle equations, 

which are sufficiently conservative, have undergone peer review and are generally accepted by authorities. 

Appropriate inputs have been used, reflecting best available information and conservative estimates where 

applicable. 

 (5) Remarks 

An appropriate NOAEL from animal studies for use as a comparison is 85 mg/kg. Estimated 

dermal exposures in consumer products range from a low of 0.000047 to a high of 0.056 

mg/kg/day. 

These human exposure evaluations include conservative (protective) input and model assumptions (e.g. all 

modeled exposures are conservative by a factor of at least 100 due to use of a default assumption of 100% 

absorption vs. a measured value of <1%). 
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Annex 1 References 

Battelle, Inc. 1999. Measurement and characterization of aerosols generate from a consumer spray 

product-pilot study. Final report to the Soap and Detergent Association. Battelle Study No. 

N003043A. January. 

Cavalli, L., Clerici, R., Radici, P., and Valtorta, L. 1999. Update on LAB/LAS. Tenside Surf. Det. 

36:254-258. 

Colin A. Houston. 2002. Surfactant Developments. Forecast to 2010. A Multiclient Study. Colin A. 

Houston & Associates, Inc., August 2002. 

CTFA. 2003. Cosmetics, Toiletries, and Fragrance Association. 

Dunphy, J., Federle, T.W., Itrich, N., Simonich, S., Kloepper-Sams, P.K., Scheibel, J., Cripe, T., 

and Matthijs, E. 2000. Environ. profile of improved alkyl benzene surfactants. 5th Cesio World 

Surfactants Congress, Firenze, Italy. V.2:1489-1497. 

EU Technical Guidance Document. 1996. Technical Guidance Document in Support of 

Commission Directive 93/67/EEC on Risk Assessment for New Notified Substances and 

Commission Regulation (EC) No 1488/94 on Risk Assessment for Existing Substances. Part I. 

Appendixes IV-VI. 

HERA. 2004. Linear Alkylbenzene Sulphonate, LAS. Human & Environmental Risk Assessment 

on ingredients of European household cleaning products. Version 2.0, May 2004. 

http://www.heraproject.com/RiskAssessment.cfm

HERA. 2002. Guidance Document Methodology, April 2002. 

http://www.heraproject.com/RiskAssessment.cfm

LAS Coalition Survey. 2002. Survey of use and exposure information provided by the member 

companies of the Industry Coalition for the SIDS Assessment of LAS. 

McAvoy, D.C., Eckhoff, W.S., and Rapaport, R.A. 1993. Fate of linear alkylbenzene sulfonate in 

the environment. Environ. Toxicol. Chem. 12:977-987. 

Nielsen, A.M., Britton, L.N., Beall, C.E., McCormick, T.P., and Russel, G.L. 1997. Biodegradation 

of co-products of commercial LAS. Environ. Sci. Technol. 31:3397-3404. 

Schaefer, H. and Redelmeier, T.E. 1996. Skin barrier. Principles of percutaneous absorption, S. 

Karger AG, P.O. Box, CH-4009 Basel (Switzerland), ISBN 3-8055-6326-4. As cited in HERA 

2004. 

SDA Habit and Practice Survey. 2002. Survey conducted by the Soap and Detergent Association 

and its member companies. 

Tabor, C.F. and Barber, L.B., II. 1996. Fate of linear alkylbenzene sulfonate in the Mississippi 

River. Environ. Sci. Technol. 30:161-171. 

Tolls, J., Haller, M., DeGraaf, I., Thijssen, M.A.T.C., and Sijm, D.T.H.M. 1997. Bioconcentration 

of LAS: experimental determination and extrapolation to environmental mixtures. Environ. Sci. 

Technol. 31:3426-3431. 

USEPA. 1985. Methods of assessing exposure to chemical substances. Vol. 7, Versar. EPA 560/5-

85-007. 

USEPA. 1987. Exposure Factors Handbook, August 1987. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 91

USEPA 1992. Guidelines for Exposure Assessment. [FRL-4129-5] 

USEPA. 2002. EFAST, beta release. Office of Pollution Prevention and Toxics. US Environmental 

Protection Agency. www.epa.gov/oppt/exposure/docs/efast.htm

Valtorta, L., Radici, P., Calcinai, D., and Cavalli, L. 2000. Recent developments of LAB/LAS. Riv. 

It. Sostanze Grasse. LXXVII:73-76. 

Versteeg, D.J. and Rawlings, J.M. 2003. Bioconcentration and toxicity of dodecylbenzene sulfonate 

(C12LAS) to aquatic organisms exposed in experimental streams. Arch. Environ. Contam. Toxicol. 

44:237-246. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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Annex 2 – Commercial LAS (C11.6 – C11.8) Acute Toxicity Data 

This Annex provides the results of an extensive review of the data previously compiled by BKH 

(1993) and of the published and unpublished literature since this data compilation (HERA 2004). 

The purpose of this review is to identify the lowest valid acute toxicity values on commercially 

representative LAS, having average alkyl chain lengths of C11.6 to 11.8 (Table, SIAR Section 1.1). 

Valid studies on commercial LAS on test species for which there are OECD acute toxicity 

guidelines are listed in the tables below. References to the published studies follow the tables. 

Studies that were not valid, or were not conducted on commercial LAS, are listed in the table of 

rejected studies along with the reasons for rejection. 

Lowest valid values for each taxon are identified in the table. Robust summaries of these studies 

are included in the dossier. The location of other studies provided in the dossier are noted under 

Remarks. 

Note that all non GLP studies date before the implementation of OECD GLP guidelines. Studies 

noted as QA are those whose report mentioned a specific Quality Assurance program. 
OECD SIDS LINEAR ALKYLBENZ

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Fish, 96h. Lepomis macrochirus 

Reference and 

year 

LC50 

(mg/L) 

Lab Test 

Procedure 

GLP Static/flow 

through 

# replicates Indiv./rep. Nominal conc 

(mg/L) 

Test T 

range (oC) 

Hard. (mg 

CaCO3/L) 

Measured 

conc. 

Con

mort

1. 22852, P&G 

1979 

3.7 Bionomics US EPA 

1975 

EPA-660/3-

75-009 

QA Static 3 10 Control, 1.3, 2.2, 

3.6, 6.0, 10 

22±1 43 Nominal conc 

active 

0% 

2. 23613,P&G 

1980 

4.4 UCES US EPA 

1975 

EPA-660/3-

75-009 

QA Static Not reported 10 Control, 0.86, 1.4, 

2.4, 4.0, 6.7 

20-23 30 Nominal conc 

active 

0% 

3. 23612, P&G 

1980 

4.6 Bionomics US EPA 

1975 

EPA-660/3-

75-009 

QA Static 3 10 Control, 0.78, 1.3, 

2.2, 3.6, 6.0, 10 

22±1 48 Nominal conc 

active 

0% 

4. 23617, P&G 

1980 

4.6 Bionomics US EPA 

1975 

EPA-660/3-

75-009 

QA Static 3 10 Control, 0.78, 1.3, 

2.2, 3.6, 6.0, 10 

22±1 45 Nominal conc 

active 

0% 

5. 23722, P&G 

1980 

4.6 UCES US EPA 

1975 

EPA-660/3-

75-009 

QA Static 5 10 Control, 1.0, 1.8, 

3.2, 5.6, 10 

21-22 38 Nominal conc 

active 

0% 

6. 22824, P&G 

1978 

6.3 UCES US EPA 

1975 

EPA-660/3-

75-009 

No Static Nortreported 10 Control, 1.4, 2.2, 

3.6, 6.0, 10 

22±0.5 46 Nominal conc 

active 

0% 

7. 28661, P&G 

1982 

6.4 Biospherics US EPA 

1975 

EPA-660/3-

75-009 

QA Static Nortreported 10 

Control, 01.3, 2.2, 

3.6, 6.0, 10 21-22 47 Nominal conc 

active 

0% 

8. 27917, P&G 

1980 

7.7 Bionomics US EPA 

1975 

EPA-660/3-

75-009 

No Static 3 10 Control, 1.3, 2.2, 

3.6, 6.0, 10 

22±1 42 Nominal conc 

active 

0% 
OECD SIDS LINEAR ALKYLBENZ

UNEP PUBLICATIONS 

Reference and 

year 

LC50 

(mg/L) 

Lab Test 

Procedure 

GLP Static/flow 

through 

# replicates Indiv./rep. Nominal conc 

(mg/L) 

Test T 

range (oC) 

Hard. (mg 

CaCO3/L) 

Measured 

conc. 

Con

mort

9. 23603, P&G 

1979 

7.1 UCES US EPA 

1975 

EPA-660/3-

75-009 

QA Static Not reported 10 Control, 1.0, 1.8, 

3.2, 5.6, 10 

20.5-21 42 Nominal conc 

active 

0% 

10. Lewis and Perry, 1981 

1.67 US EPA 

1975 

EPA-660/3-

75-009 

No Static Not reported 10 22±1 137 Nominal conc 

active 

Fish, 96h. Pimephales promelas 

Reference and 

year 

LC50 

(mg/L) 

Lab Test Procedure GLP Static/flow 

through 

# replicates Indiv./rep. Nominal conc 

(mg/L) 

Test T range 

(oC) 

Hard. (mg 

CaCO3/L) 

Measured 

conc. 

Cont

morta

11. Holman and 

Macek, 1980 

4.1 US EPA 1975 

EPA-660/3-75-

009 

No 40 MBAS 
OECD SIDS LINEAR ALKYLBENZ

UNEP PUBLICATIONS 

Daphnia magna: 48 h 

Reference and year LC50 

(mg/L) 

Lab Test 

Procedure 

GLP Static/flow 

through 

# replicates Indiv./rep Nominal conc Test T 

range 

(oC) 

Hard. (mg 

CaCO3/L) 

Measured 

conc. 

Control 

mortality 

12. 23618, P&G 

1980 

4.4 Bionomics US EPA 

1975 

EPA-660/3-

75-009 

QA Static 3 5 Control, 0.78, 

1.3, 2.2, 3.6, 

6.0, 10 

21-22 175 nominal 

active 

0% 

13. 22853, P&G 

1979 

4.9 Bionomics US EPA 

1975 

EPA-660/3-

75-009 

No Static 3 5 Control, 1.4, 

2.2, 3.6, 6.0, 

10 

22±1 162 nominal 

active 

0% 

14. 23611,P&G 

1980 

7.1 UCES US EPA 

1975 

EPA-660/3-

75-009 

QA Static 4 5 Control, 1.9, 

3.2, 5.4, 9.0, 

15 

21-22 220 nominal 

active 

0% 

15. 28793, P&G 

1982 

9.3 Biospherics US EPA 

1975 

EPA-660/3-

75-009 

No Static 4 10 Control, 4.9, 

6.1, 9.6, 12, 15 

20.5-21 120 nominal 

active 

2.5% 

16. Taylor, 1985 4.6 US EPA 

1975 

EPA-660/3-

75-009 

No Static 3 5 21±1 300 Nominal 

17. Lewis and Perry, 

1981 

3-5.6 US EPA 

1975 

EPA-660/3-

75-009 

No Static 3 5 Measured 

as MBAS 

18. Lewis and 

Suprenant, 1983 

1.8-5.6 US EPA 

1975 

EPA-660/3-

75-009 

No Static Nominal 

19. Maki and Bishop, 

1979 2.5-4.3 US EPA 

1975 

EPA-660/3-

75-009 

No Static 3 5 21±1 120 Measured 

as MBAS 
OECD SIDS LINEAR ALKYLBENZ

UNEP PUBLICATIONS 

Reference and year LC50 

(mg/L) 

Lab Test 

Procedure 

GLP Static/flow 

through 

# replicates Indiv./rep Nominal conc Test T 

range 

(oC) 

Hard. (mg 

CaCO3/L) 

Measured 

conc. 

Control 

mortality 

20. Lewis, 1983 4.8 ASTM No Static 3 5 131 Measured 

as MBAS 

21. Verge & Moreno, 

2000 

6.3 OECD 202, 

1984 

No Static 4 5 20±1 200 Nominal 

22. Hooftman and van 

DrongelenSevenhuijsen 1990 

1.62 TNO OECD 202, 

1984 

Yes Static 4 5 Control, 3.2, 

5.6, 10, 18, 32, 

56, 100 

20±1 Measured 

Algae, Selenastrum capricornutum and Scenedesmus subspicatus

Reference and 

year 

ErC50 

(mg/L) 

Exposure 

period 

Test species Lab Test Procedure GLP # replicates # cells./rep Nominal conc., 

mg/L 

Test T 

range 

(oC) 

Hard. (mg 

NaHCO3/

L) 

Measu

con

23. 43235, 

P&G 

1991 

35.5 96 Hr Selenastrum 

capricornutum 

Bionomics OECD 201 Yes Duplicate tests and quadriuplicate 

controls 

104

cells/ml 

Control, 1.0, 3.1, 10, 

32, 99, 180, 320, 

560 

21-22 150 measu

24. Lewis, 

1986; Lewis 

and Hamm, 

1986 

29 96 Hr Selenastrum 

capricornutum 

ASTM, 1984 No 21.2-

25.6 

137 

25. Verge and 

Moreno, 1996 

163 72 Hr Scenedesmus 

subspicatus 

OECD, 1984 No Triplicate test 

concentrations and six control replicates 

104 21-22 Nomi

26. Scholz, 

1992 

127.9 72 Hr Scenedesmus 

subspicatus 

Dir 

88/302/EEC, 

1988 

Yes 20,000 

cells/ml 

Control, 0.6, 2.4, 10, 

40, 160 

24+/-2 Nomi

27. Scholz, 

1994 

82 72 Hr Scenedesmus 

subspicatus 

Dir 92/69/EEC, 

1992 

Yes 20,000 

cells/ml 

Control, 0.1, 0.4, 

1.6, 6.4, 25, 160 

24+/-2 Nomi
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 97

List of Published References 

10. Lewis, M.A., and Perry, R.L., 1981; Acute Toxicities of Equimolar and Equitoxic Surfactant 

mixtures to Daphnia magna and Lepomis macrochirus. 

11. Holman, W. and Macek, K., 1980; An aquatic safety assessment of Linear Alkylbenzene 

Sulfonate (LAS): Chronic effects on Fathead minnows. Transactions of the American Fisheries 

Society 109, 122-131. 

16. Taylor, M.J.; Effect of Diet on the Sensitivity of Daphnia magna to Linear Alkylbenzene 

Sulfonate, Aquatic Toxicology and Hazard Assessment: Seventh Symposium, ASTM STP 854, 

R.D. Cardwell, R. Purdy, and R.C. Bahner, Eds, American Society for Testing and Materials, 

Philadelphia, 1985, pp 53-72. 

17. Lewis, M.A., and Perry, R. L.,1981; Acute Toxicities of Equimolar and Equitoxic Surfactant 

Mixtures to Daphnia magna and Lepomis macrochirus. Aquatic Toxicology and Hazard 

Assessment: Fourth Conference, ASTM STP 737, D. R. Branson and K.L. Dickson, Eds, American 

Society for Testing and Materials, 1981, pp 402-418. 

18. Lewis, M.A. and Suprenant, D.,1983; Comparative Acute Toxicities of Surfactants to Aquatic 

Invertebrates. Ecotoxicology and Environmental Safety, 7, 313-322 (1983). 

19. Maki, A. and Bishop, W., 1979; Acute Toxicity Studies of Surfactants to Daphnia magna and 

Daphnia pulex. Arch. Environm. Contam. Toxicol. 8, 599-612 (1979). 

20. Lewis, M.A., 1983; Effect of loading density on the acute toxicities of Surfactants, Copper, and 

Phenol to Daphnia magna Straus. Arch. Environ. Contam. Toxicol. 12, 51-55. 

21. Verge, C. and Moreno A.; 2000; Effect of Anionic Surfactants on Daphnia magna. Tenside 

Surf. Det. 37 (2000) 3. 

24. Lewis, M.A., 1986; Comparison of the effects of surfactants on freshwater phytoplankton 

communities in experimental enclosures and on algal population growth in the laboratory. Environ. 

Toxicol. Chem., Vol. 5, pp 319-322; Lewis, M.A., and Hamm, B.G., 1986; Environmental 

modification of the photosynthetic response of lake plankton to surfactants and significance to a 

laboratory-field comparison. Water Res. 20:1575-1582. 

25. Verge, C., and Moreno A., 1996; Toxicity of anionic surfactants to green microalgae 

Scenedesmus subspicatus and Selenastrum capricornutum. Tenside Surf. Det. 33 , 166-169. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 98

List of Rejected References 

Paper Reason 

Fish – Lepomis macrochirus

Dolan and Hendricks, 1976. The lethality of and 

intact and degraded LAS mixture to bluegill 

sunfish and a snail. Journal WPCF, Vol. 48, 

No.11, November 1976, pp.2570-2577. 

Test product is not commercial LAS (C13 

sulfonic acid) 

Procter & Gamble 22581, 28361, 1991; dossier 

4.1(n) 

Study not available 

Fish – Pimephales promelas 

Kimerle and Swisher, 1977; dossier 4.1(r) Test product is not commercial LAS 

(C13.3); exposure period 48 Hr 

Swisher et al., 1978; dossier 4.1(p) Test product is not commercial LAS (C11.1) 

McKim, Arthur and Thorslund, 1979. Toxicity of 

a Linear Alkylate Sulphonate detergent to larvae 

of four species of freshwater fish. Bull. Environ. 

Contam. Toxicol., 14(1), 1-7. 

Test product is not commercial LAS; it is a 

detergent formulation 

Macek and Sleight, 1977. Utility of toxicity tests 

with embryos and fry of fish in evaluating hazards 

associated with the chronic toxicity of chemicals 

to fishes. Aquatic Toxicology and Hazard 

Evaluation, ASTM STP 634, P.L. Mayer and J.L. 

Hamelink, Eds., American Society for Testing and 

Materials, 1977, pp. 137-146. 

Fish were larvae, not the age recommended 

in OECD Method 

Daphnia magna 

Hüls, 1986. 7/86, N. Sholz, unpublished LC50 24 Hr determined for Daphnia magna

Maki, 1979. Correlations between Daphnia magna

and Fathead minnow (Pimephales promelas) 

Chronic Toxicity values for several classes of test 

substances. J. Fish.Res. Board Can., vol 36, 1979, 

pages 411-420. 

Chronic test 

Kimerle and Swisher, 1977; dossier 4.2A(g) Test product is not commercial LAS (C13.3) 

Canton and Sloof, 1982. Substitutes for phosphate 

containing washing products: their toxicity and 

biodegradability in the aquatic environment. 

Chemosphere, Vol.11, No.9, pp 891-907. 

Test product is not commercial LAS (C11) 

 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 99

Barera and Adams, 1983. “Resolving some 

practical questions about Daphnia Acute Toxicity 

Tests”. Aquatic Toxicology and Hazard 

Assessment: Sixth Symposium, ASTM STP 802, 

W.E. Bishop, R.D. Cardwell and B.B. Heidolph, 

Eds. American Society for Testing and Materials, 

Philadelphia, 1983, pp 509-518. 

Test product is not commercial LAS (C13.3) 

Lal , Misra, Viswanathan and Murti, 1983. 

Comparative studies on Ecotoxicology of 

Synthetic Detergents. Ecotoxicology and 

Environmental Safety, 7, 538-545. 

Test product not specified 

Mode of culturing Daphnia not clear 

Test method not specified 

Test conditions not clearly explained 

Calculations not clear. Median Tolerance 

Limit is the parameter assessed. 

Gard-Terech and Palla, 1986. Comparative 

kinetics study of the evolution of freshwater 

aquatic toxicity and biodegradability of linear and 

branched alkylbenzene sulfonates. Ecotoxicology 

and Environmental Safety 12, 127-140 (1986). 

Toxicity determined for effluent of 

biodegradation test 

Huels, unpublished; dossier 4.2A(d) Study not available 

Procter & Gamble, 1991, 23276; dossier 4.2A(f) Study conducted as part of QA program to 

qualify various labs and the result is not 

considered reliable 

Algae 

Canton and Sloof, 1982. Substitutes for phosphate 

containing washing products: their toxicity and 

biodegradability in the aquatic environment. 

Chemosphere, Vol.11, No.9, pp. 891-907. 

Test product is not commercial LAS (C11) 

Henkel, unpublished (Registry No. 5929) ; dossier 

4.3(h) 

Study not available 

Huls AG, 1/90 N. Scholz; dossier 4.3(i) Study not available 

Procter & Gamble AL/12, 1991; dossier 4.3(j) Mis-cited; not available and not a P&G 

study 

Procter & Gamble 29101, 1991; dossier 4.3(k) Mis-cited; values and protocol do not match 

report; report invalid 

Procter & Gamble AL/10, 1991; dossier 4.3(l) Mis-cited; not available and not a P&G 

study 

Procter & Gamble P2636.01, 1991; dossier 4.3(m) Test product is not commercial LAS (C12.3) 

Yamane et al., 1984; dossier 4.3(n) Exposure period: 48 Hr 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 100

ANNEX 3 – DERIVATION OF THE HC5 VALUE 

Linear Alkylbenzene Sulfonate (LAS) 

Industry Coalition for the SIDS Assessment of LAS 

Introduction 

Extrapolation procedures are commonly used to evaluate the available laboratory-generated singlespecies toxicity test data. For data sets in which toxicity data are available for a reasonably large 

number of species, the species sensitivity distribution approach is often used. In this approach, the 

concentration protection of most single species (generally 5%, i.e., 95% of the species NOECs are 

greater) is calculated. This value, called the HC5, is the lower 5th percentile of a distribution of 

single-species NOEC tests and thus is protective of the environment (Aldenberg and Slob 1993). 

For the current evaluation of LAS data, the HC5 for aquatic species was calculated for LAS using 

the available single-species chronic freshwater data including the data summarized by van de 

Plassche et al. (1999). 

Method 

The van de Plassche et al. (1999) data were analyzed using several types of distributions as 

described in Versteeg et al. (1999). The goodness-of-fit for each distribution was evaluated by the 

one-sample Cramer-vom Mises statistical test, which was used to compare the relative goodness-offit with the various distributions. Based on higher p-values, the log-logistic distribution was a better 

fit to the data than the log normal distribution used by van de Plassche et al. (1999). 

Consequently, the available chronic data and the van de Plassche et al data were plotted using loglogistic distributions. The fitted NOEC distribution is shown by the solid line in the distribution 

function. Lower 95% confidence limits on the fitted NOEC distribution function (dashed lines) 

were calculated analogous to the methods of Aldenberg and Slob (1993), with the exception that 

here the maximum likelihood estimators were used as opposed to moment estimators to measure 

goodness-of-fit. The maximum likelihood estimators are generally less biased and have better 

precision than moment estimators (Schafer and Sheffield 1973). 

The Kolmogorov-Smirnov (K-S) statistical test was used to determine the goodness-of-fit and 

calculate the HC5 (HC5, 50% confidence interval) value. 

The available chronic toxicity data and the data of van de Plassche et al. (1999) are presented in 

Table 12A of this SIAR. For Microcystis aeruginosa, dossier 4.3s, the NOEC was calculated by 

dividing the EC50 value by 3. As documented below (data from BKH 1993), the average 

EC50/NOEC ratio for LAS is 3, and thus this calculation of the NOEC value from the EC50 is 

supported by a large database of information. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 101

All NOEC values were normalized to C11.6 as this was considered the structure most typically 

produced and used globally. The normalization procedure (van de Plassche et al. 1999) was based 

on the use of quantitative structure-activity relationships (QSARs). Since no long-term QSARs 

were available for LAS, QSARs for short-term toxicity were used. Normalization was carried out 

using the following procedure. 

The log Kow was calculated for C11.6 LAS and the tested structure using the Leo and Hansch method 

(1979) with the modification for phenyl isomer position by Roberts (1991), which calculates log 

Kow values for LAS using a position-dependent branching factor (PDBF). An increment of 0.54 is 

used for a CH2 unit (Leo and Hansch 1979). 

The EC50 values were calculated using the following QSAR for LAS: 

 Log(1/EC50) = 0.63 log Kow + 2.52 

The ratio between the predicted EC50s for the normalized and the tested structure was calculated. 

The NOEC of the tested structure was then multiplied by this ratio to obtain the NOEC for the 

normalized structure. The normalized NOECs were then used to calculate the geometric mean for 

each species for which data were available. 

For example, for a NOEC of 0.9 mg/L for C12.6 LAS, the procedure is as follows. The calculated 

log Kow and molecular weight for C12.6 LAS are 3.86 and 356, respectively. Using the QSAR given 

above, this leads to an EC50 of 4.0 mg/L. For C11.6 LAS, the calculated log Kow and molecular 

weight are 3.32 and 342, respectively, leading to an EC50 of 8.4 mg/L. The ratio between the 

predicted EC50 values for C11.6 LAS and C12.6 LAS is 2.1. Multiplying the NOEC of 0.9 mg/L by 

2.1 leads to a normalized NOEC of 1.9 mg/L for C11.6 LAS. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 102

Results 

The single-species chronic toxicity data summarized by van de Plassche et al. (1999) resulted in a 

calculated HC5 value of 0.32 mg/L. This value is based on a fit of the data to a log-normal 

distribution. Using the goodness-of-fit comparisons as described above, the best fit with the van de 

Plassche et al. data was found with the log-logistic distribution (Versteeg et al. 1999). A HC5 value 

of 0.36 mg/L was determined for C11.6 LAS with the log-logistic distribution. The data used 

(“Original VdP Values”), the cumulative probability distribution of the data and the HC5 calculation 

are shown below. 

These same methods were also applied to the available chronic data provided in the dossier and 

summarized in Table 12A of this SIAR. Using the log-logistic distribution of the normalized 

NOEC data, the HC5 value calculated is 0.24 mg/L. The data used (“Available Chronic Values”), 

the cumulative probability distribution of the data and the HC5 calculation are shown below. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 103

Original VdP 

Values (Table 12A)

NOEC 

(mg/L) Available Chronic Values NOEC (mg/L) 

 

Fish Fish 

Brachydanio rerio 2.3 (No valid study identified) 

(Not reviewed by van 

de Plassche et al.) Lepomis macrochirus, dossier 4.5.1m 1 

Oncorhynchus mykiss 

(geometric mean) 0.34 (No valid study identified) 

Pimephales promelas 

(geometric mean) 0.87 Pimephales promelas, geometric mean 1.3* 

Poecilia reticulata 3.2 (No valid study identified) 

Tilapia mossambica 0.25 Tilapia mossambica, dossier 4.5.1e 0.25 

 

Aquatic 

Invertebrates Aquatic Invertebrates 

Ceriodaphnia sp. 3.2 Ceriodaphnia sp., dossier 4.5.2b 0.84 

Chironomus riparius 2.8 Chironomus riparius, dossier 4.5.2o 2.87 

Daphnia magna 

(geometric mean) 1.4 Daphnia magna, geometric mean 1.83* 

Paratanytarsus 

parthenogenica 3.4 Paratanytarsus parthenogenica, dossier 4.5.2h 3.4 

 

Algae Algae 

Chlamydomonas 

reinhardi 12 (No valid study identified) 

Chlorella kessleri 3.5 (No valid study identified) 

Microcystis sp. 

(geometric mean) 0.8 Microcystis aeruginosa, dossier 4.3s 0.3** 

Plectonema boryanum 15 (No valid study Identified) 

Scenedesmus 

subspicatus 

(geometric mean) 7.7 Scenedesmus subspicatus, geometric mean 6.1* 

Selenastrum 

capricronutum 

(geometric mean) 3.8 Selenastrum capricronutum, dossier 4.3a 0.58* 

 

Higher Plants Higher Plants 

(Not reviewed by van 

de Plassche et al.) Elodea canadensis, dossier 4.3o 4 

(Not reviewed by van 

de Plassche et al.) Lemna minor, dossier 4.3p 1.1 

*Geometric mean of available valid studies (see Table 12A) 

** EC50/3 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 104

Available Chronic Data Distribution 

Original VdP Values 

Log-Logistic Calculation 

Compound Group Statistical Parameters 

 Intercept (u) Scale (sigma) 

 (mean) Variability K-S Test p-value HC5 

Available Chronic Values 0.279 0.5736 0.9756 0.244 

Original VdP Values 0.911 0.6531 0.8655 0.363 

NOEC (mg/L)

Cumulative Probability

0.01 0.10 1.00 10.00 100.00

0.0

0.2

0.4

0.6

0.8

1.0

 Tilapia

 Microcystis

 Selenastru,

 Ceriodaphnia

 Lepomis

 Lemna

 Pimephales

 Daphnia

 Chironomus

 Partanytarsus

 Elodea

 Scenedesmus

LAS

NOEC (mg/L)

Cumulative Probability

0.01 0.10 1.00 10.00 100.00 1000.00

0.0

0.2

0.4

0.6

0.8

1.0

 Tilapia mossambica, dossier 4.5.1e

 Oncorhynchus

 Microcystis

 Pimephales promelas, dossier 4.5.1b

 Daphnia magna, dossier 4.5.2b

 Brachydanio rerio, dossier 4.5.1a

 Chironomus riparius, dossier 4.5.2m

 Poecilia reticulate, dossier 4.5.1c

 Ceriodaphnia

 Paratanytarsus parthenogenica, dossier 4.5.2g

 Chlorella kessleri, dossier 4.3r

 Selenastrum capricronutum, dossier 4.3a

 Scenedesmus subspicatus, dossier 4.3f

 Chlamydomonas

 Plectonema

Original VdP
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 105

Discussion 

The HC5 values for LAS are considered to be valid estimates of the NOEC since all three meet the 

OECD criteria for statistical extrapolation methods (OECD 2002). These include: 

1) QSAR method – The approach used to normalize the NOEC data is clearly described (above). 

The approach is considered reliable because it’s application to LAS and other major surfactants is 

well documented in the scientific literature (Leo and Hansch 1979, Roberts 1991, van de Plassche et 

al. 1999). 

2) Clear input data – Reliable NOEC values from freshwater single-species chronic studies are 

used as described in Table 12A of the SIAR and listed above. 

3) Mode of action – LAS has a nonspecific mode of action described as “narcosis toxicity” 

(Roberts 1991). As expected from this mode of action, sensitivity of the tested species follows a 

log –normal and log-logistic distribution with a high degree of goodness of fit. The best fit of the 

data is to the log-logistic distribution. 

4) Minimum species requirements – Represented species include fish, crustaceans, insects, a 

rotifer, algae, and higher plants. 

5) Minimum sample size – The database consists of NOEC values on at least 12 freshwater species. 

6) Use of multiple data for same species – In the van de Plassche et al. (1999) review, the 

geometric mean value is used for species with multiple values (number of species indicated in Table 

12A). For the available data set, the geometric mean value of the valid studies is provided. 

7) Statistical fitting procedure – The specified Kolmogorov-Smirnov test was used as described 

above. Goodness of fit across distributions (i.e. log-normal versus log-logistic) was compared using 

the Cramer-von Mises statistical test as described by Versteeg et al. (1999). 

8) Estimation parameter – The reported value is as specified, the HC5 value with 50% confidence 

limits. 

9) Estimation of NOEC – The HC5 values support the conclusion of the mesocosm studies that no 

uncertainty (assessment) factor is needed to determine the NOEC value for LAS. The NOEC for 

LAS is derived from the entire database of freshwater chronic data, including the HC5 values and 

the mesocosm data, as discussed in the SIAR, section 4.1 Aquatic Effects. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 106

References 

Aldenberg, T., and Slob, W. 1993. Confidence limits for hazardous concentrations based on 

logistically distributed NOEC toxicity data. Ecotoxicol. Environ. Saf. 25:48-63. 

BKH. 1993. The use of existing data for estimation of the maximum tolerable environmental 

concentration of LAS. Part I: main report. Part II: data list, BKH, Delft (NL). 

Leo, A.J., and Hansch, C. 1979. Substituent Constants for Correlation Analysis in Chemistry and 

Biology. John Wiley & Sons, New York, NY (USA). 

Organization for Economic Cooperation and Development (OECD). 2002. Manual for Investigation 

of HPV Chemicals. Chapter 4: Initial Assessment for the Environment. Section 4.2. Guidance for the 

Initial Assessment of Aquatic Effects. October 2002. 

Roberts, D.W. 1991. QSAR issues in aquatic toxicity of surfactants. Sci. Total Environ. 109/110:557-

568. 

Schafer, R.E., and Sheffield, T.S. 1973. Inferences on the parameters of the logistic distribution. 

Biometrics 29:449-455. 

van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., Feijtel, T.C.J., and 

Belanger, S.E. 1999. Predicted no-effect concentrations and risk characterization of four surfactants: 

Linear alkylbenzene sulfonate, alcohol ethoxylates, alcohol ethoxylated sulfates, and soap. Environ. 

Toxicol. Chem. 18:2653-2663. 

Versteeg, D.J., Belanger, S.E., and Carr, G.J. 1999. Understanding single-species and model 

ecosystem sensitivity: Data-based comparison. Environ. Toxicol. Chem. 18:1329-1346. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 107

SIDS DOSSIER 

LINEAR ALKYLBENZENE 

SULFONATE (LAS) 

CAS NOs. 1322-98-1 

 25155-30-0 

 26248-24-8 

 27636-75-5 

 68081-81-2 

 68411-30-3 

 69669-44-9 

 85117-50-6 

 90194-45-9 

 127184-52-5 

Sponsor Country : United States of America 

Date: August 15, 2005 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 108

TABLE OF CONTENTS

1. GENERAL INFORMATION 

1.01 SUBSTANCE INFORMATION 

1.02 OECD INFORMATION 

1.03 CATEGORY JUSTIFICATION 

1.1 GENERAL SUBSTANCE INFORMATION 

1.2 SYNONYMS 

1.3 IMPURITIES 

1.4 ADDITIVES 

1.5 QUANTITY 

1.6 LABELLING AND CLASSIFICATION (USE AND/OR TRANSPORTATION) 

1.7 USE PATTERN 

1.8 OCCUPATIONAL EXPOSURE LIMIT VALUE 

1.9 SOURCES OF EXPOSURE 

1.10 ADDITIONAL REMARKS 

2. PHYSICAL-CHEMICAL DATA 

2.1 MELTING POINT 

2.2 BOILING POINT 

2.3 DENSITY (RELATIVE DENSITY) 

2.4 VAPOR PRESSURE 

2.5 PARTITION COEFFICIENT n-OCTANOL/WATER 

2.6 WATER SOLUBILITY 

2.7 FLASH POINT (LIQUIDS) 

2.8 AUTO FLAMMABILITY (SOLID/GASES) 

2.9 FLAMMABILITY 

2.10 EXPLOSIVE PROPERTIES 

2.11 OXIDISING PROPERTIES 

2.12 OXIDATION: REDUCTION POTENTIAL 

2.13 ADDITIONAL DATA 

3. ENVIRONMENTAL FATE AND PATHWAYS 

3.1 STABILITY 

3.1.1 PHOTODEGRADATION 

3.1.2 STABILITY IN WATER 

3.1.3 STABILITY IN SOIL 

3.2 MONITORING DATA (ENVIRONMENTAL) 

3.3 TRANSPORT AND DISTRIBUTION BETWEEN ENVIRONMENTAL COMPARTMENTS 

INCLUDING ESTIMATED ENVIRONMENTAL CONCENTRATIONS AND DISTRIBUTION 

PATHWAYS 

3.3.1 TRANSPORT 

3.3.2 THEORETICAL DISTRIBUTION (FUGACITY CALCULATION) 

3.4 MODE OF DEGRADATION IN ACTUAL USE 

3.5 BIODEGRADATION 

3.6 BOD-5, COD OR RATIO BOD-5/COD 

3.7 BIOACCUMULATION 

3.8 ADDITIONAL REMARKS 
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4. ECOTOXICITY 

4.1 ACUTE/PROLONGED TOXICITY TO FISH 

4.2 ACUTE TOXICITY TO AQUATIC INVERTEBRATES 

4.3 TOXICITY TO AQUATIC PLANTS e.g., ALGAE 

4.4 TOXICITY TO BACTERIA 

4.5 CHRONIC TOXICITY TO AQUATIC ORGANISMS 

4.5.1 CHRONIC TOXICITY TO FISH 

4.5.2 CHRONIC TOXICITY TO AQUATIC INVERTEBRATES 

 (e.g., DAPHNIA REPRODUCTION) 

4.6 TOXICITY TO TERRESTRIAL ORGANISMS 

4.6.1 TOXICITY TO SOIL DWELLING ORGANISMS 

4.6.2 TOXICITY TO TERRESTRIAL PLANTS 

4.6.3 TOXICITY TO OTHER NON-MAMMALIAN TERRESTRIAL SPECIES 

 (INCLUDING AVIAN) 

4.7 BIOLOGICAL EFFECTS MONITORING (INCLUDING BIOMAGNIFICATION 

4.8 BIOTRANSFORMATION AND KINETICS 

4.9 ADDITIONAL REMARKS 

5. TOXICITY 

5.1 ACUTE TOXICITY 

5.1.1 ACUTE ORAL TOXICITY 

5.1.2 ACUTE INHALATION TOXICITY 

5.1.3 ACUTE DERMAL TOXICITY 

5.1.4 ACUTE TOXICITY, OTHER ROUTES OF ADMINISTRATION 

5.2 CORROSIVENESS/IRRITATION 

5.2.1 SKIN IRRITATION/CORROSION 

5.2.2 EYE IRRITATION/CORROSION 

5.3 SKIN SENSITIZATION 

5.4 REPEATED DOSE TOXICITY 

5.5 GENETIC TOXICITY IN VITRO 

5.6 GENETIC TOXICITY IN VIVO 

5.7 CARCINOGENICITY 

5.8 TOXICITY TO REPRODUCTION 

5.9 DEVELOPMENTAL TOXICITY / TERATOGENICITY 

5.10 OTHER RELEVANT INFORMATION 

5.11 EXPERIENCE WITH HUMAN EXPOSURE 

REFERENCES 

APPENDIX A – BIBLIOGRAPHY 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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1. GENERAL INFORMATION

1.01 SUBSTANCE INFORMATION

A. CAS number The information provided in this dossier refers to various individual 

compounds and mixtures of sulfonated linear alkyl benzenes which are 

identified by the following CAS numbers and names: 

CAS No. EINECS No. Name 

1322-98-1 215-347-5 Decylbenzene sulfonic acid, sodium salt 

25155-30-0 246-680-4 Dodecylbenzene sulfonic acid, sodium salt 

26248-24-8 247-536-3 Tridecylbenzene sulfonic acid, sodium salt 

27636-75-5 248-583-2 Undecylbenzene sulfonic acid, sodium salt 

68081-81-2 268-356-1 C10-16 Monoalkylbenzene sulfonic acid, sodium salt 

68411-30-3 270-115-0 C10-13 Alkylbenzene sulfonic acid, sodium salt 

69669-44-9 274-070-8 C10-14 Alkyl derivatives benzene sulfonic acid, sodium salt 

85117-50-6 285-600-2 C10-14 Monoalkylbenzene sulfonic acid, sodium salt 

90194-45-9 290-656-6 C10-13 Alkyl derivatives benzene sulfonic acid, sodium salt 

127184-52-5 4-C10-13-sec Alkyl derivatives benzene sulfonic acid, sodium salt 

 B. Name (IUPAC name) See A. 

C. Name (OECD name) Linear alkylbenzene sulfonate (LAS) 

D. CAS Descriptor

Relatively consistent mixture of homologues with predominately linear 

(currently >95% for most products) varying alkyl chain lengths (from C10 to 

C14) and phenyl isomers with attachment of the para sulfonate (sodium salt) 

benzene ring to the alkyl chain at non-terminal positions. This description 

applies to all of the CAS numbers listed in 1.01A as shown by the alkyl 

chain distribution in the table in 1.01G. 

 E. EINECS-Number See A. 

 

 F. Molecular Formula See G. 

G. Structural Formula 

The linear alkyl carbon chain typically has 10 to 14 carbon units, with the approximate mole ratio varying 

somewhat regionally, as shown in the following table: 

CH3(CH2)

x

CH(CH2)

y

CH3

S03

 - Na+

where x+y=n and n=7-11

carbon units
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Region <C10 C10 C11 C12 C13 C14 >C14

Range of 

Averages 

Weighted 

Average* 

Canada 

68081-81-2 ≤1 <16 19-39 20-50 5-27 <3 <1 11.8 11.8 

Europe 

25155-30-0 

68081-81-2 

68411-30-3 

85117-50-6 

90194-45-9 

127184-52-5

≤1 8-20 19-39 20-50 5-27 <1-3 <1 11.6-11.8 11.7 

Japan 

68081-81-2 

68411-30-3 

69669-44-9

≤1 7-16 19-39 20-50 5-27 <1-3 <1 11.7-11.8 11.8 

United States 

1322-98-1** 

25155-30-0 

26248-24-8** 

27636-75-5** 

68081-81-2 

69669-44-9 

85117-50-6 

90194-45-9

<2 1-25 7-50 20-50 5-45 <1-10 <1 11.3-12.6 11.7 

*Weighted by production volume for each region. 

**Manufacture of LAS under these CAS numbers has recently been discontinued. 

The molecular weights depend on alkyl chain length and range from 338 (C11.3) to 356 (C12.6). As shown in the 

table, all the LAS category members (CAS numbers) have the alkyl chain distributions for the LAS category. 

All of the data in this assessment, except for homologue data identified as such, is on LAS category materials 

having the alkyl chain distribution shown in the table. The available information on the test substances is 

provided in the robust summary for each test. All results have been corrected for 100% activity. 

Commercial LAS is exclusively manufactured as mixtures of C10 to C13 or C14 alkyl chain homologues, 

having average alkyl chain lengths ranging from C11.3 to C12.6, with the predominant materials having average 

alkyl chain lengths ranging from C11.7 to C11.8 (Table above). Each alkyl chain homologue consists of a 

mixture of all the possible sulfophenyl isomers except for the 1-phenyl isomer which is not found in the 

commercial material. The catalyst used to make the LAB determines the distribution of the phenyl isomers 

in commercial LAS with the proportion of the 2-phenyl isomers ranging from 18 to 28% (Valtorta et al., 

2000). Consequently, commercial LAS consists of a mixture of 20 or more compounds, the 2-phenyl to 5-

phenyl isomers of the C10 homologue, the 2-phenyl to 6-phenyl isomers of the C11 and C12 homologues and 

the 2-phenyl to 7 phenyl isomers of the C13 homologue, etc. 

H. Substance Group Not applicable 

I. Substance Remark Not applicable 

J. Molecular Weight Range depending on alkyl chain length 

1.02 OECD INFORMATION

A. Sponsor Country: United States of America 

B. Lead Organization:

 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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 Name of Lead Organization: United States Environmental Protection Agency 

 Contact person: Mr. Oscar Hernandez 

 Address: 

 1200 Pennsylvania Avenue, N.W. 

 Washington, D.C. 20460 

 USA 

 Tel: (202) 564-7641 

 Email: hernandez.oscar@epa.gov 

C. Name of responder

 Name: John Heinze Ph.D., Consortium Manager 

 Address: 

Industry Coalition for the SIDS Assessment of LAS 

c/o Council for LAB/LAS Environmental Research 

 529 14th Street, N.W., Suite 807 

 Washington, D.C. 20045 

 USA 

 Tel: (202) 737-0171 

 Fax: (202) 737-8406 

 Consortium Participants 

 Center for LAB Environmental and Technical Studies for Asia (CLETSA) 

 Cognis Deutschland GmbH&Co.KG 

 Colgate-Palmolive Company 

 Huntsman Corporation 

 Kao Corporation 

 Lion Corporation 

 Petresa International N.V. 

 Quimica Venoco, CA 

 YPF SA 

 Sasol North America 

 Stepan Company 

 TAYCA Corporation 

 The Dial Corporation 

 The Procter & Gamble Company 

 Unilever Household and Personal Care North America 

 Additional Participants 

 Mitsubishi Chemical Corporation 

 Nippon Petrochemicals Co., Ltd. 

 W.R. Grace & Company 

1.03 CATEGORY JUSTIFICATION 

The LAS molecule contains an aromatic ring sulfonated at the para position and attached to a linear alkyl 

chain at any position except the terminal carbons. The alkyl carbon chain typically has 10 to 14 carbon 

atoms and the linearity of the alkyl chains ranges from 87 to 98%. While commercial LAS consists of more 

than 20 individual components, the ratio of the various homologues and isomers, representing different alkyl 

chain lengths and aromatic ring positions along the linear alkyl chain, is relatively constant in currently 

produced products, with the weighted average carbon number of the alkyl chain based on production volume 

per region between 11.7-11.8. LAS is supported as a category because of the close consistency of the 

mixtures, their commercial uses, fate, and health and environmental effects. LAS is the primary cleaning 

agent used in many laundry detergents and cleaners at concentrations up to 25 percent in consumer products, 

and up to 30 percent in commercial products, with the exception of one reported product at 45% percent in 

concentrated solid form that is mechanically dispensed into diluted solution for dishwashing. 
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1.1 GENERAL SUBSTANCE INFORMATION 

A. Type of Substance

 element [ ]; inorganic [ ]; natural substance [ ]; organic [X]; organometallic [ ]; 

 petroleum product [ ] 

B. Physical State (at 20°C and 1.013 hPa)

 gaseous [ ]; liquid [ ]; solid [X] for pure substance 

C. Purity 87-98% 

 Purity refers to the percent LAS, with iso-branched LAS and DATS 

considered to be impurities. The “activity” may also be stated, and 

represents the percent of active LAS in the solution (e.g., 50% active LAS is 

half strength LAS, the LAS of which will be 87-98% pure, with the 

remaining 50% consisting of water). 

D. Manufacturing Process

 LAS is manufactured from linear alkylbenzene (LAB) in self-contained, 

enclosed systems (see SIAR Annex, Format A, Section VI(1), for more 

information). LAB is produced by reacting paraffins with benzene and a 

catalyst and isolating the LAB by distillation. The LAB is then sulfonated, 

which in turn is then neutralized to sodium salts of LAS. 

1.2 SYNONYMS 

 Linear alkylbenzene sulfonates 

 LAS 

 Sodium-n-alkyl (C10-13) Benzene Sulfonate 

 Numerous trade names, e.g. Marlon A 

1.3 IMPURITIES 

 

 Remarks: Dialkyltetralin Sulfonates (DATS) and single methyl-branched alkyl chain 

LAS (iso-LAS) make up minor components in commercial LAS. 

Concentrations range from <1 to 8% for DATS and <1 to 6% for iso-LAS, 

depending on the manufacturing process used. Recent market information 

(LAS SIDS Consortium, unpublished, 2005) indicates that less than 5% of 

the global LAS production contains high levels of DATS. Consequently, the 

average (based on production volume) linearity and purity of LAS worldwide 

is greater than 95%. The presence of DATS and iso-LAS did not 

significantly affect the biodegradation of LAS relative to the pure linear 

component, as both DATS and iso-LAS are biodegradable substances. This 

is discussed in detail in the summaries at section 3.5(x) and 3.5(y). 

 References: 1) Nielsen, A.M., Britton, L.N., Beall, C.E., McCormick, T.P. and Russell, 

G.L. 1997. Biodegradation of coproducts of commercial linear alkylbenzene 

sulfonate. Environ. Sci. Technol. 31L3397-3404. 

 2) Cavalli, L., Cassani, G., Lazzarin, M., Maraschin, C., Nucci, G., and 

Valtorta, L. 1996b. Iso-branching of linear alkylbenzene sulphonate (LAS). 

Tenside Surf. Det. 33:393-398. 

 3) LAS SIDS Consortium, unpublished, 2005. 

 
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1.4 ADDITIVES

 

 Value: None 

 Remarks: No additives 

1.5 QUANTITY

 

 (a) 

 Remarks: Year 2000 data, as reported in a Colin A. Houston report, indicate an 

estimated volume of LAS consumption in North America (United States and 

Canada combined) as 390,000 metric tonnes. 

 Reference: Colin A. Houston. 2002. Surfactant Developments. Forecast to 2010. A 

Multiclient Study. Colin A. Houston & Associates, Inc., August 2002. 

 (b) 

 Remarks: In a market survey completed by ECOSOL in 2000, companies in Europe 

reported a total consumption of LAS of approximately 400,000 metric 

tonnes. This includes CAS numbers 1322-98-1, 25155-30-0, 68411-30-3, 

85117-50-6 and 90194-45-9. 

 Reference: HERA. 2004. HERA-LAS Human and Environmental Risk Assessment: 

Linear Alkylbenzene Sulphonates, LAS. CAS No. 68411-30-3, Version 2.0, 

May 2004; available at www.heraproject.com. 

 (c) 

 Remarks: Total LAS production for the companies surveyed in the most recent year for 

which data are available (generally 2002) was approximately 430,000 metric 

tonnes. Almost half of this production (198,000 metric tonnes) occurred in 

North America (United States and Canada combined). Production in Europe, 

as reported by the member companies surveyed, was approximately 152,000 

metric tonnes. Data cited above in (a) and (b) for LAS consumption in the 

United States and Europe are viewed as the more reliable estimates, because 

all LAS producers are not included in the coalition member survey. 

Production in Japan, where all the LAS producers are members of the 

consortium, was 85,000 metric tonnes and is considered a reliable estimate. 

 Reference: Industry Coalition for the SIDS Assessment of LAS Survey conducted in 

2002 (LAS SIDS Consortium Survey, 2002). 

 (d) 

 Remarks: More than 1 million tonnes per annum produced globally based on: (1) 364 

to 415 ktonnes produced annually in U.S. from 1987 to 199l; (2) 400 ktonne 

produced in Western Europe and 2570 ktonnes world-wide in 1995; (3) 950 

ktonnes produced in Europe, North America and Japan in 1994; (4) 2 million 

tonnes consumed world-wide in 1990; (5) 410 ktonne produced in Western 

Europe, 2.6 million tonnes worldwide in 1995. 

 Reference: (1) CHIMICA OGGI, Sept. 1998 

 (2) EU Risk Assessment Report for LAB, May 1997 

 (3) IPCS Environmental Health Criteria 169, WHO, 1996 

 (4) Nielsen et al. 1997 

 (5) Soap and Detergent Association, 1996 

1.6 LABELLING AND CLASSIFICATION

 Labelling
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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 Remarks: None designated 

 Classification

 Remarks: None designated 

1.7 USE PATTERN 

A. General

 Type of Use: Category:

 main Wide dispersive use 

 industrial Personal and domestic use 

 use Cleaning/Washing agent 

 Remarks: About 78-97% of the LAS consumption worldwide is in liquid and powder consumer 

and industrial laundry and fine fabric detergents. Another 2-10% of the LAS 

produced is used in consumer and industrial dishwashing liquids, with the remainder 

(1-5%) used in other consumer and industrial cleaners. 

B. Uses in Consumer Products 

 Function Amount present Physical state

 

 detergent up to 25% of formulation powder or liquid 

 Remarks: LAS is an anionic surfactant that lowers the surface tension of water, enabling soils 

and stains to loosen and release from fabrics and surfaces. LAS is the primary 

cleaning agent used in many liquid and powder laundry detergents and speciality 

household cleaners at concentrations up to 25 percent of the total formulation. 

The following table shows the percentage of LAS that occurs in various types of consumer detergent 

products. 

Consumer Product Range of Percent Composition that is LAS 

Type North America Europe Japan 

Laundry Detergents 

- Powders 

- Liquids 

- Tablets 

5-25% 

1-25% 

5-25% 

5-25% 

5-10% 

10-25% 

5-25% 

5-25% 

5-25% 

Liquid Fine Fabric 

Detergents - - 1-5% 

Bleaches - - 0.1-0.5% 

Pre-Washes - - 5-10% 

Fabric Conditioners 

(sheets) 0.1-0.5% - - 

Dishwashing Detergents 

(liquids) 5-25% 10-25% 1-5% 

General Cleaners 

(dilutable) 1-5% 1-5% - 

Hard Surface Cleaners 1-5% 0.1-0.5% 0.5-10% 

Other Cleaners - - 0.1-0.5% 

Face & Hand Soaps 

(bar) 1-5% - - 
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 Reference: 1) Soap and Detergent Association 1996 

 2) Survey data for Industry Coalition for the SIDS Assessment of LAS. 2002. 

C. Uses in Institutional and Industrial Products 

The following table shows the percentage of LAS that occurs in various types of institutional and industrial 

detergent products. 

Industrial Product Range of Percent Composition that is LAS 

Type North America Europe Japan 

Laundry Detergents 

- Powders 

- Liquids 

5-25% 

- 

5-10% 

10-25% 

5-10% 

- 

Pre-Washes - 10-25% - 

Dishwashing Detergents 

(liquids) 5-10% 25-30% 5-30% 

General Cleaners 

- Dilutable 

- Spray 

1-5% 

1-5% 

- 

- 

- 

- 

Hard Surface Cleaners - - 1-10% 

Disinfectants (liquids) 5-10% - - 

Other Uses 25-30%* 10-25% 10-25% 

6.1 * The only exception is a product containing 45% LAS that is a concentrated solid mechanically dispensed 

into diluted solution for dishwashing. 

Reference: 1) Soap and Detergent Association 1996 

 2) Survey data for Industry Coalition for the SIDS Assessment of LAS. 2002. 

1.8 OCCUPATIONAL EXPOSURE LIMIT VALUE

 Exposure limit value

 Type: None established by OSHA, ACGIH or NIOSH 

 Short term exposure limit value

 Value: None established by OSHA, ACGIH or NIOSH 

1.9 SOURCES OF EXPOSURE

 Remarks: Exposure to industrial workers is limited because this is an enclosed manufacturing 

process designed to minimize losses and the potential for release. Worker exposure is 

possible during the detergent formulation stage by inhalation of powders or dermal 

contact of powders and liquids. However, good manufacturing design practices (e.g. 

enclosed production, exhaust ventilation, dust collection) and personal protective 

equipment (e.g. protection clothing, eyewear, and glove) in place of at facilities that 

manufacture liquid and dry (granular/powder) materials sufficiently mitigate worker 

exposure to LAS. No special engineering controls or additional personal protective 

equipment are uniquely specified for LAS. 

 LAS is used primarily in household laundry and dishwashing cleaning products. 

After use, LAS is discharged into the wastewater treatment system. The exposure of 

the general human population and of environmental organisms depends on the 

application of LAS, the local sewage treatment practices, and on the characteristics of 

the receiving environment. 
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 It is reasonable to consider that the tasks with the greatest exposure to the consumer 

are hand dishwashing and hand washing of clothing. 

 Reference: 1) EU Risk Assessment Report for LAB, May 1997. 

 2) IPCS Environmental Health Criteria 169, WHO, 1996. 

1.10 ADDITIONAL REMARKS 

A. Options for disposal

 Remarks: Unused LAS may be recovered for reprocessing or disposed of by incineration or 

landfill or by flushing to sewage system; used material enters sewage system and is 

treated at WWTP. Spills may be recovered for reprocessing or disposal. 

 Reference: MSDS. 

B. Other remarks

 (a) 

 Remarks: The majority of LAS is disposed of in sewage during use as cleaning/washing agents. 

 Reference: Soap and Detergent Association 1996. 

 (b) 

Methods: A study conducted for the Soap and Detergent Association (Battelle 1999) 

measured the under 10 micron fraction delivered from 6 consumer product spray 

nozzles. The six standard trigger sprayers (TS800) were manufactured by Calmar 

Dispensing System, Inc. The specified average output of the sprayers, based on 

water at 90 strokes per minute, is no less than 0.75 mL per stroke. The specified 

spray pattern is a nearly circular pattern with a diameter of no less than four inches 

at a distance of approximately eight inches. The six trigger sprayers were evaluated 

to determine emitted aerosol size distribution, output per stroke and spray pattern in 

order to avoid choosing a trigger sprayer with abnormal characteristics for the 

experiment. Size distribution of aerosols generated from the six sprayers was 

measured using a laser diffraction particle sizer (Mastersizer Model X, Malvern 

Intruments Ltd). 

Remarks: The overall mean (n=30) is 0.11% particles under 10 microns and the standard 

deviation is 0.21. The very highest observation was 0.80% particles under 10 

microns. This testing only captured the spray particles that are under 600 microns, 

so the actual mean respirable particle percent of total volume sprayed is less than 

0.1%. The Battelle (1999) study also reported that for consumer spray products in 

normal use conditions, the peak breathing zone concentration under 10 microns 

ranged from 0.13-0.72 mg/m3

. HERA (2004) reported that measurements of 

aerosol particles under 6.4 microns in size generated upon spraying with typical 

surface cleaning spray products resulted in a product concentration of 0.35 mg/m3

. 

These estimates of exposure to respirable particles from consumer spray products 

indicate that inhalation is not a likely route of concern for human exposure (see 

SIAR Annex 1 for more information). Estimates of inhalation exposure apply to 

both consumer and commercial products as both use the same type of spray nozzles 

(for spray cleaners) and the same type of equipment to make powder/granulated 

products. The human experience with eye irritation covers both manufacturing and 

use of consumer and commercial products. 

References: 1) Battelle, Inc. 1999. Measurement and characterization of aerosols generate 

from a consumer spray product-pilot study. Final report to the Soap and Detergent 

Association. Battelle Study No. N003043A. January. 
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2) HERA. 2004. Linear Alkylbenzene Sulphonate, LAS. Human & Environmental 

Risk Assessment on ingredients of European household cleaning products. Version 

2.0, May 2004. http://www.heraproject.com/RiskAssessment.cfm

(c) 

Methods: A comprehensive testing program was undertaken to evaluate consumer exposure to 

dust from powdered enzyme detergent use in comparison with worker exposure at 

factories. Airborne dust was collected in consumers’ homes during normal use of 

laundry detergents. Consumer use of laundry products was then simulated in the 

laboratory to permit collection of sufficient samples for analysis of the amount of 

enzyme in detergent dust, and for detergent dust particle size distribution 

determinations and persistence measurements. Representative commercial products 

sold by Procter & Gamble were tested. Air sampling was carried out using an 

electrostatic precipitator using a battery powered source and was conducted 

continuously from the time each housewife began to pour laundry product for use 

until she left the laundry area. The entry orifice of the sampling device was located at 

a point spatially equivalent to the direction and distance from the housewife’s nose 

from the point of dust generation. Laboratory simulation of consumer practices was 

based on extensive consumer habits developed by a variety of conventional 

techniques. 

Remarks: The results of the in-home studies indicate that detergents contribute only 5% of the 

dust present during the time detergents are dispensed for laundering, with the rest of 

the dust believed to be mainly lint. Virtually all detergent dust (95%) settled in less 

than 2 minutes. On average, there is 0.27 μg detergent dust exposure per cup of 

product used for double-pour machine laundering. 

 Based on this amount, HERA (2004) calculated the amount of LAS exposure from 

laundry detergent use. Up to 22% (0.06 μg/use) of the detergent dust can be 

expected to be LAS. Assuming a worst case exposure (all dust is inhaled and 

laundry is done 3 times a day), the exposure to LAS of an average adult is estimated 

to be 0.003 μg/kg bw/day. This amount does not contribute significantly to the total 

exposure of LAS as compared to the amount from inhalation of aerosols from 

cleaning sprays, which is approximately 10-fold higher (0.04 μg/kg bw/day). 

References: 1) Hendricks, M.H. 1970. Measurement of enzyme laundry detergent product dust 

levels and characteristics in consumer use. J. Am. Oil Chem. Soc. 47:207-211. 

2) HERA. 2004. Linear Alkylbenzene Sulphonate, LAS. Human & Environmental 

Risk Assessment on ingredients of European household cleaning products. Version 

2.0, May 2004. http://www.heraproject.com/RiskAssessment.cfm
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2. PHYSICAL-CHEMICAL DATA

2.1 MELTING POINT

 

 (a) 

 Value: 198.5o

C 

 Decomposition: Onset at 444o

C (47% weight loss at 500oC) 

 Method: Thermal analysis was performed on the Netzsch DSC 204C and TG209C 

with N2 atmosphere. 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C10-14 Monoalkylbenzene sulfonic acid, sodium salt (CAS #85117-50-6); 

mean molecular weight = 348, average alkyl chain length = C12.0. The test 

material is a commercial product, contains 85% active matter and is a coarse, 

cream-colored powder at 25o

C. 

 Remarks: This measured melting point value is significantly lower than the EPI Suite 

estimated values for other LAS materials. Note that the activity represents 

the total percent active materials (LAS, iso-LAS and DATS) in the test 

substance. The nonactive material in a powdered sample of LAS is likely 

sodium sulfate and other salts which have very high melting points (e.g., 

sodium sulfate = 884°C) and would not interfere with the measurement of 

the LAS melting point. 

 Reference: Huntsman. 2002. Report of melting point analysis for NANSA HS 85/5. 

Cover memo from A. Ashworth to K.B. Sellstrom dated April 12, 2002. 

 Reliability: 2 Valid with restrictions

 (b) 

 Value: 274o

C 

 Decomposition: Not identified 

 Method: Estimation: EPI Suite (Mean or Weighted MP) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C10 LAS (CAS #1322-98-1) 

 Remarks: Structure modeled is the pure C10 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (c) 

 Value: 279o

C 

 Decomposition: Not identified 

 Method: Estimation: EPI Suite (Mean or Weighted MP) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C11 LAS (CAS #27636-75-5) 

 Remarks: Structure modeled is the pure C11 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (d) 

 Value: 284o

C 

 Decomposition: Not identified 

 Method: Estimation: EPI Suite (Mean or Weighted MP) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C12 LAS (CAS #25155-30-0) 

 Remarks: Structure modeled is the pure C12 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 
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 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (e) 

 Value: 290o

C 

 Decomposition: Not identified 

 Method: Estimation: EPI Suite (Mean or Weighted MP) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C13 LAS (CAS #26248-24-8) 

 Remarks: Structure modeled is the pure C13 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

2.2 BOILING POINT

 (a) 

 Decomposition: Onset at 444o

C (47% weight loss at 500oC) 

 Method: Thermal analysis was performed on the Netzsch DSC 204C and TG209C 

with N2 atmosphere. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test Substance: C10-14 monoalkylbenzene sulfonic acid, sodium salt (CAS #85117-50-6); 

mean molecular weight = 348, average alkyl chain length = C12.0. The test 

material is a commercial product, contains 85% active matter and is a coarse, 

cream-colored powder at 25o

C. 

 Remarks: Note that the activity represents the total percent active materials (LAS, isoLAS and DATS) in the test substance. The nonactive material in a powdered 

sample of LAS is likely sodium sulfate and other salts which have very high 

melting points (e.g., sodium sulfate = 884°C) and would not interfere with 

the measurement of the LAS melting point. 

 Reference: Huntsman. 2002. Report of melting point analysis for NANSA HS 85/5. 

Cover memo from A. Ashworth to K.B. Sellstrom dated April 12, 2002. 

 Reliability: 2 Valid with restrictions

 (b) 

 Value: 630o

C 

 Method: Estimation: EPI Suite (Adapted Stein & Brown method) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C10 LAS (CAS #1322-98-1) 

 Remarks: Structure modeled is the pure C10 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (c) 

 Value: 642o

C 

 Method: Estimation: EPI Suite (Adapted Stein & Brown method) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C11 LAS (CAS #27636-75-5) 

 Remarks: Structure modeled is the pure C11 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 
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 (d) 

 Value: 654o

C 

 Method: Estimation: EPI Suite (Adapted Stein & Brown method) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C12 LAS (CAS #25155-30-0) 

 Remarks: Structure modeled is the pure C12 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (e) 

 Value: 665oC 

 Method: Estimation: EPI Suite (Adapted Stein & Brown method) 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: C13 LAS (CAS #26248-24-8) 

 Remarks: Structure modeled is the pure C13 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

2.3 DENSITY

 (a) 

 Type: Bulk density [ ]; Density [ ]; Relative Density [X] 

 Value: 1.06 g/cm3

 Temperature: 20°C 

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6

 Remarks: Source cited in IUCLID is Sicherheitsdatenblatt “Marlon A 390; Huels Ag. 

vom 03.12.93 

 Reference: Cited in IUCLID Data Sheet for CAS #68411-30-3. 

 Reliability: 4 Not assignable. Original report not available for review. 

 (b) 

 Type: Bulk density [X]; Density [ ]; Relative Density [ ] 

 Value: 0.45 g/cm3

 (450 kg/m3) 

 Temperature: 20°C 

 GLP: Yes [ ] No [ ] ? [X] 

Test Substance: C10-14 monoalkylbenzene sulfonic acid, sodium salt (CAS #85117-50-6); 

mean molecular weight = 348, average alkyl chain length = C12.0. The test 

material is 85% active matter and is a coarse, cream-colored powder at 25o

C. 

 Reference: Huntsman 2002. Report on the melting point analysis for NANSA HS 85/S. 

Attached technical bulletin dated 04-01-1994. Cover memo from A. 

Ashworth to K.B. Sellstrom dated April 12, 2002. 

 Reliability: 4 Not assignable. Original report not available for review. 

 

 (c) 

 Type: Bulk density [X]; Density [ ]; Relative Density [ ]

 Value: ca. 550 kg/m3 

GLP: Yes [ ] No [X] ? [ ] 

Test Substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6

 Remarks: Source cited in IUCLID is Sicherheitsdatenblatt “Marlon A 390; Huels Ag. 

vom 03.12.93 
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 Reference: Cited in IUCLID Data Sheet for CAS #68411-30-3. 

Reliability: 4 Not assignable. Original report not available for review. 

2.4 VAPOR PRESSURE

 (a) 

 Value: 3 x 10-13 Pa 

 Method: Calculation 

 Test Substance: C12 LAS (CAS #25155-30-0) 

 Remarks: Cites estimates calculated by Lyman (see References). 

 Reference: 1) HERA. 2002. HERA-LAS Human and Environmental Risk Assessment: 

Linear Alkaylbenzene Sulphonates, LAS. CAS No. 68411-30-3, Draft #6, 

May 2002. 

 2) Lyman, W.J. 1985. Environmental exposure from chemicals, V.I, p.31, 

Neely, W.B., and Blau, G.E., editors. CRC Press. Boca Raton. 

 Reliability: 4 Not assignable. Original report not available for review. 

 (b) 

 Value: 2.88 x 10-12 Pa 

 Temperature: 25o C 

 Method: Estimation: EPI Suite (Modified Grain Method) 

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C10 LAS (CAS #1322-98-1) 

 Remarks: Structure modeled is the pure C10 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v.3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (c) 

 Value: 1.22 x 10-12 Pa 

 Temperature: 25o

C 

 Method: Estimation: EPI Suite (Modified Grain Method) 

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C11 LAS (CAS #27636-75-5) 

 Remarks: Structure modeled is the pure C11 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v.3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (d) 

 Value: 5.13 x 10-13 Pa 

 Temperature: 25o

C 

 Method: Estimation: EPI Suite (Modified Grain Method) 

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C12 LAS (CAS #25155-30-0) 

 Remarks: Structure modeled is the pure C12 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v.3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (e) 

 Value: 2.16 x 10-13 Pa 

 Temperature: 25o

C 

 Method: Estimation: EPI Suite (Modified Grain Method) 

 GLP: Yes [ ] No [X] ? [ ]
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 Test Substance: C13 LAS (CAS #26248-24-8) 

 Remarks: Structure modeled is the pure C13 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v.3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 

2.5 PARTITION COEFFICIENT log10Pow (log10Kow)

 (a) 

 Log Pow: 3.32 

 Method: Calculation

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C11.6 LAS 

 Remarks: Calculated for C11.6 LAS using the QSAR method of Leo and Hansch (1979) 

as modified by Roberts (1991) for surfactant structures. This takes into 

account the various phenyl positions along the linear alkyl chain. See the 

Roberts (1991) summary at 2.5(g) for a full description of the method 

modifications. 

 Reference: 1) HERA. 2002. HERA-LAS Human and Environmental Risk Assessment: 

Linear Alkylbenzene Sulphonates, LAS. CAS No. 68411-30-3, Draft #6, 

May 2002. 

 2) Leo, A.J. and Hansch, C. 1979. Substituent Constants for Correlation 

Analysis in Chemistry and Biology. J. Wiley & Sons, N.Y. 

 3) Roberts, D.W. 1991. QSAR issues in aquatic toxicity of surfactants. Sci. 

Total Environ. 109/110:557-568. 

 Reliability: 2 Valid with restrictions. These results are considered reliable because a 

standard calculation technique was employed. 

 (b) 

 Log Pow: 1.94 

 Method: Estimation: EPI Suite

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C10 Decylbezene sulfonic acid, sodium salt (CAS #1322-98-1) 

 Remarks: Structure modeled is the pure C10 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

(c) 

 Log Pow: 2.43 

 Method: Estimation: EPI Suite

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C11 LAS (CAS #27636-75-5) 

 Remarks: Structure modeled is the pure C11 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (d) 

 Log Pow: 2.92 

 Method: Estimation: EPI Suite

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C12 LAS (CAS #25155-30-0) 
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 Remarks: Structure modeled is the pure C12 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (e) 

 Log Pow: 3.42 

 Method: Estimation: EPI Suite

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C13 LAS (CAS #26248-24-8) 

 Remarks: Structure modeled is the pure C13 sodium salt homologue, 2-phenyl isomer, 

not the commercial material. 

 Reference: USEPA. 2000. EPI Suite v3.10. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software. 

 (f) 

 Remarks: In its review of LAS and related compounds, IPCS notes that while the 

octanol-water partition coefficient can be calculated in practice, it is 

impossible to measure Pow for surface-active compounds like LAS. This has 

been confirmed by Roberts (2000). 

 Reference: 1) IPCS. 1996. Environmental Health Criteria 169: Linear Alkylbenzene 

Sulfonates and Related Compounds. World Health Organization, Geneva, 

Switzerland. 

 2) Roberts, D.W. 2000. Use of octanol/water partition coefficient as 

hydrophobicity parameters in surfactant science. 5th World CESIO Congress 

2:1517-1524, May-June 2000, Firenze, Italy. 

 (g) 

 Methods: Acute lethal toxicity data for a range of anionic and non-ionic surfactants 

were analyzed with the objective of determining whether QSARs can be 

developed relating toxicity to calculated log P values. Approaches to dealing 

with the deficiencies in the Leo and Hansch (1979) fragment method for 

calculating log P of surfactants (related to mixtures and phenyl isomer 

position) were developed and applied to the general narcosis QSAR of 

Könemann (1981) as represented by Equation 1: 

 Log (1/LC50) = 0.87log P + 1.13 (EQ 1) 

 

 (for 14-d LC50 tests on guppies; n = 50, r = 0.998, s = 0.237) 

 Mixtures

 Two approaches were taken in this paper to address mixtures. In the first 

approach, P was calculated for each component individually then multiplied 

by the mole fraction and summed to give a weighted average log P. 

Alternatively, when only the overall average composition was known, log P 

was calculated for the average structure. 

 Phenyl isomer position 

 Since the fragment method gives values for log P that are independent of 

branch (i.e., phenyl isomer) position, a position-dependent branch factor 

(PDBF) was defined. Branching results in a decrease in the number of water 

molecules required to solvate the hydrocarbon chain by allowing water 

molecules to be shared between the two branches. Where both branches are 

long the water sharing effect should continue, although to a decreasing extent 

with increasing distance from the branching position, as long as the branches 

can be paired. To model this, a water sharing function log (CP + 1) was 
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defined in which CP is found by pairing off carbon atoms along the two 

branches up to the terminus of the shorter branch. Regression analysis 

correlating log (1/LC50) to goldfish with a combination of ALP [representing 

log P calculated without a branch factor] and log (CP + 1) [representing the 

water sharing function]: 

 Log (1/LC50) = 0.78ALP – 1.13 log (CP + 1) + 2.06 (EQ 2) 

 (for LC50 tests on guppies; n = 20, r = 0.997, s = 0.041) 

 Further, dividing the first two terms on the right of EQ 2 by 0.78 gave, 

assuming the role of the second term to be solely that of the branching factor, 

the following equation: 

 Log P = ALP – 1.44 log (CP + 1) (EQ 3) 

 Thus, the PDBF was defined as -1.44 log (CP + 1). Further details on this 

method are described in Roberts (1989). 

 Log P values calculated using EQ 3 were found to give good correlations 

with published river sediment sorption partition coefficients for LAS 

compounds, supporting the applicability and validity of the PDBF. Log P 

values calculated using EQ 3 were also used successfully in regression of 

toxicity data for pure LAS homologues and isomers to Daphnia magna and 

Gammarus pulex. The basic equation is similar to EQ 1 and has the general 

form: 

 Log (1/LC50) = alog P + b (EQ 4) 

 with the values for a, b and regression data shown in the following table: 

Daphnia

(H) 

Daphnia

(S) 

Gammarus

(H) 

Gammarus

(S) 

Value of a 0.7 0.64 0.76 0.71 

Value of b 2.23 2.44 2.46 2.27 

Regression 

data 

n 9 12 9 11 

r 0.987 0.955 0.966 0.950 

s 0.07 0.15 0.13 0.16 

F 263 103 98 83 

 Notes: H = hard water (250 mg/L CaCO3); S = soft water (25 mg/L CaCO3). Strongly 

negative outliers omitted. 

 The log P coefficients and intercepts for goldfish, Daphnia, and Gammarus

are all intermediate between those of Könemann’s QSAR equation (EQ 1), 

suggesting that a narcosis (possibly polar) mechanism applies to LAS acute 

toxicity. 

 Results: Agreement between observed and calculated toxicities for LAS is good. The 

fact that QSARs derived from compounds whose log P values are calculated 

with the PDBF give good predictions for unbranched compounds supports 

the validity of the PDBF for the type of branching encountered in LAS. 

 Remarks: The analyses presented in this paper indicates that the problems of 

calculating log P for surfactants can be overcome. The case for the 

applicability of the PDBF appears compelling, although it is based on 

indirect evidence. In terms of acute aquatic toxicity, anionic surfactants like 

LAS do not seem greatly different from unreactive non-surfactant organic 

chemicals. Anionic surfactants of various types have log (1/LC50) values 
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which are well predicted on the basis of their calculated log P values by 

QSAR equations resembling those associated with the polar narcosis 

mechanism. 

 Reference: 1) Roberts, D.W. 1991. QSAR issues in aquatic toxicity of surfactants. The 

Science of the Total Environment 10/110:557-568. 

 2) Roberts, D.W. 1989. Aquatic toxicity of linear alkyl benzene sulphonates 

(LAS) – A QSAR Approach. Communicaciones presentadas a las Jornada 

del Comite Espanol de la Detergencia 20:35-43. Also in J.E. Turner, M.W. 

England, T.W. Schulz and N. J. Kwaak (Eds) QSAR 88. Proc. Third Int. 

Workshop on Quantitative Structure-Activity Relationships in 

Environmental Toxicology 22-26 May 1988, Knoxville, TN, pp. 91-98. 

Available from NTIS. 

 3) Könemann, H. 1981. Quantitative structure-activity relationships in fish 

toxicity studies: Part I. Relationships for 50 industrial pollutants. Toxicology 

19:209-221. 

 4) Leo, A.J. and Hansch, C. 1979. Substituent Constants for Correlation 

Analysis in Chemistry and Biology, New York. 

 Reliability: 2 Valid with restrictions. Well documented QSAR analysis. 

2.6 WATER SOLUBILITY

A. Solubility

 (a) 

 Value: CMC = 0.1 g/L (C12 LAS) 

 Description: Miscible in water 

 Method: Surface tension of aqueous solutions of NaLAS was measured by an 

automated Lauda TE IC by the duNouy ring method. All solutions were 

prepared with water passed through a Nanopure water filter system and with 

sufficient salt to equalize the ionic strength. Solubility of commercial 

NaLAS was determined by slowly lowering the temperature in a Fisher 

Isotemp incubator over several days and recording the temperature at which 

the solutions first turned cloudy (cloud point). Clear points were determined 

by raising the temperature slowly over several days and recording when the 

solution cleared. The solubility of the C12 narrow-distribution phenyl isomers 

was determined by heating a saturated solution to 70°C for 0.5-3 h and then 

cooling to 5°C. After equilibrating to room temperature overnight, the 

cloudy mixture was centrifuged, and the clear supernatant drawn off, 

weighed, and dehydrated to determine percentage solids. The percentage 

dissolved was then calculated from the weight loss to the supernatant. 

 GLP: Yes [ ] No [ ] ? [?]

 Test Substance: C12 LAS and commercial C11-13 LAS (sodium salts) 

 Remarks: Surface activity increased with increasing average alkyl chain length. Some 

decrease in surface tension was observed with increasing phenyl isomer 

number, but the range of phenyl isomer distribution of commercial products 

is not large enough to significantly alter the surface tension vs. log 

concentration plot. Increasing the average alkyl chain length of LAS 

decreases solubility (i.e., increases cloud point). The following table shows 

the critical micelle concentration (CMC) for various chain lengths LAS 

tested. 

 

Chain length, isomer composition, dialkyltetralin 

sulfonate content 

CMC (g/L) 

C11 high 2-phenyl, low dialkyltetralinsulfonate 0.120 

C11 high 2-phenyl, high dialkyltetralinsulfonate 0.120 
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C11 low 2-phenyl, low dialkyltetralinsulfonate 0.120 

C12 low 2-phenyl, low dialkyltetralinsulfonate 0.105 

C13 low 2-phenyl, low dialkyltetralinsulfonate 0.038 

 Reference: Smith, D.L. 1997. Impact of composition on the performance of sodium 

linear alkylbenzenesulfonate (NaLAS). JAOCS 74:837-845. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Value: >250 g/L 

 Description: Miscible in water

 GLP: Yes [ ] No [ ] ? [?]

 Test Substance: Various LASs made from four commercial LABs, average alkyl chain length 

= 11.6 

 Remarks: The study shows that 25% solutions (250 g/L) of various LASs have cloud 

clear points (i.e., form clear solutions at rising temperatures) at temperatures 

of 2-21o

C, depending on LAS composition. Cloud and clear points decrease 

dramatically with increasing 2-phenyl isomer composition. The results 

demonstrate that 25% solutions of LAS are soluble at room temperature. 

 Reference: Cohen, L., Vergara, R., Moreno, A. and Berna, J.L. 1995. Influence of 2-

phenyl alkane and telralin content on solubility and viscosity of linear 

alkylbenzene sulfonate. JAOCS 72:115-122. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Value: ca. 250 g/L 

 Temperature: 20o

C 

 Description: Miscible in water 

 GLP: Yes [ ] No [X] ? [ ] 

Test Substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Miscible with water at 20o

C. Depending on the concentration, clear solutions 

(up to ~25% w/w) or inhomogeneous, viscous pastes were obtained. Sources 

cited are two reports by Huels AG dated 1988 and 1993. 

 Reference: Cited in IUCLID Data Sheet for CAS #68411-30-3. 

 Reliability: 4 Not assignable. Original report not available for review. 

 

B. pH Value, pKa Value

 (a) 

 pH Value: 10.0 ± 1.0 (1% solution) 

 GLP: Yes [ ] No [ ] ? [X]

 Remarks: C10-14 monoalkylbenzene sulfonic acid, sodium salt (CAS #85117-50-6); 

mean molecular weight = 348, average alkyl chain length = C12.0

 Reference: Huntsman 2002. Report on the melting point analysis for NANSA HS 85/S. 

Attached technical bulletin dated 04-01-1994. Cover memo from A. 

Ashworth to K.B. Sellstrom dated April 12, 2002. 

 Reliability: 4 Not assignable. Original report not available for review. 

 (b) 

 pKa Value: <1 for aromatic sulfonic acids such as benzosulfonic acid 

 Reference: Hodgman, C.D. 1961. Handbook of Chemistry and Physics, 43rd edition. The 

Chemical Rubber Publishing Company, Cleveland, Ohio. 

 Reliability: 4 Not assignable. Original data not available for review. 

2.7 FLASH POINT (liquids)
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 Remarks: Not applicable. 

2.8 AUTO FLAMMABILITY (solid/gases)

 Remarks: Not applicable. 

2.9 FLAMMABILITY

 Remarks: Not applicable. 

2.10 EXPLOSIVE PROPERTIES

 Remarks: Not applicable. 

2.11 OXIDISING PROPERTIES

 Remarks: Not applicable. 

2.12 OXIDATION: REDUCTION POTENTIAL

 Remarks: Not applicable. 

2.13 ADDITIONAL DATA

A. Henry’s law constant 

 Value: 6.37 x 10-3 Pa m3

/mole 

 Method: Estimation: EPI Suite 

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: LAS (CAS #25155-30-0) 

Remarks: Calculated using the bond method detailed in Meylan and Howard (1991) 

and the input parameters resident in the EPI Suite database. Assumes 25°C, 

molecular weight 348.48. Data reported in EPI Suite as 6.29 x 10-8 atmm3

/mole and converted to Pa m3/mole. 

 Reference: 1) USEPA. 2000. EPI Suite v3.10. 

 2) Meylan, W.M. and Howard, P.H. 1991. Bond contribution method for 

estimating Henry’s law constant. Environ. Toxicol. Chem. 10:1283-1293. 

 Reliability: 2 Valid with restrictions. Standard EPA estimation software.
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3. ENVIRONMENTAL FATE AND PATHWAYS

3.1 STABILITY

3.1.1 PHOTODEGRADATION

 

 (a) 

 Type: Air [ ]; Water [X]; Soil [ ]; Other [ ]

 Light source: Sunlight [ ]; Xenon lamp [ ]; Other [X] Mercury vapor lamp

 Light spectrum: 200-350 nm 

 Concentration: Initial LAS concentration 60 to 182 mg/1 

 Temperature: 28°C 

 Direct photolysis 

 Degradation: >95 % (weight/weight) after 20 minute (exposure time) 

 Indirect Photolysis 

 Degradation: Rapid photodegradation 

 Method: A series of photodegradation studies were conducted. Aqueous solution of 

LAS (pH 6.75) were passed through an irradiated tubular flow reactor. 

Reaction rates were obtained for both non-sensitized conditions and when 

ferric perchlorate (0.04 to 3.15 x 10-4 g-mole/L) was used as a sensitizer. A 

Hanovia 1200-watt mercury-vapor lamp was the source of radiation. The 

LAS concentration was determined by the methylene blue method. 

Appropriate controls were used. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS; activity: 95% (CAS #25155-30-0) 

 Remarks: Complete conversion of LAS to intermediates at an average residence time as 

low as 1 minute. The maximum conversion to CO2 was obtained at a 

residence time of 20 minutes and corresponded to 7 moles CO2 per mole of 

LAS. Reaction rate increases by two orders of magnitude in presence of 

ferric perchlorate. Half order kinetics with respect to light intensity and LAS 

concentration explained the data for nonsensitized conditions. An 

appropriate rate equation could be derived by assuming a second-order 

deactivation of light-activated LAS molecules. The sensitized reaction was 

believed to occur by abstraction of hydrogen atoms from LAS by hydroxyl 

radicals. Hydroxyl radicals presumably are produced by an electron-transfer 

reaction involving light-activated ferric ions. The mechanism is complex; 

over-all kinetics indicated a first-order effect of (Fe+3), 1.2 order in light 

intensity, and maxima in the rate for intermediate LAS and O2

concentrations. 

 Reference: Matsuura, T. and Smith, J.M. 1970. Kinetics of photodecomposition of 

dodecyl benzene sulfonate. Ing. Eng. Chem. Fund. 9:252-260. 

 Reliability: 2 Valid with restrictions

 (b) 

 Type: Air [ ]; Water [X]; Soil [ ]; Other [ ]

 Light source: Sunlight [ ]; Xenon lamp [X]; Other [ ] 

 Spectrum: >330 nm 

 Concentration: 50 mg/L 

 Temperature: 25°C; during photolysis the solution temperature reached 35-40o

C. 

 Indirect Photolysis: 

 Type of sensitizer: TiO2 suspension 

 Degradation: Rapid photodegradation of LAS (<1 to 2 hours) 

Method: A study was conducted to determine the photodegradation of LAS in aqueous 

TiO2 dispersions. Experiments were carried out with 25 mL solutions 

containing LAS surfactant with TiO2. Some experiments used open vessels 

(37 mL Pyrex glass reaction vessels) under aerobic conditions. Others used 
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vessels sealed with a rubber septum, the solution purged with argon and a 

fixed volume of oxygen injected. Spectrophotometric analysis was 

performed at regular intervals. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (CAS #25155-30-0) 

 Remarks: The reaction involves fast decomposition of the aromatic ring followed by 

slower oxidation of the aliphatic chain. 

 Reference: Hidaka, H., Kubata, H., Gratzel, M., Serpone, N. and Pelizzetti, E. 1985. 

Photodegradation of surfactants. I. Degradation of sodium dodecyl sulfonate 

in aqueous semiconductor dispersions. Nouveau J. Chemie 9:67-69. 

 Reliability: 2 Valid with restrictions

 

 (c) 

 Type: Air [ ]; Water [X]; Soil [ ]; Other [ ]

 Light source: Sunlight [ ]; Xenon lamp [ ]; Other [X] Mercury lamp

 Light spectrum: 400-580 nm 

 Spectrum: 223 nm 

 Concentration: 100 mg/L H20 

 Temperature: 20°C 

 Indirect Photolysis: 

 Type of sensitizer: Humic substances 

 Results: Photodegradation of LAS was reduced by humic substances by a factor of 2 

or more. The aliphatic side chains are degraded first, followed by aromatic 

ring cleavages. Degradation follows first order kinetics both with and 

without the presence of humics. 

 Method: The effects of humics on the photolytic degradation of LAS was studied. 

Soil humic substances were extracted by a cationic exchange resin/water 

suspension from a humic podzol. Water-soluble synthetic humic substances 

were prepared by autoxidation of pyrogallol in alkaline solution. Aqueous 

solutions of 15 mg/L humic substance and 100 mg/L LAS were irradiated 

with a mercury lamp. Photometric measurements were performed with a 

spectrophotometer for recording the changes caused by photolysis at definite 

times at 223 nm for LAS. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (CAS #25155-30-0) 

 Remarks: The presence of humic substances delays photodegradation of LAS, 

primarily because they act as UV-absorbers. The reaction between humics 

and LAS is dominated by electrostatic repulsion because of the negatively 

charged components at the given pH. The hydrophobic interaction between 

humics and LAS is relatively weak compared to the electrostatic repulsion. 

Possibly the sulfonic groups from LAS may be bound by metal bridges to 

humic surfaces. The study used humic substance with a relatively high 

proportion of aromatic carbon; whereas a lower proportion is more typical in 

natural environments. Therefore, the difference in photolysis rate is likely to 

be less pronounced. 

 Reference: Hermann, R., Gerke, J. and Ziechmann, W. 1997. Photodegradation of the 

surfactants LAS and dodecylpyridinium-chloride as affected by humic 

substances. Water, Air, and Soil Pollution 98:45-55. 

 Reliability: 2 Valid with restrictions 

3.1.2 STABILITY IN WATER

 Type: Abiotic (hydrolysis) [X] ; biotic (sediment)[ ]

 Results: LAS is stable in water. 

 GLP: Yes [ ] No [X] ? [ ]
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 Test substance: C10-13 alkylbenzene sulfonic acid, sodium salt (CAS #68411-30-3) 

 Remarks: LAS can be decomposed at extreme conditions such as elevated temperatures 

in the presence of inorganic acids such as phosphoric, sulphuric and 

hydrochloric acid, e.g.: 60-70% sulphuric acid at 140 - 190 degree C or with 

concentrated HCl in a sealed container at 150 - 200 degree C. Information as 

cited in IUCLID Data Sheet for CAS #68411-30-3 and in an analytical 

textbook. 

 Reference: Cross, J. and Dekker, M. (ed.). 1977. Anionic surfactants: Chemical 

analysis. Vol.8. Pp. 111-115. 

 Reliability: 4 Not assignable. Original studies not available for review. 

3.1.3 STABILITY IN SOIL

 (a) 

 Type: Laboratory 

 Radiolabel: Yes [X] No [ ] ? [ ]

 Concentration: 27.2 mg/kg (Ecosystem Section I) and 16.2 mg/kg (Ecosystem Section II) 

(initial amounts in dry soil); 0.44 mg/kg (I) and 0.19 (II) (at end of trials) 

 Temperature: Room temperature 

 Dissipation Time: DT50 = 13-26 days 

 Method: Soil cores taken from two ecosystems were collected and placed in a climate 

controlled “plant metabolism box”. Ecosystem Section I consisted of a 

heavy clay-like soil. Ecosystem Section II consisted of loose, sandy soil. 

Radiolabeled LAS (a defined mixture) absorbed to digested sludge was 

incorporated into the soils, after which the soils were planted with either 

grass, bush beans and radishes (Section I) or potatoes (Section II). The test 

systems were maintained under a defined standard climate (i.e., an average 

day in June in Northern Germany) for the vegetative period (76 and 106 

days, respectively for Sections I and II). At the end of the growing season 

samples were collected from plants and soil and subjected to radioanalysis. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: LAS. The authors state that they tested a defined mixture of LAS, but do not 

report the composition in this paper. 

 Remarks: Correponding to Ecosystem Sections I and II, 63.6% and 72.3% of initial 

radioactivity went to the atmosphere (primarily as CO2), 26.8% and 18.3% 

were detected in soil cores, 6.6% and 5.9% were present in biomass, and 

0.99% and 1.4% leached out with percolated water. The study shows that 

LAS adsorbed to digested sludge is relatively rapidly converted to CO2 and, 

to a lesser extent, polar organic secondary products in the upper soil layers. 

LAS and the secondary products are strongly adsorbed to the topsoil. LAS 

introduced into the topsoil by repeated application of sludge did not 

accumulate in the soil. Growth of crops is not impaired; the use of LAScontaining sludge had no adverse effect on the biomass yield (crop yield) 

under regulated use conditions. 

 Reference: Figge, K. and Schoberl, P. 1989. LAS and the application of sewage sludge 

in agriculture. Tenside Surf. Det. 26:122-128. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Type : Field trial [ ]; Laboratory [X]; Other [ ]

 Radiolabel: Yes [X] No [ ] ? [ ] 

 Concentration: 0.05 mg/kg 

 Soil temperature: Probably room temperature 

 Soil humidity: 80% of water holding capacity 

 Soil classification: DIN19863 [ ]; NF X31-107 [ ]; USDA [ ]; Other [X] mainly U.S. Soil 
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Conservation Service soil type designation, by Howard Laboratories, Dayton, 

Ohio 

 Organic Carbon: 1.4 - 50% 

 Soil pH: 4.9 - 8.4 

 Cation exchange 

 capacity: 0.15 meg/100 g soil dry weight 

 Microbial biomass: Activity in dpm/h/gdw soil varied from 11,327 to 51,683 

 Dissipation time: DT50 : 1.1 - 3.7 days 

 Method: other: described in reference 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C13 LAS (CAS #26248-24-8); activity 98% 

 Remarks: Half-lives ranged from 1.1 to 3.7 days (mineralization). First order 

dissipation rate constants ranged from 0.14 - 0.63/day. Mineralization 

occurred without a lag-period in every soil tested. Cycles of wetting and 

drying in the lab prior to testing resulted in more rapid and extensive 

mineralization. Community microbial activity did not correlate with rate or 

extent of mineralization. Microbial communities have indigenous ability to 

degrade low LAS concentrations, the ability is present in a wide array of soil 

types from various locations. 

 1. Soil Alpine, sand, pH 5.5, CEC 0.15, TOC 50 (mg/g) 

 2. Soil Bonnell, sandy loam, pH 8.4, CEC 29, TOC 31.6 

 3. Soil Brashear, silt loam, pH 7.7, CEC 37, TOC 24.9 

 4. Soil Eden, silt loam, pH 7.4, CEC 33, TOC 45.1 

 5. Soil Eden, loamy sand, pH 6.1, CEC 41, TOC 19.6 

 6. FL soil, sand, pH 4.9, CEC 6.3, TOC 13.8 

 7. GA soil, loamy sand, pH 4.9, CEC 15.5, TOC 1.4 

 8. Soil Huntington, loam, pH 7.3, CEC 24, TOC 20.1 

 9. Soil Lakin, loam, pH 6.5, CEC 24, TOC 34.6 

 10. Soil Pate, silt loam, pH 7.7, CEC 46, TOC 48.0. 

 Reference: Knaebel, D.B., Federle, T.W. and Vestal, J.R. 1990. Mineralisation of linear 

alkylbenzene sulfonate (LAS) and linear alcohol ethoxylate (LAE) in 11 

contrasting soils. Envir. Toxicol. Chem. 9:981-988. 

 Reliability: 2 Valid with restrictions 

(c) 

 Type : Field trial [X]; Laboratory [ ]; Other [ ]

 Radiolabel: Yes [ ] No [X] ? [ ] 

 Dissipation time: DT50 : 7 - 22 days 

 Results: In fields not recently spread with sludge, the concentrations of LAS found in 

the sludge amended soil were generally less than 1 mg/kg. This represents 

an estimated loss of LAS from soil of >98%. In fields recently spread, the 

concentrations in soil are in the range of <0.2 to 20 mg/kg, representing 

losses of LAS between 70 and 99% of the estimated total cumulative load. 

The authors conclude that overall the data indicate that an adequate safety 

margin exists between the concentrations of LAS in sludge-amended soils 

and those likely to affect the growth of crop plants. 

 Method: The disappearance of LAS from sludge-amended soils was investigated from 

51 fields on 24 farms in the Thames Water Authority, U.K. Annual sludge 

spreading averaged 6 ton/ha. Application of sludge was made by subsurface 

injection, surface spreading onto arable land with or without ploughing, or 

surface spreading onto pasture land. Regular sampling was conducted for up 

to 122 days. LAS concentrations in the soil were analyzed with HPLC. 

 GLP: Yes [ ] No [ ] ? [X]

Test substance: Commercial LAS as present in primary sludge or anaerobically digested 

sludge from WWTPs in the United Kingdom. 
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 Remarks: Half-lives compare well with those for ultimate degradation in lab soil tests 

(with ........14-C-evolution), indicating that the degradation of LAS does not 

 lead to the ... formation of significant levels of break-down intermediates in 

soil. 

 The homologue distribution of LAS in soil suggests that removal represents 

biodegradation rather than leaching. 

Reference: 1) Holt, M.S., Matthijs, E. and Waters, J. 1989. The concentrations and fate 

of linear alkylbenzene sulphonate in sludge amended soils. Wat. Res. 

23:749-759. 

 2) Waters, J., Holt, M.S., Matthijs, E. 1989. Fate of LAS in sludge amended 

 soils. Tenside Surfactants Detergents 26(2):129-135. 

 Reliability: 2 Valid with restrictions 

(d) 

 Type: Laboratory 

 Radiolabel: Yes [ ] No [X] ? [ ]

 Concentration: 8 to 488 mg/kg 

 Soil Composition: Coarse sand 67%, fine sand 16%, silt 8.6%, clay 6.2% and humus 2.7% 

 Organic Carbon: 1.5% 

 Method: LAS mixed with sewage sludge was applied to sandy agricultural soil and 

incubated for up to 8 weeks. Various microbial soil parameters were 

measured (see Section 4.4). LAS was quantified after methanol extraction 

using HPLC. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: C10-13 LAS obtained as an aqueous sodium salt solution with a LAS content 

of 16.1% (w/w), NA-LAS average molecular weight = 342 g/mol, 

distribution: C10 14%, C11 34%, C12 31%, and C13 21%. 

 Results: For nominal concentrations of 8 to 62 mg/kg, the depletion of LAS after 2 

weeks was more than 73%. At 488 mg/kg, only 15% depletion occurred. It 

is possible that this high LAS level may have inhibited microbial activity or 

caused a prolonged log phase to occur. 

 Reference: Elsgaard, L. Petersen, S.O. and Debosz, K. 2001b. Effects and risk 

assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects 

on soil microbiology as influenced by sewage sludge and incubation time. 

Environmental Toxicology and Chemistry. 20:1664-1672. 

 Reliability: 2 Valid with restrictions

(e) 

 Type : Field trial [X]; Laboratory [X]; Other [ ] 

 Radiolabel: Yes [ ] No [X] ? [ ] 

 Soil Content: Clay 1.8 - 4%, Silt 7.6 - 18.5 %, Sand 77.1 - 95.5% 

 Organic Carbon: Ranged from 0.9 - 1.79% 

 Soil pH: 5.2 – 6.8 

 Dissipation time: DT50: 3 days (lysimeters) 

 DT50: 7 days (field trials) 

 Method: Sewage sludge containing LAS was added to four cultivated sandy soils with 

low amounts of organic matter in field trials and lysimeter studies. The field 

trial lasted one year. For the lysimeter studies, undisturbed soil columns 

were taken from the corresponding field sites. 

 GLP: Yes [ ] No [ ] ? [X]

Test substance: Marlon A350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6; activity: 50% 

 Remarks: LAS are mobile in all four soils tested. They were detected down to a depth 

of 30-40 cm after being applied at the surface. After one week, a 

concentration of 500 mg/kg was measured in the 0-5 cm layer, which 

corresponds to 23% of the the total LAS. In the 5-10 cm layer, the 
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concentration was measured at 9.5 mg/kg (approximately 4%). Very little 

reached the 30-40 cm layer, although a value significantly above the limit of 

detection (0.050 mg/kg) was determined. No leaching was observed out of 

the soil columns and disappearance of LAS in the field trials was attributed to 

rapid biodegradation in the soil (approximately 99% of the total LAS was 

biodegraded after 42 days). The half-life was determined to be 3 days. There 

was a noticeable shift to shorter alkyl chain length homologues in the 

percolating water (i.e., longer alkyl chains were retained more strongly). 

These shorter chain length homologues have a lower toxicity. 

 Reference: Kuchler, T. and Schnaak, W. 1997. Behaviour of linear alkylbenzene 

sulfonates (LAS) in sandy soils with low amounts of organic matter. 

Chemosphere. 35:153-167. 

 Reliability: 2 Valid with restrictions 

 (f) 

 Type : Field trial [ ]; Laboratory [X]; Other [ ]

 Radiolabel: Yes [X] No [ ] ? [ ] 

 Concentration: 250 mg/kg 

 Soil temperature: 20°C 

 Soil humidity: 35 g water/100g soil dry weight 

 Soil pH: 6.9 - 7.1 

 Dissipation time: DT50 : 15.8 - 25.7 day 

 Method: Assays were conducted in flow-through microcosms with 15 g (dry wt) of 

soil adjusted to a 35% moisture level. The test substances were 14C ring 

labelled LAS pure homologues (C10, C11, C12, C13, C14) which were premixed 

with digester sludge and added to flasks at an initial concentration of 2.5, 25 

or 250 mg/kg. 14CO2 evolution was determined by LSC. The first-order 

biodegradation rate constant was estimated using non-linear regression 

techniques. The study was conducted in both sandy loam and loamy sand 

soil types. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: Pure LAS homologues C10-14 tested concurrently. 

 Results: The biodegradation rates followed first order kinetics over a wide range of 

concentrations and chain lengths. Half-lives (mineralization) were reported 

as C10 21 days; C11 25.7 d; C12 23.1 d; C13 18.2 d; C14 17.8 d 

 in sandy loam; C10 16.5 d and C14 15.8 d in loamy sand. The degradation rate 

constants were C10 0.033/d; C11 0.027/d, C12 0.030/d, C13 0.038/d, C14 0.039/d 

in sandy loam; C10 0.042/d C14 0.044/d in loamy sand Mineralisation 

efficiency averaged 65%. The remaining radiolabel was incorporated into 

microbial biomass or soil humic material. 

 Remarks: Half-lives for mineralization of the benzene ring, the rate-limiting step for 

LAS degradation, ranged from 18 to 26 days. 

 Reference: Ward, T.E. and Larson, R.J. 1989. Biodegradation kinetics of LAS in 

sludge-amended agricultural soils. Ecotox. and Environ. Safety 17:119-130. 

 Reliability: 2 Valid with restrictions

 (g) 

 Type: Field trial [ ]; Laboratory [ ]; Other [X] Greenhouse pot

 Radiolabel: Yes [ ] No [X] ? [ ] 

 Concentration: 3.7 to 5.1 g/kg dry wt 

 Soil composition: Clay 3.7 %, Silt 3.1 %, Fine Sand 19.5 %, Coarse Sand 71.4 % 

 Organic Carbon: 1.3% 

 Soil pH: 5.9 

 Cation exchange capacity: 10.7 cm/kg 

 Microbial biomass: not stated 
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 Method: Sewage sludge was incorporated into a sandy soil to give a range of very low 

to very high applications (0.4 to 90 mg/ha dry weight). LAS was added as 

water solutions to this mixture. The soil was transferred to pots and sown 

with barley, rape, or carrot and allowed to grow for 19, 85, and 30 days, 

respectively in a greenhouse. Plant-free controls were also established. 

Samples were collected of the soil and analyzed for total LAS and for 

individual homologues. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS C10-13, Approximate composition at start of study: C10 3%, C11 22%, C12

40%, C13 35% 

 Results: LAS was not taken up by plants and its degradation in soil increased by the 

presence of crop plants with concentration decreasing in rape from 27 

mg/kg (dry soil) to 0.7 - 1.4 mg/kg (dry soil) at harvesting after 30 days. 

During degradation, the relative fraction of homologues C10, C11, and C12

decreased, while C13 increased. 

 Reference: Mortensen, G.K., Elsgaard, H., Ambus, P., Jensen, E.S., and Gron, C. 2001. 

Influence of plant growth on degradation of linear alkylbenzene sulfonate in 

sludge-amended soil. J. Environ. Qual. 30:1266-1270. 

 Reliability: 2 Valid with restrictions

 (h) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] 

 Medium: Sludge modified soils 

 Method: LAS biodegradation and its kinetic parameters were studied in a land filling 

operation using sludges (15%) blended with soil (85%) at a site in Spain. 

Once the soil was blended with the sludges, grab samples were taken in three 

different zones of the plot. All samples were blended every day in order to 

have a daily composite sample. Immediately after sampling, all samples 

were frozen and then sieved to a 2 mm particle size. The sampling was 

conducted on 10 different days over a period of 62 days. LAS determination 

in sludge-modified soils was carried out by HPLC-UV. Degradation was 

determined based on LAS concentrations measured on the 10 sampling days. 

 Results: Average LAS concentrations on the 10 sampling days were 155, 55.6, 28.0, 

30.2, 35.2, 28.2, 31.6, 35.1, 19.3 and 16.7 for days 0, 6, 15, 20, 27, 34, 41, 48, 

55 and 62, respectively. The biodegradation level reached after 62 days was 

89.2%. Assuming first order kinetics, the half-life is 19.3 days. 

 Remarks: LAS adsorbed or precipitated on anaerobic sludges is biodegraded during soil 

amendment operations by commonly occurring micro organisms. The table 

shows a shift in the percent homologue distribution on days 0 and 62, 

demonstrating that higher molecular weight homologues exhibit stronger soil 

adsorption. 

% phenyl homologue Day 0 Day 62 

C10 3.7 1.2 

C11 29.4 18.7 

C12 41.4 48.9 

C13 25.5 31.2 

 Reference: de Ferrer, J., Moreno, A., Vaquero, M.T. and Comellas, L. 1997. 

Monitoring of LAS in direct discharge situations. Tenside Surf. Det. 34:278-

283. 

 Reliability: 2 Valid with restrictions 

 

3.2 MONITORING DATA (ENVIRONMENTAL) 
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(a) 

Type of Measurements: Background [ ]; At contaminated site [ ]; Other [X] Mississippi River 

Medium: Surface Water

Results: LAS was detected in 16% of the 323 mainstem samples collected during the 

upstream sampling cruises at concentrations ranging from 0.1 to 10.3 μg/L, 

and in 15% of the 39 tributary samples at concentrations ranging from 0.1 to 

2.8 μg/L. LAS was detected in 21% of the 38 mainstem composite samples 

collected during the downstream cruises at concentrations ranging from 0.1 

to 2.8 μg/L and was not detected in any of the 16 tributary composite 

samples. LAS was detected in 85% of the 34 samples collected from the 

Thebes time-series site at concentrations ranging from 0.4 to 28.2 μg/L. 

Remarks: The 2,800 km reach of the Mississippi River between Minneapolis and New 

Orleans was examined for the occurrence of LAS. River water was sampled 

in the summer and fall of 1991 and in the spring of 1992 during upstream and 

downstream sampling cruises. LAS was analyzed using solid-phase 

extraction and gas chromatography/mass spectrophotometry. The range of 

average chain length for all dissolved LAS was 10.2-12.0, with an average of 

11.1. The removal of the higher LAS homologues and external isomers 

indicates that sorption and biodegradation are the principle processes 

affecting dissolved LAS. 

Reference: Tabor, C.F. and Barber, L.B. 1996. Fate of linear alkylbenzene sulfonate in 

the Mississippi River. Environ. Sci. Technol. 30:161-171. 

Reliability: 2 Valid with restrictions

(b) 

Type of Measurements: Background [ ]; At contaminated site [ ]; Other [X] Mississippi 

Medium: Sediment 

Results: LAS was present on all bottom sediments (33 locations) at concentrations 

ranging from 0.01 to 20 mg/kg dry matter. It should be noted that all 

concentrations were <0.1 mg/kg with the exception of the one extremely high 

level of 20 mg/kg. The 20 mg/kg sample was found at Pig’s Eye Slough, the 

canal carrying the Minneapolis STP effluent to the the Mississippi River. All 

concentrations are dry weight. 

Remarks: The 2,800 km reach of the Mississippi River between Minneapolis and New 

Orleans was examined for the occurrence of LAS. Bottom sediment was 

sampled in the summer and fall of 1991 and in the spring of 1992. 

Composite samples were collected at 25 locations during the downstream leg 

of each cruise. These samples consisted of 5-7 individual sediment samples 

on each of 2-3 transects in each pool. In addition, grab samples were taken at 

8 other locations during the downstream cruise. LAS was analyzed using 

solid-phase extraction and gas chromotography/mass spectrophotometry. 

The average chain length for sorbed LAS ranged from 10.7 to 12.5, with an 

average of 11.5. Sorbed LAS appears to degrade slowly. 

Reference: Tabor, C.F. and Barber, L.B. 1996. Fate of linear alkylbenzene sulfonate in 

the Mississippi River. Environ. Sci. Technol. 30:161-171. 

Reliability: 2 Valid with restrictions 

(c) 

 Type of Measurements: Background [ ]; At contaminated site [ ]; Other [X] Rivers in USA

 Medium: Influents, effluents, and surface water 

 Results: Average LAS influent concentrations ranged from 4.2-5.7 mg/L among the 

various types of treatment plants. LAS removal rates averaged 99.3% for 

activated sludge (n = 15), 98.0-98.5% for lagoon/oxidation ditch (n = 14), 

96.2% for rotating biological contact (n = 9) and 77.4% for trickling filters (n 

= 12). Concentrations of LAS below the mixing zone of wastewater 

treatment plants were generally below 50 μg/L, even though the samples 
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were collected under low flow (i.e., low dilution) conditions. The mean 

surface water concentrations ranged from <10 to 330 μg/L, with mean values 

of 42 to 46 μg/L. The highest concentration was observed in a low (less than 

3-fold) dilution irrigation canal below a trickling filter plant. All other values 

were <180 μg/L, with more than 80% of the sites below 50 μg/L. 

 Remarks: Surface water samples were collected in rivers at 50 locations in 11 states 

below wastewater treatment plants. Alkyl chain lengths of LAS averaged 

12.0 carbon units in most environmental compartments, with the exception of 

sludge solids and river sediments, in which an enrichment of longer chain 

lengths was observed. Since several of the wastewater treatment plants 

included in this study have dilution factors less than 3, these values include 

worst case estimates. 

 Reference: McAvoy, D.C., Eckhoff, W.S. and Rapaport, R.A. 1993. Fate of linear 

alkylbenzene sulfonate in the environment. Environ. Toxicol. Chem. 12:977-

987. 

 Reliability: 2 Valid with restrictions 

 

 (d) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Rivers in U.S.A.

 Medium: sediment 

 Results: Below outfall of trickling filter treatment plant: 190 ± 95 mg/kg dry matter 

 < 5 miles downstream: 11.9 ± 9.5 mg/kg dry matter; 

 > 5 miles downstream: 5.3 ± 4.7 mg/kg dry matter 

 Remarks: Monitoring studies for LAS in river sediment in Rapid Creek, USA below 

the outfall of a trickling filter sewage treatment plant. Compiled by Procter 

& Gamble between 1973 and 1986. 

 Reference: Rapaport, R.A. and Eckhoff, W.S. 1990. Monitoring linear alkylbenzene 

sulfonate in the environment: 1973-1986. Environ. Toxicol. Chem. 9:1245-

1257. 

 Reliability: 2 Valid with restrictions 

(e) 

 Type of Measurement: Background [X]; At contaminated site [ ]; Other [X] 

 Medium: Sewage treatment influents & effluents; rivers and sediments. 

 Results: The removal from four activated sludge and five trickling filter wastewater 

treatment facilities averaged 99.5% & 82.9% for LAS and 99.1% and 97.3% 

for LAS intermediate, respectively, for the activated sludge and trickling 

filter facilities. 

 Remarks: LAS concentrations in receiving waters downstream of four activated sludge 

treatment plants ranged from 0.002 to 0.081 mg/L. LAS concentrations in 

receiving waters downstram of five trickling filter treatment plants ranged 

from 0.004 to 0.094 mg/L. Upstream LAS concentrations ranged from 

<0.001 to 0.110 mg/L and <0.001 to 0.005 mg/L for the activated sludge and 

trickling filter treatment plants, respectively. 

 Reference: Trehy, M.L., Gledhill, W.E., Mieure, J.P., Adamove, J.E., Nielsen, A.M., 

Perkins, H.O. and Eckhoff, W.S. 1996. Environmental monitoring for linear 

alkylbenzene sulfonates, dialkyltetralin sulfonates and their biodegradation 

intermediates. Environmental Toxicology and Chemistry 15:233-240. 

 Reliability: 2 Valid with restrictions 

(f) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] concentrations in 

sludge from waste water treatment plants

 Medium: sludge 

 Results: (A) Conc. In sludge 0.7 and 0.4 g LAS/kg of dry matter (data from 2 plants) 

 (B) Conc. In sludge 0.5 and 0.1 g LAS/kg of dry matter (data from 2 plants) 
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 (C) Conc. In sludge 30.2; 12.8; 11.4; 7.0 and 7.5 g LAS/kg of dry matter 

(from 5 plants) 

 Remarks: (A) Plants with aeration/settling system 

 (B) Plants with activated sludge & aerobic digestion of sludges system 

 (C) Plants with activated sludge & anaerobic digestion of sludges. 

 The concentrations in sludge correlate with water hardness. The higher the 

water hardness, the greater the amount of calcium-precipitated LAS in the 

sludge. For example, the water hardness that resulted in the 30.2 g/kg value 

was >500 mg/L as calcium carbonate. This level of hardness is very high and 

is 2-3 times higher than the more typical range of 200-300 mg/L as calcium 

carbonate. The amount of LAS physically removed to the sludge during 

primary settleing versus biodegradaded can be seen in the following table. 

 

Treatment Plant 

(all from category C) 

Physical 

Removal 

LAS 

Biodegradation 

Water Hardness 

(as mg/L CaCO3) 

Alicante 35% 68.2% >500 

Sevilla S.E. 30% 75.6% 220 

Sevilla N. 27% 87% 315 

La China (Madrid) 16% 91% <100 

Viveros (Madrid) 15% 91.2% <100 

 

 Reference: Berna, J.L., de Ferrer, J., Moreno, A., Prats, D., Ruiz Bevia, F. 1989. The 

fate of LAS in the environment. Tenside Surfactants Detergents 26(2):101-

107. 

 Reliability: 2 Valid with restrictions 

 (g) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] STP effluent in the 

UK

 Medium: Final effluent 

 Results: Final effluent concentration of LAS from four trickling filter STPs ranged 

from 40 to 430 μg/L (mean 80 to 300 μg/L). 

 Remarks: Removal from trickling filter STPs averaged 92.9% 

 Reference: Holt, M.S., Daniel, M., Buckland, H. and Fox, K.K. 2000. Monitoring 

studies in the UK designed for validation of the Geo-Referenced Exposure 

Assessment Tool for European Rivers (GREAT-ER), 5th World CESIO 

Congress. V.2:1358-1369, Firenze, Italy. 

 Reliability: 2 Valid with restrictions 

 (h) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Lambro River (Italy)

 Results: Mean background LAS concentration downstream from the STP was 28 

μg/L. 

 Remarks: A two year water quality monitoring program was conducted in the river 

Lambro (northern Italy) during the period March 1997 to May 1998. Prior to 

1998, 40% of the local waste water was discharged untreated directly into the 

river. The plants were undersized activated sludge plants. From April to 

September 1997, grab samples were collected approximately once a month 

from 19 stations along the main channel of the river, its two main tributaries, 

and at two STPs located within the monitoring area. From November 1997 

to May 1998, the sampling protocol was modified and grab samples were 

replaced by 24-hour composite samples (one sample shot every 20 minutes) 

collected using automatic samplers, twice a month at four sites downstream 

of the Merone plant, at the STP overflow, and occasionally one site upstream 

of Merone. Additional studies were also performed in conjunction with the 

overall monitoring program. 
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 Reference: Gandolfi, C., Facchi, A., Whelan, M.J., Cassarri, G., Tartari, G. and 

Marcomini, A. 2000. Validation of the GREAT-ER model in the River 

Lambro catchment. 5th World CESIO Congress. V.2:1370-1379. 

 Reliability: 2 Valid with restrictions 

 (i) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Tiber River

 Medium: Sewage treatment plant activated sludge and surface water 

 Results: The average LAS concentrations in the Roma Nord activated sludge sewage 

treatment plant were 4.6 mg/L (influent), 0.068 mg/L (effluent), and 6000 

mg/kg dry matter (final sludge), which correspond to an overall 98.5% LAS 

removal rate in the plant. In the receiving waters of the Tiber River LAS 

was 9.7 μg/L in the aqueous phase and 1.8 mg/kg dry matter in the sediment. 

Total daily LAS entering the treatment plant amount to 1150 kg. About 

1.5% (17 kg) leave the treatment plant through the final effluent and 234 kg 

(about 20% of the influent LAS) are removed by the digested sludge. 

 Remarks: Samples were collected over several days in June 1993. It is important to 

note that LAS environmental fingerprints in effluent and surface waters differ 

from the composition of the commercial material. The relative ratio of the 

various homologues detected in the aquatic environmental samples is as 

follows: C10:C11:C12:C13 = 45:30:23:2 with an average carbon number of 

10.8. That is due to the alkyl chain switch to shorter homologues in water as 

a consequence of both biodegradation in the water phase, which is faster for 

the higher homologues, and of adsorption into sediments, suspended solids, 

and the sludge, which is more pronounced for higher homologues. The LAS 

homologue distribution in sludge is approximately in the mole ratio 

C10:C11:C12:C13 = 7:24:39:30 with an average carbon number of 11.9, as a 

consequence of a preferential adsorption of higher homologues. 

 Reference: DiCorcia, A., Samperi, R., Belloni, A., Marcomini, A., Zanette, M., Lemr, K. 

and Cavalli, L. 1994. LAS pilot study at the “Roma-Nord” sewage treatment 

plant and in the Tiber river. La Rivista Italiana Delle Sostanze Grasse. 

LXXI:467-475. 

 Reliability: 2 Valid with restrictions

 (j) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Rivers in five 

European Countries

 Medium: Sewage treatment plant activated sludge, river surface water, sediment 

 Results: A very high average LAS total removal of 99.2% (98.5-99.9%) in sewage 

treatment was found. LAS concentrations in river water below activated 

sludge treatment plants in five European countries ranged from <2.1 to 47 

μg/L. 

 Method: As part of a pilot study, LAS monitoring was conducted at five activated 

sludge sewage treatment plants located in Germany, the UK, the Netherlands, 

Spain and Italy. Samples were collected over 7-day monitoring periods. 

Daily flow-related composites of raw sewage and treated effluent were taken. 

On at least one day, samples were taken at 2 or 3 hour intervals to assess 

diurnal variations in LAS concentration. Sludge samples were also taken. 

Samples of river water and sediment were also collected from sites above and 

below the sewage effluent outfalls. Samples consisted of either grab or 

composite samples, as well as interval sampling to determine diurnal changes 

in LAS concentration. Sediment samples were collected from the top layer 

(0-5 cm) of the river bed in four of 5 pilot study locations. LAS 

determinations were made with validated trace enrichment-HPLC procedures 

employing a specific fluorescence detector. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 140

 Remarks: LAS concentrations in raw sewage ranged from 4.0 to 15.1 mg/L. Only low 

concentrations of LAS were discharged to the receiving waters. The range of 

mean effluent concentrations was 0.009-0.140 mg/L. The mean 

concentration of LAS in river sediments below effluent discharges ranged 

from 0.49-5.3 μg/g. Below treatment plants, LAS levels in sediments were 

very similar (and sometimes lower) than levels above treatment plants. 

Based on these observations, the authors suggest that LAS is bioeliminated in 

river sediments. LAS levels in digested sludge from Spain and Italy ranged 

from 6.0 to 9.4 g/kg dry weight. Differences in the main operating 

characteristics at the five sites (e.g., treatment type, plant size, sludge 

retention time, hydraulic retention time, temperature) were not found to 

greatly influence the removal of LAS. 

 Reference: Waters, J. and Feijtel, T.C.J. 1995. AIS/CESIO Environmental Surfactant 

monitoring programme: Outcome of five national pilot studies on linear 

alkylbenzene sulphonate (LAS). Chemosphere 30:1939-1956. 

 Reliability: 2 Valid with restrictions 

 (k) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Red Beck, a small 

Yorkshire stream

 Medium: Sewage treatment effluents 

 Results: The results show an LAS concentration, corrected for dilution, of 0.07 

mg/L (uncorrected 0.033 mg/L) at Sunny Bank (the furthest downstream 

station, approximately 4.8 km from the out fall) after 6 hours of travel time. 

The calculated half-life was in the 2-3 h range, indicating kinetics faster 

than that of laboratory biodegradation studies in river waters. 

 Method: LAS and water quality parameters have been measured at seven sites 

downstream of the effluent discharge point of a trickling filter treatment plant 

(Shibden Head Sewage Treatment Works, Yorkshire, UK). This study was 

carried out specifically to measure in-stream removal kinetics of LAS. 

Time of travel was measured by detection of a fluorescent dye (Rhodamine 

WT) added to the effluent. Increase in flow as the river proceeds through 

the catchment was determined by flow measurements and boron dilution 

rate. Nine sampling stations were selected. The study began with the 

injection of Rhodamine WT dye to the final effluent. The concentration 

profile of the dye pulse was established from plots of fluorescence intensity 

versus time, which allowed the measurement of LAS concentration in the 

same stream volumes of water as the flow moved downstream. LAS 

concentrations were corrected for increased flow of the stream (and dilution 

of LAS) by inputs from side streams. Water samples were collected using 

automatic samples (time proportional or time proportional centroid 

composites) and/or grab samples and analyzed for water quality parameters 

and LAS. Boron was used as a reference substance for measuring the 

increasing stream flow as boron is highly soluble in water and nondegradable. LAS was analyzed as per the method of Holt et al. 1995. 

Briefly, LAS was extracted from the samples by solid phase extraction on 

C18 cartridges, eluted with methanol, evaporated under nitrogen to dryness, 

reconstituted in 1 mL methanol, and analyzed by reverse phase HPLC on a 

C18 column with fluorescence detection. 

 Remarks: The study indicates that an LAS removal half-life of 2-3 hours will be 

appropriate for small shallow streams, which have an LAS concentration 

between 50-250 μg/L, for use in the GREAT-ER model calibration 

exercise. 

 Reference: Fox, K., Holt, M., Daniel, M., Buckland, H., and Guymer, I. 2000. Removal 

of linear alkylbenzene sulfonate from a small Yorkshire stream. Contribution 

to GREAT-ER project #7. Sci. Total Environ. 251:265-275. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 141

 Reliability: 2 Valid with restrictions 

 

 (l) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Dutch surface water

 Medium: Surface water downstream of activated sludge STP outfalls just after the 

mixing zone. 

 Results: The mean LAS concentration in surface waters just downstream of the 

mixing zone was 14.2 μg/L, with a range mostly between <2 to 47 μg/L. 

 Remarks: Mean derived from a total of 23 records taken from the joint NVZ/VROM 

monitoring program of sewage treatment plants around the Netherlands. 

Samples were collected during three consecutive days from seven different 

sewage treatment plants. 

 Reference: 1) Feijtel, T.C.J. and van de Plassche, E.J. 1995. Environmental Risk 

Characterization of 4 Major Surfactants used in the Netherlands. RIVM 

Report No. 679101 025. 

 2) Matthijs, E., Holt, M.S., Kiewist, A.. and Rijs, G.B. 1999. Environmental 

monitoring for LAS, AE, AES, AS, and soap. Environ. Toxicol. Chem. 

18:2634-2644. 

 Reliability: 2 Valid with restrictions 

 (m) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Rivers in Japan 

Medium: Surface water 

 Results: Measured LAS concentrations from March 1998 to September 2002 ranged 

from below the detection limit (< 4 μg/L) to 81μg/L. The 95th percentile 

values ranged from below detection (< 4 μg/L) to 48.7 μg/L. The following 

table shows the maximum, median and 95th percentile LAS concentrations 

along with the number of samples in which LAS was detected. 

 

LAS Concentration (μg/L) 

Site # 

# 

Data 

Points Maximum Median 95th Percentile 

1 18 7.0 <4.0 7.0 

2 2 12.0 8.0 11.6 

3 18 24.0 9.5 16.4 

4 18 50.0 6.0 44.1 

5 18 81.0 9.5 48.7 

6 2 <4.0 <4.0 <4.0 

7 14 17.0 5.0 13.8 

All Sites 90 81.0 6.0 33.1 

 Methods: River water samples were collected from seven sites on four urban rivers in 

Japan (Tamagawa, Edogawa, Arakawa, and Yodogawa Rivers), as 

summarized in the following table. 

 

Site 

# 

River 

Name Site Name 

Water 

Area 

Categ

ory 

Description 

BOD in 1999 

Median/75th%

ile 

(mg/L) 

1 Tamagawa Hamura-seki A Upstream. Drinking water intake site. 0.5/0.5 

2 Tamagawa Harabashi B 

Midstream. Just below municipal 

wastewater treatment plant effluent 

discharge 

2.1/2.3 

3 Tamagawa Denen-chofu-seki B Midstream 1.6/1.7 

4 Edogawa Kanamachi A Downstream. Drinking water intake site 1.4/1.7 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 142

5 Arakawa Chisui-bashi B Midstream 4.6/5.5 

6 Arakawa Sasame-bashi C 

Downstream. Just below municipal 

wastewater treatment plant effluent 

discharge 

2.5/3.1 

7 Yodogawa Hirakata-oohashi B Midstream. Drinking water intake site 1.6/1.9 

 Grab samples were collected four times a year (summer, autumn, winter, and 

spring) at each sampling location. River water was characterized at each 

sampling occasion for BOD, TOC, SS, pH, Cl, NH4 and MBAS. LAS was 

complexed with MBAS, extracted, passed through a cation-exchange 

column, and the concentration of C10-13 LAS measured using HPLC. 

Populations in the catchments of the four rivers are relatively dense and 

municipal wastewater treatment coverage rates are middle to high (i.e., from 

60-70% to over 90% coverage). The seven sites cover upstream (Site 1), 

midstream (2, 3, 5, 7), and downstream (4, 6), and water area categories 

ranging from A to C. Two of the sites (2, 6) are just below municipal 

wastewater treatment plant effluent discharges. Three sites (1, 4, 7) are near 

drinking water intake sites. 

 Reference: Nishiyama, N., Yamamoto, A., and Takei, T. 2003. 37th Annual meeting of 

the Japan Society of Water Environment, Kumamoto, Japan. 

 Japan Soap and Detergent Association (JSDA). Annual reports of 

environmental issues (Years 1999, 2000, 2001, 2002). 

 Reliability: 2 Valid with restrictions 

 (n) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Europe STP sludge

 Medium: Anaerobic sludge 

 Results: Typical values are between 3.4 and 9.4 g/kg dry matter, with a mean of 5.6 

g/kg. 

 Remarks: Mean based on a total of 16 records. The LAS homologue distribution in 

sludge is approximately in the mole ratio C10:C11:C12:C13 = 7:24:39:30, with 

an average carbon number of 11.9, as a consequence of a preferential 

adsorption of higher homologues. The possible differences of LAS 

concentration is wet sludge, freshly produced at a STP from that of dry 

sludge, aged and dried before its use in agriculture, should be taken into 

account. It was found (Carlsen et al. 2002) that the LAS concentration in the 

bulk dry sludge could drop up to 74% compared to that of the wet sludge. 

Carlsen et al. (2002) also found that the average LAS concentration in soil 

core samples taken in a cultivated field spread with medium amounts of 

sludge was 1.12 mg/kg in the 0-10 cm depth. Lower LAS concentrations 

were recorded at depths from 10-50 cm. 

 Reference: 1) Carlsen, L., Metzon, M.B. and Kjelsmark, J. 2002. Linear alkylbenzene 

sulfonates (LAS) in the terrestrial environment. The Science of the Total 

Environment. 290:225-230. 

 2) Feijtel, T.C.J., Matthijs, E., Rottiers, A., Rijs, G.B.J., Kiewiet, A. and de 

Nijs, A. 1995. AIS/CESIO environmental surfactant monitoring program. 

Part 1: LAS monitoring study in “de Meer” STP and receiving river 

“Leidsche Rijn”. Chemosphere. 30:1053-1066. 

 3) Holt, M.S., Water, J., Comber, M.H.I., Armitage, R., Morris, G. and 

Nebery, C. 1995. AIS/CESIO environmental surfactant monitoring 

programme. SDIA sewage treatment pilot study on LAS. Wat. Res. 

29:2063-2070. 

 4) Sanchez Leal, J., Garcia, M.T., Tomas, R., de Ferrer, J. and Bengoechea, 

C. 1994. Linear alkylbenzene sulfonate removal. Tenside Surf. Det. 

31:253-256. 

 Reliability: 2 Valid with restrictions 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 143

(o) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] concentrations in 

sludge-amended agricultural soils

 Medium: soil 

 Method: An extensive monitoring study was performed on sludge-amended soils in 

the Thames Water Authority area, UK, by a Soap and Detergent Industry 

Association task force. A total of 51 fields from 24 farms were used, with 

sites representing a range of soil types, frequency and level of sludge 

applications, and agricultural uses. A total of 35 of the fields were pasture 

lands and 16 fields were arable land. The majority of fields were surface 

spread with primary and anaerobically digested sludge containing 

approximately 4.5% dry solids. 

 Results: Forty two farm sites that had received their most recent sludge application 

prior to 1987 (the study year) were monitored to establish the levels of LAS 

in sludge amended soils. Thirty five (83%) of the samples contained LAS 

levels below 1 mg/kg soil (mean = 0.7 mg/kg). The seven other sites 

contained LAS levels between 1.1 and 2.5 mg/kg soil. Nine sites received 

sludge applications in January to May 1987. Sampling was conducted in 

May 1987 and resulted in LAS concentrations ranging from <0.2 to 19.8 

mg/kg. The highest LAS concentrations in soil (19.8, 10.6, 7.8, and 4.5 

mg/kg) were recorded within days after the sludge application. 

 Remarks: Soil concentrations dropped significantly in less than two months (e.g., the 

19.8 mg/kg value dropped to 2.1 mg/kg in 55 days). The average chain 

length of the LAS found in soil samples was C11.7. 

 Reference: Waters, J., Holt, M.S., Matthijs, E. 1989. Fate of LAS in sludge amended 

soils. Tenside Surfactants Detergents 26(2):129-135. 

 Reliability: 2 Valid with restrictions 

(p) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] concentrations in 

sludge-amended agricultural soils

 Medium: sludge and soil 

 Method: This paper collects the literature on the concentrations of LAS in sludgeamended soil resulting from the use of sewage sludge applications on 

agricultrual fields. Data were compiled from a variety of original reference 

sources. 

 Results: The concentrations of LAS in sludge are shown in the following table: 

Sludge Description Concentration (mg/kg dw) Reference * 

Anaerobic 2,900 - 11,900 McEvoy and Giger 1985 

Anaerobic 4,660 - 1,540 Rapaport et al. 1987 

Aerobic 182 - 432 Matthijs and De Henau 1987 

Anaerobic 1,330 - 9,930 Matthijs and De Henau 1987 

Anaerobic 5,500 Marcomini 1988 

Aerobic 100 - 500 Berna et al. 1989 

Anaerobic 7,000 - 30,200 Berna et al. 1989 

Aerobic 152 ± 120 McAvoy et al. 1993 

Anaerobic 10,460 ± 5,170 McAvoy et al. 1993 

Anaerobic 11,500 - 14,000 Cavalli et al. 1993 

Anaerobic 12,100 - 17,800 Prats et al. 1993 

Anaerobic 6,000 ± 1,200 Di Corcia et al. 1994 

Primary 3,400 - 5,930 Feijtel et al. 1995 

Aerobic 205 Feijtel et al. 1995 

Aerobic 11 - <500 VKI 1997 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 144

Anaerobic 1,000 - 16,100 VKI 1997 

* See article for full citations. 

The concentrations of LAS in sludge-amended soil are shown in the 

following table. 

Initial Concentration 

(mg/kg dw) 

Typical Concentration * 

(mg/kg dw) Reference** 

16, 27 -- Figge et al. 1989 

45 5 Marcomini et al. 1989 

16,53 0.3 Berna et al. 1989 

Max. 66 0-20 Waters et al. 1989 

Max. 145 0-8 Holt et al. 1992 

Max. 250 1-7 Ward et al. 1989 

22.4 0.7, 3.1 Prats et al. 1993 

* Typical values after a test period 

** See article for full citations 

 Remarks: The range of LAS concentrations in sludge rarely exceeds 30,000 mg/kg dw. 

The range of LAS concentrations in sludge-amended soil also is low. 

 Reference: Cavalli, L., and Valtorta, L. Surfactants in sludge-amended soil. Tenside 

Surfactants Detergents 36:22-28. 

 Reliability: 2 Valid with restrictions 

 (q) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Coastal waters and 

harbor sediments with municipal and industrial discharge

 Medium: marine sediments 

 Test Substance: The chemical standard was a commercial LAS with a low 

dialkyltetralinsulfonates content (<0.5%) in a single standard mixture with 

proportional composition of the homologues C10 3.9%, C11 37.4%, C12 35.4% 

and C13 23.1% (Petroquimica Espanola S.A.) 

 Method: Sediment samples were taken from 23 sites along the Mediterranean coast of 

Spain and from three sites on the Atlantic coast. Water samples were taken 

at 14 sites on the Mediterranean coast. Samples underwent standard sample 

preparation and were analyzed using HPLC/MS. Samples were analyzed for 

individual LAS homologues (C10, C11, C12, C13) and other nonionic 

surfactants and their degradation products. 

 Results: In seawater the concentrations of LAS across all the samples ranged from 2.4 

to 92 μg/L and in marine sediment the concentrations of total LAS ranged 

from 0.1 to 238 mg/kg dry weight. Concentrations were higher in the 

sediments than in the water column, with the highest concentrations found in 

sediments collected in the proximity to the outflow of untreated urban 

wastewaters. The average carbon chain length of LAS ranged from 10.6 to 

11.6 in water and 12.0 to 12.8 in sediment. 

 Remarks: High concentrations of nonionic surfactants and their degradation products 

have been shown to accumulate in sediments, which seem to act as a sink for 

LAS in studied areas. The relative concentrations of the lower homologues 

C10 and C11 LAS in water samples are higher than the typical laundry 

detergent, mainly due to the partial removal and/or enrichment of these 

species during transportation of the wastewater in the sewage system because 

of the higher degradation and adsorption tendency of the longer alkyl chain 

homologues. The longer chain lengths are preferentially sorbed to particulate 

matter because of their high lipophilicity, thus explaining the increase in 

relative concentration of C12 and C13 homologues in the sediment samples. 

When interpreting this study, it is important to note that hot spots such as 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 145

described are not representative of European coastal sediments. Little or no 

macrofauna lives in such sediment, probably due to multistressor pressure. 

 Reference: Petrovic, M., Fernandez-Alba, A.R., Borrull, F., Marce, R.M., Mazo, E.G., 

and Barcelo, D. 2002. Occurrence and distribution of nonionic surfactants, 

their degradation products, and linear alkylbenzene sulfonates in coastal 

waters and sediments in Spain. Environmental Toxicology and Chemistry 

21:37-46. 

 Reliability: 2 Valid with restrictions 

 (r) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Coastal sediments in 

Bay of Cadiz, Spain 

Medium: Estuarine and marine sediments 

 Method: Sediment samples were collected from seven stations (5 in the Bay of Cadiz, 

2 in the Barbate River), representing a range of low, moderate, and high 

levels of chemical contamination. Samples were collected using a 0.025m2

Van Veen grab sampler during winter and summer in the same year. LAS 

was measured using specific HPLC analytical techniques. Fourteen heavy 

metal contaminants were also measured. Concurrent sediment toxicity tests 

were also conducted in which the rate of burial for clams (Ruditipes 

philippinarum) was measured over 48 hours and the survival of amphipods 

(Microdeutopus gryllotalpa) was measured over 10 days of exposure to 

whole sediments. 

 Results: LAS concentrations in the sediment ranged from 1.2-26.7 mg/kg dw in the 

summer and 1.2-62.1 mg/kg dw in the winter. Five of the 7 stations had LAS 

concentrations < 2.6 mg/kg dw. 

 Remarks: No mortality was observed in the clam toxicity studies. Clam burial was 

fastest in the uncontaminated sites (e.g., ET50 = 0.01-0.76 hours in winter), 

intermediate in moderately polluted sites (e.g., ET50 = 0.92-1.29 hours in 

winter), and slowest in highly polluted sites (e.g., ET50 > 48 hours in 

winter).The highest survival in the amphipod studies was in the 

uncontaminated site (85% survival) and the lowest survival was in the highly 

polluted site (16% survival). LAS is the only organic component of 

untreated sewage discharges considered, and sediment contaminants also 

included high levels of Ag and Pb. 

 Reference: DelValls, T.A., Forja, J.M. and Gomez-Parra, A. 2002. Seasonality of 

contamination, toxicity, and quality values in sediments from littoral 

ecosystems in the Gulf of Cadiz (SW Spain). Chemosphere. 46:1033-1043. 

 Reliability: 2 Valid with restrictions 

 (s) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other[X]; Coastal sediments in 

Denmark

 Medium: marine sediments 

 Method: Two core samples of 1 meter length were taken in the Baltic Sea, one in the 

inner Stockholm archipelago, and one north of Gotland, in the autumn of 

2000. Sediment samples were also taken from five locations in Haderslev 

Fiord on December 20, 2000. On April 3, 2001, samples were taken from 

five locations each in Vejle and Kolding Fiords. All samples were analyzed 

for total alkylbenzene sulfonates (LAS), and if possible, branched (branched 

dodecylbenzene sulfonates (BDS)) and linear alkylbenzene sulfonates 

separately. In addition, soap and volatile solids were analyzed separately. 

 Results: Danish marine sediments are not generally contaminated with LAS. The 

levels of health sediments are near or below detection limits. The 

concentration of LAS in soft sediments of the Baltic Sea along the Swedish 

coast is <0.5-1 mg/kg dry wt. Soap can be detected in high concentrations 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 146

(1,000-2,000 mg/kg dry wt.) in sediments, where LAS could not be detected 

(<0.05 mg/kg dry wt.). Sediments from a Danish shipping port (Haderslev 

Fiord), as previously reported by Danish EPA, were found to contain 

relatively high concentrations of LAS (2-20 mg/kg dry wt.) as well as 

extremely high soap concentrations (3,000-10,000 mg/kg dry wt.) and many 

other pollutants. 

 Remarks: The authors conclude that the environmental problem in Haderslev Fiord is 

not LAS or soap, but the fact that the whole sediment consists of stinking 

sludge formed by past discharges of untreated sewage and today’s overflow 

of sewage from emergency spillways in the municipal sewage system. The 

presence of BDS in the sediments demonstrates that this a historical problem. 

 Reference: Folke, J., Cassani, G., de Ferrer, J., Lopez, I., Karlsson, M.O., and 

Willumsen, B. 2003. Linear alkylbenzene sulphonates, branched 

dodecylbenzene sulfonates and soap analyzed in marine sediments from the 

Baltic proper and Little Belt. Tenside Surf. Det. 40:17-24. 

 Reliability: 2 Valid with restrictions 

 (t) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Coastal sediments 

receiving untreated urban effluents

 Medium: marine sediments 

 Test Substance: LAS C10-14 (sum of all homologues) 

 Method: There were three objectives to the study: 1) determine LAS levels in coastal 

sediments in areas receiving discharges of untreated urban effluents; 2) 

determine LAS distribution between the solid phase and the interstitial water; 

and 3) determine the presence of SPCs in the sediment column at depths 

below the aerobic oxidation/reduction interface. The study was carried out in 

a salt marsh in the south part of the Bay of Cadiz in the southwest of Spain. 

Samples were taken at three stations in an area where LAS levels are very 

high due to untreated urban effluents. Ten cores of sediment were collected 

at each station, frozen, cut into 1 cm thick sections and analyzed using 

standard HPLC/FL preparation, analysis, and cleanup techniques. Analyses 

were conducted to determine both LAS concentrations and concentrations of 

long-chain sulfophenyl carboxylic acids (SPCs) resulting from LAS 

biodegradation. 

 Results: The vertical profile of LAS concentrations in the sediment and interstitial 

waters showed a sharp reduction with depth, whereas the long chain SPCs (6-

13 carbon atoms) was greatest at 10-14 cm depth where the interstitial water 

becomes anoxic. Surface (0-8 cm) sediment concentrations (dry weight) for 

total LAS and SPCs are shown below. 

 

Station Location Total LAS 

(mg/kg) 

Total SPCs 

(μg/kg) 

B Close to discharge 

point 138.6 924.6 

C Distant, strong 

tidal current 16.4 224.2 

A Distant, weaker 

tidal current 0.8 70.6 

 The partition coefficients between the solid phase of the sediment versus the 

interstitial water are very different for LAS and for its degradation 

intermediates. For LAS, the organic carbon-based partition coefficient 

values were between 2.4 x 103 and 6.6 x 105

 L/kg for the homologues C10 and 

C13, respectively. For the longer chain SPCs, the partition coefficients are 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 147

several orders of magnitude lower as a consequence as their lower 

hydrophobicity. 

 Remarks: The LAS concentration in the upper sediment layer (0-8 cm) decreased with 

distance from the point of effluent discharge. The concentration of LAS in 

the sediment was up to 1000 times greater than that in the interstitial water. 

For SPC, the concentrations in the sediment and interstitial water were 

similar to each other. 

 Reference: Leon, V.M., Gonzalez-Mazo, E., Pajares, J.M.F., and Gomez-Parra, A. 2001. 

Vertical distribution profiles of linear alkylbenzene sulfonates and their longchain intermediate degradation products in coastal marine sediments. 

Environmental Toxicology and Chemistry 20:2171-2178. 

 Reliability: 2 Valid with restrictions 

 (u) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Predicted marine 

water concentrations in the North Sea

 Medium: Estuarine and marine surface water 

 Method: LAS environmental concentrations were predicted from per capita LAS use 

(2.5 g LAS/cap/day in Western Europe), water treatment statistics, and 

population estimates for Western Europe. 

 Results: The predicted LAS concentration range in the estuaries around the North Sea 

are 0.9-9 μg/L, which is in agreement with field monitoring data (1-9 μg/L) 

from the western Scheldt estuary. 

 Remarks: A risk assessment of LAS in marine sediments was initiated in 2002 and is 

expected to be available in 2004. 

 Reference: Temara, A., Carr, G., Webb, S., Versteeg, D. and Feijtel, T. 2001. Marine 

risk assessment: linear alkylbenzene sulfonate (LAS) in the North Sea. 

Marine Poll. Bulletin. 42:635-642. 

 Reliability: 2 Valid with restrictions 

 (v) 

 Type of Measurement: Background [ ]; At contaminated site [ ]; Other [X] Coastal waters and 

sediments in the Elbe estuary

 Medium: Surface water and marine sediments 

 Test Substance: LAS 

 Method: Water samples (100-L) were collected from a depth of 5 m at several 

locations in the Elbe estuary of the German Bight of the North Sea. 

Sediment samples were collected at the same locations. All samples were 

extracted and analyzed for LAS and other compounds (e.g. nonylphenols) 

present in detergents. 

 Results: The maximum concentration of LAS in surface waters was 0.03 μg/L and 

occurred in marinas in the Elbe estuary. Sediment LAS concentration ranged 

from 39-109 μg/kg dry weight. 

 Remarks: The LAS found in marina sediment probably originated from the discharges 

of municipal wastewater treatment plants. 

 Reference: Bester, K., Theobald, N., and Schroeder, H.Fr. 2001. Nonylphenols, 

nonylphenol-ethoxylates, linear alkylbenzenesulfonates (LAS) and bis (4-

schlorophenyl)–sulfone in the German Bight of the North Sea. 

Chemosphere. 45:817-826. 

 Reliability: 2 Valid with restrictions 
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UNEP PUBLICATIONS 148

3.3 TRANSPORT AND DISTRIBUTION BETWEEN ENVIRONMENTAL 

 COMPARTMENTS INCLUDING ESTIMATED ENVIRONMENTAL 

 CONCENTRATIONS AND DISTRIBUTION PATHWAYS 

3.3.1 TRANSPORT 

 

 (a) 

 Type: partition coefficient 

 Media: sludge 

 Method: Monitoring data were collected in a pilot-scale municipal activated sludge 

treatment plant. The plant consisted of a completely mixed aeration tank 

(490L) and a secondary settler (280L). The plant was operated at C12 LAS 

influent concentrations between 2 and 12 mg/L and at sludge retention times 

of 10 and 27 days. At least every other day 24-h samples of 2.5L influent 

and 2.5L effluent were collected in PE bottles and total (sum of adsorbed and 

dissolved) LAS concentrations were determined using an HPLC method 

adapted from Feijtel et al. 1995. At least once a day 200 mL grab samples 

were taken from the aeration tank and return sludge and transferred into PE 

centrifuge tubes for determination of dissolved and absorbed LAS. The 

sludge samples were immediately centrifuged for 15 min at 3500 rpm. The 

supernatant was transferred into PE bottles and preserved by 3% formalin 

and stored for a maximum of 10 days at 4°C until further analysis. 

Representative aliquots of pre-settled influent, final effluent, or supernatant 

of the centrifuged sludge samples were passed over 6 mL preconditioned C18 

SPE columns at a rate not exceeding 10 mL/min. The SPE columns were 

washed with 2 mL methanol/water and eluted with 5 mL of methanol. The 

eluate was then passed through strong anion exchange (SAX) columns, 

washed, eluted and subsequently evaporated to dryness under a gentle flow 

of nitrogen gas. The dry residue was dissolved in 2-5 mL of HPLC mobile 

phase. The HPLC was operated according to specifications. Identification of 

the different LAS alkyl homologues and quantification were made against a 

commercial LAS mixture (Marlon A390). A sorption-isotherm and the 

kinetics of adsorption and desorption of LAS to activated sludge were 

determined in batch experiments. Three different biodegradation tests were 

also carried out (an OECD 301F ready biodegradation test; a batch activated 

sludge [BAS] test; and a “by-pass” test developed to mimic condition of the 

pilot scale activated sludge plant). Only the sorption results are presented 

here. 

 Results: Kp (C12 LAS): 3210 L/kg (log Kp = 3.5) 

 Kp (commercial C11.6 LAS mixture): 2,500 L/kg (log Kp = 3.4) 

Test Substance: C12 LAS 

 Remarks: Sorption equilibrium was achieved rapidly, within 5-10 minutes. Desorption 

was less pronounced, but still reached rapid equilibration. The sludge-water 

partition coefficient Kp of 3210 L/kg volatile suspended solids is reported. 

Applying the same QSAR for the commercial C11.6 LAS mixture results in a 

value of log Kp = 3.4 (i.e., Kp = 2500 L/kg), consistent with Feijtel et al. 1999 

(see section 3.3.1(b)). In the other experiments conducted in this study, only 

2-8% was present as dissolved C12 LAS, with the remaining 92-98% 

adsorbed to the sludge. Despite this high degree of sorption, more than 99% 

of the LAS load was removed by biodegradation, showing that the adsorbed 

fraction as well as the soluble fraction of LAS is readily available for 

biodegradation. 

 Reference: Temmink, H. and Klapwijk, B. 2004. Fate of LAS in activated sludge plants. 

Water Research 38:903-912. 

 Reliability: 2 Valid with restrictions
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 149

 (b) 

 Type: partition coefficient 

 Media: sludge 

 Method: QSAR analysis 

 Results: Kp (C11 LAS): 1000 L/kg (log Kp = 3.0) 

 Kp (C12 LAS): 3162 L/kg (log Kp = 3.5) 

 Kp (commercial C11.6 LAS mixture): 2,512 L/kg 

Test Substance: Pure C11 and C12 LAS; and commercial C11.6 LAS 

 Remarks: The Kp values for C11 and C12 LAS are reported in this study as 

experimentally determined by Games et al. (1982), although they actually 

appear to be as reported in Games (1982; see 3.3.1 (d) for summary). The Kp

for the commercial C11.6 LAS mixture is calculated by Feijtel et al. using the 

reported C11 and C12 values. Also cites as a model input the log Koc from 

Traina et al. 1995 (see 3.3.1(b) for summary). These values are consistent 

with the experimental results of Temmink and Kapwijk (see 3.3.1(a). 

 Reference: Feijtel, T.C.J., Struijs, J., and Matthijs, E. 1999. Exposure modelling of 

detergent surfactants – Prediction of 90th-percentile concentrations in The 

Netherlands. Environ. Toxicol. Chem. 18:2645-2652. 

 Reliability: 4 Not assignable (see 3.3.1(e) for Games 1982) 

 (c) 

 Type: organic carbon partition coefficient 

 Media: dissolved humic substances 

 Method: The association of C10, C12 and C14 LAS with natural and specimen-grade 

dissolved humic substances (DHS) was measured with fluorescence 

quenching and with ultracentrifugation techniques. Water-soluble organic 

carbon (Carlisle-WSOC) was obtained and extracted from 0-0.1 m depth of a 

Carlisle muck in northwest Ohio. The acid-soluble fraction (Carlisle-HA) 

was suspended, centrifuged, and dialyzed to remove Cl-

 and to reduce the 

polyvalent cation content. The specimen-grade humic acid was purchased 

from Aldrich Chemical Company (Aldrich-HA). Suwanee River humic acid 

(SRHA) was obtained from the International Humic Substances Society. The 

fluorescence quenching followed the method of Guathier et al. (1986). 

Aliquots of the humic acid were placed in borosilicate bottles containing 

either NaCl, CaCl2, or concentrated synthetic river water, capped and 

incubated at 25°C for 18-24 hours, after which an aliquot of C10, C12 or C14

LAS was added and the solutions equilibrated at 25°C for 2 hours. All 

treatments were prepared in triplicate. After 2 hours, 3 mL of each sample 

solution was placed into cuvettes and the fluorescence of LAS measured with 

a Perkin Elmer LS 5B spectrofluorometer. Ultraviolet absorption 

measurements were made at 230 and 288 nm with a Beckman DU 6 UV-vis 

spectrophotometer. For the second independent analytical method, a batch 

ultracentrifugation method was developed. Aliquots of C12 LAS were added 

to polyallomer utltracentrifuge tubes containing the humic acid in a 

background electrolyte of either NaCl or CaCl2 and allowed to equilibrate at 

25°C. All treatments were prepared in triplicate. After 2 hours, the samples 

were centrifuged at 141,000 g for 6 hours at 25°C. The supernatants were 

decanted and saved for analysis. The walls of the centrifuge tubes were 

extracted with CH3OH, which was saved for analysis. The concentration of 

C12 LAS in the supernatants and in the CH3OH extracts was determined by 

exciting the solutions in cuvettes at 230 nm and the emission intensity 

recorded at 288 nm with a Perkin Elmer LS-5B spectrofluorometer. The 

quantity of C12 LAS associated with DHS was calculated from the difference 

in the initial and final solution concentrations, following the correction for 

the quantity of C12 LAS sorbed to the walls of the centrifuge tubes. 
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 Results: The average Log Koc values over the four DHS materials (Aldrich-HA, 

Carlisle-WSOC, Carlisle-HA, and SRHA) for each LAS chain length tested 

are: 

 Log Koc (C10 LAS): 4.02 L/kg 

 Log Koc (C12 LAS): 4.83 L/kg 

 Log Koc (C14 LAS): 5.49 L/kg 

 The data for Ca-saturated Aldrich-HA was linear over the entire 

concentration range of DHS, whereas some curvatura was present in the data 

from the Ca-saturated SRHA, and considerable deviation from linearity was 

apparent in many of the Na-saturated DHS solutions. 

Test Substance: C10 LAS (98% purity), C12 LAS (93% purity), and C14 LAS (88% purity), 

each synthesized at Procter and Gamble. Uniformly 14C-ring labeled C10-, 

C12- and C14-LAS were obtained from New England Nuclear and were 93.8, 

96.3 and 92.5% pure, with specific activities of 26.6, 68.2, and 34.3 μCi/mg, 

respectively. 

 Remarks: Good agreement was obtained with both of the analytical methods, indicating 

that both techniques can be used to quantify the effects of DHS on speciation 

of LAS in natural waters with certain limitations. LAS-DHS partition 

coefficients increased with increasing length of the alkyl chain in the LAS. 

These data indicate the significance of nonpolar forces in LAS-organic 

matter interactions. Good agreement was found between the partition 

coefficients obtained from the two analytical techniques and those calculated 

from the response of uptake and depuration studies conducted with fathead 

minnows. 

 Reference: Traina, S.J., McAvoy, D.C. and Versteeg, D.J. 1996. Association of LAS 

with dissolved humic substances and its effect on bioavailability. Env. Sci. 

Technol. 30:1300-1309. 

 Reliability: 2 Valid with restrictions 

 (d) 

 Type: Adsorption [X]; Desorption [ ]; Volatility [ ]; Other [ ]

 Media: water - activated sludge 

 Method: estimation of Kd with Freundlich equation 

 Results: The Kd of commercial LAS was between 660 and 5200 L/kg (6 citations), 

dependant on organic carbon content and other characteristics of the solid 

phase. 

Remarks: Concentration in liquid phase between 1 and 80 mg/L. 

 Reference: Painter, H.A. and Zabel, T.F. 1988. Review of the environmental safety of 

LAS. Wrc Medmendham, UK. Report No. CO 1659-M/1/EV 8658. 

 Reliability: 4 Not assignable 

 

(e) 

 Type: Adsorption [X]; Desorption [ ]; Volatility [ ]; Other [ ]

 Media: water - activated sludge and water - river sediment 

 Method: Comparison of Kd for LAS C10 to C14 - Year 1982 

 Results: Adsorption coefficients (L/kg) in activated sludge and river sediment, 

respectively, for LAS homologues: 

 C10: 220 and 41 

 C11: 1000 and 100 

 C12: 3070 and 330 

 C13: 9330 and 990 

 C14: 2950 (for river sediment – not determined for activated sludge) 

Remarks: Kd is highly dependent on the alkyl chain length of LAS with approximately 

a factor of 3 increase per carbon and on the position of the phenyl group on 

the alkyl chain. The organic carbon content is also an important factor, 

varying by a factor of 10 between activated sludge and river sediment. 
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UNEP PUBLICATIONS 151

 Reference: 1) Games, L.M. 1982. Field validation of exposure analysis modelling 

systems (EXAMS) in a flowing stream. Ch. 18. In: Dickson, K.L., Maki, 

A.W. and Cairns, J. (ed.). 1981. Modelling and Fate of Chemicals in the 

Aquatic Environment. 4th Meeting. Sci. Ann Arbor Michigan Pp. 325-346. 

 2) Painter, H.A. and Zabel, T.F. 1988. Review of the environmental safety 

of LAS. Wrc Medmendham, UK. Report No. CO 1659-M/1/EV 8658. 

 Reliability: 4 Not assignable because no details of LAS concentration were provided. 

 

(f) 

 Type: Adsorption [X]; Desorption [ ]; Volatility [ ]; Other [ ]

 Media: water - river sediments 

 Method: estimation of Kd with Freundlich equation 

 Results: Kd between 6 and 300 L/kg (5 citations), dependent on organic carbon 

content and other characteristics of the solid phase. 

Remarks: Concentration in liquid phase between 0.06 and 15 mg/L 

 Reference: Painter, H.A. and Zabel, T.F. 1988. Review of the environmental safety of 

LAS. Wrc Medmendham, UK. Report No. CO 1659-M/1/EV 8658. 

 Reliability: 4 Not assignable 

 (g) 

 Type: Adsorption [X]; Desorption [ ]; Volatility [ ]; Other [ ]

 Media: water - soil 

 Method: estimation of Kd with Freundlich equation 

 Results: Kd between 2 and 20 L/kg (3 citations), dependent on organic carbon content 

and other characteristics of the solid phase. 

Remarks: Concentration in liquid phase between 0.06 and 15 mg/L 

 Reference: Painter, H.A. and Zabel, T.F. 1988. Review of the environmental safety of 

LAS. Wrc Medmendham, UK. Report No. CO 1659-M/1/EV 8658. 

 Reliability: 4 Not assignable 

 (h) 

 Type: Adsorption [X]; Desorption [ ]; Volatility [ ]; Other [ ]

 Media: water - soil 

 Method: compilation of KF data from other sources. The Fruendlich isotherm is a 

general sorption isotherm which describes sorption behaviour and often is 

used in studies of surfactant sorption. KF is the Fruendlich isotherm 

coefficient which expresses the affinity of a surfactant for a given solid 

sorbent. As shown in the equation and table below, the exponent n is a 

measure of isotherm non-linearity. For n approaching 1, the Freundlich 

model of sorption becomes equivalent to a linear sorption model. 

 Cs = KF x Cw

n

 Results: Log KF values for a selection of C12-LAS types is shown in the table below: 

 

Log KF n Sorbent Reference 

1.7 1 EPA-B1 Hand and Williams (1987) 

2.0 1 EPA-5 Hand and Williams (1987) 

2.7 1 RC4 Hand and Williams (1987) 

3.2 1 RC3 Hand and Williams (1987) 

~0.1 1 different soils Ou et al. (1996) 

2.8 1.15 marine sediment Rubio et al. (1996) 

0.6 0.77 soil, clay loam(A) Abe and Seno (1985) 

1.4 1.20 soil, clay loam(B) Abe and Seno (1985) 

1.2 1.19 soil, sandy loam Abe and Seno (1985) 

 
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 Sorbent refers to the standard or natural soil or sediment used, as the affinity 

for sorption depends on both the chemical substance and the characteristics 

of the sorbent. All data were drawn from the original sources referenced in 

the table. 

 Remarks: The nonlinearity parameter implies that sorption affinity decreases with 

increasing LAS concentrations, which suggests that concentration 

dependency should be taken into account when assessing sorption of 

surfactants such as LAS. 

 Reference: Tolls, J. and Sijm, D.T.H.M. 2000. Estimating the properties of surfaceactive chemicals. In: Boethling, R.S. and Mackay, D. Handbook of Property 

Estimation Methods for Chemicals. Lewis Publishers. 

 Reliability: 4 Not assignable because the original articles were not directly reviewed. 

3.3.2 THEORETICAL DISTRIBUTION (FUGACITY CALCULATION) 

 

 (a) 

 Media: Air-biota [ ]; Air-biota-sediment-soil-water [X]; Soil-biota [ ]; 

Water-air [ ]; Water-biota [ ]; Water-soil [ ]

 Method: Fugacity level I [ ]; Fugacity level II [ ]; Fugacity level III [X]; Fugacity 

level IV [ ]; Other (calculation) [ ]; Other (measurement)[ ]

 Five stage Mackay-type modelling including evaluative, regional and localscale models. The first two stages involve classifying the chemical and 

quantifying the emissions into each environmental compartment. In the third 

stage, the characteristics of the chemical are determined using a quantitative 

equilibrium criterion model (EQC), which is conducted in three steps using 

levels I, II, and III versions of the model that introduce increasing 

complexity and more realistic representations of the environment. The EQC 

uses a generic, evaluative environment, which is 100,000 km2

 in area. In the 

fourth stage, ChemCAN, which is a level III model for specific regions of 

Canada, was used to predict the chemical’s fate in southern Ontario. The 

final stage was to apply local environmental models to predict environmental 

exposure concentrations. For LAS, the WW-TREAT, GRiDS, and ROUT 

models were used to predict the fate of LAS in a sewage treatment plant and 

riverine receiving waters. Estimated properties used as input parameters to 

the models are shown below for LAS (from various sources; average values; 

based on the best default environmental and physicochemical values 

available at the time of modeling): 

 Molecular mass 348 

 Air-water partition coefficient 0 

 Aerosol-water partition coefficient 100 

 Soil-water partitition coefficient (L/kg) 20 

 Sediment-water partitition coefficient (L/kg) 570 

 Fish-water partitition coefficient (L/kg) 250 

 Half-life in air (h) -- 

 Half-life in water (h) 24 

 Half-life in soil (h) 480 

 Half-life in sediment (h) 96 

 The level I calculation assumes a steady-state equilibrium partitioning of a 

fixed quantity of LAS (100,000 kg) with no reaction or advection processes. 

The level II calculation assumes a fixed input of 1000 kg/h, which is 

balanced by reaction and advection losses. Relative partitioning is identical 

to level I. For level III, the ChemCAN model assumes the following 

estimated input quantities for LAS: 
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UNEP PUBLICATIONS 153

 Total discharge to the environment (kg/yr) 1,444,000 

 Discharge to the air -- 

 Discharge to water 144,000 

 Discharge to soil 1,296,000 

 Total input in the region (kg/year) 1,440,000 

 Total input in the region (kg/hour) 164.4 

 The authors base these input quantities for the ChemCAN model on a recent 

estimate of LAS annual production in North America, western Europe and 

Japan as approximately 1.4 million tons and an annual per capita 

consumption of LAS in the United States of 1.3 kg/year. LAS is disposed 

“down-the-drain” and approximately 98% is removed in sewage treatment. 

About 30% of the LAS is removed in treatment by adsorption onto primary 

and secondary sewage solids. Over 60% of the sludge was assumed to be 

disposed of in landfills or applied to agricultural soils, thus there is the 

potential for LAS to reach the soil environment. Therefore, the level III 

model assumes a substantial discharge (90%) of LAS to soil following 

sewage treatment. Inputs considered the specific nature of nonvolatile 

surfactants such as LAS. For example, the use of Kow as a descriptor for 

organic phase-water partitioning is inappropriate for LAS and there is no 

need for a vapor pressure or air-water partition coefficient. Because LAS is a 

mixture, average properties were used as inputs to the models. In the EQC 

model, LAS is treated using the equivalence approach as the equilibrium 

criterion.

 Results: The level I and II models each resulted in LAS partitioning to air, water, soil, 

and sediment at percentages of 0%, 25.97%, 56.09%, and 17.76%, 

respectively. The overall residence time of LAS is 100 hours and removal is 

primarily by biodegradation in water (76%) and partitioning in sediment 

(13%). Thus, the impacts of LAS will be restricted to local receiving waters 

and their sediments and biota. In level III, when discharges are directly to 

water, the residence time is 33 hours and more than 99% remains in the 

water, though in shallower receiving waters more partitioning to sediments 

might be expected. When the discharge is to soil, as was assumed in the 

ChemCAN model, the residence time is 28 days because of the slower 

biodegradation rate and little transfers to other media. Based on these 

findings, the dominant fate processes are degradation rates in water and soil, 

and water-sediment transfer. 

 Using the ChemCAN 4 model, of the total amount of LAS released to the 

environment assuming the discharge rates above, the distribution and 

concentrations were predicted to be: 

 to air: 0% (0 mg/m3

) 

 dissolved in water: 0.64% (0.44 μg/m3

) 

 in soil: 99.35% (7.06 μg/kg) 

 in sediment: 0.0036% (0.00347 μg/kg) 

 

 Remarks: Based on an estimated total discharge to the environment of 1.44 x 106

kg/year (1.44 x 105

 kg to water and 1.296 x 106 kg to soil). It should be 

noted that the discharge assumptions used by the authors are highly 

conservative and likely overpredict the amount of LAS entering various 

compartments, for example, the soil compartment. This study was 

conducted by the model developer and acknowledged expert on fugucity to 

demonstrate that the approach was appropriate for different types of 

chemicals. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 154

 Reference: Mackay, D., Di Guardo, A., Paterson, S., Kicsi, G., Cowan, C. and Kane, D. 

1996. Assessment of chemical fate in the environment using evaluative, 

regional and local scale models: Illustrative application to chlorobenzene and 

linear alkylbenzene sulfonates. Environ. Toxicol. Chem. 15:1638-1648. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Media: Air-biota [ ]; Air-biota-sediment-soil-water [X]; Soil-biota [ ]; 

Water-air [ ]; Water-biota [ ]; Water-soil [ ]

 Method: Fugacity level I [ ]; Fugacity level II [ ]; Fugacity level III [X]; Fugacity 

level IV [ ]; Other (calculation) [ ]; Other (measurement)[ ] Multi-media 

model HAZCHEM derived from MacKay type level III model, including a 

water purification module (comparable to SIMPLETREAT model used by 

the Netherlands Authorities). Regional model for Europe. Includes 

probabilistic evaluation of natural variability and inaccuracy in determination 

of input parameters using Monte Carlo simulation. Input parameters held 

constant in the simulations for the LAS used in the model were based on the 

best available data at the time of modeling and are: 

 Molecular weight 347 

 Melting point (°C) 10 

 Vapor pressure (Pa) 1 x 10-10

 Solubility (mg/L) 350 

 Log Kow 2.5 

 Half-life life in air (h) 8 

 Half-life in water (h) 35 

 Half-life in soil (h) 339 

 Half-life in sediment (h) 17 

 Soil-water partitition coefficient (L/kg) 1000 

 Sediment-water partitition coefficient (L/kg) 1000 

 Suspended solids-water partitition coefficient (L/kg) 1000 

 Parameters that were varied using lognormal distributions for the Monte 

Carlo simulations included water surface and arable land fractions, depths of 

various compartments, fraction organic carbon in various compartments, 

advective residence times, temperature, and others. 

 Results: Predicted concentrations in the various compartments as defined by the model 

as shown in the table below. Degradation in the soil was not taken into 

account and the model was not calibrated. Measured concentrations in arable 

soil were generally below 1 ppm. Results are the 5th and 95th percentile values 

from the Monte Carlo analysis and the normal average. 

Average 5 percentile 95 percentile 

air (ug/m3) 3.23 E-12 -- -- 

biota (ppm) 5.99 E-2 7.11 E-3 1.95 E-1 

sediment (ppm) 4.90 E-3 3.23 E-3 1.38 E-2 

arable soil (ppm) 44.2 7.02 1.11 E+2 

suspended. matter (ppm) 3.79 0.449 12.3 

dissolved in water (mg/L) 3.79 E-3 4.49 E-4 1.23 E-2 

suspended in water (mg/L) 7.81 E-5 1.54 E-5 2.16 E-4 

 

 Remarks: Input data were the best estimates from ECETOC Task Force members, 

including detergent industries. Note the predicted average value for arable 

soil was reported in ECETOC 1993 as 4.42E-4, which is not possible given 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 155

the 5th and 95th percentile values. Therefore, the recalculated value provided 

in the IUCLID HEDSET (Year 2000 data) was used above. 

 Reference: 1) ECETOC. 1993. Environmental hazard assessment of substances. 

Technical Report No. 51, European Centre for Ecotoxicology and 

Toxicology of Chemicals, Brussels. 

 2) BKH. 1993. The use of existing toxicity data for estimation of the 

Maximum Tolerable Environmental Concentration of Linear Alkyl Benzene 

Sulfonate, Part I: Main report; Part II: Data base. Study carried out for 

ECOSOL, BKH Consulting Engineers, Delft, NL. 

 Reliability: 4 Not assignable because of uncertainty related to the input parameters. 

3.4 MODE OF DEGRADATION IN ACTUAL USE 

Remarks: Refer to other sections. 

3.5 BIODEGRADATION 

(a) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X] Marl, East treatment plant (Germany) 

Concentration: 10 mg/L 

 Medium: Semi-continuous activated sludge (SCAS) 

 Method: The Marl purification plant consists of a mechanical prepurifying area, two 

parallel trickling filters of 800 m3

 volume each, and a stimulation plant of 

106 m3

 volume, as well as mechanical final clarification. Samples were 

collected at the inlet of the trickling filters and at the exit of the final clarifier. 

Three-hour composite samples were taken for each analysis. The MBAS 

procedure was used to quantify LAS concentrations. The specific method for 

analyzing the homologues is reported in Wickbold 1964. 

 Results: Results of the percent removal by activated sludge for different alkyl chain 

length homologues and phenyl positions are shown in the following table: 

 

 Phenyl Position % Degradation 

C10

5 

4 

3 

2 

52 

68 

88 

92 

C11

6 

5 

4 

3 

2 

58 

72 

89 

93 

94 

C12

6 

5 

4 

3 

2 

81 

92 

94 

95 

95 

C13

7,6a

5 

4 

3 

2 

92 

94 

95 

96 

96 

 a Not analytically separable

 
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 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: C10 to C13 homologues of LAS with varying phenyl positions 

 Remarks: The results show that longer chain homologues are removed faster than the 

shorter chain homologues, indicating that primary biodegradation increases 

as the chain length increases. In addition, the greater the distance between 

the sulfonic group and the more distant terminal methyl group on the alkyl 

chain the faster the degradation (i.e., phenyl position 2 degrades faster than 

phenyl position 5 for the same homologue). For example, percent removal 

was 52, 68, 88 and 92% for the C10 LAS with phenyl positions 5, 4, 3, and 2, 

respectively. 

 Reference: 1) Bock, K.J. and Wickbold, R. 1966. Auswirkungen der Umstellung auf 

leicht abbaubare Waschrohstoffe in einer großtechnischen Kläranlage und im 

Vorfluter. Vom Wasser 33:242-253. 

 2) Wickbold, R. 1964. Zwischenprodukte beim Abbau eines geradkettigen 

Alkylbenzolsulfonates. Vortrage IV, Inern. Kongr. F. grenzflachenaktive 

Stoffe, Brussel. (not available for review) 

 Reliability: 2 Valid with restrictions 

 (b) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [X]; non-adapted [X]; activated sludge [X]

 Concentration of the chemical: 10 mg/L related to COD [ ]; DOC [X] test substance 

 Medium: water [ ]; water-sediment [X]; soil [ ]; sewage treatment [ ]

 Degradation: 69.6% after 28 days (acclimated inoculum) 

 66.7% after 28 days (non-acclimated inoculum) 

 Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [X] 

 Kinetics: 

Days 

% Biodegradation 

(Acclimated) 

% Biodegradation 

(non-Acclimated) 

5 14.3 9.2 

8 32.4 24.5 

12 49.5 43.6 

19 63.9 60.8 

28 69.6 66.7 

 Method: OECD 301 B, modified Sturm test, also reported as method C 5 in the Italian 

D.M. 109. The reference standard sodium benzoate was used at the same 

concentration of the tested surfactants (about 10 mg/L). The testing period 

was 28 days and during this time the testing solutions were kept in dark glass 

vessels. A supernatant solution from a sludge, which was aerated and left to 

settle, was used as an inoculum for each biodegradation test at an amount 

equal to 1% of the solution. Both the STP sludges and the laboratory 

assimilated sludges were analysed for the dry matter contents. Tests were 

conducted using acclimated or non-acclimated inocula to determine whether 

this affected ultimate biodegradation. Acclimation was achieved by running 

the laboratory activated sludge plant for seven days before testing with a 

synthetic influent containing LAS at a concentration of abourt 10 mg/L. 

Tests were conducted on LAS and three other surfactants. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: C10-13 LAS; average alkyl chain length = C11.6

 Remarks: LAS was biodegradable using both acclimated and non-acclimated inocula. 

Acclimated inocula did not significantly improve the total biodegradation, 

but did accelerate the attainment of the degradation plateau. The 10-day 

time-window criterion was missed slightly, so this study does not meet the 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 157

criteria for ready biodegradability. However, this is expected given 

biodegradation kinetic curve dynamics related to increasing dissolved 

organic carbon content because the CO2 generated during the biodegradation 

process is not totally evolved and removed from the test medium. 

 Reference: Ruffo, C., Fedrigucci, M.G., Valtorta, L., and Cavalli, L. 1999. 

Biodegradation of anionic and non-ionic surfactants by CO2 evolution. 

Acclimated and non-acclimated inoculum. Riv. It. Sostanze Grasse LXXVI: 

277-283. 

 Reliability: 1 Valid without restriction

(c) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; domestic activated sludge from Enid, OK 

Concentration: 10 mg/L 

 Medium: Semi-continuous activated sludge (SCAS) 

 Degradation: >98% in 20 days (primary biodegradation) 

 62% in 20 days (inherent biodegradation) 

 Results: readily biodeg. [ ]; inherently biodeg. [X]; under test condition no 

biodegradation observed [ ], other [ ]

 Method: 14C ring-labeled LAS and 14C alkyl-labeled C12 LAS were introduced to a 

simulated secondary waste treatment system (SCAS) following the ASTM 

and SDA standard methods. 

 GLP: Yes [ ] No [X] ? [ ]

 Test Substance: 1) LAS with the following homologue composition: C11 42%, C12 38%, C13

20%; average alkyl chain length C11.8

 2) C12 LAS 

 Remarks: In a secondary waste treatment environment, the alkyl and ring portions of 

LAS both biodegrade extensively, with the fate of the LAS alkyl and ring 

carbon nearly identical. Within the 20 day test period, 62% of the alkyl and 

ring carbon converted to carbon dioxide. 

 Reference: Nielsen, A.M. and Huddleston, R.L. 1981. Ultimate biodegradation of linear 

alkylbenzene sulfonate alkyl and ring carbon. Developments in Industrial 

Microbiology. 22:415-424. 

 Reliability: 2 Valid with restrictions 

 (d) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: Bacterial biomass obtained from the settled supernatant slurry solution of a 

fertile soil 

 Concentration: 10 mg/L 

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: See methods 

 Results: See remarks 

 Method: OECD 301E Ready Biodegradability test, with the following modifications: 

LAS was the sole source of carbon introduced (i.e., no activated sludge 

inoculum), along with an enriched level of bacterial biomass. Preliminary 

tests showed that more than 90% of the LAS disappeared within 4 days, so 

LAS was restored by adding about 10 mg/L of fresh substance every 4 days 

for 80 days. The test was stopped 4 days after the last LAS addition (i.e., at 

84 days). Specific HPLC analysis was used to measure LAS and SPCs. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: Commercial HF-type LAS with a C10-13 alkyl chain and a linearity of about 

93% (DATS <0.5%; iso-branching 5-6%). (CAS #68411-30-3); average 

alkyl chain length = C11.6

 Remarks: The final organic residue of this prolonged biodegradation test was 

characterized in detail and showed that no accumulation of iso-branching 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 158

structures had occurred. This indicates that iso-branched material of LAS is 

amenable to biodegradation as well as the linear components. 

 Reference: Cavalli, L., Cassani, G., Lazzarin, M., Maraschin, C., Nucci, G. and Valtorta, 

L. 1996b. Iso-branching of linear alkylbenzene sulphonate (LAS). Tenside 

Surf. Det. 33:393-398. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; activated sludge, domestic 

 Concentration: 10.8 mg/L related to COD [ ]; DOC [X] test substance [ ]

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 93% after 28 days 

 Results: readily biodeg. [X]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [ ]

 Kinetic: 7 day = 59% 

 14 day = 73% 

 21 day = 82% 

 Method: Directive 79/831/EEC, Appendix V, C.4-A 1990. DOC Die-Away Test. 

(OECD 301A Test). Samples were collected from an activated sludge basin 

with predominantly local municipal waste water. The final sludge 

concentration was 19.3 mg/L. Two replicates were used for the LAS test 

concentration (9.44 mg/L) with inoculum, one with inoculum without LAS, 

and two control replicates (sodium benzoate, 10.13 mg/L) with inoculum. A 

total of 900 mLs of the solutions were put into 2000 mL Erlenmeyer flasks at 

the beginning of the test. The loosely covered flasks were incubated at 21.5 

to 22.6°C in the dark on a mechanical shaker for 28 days. Samples were 

collected on days 0, 7, 14, 21 and 28 for DOC analysis. 

 GLP: Yes [X] No [ ] ? [ ] 

 Test substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS; average alkyl chain length = 

C11.6

 Remarks: LAS is readily biodegradable. The 10-day window criterion was fulfilled. 

The control substance (sodium benzoate) showed 99% degradation after 28 

days. This is a key study for ready biodegradability (see SIAR Table 4). 

 Reference: Schoeberl, P. 1993b. Bestimmung der biologischen Abbaubarkeit von 

Marlon A 390 im DOC-DIE AWAY Test. Huels Final Report No. DDA-21. 

 Reliability: 1 Valid without restriction 

 (f) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X ]; activated sludge 

 Concentration: 9.7 mg/L related to COD [ ]; DOC [ X ] test substance [ ]

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 94% after 28 days 

 Results: readily biodeg. [X]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [ ] 

 Kinetic: 3 day = 38% 

 7 day = 81% 

 14 day = 88% 

 21 day = 94% 

 Method: Directive 79/831/EEC, Appendix V, C.4-A - Year: 1990. DOC Die-Away 

Test. (OECD 301A Test). Samples were collected from an activated sludge 

basin with predominantly local municipal waste water. The final sludge 

concentration was 18.1 mg/L. Two replicates were used for the LAS test 

concentration (8.96 mg/L) with inoculum, one with inoculum without LAS, 

and two control replicates (sodium benzoate, 11.65 mg/L) with inoculum. A 
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total of 900 mLs of the solutions were put into 2000 mL Erlenmeyer flasks at 

the beginning of the test. The loosely covered flasks were incubated at 21.8 

to 22.2°C in the dark on a mechanical shaker for 28 days. Samples were 

collected on days 0, 3, 7, 14, 21, 27 and 28 for DOC analysis. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6

 Remarks: LAS is readily biodegradable. The 10-day window criterion was fulfilled. 

The control substance (sodium benzoate) showed 96% degradation after 28 

days. This is a key study for ready biodegradability (see SIAR Table 4). 

Reference: Schoeberl, P. 1993c. Bestimmung der biologischen Abbaubarkeit von 

Marlon A 390 im DOC-DIE AWAY Test. Huels Report No. DDA-32. 

Reliability: 1 Valid without restriction 

(g) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; municipal sewage treatment plant effluent. 

 Concentration: 5 mg/L related to COD [ ]; DOC [X] test substance [ ]

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 76% after 28 day 

 Results: readily biodeg. [X]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [ ]

 Method: Directive 84/449/EEC, C.3 Modified OECD screening test. (OECD 301E 

Test). 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 (h) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; activated sludge 

 Concentration: 10 mg/L related to COD [ ]; DOC [X]; test substance [ ]

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 91.6% based on DOC reduction 

 Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [X]

 Method: OECD Guideline 303 A “Simulation Test - Aerobic Sewage Treatment: 

Coupled Unit Test” 1981. The studies were carried out in the OECD 

Confirmatory Test plant at different laboratories using synthetic wastewater 

as specified in the EC Guidelines 82/242 and 82/243. The amount of 

surfactant supplied was 10 mg/ of MBAS/L. The amount of MBAS in the 

wastewater feed corresponds approximately to that detected in the feed of 

municipal sewage plants, which corresponds to about 6 mg DOC/L. Test 

periods in the different laboratories ran from 33 to 139 days. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3); average alkyl chain length = 

C11.6

 Remarks: The degradation rate of 91.6% is the mean of 10 studies conducted at 7 

different laboratories, based on DOC reduction. Since numerous studies 

have shown that not only anionic surfactants are shown in the MBAS 

analysis, the degradation plant discharge was analyzed on days 22, 24, 29 and 

30 using HPLC analysis. Results showed that the content of intact LAS was 
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UNEP PUBLICATIONS 160

< 20 μg/L, which is about 8% of the 250 μg/L MBAS content in the 

discharge. This means that the real LAS primary degradation reaches 99.8%. 

 Reference: Schoeberl, P. 1991. Coupling the OECD confirmatory test with continuous 

ecotoxicity tests. Tenside Surf. Det. 28:6-14. 

 Reliability: 2 Valid with restrictions 

 

 (i) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [ X ]; municipal sewage treatment plant effluent 

 Concentration: 5 mg/L related to COD [ ]; DOC [ ]; test substance [X] MBAS 

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 95% after 19 days 

 Results: readily biodeg. [X]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [ ]

 Method: OECD Screening Test according to “Verordnung ueber die Abbaubarkeit 

anionischer und nichtionischer grenzflaechenaktiver Stoffe in Wasch- und 

Reinigungsmittel vom 30.1.1977”. Bundesgesetzblatt Teil I, S. 244. 1977 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 (j) 

 Type: aerobic [X ]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; synthetic sewage 

 Concentration: 19.2 mg/L related to COD [ ]; DOC [ ]; test substance [X]

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 92.3% based on DOC reduction 

 Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [X]

 Method: OECD-Guideline 303A coupled units test. The studies were carried out in the 

OECD Confirmatory Test plant at different laboratories using synthetic 

wastewater as specified in the EC Guidelines 82/242 and 82/243. In these 

studies, LAS was added to the test at 10 mg/L. Test periods in the different 

laboratories ran from 33 to 139 days. Test temperature ranged from 19.6-

23.0o

C. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Marlon A390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.8

 Remarks: The degradation rate of 92.3% is the mean of 10 studies conducted at 7 

different laboratories, based on DOC reduction, with LAS added to the 

confirmatory test plant. 

 Reference: 1) Schoeberl, P. 1991. Coupling the OECD confirmatory test with 

continuous ecotoxicity tests. Tenside Surf. Det. 28:6-14. 

 2) European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 2 Valid with restrictions 

 

 (k) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; 

 Concentration: 10 mg/L 
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 Medium: related to COD [ ]; DOC [ ]; test substance [X] as MBAS 

 water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 99.8% after 3 days (for sewage dose of 1.0 mg/L) 

 89.4% after 7 days (for sewage dose of 0.5 mg/L) 

 74.5% after 7 days (no sewage dose, but aerated) 

 40.7% after 7 days (no sewage, non aerated) 

 Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [X] primary biodegradation 

 Method: Samples from test flasks were taken at 12 hour intervals and the detergent 

concentration expressed as methylene blue active substance was determined. 

The initial concentration of detergent was 10 mg/L. The degradation of LAS 

was evaluated in raw canal water and in canal water seeded with either 0.5 

ml/L or 1.0 ml/L sewage from the Ismalia sewage treatment plant. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Commercial LAS detergent (provided by Merck, Darmstadt, Germany); 

likely average alkyl chain length = C11.6 

 Remarks: Medium was Ismailia Canal water (Cairo, Egypt). ABS and a 1:1 mixture of 

ABS:LAS were also examined. Degradation of LAS was rapid, whereas 

degradation of ABS and the 1:1 mixture of ABS/LAS was slower. In all 

cases, aeration and addition of sewage microflora enhanced degradation. 

 Reference: Abdel-Shafy, H.I., Azzam, A.M. and El-Gamal, I.M. 1988. Studies on the 

degradation of synthetic detergents by sewage. Bull. Environ. Contam. 

Toxicol. 41:310-316. 

 Reliability: 2 Valid with restrictions 

 (l) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; 

 Concentration: 15 mg/L related to COD [ ]; DOC [ ]; test substance [X] HPLC

 Medium: water [ ]; water-sediment [ ]; soil [ ]; sewage treatment [X]

 Degradation: 95% after 28 days (LAS-A) 

 98% after 28 days (LAS-B) 

 Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [X]

 Method: OECD303A coupled units test modified by AIS/CESIO "ad hoc" working 

group. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Two C10-13 LAS commercial products as described in the remarks. 

 Remarks: LAS-A, produced by the HF process, was 93% linear with 0.5% tetralins and 

6.5% iso-branching and the following homologue distribution of the alkyl 

chain: C10 15%, C11 34%, C12 31%, C13 20% (average alkyl chain length = 

C11.56). LAS-B, produced by the AlCl3 process, was 98% linear with 0.5% 

tetralins and 1.5% iso-branching and the following homologue distribution of 

the alkyl chain: C10 15%, C11 29%, C12 32%, C13 24%, average alkyl chain 

length = C11.65. HPLC methods specific to LAS were used to directly 

measure the test substances (LAS as well as the biodegradable 

intermediates). The ultimate biodegradation rates determined by HPLC are 

>10% higher than those obtained using DOC determination. The studies 

were conducted according to high standards and should be considered 

reliable. 

 Reference: Cavalli, L., Cassani, G. and Lazzarin, M. 1996a. Biodegradation of linear 

alkylbenzene sulphonate (LAS) and alcohol ethoxylate (AE). Tenside Surf. 

Det. 33:158-165. 

 Reliability: 2 Valid with restrictions 

 

 (m) 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [ ]; None Stated 

 Concentration: 15 mg/L related to COD [ ]; DOC [ ]; test substance [X] HPLC

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 95% after 6 days 

 Results: readily biodeg. [ ]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [X]

 Method: LAS and water collected from a briny pond (salinity: 9.5 g/L) were tested in 

an aerated cylindrical reactor at 21o

C. Samples were removed periodically 

and analyzed for parent compound and metabolites by HPLC. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (CAS #25155-30-0); activity: >99%; average alkyl chain length = C11.6 

 Remarks: The half-life of LAS was 1.5 days. The HPLC method employed accurately 

defines the metabolites formed by primary biodegradation. All metabolites 

were not persistent and rapidly underwent further biodegradation. 

 Reference: Sarrazin, L., Arnoux, A., Rebouillon, P. and Monod, J.L. 1997. 

Biodegradation of linear alkylbenzenesulfonate (LAS) in briny water and 

identification of metabolites using HPLC analysis by direct injection of 

samples. Toxicological and Environmental Chemistry. 58:209-216. 

 Reliability: 2 Valid with restrictions 

 

(n) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X]; activated sludge 

 Concentration: 1 mg/L related to COD [ ]; DOC [ ]; test substance [X]

 Medium: Activated sludge 

 Degradation: >96% after 6 hours 

 Results: Primary and complete biodegradation were described by a first-order model, 

with rate constants of 0.96-1.10/h (t1⁄2 = 0.63–0.72 h) for primary loss and 

0.50-0.53/h (t1⁄2 = 1.30–1.38 h) for complete degradation. 

 Method: Radiolabeled LAS was dosed at an environmentally relevant concentration 

into biotic and abiotic activated sludge. Activated sludge mixed liquor was 

used from two STP (Polk Run and Sycamore) near Cincinnati. Standard 

methods were used and the test flasks (reactors) were maintained at 20+

/-2oC. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: 14C [uniform ring] C12 LAS 

 Reference: Federle, T.W. and Itrich, N.R. 1997. Comprehensive approach for assessing 

the kinetics of primary and ultimate biodegradation of chemicals in activated 

sludge: Application to linear alkylbenzene sulfonate. Environ. Sci. Technol. 

31:1178-1184. 

 Reliability: 2 Valid with restrictions 

 (o) 

 Type: aerobic [ ]; anaerobic [X]

 Methods: Experiments were conducted in which enriched cultures of anaerobic bacteria 

were provided with 60 μmole/L LAS as the sole source of sulfur. Conditions 

were maintained anoxic in salts-medium containing several sources of 

carbon. 

 Results: Strain RZ LAS, an anaerobic bacteria, was isolated from wastewater 

treatment plants in Germany. RZLAS was shown to degrade LAS, 

indicating that microorganisms able to metabolize LAS in anaerobic 

conditions exist in nature. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: Commercial C10-13 LAS (CAS #68411-30-3; average alkyl chain length = 

C11.6) and C12 LAS (pure homologue) 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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 Reference: Denger, K. and Cook, A.M. 1999. Linear alkylbenzene sulphonate (LAS) 

bioavailable to anaerobic bacteria as a source of sulphur. Journal of Applied 

Microbiology. 86:165-168. 

 Reliability: 2 Valid with restrictions 

 (p) 

 Type: aerobic [ ]; anaerobic [X]

 Inoculum: adapted [ ]; non-adapted [X]; granular sludge 

 Concentration: 9 concentrations ranging from 12.5 to 350 mg/bottle 

 Medium: Liquid 

 Degradation: 5-44% after 14 days 

 Method: Upflow Anaerobic Sludge Blanket (UASB) type reactors with a working 

volume of 315 mL in serum type glass bottles were used to measure 

degradation. The bottles were incubated at 30+

/-2oC for 14 days. The sludge 

concentration was 1.5 g/L. Methane production was measured daily using 

both the Head Space method and the Displacement method. LAS was 

specifically determined using HPLC. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: LAS, sodium salt derived from commercial LAB with the homologue 

distribution: <C10 0.7%, C10 8.4%, C11 40.9%, C12 32.5%, C13 16.6%, and C14

0.9%. Final molecular weight of 341.5. Average alkyl chain length = C11.54

 Remarks: The study determined an IC50 of 40 to 150 mg/L as inhibitory to anaerobic 

microbial populations. LAS concentrations are usually found in anaerobic 

digestors at 5-25 g/kg, which is about an order of magnitude lower than the 

observed IC50 values. The study demonstrates that LAS anaerobic 

biodegradation does occur under conditions that are not sulphur-limited, 

using anaerobic digestor sludge and specific HPLC methods to measure the 

loss of parent material. 

 Reference: Sanz, J.L., Rodriguez, M., Amils, R., Berna, J.L., de Ferrer, J. and Moreno, 

A. 1999. Anaerobic biodegradation of LAS (Linear Alkylbenzene 

Sulfonate): Inhibition of the methanogenic process. La Rivista Holiana 

Delle Sostanze Grasse. LXXVI:307-311. 

 Reliability: 2 Valid with restrictions 

 (q) 

 Type: aerobic [ ]; anaerobic [X]

 Inoculum: Activated sludge 

 Medium: Sewage sludge 

 Degradation: 30-93% after 250 days; 50% in a second 90 day experiment 

 Results: LAS biodegrades under strict anaerobic conditions. 

 Method: The standard ECETOC-28 method, which measures the pressure of the 

biogas as an indicator of anaerobic degradation, was extended to 250 days 

and supplemented with specific HPLC analysis of LAS concentrations. 

Testing bottles were prepared in triplicate and monitored for the 

biodegradation of LAS already present in the sludge without extra LAS 

being added to the system. A second experiment was also based on the 

ECETOC-28 method, with several modifications used to further control the 

anaerobic test conditions. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: LAS, as exists in sewage sludge 

 Remarks: Specific HPLC analysis (loss of LAS) confirms that LAS undergoes primary 

biodegradation anaerobically in the standard ECETOC-28, although 

increased gas production (mineralization) was not observed. A redisolution 

of precipitated adsorbed LAS seemed to occur in the digestion process. The 

product in liquid solution is probably the fraction being degraded. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 164

 Reference: Prats, D., Rodriquez, M., Llamas, J.M., De La Muela, M.A., de Ferrer, J., 

Morena, A. and Berna, J.L. 2000. The use of specific analytical methods to 

assess the anaerobic biodegradation of LAS. 5th World CESIO Congress 

V2:1655-1658, Firenze, Italy. 

 Reliability: 2 Valid with restrictions 

(r) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: Trickling filters 

 Medium: Sewage sludge 

 Results: ROC supported sulfur-limited growth of P. putida. Extensive desulfonation 

of ROC was observed. 

 Method: Other studies have confirmed that LAS is completely biodegradable in 

trickling filters and by- products in commercial LAS (e.g., DATS, SPC) are 

subject to biotransformation to nondegraded compounds termed refractory 

organic carbon (ROC). The current study investigated the further 

desulfonation of ROC by a strain of Pseudomonas putida. ROC was 

generated from commercial LAS, which served as a carbon source, in a 

trickling filter and isolated by solid-phase extraction. The solution of ROC 

was then used as a potential sulfur source for the growth of P. putida. 

Experiments were conducted in triplicate at 30°C and cultures were aerated 

on an orbital shaker. Dissolved Organic Carbon was measured using a total 

organic carbon analyzer and HPLC. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: Commercial LAS (Sirene 113) 

 Remarks: Earlier work shows that the biodegradation and biotransformation of 

commercial LAS as a carbon source for growth leads to a residue of 

sulfonated aromatic compounds, termed refractory organic carbon (ROC), 

from the synthetic by-products. This study demonstrates that this ROC, after 

separation from sulfate ion, is utilized extensively as a sulfur source for 

bacterial growth. The products of desulfonation are expected to be 

biodegradable. 

 Reference: Mampel, J., Hitzer, T., Ritter, A. and Cook, A.M. 1998. Desulfonation of 

biotransformation products from commercial linear alkylbenzene sulfonates. 

Environ. Toxicol. Chem. 17:1960-1963. 

 Reliability: 2 Valid with restrictions 

 

 (s) 

 Type: aerobic [ ]; anaerobic [X]

 Inoculum: adapted [ ]; non-adapted [ ]; other [X]; lake sediments 

 Concentration: 20, 100, and 200 mg/L 

 Medium: Water 

 Results: Degradation occurred under anaerobic conditions when exposed to inoculum 

obtained from lake sediments. In addition, inocula that were found in aerobic 

environments such as compost and activated sludge from a wastewater 

treatment plant also showed capability of anaerobic degradation of LAS. 

 Method: Tests were performed in batch serum vials under anaerobic conditions. The 

vials were filled with the appropriate pH 7 medium, autoclaved at 140o

C for 

30 minutes, and inoculated with 5 to 10% of the respective inocula. Inocula 

originated from several different natural environments and from anaerobic 

reactors. LAS was added at three different concentrations (20, 100, and 200 

mg/L) plus three sets of controls, all in triplicate. Incubation time was 2 

months. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: Mixture of LAS with an alkyl chain length of 9 to 13 units; likely average 

alkyl chain length = C11.6
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 165

 Remarks: This paper indicates qualitatively that LAS undergoes anaerobic degradation, 

but no quantitative results are presented. 

 Reference: Angelidaki, I., Mogenen, A.S. and Ahring, B.K. 2000b. Degradation of 

organic contaminants found in organic waste. Biodegradation. 11:377-383. 

 Reliability: 2 Valid with restrictions 

 (t) 

 Type: aerobic [ ]; anaerobic [X]

 Inoculum: Activated sludge 

 Concentration: 100 mg/L 

 Medium: water [ ]; water-sediment [ ]; soil [ ]; sewage treatment [X]

 Degradation: Transformation of C12 LAS occurred under anaerobic conditions. The degree 

of transformation varied between 14 to 25%. 

 Methods: Two lab-scale continuous stirred tank reactors (CSTR) were set up with 

automatic, semi-continuous feeding and were run under mesophilic 

conditions (37o

C) with a hydraulic retention time of 15 days. The reactors 

were started with anaerobic stabilizer sewage sludge and operated for several 

months before the experiment started. The feed was diluted sludge at a total 

solids concentration of 20 g TS/L. The sludge was spiked with C12 LAS at a 

concentration of 100 mg/L and the two reactors were operated similarly for 

36 days. After this period, the LAS concentration in reactor 1 was increased 

to 268 mg/L, while for reactor 2 the influent TS was decreased to 11.4 g 

TS/L, and both reactors continued to operate for a total of 90 days (including 

the original 36 days). 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: C12 LAS (pure homologue) 

 Remarks: A clear correlation was shown between degradation of organic matter 

contained in the sludge and anaerobic degradation of LAS, giving an 

increase in transformation with the higher the reduction of organic matter. 

Transformation was limited by bioavailability due to sorption of LAS (i.e., 

only the bioavailable fraction of LAS is transformed by anaerobic digestion). 

When the reduction degree of the organic matter increased from 22% to 

28%, the transformation degree of C12 LAS increased from 14% to 20%. 

Decreasing the total solids concentration of the influent sludge or increasing 

the spiked concentration of C12 LAS did not significantly alter the degree of 

LAS transformation. 

 Reference: Angelidaki, I., Haagensen, F. and Ahring, B.K. 2000a. Anaerobic 

transformation of LAS in continuous stirred tank reactors treating sewage 

sludge. 5th World CESIO Congress. V.2:1551-1557, Firenze, Italy. 

 Reliability: 2 Valid with restrictions 

 

 (u) 

 Type: aerobic [ X]; anaerobic [ ]

 Medium coastal sea water 

 Concentration: 5 mg/L related to test substance 

 Results: LAS primary degradation half-lives ranged from 3.4 to 13.8 days, with 4-9 

days being the most frequent values. 

 Method: Coastal sea water from the Mediterranean Sea was collected from three areas 

in Spain (Barceloneta, Ebro delta, and Sant Feliu de Guixols, Girona). 

Samples of 1.5- L were placed in 3-L flasks and incubated in the dark at 20o

C 

with orbital shaking (100 rpm) for 30 days. Viable bacteria were determined 

by plate counts on marine agar media, while total bacteria were determined 

by flow cytometry after SYTO-13 staining. LAS degradation was monitored 

by HPLC. A reference substance was not used. LAS quantification was 

based on an external standard. 

 GLP: Yes [ ] No [ ] ? [X]
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 166

 Test Substance: C10-14 LAS, activity 66.62%; average alkyl chain length = C11.7

 Remarks: In most cases, sea water samples showed a similar evolution of 

bacterioplankton over time, characterized by three phases: (a) a progressive 

increase in bacterial density; (b) a later decrease; and (c) a fluctuating 

stationary phase. Bacterioplankton degraded the LAS by growing to 

populations with a high percentage of viable bacteria. The bacteria were 

readily grazed by protozoa, preventing anomalous high bacterial growth and 

ensuring the later channeling of LAS carbon to upper trophic levels. 

 Reference: Vives-Rego, J., Lopez-Amoros, R., Guindulain, T., Garcia, M.T., Comas, J., 

and Sanchez-Leal, J. 2000. Microbial aspects of linear alkylbenzene 

sulfonate degradation in coastal water. Journal of Surfactants and 

Detergents. 3:303-308. 

 Reliability: 2 Valid with restrictions 

 (v) 

 Type: Respirometer 

 Method: Degradation of LAS in Ohio River water collected below the discharge of a 

municipal wastewater treatment plant (Muddy Creek, OH) was measured in 

an electrolytic respirometer. Background LAS concentrations were less than 

0.5 mg/L. Oxygen consumption over time was determined at five LAS 

concentrations (5, 10, 20, 40, and 80 mg/L) plus a control until plateau values 

were reached. The maximum initial rates of oxygen uptake were calculated 

based on methods described in Larson and Perry (1981). 

 Results: LAS degradation was not affected in river water until the LAS concentration 

exceeded 10 mg/L. The degradation was partially affected at 20 mg/L but 

was not completely inhibited until 40 mg/L. 

 Substance: LAS; average chain length C11.6. 

 Remarks: The level at which inhibition of degradation was complete (40 mg/L) is 

significantly higher than the levels observed in model ecosystem studies 

conducted by these researchers [see 4.7 (h) and (i)]. 

 Reference: 1) Larson, R.J. and Maki, A.W. 1982. Effect of LAS on the structure and 

function of microbial communities in model ecosystems. Aquatic 

Toxicology and Hazard Assessment: Fifth Conference, ASTM STP 766, 

Pearson, J.G., Foster, R.B., and Bishop, W.E., Eds., American Society for 

Testing and Materials, pp. 120-136. 

 2) Maki, A.W. 1981. A laboratory model ecosystem approach to 

environmental fate and effects studies. Unpublished Internal Report, 

Environmental Safety Department Procter & Gamble Company, Cincinnati, 

Ohio. 

 3) Larson, R.J. and Perry, R.L. 1981. Water Research 15:697-702. 

 Reliability: 2 Valid with restrictions 

 (w) 

Type: aerobic [X]; anaerobic [ ]

 Substance: LAS 

 Remarks: The biodegradation of LAS has been thoroughly studied for its primary and 

total degradation and catabolism. It is mineralized biologically to form 

carbon dioxide, water and sulphate. Using UV spectroscopic analysis, 

Swisher (1987) and others showed the aromatic ring to be degradable up to 

80%. Using the more reliable tracer technique with 14C-ring labelled LAS, it 

was determined that degradation of the ring is predominantly between 50 and 

80%. Further studies have shown that LAS degradation proceeds through 

oxidative conversion of the methyl groups of the alkyl chain into a carboxyl 

group (ω-oxidation), oxidative shortening of the alkyl chain by 2-carbon 

units (β-oxidation), oxidative ring splitting, then cleavage of the carbonsulfur bond. This process forms sulfophenyl carboxylates (SPCs) as 
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UNEP PUBLICATIONS 167

biodegradation intermediates. The first detectable degradation product of 

LAS is ω-carboxylate. For example, Huddleston and Allred (1963) detected 

sulfophenyl decanoic acid as a catabolite of 2-benzenedecasulfonate. 

Oxidative degradation of the alkyl chain begins as soon as LAS has been 

converted into sulfophenyl carboxylic acid. The principal degradation 

pathway is β-oxidation. The rate of biodegradation is inversely related to the 

distance between the terminal alkyl-methyl group and the point of benzene 

ring attachment. Simple branching does not impair the oxidation of 

alkylbenzene, though more complex branching does decrease the rate. 

 Reference: 1) Swisher, R.D. 1987. Surfactant Biodegradation, second edition. Surfactant 

Science Series, Volume 18. Marcel Dekker, Inc. New York. 

 2) Schoeberl, P. 1989. Basic principles of LAS biodegradation. Tenside Surf. 

Detergents 26:86-94. 

 3) Huddleston, R.L. and Allred, R.C. 1963. Microbial oxidation of sulfonated 

alkylbenzenes. Dev. Ind. Microbiol. 4:24-38. 

 Reliability: 2 Valid with restrictions

 (x) 

 Type: aerobic [X]; anaerobic [ ]

 Method: Dialkyltetralin sulfonates (DATS) and LAS with single methyl branching on 

the alkyl chains (iso-LAS) are minor components in commercial LAS. In this 

study, DATS and iso-lAS were synthesized and exposed to simulated 

activated sludge, soil, and receiving water environments. In addition, the 

effluents coming from activated sludge treatment, which contained 

biodegradation intermediates, were exposed to simulated receiving water 

environments. Radiolabeled LAS, DATS and iso-LAS were used and all 

samples were analyzed using chemical-specific HPLC procedures. Surface 

soils were collected at three locations to represent “pristine” soil, sludgeamended soil, and gray water contaminated soil from the top of a percolation 

bed that receives surface applications of laundry water from a Laundromat. 

All samples were screened to remove vegetation, rocks and debris, and mixed 

with a mineral salts medium containing the test substance. Sediment samples 

were collected from the upper inch of a small stream that received effluent 

from a domestic wastewater treatment plant. Periphyton samples were 

collected as rocks coated with heavy growth from the same stream locations 

as the water and sediment samples. Each test system consisted of duplicate 

test flasks and a control flask. Tests lasted at least 30 days. For assessing 

biodegradation, the porous pot method was used in a simulated wastewater 

activated sludge modified from ASTM test method E1798-96. A 21-day 

acclimation phase was followed by a 15-day test phase in which 

radioactivities in C02, liquids and solids, and effluent total suspended solids 

and COD were determined each day. Radiochemical recoveries for the 

porous pot test were calculated. For the die-away tests with porous pot 

effluents, the combined effluents from individual units were tested for 

mineralization of radiolabeled parent and intermediate compounds. All tests 

were run at least 30 days and the radioactivities measured at the end of each 

test. 

 Results: Results indicate that radiolabeled DATS and iso-LAS is mineralized by 

indigenous microbial populations in laboratory simulations of aquatic and 

soil environments. Half-lives ranged from 2 to 20 days. In addition, upon 

exposure to laboratory activated sludge treatment, most iso-LAS compounds 

showed >98% parent compound removal, extensive mineralization (>50%), 

and 79-90% ultimate biodegradation. Activated sludge treatment of DATS 

resulted in >98% removal, 3-12% ultimate biodegradation, and apparent 

formation of carboxylated biodegradation intermediates that accounted for 

88-97% of the original material. These intermediatel continued to mineralize 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 168

in simulated receiving water and soil environments at rates similar to that of 

sulfophenyl carboxylate (SPC) intermediates of a standard LAS. 

 Test Substances: 14C-benzene ring labeled C12 LAS (97.5% radiochemical purity); 14C-benzene 

ring labeled iso-LAS of the following types (IA, 97.8% purity; IB, 77.6% 

purity; IIA, 94.7% purity; IIB, 97.5% purity); 14C-benzene ring labeled 

DATS (97.3% purity), plus the non-labeled versions of the same. 

 Reference: Nielsen, A.M., Britton, L.N., Beall, C.E., McCormick, T.P. and Russell, G.L. 

1997. Biodegradation of coproducts of commercial linear alkylbenzene 

sulfonate. Environ. Sci. Technol. 31:3397-3404. 

 Reliability: 2 Valid with restrictions 

 (y) 

 Type: aerobic [X]; anaerobic [ ]

 Method: OECD 301E. The study was designed to investigate the biodegradation of a 

relatively high iso-branched form of commercial LAS. The test was a 

prolonged batch-biodegradation experiment in which the material is kept 

“alive” for 80 days and in which the test compound present in a mineral salts 

medium is the sole carbon source. An enriched level of bacterial biomass, 

three times the amount recommended, was added at the test start using an 

inoculum obtained from the settled supernatant slurry solution of a fertile 

soil, without any previous exposure to the test compound. LAS was 

maintained by adding about 0 mg/L of fresh substance every four days for 80 

days. After 80 days the test solution was sampled, centrifuged, sterilized 

with HgCl2 solution and analyzed with a chemical specific HPLC method 

with fluorescence detection. 

 Results: Results indicate a residual LAS amount of 1.5 mg/L and SPC intermediate 

amount of 28.7 mg/L at the end of the 80 day study. Four distinct SPCs 

originating from the linear components of LAS were formed from the 

biodegradation experiment, and made up most of the organic residue. No 

evidence of structures related to the iso-branched material was found in the 

residue, therefore no accumulation of these materials is indicated. The isobranched component of LAS and the corresponding SPCs mineralized at 

rates as fast as the linear components. 

 Test Substances: Commercial LAS (HF type) with a C10-C13 alkyl chain and a linearity of 

about 93%, with a low DATS content (<0.5%) and a relatively high iso-LAS 

content (6.5%). 

 Reference: Cavalli, L., Cassani, G., Lazzarin, M., Maraschin, C., Nucci, G., and 

Valtorta, L. 1996. Iso-branching of linear alkylbenzene sulphonate (LAS). 

Tenside Surf. Det. 33:393-398. 

 Reliability: 2 Valid with restrictions 

 (z) 

 Type: aerobic [X]; anaerobic [ ]

 Inoculum: adapted [ ]; non-adapted [X ]; activated sludge 

 Concentration: 34.3 mg/L related to COD [ ]; DOC [ X ] test substance [ ]

 Medium: water [X]; water-sediment [ ]; soil [ ]; sewage treatment [ ]

 Degradation: 85% after 29 days 

 Results: readily biodeg. [X]; inherently biodeg. [ ]; under test condition no 

biodegradation observed [ ], other [ ] 

 Kinetic: 0 day = -1% 

 2 day = -2% 

 5 day = 22% 

 9 day = 52% 

 12 day = 70% 

 14 day = 70% 

 21 day = 78% 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 169

 28 day = 83% 

 29 day = 85% 

 Method: OECD Test Guideline 301B and EC Directive 92/69/EEC C.4-C. Modified 

Sturm Test.. The test substance was added to a defined liquid mineral 

medium which was inoclulated with an activated-sludge inoculum and 

aerated at 19.7-21.9°C (mean 21.1°C). The inoculum used was activated 

non-adapted sludge from the Marl-Ost municipal sewage treatment plant. 

The inoculum had a bacterial count of 81 x 104

 CFU/mL as determined by 

the Koch pour-plate method. The CO2 released was bound in the form of 

sodium carbonate in sodium hydroxide solution. Samples were collected and 

analyzed in duplicate for bound CO2 by TIC analysis after 0, 2, 5, 9, 12, 14, 

21, 28 and 29 days. Sodium benzoate was used as a suitable control 

substance to monitor the activity of the inoculum. On the 29th day, residual 

dissolved CO2 was expelled by acidification. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Marlon A 365 WEL 6859 (CAS #68411-30-3) C10-13 LAS, average alkyl 

chain length = C11.6; Activity: 65% 

 Remarks: LAS is readily biodegradable. The 10-day window criterion was fulfilled. 

The control substance (sodium benzoate) showed 89% degradation after 29 

days. This is a key study for ready biodegradability (see SIAR Table 4). 

Reference: Enste-Diefenbach, R.. 2002. Marlon A 365 WEL 6859: Determination of 

biodegradability in the modified Sturm test.. Infracor GmbH Analytical 

Tehcnical Services, Report ST-204/02. 

Reliability: 1 Valid without restriction 

3.6 BOD5, COD OR RATIO BOD5/COD

 BOD5

 Method: DIN 38H03, Part 1. Bestimmung des biochemischen Sauerstoffbedarfs in 5 

Tagen nach den Verduennungsprinzip. 

 Value: <10 mg O2/g for both Marlon A 350 and Marlon A 375 

 GLP: Yes [ ] No [ ] ? [X]

 COD

 Method: DIN 38H03, Part 1 

 Values: 1151 and 1760 mg O2/g for Marlon A 350 and Marlon A 375, respectively. 

 GLP: Yes [ ] No [ ] ? [X] 

 Ratio BOD5/COD: < 0.005 

 Remarks: Marlon A 350 (C10-13 LAS, average chain length = 11.6, 50% a.i.) 

 Marlon A 375 (C10-13 LAS, average chain length = 11.6, 75% a.i.) 

 The extended term BOD determinations yield 60 to 70% of COD. The 

 substance is degradable. 

 Reference: European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts (CAS #68411-30-3). Year 2000 CD-ROM edition, citing data 

by Huels AG Marl. 

 Reliability: 4 Not assignable 

3.7 BIOACCUMULATION 

(a) 

 Species: Pimephales promelas (fish, fresh water) 

 Exposure period: 48, 168, 192 hours 

 Temperature: Per Protocol 
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 Concentration: 2.7 and 4.1 μM 

 BCF: Values of Steady-State Bioconcentration Factor (BCFss) and Average Length 

of Alkyl Chain (nC,Av) are shown in the following table. 

 

expt comp* BCFss

L/kg nC,Av

C10-2 1.7 

C11-2 5.8 

C12-2 47.6 A 

C13-2 353.8 

10.8 

C11-5 6.1 

C12-2 99.1 

C12-5 10.0 B 

C13-5 34.0 

11.7 

C11-5 9.8 

C12-2 168.4 

C12-3 42.1 C 

C12-6 31.9 

11.4 

C10-2 6.0 

C11-2 31.9 

C12-2 211.5 

C13-2 987.2 

C10-in 3.0 

C11-in 9.1 

C12-in 29.9 

D 

C13-in 112.4 

10.6 

 *In the format Cn-m, n and m are the length of the alkyl chain and the position at 

which the sulfophenyl moiety is substituted to the alkyl chain, respectively. 

 Elimination: Yes [X] No [ ] ? [ ]

 Method: OECD 305 E. The exposure phase in Experiment A was 48-hours. The 

exposure phase in Experiments B-D ranged from 168 to 192 hours. Due to 

the rapid equilibrium demonstrated in these studies, a longer exposure period 

was not needed. Fish were then transferred to untreated water for the 

depuration phase (duration not stated). 

 Type of test: calculated [ ]; measured [X] 

 static [ ]; semi-static [ ]; flow-through [X]

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (C10-13), tested individually and as mixtures, activity: >97.4% 

 Remarks: As shown in the table, BCF values ranged between 2-1000 L/kg. 

Experiments A, B and D showed that BCFs increase with increasing alkyl 

chain length for a given isomer. In addition, the results of Experiments B and 

C demonstrate that the closer the p-sulfophenyl moiety is positioned to the 

terminal carbon of the alkyl chain, the higher the BCF. However, alkyl chain 

length has a much bigger effect than does the phenyl position. To address 

differences in composition of mixtures, bioconcentration potential was 

calculated for a mixture typical of LAS in European detergent formulations 

(C10 12%, C11 29%, C12 34%, C13 24%; average alkyl chain length = C11.6) 

and a mixture typical of LAS in filtered Mississippi river water (C10 45%, C11

23%, C12 23%, C13 2%; average chain length = C10.8), using BCF values for 

the individual components. This calculation of BCF for the typical mixtures 

was done using the following equation developed in the above testing: 

 (ΣCf,i/ΣCw,i)rel = Σ(øi,w · BCFi,rel) 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 171

 The BCFs were 87 L/kg for a standard mixture typical of LAS in European 

detergent formulations (average alkyl chain length = C11.6) and 22 L/kg for a 

representative environmental sample (filtered Mississippi river water, 

average alkyl chain length = C10.8), indicating that the bioconcentration 

potential of LAS is low and is decreased by environmental processes such as 

biodegradation and absorption, which reduce aquatic concentrations. 

 Reference: Tolls, J., Haller, M., DeGraaf, I., Thijssenk, M.A.T.C. and Sijm, D.T.H.M. 

1997. Bioconcentration of LAS: Experimental determination and 

extrapolation to environmental mixtures. Environ. Sci. Technol. 31:3426-

3431. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Species: Lepomis macrochirus

 Exposure Period: 21 days 

 Temperature: 17+

/-1oC 

 Concentration: 0.5 mg/L 

 BCF: 104 (whole body); 36 (muscle) 

 Elimination: Yes 

 Method: Bluegill sunfish (avg wt. 4.0 g; avg length 68 mm) were placed in a 60 liter 

aquarium (375 fish total) and maintained for 21 days. A second aquarium 

held 100 control fish. Fish were fed daily with a dry pelleted trout chow 

ration of approximately 2% of body weight. Water samples were removed 

periodically for radiometric analysis of 14C-labeled LAS. Four fish were 

removed on each of days 1, 2, 3, 5, 7, 9, 11 and 14 for radiometric analysis. 

 Type of test: calculated [ ]; measured [ ]; static [ ]; semi-static [ ]; flow-through [X]

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS (CAS #68411-30-3) with the following alkyl chain length 

distribution: C11 45%, C12 36.5%, C13 18.5%. Average chain length was 11.7 

and molecular weight was 344. 

 Remarks: The site of greatest concentration was the gall bladder with a BCF of 5000, 

based on total radiolabeled materials. The BCFs for liver, gills and viscera, 

remaining carcass, and blood ranged from 64 to 283. Clearance of 

radiolabeled materials was rapid with half-lives of 2 to 5 days. However, no 

quantitative conclusions specific to LAS can be drawn from these data, as 

total radiolabeled materials were measured, and these likely include LAS 

metabolites. 

 Reference: Kimerle, R.A., Macek, K.J., Sleight, B.H. and Burrows, M.E. 1981. 

Bioconcentration of linear alkylbenzene sulfonate (LAS) in bluegill 

(Lepomis macrochirus). Wat. Res. 15:251-256. 

 Reliability: 2 Valid with restrictions

3.8 ADDITIONAL REMARKS 

A. Sewage treatment

 (a) 

 Results: LAS removal in sewers due to biodegradation can reach as high as 50% of 

the total LAS load when the sewer system is properly aerated. 

 Method: Integrated composite samples were collected in November and December 

1988 from the sewer system of Estepona (Malaga), Spain. LAS was 

analyzed using a specific HPLC technique. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 172

 Remarks: This study demonstrates that significant biodegradation of LAS occurs prior 

to reaching wastewater treatment plants. Additional removal (up to >95%) 

occurs in the plants themselves. 

 Reference: Moreno, A., de Ferrer, J. and Berna, J.L. 1990. Biodegradability of LAS in a 

sewer system. Tenside Surf. Det. 27:312-315. 

 Reliability: 2 Valid with restrictions 

 

(b) 

 Results: The average removal rate for LAS in activated sludge treatment was > 99%. 

A lower and more variable rate was observed in trickling filter treatment 

plants with an average removal of 82% for LAS. 

 Remarks: Samples were collected from six trickling filter and four activated sludge 

treatment plants located in the midwestern United States. 

 Reference: McAvoy, D.C., Dyer, S.D., Fendinger, N.J., Eckhoff, W.S., Lawrence, D.L. 

and Begley, W.M. 1998. Removal of alcohol ethoxylates, alkyl ethoxylate 

sulfates, and linear alkylbenzene sulfonates in wastewater treatment. 

Environ. Toxicol. Chem. 17:1705-1711. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Results: The model predicted average removal of LAS from wastewater treatment 

plants is 99.2%. Predicted 90th-percentile concentrations at 1,000 m 

downstream from the sewage outfall, based on actual measured raw sewage 

concentrations and actual measured effluent calculations, ranged from 3.7 to 

9.2 μg/L for different predicted instream removal rates. 

 Method: Modeling was conducted to predict the 90th-percentile environmental 

concentration (PEC) of LAS and other detergent substances in aquatic 

environments in the Netherlands. Inputs included emissions data, prediction 

of raw sewage concentration and initial material characterization. Model 

predictions included the removal of LAS in wastewater treatment plants, 

concentrations in surface waters, and prediction of the 90th-percentile 

concentrations. 

 Remarks: The authors emphasize that to provide a fate assessment adequate for 

regulatory purposes, a need clearly exists for a fundamental interplay 

between monitoring, laboratory data, and these predictive models. This study 

is part of an extensive monitoring program executed jointly by the Dutch 

Soap Association (NVZ) and the Dutch Ministry of Housing, Spatial 

Planning and the Environment (VROM). Monitoring data from this program 

can be found in Matthijs et al. 1999. 

 Reference: Feijtel, T.C.J., Struijs, J., and Matthijs, E. 1999b. Exposure modeling of 

detergent surfactants – Prediction of 90th-percentile concentrations in the 

Netherlands. Environmental Toxicology and Chemistry 18:2645-2652. 

 Reliability: 2 Valid with restrictions 

 (d) 

 Results: The average concentration of LAS in the treated sewage of the sum 

wastewater treatment plants was 39 μg/L. The average total removal of LAS 

was 99.2%. 

 Method: Twenty four hour flow proportional samples of raw, settled, and treated 

sewage were collected by automatic samples during three consecutive days at 

seven sewage treatment plants in the Netherlands. All samples were 

collected between April and July 1994 and analyzed for traditional sewage 

treatment plant water quality parameters. Samples for the analysis of LAS 

and other surfactants were taken every 15 minutes (hourly composites) using 

a time proportional automatic sampler. The LAS in these samples was 

analyzed using an HPLC method with fluorescence detection. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 173

 Remarks: This study is part of an extensive monitoring program executed jointly by the 

Dutch Soap Association (NVZ) and the Dutch Ministry of Housing, Spatial 

Planning and the Environment (VROM). The authors indicate that field 

studies suggest that in-sewer removal can play a significant role in reducing 

the concentrations of surfactants entering the sewage treatment plant. 

 Reference: Matthijs, E., Holt, M.S., Kiewiet, A., and Rijs, G.B.J. 1999. Environmental 

monitoring for linear alkylbenzene sulfonate, alcohol ethoxylate, alcohol 

ethoxy sulfate, alcohol sulfate, and soap. Environmental Toxicology and 

Chemistry 18:2634-2644. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Methods: LAS was monitored seasonally for one year (winter, spring, summer) in a 

small river in Spain receiving untreated sewage from a non-industrial village 

(Caserras). Sampling was carried out during November 1994, May 1995 and 

July 1995. Grab samples were collected in the morning, afternoon and 

evening at five sampling sites representing the raw sewage discharge, a predischarge location on the river, and three downstream locations on the river 

(1.5, 3.0 and 4.8 km downstream of the discharge). 

 Results: Seasonal differences were observed in biodegradation, with total LAS 

removals (dissolved and adsorbed) at 4.8 km downstream of 31.8%, 95.5% 

and 98.3% for winter, spring and summer respectively. 

 Remarks: The seasonal differences in biodegradation are explained by hydraulic 

conditions. River flow rates are much greater in winter (75 m3

/min) versus 

spring (4.5 m3

/min) and summer (0.2 m3/min), which results in a much 

reduced hydraulic retention time (and thus less contact time for 

biodegradation) in winter of 1.6 hrs compared to 26.6 hrs in spring and 25 

days in summer. Overall, even in situations of direct discharge of untreated 

sewage, LAS biodegradation of >98% can be expected provided that the 

receiving water stream has adequate hydraulic conditions. 

 Reference: de Ferrer, J., Moreno, A., Vaquero, M.T. and Comellas, L. 1997. 

Monitoring of LAS in direct discharge situations. Tens. Surfactants Det. 

34:278-283. 

 Reliability: 2 Valid with restrictions 

 (f) 

 Results: LAS removal of 98-99% and biodegradation of 80-84% was observed. 

Sulfophenyl carboxylates (SPC) were found only in water and not the 

absorbed phases (sludge). 

 Remarks: This study was conducted to specifically study LAS biodegradation in real 

WWTP conditions in Italy. LAS data was obtained by HPLC of influent, 

effluent, dissolved waters and sludges to reach a complete mass balance. 

 Reference: 1) Cavalli, L., Gellera, A., Lazzarin, A., Nucci, G.C., Romano, P., Ranzani, 

M. and Lorenzi, E. 1991. Linear alkylbenzene sulphonate removal and 

biodegradation in a metropolitan plant for water treatment. Riv. Ital. 

Sostanze Grasse 68:75-81. 

 2) Cavalli, L., Gellera, A. and Landone, A. 1993. LAS removal and 

biodegradation in a wastewater treatment plant. Environmental Toxicology 

and Chemistry 12:1777-1788. 

 Reliability: 2 Valid with restrictions 

 

B. Other information

 (a) 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 174

 Remarks: A significant number of additional literature articles report data on the 

environmental fate of LAS. An additional bibliography of literature citations 

for LAS can be found in an Appendix to this dossier. 

 (b) 

 Type of Measurement: Background [X]; At contaminated site [ ]; Other [ ] 

 Medium: soil 

 Remarks: Where surfactant and hydrophobic organic compounds (HOCs) co-exist in 

soil-water systems there are a number of possible interactions which can 

occur simultaneously: 1) distribution of surfactant between monomeric, 

hemimicellar and miscellar forms, 2) competition for hydrophobic 

adsorption sites between the surfactant and HOC and 3) partitioning of 

HOC among soil hydrophobic adsorption sites, surfactant micelles and 

hemimicelles. The interaction of HOCs with surfactant monomers is 

usually very weak and insignificant. At concentrations where micelles and 

hemimicelles are present interactions can take place. Sorbed HOCs can be 

solubilised by free micelles, resulting in mobilisation. HOCs in solution 

are in equilibria between sorption onto hydrophobic adsorptive sites on the 

soil, partitioning into hemimicelles – both resulting in immobilisation, and 

partitioning into free micelles. Whether the HOCs are previously sorbed 

onto soil or are in solution, partitioning into micelles, hence mobilisation, is 

favoured by increasing surfactant concentration. A model has been put 

forward describing the effect of non-ionic surfactant on the distribution of 

HOC in a soil-water system. In simple terms the model illustrates that 

sorbed surfactant molecules tend to increase HOC sorption onto soil by 

increasing its fractional organic carbon content, and free surfactant tends to 

decrease sorption by increasing the apparent aqueous solubility of the 

HOC. 

 The biodegradation of HOCs in soil can be enhanced by surfactants due to 

enhanced solubility in the presence of micelles. In some cases however, 

biodegradation appears to be inhibited by micelles forming a barrier to the 

degrading organism. Any such inhibition is unlikely to be prolonged due to 

the biodegradable nature of most modern surfactants. In fact, it is very 

unlikely that micelles would be present in sludge-amended soils due to the 

low concentration of surfactants. 

 Although there is evidence that surfactants can effect the fate and behaviour 

of HOCs in soil, the potential for detergent ingredients to cause significant 

effects is limited due to the relatively low concentrations found compared 

with critical micelle concentrations (CMCs). In addition, the effective 

CMC in environments such as soil and sediments is generally much higher 

than in clean water systems. Typical soil concentrations of LAS, the most 

heavily used surfactant in domestic detergents, are significantly lower than 

those required to produce micelles in pore water. Therefore, it is unlikely 

that surfactants present in domestic detergents will contribute significantly 

to the mobilisation of HOCs in sludge-amended soil. 

 Reference: Haigh, S.D. 1996. A review of the interaction of surfactants with organic 

contaminants in soil. The Science of the Total Environment 185:161-170.
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4. ECOTOXICITY

4.1 ACUTE/PROLONGED TOXICITY TO FISH

(a) 

Type of Test: static [ ]; semi-static [ ]; flow-through [X] 

 Open-system [X]; closed-system [ ] 

Species: Lepomis macrochirus (Fish, fresh water) 

Exposure Period: 96 hours 

Results: LC50 = 1.67 mg/L 

Analytic Monitoring: Yes [X]; No [ ]; ? [ ] 

Method: USEPA (1975) Stock solutions were made up in deionized water without 

 the use of a solvent and metered into diluter chambers by peristaltic 

 pump. Mortality was analyzed by four methods: (a) the toxic unit 

 (TU) concept, (b) the additive index, (c) concentration addition, and 

 (d) response addition. 

GLP: Yes [ ]; No [X]; ? [ ] 

Test Substance: C11.8 LAS; Average molecular weight 345; 27.3% active; Alkyl chain 

Composition: C10 9.5%, C11 29.2%, C12 37.7%, C13 19.0%, C14 4.9% 

 Remarks: Average size of individual fish 1.1 g, mean standard length 4.2 cm; water 

 hardness 137 mg/L Ca CO3; temperature 20 ± 2°C; dissolved oxygen 

 8.4-9.6 mg/L; pH 7.3-8.1. Ten randomly selected fish were exposed to 

 each of the five concentrations and the control. A 16:8 (light:dark) 

 photoperiod was maintained. Fish were not fed during the study. 

 Mortality was recorded at 1, 3, and 5 hours after test initiation and then 

 daily until test termination. Samples were collected at the beginning and 

 end of the study and analyzed for the test substance. Results reported 

 are mean measured concentrations. The LC50 value reported represents 

the lowest value for this species. In addition to the studies conducted on 

LAS, the anionic LAS was also tested in binary and ternary equitoxic or 

equimolar mixtures with non-ionic C14-15 linear alkyl ethoxylate (AE) and 

cationic C12-14 MDAC. These mixture results are not reported in this robust 

summary. This is a key study for aquatic toxicity to fish (see SIAR Table 

10). 

 Reference: Lewis, M.A. and Perry, R.L. 1981. Acute toxicities of equimolar and 

 equitoxic surfactant mixtures to Daphnia magna and Lepomis 

 macrochirus. Aquatic Toxicology and Hazard Assessment: Fourth 

 Conference, ASTM STP 737, D.R. Branson and K.L. Dickson, Eds., 

 American Society for Testing and Materials, pp. 402-418. 

 Reliability: 2 Valid with restrictions. The studies are very well documented in this peerreviewed publication. 

(b) 

Species: Lepomis macrochirus and Pimephales promelas

Results: LC50 values ranged from 1.67 to 7.7 mg/L for L. macrochirus (10 records) 

 LC50 value for P. promelas = 4.1 mg/L (1 record) See study (q) below for 

 robust summary 

Test Substance: C10-13 LAS (CAS #68411-30-3) 

Remarks: A total of 18 fish studies for these two species were reviewed by HERA in 

2004. Seven of these studies were rejected because the test material was not 

commercial LAS, the study deviated significantly from standard protocols, or 

non-standard endpoints were measured. The remaining eleven studies were 

evaluated for reliability and the results reflect the range of acute LC50 values 

obtained for the most commonly tested fish species. These studies are 

tabulated and discussed further in the SIAR and SIAP in a weight-of-
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UNEP PUBLICATIONS 176

evidence approach. A robust summary for the study with the lowest LC50

value was prepared (see Lewis and Perry 1981 above). 

Reference: HERA-LAS team , May 2004; see SIAR, Annex 2. 

Reliability: 4 Not assignable. This study is given a reliability score of 4 because 

 it is a summary evaluation of a series of studies conducted by other 

 researchers. 

(c) 

Species: Lepomis macrochirus

 Results: LC50 = 3.0 mg/L (geometric mean of 88 records) 

 Test Substance: C10-14 LAS (all LAS in range, including data for individual homologues) 

 Remarks: Mean LC50 for bluegill sunfish was derived from a total of 88 records 

compiled from the BKH (1993) literature review. 

Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap, 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (d) 

 Species: Pimephales promelas

 Results: LC50 = 3.2 mg/L (geometric mean of 35 records) 

 Test Substance: C10-14 LAS (all LAS in range, including data for individual homologues) 

 Remarks: Mean LC50 for fathead minnow was derived from a total of 35 records 

compiled from the BKH (1993) literature review. The range of LC50 values 

(0.40-100 mg/L) is very large due to the range of materials tested (including 

many materials not representative of commercial LAS) and the differences in 

test design (not necessarily following standard guidelines). It is unclear 

which values within the range refer to the commercial LAS products and the 

individual records are not available for validation. 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap, 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (e) 

 Species: Leuciscus idus melanotus

 Results: LC50 = 2.9 mg/L (geometric mean of 11 records) 

 Test Substance: C10-14 LAS (all LAS in range, including data for individual homologues) 

 Remarks: Mean LC50 for golden orfe was derived from a total of 11 records compiled 

from the BKH (1993) literature review. 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap, 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

(f) 

 Species: Carassius auratus (goldfish) 
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UNEP PUBLICATIONS 177

 Oncorhynchus mykiss (rainbow trout) 

 Oryzias latipes (medaka) 

 Poecilia reticulata (guppy) 

 Results: LC50 (C. auratus) = 9.5 mg/L (46 records) 

 LC50 (O. mykiss) = 3.0 mg/L (10 records) 

 LC50 (O. latipes) = 13 mg/L (5 records) 

 LC50 (P. reticulata) = 3.8 mg/L (9 records) 

 Test Substance: C10-14 LAS (all LAS in range, including data for individual homologues) 

Remarks: Geometric mean LC50 values for the number of records listed for each 

species. The interspecies variation decreases considerably when the 

geometric mean value per species is calculated. 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap. 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

(g) 

 Species: Fish species (all marine) 

 Results: LC50 = 1.58 mg/L (6 records; SD = 0.16) 

 Test Substance: LAS; average alkyl chain length C11.7-12.0

 Remarks: LC50 is geometric mean of 6 records compiled from literature reviews. 

Geometric mean LC50 for all taxa (36 records; SD = 0.79) was 4.36 mg/L. 

 Reference: Temara, A., Carr, G., Webb, S., Versteeg, D., and Feijtel, T.C.J. 2001. 

Marine risk assessment: Linear alkylbenzensulphonates (LAS) in the North 

Sea. Mar. Poll. Bulletin 42:635-642. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (h) (Zebra fish)

 Type of test: static [ ]; semi-static [ ]; flow-through [ X ]; other[ ] 

 open-system [X]; closed-system [ ] 

 Species: Brachydanio rerio (Fish, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 5.1 mg/L 

 Analytical monitoring: Yes [ ] No [X ] ? [ ] 

 Method: OECD Guide-line 203 “Fish, Acute Toxicity Test” 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. The 

submitter (Huels AG) judged the study quality to be good. Water hardness: 

310 mg/L CaCO3; tap water diluent; 25 oC; adult fish tested. 

 Reference: European Commission. 2000f. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

AT/FU/80/90. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (i) 

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Brachydanio rerio (Fish, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 7.8 mg/L 
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 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: ISO 7346/1-3 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. 

Concentration of test substance related to MBAS. LC0 and LC100 = 5.6 and 

11 mg/L, respectively 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (j) 

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Brachydanio rerio (Fish, fresh water) 

 Exposure period: 14 day 

 Results: NOEC = 2 mg/L 

 LOEC = 8 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: OECD Guide-line 204 “Fish, Prolonged Toxicity Test: 14-day Study” 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. 

Concentration of test substance related to MBAS. 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (k) (Rainbow trout)

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Salmo gairdneri (Fish, estuary, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 5.8 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: OECD Guide-line 203 “Fish, Acute Toxicity Test” 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS (CAS # 68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. The 

submitter (Huels AG) judged the study quality to be good. Analysis showed 

92% of nominal concentration. Tap water diluent; water hardness = 96-120 

mg/L CaCO3; pH 6.8-7.3; daily renewal; 14.5-16oC; 5 month old fish tested. 

 Reference: European Commission. 2000i. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

AT/17. 

 Reliability: 4 Not assignable. The original study was not available for review. 

(l) 

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Salmo gairdneri (Fish, estuary, fresh water) 

 Exposure period: 96 hour 
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UNEP PUBLICATIONS 179

 Results: LC50 = 3 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: See remarks. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: DOBANIC ACID 102, C10-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Daily renewal of test solutions; 14-16 

oC; pH 7.6-8.4; water hardness = 210-240 mg/L CaCO3; DO=10.0-10.4 

 mg/L. Fingerlings were tested, mean weight 5.2 g 

 Reference: European Commission. 2000w. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Shell Research Ltd, 

SBGR.81.083, RR Stephenson. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (m) (Bluegill sunfish)

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Lepomis macrochirus (Fish, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 5.0 mg/L (mean of 8 tests) 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: EPA-660/3-75-009 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS, average chain length 11.8 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. LC50 values for the 8 tests conducted 

ranged from 3.7 to 7.7 mg/L. Nominal concentration, (expected deviation 

<20%), reconstituted water, water hardness = 30-48 mg/L CaCO3; pH 7.3-

7.8; 20-23oC; fish size: 0.35-0.89 g 

 Reference: European Commission. 2000q. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

22852, 23613, 23612, 23617, 23722, 22824, 28661, 27917. 

 Reliability: 4 Not assignable. The original studies were reviewed by HERA (2004) for 

Annex 2 and judged to be reliable. 

 (n) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Lepomis macrochirus (Fish, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 2.2 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: EPA-660/3-75-009 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS, average chain length 11.8 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Nominal concentrations, (expected 

deviation <20%). Reconstituted water with hardness = 44 mg/L CaCO3; pH 

7.58; 22oC; fish size: 0.35 g, 40 mm; Note that this study was not included in 

the HERA LAS acute toxicity data summary tables in the SIAR because only 

a summary of the study, not the full report, is available. 

 Reference: European Commission. 2000p. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

22581, 28361. 

 Reliability: 4 Not assignable. The original study was not available for review. 
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 (o) (Golden Orfe)

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Leuciscus idus (Fish, fresh water) (Golden orfe) 

 Exposure period: 48 hour 

 Results: LC50 = 4.6 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: Determination of the effect of substance in water on fish, DIN 38412 part 15 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. 

 Reference: European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Huels Study 

(unpublished). 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (p) (Fathead minnow)

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] not stated 

 Species: Pimephales promelas (Fish, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 4.6 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: Ten fathead minnows were exposed for 96 hours to LAS under the following 

conditions: hardness 35 mg/L as CaCO3; pH 7.1; temperature 21o

C. Fish 

were not fed during the exposure. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Low molecular weight LAS, sodium salt (CAS #68411-30-3); C10 5%, C11

27%, C12 53%, C13 13%, 2-phenyl 23%; average alkyl chain length = C11.1. 

 Remarks: The carboxylated intermediates formed in the biodegradation of LAS were 

also tested and found to be several orders of magnitude less toxic than LAS. 

These intermediates undergo further biodegradation, more rapidly in a natural 

river water than in a synthetic medium. 

 Reference: Swisher, R.D., Gledhill, W.E., Kimerle, R.A. and Taulli, T.A. 1978. 

 Carboxylated intermediates in the biodegradation of linear alkylbenzene 

 sulfonates (LAS). VII International Congress on Surface Active Substance, 

Proceedings, Moscow, 1976 4:218-230. 

 Reliability: 2 Valid with restrictions 

 

 (q)

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Pimephales promelas (Fish, fresh water) 

 Exposure period: 96 hour 

 Results: LC50 = 4.1 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: USEPA methods for acute toxicity tests with fish, macroinvertebrates, and 

amphibians. Ecol. Res. Series. EPA-660/3-75-009. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, average chain length 11.7 (CAS #68411-30-3) (C10 7.3%; C11

26.5%; C12 56.7%; C13 9.0%; C14 0.5%); Mean phenyl position = 3.9; Mean 

molecular weight = 345. 

 Remarks: Acute tests were conducted at EG&G Bionomics from 1971 to 1976 with 2-3 

month old fathead minnows in 20-L glass vessels with soft reconstituted 

water (hardness = 40 mg/L as CaCO3). Tests with LASs of average alkyl 
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UNEP PUBLICATIONS 181

chain length of 11.2 and 13.3 were conducted concurrently, with the resultant 

96 hour LC50 values of 12.3 and 0.86 mg/L, respectively. 

 Reference: Holman, W.F. and Macek, K.J. 1980. An aquatic safety assessment of linear 

alkylbenzene sulphonate (LAS); chronic effects on fathead minnows. Trans. 

Am. Fish. Soc. 109(1):122-131. 

 Reliability: 2 Valid with restrictions 

 (r) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Pimephales promelas (Fish, fresh water) 

 Exposure period: 48 hour 

 Results: The following table shows the acute toxicity of the tested materials (LC50, 

mg/L). 

 Fathead minnow LC50 (mg/L) 

Average chain length 24 hour 48 hour 

High molecular weight 

LAS

13.3 1.9 1.7 

Individual homologues 

LAS 

 

C10 10 48.0 43.0 

C11 11 17.0 16.0 

C12 12 4.7 4.7 

C13 13 1.7 0.4 

C14 14 0.6 0.4 

 

Nonlinear LAS

components (DTIS)

C10 10 87.0 ± 7.5 86.1 ± 15.0 

C12 12 24.8 ± 5.8 21.5 ± 5.5 

C14 14 8.1 ± 5.1 5.3 ± 3.9 

Model biodegradation

intermediates 

 

C4 (SØ Butyrate) 4 ~10,000 ~10,000 

C5 (SØ Valerate) 5 ~10,000 ~10,000 

C11 (SØU) 11 85.9 ± 5.1* 76.6 ± 12.4* 

*Subsequent repurification of this sample yielded a product with the same isomeric composition but 

with LC50 values over 1000 mg/L for fatheads. 

 Analytical monitoring: Yes [X] No [ ] ? [ ] MBAS 

 Method: EPA-660/3-75-009 1975. Method for acute toxicity tests with fish, 

macroinvertebrates and amphibians. 

 Acute toxicity tests were conducted on high molecular weight LAS, 

individual pure homologues, non-linear LAS components (dialkyl tetralin or 

indane sulfonates, DTIS), and model biodegradation intermediates 

(sulfophenylundecane, SOU) in order to determine whether biodegradation 

decreases toxicity. Toxicity tests were conducted in 5 L of 100 mg/L 

hardness water using 5 fathead minnows per concentration. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: 1) High molecular weight LAS: Average chain length = 13.3; C11 1%, C12

8%, C13 52%, C14 39% 

 2) Individual LAS homologues of C10, C11, C12, C13, and C14

 3) Nonlinear LAS components (DTIS) 

 4) Model biodegradation intermediates 
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UNEP PUBLICATIONS 182

 Remarks: The length of the alkyl chain is the most important factor influencing acute 

toxicity, which increases as the alkyl chain increases. These longer alkyl 

chain homologues are the first constituents of the LAS mixture to degrade. 

The nonlinear components (DTIS) showed 1/2 to 1/10 the toxicity of LAS 

with the same carbon chain length. Toxicity of biodegradation 

intermediates is significantly less than the parent LAS. Because of the 

shorter than normal study duration and smaller than standard number of 

fish per concentration, the reliability of the absolute values cannot be 

assessed. However, the study is considered reliable for the trends in the 

data because the homologues were tested under identical conditions. 

 Reference: Kimerle, R.A. and Swisher, R.D. 1977. Reduction of aquatic toxicity of 

linear alkylbenzene sulfonate (LAS) by biodegradation. Water Research 

11:31-37. 

 Reliability: 2 Valid with restrictions 

 

4.2 ACUTE TOXICITY TO AQUATIC INVERTEBRATES 

A. Daphnia 

 (a) 

 Type of Test: Static [X]; semi-static [ ]; flow-through 

 Open-system [X]; closed-system [ ] 

 Species: Daphnia magna (Crustacea) 

 Exposure Period: 48 hours 

 Effect Criteria: Immobility 

 Results: EC50 = 1.62 mg/L; The number of immobile animals at each concentration is 

shown in the following table: 

 

Concentration of test substance (mg/L) 

Time (h) 0 3.2 5.6 10 18 32 56 100 

0 0 0 0 0 0 0 0 0 

24 0 0 0 0 0 0 12 20 

48 0 0 0 1a

 6a 12a 20 20 a Condition of mobile animals was impacted as compared to the controls in a dose-responsive manner.

 

 Analytic Monitoring: Yes [X]; No [ ]; ? [ ] 

 Method: OECD Guideline 202. Seven concentrations (3.2, 5.6, 10, 18, 32, 56, and 

 100 mg/L) plus controls were tested. The dilution water was DSWL 

water, prepared from ground water. Four beakers containing five Daphnia 

each were used for each test or control solution. Daphnia were less than 24 

hours old at test initiation. A fifth beaker with 100 mg/L solution and five 

Daphnia were added 24 hours after initiation. Test and control solutions 

were not renewed and the Daphnia were not fed. Dissolved oxygen and pH 

were measured at 0 and 48 hours in all concentrations, as well as at 24 hours 

in the 100 mg/L chambers 24 hours after initiation because of total 

immobility observed at that level. Dissolved oxygen ranged from 8.7 to 9.6 

mg/L and pH ranged from 7.9 to 8.1. Water hardness was 215 mg/L as 

CaCO3. Test temperature was maintained at 20 ± 1°C under a 16:8 

(light:dark) cycle. The chambers were not aerated. Immobile animals were 

counted at 24 and 48 hours. Samples for analysis of each concentration were 

taken at 0, 24, and 48 hours. This is a key study for aquatic toxicity to 

invertebrates (see SIAR Table 10). 

 GLP: Yes [X]; No [ ]; ? [ ] 

 Test Substance: LAS; 87.85% activity 

 Remarks: A 24 hour EC50 of 3.58 mg/L and a 48 hour NOEC of 0.379 mg/L (both 
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UNEP PUBLICATIONS 183

 based on immobility) were also calculated, as well as a 48 hour NOEC 

of 5.6 mg/L based on condition. Only nominal concentrations are reported. 

No further information on the test substance is reported. 

 Reference: Hooftman, R.N. and van Drongelen-Sevenhuijsen, D. 1990. The acute 

 Toxicity of E-3473.01 (ETS 311) to Daphnia magna. TNO Netherlands 

 Organization for Applied Research. TNO Report No. R 89/403. 

 Reliability: 1 Valid without restrictions. 

 (b) 

 Species: Daphnia magna

 Results: EC50 values ranged from 1.62 to 9.3 mg/L 

 Test Substance: C10-13 LAS (CAS #68411-30-3) 

 Remarks: A total of 20 daphnid studies were reviewed by HERA in 2004. Nine of 

these studies were rejected because the test material was not commercial 

LAS, the study deviated significantly from standard protocols, or nonstandard endpoints were measured. The remaining 11 studies were evaluated 

for reliability and the results reflect the range of acute EC50 values obtained 

for Daphnia magna. These studies are tabulated and discussed further in the 

SIAR and SIAP in a weight-of-evidence approach. A robust summary for 

the study with the lowest acute EC50 value was prepared (see Hooftman and 

van Drongelen-Sevenhuijsen above). 

 Reference: HERA-LAS team, May 2004; see SIAR Annex 2. 

 Reliability: 4 Not assignable. This study has been given a reliability score of 4 because it 

is a summary evaluation of a series of studies conducted by other researchers. 

 (c) 

 Species: Daphnia magna

 Results: EC50 = 4.7 mg/L (139 records) 

 Test Substance: C10-14 LAS (all LAS in range, including data for individual homologues) 

 Remarks: EC50 is geometric mean of 139 records compiled from a BKH (1993) 

literature review. Values range from 0.26 to 55 mg/L. This large range is 

caused by differences in the LAS tested with respect to alkyl chain and/or 

phenyl isomer distribution and differences in test design. 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap, 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (d) 

 Type of test: static [ ]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [ ]; closed-system [ ] not stated 

 Species: Daphnia magna (Crustacea) 

 Exposure period: 48 hour 

 Results: EC50 = 6.8 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: Directive 84/449/EEC, C.2 “Acute toxicity for Daphnia” 1984 

 GLP: Yes [X] No [ ] ? [ ] 

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. 

 Reference: European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Huels Study 

(unpublished). 

 Reliability: 4 Not assignable. The original study was not available for review. 
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UNEP PUBLICATIONS 184

 

 (e) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [X]; closed-system [ ] 

 Species: Daphnia magna (Crustacea) 

 Exposure period: 48 hour 

 Results: LC50 = 5.5 mg/L (mean of 3 valid tests) 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: EPA-660/3-75-009 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: C10-13 LAS, average chain length 11.8 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Lifestage: <24 h. Effect: immobility. LC50 values for 4 tests ranged from 4.4 to 

10.4 mg/L. Huels AG judged study quality to be good. Nominal 

concentrations (expected deviation <20%). Reconstituted water with 

hardness = 162-220 mg/L CaCO3. Note that all four of these studies are 

included in Appendix 2, the HERA acute toxicity data review. Three of the 

studies, Reports 23618, 22853 and 23611 with respective values of 4.4, 4.9 

and 7.1 mg/L, are considered reliable and are included in the table of acute 

toxicity values. The fourth study, Report 23276 with a value of 10.4 mg/L, is 

listed among the rejected studies because it was conducted as part of a QA 

program to qualify various labs and the result is not considered reliable. 

 pH 7.86-8.53. 21-22oC 

 Reference: European Commission. 2000r. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

23618, 22853, 23611, 23276. 

 Reliability: 2 Valid with restrictions for the three valid studies. The original studies were 

reviewed by HERA (2004) for Annex 2. 

 

 (f) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [X]; closed-system [ ] 

 Species: Daphnia magna (Crustacea) 

 Exposure period: 48 hour 

 Results: The following table shows the acute toxicity of original materials (LC50, 

mg/L). 

 Daphnia magna 

Average chain length 24 hour 48 hour 

High molecular weight 

LAS

13.3 2.6 ± 0.1 2.3 ± 0.1 

Individual homologues 

LAS 

 

C10 10 53.1 ± 0.4 12.3 ± 2.6 

C11 11 15.8 ± 3.0 5.7 ± 0.6 

C12 12 10.7 ± 1.6 3.5 ± 1.0 

C13 13 2.7 ± 0.4 2.0 ± 0.3 

C14 14 1.2 ± 0.2 0.7 ± 0.2 

Nonlinear LAS

components (DTIS) 

 

C10 10 106.0 ± 27.0 98.0 ± 21.3 

C12 12 55.1 ± 9.1 34.1 ± 5.1 

C14 14 12.4 ± 1.4 10.0 ± 1.0 

Model biodegradation

intermediates 

 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 185

 Daphnia magna 

Average chain length 24 hour 48 hour 

C4 (SØ Butyrate) 4 ~12,000 ~6,000 

C5 (SØ Valerate) 5 ~12,000 ~5,000 

C11 (SØU) 11 355 ± 150* 208 ± 85* 

*Subsequent repurification of this sample yielded a product with the same isomeric composition but 

with LC50 values over 1000 mg/L for daphnids (Swisher et al., 1976). 

 Analytical monitoring: Yes [X] No [ ] ? [ ] MBAS

 Method: EPA-660/3-75-009 1975. Method for acute toxicity tests with fish, 

macroinvertebrates and amphibians. 

 Acute toxicity tests were conducted on high molecular weight LAS, 

individual pure homologues, non-linear LAS components (dialkyl tetralin or 

indane sulfonates (DTIS), and model biodegradation intermediates 

(sulfophenyl undecane, SØU) in order to determine whether biodegradation 

decreases toxicity. In 250 mL beakers with 200 mL of well water of 

approximately 250 mg/L hardness, ten Daphnia, less than 18 hours old, were 

placed in each of the three beakers. No food was added for the duration of 

the test. 

 GLP: Yes [X] No [ ] ? [ ] 

 Test substance: 1) High molecular weight LAS: Average chain length = 13.3; C11 1%, C12

8%, C13 52%, C14 39% 

 2) Individual LAS homologues of C10, C11, C12, C13, and C14

 3) Nonlinear LAS components (DTIS) 

 4) Model biodegradation intermediates 

 Remarks: The length of the alkyl chain is the most important factor influencing acute 

toxicity, which increases as the alkyl chain increases. These longer alkyl 

chain homologues are the first constituents of the LAS mixture to degrade. 

The nonlinear components (DTIS) showed 1/2 to 1/10 the toxicity of LAS 

with the same carbon chain length. Toxicity of biodegradation 

intermediates is significantly less than the parent LAS. Daphnia acute 

toxicity tests on partially degraded LAS demonstrated that toxicity is 

significantly lessened as LAS biodegraded. Because of the shorter than 

normal study duration and smaller than standard number of Daphnia per 

concentration, the reliability of the absolute values cannot be assessed. 

However, the study is considered reliable for the trends in the data because 

the homologues were tested under identical conditions. 

 Reference: Kimerle, R.A. and Swisher, R.D. 1977. Reduction of aquatic toxicity of 

linear alkylbenzene sulfonate (LAS) by biodegradation. Water Research 

11:31-37. 

 Reliability: 2 Valid with restrictions 

B. Other aquatic invertebrates 

 (a) 

 Species: Gammarus pulex (amphipod) 

 Mysidopis bahia (mysid) 

Panaeus duorarum (pink shrimp) 

 Results: EC50 (G. pulex) = 6.2 mg/L (25 records) 

 EC50 (M. bahia) = 1.7 mg/L (6 records) 

 EC50 (P. duorarum) = 49 mg/L (5 records) 

 Test Substance: C10-14 LAS (all LAS in range, including data for individual homologues) 

 Remarks: Geometric mean EC50 values for number of records listed for each species. 

The interspecies variation decreases considerably when the geometric mean 

value per species is calculated. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 186

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap, 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (b) 

 Species: Crustacean species 

 Results: LC50 = 17.0 mg/L (14 records; SD = 0.68) 

 Test Substance: LAS; all in the alkyl chain length C10-14

 Remarks: LC50 is geometric mean of 14 records compiled from literature reviews. 

Geometric mean LC50 for all taxa (36 records) was 4.36 mg/L. 

 Reference: Temara, A., Carr, G., Webb, S., Versteeg, D., and Feijtel, T.C.J. 2001. 

Marine risk assessment: Linear alkylbenzensulphonates (LAS) in the North 

Sea. Mar. Poll. Bulletin 42:635-642. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (c) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [X]; closed-system [ ] 

 Species: Chironomus riparius (chironomid) 

 Exposure period: 96 hour 

 Results: LC50 = 6.5 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: EPA 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: C10-13 LAS, average chain length 12.3 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Nominal concentrations (expected 

deviation <20%). Well water with hardness = 24-30 mg/L CaCO3; pH 7.1; 

21-22oC 

 Reference: European Commission. 2000v. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

34845. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (d) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [X]; closed-system [ ] 

 Species: Limnodrilus hoffmeisteri (aquatic worm) 

 Exposure period: 96 hour 

 Results: LC50 = 1.8 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: EPA 660/3-75-009 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: C10-13 LAS, average chain length 12.3 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. 

Additional LC50 values for extended exposure times: 144 h: 1.1 mg/L, 196 h: 

0.96 mg/L. Huels AG judged study quality to be good. Nominal 

concentrations (expected deviation <20%). Well water with hardness = 24-

30 mg/L CaCO3; pH 7.1; 21-22oC. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 187

 Reference: European Commission. 2000v. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

34845. 

 Reliability: 4 Not assignable. The original study was not available for review. 

(e) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [ ]; closed-system [ ] 

 Species: Planaria sp. (aquatic worm) 

 Exposure period: 48 hour 

 Results: LC50 = 1.8 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: EPA 660/3-75-009 

 GLP: Yes [ ] No [ ] ? [ X] 

 Test substance: C10-13 LAS, average chain length 12 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Nominal concentrations (expected 

deviation <20%). Reconstituted water with hardness 165 mg/L CaCo3. pH 

8.1–8.4; 21-22o

C; size 3.4 cm. 

 Reference: European Commission. 2000u. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

31340. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (f) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ]; 

 open-system [X]; closed-system [ ] 

 Species: Rhabditis sp. (nematode) 

 Exposure period: 48 hour 

 Results: LC50 = 16 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: EPA 660/3-75-009 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: C12 LAS (CAS #25155-30-0) (average chain length 11.8) 

 Remarks: Nominal concentrations, (expected <20%), 3 replicates of 5 test 

concentrations plus a control. Reconstituted water with hardness = 65 mg/L 

CaCO3; DO 5.3 mg/L; pH 8.1-8.4; 21-23oC; size: 0.3 mm; 12 hr. 

 photoperiod at 40-70 L/ft 2

. Five other species were also tested and had the 

following 48-hr LC50 values (all mg/L): Midge 23; Gammarus (amphipod) 

3.3; Asellus (isopod) 270; Dugesia (flatworm) 1.8; and Dero (oligochaete) 

1.7. 

 Reference: Lewis, M.A. and Surprenant, D. 1983. Comparative acute toxicities of 

surfactants to aquatic invertebrates. Ecotoxicol. Env. Saf. 7(3):313-322. 

 Reliability: 2 Valid with restrictions 

4.3 TOXICITY TO AQUATIC PLANTS, e.g. algae 

(a) 

Type of Test: Static [X]; semi-static [ ]; flow-through [ ] 

 Open-system [X]; closed-system [ ]; not stated [ ] 

Species: Selenastrum capricornutum (algae) 

 Endpoint: Biomass [ ]; Growth rate [X ]; Other [ ]

Exposure Period: 96 hours 

Results: EC50 = 29.0 mg/L 

 NOEC = 0.5 mg/L 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 188

 LOEC = 1.0 mg/L 

Analytic Monitoring: Yes [ ]; No [ ]; ? [X] 

Method: ASTM. 1984. Standard Practice for Conducting Toxicity Tests with 

 Microalgae, Draft #7, Philadelphia, PA. Algae were exposed to the test 

material for four days, after which cell counts were made. The EC50 value 

was calculated using the method of Larson and Schaefer. Assumed 1 x 104

cells/mL because ASTM protocol, but not reported. 

GLP: Yes [ ]; No [X]; ? [ ] 

Test Substance: C11.8 LAS; MW = 345; technical grade LAS from P&G 

Remarks: The first significant effect concentrations were 

between 0.5 and 1.0 mg/L. Mean test temperature was 23.6 (21.2-25.6 °C). 

Total mean water hardness was 137 mg/L as CaCO3. The pH range was 6.8 

to 7.2. Mean dissolved oxygen was 9.1 mg/L. Results of the laboratory 

studies were compared with enclosure studies conducted with natural 

phytoplankton assemblages. Concentrations in the enclosures that first 

altered community structure were found to be between 27 and 108 mg/L. 

The EC50 value reported represents the lowest acute value for algal species 

for which a report or publication was available. This is a key study for 

aquatic toxicity to algae (see SIAR Tables 10 and 12). 

Reference: 1) Lewis, M.A. 1986. Comparison of effects of surfactants on freshwater 

phytoplankton communities in experimental enclosures and on algal 

population growth in the laboratory. Environ. Toxicol. Chem. 5:319-332. 

 2) Lewis, M.A. and Hamm, B.G. 1986. Environmental modification of the 

photosynthetic response of lake plankton to surfactants and significance to a 

laboratory-field comparison. Wat. Res. 20:1575-1582. 

Reliability: 2 Valid with restrictions 

(b) 

Species: Selenastrum capricornutum and Scenedesmus subspicatus

 Endpoint: Biomass [ ]; Growth rate [X ]; Other [ ]

Results: ErC50 values ranged from 29 to 35.5 for S. capricornutum (two records) 

ErC50 values ranged from 82 to 163 mg/L for S. subspicatus (three records) 

Test Substance: C10-13 LAS (CAS #68411-30-3) 

Remarks: A total of 13 algae studies originally were reviewed by HERA in 2004. Eight 

of these studies were rejected because 

 the test material was not commercial LAS, the study deviated 

 significantly from standard protocols, or non-standard endpoints were 

 measured. The remaining five studies were evaluated for reliability and 

 the results reflect the range of acute ErC50 values obtained for the two 

 most commonly tested algal species. These studies are tabulated and 

 discussed further in the SIAR and SIAP in a weight-of-evidence 

 approach. A robust summary for the study with the lowest acute ErC50

 value was prepared (see Lewis 1986 above). 

Reference: HERA-LAS team, May 2004; see SIAR Annex 2. 

Reliability: 4 Not assignable. This study is given a reliability score of 4 because it is 

 a summary evaluation of a series of studies conducted by other 

researchers. 

(c) 

Species: Chlamydomonas reinhardi, Chlorella kessleri, Microcystis sp., Plectonema 

boryanum, Scendesmus subspicatus, Selenastrum sp. (algae) 

Results: NOEC (C. reinhardi) = 12 mg/L (1 record) 

 NOEC (C. kessleri) = 3.5 mg/L (1 record) 

 NOEC (Microcystis sp.) = 0.80 mg/L (4 records) 

 NOEC (P. boryanum) = 15 mg/L (1 record) 

 NOEC (S. subspicatus) = 7.7 mg/L (4 records) 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 189

 NOEC (Selenastrum sp.) = 3.8 mg/L (9 records) 

Test Substance: LAS normalized to C11.6

Remarks: Geometric mean NOEC values for number of records listed for each species. 

Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap. 

Environ. Toxicol. Chem. 18:2653-2663. 

Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

(d) (Scenedesmus)

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X ]; Other [ ]

 Exposure period: 72 hour 

 Results: The 72-hr EC50 values were 240, 163, and 54.3 mg/L for the C11, C11.6, and 

C13 LAS, respectively. Other endpoints not determined. 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: OECD 201 Algal growth inhibition test. 1984. The test media recommended 

by AFNOR was used. All water quality parameters were maintained within 

acceptable ranges in compliance with the test protocol. Initial cell 

concentrations were 1 x 104

 cells/mL. Final cell counts not reported. 

 open-system [X]; closed-system [ ] 

 GLP: Yes [X] No [ ] ? [ ] 

 Test substance: Three different alkyl chain lengths of LAS (C11, C11.6, C13), with the 

following homologue distributions: 

 

 Alkyl Chain Length Distributions (%) 

 LAS C11 LAS C11.6 LAS C13

<C10 1.5 0.4 -- 

C10 29.0 8.9 1.0 

C11 39.0 33.7 3.5 

C12 28.5 31.0 17.8 

C13 1.8 24.0 37.0 

C14 0.2 2.0 40.4 

>C14 -- -- 0.3 

LAS MW 

(as Na-LAS) 334 343 363 

 Remarks: German strain of S. subspicatus from the University of Gottingen. Other 

endpoints were not reported. 

 Reference: Verge, C. and Moreno, A. 1996a. Toxicity of anionic surfactants to 

green microalgae “Scenedesmus subspicatus” and “Selenastrum capricornutum.” Tenside 

Surf. Det. 33:166-168. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X ]; Other [ ]

 Exposure period: 72 hour 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 190

 Results: The 72-hr EC50 values were 270, 111, 48, 30, and 18 mg/L for pure 

homologues C10, C11, C12, C13, and C14, respectively. The corresponding 

NOEC values were 80, 40, 18, 12, and 7, respectively. 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: OECD 201 Algal growth inhibition test. 1984. The test media recommended 

by AFNOR was used. All water quality parameters were maintained within 

acceptable ranges in compliance with the test protocol. Initial cell 

concentrations were 1 x 104

 cells/mL. Final cell counts not reported. 

 open-system [X]; closed-system [ ] 

 GLP: Yes [X] No [ ] ? [ ] 

 Test substance: Five pure homologue cuts were tested, with the following distribution. 

 Alkyl Chain Length Distributions (%) 

 LAS C10 LAS C11 LAS C12 LAS C13 LAS C14

<C10 0.5 -- 0.4 -- -- 

C10 96.8 5.5 13.9 0.7 -- 

C11 2.7 93.7 84.5 9.8 0.6 

C12 -- 0.8 1.2 78.3 1.0 

C13 -- -- -- 11.2 15.4 

C14 -- -- -- -- 82.1 

>C14 -- -- -- -- 0.9 

LAS MW 

(as Na-LAS) 320.7 333.7 346.4 362.3 373.7 

 Remarks: French strain of S. subspicatus from the University of Metz. As NOEC (no 

observed effect concentration), the authors used the EC5 because of the lack 

of noticeable variation in toxicity for the interval 0-5%. This is a key study 

for aquatic toxicity to algae (see SIAR Table 12). 

 Reference: Verge, C. and Moreno, A. 1996a. Toxicity of anionic surfactants to 

green microalgae “Scenedesmus subspicatus” and “Selenastrum capricornutum.” Tenside 

Surf. Det. 33:166-168. 

 Reliability: 2 Valid with restrictions 

 (f) 

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [X]; Growth rate [X]; Other [ ]

 Exposure period: 72 hour 

 Results: ErC50 (growth rate) = 127.9 mg/L; EbC50 (biomass) = 43.2 mg/L 

 NOEC (growth rate) = 2.4 mg/L; NOEC (biomass) = 2.2 mg/L 

 LOEC (growth rate) = 10 mg/L 

Inhibition of cell growth by concentration and duration is shown in the table 

below: 

Cell number ( x 104

 cells/mL) 

Time Period (hours) 

Test concentration 

(mg/L) 0 24 48 72 

Control 2 8 29 95 

0.6 2 8 30 89 

2.4 2 9 28 85 

10 2 9 27 75 

40 2 8 20 48 

160 2 7 9 8 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 191

Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: open-system [X]; closed-system [ ] 

 Algal growth inhibition test (88/302/EWG) 1988. 

Nominal test concentrations were control, 0.6, 2.4, 10, 40, and 160 mg/L. 

Algae were exposed to LAS in Erlenmeyer flasks in an environmental 

chamber on a light table at 8000 lux. Cell numbers were photometrically 

determined (8 subsets were taken for each concentration). 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6; 91.3% activity 

 Remarks: Initial cell concentrations were 20,000 cells/mL. Cell concentrations at 72 h 

were 95, 89, 85, 75, 48 and 8 (all x 104

/mL) for the control, 0.6, 2.4, 10, 40 

and 160 mg/L LAS concentrations, respectively. The pH ranged from 7.7 to 

7.9 at the beginning of the study and 7.9 to 9.0 at the end of the study. Test 

temperature was maintained at 24 ± 2 °C. This is a key study for aquatic 

toxicity to algae (see SIAR Table 12). 

 Reference: Scholz, N. 1992. Bestimmung der Auswirkungen von Marlon A 390 auf das 

Wachstum von Scenedesmus subspicatus 86.81. SAG 

(Algenwachstumshemmtest nach Richtlinie 88/302/EWG) Huels Final 

Report No. AW-291. 

 Reliability: 1 Valid without restriction 

 

 (g) 

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [X]; Growth rate [X]; Other [ ]

 Exposure period: 72 hour 

 Results: ErC50 (growth rate) = 82 mg/L; EbC50 (biomass) = 20 mg/L 

 NOEC (growth rate) = 0.4 mg/L; NOEC (biomass) = 0.1 mg/L 

Inhibition of cell growth by concentration and duration is shown in the table 

below: 

Cell number ( x 104

 cells/mL) 

Time Period (hours) 

Test concentration 

(mg/L) 0 24 48 72 

Control 2 9 32 94 

0.1 2 9 32 91 

0.4 2 9 29 88 

1.6 2 9 28 76 

6.4 2 9 24 60 

25 2 9 21 54 

160 2 6 7 7 

Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: open-system [X]; closed-system [ ] 

 Algal growth inhibition test (92/69/EWG) 

Nominal test concentrations were control, 0.1, 0.4, 1.6, 6.4, 25 and 160 mg/L. 

Test concentrations were measured at 0 and 72 h and found to confirm the 

nominal concentrations. Algae were exposed to LAS in Erlenmeyer flasks in 

an environmental chamber on a light table at 8000 lux. Cell numbers were 

photometrically determined (8 subsets were taken for each concentration). 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6; 52.1% activity 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 192

 Remarks: Initial cell concentrations were 20,000 cells/mL. Cell concentrations at 72 h 

94, 91, 88, 76, 60, 54 and 7 (all x 104

/mL) for the control, 0.1, 0.4, 1.6, 6.4, 

25 and 160 mg/L LAS concentrations, respectively. The pH ranged from 8.2 

to 8.3 at the beginning of the study and 8.0 to 9.4 at the end of the study. Test 

temperature was maintained at 24 ± 2 °C. This is a key study for aquatic 

toxicity to algae (see SIAR Table 12). 

 Reference: Scholz, N. 1994. Bestimmung der Auswirkungen von Marlon A 350 auf das 

Wachstum von Scenedesmus subspicatus 86.81. SAG 

(Algenwachstumshemmtest nach Richtlinie 92/69/EWG) Huels Final 

Report No. AW-372. 

 Reliability: 1 Valid without restriction 

 (h) 

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [X]; Growth rate [ ]; Other [ ]

 Exposure period: 96 hour 

 Results: EC50 = 5 mg/L 

Analytical monitoring: Yes [ ] No [ ] ? [X]

 Method: DIN 38412 Part 9 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Data refer 

to 100% active ingredient. Test method conforms with OECD-Guideline 

201. 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (i) 

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X]; Other [ ]

 Exposure period: 96 hour 

 Results: EC50 = 9 mg/L 

Analytical monitoring: Yes [ ] No [ ] ? [X]

 Method: Directive 87/302/EEC, part C, p. 89 “Algal inhibition test” 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt; average chain length 11.6 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. 

 Reference: European Commission. 2000c. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Huels AG, 1/90, N. 

Scholz, unpublished. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (j) 

 Species: Scenedesmus subspicatus (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X]; Other [ ]

 Exposure period: 96 hour 

 Results: EC50 = 30 mg/L 

Analytical monitoring: Yes [X ] No [ ] ? [ ]

 Method: ISO 8692 “Water quality - Fresh water algal growth inhibition test with 

Scenedesmus subspicatus and Selenastrum capricornutum” 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C11-13 LAS 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 193

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Nominal concentrations (deviation 

<3%); BBM medium; pH 6.4-6.7; 20-22oC. Note that although this was cited 

in IUCLID as a Procter & Gamble report, Procter & Gamble indicates that it 

is unlikely that it is one of their reports. 

 Reference: European Commission. 2000h. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

AL/12. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (k) (Selenastrum)

 Species: Selenastrum capricornutum (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X]; Other [ ]

 Exposure period: 96 hour 

 Results: EC50 = 4.29-12.5 mg/L 

Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: OECD Guideline 201 “Algae, Growth Inhibition Test”, 1984 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS, average chain length 11.8 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Water hardness = 150 mg/L as 

NaHCO3. Reported results are EC50 values for 2 tests. Static mean EC50 = 

7.3 mg/L. 

 Reference: European Commission. 2000t. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

29101. 

 Reliability: 3 Invalid. Based on correspondence with Procter & Gamble, it appears 

 that this study was mis-cited. The P&G report 29101 indicates 96-h 

 EC50 values of 29 mg/L and greater than 10 mg/l, not the values 

 reported above. In addition, the P&G study was not conducted under 

 the OECD Guideline cited. Given these discrepancies, the values are 

 uncertain and are considered invalid. 

 

 (l) 

 Species: Selenastrum capricornutum (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X]; Other [ ]

 Exposure period: 72 hour 

 Results: EC50 = 11 mg/L 

Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: ISO 8692 “Water quality - Fresh water algal growth inhibition test with 

Scenedesmus subspicatus and Selenastrum capricornutum” 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C11-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Nominal concentrations (deviation 

<13%); BBM medium; pH 6.5-6.6; static. Note that although this was cited in 

IUCLID as a Procter & Gamble report, Procter & Gamble indicates that it is 

unlikely that it is one of their reports. 

 Reference: European Commission. 2000g. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

AL/10. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (m) 

 Species: Selenastrum capricornutum (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X]; Other [ ]
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UNEP PUBLICATIONS 194

 Exposure period: 96 hour 

 Results: EC50 = 12.2 mg/L 

Analytical monitoring: Yes [ ] No [ ] ? [X]

 Method: EPA, l987. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS, average chain length 12.3 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. AAP medium; 24+

/-2oC. 

 Reference: European Commission. 2000n. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

P2636.01. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (n) 

 Species: Selenastrum capricornutum (Algae) 

 Endpoint: Biomass [ ]; Growth rate [X]; Other [ ]

 Exposure period: 48 hour 

 Results: EC50 ≈ 80 mg/L (Observation of graphical plot in paper indicates that the 

EC50 is between 50-100 mg/L) 

Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: Algal Assay Procedure Bottle Test, USEPA (1971). 

 Individual test flasks were spiked with a 1 mL algal suspension at 0.7 

 mg/L dry weight for each concentration. Test solutions were run in 

 triplicate. Algae were maintained at 24 ± 2°Cat 4000 lux for 48 hours. 

 Cell counts were accomplished with a Coulter Counter and the growth 

 Rate calculated. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C11.6 LAS; 23.4% activity 

 Remarks: Though generally valid, this study was not included in the HERA assessment 

because the exposure period was only 48 hours. 

 Reference: Yamane, A., Okada, M. and Sudo, R. 1984. The growth inhibition of 

planktonic algae due to surfactants used in washing agents. Water Res. 

9:1101-1105. 

 Reliability: 2 Valid with restrictions. Duration of test considered too short for a chronic 

study, therefore not included in SIAR Table 12A. 

 (o) (Elodea)

 Species: Elodea canadensis (aquatic plant) 

 Endpoint: Biomass [ ]; Growth rate [ ]; Other [X] inhibition of growth, productivity 

 Exposure period: 28 day 

 Results: NOEC > 4 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: The effect of LAS on the structure and function of microbial communities 

was studied in a flow-through model ecosystem containing several trophic 

levels. Duplicate 19-L glass aquaria containing model ecosystems at four 

nominal concentrations (0.5, 1.0, 2.0, 4.0 mg/L) contained water and 2.5 cm 

lake sediment (Winton Lake, Cincinnati, OH) and several trophic levels 

(bacteria, algae, macrophytes [Elodea canadensis,Lemna minor], 

macroinvertebrates [Daphnia magna, Paratanytarsus parthenogenica], and 

fish [Lepomis macrochirus]). Flow rate in the proportional diluter delivered 

approximately 8 replacement volumes per day. Additionally, at each cycle of 

the diluter, 1.5 mL of a Daphnia food suspension diluted with a culture of 

Selenastrum was added to each chamber. Following an initial 3 day 

acclimation period to analytically confirm test concentrations, 4 glass 

periphyton slides (5 x 5 cm), 8 vegetative shoots of Elodea, 10 early instar 

Daphnia, 25 midge eggs and 5 pre-weighed juvenile bluegills (2.5-5.0 cm 
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length) were added to each aquarium. Fish were screened from access to the 

macroinvertebrates by a 60 mesh stainless steel screen and were fed a daily 

supplement of frozen brine shrimp. Test duration was 28 days. Effects 

monitored included population and community effects. Nominal 

concentrations were confirmed with MBAS analysis. After 28 days the 

vegetative shoots of Elodea were removed, the total length measured, and the 

shoots were placed into aluminium dishes for determination of ash-free dry 

weights. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS; C14-LAS chain length C12 (91% purity) plus unlabeled LAS with 

average chain length C11.6 (C10 9.7%, C11 27.9%, C12 54.4%, C13 8.0%; 95% 

purity) (tested together) 

 Remarks: Dissolved oxygen concentrations ranged between 7.0 and 9.0 mg/L. 

Temperature was maintained at 2°C and the mean pH was 8.1 ± 0.2. The 

growth and productivity of Elodea was not significantly inhibited at the 

highest concentration tested (4 mg/L) in Phase I. Growth throughout the 28-

day exposure approximately doubled the initial biomass of the vegetative 

shoots from a mean of about 37 mg ash-free dry weight to a mean of about 

72 mg for the treatment concentrations. Similarly, Phase II experiments 

resulted in an approximate doubling of the initial Elodea biomass in the 

controls and the 3.75% effluent concentration, though the heavy growth of 

attached bacteria and fungi (periphyton) that developed in the higher 

concentrations effectively covered the growing surface of the Elodea shoots 

resulting in progressively lower productivity in 7.5, 15 and 30% dilutions. 

 Reference: Maki, A.W. 1981. A Laboratory model ecosystem approach to 

environmental fate and effects studies. Unpublished Internal Report, 

Environmental Safety Department Procter and Gamble Company, 

Cincinnati, Ohio. 

 Reliability: 2 Valid with restrictions 

 

(p) (Lemna) 

 Species: Lemna minor (aquatic plant) 

 Endpoint: Biomass [ ]; Growth rate [ ]; Other [X] frond count 

 Exposure period: 7 days 

 Results: EC50 = 2.7 mg/L 

 NOEC = 0.9 mg/L (calculated as EC50/3); normalized to C11.6 = 1.1 mg/L 

Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: A 7-day flow-through growth inhibition test was developed using duckweed 

(Lemna minor). Control water (carbon and reverse osmosis filtered well 

water) and five concentrations of test material were delivered from diluter 

mixing chambers to Pyrex glass exposure chambers at a rate of 1.5 L every 

16 minutes (approximately 14 replacement volumes per day). At time 0, 

each chamber received seven 2-frond, root excised duckweed colonies (four 

replicates per treatment level). Plants were given continuous illumination at 

3875 lux (360 foot candles) and temperature was maintained between 21 and 

23o

C. Total hardness was 120-130 mg/L CaCO3 and pH was 7.2-7.6. The 

number of fronds was recorded once every 24 hours for 7 days. LAS 

concentrations were measured using the MBAS method. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-14 LAS, average alkyl chain length 11.8, MW = 345, 27.3% active 

 Remarks: Results based on frond count were found to provide the most useful 

information per unit of laboratory time. Other endpoints resulted in 7-day 

EC50 values of 3.6 mg/L (dry weight), 4.9 mg/L (root length), and 4.8 mg/L 

(growth rate/doubling time). Concurrent tests with bluegill sunfish (96-hr 

LC50 = 1.7 mg/L) and D. magna (48-hr LC50 = 4.4 mg/L) indicate that 
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UNEP PUBLICATIONS 196

protection criteria developed for these species should be adequate to protect 

the aquatic macrophyte community without the need for additional testing. 

 Reference: Bishop, W.E. and Perry, R.L. 1981. Development and Evaluation of a FlowThrough Growth Inhibition Test with Duckweed (Lemna minor). Aquatic 

....... Toxicology and Hazard Assessment. ASTM STP 737. Branson, D.R. 

 and Dickson, K.L. (ed.). 

 Reliability: 2 Valid with restrictions 

 (q) 

Type of Test: Static [X]; semi-static [ ]; flow-through [ ] 

 Open-system [ ]; closed-system [ ]; not stated [X] 

Species: Chlamydomonas reinhardi (algae) 

Exposure Period: not stated 

Effect Criteria: Growth inhibition 

Results: NOEC = 15 mg/L 

 LOEC = 20 mg/L 

Analytic Monitoring: Yes [ ]; No [ ]; ? [X] 

Method: LAS concentrations of 1, 5, 10, 15, 20 and 30 mg/L were prepared in 

 Deionized, sterilized double-distilled glass water. Algae were grown 

 in Bold’s medium. Cell counts were made using a spectrophotometer and 

 dry weight observations. 

GLP: Yes [ ]; No [X]; ? [ ] 

Test Substance: C11.2 LAS 

Remarks: No morphological changes were observed. The growth rate was reduced at 

LAS concentrations of 20 mg/L. Protein analysis indicated that higher 

concentrations did affect protein synthesis. The NOEC normalized by van de 

Plassche et al. (1999) to C11.6 LAS was 12 mg/L. 

Reference: Dhaliwal, A.A., Campione, A., and Smaga, S. 1977. Effect of linear 

alkylbenzene sulfonate (C11.2 LAS) on the morphology and physiology of 

Plectonema boryanum and Chlamydomonas reinhardi. J. Phycol. 13:18. 

 Reliability: 4 Not assignable. This study was given a reliability score of 4 because the 

document reviewed was an abstract. 

 (r) 

Type of Test: Static [X]; semi-static [ ]; flow-through [ ] 

 Open-system [ ]; closed-system [ ]; not stated [X] 

Species: Chlorella kessleri (algae) 

Exposure Period: 15 days 

Effect Criteria: Growth rate 

Results: NOEC = 3.1 mg/L 

 LOEC = 10 mg/L 

Analytic Monitoring: Yes [ ]; No [X]; ? [ ] 

Method: EPA-600/9-78-018. Algal Assay Bottle Test. Determination of the 

 Inhibitory effect of water constituents on green algae, by William E. 

 Joseph C. Greene, and Tamotsu Shiroyama, Cornwallis Environmental 

 Research Laboratory, Corvallis, Oregon. 

GLP: Yes [ ]; No [X]; ? [ ] 

Test Substance: Marlon A 350, Benzenesulfonic acid, C10-13-alkyl derives., sodium salts 

 (CAS #68411-30-3); 25.7% activity. 

Remarks: No morphological changes were observed. The growth rate was reduced at 

LAS concentrations of 20 mg/L. Protein analysis indicated that higher 

concentrations did affect protein synthesis. The NOEC normalized by van de 

Plassche et al. (1999) to C11.6 LAS was 3.5 mg/L. 

Reference: Henkel KGaA, Biological Research and Product Safety/Ecology, 

unpublished results of study conducted in 1984; test substance Fi 5829. 
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UNEP PUBLICATIONS 197

 Reliability: 2 Valid with restrictions. Non-standard length of study, therefore not 

included in SIAR Table 12A. 

 (s) 

Type of Test: Static [X]; semi-static [ ]; flow-through [ ] 

 Open-system [X]; closed-system [ ]; not stated [ ] 

Species: Microcystis aeruginosa (algae) 

Exposure Period: 96 hours 

Effect Criteria: Growth rate 

Results: EC50 = 0.9 mg/L 

Analytic Monitoring: Yes [ ]; No [X]; ? [ ] 

Method: The test species was cultured following the procedures of USEPA 1971. 

 Temperature was maintained at 24 ± 2°C. Water chemistry was 

 determined at least once during each test according to Standard 

Methods (APHA 1985). EC50 values were calculated using the method of 

Larson and Schaeffer (1982) or graphical interpolation. 

GLP: Yes [ ]; No [X]; ? [ ] 

Test Substance: C12 LAS; average molecular weight = 345 

Remarks: Mean hardness was 137 mg/L as CaCO3, pH range was 6.8-7.2, and the mean 

dissolved oxygen was 9.1 mg/L. Comparison was also made to in situ

studies conducted in which lake water was bottled and suspended in Lake 

Acton (Ohio) for 3 hour periods. The mean 3-h EC50 (photosynthesis) for the 

in situ studies was 3.4 mg/L (0.5-8.0 mg/L). The NOEC normalized by van 

de Plassche et al. (1999) to C11.6 LAS was 0.35 mg/L. Using the acute to 

chronic ratio calculation (documented in Annex 3 of the LAS SIAR), the 

EC50/3 for Microcystis is 0.3 mg/L. This is a critical study for this SIDS 

endpoint. 

Reference: Lewis, M.A. and Hamm, B.G. 1986. Environmental modifications of the 

photosynthetic response of Lake Plankton to surfactants and significance to a 

laboratory-field comparison. Wat. Res. 20:1575-1582. 

 Reliability: 2 Valid with restrictions 

 (t) 

Type of Test: Static [ ]; semi-static [ ]; flow-through [ ] 

 Open-system [ ]; closed-system [ ]; not stated [X] 

Species: Plectonema boryanum (algae); strain 597 

Exposure Period: not stated 

Effect Criteria: Growth rate 

Results: NOEC = 20 mg/L 

 LOEC = 30 mg/L 

Analytic Monitoring: Yes [ ]; No [ ]; ? [X] 

 Method: LAS concentrations of 1, 5, 10, 15, 20 and 30 mg/L were prepared in 

 Deionized, sterilized double-distilled glass water. Algae were grown 

 in Bold’s medium. 

GLP: Yes [ ]; No [X]; ? [ ] 

Test Substance: C11.2 LAS 

Remarks: Growth rate was reduced at 30 mg/L concentrations of LAS as indicated by 

spectrophotometer readings and dry weight. The NOEC normalized by van 

de Plassche et al. (1999) to C11.6 LAS was 15 mg/L. 

Reference: Dhaliwal, A.S., Campione, A., and Smaga, S. 1977. Effect of linear 

alkylbenzene sulfonate (C11.2 LAS) on the morphology and physiology of 

Plectonema boryanum and Chlamydomonas reinhardi. J. Phycol. 12:18. 

 Reliability: 4 Not assignable This study was given a reliability score of 4 because the 

document reviewed was an abstract. However, these data were considered 

reliable as part of a weight-of-evidence approach in the analysis conducted 

by van de Plaasche et al. (1999). 
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4.4 TOXICITY TO BACTERIA

(a) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: activated sludge 

 Exposure Period: 3 hour 

 Results: EC50 (Na LAS-C11) = 760 mg/L 

 EC50 (Na LAS-C11.6) = 550 mg/L 

 EC50 (Na LAS-C13) = 650 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: OECD 209 Activated Sludge Respiration Inhibition Test. 1984. 

 GLP: Yes [X] No [ ] ? [ ]

Test substance: Three different alkyl chain lengths of LAS (C11, C11.6, C13 sodium salts), with 

the following homologue distributions. 

Alkyl Chain Length Distributions (%) 

 LAS C11 LAS C11.6 LAS C13

<C10 1.5 0.4 -- 

C10 29.0 8.9 1.0 

C11 39.0 33.7 3.5 

C12 28.5 31.0 17.8 

C13 1.8 24.0 37.0 

C14 0.2 2.0 40.4 

>C14 -- -- 0.3 

LAS MW 

(as Na-LAS) 334 343 363 

Remarks: The purpose of the study was to determine the toxicity of three commercial 

LAS products to the activated sludge of a treatment plant basically operating 

on domestic sewage. A contact time of 3 hours instead of 15 minutes was 

chosen to better simulate the real residence time used in wastewater 

treatment plants (4-6 hours). The EC50 values are far above environmental 

concentrations and therefore provide a high margin of safety. The 3-hour 

EC50 range for the reference substance (3,5-dichlorophenol) ranged from 20-

30 mg/L, within the valid range of 5-30 mg/L. 

Reference: Verge C. and Moreno, A. 1996b. Toxicity of anionic surfactants to the 

bacterial population of a waste water treatment plant. Tenside Surf. Det. 

33:323-327. 

Reliability: 2 Valid with restrictions 

(b) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: activated sludge 

 Exposure Period: 3 hour 

 Results: EC50 (Na LAS-C10) = 1042-1200 mg/L 

 EC50 (Na LAS-C11) = 740-782 mg/L 

 EC50 (Na LAS-C12) = 500-723 mg/L 

 EC50 (Na LAS-C13) = 700-795 mg/L 

 EC50 (Na LAS-C14) = 900-1045 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: OECD 209 Activated Sludge Respiration Inhibition Test. 1984. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Five different pure homologues of LAS (C10, C11, C12, C13, C14 sodium salts), 

with the following homologue distributions. 
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UNEP PUBLICATIONS 199

 Pure Homologues (%) 

 LAS C10 LAS C11 LAS C12 LAS C13 LAS C14

<C10 0.5 -- 0.4 -- -- 

C10 96.8 5.5 13.9 0.7 -- 

C11 2.7 93.7 84.5 9.8 0.6 

C12 -- 0.8 1.2 78.3 1.0 

C13 -- -- -- 11.2 15.4 

C14 -- -- -- -- 82.1 

>C14 -- -- -- -- 0.9 

LAS MW 

(as Na-LAS) 320.7 333.7 346.4 362.3 373.7 

Remarks: The purpose of the study was to determine the toxicity of five pure 

homologues of LAS to the activated sludge of a treatment plant basically 

operating on domestic sewage. A contact time of 3 hours instead of 15 

minutes was chosen to better simulate the real residence time used in 

wastewater treatment plants (4-6 hours). The EC50 values are far above 

environmental concentrations and therefore provide a high margin of safety. 

The 3-hour EC50 range for the reference substance (3,5-dichlorophenol) 

ranged from 20-30 mg/L, within the valid range of 5-30 mg/L. 

Reference: Verge C. and Moreno, A. 1996b. Toxicity of anionic surfactants to the 

bacterial population of a waste water treatment plant. Tenside Surf. Det. 

33:323-327. 

Reliability: 2 Valid with restrictions 

 

(c) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: activated sludge 

 Exposure Period: 15 minute 

 Results: EC50 = 107-152 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: ESD-VIII-D-1, Issue II (9/8/80) 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Effect: inhibition of respiration. 

Nominal concentrations (expected deviation <20%). Mixed Liquor 

Suspended Solids 53.6-76.1 mg/g VSS/Sewage. Static, 25oC. Activated 

sludge (2600 mg SS/L) 

 Reference: European Commission. 2000s. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

27896, 27897, 27915. 

 Reliability: 4 Not assignable. The original study was not available for review. Summary 

included for competeness. 

 

 (d) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: Pseudomonas putida (Bacteria) 

 Exposure Period: 18 hour 

 Results: EC50 = 60.9-63.5 mg/L 

 EC10 = 52.7-56.6 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: Bacterial toxicity test according to DIN 38412 part 8. A total of 6 

concentrations were tested (40-80 mg/L) under GLP conditions. 

 GLP: Yes [X] No [ ] ? [ ]
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 200

 Test substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6; activity 91.3%, 

 Remarks: Results show EC50 and EC10 values for two tests. 

 Reference: Scholz, N. 1993. Bestimmung der bacterientoxizitat von Marlon A 390 in 

Pseudomonas-zellvermehrungs-Hemmtest. Huels-Final Report No. PZ93/10. 

 Reliability: 2 Valid with restrictions

 

 (e) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: Pseudomonas putida (Bacteria) 

 Exposure Period: 30 minute 

 Results: EC50 = 350 mg/L 

 EC0 = 250 mg/L 

 Analytical monitoring: Yes [ ] No [ ] ? [X] 

 Method: DIN 38412 Teil 27 (respiration inhibition test) 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Data refer 

to 100% active ingredient. 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 (f) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: Pseudomonas putida (Bacteria) 

 Exposure Period: 16 hour 

 Results: EC50 = 150 mg/L 

 EC0 = 50 mg/L 

 Analytical monitoring: Yes [ ] No [ ] ? [X] 

 Method: DIN 38412 Teil 8 (cell multiplication inhibition test) 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Data refer 

to 100% active ingredient 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 

 (g) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: Pseudomonas putida (Bacteria) 

 Exposure Period: 30 minute 

 Results: NOEC = 64 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: DIN 38412, Teil 27 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS, average chain length 11.8 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Synthetic 

water; static; pH 7.2+

/-0.2; 20oC. Effect: Inhibition of oxygen consumption. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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 Reference: European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KgaA. 

 Reliability: 4 Not assignable 

 (h) 

 Type: Aquatic [X]; Field [ ]; Soil [ ]; Other [ ]

 Species: Pseudomonas putida (Bacteria) 

 Exposure Period: 16 hour 

 Results: NOEC = 30 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: DIN 38412, Teil 8 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS, average chain length 11.8 (CAS #68411-30-3) 

 Remarks: Synthetic medium; static; pH 7.4+

/-0.3; 21oC. Effect: growth inhibition. 

Feitjel et al. reviews this study and also reports an NOEC = 35 mg/L for C11.6

LAS. 

 Reference: Feijtel, T.C.J., Matthijs, E., Rottiers, A., Rijs, G.B.J., Kiewiet, A., and de 

Nijs, A. 1995. AIS/CESIO environmental surfactant monitoring 

programme. Part 1: LAS monitoring study in “de Meer” STP and receiving 

river “Leidsche Rijn” Chemosphere 30:1053-1066. 

 Reliability: 4 Not assignable 

 (i) 

 Results: Based on digester performance, even a high and atypical concentration of 

LAS (30 g/kg) did not inhibit microbial populations present in STP activated 

sludge digesters. 

 Remarks: The study was designed to monitor LAS during the different steps of 9 

different standard sewage treatment plants operating mainly with domestic 

sewage. LAS-specific analytical methods were used. More details on the 

study can be found in the summary at 3.2(f). 

 Reference: Berna, J.L., de Ferrer, J., Moreno, A., Prats, D. and Ruiz Bevia, F. 1989. 

The fate of LAS in the environment. Tenside Surf. Det. 26:101-107. 

 Reliability: 4 Not assignable. Treatment plant operational records are not available for 

review. 

4.5 CHRONIC TOXICITY TO AQUATIC ORGANISMS 

4.5.1 CHRONIC TOXICITY TO FISH 

 (a) 

 Type of Test: Static [ ]; semi-static [X]; flow-through [ ] 

 Open-system [X]; closed-system [ ]; not stated [ ] 

 Species: Brachydanio rerio (Zebra Fish, fresh water) 

 Exposure Period: 14 days 

 Effect Criteria: Mortality, behavior 

 Results: NOEC = 2.0 mg/L 

 LOEC = 4.0 mg/L 

 Analytic Monitoring: Yes [ ]; No [X]; ? [ ] 

 Method: Based on UBA-Verfahrensvorschlag:Verlaengerter Toxizitaetstest beim 

Zebrabaerbling Brachydanio rerio, Bestimmung der Schwellenkonzentration 

der letalen und anderer Wirkungen, NOEC, mindestnes 14 Tage. This 

method conforms with OECD Guideline 204. Ten fish were exposed to each 

of seven concentrations (0.2, 0.4, 0.8, 1.6, 2.0, 4.0 and 8.0 mg/L) and the 

controls. Test chambers were 10-L basins containing 5-L of copper- and 

chlorine-free drinking water, maintained in a 16:8 light:dark illumination 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 202

cycle. The NOEC normalized by van de Plassche et al. (1999) to C11.6 LAS 

was 2.3 mg/L. 

 GLP: Yes [ ]; No [X]; ? [ ] 

 Test Substance: Marlon A 350 LAS (CAS #68411-30-3; Benzenesulfonic acid, C10-13- alkyl 

derives., sodium salts, 25.7% activity) 

 Reference: Henkel KGaA, Biological Research and Product Safety/Ecology: 

unpublished results (Test substance number Fi 5959). 

 Reliability: 2 Valid with restrictions. Duration of test considered too short for a chronic 

study, therefore not included in SIAR Table 12A. 

 (b) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Pimephales promelas (Fish, fresh water) 

 Exposure period: 30 day 

 Effect criteria: Fry survival 

 Results: NOEC = 1 mg/L 

 LOEC = 2 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] HPLC 

 Methods: Two replicates of 100 egg-fry stage fathead minnows were exposed for 30 

days to LAS under the following conditions: Hardness 41 mg/L as CaCO3; 

pH 7.2; temperature 24o

C. The exchange rate was 1 to 3 volume 

changes/day. Test chambers were 3500 mL volume. The studies were 

conducted at EG&G Bionomics (now Springborn Smithers Laboratory). 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: Commercial C10-13 LAS, sodium salt (CAS #68411-30-3); C10 5%, C11 27%, 

C12 53%, C13 13%; 2-phenyl 23%. 

 Remarks: Carboxylated intermediates formed in the biodegradation of LAS exhibit 

toxicity several orders of magnitude less than LAS; LC50 values were >144 

mg/L and >52 mg/L for sulfophenyl butarate and sulfophenyl undecanoate, 

respectively. NOEC based on fry survival. Egg hatchability and fry growth 

were less sensitive. This is a key study for chronic aquatic toxicity to fish 

(see SIAR Table 12). 

 Reference: Swisher, R.D., Gledhill, W.E., Kimerle R.A. and Taulli, T.A. 1978. 

Carboxylated intermediates in the biodegradation of linear alkylbenzene 

sulfonates (LAS). VII International Congress on Surface Active Substance, 

 Proceedings, Moscow, 1976 4:218-230. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Type of Test: Static [ ]; semi-static [X]; flow-through [ ] 

 Open-system [X]; closed-system [ ]; not stated [ ] 

 Species: Poecilia reticulata (Fish, Guppy, fresh water) 

 Exposure Period: 28 days 

 Effect Criteria: Mortality, behavior, and growth 

 Results: NOEC = 3.2 mg/L 

 LOEC = 10 mg/L 

 Analytic Monitoring: Yes [ ]; No [X]; ? [ ] 

 Method: Fish were 3-4 weeks old at test initiation. Fifty fish were used per group. 

Temperature was maintained at 23 ± 2°C. The test volume (10-L per 

chamber) was renewed three times per week. Circadian lighting (16:8 

light:dark) was used. Fish were fed a Tetramin/Tetraphyll mixture. 

Dissolved oxygen, water hardness and pH were measured during the study. 

 GLP: Yes [ ]; No [ ]; ? [X] 

 Test Substance: LAS, 42.4% activity (C8 <1%, C9 16.5%, C10 23%, C11 20%, C12 18%, C13

16%, C14 6.5%); average = C11.1
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 Remarks: The only effect (98% mortality at 10 mg/L) occurred within 2 days of study 

initiation. The NOEC normalized by van de Plassche et al. (1999) to C11.6

LAS was 3.2 mg/L. 

 Reference: Canton, J.H. and Slooff, W. 1982. Substitutes for phosphate containing 

washing products: Their toxicity and biodegradability in the aquatic 

environment. 

 Reliability: 2 Valid with restrictions. Duration of test considered too short for a chronic 

study, therefore not included in SIAR Table 12A. 

 (d) 

 Type of Test: Static [ ]; semi-static [ ]; flow-through [X] 

 Open-system [X]; closed-system [ ]; not stated [ ] 

 Species: Oncorhynchus mykiss (Fish, Rainbow Trout, fresh water) 

 Exposure Period: 14 days 

 Effect Criteria: Mortality 

 Results: 14 day LC50 = 0.12 mg/L 

 Analytic Monitoring: Yes [ ]; No [ ]; ? [X] 

 Method: Rainbow trout at different developmental stages (egg [160-200 eggs per 

concentration], alevin with partially absorbed yolk sac [2-3 days old], alevin 

[60 days old], and adult [270-300 days old]) were exposed to LAS for 14 

days. Temperature was maintained at about 15°C, dissolved oxygen at 

greater than 80% of saturation, pH at 7.3-7.4, and water hardness of 290-310 

mg/L as CaCO3. 

 GLP: Yes [ ]; No [ ]; ? [X] 

 Test Substance: C12 LAS, 45% activity 

 Remarks: The egg was the most sensitive life stage in the 14 day tests, in contrast to the 

24 hour tests, which showed the egg to be the least sensitive (alevins with 

partially absorbed yolk sac were the most sensitive in the 24 hour tests). 

Malformations were seen only in embryos treated with lethal concentrations. 

A NOEC value was not determined in the study and the data provided are 

inadequate to calculate an EC20 value. 

 Reference: Vailati, G., Calamari, D. and Marchetti, R. 1975. Effetti dell’alchilbenzene 

sofonato (LAS) sugli staid di sviluppo del Salmo gairdneri Rich. Istituto di 

Ricerca sulle Acque (CNR) Sezione di Idrobiologia Applicata (Milano). 

 Reliability: 2 Valid with restrictions. Duration of test considered too short for a chronic 

study, therefore not included in SIAR Table 12A. 

 (e) 

 Type of Test: Static [X]; semi-static [ ]; flow-through [ ] 

 Open-system [X]; closed-system [ ]; not stated [ ] 

 Species: Tilapia mossambica (Fish, Tilapia, fresh water) 

 Exposure Period: 90 days 

 Effect Criteria: Feeding, growth rate, fecundity, yield 

 Results: NOEC = 0.25 mg/L 

 LOEC = 0.51 mg/L 

 Analytic Monitoring: Yes [ ]; No [ ]; ? [X] 

 Method: Tests generally followed the standard methods of APHA 1975, with the 

following specifics. Tests were conducted in outdoor earthen vats (62 cm 

diameter, 30 cm mean depth) containing 60-L of borehole water and 5 kg of 

uncontaminated soil. Borehole water is unchlorinated water with the 

following parameters: pH 7.1 ± 0.1, dissolved oxygen 10 mg/L, hardness 290 

mg/L as CaCO3, and temperature 27.9 ± 0.14 °C. Fifteen fish purchased 

from local farms (35 mm, 0.786 g) and acclimated to the test conditions for 

168 hours were added per vat. Test concentrations were 0.25, 0.38, 0.51, and 

1.10 mg/L. Fish were exposed six times at 15 day intervals with the water 

renewals and were fed daily with a 1:1 mixture of rice bran and mustard oil 
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cake. Standard acute toxicity tests were also conducted in the laboratory. 

Statistical analysis was done using F and t tests and the significance of any 

change was measured at a 5% level of probability. 

 GLP: Yes [ ]; No [X]; ? [ ] 

 Test Substance: LAS (Parnol J Liquid), 20% activity; clear yellow liquid; pH in solution was 

8 ± 1 

 Remarks: The feeding rates decreased significantly at 0.25, 0.38 and 1.10 mg/L. Fish 

showed erratic behaviour, irregular opercular movement, and at higher 

concentrations, blood exuded from the base of the pectoral and pelvic fins 

and head. No apparent difference in condition factor (K) was observed at any 

concentration. The maturity index (MI) of both male and female fish 

appeared to decrease at all concentrations, but the biological significance of 

this is questionable because historic control values for this parameter were 

not provided and the magnitude of the response did not increase with dose. 

Fecundity decreased at 0.51 mg/L but not at 1.10 mg/L. The gastrosomatic 

index (GSI) was significantly different at 0.51 and 1.10 mg/L. Based on the 

most reliable endpoints (GSI and fecundity), the NOEC would be 0.38 mg/L 

and the LOEC would be 0.51 mg/L. However, the study is incompletely 

documented, so details of the test substance composition and testing 

procedure are uncertain. True replicates were not used so statistics can not be 

validly conducted, though they are reported by the authors. In view of these 

limitations, and previous evaluations of the study which have reported a 

NOEC of 0.25 mg/L (van de Plassche et al., 1999), a conservative 

(protective) NOEC for this study is 0.25 mg/L. This is a critical study for this 

SIDS endpoint. 

 Reference: Chattopahyay, D.N. and Konar, S.K. 1985. Acute and chronic effects of 

linear alkyl benzene sulfonate on fish, plankton, and worm. Environment & 

Ecology, 3:258-262. 

 Reliability: 2 Valid with restrictions. 

 (f) 

 Type of test: Various types and durations of tests. 

 Results: The article compiles the no observed effect concentration (NOEC) values for 

many tests conducted on an assortment of species. The following table 

shows the geometric mean NOEC values for each fish species (n = number of 

studies included for each species). 

Species Geometric mean 

NOEC (mg/L) 

N 

Brachydanio rerio 2.3 1 

Pimephales promelas 0.87 14 

Poecilia reticulate 3.2 1 

Oncorhynchus mykiss 0.34 7 

Tilapia mossambica 0.25 1 

 

 Remarks: All data were from tests conducted on commercial LAS with C10-13 alkyl 

chains and average carbon lengths close to C11.6 and C11.8. The NOEC values 

have been normalized using QSARs to the average structure of C11.6 LAS. 

 Reference: van de Plassche, E.J., DeBruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J., and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: Linear alkyl benzene sulfonate, 

alcohol ethoxylates, alcohol ethoxylated sulfates, and soap. Environ. 

Toxicol. Chem. 18: 2653-2663. 

 Reliability: 4 Not assignable This study was given a reliability score of 4 because the 

original reports reviewed by the authors were not directly reviewed in the 

compilation of this robust summary. 
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 (g) (Rainbow trout)

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; other [ ]; open-system [X]; 

closed-system [ ] 

 Species: Salmo gairdneri (Oncorhyncus mykiss, fish, estuary, fresh water) 

 Endpoint: Length of fish [ ]; Weight of fish [ ]; 

 Reproduction rate [ ]; Other [X] Growth 

 Exposure period: 28 day 

 Results: NOEC = 0.43-0.89 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: Crossland, N O. 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: C10-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Mean 

NOEC: 0.62 mg/1 (2 tests). Huels AG judged study quality to be good. Tap 

water with hardness 84-153 mg/L CaCO3; pH 7.1-8.7; flow-through; 14-

16oC; age of fish at start of study: 6 months. 

 Reference: European Commission. 2000k. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

CT/R153/01, CT/R153/06. 

 Reliability: 4 Not assignable. The original studies were not available for review. 

 (h) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; other [ ]; open-system [X]; 

closed-system [ ] 

 Species: Salmo gairdneri (Fish, estuary, fresh water) 

 Endpoint: Length of fish [ ]; Weight of fish [ ]; 

 Reproduction rate [ ]; Other [X] Growth, Hatching, Survival 

 Exposure period: 70 day 

 Results: NOEC = 0.23 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: Unilever Research Protocol, Early Life Stage (ELS) test. 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: C10-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Huels 

AG judged study quality to be good. Tap water with hardness 70-133 mg/L 

CaCO3; pH 7.3-7.8; flow-through; 8.5- 11.5oC; life-stage: ELS. 

 Reference: European Commission. 2000j. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

CT/R118/03. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (i) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; other [ ]; open-system [X]; 

closed-system [ ] 

 Species: Salmo gairdneri (Fish, estuary, fresh water) 

 Endpoint: Length of fish [ ]; Weight of fish [ ]; 

 Reproduction rate [ ]; Other [X] Growth, Hatching, Survival 

 Exposure period: 70 day. 

 Results: NOEC = 0.3-0.35 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: Unilever Research Protocol. 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: C10-13 LAS (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Mean 

NOEC: 0.32 mg/1 (2 tests). Huels AG judged study quality to be good. 
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Nominal concentrations (expected <20%). Tap water with hardness 64-159 

mg/L CaCO3; pH 6.6-8.0; flow-through; 7.5-15 oC; life-stage: ELS 

 Reference: European Commission. 2000l. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Procter & Gamble, 1991, 

CT/R89/01, CT/R89/02. 

 Reliability: 4 Not assignable. The original studies were not available for review. 

 (j) (Fathead Minnow)

 Type of test: static [ ]; semi-static [ ]; flow-through [ ]; other [X]; open-system [X]; 

closed-system [ ] 

 Species: Pimephales promelas (Fish, fresh water) 

 Endpoint: Length of fish [ ]; Weight of fish [ ]; 

 Reproduction rate [ ]; Other [X] Survival 

 Exposure period: 196 day 

 Results: NOEC = 0.63 mg/L; LOEC = 1.2 mg/L (based on effects on fry survival) 

Hatchability and growth were not significantly affected. 

 Analytical monitoring: Yes [ ] No [ ] ? [X]

 Method: Either a serial or proportional dilution unit was used to provide continuous 

exposures to fathead minnows. Each of the four test concentrations plus 

control received 12 randomly assigned fish obtained from ponds at the 

Newtown Fish Farm, Ohio Division of Wildlife. Pieces of half-tile were 

placed in each 10-gal aquarium for spawning sites. After spawning had been 

completed, the cluster of eggs was removed and counted. Four replicates of 

100 eggs from each concentration were reared for 14 days and mortality of 

eggs and fry recorded daily. Mean dissolved oxygen, water hardness, and 

pH ranged from 5.84-6.42 mg/L, 194-214 mg/L CaCO3, and 7.50-7.95, 

respectively. Test concentrations were 0.34, 0.63, 1.2 and 2.7 mg/L. 

 GLP: Yes [ ] No [ ] ? [X] 

 Test substance: LAS, activity: 60.8%; equivalent MW = 348 

 Reference: Pickering, Q.M. and Thatcher, T.O. 1970. The chronic toxicity of linear 

alkylate sulphonate (LAS) to Pimephales promelas Rafinesque. Water 

Pollut. Control Fed. 42:243-254. 

 Reliability: 2 Valid with restrictions 

 (k) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Pimephales promelas (Fish, fresh water) 

 Exposure period: 28 day 

 Results: NOEC (C11.8) = 0.9 mg/L 

 NOEC (C13) = 0.15 mg/L 

 Analytical monitoring: Yes [ ] No [ ] ? [X] 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS (CAS #68411-30-3), average chain lengths 11.8 and 13 

 Remarks: Observations were made of the number of spawnings, total eggs produced, 

and number of eggs per female. Data were obtained from the literature. 

 Reference: Maki, A.W. 1979. Correlations between Daphnia magna and fathead 

minnow (Pimephales promelas), chronic toxicity values for several classes 

of test substances. J. Fish. Res. Bd Can. 36, 411-421. 

 Reliability: 4 Not assignable. This study was given a reliability score of 4 because the 

publication is a summary of previous tests and the original study reports were 

not available for review. 

 (l) 

 Type of Test: Static [ ]; semi-static [ ]; flow-through [ ] 

 Open-system [ ]; closed-system [ ]; not stated [X] 
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 Species: Pimephales promelas (Fish, Fathead Minnow, fresh water) 

 Exposure Period: Up to 30 days post-hatch 

 Effect Criteria: Embryolarval/fry survival 

 Results: NOEC = 1.02 mg/L 

 Analytic Monitoring: Yes [ ]; No [ ]; ? [X] 

 Method: The publication summarizes the results of a series of critical life stage 

(embryolarval) tests, which are defined as exposure during the embryogenic 

period (incubation of the eggs), followed by exposure of fry for a period of 

30-days after hatching for warm water fish with embryogenic periods ranging 

from 1 to 14 days. 

 GLP: Yes [ ]; No [ ]; ? [X] 

 Test Substance: C11.7 LAS (commercial blend of C10 8%, C11 29%, C12 34%, C13 29%) 

 Remarks: All of the original studies summarized in this publication were conducted at 

EG&G Bionomics (now Springborn Smithers Labs) using standard protocols. 

The minimum threshold concentration, defined as the lowest concentration 

causing significant effect on any parameter, was reported as >1.02 mg/L 

<2.05 mg/L. The NOEC normalized by van de Plassche et al. (1999) to C11.6

LAS was 1.1 mg/L. 

 Reference: Macek, K.J. and Sleight, B.H. III. 1977. Utility of toxicity tests with embryos 

and fry of fish in evaluating hazards associated with the chronic toxicity of 

chemicals to fishes. Aquatic Toxicology and Hazard Evaluation, ASTM STP 

634. Mayer, F.L. and Hamelink, J.L, Eds. American Society for Testing and 

Materials, pp. 137-146. 

 Reliability: 4 Not assignable. This study is given a reliability of 4 because the 

publication is a summary of previous tests and the original study reports were 

not available for review. 

 (m) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; other [ ] 

 open-system [X]; closed-system [ ] 

 Species: Lepomis macrochirus (Fish, fresh water) 

 Exposure period: 28 day 

 Results: NOEC = 1.0 mg/L for bluegill 

 LOEC = 2.0 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: The effect of LAS on the structure and function of microbial communities 

was studied in a flow-through model ecosystem containing several trophic 

levels. Duplicate 19-L glass aquaria containing model ecosystems at four 

nominal concentrations (0.5, 1.0, 2.0, 4.0 mg/L) contained water and 2.5 cm 

lake sediment (Winton Lake, Cincinnati, OH) and several trophic levels 

(bacteria, algae, macrophytes [Elodea canadensis,Lemna minor], 

macroinvertebrates [Daphnia magna, Paratanytarsus parthenogenica], and 

fish [Lepomis macrochirus]). Flow rate in the proportional diluter delivered 

approximately 8 replacement volumes per day. Additionally, at each cycle of 

the diluter, 1.5 mL of a Daphnia food suspension diluted with a culture of 

Selenastrum was added to each chamber. Following an initial 3 day 

acclimation period to analytically confirm test concentrations, 4 glass 

periphyton slides (5 x 5 cm), 8 vegetative shoots of Elodea, 10 early instar 

Daphnia, 25 midge eggs and 5 pre-weighed juvenile bluegills (2.5-5.0 cm 

length) were added to each aquarium. Fish were screened from access to the 

macroinvertebrates by a 60 mesh stainless steel screen and were fed a daily 

supplement of frozen brine shrimp. Test duration was 28 days. Effects 

monitored included population and community effects. Nominal 

concentrations were confirmed with MBAS analysis. 

 GLP: Yes [ ] No [ ] ? [X]
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 Test substance: LAS; C14-LAS chain length C12 (91% purity) plus unlabeled LAS with 

average chain length C11.6 (C10 9.7%, C11 27.9%, C12 54.4%, C13 8.0%; 95% 

purity) (tested together) 

 Remarks: Dissolved oxygen concentrations ranged between 7.0 and 9.0 mg/L. 

Temperature was maintained at 2°C and the mean pH was 8.1 ± 0.2. 

Bluegill fish growth was reduced at the 2.0 and 4.0 mg/L concentrations but 

not at 0.5 or 1.0 mg/L. Results for the other species and community 

parameters tested are summarized in Section 4.7 (i). Juvenile growth was the 

most sensitive fish endpoint in this model ecosystem study and thus is 

appropriate to use for chronic toxicity. This is a key study for chronic aquatic 

toxicity to fish (see SIAR Table 12). 

 Reference: Maki, A.W. 1981. A Laboratory model ecosystem approach to 

environmental fate and effects studies. Unpublished Internal Report, 

Environmental Safety Department Procter and Gamble Company, Cincinnati, 

Ohio. 

 Reliability: 2 Valid with restrictions 

4.5.2 CHRONIC TOXICITY TO AQUATIC INVERTEBRATES

Water-only Exposures 

 (a) 

 Type of test: static [ ]; semi-static [ ]; flow-through [ ]; open-system [ ]; closed-system [ ]; 

not stated [X] 

 Species: Ceriodaphnia sp. (Crustacea) 

 Endpoint: Mortality [ ]; Reproduction [X] 

 Exposure period: not stated 

 Results: NOEC = 3 mg/L 

 Analytical monitoring: Yes [ ] No [ ] ? [X] 

 Method: Standard laboratory methods. 

 GLP: Yes [ ] No [] ? [X] 

 Test substance: C11.7 LAS 

 Remarks: Further information regarding study conditions was not provided in this peerreviewed publication. 

 Reference: Kimerle, R.A. 1989. Aquatic and terrestrial ecotoxicology of linear 

alkylbenzene sulfonate. Tenside Surfactants Detergents, 26:169-176. 

 Reliability: 4 Not assignable. Data table cites an unpublished report by Procter & 

Gamble. 

 (b) 

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; open-system [ ]; closed-system 

[X]; not stated [ ] 

 Species: Ceriodaphnia sp. (Crustacea) 

 Endpoint: Mortality [X]; Reproduction [X] 

 Exposure period: 7 day 

 Results: NOEC = 0.7 mg/L (geometric mean of two tests); 0.84 mg/L (normalized for 

C11.8 LAS) 

 NOEC = 0.5 mg/L (trout chow/algae diet) 

 EC10 = 0.99 mg/L (yeast diet); normalized EC10 = 1.18 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ] 

 Method: ASTM (Commotto 1982; Mount and Norberg 1983). Ceriodaphnia were 

cultured individually in 50 mL beakers containing 30 mL culture water. 

Two tests were conducted, representing animals fed with two different diets 

(troutchow and algae – Selenastrum capricornutum – or baker’s yeast). 

They were acclimated to the test conditions and diet for two generations 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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before use in toxicity testing. Ten 50 mL beakers containing 30 mL of test 

solution were used for each test concentration. Nominal concentrations were 

0.5, 1.0, 2.0, 3.5, 5.0 and 7.0 mg/L plus controls. Each beaker contained one 

Ceriodaphnia (for a total of 10 daphnids per concentration). Tests were 

begun with neonate animals (<24 hours old) and lasted seven days. The 

young were counted and removed from each beaker daily. All test chambers 

were cleaned and renewed with fresh test solution three times (on the second, 

fourth, and sixth day). Total water hardness (Ohio river water) was 110 ± 9 

mg/L as CaCO3, pH was 7.4 ± 0.2, dissolved oxygen was 9.7 ± 0.8 mg/L, 

and total suspended solids was 87 ± 106. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: C11.8 LAS; activity 30.8% 

 Results: Ceriodaphnia fed trout chow/algae showed no dose-dependent response for 

any endpoint, so no EC20 could be calculated. The NOEC is considered to be 

5.0 mg/L based on 100% mortality at 7.0 mg/L. Results of the test run with 

the trout chow/algae diet are shown in the following table: 

 

LAS 

Concentration 

Percent 

Mortality 

Total 

Reproduction

1st Day of 

Reproduction 

Reproduction 

per Individual Broods Brood Size 

0 10 87 4.7 9.7 2.4 4.0 

0.5 0 69 5.0 6.9 2.1 3.4 

1.0 10 32 5.6* 3.6* 1.4* 2.4* 

2.0 0 42 5.0 4.2* 1.8 2.2* 

3.5 0 82 5.6* 8.2 2.0 4.2 

5.0 0 105 4.7 11.6 2.3 4.9 

7.0 100* 15 4.0 5.0* --* 5.0 

* Significantly different from the control (p<0.05) 

 Brood size and reproduction gave good dose-dependent responses for 

organisms fed yeast. Brood size was the most sensitive endpoint and 

resulted in an EC20 of 1.44 mg/L. Reproduction resulted in an EC20 of 2.70 

mg/L. Results of the test run with the yeast diet are shown in the following 

table: 

LAS 

Concentration 

Percent 

Mortality 

Total 

Reproduction

1st Day of 

Reproduction 

Reproduction 

per Individual Broods Brood Size 

0 0 229 4.0 22.9 2.9 8.0 

0.5 0 208 3.9 20.8 2.9 7.3 

1.0 0 178 4.0 17.8 2.9 6.1* 

2.0 10 145 4.0 16.1* 3.0 5.4* 

3.5 10 78 4.4 8.7* 2.4 3.4* 

5.0 10 8 6.6* 0.9* 0.6* 1.8* 

7.0 100* 0 --* --* --* --* 

* Significantly different from the control (p<0.05) 

 

 Remarks: Later experience with Ceriodaphnia has shown that a yeast diet is not 

optimum for this species. A geometric mean of 2.68 mg/L can be calculated 

for the two tests. This is a critical study for this SIDS endpoint. 

 Reference: 1) Procter & Gamble. 2004. Ceriodaphnia sp. Chronic toxicity test. 

Unpublished report, September 9, 2004. 

 2) Comotto, R.M. 1982. Proposed standard practice for conducting renewal 

life cycle toxicity tests with Daphnia magna. Draft 1, August 1982, ASTM 

committee E-47. American Society for Testing and Materials, Philadelphia, 

PA. 
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 3) Mount, D.I. and Norberg, T.J. 1983. A seven-day life cycle cladoceran 

toxicity test. Pre-publication. USEPA (Duluth). 

 4) Snedecor, G.W. and Cochran, W.G. 1967. Statistical Methods. 6th Edition. 

Iowa State University Press, Ames, IA. 

 5) Versteeg, D.J., Belanger, S.E., and Carr, G.J. 1999. Understanding singlespecies and model ecosystem sensitivity: Data-based comparison. Environ. 

Toxicol. Chem. 18:1329-1346. 

 Reliability: 2 Valid with restrictions (actual exposure concentrations might have been 

less than nominal values; not GLP) 

 (c) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [ ]; closed-system 

[X]; not stated [ ] diluter sytem based on Mount and Brungs 1967 

 Species: Daphnia magna. (Crustacea) 

 Endpoint: Mortality [ ]; Reproduction [X] 

 Exposure period: 21 day 

 Results: NOEC = 1.18 mg/L 

 LOEC = Not reported 

 Analytical monitoring: Yes [X] No [ ] ? [ ] MBAS method 

 Method: A modified 0.5-L proportional diluter was used to deliver four replicates to 

each of five test concentrations plus a control. No solvent was used. Five 

Daphnia (<12 hours old) were randomly assigned to each replicate. 

Daphnia were fed a suspension of ground trout chow and alfalfa daily. The 

dilution water was carbon and reverse osmosis filtered well water. Water 

quality parameters were measured at test initiation and at intervals of 3-5 

days for the remainder of the test. Tests were run at 21 ± 1 °C, dilution water 

hardness 120 mg/L as CaCO3, pH 7.4 ± 0.2, and dissolved oxygen 8.5 ± 0.5 

mg/L. F0 mortality was recorded at 24-h, 96-h, 7-d and daily thereafter. 

Total number of F1 produced, mean brood size, and the percentage of days 

young were produced within each replicate was measured for all five 

concentrations and the controls. Mortality was evaluated using a 

computerized Probit procedure. The no effect concentration was determined 

as the highest measured concentration with no perceivable effects. This 

study was conducted in 1977. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: C11.8 LAS; mean phenyl position 3.76; mean molecular weight = 345 

 Remarks: The most sensitive indicator of reproductive inhibition was the total number 

of young produced. This is a key study for chronic aquatic toxicity to 

invertebrates (see SIAR Table 12). 

 Reference: Maki, A.W. 1979. Correlations between Daphnia magna and fathead 

minnow (Pimephales promelas) chronic toxicity values for several classes of 

test substances. J. Fish. Res. Board Can. 36:411-421. 

 Reliability: 2 Valid with restrictions. 

 (d) 

 Species: Daphnia magna

 Results: NOEC = 1.4 mg/L (12 records) 

 Test Substance: LAS normalized to C11.6

 Remarks: NOEC is geometric mean of 12 records compiled from literature reviews and 

normalized to C11.6. 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap. 

Environ. Toxicol. Chem. 18:2653-2663. 
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 Reliability: 4 Not assignable. This study was given a reliability score of 4 because all the 

original reports reviewed by the authors were not directly reviewed in the 

compilation of this robust summary. 

 (e) 

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; open-system [ ]; closed-system [

] 

 Species: Daphnia magna (Crustacea) 

 Endpoint: Mortality [X]; Reproduction rate [X]

 Exposure period: 21days 

 Results: NOEC = 1.25-3.25 mg/L; LOEC = 2.25-3.75 mg/L 

Geometric Mean NOEC = 1.99 mg/L (mean of studies using 5 different 

diets) 

 Analytical monitoring: Yes [ ] No [ ] ? [X]

 Method: ASTM proposed standard practice for conducting renewal life cycle toxicity 

tests with Daphnia magna. Draft No. 1, August 1982. Ten 250 m/L beakers 

were used for each test concentration. Seven beakers contained one daphnid 

each and three beakers contained five daphnids each, for a total of 22 

daphnids per concentration. All conditions were maintained as per protocol. 

 GLP: Yes [ ] No [] ? [X]

 Test substance: Commercial C10-13 LAS, average chain length C11.8 (CAS #68411-30-3). 

 Remarks: NOEC and LOEC values represent the range of results from five tests using 

different diets. Diet had at most a three-fold effect on the results, which is 

within the variation expected within the tests themselves. Therefore, results 

of different diets can be considered roughly equivalent to five replications of 

the same diet. This is a key study for chronic aquatic toxicity to invertebrates 

(see SIAR Table 12). 

 Reference: Taylor, M.J. 1985. Effect of diet on the sensitivity of Daphnia magna to 

linear alkylbenzene sulfonate. In: Cardwell, R.D., Purdy, R. and Bahner, 

R.C. Aquatic Toxicology and Hazard Assessment. Seventh Symposium pp. 

 53-72. ASTM STP 854, America Society for Testing and Materials, 

Philadelphia. 

 Reliability: 2 Valid with restrictions 

(f) 

 Type of test: static [ ]; semi-static [ X ]; flow-through [ ]; open-system [X]; closed-system 

[ ] 

 Species: Daphnia magna (Crustacea) 

 Endpoint: Mortality [ ]; Reproduction rate [X]; Other [ ]

 Exposure period: 21 day 

 Results: NOEC = 0.3 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: OECD Guide-line 202, part 2 “Daphnia sp., Reproduction Test 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS, with average chain length of C11.8 (CAS #68411-30-3) 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. Natural 

water 3x weekly renewal pH 6.0-8.5; 20+

/-2 oC; life-stage: 6-24 h. 

 Reference: European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 

 (g) 

 Type of test: static [ ]; semi-static [X]; flow-through [ ]; other [ ]; open-system [ ]; 

closed-system [ ] 

 Species: Daphnia magna (Crustacea) 

 Endpoint: Mortality [ ]; Reproduction rate [X]; Other [ ]
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 212

 Exposure period: 21 day 

 Results: NOEC = 0.3 mg/L 

 Analytical monitoring: Yes [ ] No [ ] ? [X]

 Method: UBA – draft protocol 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13, avg.: C11.6

 Remarks: Huels AG judged study quality to be good. Semistatic; pH 8.0; life-stage: 

adult. 

 Reference: European Commission. 2000d. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Huels AG, 2/87, N. 

Scholz, unpublished. 

 Reliability: 4 Not assignable. The original study was not available for review. 

 (h) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [ ]; closed-system 

[X]; not stated [ ] 

 Species: Paratanytarsus parthenogenica (Insecta, Midge) 

 Endpoint: Reproduction and survival 

 Exposure period: 28 days 

 Results: NOEC = 3.4 mg/L (from previous study) 

 NOEC = >2.0-<4.0 mg/L (from model ecosystem community study) 

 LOEC = 4.0 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: Initial experiments (Phase I) were designed to determine the effects of LAS 

on the structure and function of model ecosystem communities. Each test 

concentration consisted of duplicate 19-L glass aquaria containing 2.5 cm of 

natural lake sediment and several trophic levels (bacteria, algae, 

macrophytes, macroinvertebrates, and bluegill sunfish). Dilution water was 

carbon and reverse-osmosis filtered well water of 120 mg/L as CaCO3

hardness. Four nominal concentrations of 0.5, 1.0, 2.0, and 4.0 mg/L were 

delivered to duplicate chambers by a modified Mount and Brungs 

proportional diluter. Fish were screened from access to invertebrates with a 

stainless steel screen. In Phase II, conditions were similar except that the 

model ecosystem aquaria were treated with LAS in sewage effluent 

(supplied from a CAS unit) to more closely simulate actual receiving water 

conditions. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: C12 LAS 

 Remarks: Dissolved oxygen concentrations ranged between 7.0 to 9.0 mg/L with a 

mean of 7.8 mg/L during the Phase I studies. In Phase II, dissolved oxygen 

ranged between 3.1 and 7.3 mg/L (mean 5.4 mg/L), with the lowest values 

occurring in the chambers receiving the highest sewage effluent 

concentrations. Tempertures were maintained at 21 ± 2°C in both phases. 

The pH values were 8.1 ± 0.2 and 7.5 ± 0.3 for Phases I and II, respectively. 

No significant differences in the development and growth of midge 

populations was observed in Phase I. Apparent inhibition of total population 

size was observed at the highest concentration (4.0 mg/L), where total 

individuals were 4100 as compared to 6300 in the controls. The results 

indicate that the effect concentrations after 28 days were found to be between 

2.0 and 4.0 mg/L. This agrees with a previous 28-day study (Maki 1978) that 

resulted in a NOEC of 3.4 mg/L. 

 Reference: 1) Maki, A.W. 1981. A laboratory model ecosystem approach to 

environmental fate and effects studies. Procter & Gamble Company. 

 2) Maki, A.W. 1978. Development of a chronic toxicity test wit the dipteran 

midge, Paratanytarsus parthenogenica. Presented at the Annual Meeting of 

the Entomological Society of America, Washington, DC, December. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 213

 Reliability: 2 Valid with restrictions. 

 (i) 

 Type of test: static [X]; semi-static [ ]; flow-through [ ]; open-system [X]; closed-system [ 

]; not stated [ ] 

 Species: Brachionus calyciflorus (rotifer) 

 Endpoint: Reproduction and survival 

 Exposure period: 2 days 

 Results: EC10 = 1.18 mg/L 

 EC20 = 1.4 mg/L (95% confidence intervals 0.882-2.27 mg/L) 

 EC50 = 2.0 mg/L (95% confidence intervals 1.70-2.33 mg/L) 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: Chronic toxicity tests were performed by placing six newly hatched (less than 

3 h old), swimming rotifers in 10 mL of test water containing an equal 

mixture of green algae (a mixture of Selenastrum capricornutum and 

Chlorella vulgaris) at 1.0 x 106

 cells/mL as food. Three replicates were used 

for each concentration and control, with additional replicates used for 

analytical verification of the test compound as needed. Tests consisted of 

four to six concentrations and appropriate controls. Concentrations up to the 

limit of solubility were tested. All test vessels were placed on a rotator (1/5 

rpm) in a 16/8 h light:dark cycle under low light conditions at 25±2 °C. 

Dilution water was a 50/50 blend of locally obtained well water and 

deionized water and had mean water quality properties of pH 8.6, dissolved 

oxygen 8.5 mg/L, hardness 152 mg/L as CaCO3, and conductivity 450 

μmhos. Rotifers were counted after 48 h in all control and test concentration 

replicates. Since rotifers produce multiple broods in 48 hours, the endpoint 

for this study is effects on reproduction. The 48 h EC20 and EC50 values with 

associated 95% confidence intervals were estimated by an iterative nonlinear 

regression technique using SAS, version 6.0. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: C12.1 LAS, sodium salt; 92.3% purity 

 Remarks: LAS was one of about 20 surfactants tested in separate tests as part of this 

study. While test concentrations were measured, they were not reported in 

the publication. The authors do note that concentrations decreased by 20 to 

90% over the two-day test (depending on which surfactant was tested) and 

time-weighted averages exposure concentrations were used. NOEC or LOEC 

values were not reported. 

 Reference: Versteeg, D.J., Stanton, D.T., Pence, M.A., and Cowan, C. 1997. Effects of 

surfactants on the rotifer, Brachionus calyciflorus, in a chronic toxicity test 

and the development of QSARs. Environ. Toxicol. Chem. 16:1051-1058. 

 Reliability: 2 Valid with restrictions. Duration of test may be too short for a chronic 

study, therefore not included in SIAR Table 12A. 

 

 (j) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [X]; closed-system 

[ ] 

 Species: Campeloma decisum (freshwater mollusc; operculate snail) 

 Endpoint: Mortality [X]; Reproduction rate [ ]; Other [X] mobility and feeding 

responses 

 Exposure period: 6 weeks 

 Results: NOEC = 0.4 mg/L 

 LOEC = 1.0 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: Two 6-week chronic studies were performed in which an amphipod, a 

pulmonate snail, and an operculate snail were tested together. A serial 

diluter was used to provide continuous flow conditions into duplicate 4-
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 214

gallon glass aquaria for each of five concentrations plus controls. Ten snails 

were placed in each of two replicate chambers per concentration. The 

frequency of snails crawling on the test chamber walls was recorded 

throughout the tests. Mean measured LAS concentrations were 0.2, 0.4, 1.0, 

1.9, and 4.4 mg/L. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: Commercial LAS formulation containing 14% LAS, 2.3% alcohol ethoxylate 

oxide condensate, 2.5% sodium soap, 48% sodium tripolyphosphate, 9.7% 

sodium silicate, 15.4% sodium sulphate, and 8.1% moisture and 

miscellaneous. 

 Remarks: Survival of C. decisum was affected only in the highest test concentration 

(4.4 mg/L). Mobility and feeding responses were altered in LAS 

concentrations of 1.9 and 1.0 mg/L, respectively. 

 Reference: Arthur, J.W. 1970. Chronic effects on linear alkylbenzene sulfonate 

detergent on Gammarus pseudolimnaeus, Campeloma decisum and Physa 

integra. Water Res. 4:251-257. 

 Reliability: 4 Not assignable. Test substance is a formulation containing a mixture of 

materials, of which only 14% is LAS. The contribution of each component 

cannot be separately assigned. 

 (k) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [X]; closed-system 

[ ] 

 Species: Physa integra (freshwater mollusc; pulmonate snail) 

 Endpoint: Mortality [X]; Reproduction rate [ ]; Other [X] mobility and feeding 

response 

 Exposure period: 6 weeks 

 Results: NOEC = 4.4 mg/L 

 LOEC = >4.4 mg/L 

 Analytical monitoring: Yes [ ] No [X] ? [ ]

 Method: Two 6-week chronic studies were performed in which an amphipod, a 

pulmonate snail, and an operculate snail were tested together. A serial 

diluter was used to provide continuous flow conditions into duplicate 4-

gallon glass aquaria for each of five concentrations plus controls. The 

frequency of snails crawling on the test chamber walls was recorded 

throughout the tests. Mean measured LAS concentrations were 0.2, 0.4, 1.0, 

1.9, and 4.4 mg/L. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: Commercial LAS formulation containing 14% LAS, 2.3% alcohol ethoxylate 

oxide condensate, 2.5% sodium soap, 48% sodium tripolyphosphate, 9.7% 

sodium silicate, 15.4% sodium sulphate, and 8.1% moisture and 

miscellaneous. 

 Remarks: No significant effects on survival, mobility, or feeding responses was 

observed in P. integra at any LAS concentration tested. 

 Reference: Arthur, J.W. 1970. Chronic effects on linear alkylbenzene sulfonate 

detergent on Gammarus pseudolimnaeus, Campeloma decisum and Physa 

integra. Water Res. 4:251-257. 

 Reliability: 4 Not assignable. Test substance is a formulation containing a mixture of 

materials, of which only 14% is LAS. The contribution of each component 

cannot be separately assigned. 

 (l) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [X]; closed-system 

[ ] 

 Species: Gammarus pseudolimnaeus (freshwater amphipod) 
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UNEP PUBLICATIONS 215

 Endpoint: Mortality [X]; Reproduction rate [ ]; Other [X] mobility and feeding 

responses 

 Exposure period: 6 weeks 

 Results: For adult survival: NOEC = 0.2 mg/L, LOEC = 0.4 mg/L 

 For reproduction: NOEC < 0.2 mg/L, LOEC = 0.2 mg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ]

 Method: Two 6-week chronic studies were performed in which an amphipod, a 

pulmonate snail, and an operculate snail were tested together. A serial 

diluter was used to provide continuous flow conditions into duplicate 4-

gallon glass aquaria for each of five concentrations plus controls. Ten snails 

were placed in each of two replicate chambers per concentration. Complete 

immobilization was taken as a sign of death for the amphipods. Mean 

measured LAS concentrations were 0.2, 0.4, 1.0, 1.9, and 4.4 mg/L. Only 

adult amphipods were started in each 6-week test. Following the termination 

of the second 6-week test, however, the newly hatched Gammarus were 

counted and allowed to remain in each respective test chamber for 15 weeks 

of additional exposure. 

 GLP: Yes [ ] No [X] ? [ ] 

 Test substance: Commercial LAS formulation containing 14% LAS, 2.3% alcohol ethoxylate 

oxide condensate, 2.5% sodium soap, 48% sodium tripolyphosphate, 9.7% 

sodium silicate, 15.4% sodium sulphate, and 8.1% moisture and 

miscellaneous. 

 Remarks: Adult survival was affected at all concentrations after 6-weeks in a somewhat 

dose-responsive manner, as shown in the following table. Based on adult 

survival, the NOEC is 0.2 mg/L and the LOEC is 0.4 mg/L. 

 

Mean LAS 

Concentration 

(mg/L) 

Duplicate 

Chambers Trial 1 Trial 2 

4.4 A 

B 

0 

0 

0 

0 

1.9 A 

B 

10 

10 

0 

0 

1.0 A 

B 

40 

30 

20 

30 

0.4 A 

B 

30 

40 

20 

40 

0.2 A 

B 

70 

40 

50 

50 

Control A 

B 

80 

70 

60 

40 

 Newly hatched amphipods were not produced in the highest concentration 

(4.4 mg/L). The results on survival of F1 Gammarus from the second 6-week 

study, and the final numbers of gravid F1 females and F2 young produced 

after 15 weeks of exposure are shown below. Control F1 females were the 

first to release F2 young, and this occurred after 9 weeks. Females began 

liberation of F2 young at 13 and 13.5 weeks for the 0.2 and 0.4 mg/L 

chambers, respectively. Based on variability and apparent reproductive 

effects at the lowest concetration, no NOEC value could be determined. The 

LOEC is 0.2 mg/L. 

 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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Final F1 numbers F1 Females Mean LAS 

concentration 

(mg/L) 

Duplicate 

Chambers 

F1 Initial 

young 

numbers Males Females % 

Survival

Final 

number 

gravid 

Number 

of births 

Number 

F2

produced

4.4 A 

B 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

1.9 A 

B 

4 

9 

3 

3 

0 

3 

75 

66 

0 

0 

0 

0 

0 

0 

1.0 A 

B 

32 

37 

3 

10 

4 

16 

22 

70 

1 

3 

0 

0 

0 

0 

0.4 A 

B 

29 

59 

8 

25 

7 

24 

52 

83 

2 

4 

0 

1 

0 

32 

0.2 A 

B 

52 

58 

11 

11 

9 

16 

38 

47 

8 

11 

2 

3 

45 

48 

Control A 

B 

77 

91 

26 

19 

22 

31 

62 

55 

5 

17 

6 

5 

109 

74 

 Reference: Arthur, J.W. 1970. Chronic effects on linear alkylbenzene sulfonate 

detergent on Gammarus pseudolimnaeus, Campeloma decisum and Physa 

integra. Water Res. 4:251-257. 

 Reliability: 4 Not assignable. Test substance is a formulation containing a mixture of 

materials, of which only 14% is LAS. The contribution of each component 

cannot be separately assigned. 

 

 (m) 

 Species: Mysidopsis bahia (marine mysid) 

 Results: NOEC = 0.12 mg/L (2 records) 

 Test Substance: LAS normalized to C11.6

 Remarks: NOEC is geometric mean of 2 records 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J. and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: LAS, AE, AES, and soap, 

Environ. Toxicol. Chem. 18:2653-2663. 

 Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

 (n) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; other [ ]; open-system [X]; 

closed-system [ ] 

 Species: Gammarus pulex (amphipod) 

 Endpoint: Mortality [X]; Reproduction rate [X]; Other [ ] 

 Exposure period: Adults = 8 weeks; Juveniles = 15 weeks 

 Results: LC50 (adults; 56 days) > 354 μg/L 

 LC50 (juveniles; 107 days) > 375 μg/L 

 NOEC (number of offspring) = 97 μg/L 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: Two separate groups of field-collected adults in the pre-copulatory amplexus 

and early juveniles were exposed to five concentration of LAS (nominally 

30, 60, 120, 240, 480 μg/L) and control under flow-through conditions. The 

exposure vessel consisted of a plastic trough that was 40 cm by 10 cm. The 

water depth was approximately 3 cm with standpipe to drain and a 2 μm 

stainless steel piece of mesh was placed approximately 5 cm from the end of 

the vessel to prevent the loss of Gammarus. The solution was made up of a 

1:1 mixture of pond water and carbon-filtered tap water. Mean measured 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 217

concentrations for adult exposure were <1, 19, 35, 83, 176, 354 μg/L and for 

juvenile exposure were <1, 22, 36, 97, 141 and 375 μg/L. Survival and 

reproduction were recorded over an 8 week exposure for adults and a 15 

weeks of exposure for juveniles. Offspring produced during the exposure 

were counted weekly but not removed from the test areas. 

 GLP: Yes [X] No [ ] ? [ ] 

 Test substance: Commercial LAS, C10-14 Sodium alkyl benzene sulfonate (CAS# 85117-50-

6); Alkyl chain distribution: C10 10.3%, C11 34.6%, C12 32.7%, C13 21.6%, 

C14 0.9%; Average chain length 11.7. 

 Remarks: This study is considered invalid due to high control mortality, which was 

23% and 37% for adult and juvenile exposures, respectively. Mortality of 

adults and juveniles exposed to test materials was in the same range, 

indicating that survival was not affected by exposure to LAS. Although the 

reproductive output at the highest two concentrations was lower than that in 

the lowest concentrations, it was not possible to conclude that this was due to 

LAS because the control reproduction was also lower. There was no 

significant difference in cumulative number of juvenile produced between the 

control and the highest concentration tested (354 μg/L). For the juveniles, 

the time of formation of pre-copular pairs was slower at the highest 

concentration tested, 375 μg/L. By day 86, the number of offspring produced 

at 141 and 375 μg/L was significantly lower than produced at the other LAS 

concentrations and control. The NOEC remained at 97 μg/L until the end of 

the study (day 107). 

 Reference: ERASM. 2000. Long-term toxicity of LAS on Gammarus pulex. Internal 

Report AISE/CESIO, Brussels. 

 Reliability: 3 Not valid due to excessive control mortality. 

 (o) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [ ]; closed-system 

[X]; not stated [ ] 

 Species: Chironomus riparius (Insecta, Midge) 

 Endpoint: Survival and emergence 

 Exposure period: Approximately 24 day 

 Results: NOEC = 2.4 mg/L in water w/o sediment 

 LOEC = 3.72 mg/L in water w/o sediment 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: Tests were conducted as an aqueous fraction in the absence of sediment. A 

flow-through diluter system delivered test material in water to glass 

containers with 120-140 cm2

 bottom surface area each. Intact egg masses 

were incubated in Petri dishes containing 20-30 mL of dilution water at 22 

°C until hatching commenced. Newly hatched larvae were allowed to 

mature 72 hours before testing. Twenty larvae were randomly distributed to 

each duplicate test chamber for each of five test concentrations plus the 

controls. Larvae were fed daily until emergence of the first adult in each 

chamber. Tests were continued until each midge emerged as an adult or 

larvae were determined to be dead. The number of winged adults was 

recorded daily. The average test duration was 24 days. Total hardness, pH, 

dissolved oxygen, and temperature were monitored frequently during the 

test. 

 GLP: Yes [ ] No [] ? [X] 

 Test substance: C11.8 LAS; 30.4% activity; mean molecular weight = 346 

 Remarks: Adults typically emerged 12-14 days after hatching. Control values for adult 

emergence were similar to or exceeded the historical average observed in 

their laboratory (>90%). For comparison, additional flow-through studies 

were conducted with sediment from a naturally unspiked stream and using 

spiked sediments (see 4.5.2 (v)). The study with spiked sediments resulted in 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 218

a NOEC of 319.0 ppm (LOEC = 993 ppm). This indicates that sorption onto 

sediment significantly mitigates LAS bioavailability. Thus, the water-only 

values above should be considered conservative. This is a critical study for 

this SIDS endpoint. 

 Reference: Pittinger, C.A., Woltering, D.M., and Masters, J.A. 1989. Bioavailability of 

sediment-sorbed and aqueous surfactants to Chironomus riparius (midge). 

Environ. Toxicol. Chem. 8:1023-1033. 

 Reliability: 2 Valid with restrictions. 

Water and Sediment Exposures 

 (p) 

 Type of Test: Semi-static 

 Species: Anodonta cygnea (fresh water bivalve mollusc) 

 Endpoint: Mortality [X]; Reproduction rate [ ]; Other [ ] growth, reproduction 

 Exposure period: 80 days 

 Results: NOEC ≥ 200 mg/kg dw 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

Method: Sediments were collected from a pond and LAS was sorbed to sediment by 

repeated additions for 80 days. Glass tanks containing a 4 cm thick layer of 

spiked sediment and eight liters of dechlorinated tap water were used. A 

continuous water exchange allowed for a whole water mass change every 24 

hours. Ten bivalves (10+

/-1 cm or larger diameter) were introduced into each 

tank. The LAS sorbed to sediment was 750 mg/kg dw at the beginning of 

the experiment and 200 mg/kg dw at the end of the experiment. 

 GLP: Yes [ ] No [ ] ? [X] 

 Test Substance: Commercial LAS (unspecified) 

 Remarks: All animals survived the 80 day exposures and were actively filter-feeding 

without differences from the controls. 

 Reference: Bressan, M., Brunetti, R., Casellato, S., Fava, G.C., Giro, P., Marin, M., 

Negrisolo, P., Tallandini, L., Thomann, S., Tosoni, L., Turchetto, M. and 

Campesan, G.C. 1989. Effects of linear alkylbenzene sulfonate (LAS) on 

benthic organisms. Tenside Surf. Det. 26:148-158. 

 Reliability: 2 Valid with restrictions (no GLP, statistical methods not described) 

 (q) 

 Type : Artificial soil [ ]; Filter paper [ ]; Other [X] Natural sediment

 Species: Branchiura sowerbyi (tubificid worm)

 Endpoint: Mortality [ ]; Weight [ ]; Other [X] Reproductive Cycle

 Exposure period: 220 days 

 Results: NOEC ≥ 7.18 mg/kg. 

 Mean measured LAS concentrations in the sediment were 26, 9.8, and 7.18 

mg/kg at 0, 45, and 220 days of exposure. No significant differences were 

observed between treated and control sediments for any parameter (survival, 

timing and percentage of cocoons, percent of hatching worms, number of 

eggs per cocoon, and mean embryonic development time). Total number of 

cocoons was slightly higher in treated worms than cocoons. 

 Method: Twenty specimens in duplicate were used for both the control and treated 

sediments for testing the possible effects of a long exposure to LAS adsorbed 

on sediment to oligochaetes. Worms with a well known reproductive cycle 

were collected and maintained in the dark at 15oC in a glass container with 

natural sediment for at least two weeks before the experiment. The sediment 

for the experiments was gently washed with deionized water and dried at 

70oC. It was organized by grain size, carbonate and organic carbon contents. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 219

It was then treated in order to obtain the irreversibly adsorbed concentration 

of LAS. 

 The test substance and sediment mixture were equilibrated for 6 hours on a 

rotary shaker and then allowed to settle for 48 hours. Twenty eight washes 

were made with deionized water to ensure the sediment did not release any 

methylene blue material to the overlaying water. The residual concentration 

was checked after every wash in the overlaying water of desorbed LAS using 

the MBAS method. When an ~0 was observed, it was considered that the 

irreversibly adsorbed quantity of LAS in sediment was attained. This 

sediment was used in the experiment. The concentration of LAS in sediment 

was measured by HPLC at 0, 45, and 220 days. Endpoints measured 

included the number of cocoons, number of oocytes per cocoon, total 

number of oocytes, period of embryonic development, percent of 

degenerated cocoons, and percent of hatching worms. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS solution (1000 mg/kg) mixed with 200 g dried sediment (from EniChem 

Augusta Industriale S.A.) 

 Remarks: The LAS concentration in sediment used did not produce any effect on B. 

sowerbyi during the 220 days of exposure. The authors conclude that LAS 

absorbed on sediment has a much lower influence on the examined worms 

than LAS dissolved in water. The intitial concentration of LAS in treated 

sediments was 25.87 mg/kg (3.99 mg/kg in control). After 45 days, a 

reduction of 62-63% of the nominal concentration was measured. After 220 

days, the reduction reached 72%. 

 Reference: Casellato, S., Aiello, R., Negrisolo, P.A., and Seno, M. 1992. Long-term 

experiment on Branchiura sowerbyi Beddard (Oligochaeta, Tubificidae) 

using sediment treated with LAS (Linear Alkylbenzene Sulphonate). 

Hydrobiologia 232:169-173. 

 Reliability: 4 Not assignable. Documentation is incomplete, including identification of 

the structure, description of methods, lack of statistics, etc. 

 (r) 

 Type : Artificial soil [ ]; Filter paper [ ]; Other [X] Spiked Sediment

 Species: Lumbriculus variegatus (Oligochaete) 

 Endpoint: Mortality [ ]; Weight [ ]; Other [X] Survival, Reproduction, and Growth

 Exposure period: 28 days 

 Results: LC50 (28 d) ≥ 105 mg/kg soil dry weight (see table) 

 NOEC = 81 mg/kg soil dry weight 

 Method: A 28 day chronic study was conducted using sediment spiked with radiolabelled material. The test species, Lumbriculus variegatus, is a true 

sediment feeder (i.e., subsurface ingestion of sediment particles). The 

nominal concentrations were 50, 75, 100, 150, 300, 600 mg/kg/dry weight 

and controls. The test sediment contained 44% sand, 48% silt, and 8% 

clay. Twenty grams (wet weight) of the prepared sediment was added to 

clean 60 mL glass vessels followed by 30 mL of groundwater drawn from 

an aquifer. After 24 hours of equilibration, 10 mature Lumbriculus (ca. 15 

mm in length, 8 mg dry weight) were added to each vessel. Vessels were 

aerated for 5 minutes every day and the overlying water replenished with 

distilled water every two days. Each test concentration was replicated 6 

times. LAS concentrations were measured at 0 and 28 days. After 28 days 

the sediment was removed and all live worms counted, blotted dry, and wet 

weighed prior to air drying for 48 hours to a constant dry weight. Toxicity 

endpoints included survival, reproduction and biomass. The mode of 

reproduction (architomy) necessitates the treatment of survival and 

reproduction as a single endpoint, i.e., number of organisms at test 
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termination. Sediment concentrations were monitored using LSC and 

verified with HPLC. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: LAS (Procter & Gamble), average alkyl chain length C11.4. The radiolabelled LAS was 3-dodecylbenzene sulfonate (DOBS; 95% purity) 

 Results: There was a loss of between 15 and 78% of the LAS radioactivity over the 

duration of the test, which was attributed to mineralization of LAS by the 

worms and microorganisms present in the sediment (biodegradation). 

Results are therefore based on the average of day 0 and day 28 measured 

sediment concentrations. All results are shown in the following table. 

 

 Sediment Concentration (mg/kg dw) 

Survival Endpoint NOEC LOEC EC20 EC50

Based on nominal values 100 150 90 136 

Based on measured day 0 values 136 170 131 164 

Based on mean of days 0 & 28 values 81 110 73 105 

Biomass Endpoint 

Based on nominal values 100 150 108 144 

Based on measured day 0 values 136 170 146 166 

Based on mean of days 0 & 28 values 82 110 102 109 

 Remarks: LAS half-life in aerobic sediment was approximately 20 days. This is 

shorter than studies conducted in the same sediment without worms (halflife of 38 days), most likely due to increased bioturbation due to worm 

activity. No specific endpoint was particularly sensitive to LAS. 

 Reference: Comber, S.D.W., Conrad, A.U., Hurst, K., Hoss, S., Webb, S., and Marshall, 

S. 2004. Chronic toxicity of sediment-associated linear alkylbenzene 

sulphonates (LAS) to freshwater benthic organisms. Manuscript in 

preparation. 

 Reliability: 2 Valid with restrictions 

 

 (s) 

 Type : Artificial soil [ ]; Filter paper [ ]; Other [X] Spiked Sediment

 Species: Caenorhabditis elegans (Nematode) 

 Endpoint: Mortality [ ]; Weight [ ]; Other [X] Survival, Fertility, Egg Production

 Exposure period: 3 days 

 Results: LC50 (3 d) > 100 mg/kg soil dry weight 

 NOEC = 100 mg/kg soil dry weight (egg production) 

 Method: A 3 day chronic study was conducted using sediment spiked with coldmaterial LAS. Nominal concentrations were in the range of 10 to 1,000 

mg/kg/dw. The test species is an infaunal bacterial feeder with a short life 

cycle, so 72 hours (3 days) is considered a chronic test. The nominal 

concentrations were 50, 75, 100, 150, 300, 600 mg/kg/dry weight and 

controls. The test sediment contained 44% sand, 48% silt, and 8% clay, 

with 2% organic matter. At the start of the test, ten juvenile worms of the 

first stage (270 ± 16 μm body length) were transferred to each test vial 

containing 0.75 g wet weight of spiked sediment mixed with 0.25 mL of a 

bacterial suspension. Five replicates were set up for each treatment, and the 

samples were incubated on a shaker at 20°C. After 72 hours the test was 

stopped by heat-killing the worms at approximately 50°C. The samples 

were mixed with an aqueous solution of rose Bengal to stain the worms for 

easier recovery. Sublethal toxicity endpoints were determined for growth 

based on the body length of the organisms, and fecundity by counting the 

number of eggs in the body of the test organism (egg production). The test 

was regarded as valid as the fertility of the test organisms in the control was 

≥ 80%. 
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 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (Procter and Gamble), average alkyl chain length C11.4. 

 Results: Results are shown in the following table. 

 Nominal Sediment Concentration (mg/kg dw) 

Test Parameter NOEC LOEC EC10 EC30

Growth 200 300 275 

Fertility 200 300 258 

Egg Production 100 200 125 

 Remarks: For growth, with a low variability, an EC10 was chosen, whereas it was more 

appropriate to use an EC30 for the more variable parameters fertility and egg 

production. Egg production was the most sensitive endpoint. Toxicity 

values might be underestimated slightly, as threshold values were calculated 

using nominal concentrations (chemical analysis was only performed for 

selected test concentrations). The chemical analysis at the end of the test 

showed values 73 to 80% of the initial, nominal concentrations, which 

equates to mean exposure concentrations of 87 to 90% for the nematodes 

during the test. 

 Reference: Comber, S.D.W., Conrad, A.U., Hurst, K., Hoss, S., Webb, S., and Marshall, 

S. 2004. Chronic toxicity of sediment-associated linear alkylbenzene 

sulphonates (LAS) to freshwater benthic organisms. Manuscript in 

preparation. 

 Reliability: 2 Valid with restrictions 

 (t) 

 Type of test: Various types and durations of tests 

 Results: The two articles compile the no observed effect concentration (NOEC) 

values for many tests conducted on an assortment of marine species. The 

following table shows the geometric mean NOEC values for each species for 

marine invertebrates, as well as one fish and two algae species. 

Genus (and species) Geometric mean NOEC 

(mg/L) 

Limanda (yokohamae) 0.05 

Arbacia 0.45 

Chaetopterus 0.45 

Asterias 0.35 

Mysidopsis (bahia) 0.12 

Mysidopsis 0.20 

Crassostrea (virginica) 0.025 

Crassostrea 0.04 

Mytilus (edulis) 0.025 

Mytilus 0.04 

Arcatia 0.30 

Botrylloides 1.94 

Molgula 0.90 

Spisula 0.80 

Botryllus 0.75 

Laminaria 5.00 

Dunaliella 0.11 

 
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 Remarks: All data were from tests conducted on commercial LAS with C10-13 alkyl 

chains and average carbon lengths of C11.6 and C11.8. The NOEC values have 

been normalized using QSARs to the average structure of C11.6 LAS. 

 Reference: 1) Temara, A., Carr, G., Webb, S., Versteeg, D. and Feijtel, T. 2001. Marine 

risk assessment: Linear alkylbenzenesulphonates (LAS) in the North Sea. 

Marine Pollution Bulletin 42:635-642. 

 2) van de Plassche, E.J., DeBruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J., and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: Linear alkyl benzene sulfonate, 

alcohol ethoxylates, alcohol ethoxylated sulfates, and soap. Environ. 

Toxicol. Chem. 18: 2653-2663. 

 Reliability: 4 Not assignable. This study was given a reliability score of 4 because the 

original reports reviewed by the authors were not directly reviewed in the 

compilation of this robust summary. 

 (u) 

 Type: static [ ]; semi-static [X]; flow-through [ ]; other [ ]; open-system [ ]; 

closed-system [ ]

 Species: Mytilus galloprovincialis (marine mussel) 

 Endpoints: Other. filtration rate, oxygen uptake, nitrogen excretion 

 Exposure period: 7 days 

 Results: NOEC = 32.19 mg/kg dry weight (geometric mean of initial [132 mg/L] and 

final [7.85 mg/L] LAS concentration) 

 Analytical Monitoring: Yes 

 Method: Thirty mussels (5.8 cm average main axis length) collected from a mussel 

cultivation area of the Lagoon of Venice, Italy were divided into groups of 10 

and placed in net tubes in a 60-L tank for 7 days in contact with 50 mg/L 

continuously suspended LAS-spiked sediments. Mussels were fed an algal 

suspension and water, food, and sediment were renewed daily. Filtration rate 

was determined twice a day (immediately before and after water changes) as 

defined by the volume of water cleared of algal particles/animal/hour. Faeces 

were collected daily and pooled for analysis of LAS concentrations by 

HPLC. Oxygen consumption and ammonia excretion rates were determined 

at the end of each treatment. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Commercial LAS; likely average alkyl chain length = C11.6

 Remarks: No significant differences in survival or physiological responses between 

treatments and controls were observed. The LAS concentration in treated 

sediments decreased by about 90% over the duration of the study (mean 132 

mg/kg at initiation to mean 7.85 mg/kg at completion). 

 Reference: Marin, M.G., Pivotti, L., Campesan, G., Turchetto, M. and Tallandini, L. 

1994. Effects and fate of sediment-sorbed linear alkylbenzene sulphonate 

(LAS) on the bivalve mollusk Mytilus galloprovincialis Lmk. Wat. Res. 

28:85-90. 

 Reliability: 2 Valid with restrictions 

 (v) 

 Type of test: static [ ]; semi-static [ ]; flow-through [X]; open-system [ ]; closed-system 

[X]; not stated [ ] 

 Species: Chironomus riparius (Insecta, Midge) 

 Endpoint: Emergence 

 Exposure period: Approximately 24 day 

 Results: NOEC = 319 ppm in sediment 

 LOEC = 993 ppm in sediment 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 
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 Method: Tests were conducted as an aqueous fraction in the presence of sediment. 

Natural stream sediments (71% clay, 19% fine silt, 4% medium sand, 6% 

fine sand) were collected from a pristine site in Rapid Creek, SD. Before 

testing, wet sediment was autoclaved for 40-60 minutes to reduce microbial 

populations and minimize initial rates of surfactant biodegradation. LAS was 

added to a sediment slurry at a nominal concentration and stirred overnight, 

then 350 g was poured into each test chamber and allowed to settle. The 

organic carbon content of the test sediment was 4.2% prior to testing. A 

flow-through diluter system delivered test material in water to glass 

containers with 120-140 cm2

 bottom surface area each. Test concentrations 

were control, 8, 42, 146, 319, and 993 ppm. Intact egg masses were 

incubated in Petri dishes containing 20-30 mL of dilution water at 22 °C 

until hatching commenced. Newly hatched larvae were allowed to mature 

72 hours before testing. Twenty larvae were randomly distributed to each 

duplicate test chamber for each of five test concentrations plus the controls. 

Larvae were fed daily until emergence of the first adult in each chamber. 

Tests were continued until each midge emerged as an adult or larvae were 

determined to be dead. The number of winged adults was recorded daily. 

The average test duration was 24 days. Total hardness, pH, dissolved 

oxygen, and temperature were monitored frequently during the test. 

 GLP: Yes [ ] No [] ? [X] 

 Test substance: C11.8 LAS; 30.4% activity; mean molecular weight = 346 

 Remarks: Adults typically emerged 12-14 days after hatching. Control values for adult 

emergence were similar to or exceeded the historical average observed in 

their laboratory (>90%). Percent emergence was 98, 95, 90, 90, 90, and 73 

for the control, 8, 42, 146, 319, and 993 ppm concentrations, respectively. 

For comparison, additional flow-through studies were conducted without 

sediment (see 4.5.2 (o)). Results indicate that sorption onto sediment 

significantly mitigates LAS bioavailability. 

 Reference: Pittinger, C.A., Woltering, D.M., and Masters, J.A. 1989. Bioavailability of 

sediment-sorbed and aqueous surfactants to Chironomus riparius (midge). 

Environ. Toxicol. Chem. 8:1023-1033. 

 Reliability: 2 Valid with restrictions. 

4.6 TOXICITY TO TERRESTRIAL ORGANISMS 

4.6.1 TOXICITY TO SOIL DWELLING ORGANISMS 

(a) 

Species/Endpoints: See table 

Results: The following table shows the available NOEC, EC10 and EC50 values for 

eleven soil dwelling invertebrate species (in mg/kg dry weight). 

 

Species Endpoint NOEC EC10 EC50

Eisenia foetida Reproduction 383 558 

Lumbricus terrestris Weight 667 

Aporrectodea caliginosa Reproduction 14 129 

Aporrectodea longa Reproduction 27 137 

Folsomia fimetaria Reproduction 96 442 

Folsomia candida Reproduction 18 91 

Hypoaspis aculeifer Reproduction 81.7 236 

Enchytraeus albidus Reproduction 6.2 40.5 

Platynothrus peltifer Reproduction 320 467 

Isotoma viridis Growth 41 
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Species Endpoint NOEC EC10 EC50

Hypogastrura assimilis Reproduction 99.8 421 

Test Substance: LAS (unspecified) 

Remarks: Values were extracted from a variety of original references and compiled for 

this article. 

Reference: Jensen, J., Lokke, H., Holmstrup, M., Krogh, P.H. and Elsgaard, L. 2001. 

Effects and risk assessment of linear alkylbenzene sulfonates in agriculture 

soil. 5. Probabilistic risk assessment of linear alkylbenzene sulfonates in 

sludge-amended soils. Environ. Toxicol. Chem. 20:1690-1697. 

Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

(b) 

 Type : Artificial soil [ ]; Filter paper [ ]; Other [X] Sandy, agricultural soil

 Species: Enchytraeus albidus, Aporrectodea caliginosa, Aporrectodea longa, 

Folsomia fimetaria, Hypogastrura assimilis, and Hypoaspis aculeifer

 Endpoint: Mortality [X]; Weight [X]; Other [X] Reproduction

 Exposure period: 21 days (28 days for A. caliginosa and A. longa growth tests) 

 Results: The following table shows the results of all tests. All values are nominal 

LAS concentrations in mg/kg dry weight. 

Species Parameter NOEC LOEC 

LC10 

or 

EC10

LC50

or 

EC50

Reliability 

Rating 

Rationale for 

Reliability Rating 

Enchytraeus 

albidus

Survival, adults 

Reproduction 

198 

20 

397 

40 

194 

6 

430 

41 

1 

1 

Draft ISO/WD 16387 

protocol 

Aporrectodea 

caliginosa

Survival, adults 

Cocoon production 

Survival, juveniles 

Growth, juveniles

278 

>793 

>397 

278 

793 

>793 

>397 

397 

329 

14 

>397 

105 

535 

129 

>397 

354 

2 

3 

2 

2 

Comparable to 

ISO 11268-2 

Deviations; limited 

cocoons 

Comparable to ISO 11268-

2, but with only weight 

measurement

Aporrectodea 

longa

Survival, adults 

Cocoon production 

Survival, juveniles 

Growth, juveniles

278 

>793 

397 

79 

793 

>793 

793 

278 

329 

27 

296 

84 

535 

137 

517 

349 

2 

3 

2 

2 

Comparable to 

 ISO 11268-2 

Deviations; limited 

cocoons 

Comparable to ISO 11268-

2, but with only weight 

measurement

Folsomia 

fimetaria

Survival, adults 

Reproduction 

>793 

278 

>793 

278 

>793 

85 

>793 

424 

1 

1 

Comparable to ISO 

11267 

Hypogastrur

a assimilis Reproduction 79 278 99 421 1 Comparable to ISO 

11267 

Hypoaspis 

aculeifer

Survival, adults 

Reproduction 

>793 

278 

>793 

793 

>793 

82 

>793 

236 

2 

2 No guideline available 

 Method: The effect of LAS on six species of soil invertebrates was determined using 

the following methods. 

 Earthworm tests: 

 No internationally accepted guideline is available for A. caliginosa and A. 

longa. For the reproduction tests, 1 kg dry weight of soil was carefully 

mixed with 160 mL of LAS solution using an electric mixer and filled into 

plastic pots. The six treatments consisted of one control and five 

concentrations of LAS and these treatments were randomly assigned to the 

experimental units. After 24-hour equilibration of the test soil, 3 (rather than 
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UNEP PUBLICATIONS 225

10) earthworms were added to closed containers with perforated lids for 

ventilation. Approximately 5 g per worm were added after the test animals 

had been introduced. The containers were then incubated for 21 days in 

darkness and the contents were later wet sieved through a 1-mm mesh. 

Water content was adjusted after 14 days. 

 For the growth test with juvenile A. caliginosa (2-3 weeks old), 60 g dry 

weight of soil were mixed with 9.6 mL of LAS solution with a spatula and 

filled into 160-mL polyethylene beakers with perforated lids for ventilation. 

The six treatments consisted of one control and five concentrations of LAS 

and these treatments were randomly assigned to the experimental units. After 

24-hour equilibration of the test soil, one earthworm was added to each 

container. The beakers were incubated for 28 days in darkness and then the 

earthworms were recovered and their guts were cleared. The surviving 

animals were dried for 24 hours and their dry weight was recorded to the 

nearest 0.1 mg. The examination of the effects on growth of A. longa used 

the same method except the test period was 42 days. 

 Enchytraeid test: 

 The enchytraeid reproduction test followed a previously described protocol 

(draft ISO/WD 16387) using the potworm (Enchytraeus albidus). Forty 

grams dry weight of soil were mixed with 6.4 mL of LAS solution and filled 

into 160-mL beakers with perforated lids for ventilation. After 24-hour 

equilibration of the test soil, 10 adult E. albidus were added to each container 

and incubated in darkness for 21 days. After incubation, the surviving adult 

animals were removed from the soil. Now only containing cocoons, the soil 

was incubated in the beakers for another 21 days to allow development and 

hatching of the juveniles. After this period, the soil containing juveniles was 

stained with Bengal red, and water was added to facilitate counting of the 

juveniles. The test concentrations were not provided but can be estimated 

from Figure 5 to be 0, 20, 40, 80, 200 and 400 mg/kg with the numbers of 

adults surviving per replicate to be approximately 10, 10, 10, 10, 9, and 6, 

and the numbers of juveniles per replicate (reproduction) to be approximately 

77, 50, 37, 21, 0, and 0, respectively. 

 Springtail tests: 

 No internationally accepted guideline is available for springtail reproduction. 

Effects of reproduction of F. fimetaria were determined using a method 

described by Wiles and Krogh. Twenty-seven grams dry weight of soil were 

mixed with 3 mL of LAS solution and filled into cylindrical test containers 

with lids. The bottom of the cylinder consisting of a 1-mm mesh to allow 

later extraction of the test animals. The mesh was covered with a layer of 

plastic film to prevent escape of the test animals. Adult, rather than juvenile, 

springtails were used. Ten male and ten female F. fimetaria (23-26 days old) 

were added to the test containers after 24-hour equilibration of the test soil. 

The containers were incubated for 21 days with 12:12 photoperiod (h). after 

incubation, the animals were extracted using MacFadyen high-gradient 

extraction and the number of offspring counted. The same procedure was 

used for the springtail species H. assimilis Krausbauer, using ten male and 

ten female adults (16-19 days old). The test concentrations were not listed 

but can be estimated from Figure 6 to be 0, 10, 25, 75, 275, and 800, with the 

numbers of adult surviving per replicate to be approximately 145, 155, 115, 

110, 165, and 165 and the numbers of juveniles per replicate (reproduction) 

to be approximately 285, 275, 190, 145, 205, and 10. 

 Predacious mite test: 

 No internationally accepted guideline is available for mite reproduction. 

Effects on reproduction on the predacious mite (H. aculeifer) were examined 

according to a method described by Krogh and Axelsen. A total of 54 g dry 

weight of soil was mixed with 6 mL of LAS solution and filled into test 
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containers (as described for springtails). Ten female and five male H. 

aculeifer (16-19 days old) were added to each test container together with 

100 F. fimetaria (16-19 days old) serving as prey for the mites. Incubation 

and extraction of mite offspring followed the same procedure as described for 

springtails. 

 A natural sandy, agricultural soil was used for all tests, rather than synthetic 

test soil. Nominal concentrations of LAS for some tests were verified by 

chemical analysis using HPLC. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS was obtained as an aqueous sodium salt solution with an active 

matter concentration of 16.1% (w/w), average molecular weight = 342 g/mol, 

distribution of the linear alkyl chains: C10 14%, C11 34%, C12 31%, and C13

21%; average alkyl chain length = C11.6

 Remarks: Toxic effects on reproduction and growth were revealed when the 

concentration in soil exceeded 40 to 60 mg/kg dry weight. Reproduction was 

approximately fourfold more sensitive in earthworms and enchytraeids than 

in springtails and mites. It is argued that this difference in sensitivity is 

related to the dependency of soil pore water, which is high in the annelids but 

comparatively low in the arthropods. It should be noted that these studies 

report worst case exposures due to the use of a sandy test soil and the fact 

that LAS was added as an aqueous solution to the soil. In addition, too few 

replicates were used for the ECx approach (e.g., <5 controls) and several key 

deviations from draft protocols limited the reliability of endpoints for some 

studies (e.g., A. caliginosa and A. longa cocoon production). Nominal 

concentrations were derived from tables and figures since actual values were 

not found in the text. 

 Reference: Holmstrup, M. and Krogh, P.H. 2001. Effects and risk assessment of linear 

alkylbenzene sulfonates in agricultural soil. 3. Sublethal effects on soil 

invertebrates. Environmental Toxicology and Chemistry 20:1673-1679. 

 Reliability: See table for reliability of individual endpoints by species. 

(c) 

 Type : Artificial soil [X]; Filter paper [ ]; Other [ ]

 Species: Eisenia foetida (Worm (Annelida), soil dwelling). 

 Endpoint: Mortality [X]; Weight [X]; Other [ ]

 Exposure period: 14 day 

 Results: LC50 >1000 mg/kg 

 NOEC = 250 mg/kg soil dw 

 Method: OECD Guideline 207, 1984. Ten adult worms (mean wt. 0.66 g/animal) 

were placed into each of four glass jars per concentration with soil comprised 

of 70% 5010 grade silica sand, 20% kaolinite clay, and 10% finely ground 

sphagnum peat. Nominal test concentrations in the soil were 1000, 500, 250, 

125, 63 and 0 mg/kg dry weight. Temperature was maintained at 20+

/-2oC 

with 24-hour continuous lighting at 600 lux. Earthworms were assessed for 

mortality, general health, body weight, and behavior after 7 and 14 days. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (commercial blend) with average alkyl chain length C11.6 (typical of 

LAS chain lengths found in the environment). 

 Remarks: No significant mortality was observed at the highest nominal concentration of 

1000 mg/kg. A 33% and 23% reduction in body weight was observed at 100 

and 500 mg/kg vs. a 14% reduction for the controls. Based on statistical 

analysis of the weight data, the no effect concentration was the nominal 250 

mg/kg dose, which was confirmed by HPLC to be 235 mg/kg. 

 Reference: Mieure, J.P., Waters, J., Holt, M. and Matthijs, E. 1990. Terrestrial safety 

assessment of LAS. Chemosphere 21:251-262. 

 Reliability: 2 Valid with restrictions 
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 (d) 

 Type : Artificial soil [X]; Filter paper [ ]; Other [ ]

 Species: Lumbricus terrestris (soil dwelling worm) 

 Endpoint: Mortality [X]; Weight [X]; Other [ ]

 Exposure period: 14 day 

 Results: LC50 >1333 mg/kg soil dw 

 NOEC = 667 mg/kg soil dw 

 Method: U.S.FDA Environmental Assessment Technical Guide No. 412, 1987. Ten 

adult earthworms (mean wt. 3.2 g/animal) were placed in each of four 

replicate one-gallon glass jars for each test concentration. Nominal test 

concentrations in the soil were 1333, 667, 333, 167, 84, and 0 mg/kg dry 

weight. Soil was comprised of 70% silica sand, 20% kaolinite clay, and 10% 

sphagnum peat. Rabbit faeces was added as food at 50 g/kg. Temperature 

was maintained at 13+

/-2oC with 24 hour continuous lighting at 700-750 lux. 

Worms were assessed for mortality, general health, body weight, and 

behavior after 7 and 14 days. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (commercial blend) with average alkyl chain length C11.6 (typical of 

LAS chain lengths found in the environment). 

 Remarks: No statistically significant mortality was observed at the highest nominal 

concentration of 1333 mg/kg. Based on weight and burrowing behavior, the 

no effect concentration was the nominal 667 mg/kg dose, which was 

confirmed by HPLC to be 613 mg/kg. It should be noted that the continuous 

lighting prevented normal feeding, which normally occurs at night on the 

surface, and thus the test conditions and results should be considered highly 

conservative. 

 Reference: Mieure, J.P., Waters, J., Holt, M., and Matthijs, E. 1990. Terrestrial safety 

assessment of LAS. Chemosphere 21:251-262. 

 Reliability: 2 Valid with restrictions 

(e) 

 Type : Artificial soil [ ]; Filter paper [ ]; Other [X] Natural soil

 Species: Folsomia fimetaria (Collembola; springtails) 

 Endpoint: Mortality [X]; Weight [X]; Other [X] molting rate, reproduction

 Exposure period: 21 days 

 Results: Results are shown in the following table. All results are in mg/kg dry weight 

of soil. 

Endpoint NOEC LOEC LC10 or 

EC10

LC50 or 

EC50

Adult survival >1000 >1000 >1000 >1000 

Juvenile survival 500 700 196 570 

Reproductive output 500 1000 147 737 

Juvenile growth <200 200 163 896 

Molting frequency <300 300 185 923 

 Method: No internationally accepted guideline was available. Adult and juvenile 

collembola were exposed to LAS mixed with 30 g of a natural, commonly 

available moist soil. Concentration levels for survival and reproduction of 

adults were control, 100, 150, 300, 500, 700 and 1000 mg/kg dry weight. 

Concentrations for survival and growth of juveniles were control, 200, 3000, 

500, 700, and 1000 mg/kg dry weight. Concentrations for molting of 

juveniles were control, 300 and 600 mg/kg dry weight. In all cases, four 

replicates per concentration were used. For measurement of molting 

frequency, juveniles were held singly on a compressed surface of soil in 

multidishes with 24 circular holes. The multidishes were assessed every 
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UNEP PUBLICATIONS 228

second day and exuviae were recorded and removed for a period of 20 days. 

Deviations from the subsequently developed ISO 11267 protocol included 

use of adults, use of 20 individuals instead of 10 per test chamber, and an 

exposure of 21 days instead of 28 days. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A350 (CAS #68411-30-3) C10-13 LAS; 50% active substance; mean 

chain length of C11.53; mean molecular weight 344 

 Remarks: The most sensitive endpoint was reproduction (EC10 = 147 mg/kg dry 

weight). Nominal concentrations are derived from tables and figures since 

values were not listed directly in the text. While there were some deviations 

from the subsequently developed ISO 11267 protocol, the procedures are 

considered reliable. 

 Reference: Holmstrup, M. and Krogh, P.H. 1996. Effects of an anionic surfactant, 

linear alkylbenzene sulfonate, on survival, reproduction and growth of the 

soil-living collembolan, Folsomia fimetaria. Environ. Toxicol. Chem. 

15:1745-1748. 

 Reliability: 2 Valid with restrictions. Well documented publication, no GLP, ECx

calculation not fully detailed.

 (f) 

 Type : Artificial soil [ ]; Filter paper [ ]; Other [X] Natural soil

 Species: Folsomia candida (Collembola; springtails) and Enchytraeus albidus

(potworm) 

 Endpoint: Mortality [X]; Weight [ ]; Other [X] reproduction

 Exposure period: 4 to 6 weeks 

 Results: The resulting EC50 values were very similar for the two species, as shown in 

the following table. All values are mg/kg dry weight. 

Species Endpoint NOEC LOEC LC10 or 

EC10

LC50 or 

EC50

Adult survival 1000 2500 750 1338 F. candida Reproduction 500 1000 480 1437 

Adult survival <750 750 511 1400 E. albidus Reproduction 750 1500 447 1143 

 The EC50 values for nitrification and CH4 production were 431 and 277 

mg/kg, respectively, for LAS. Aerobic respiration and dentrification were 

not inhibited at the test concentrations. 

 Method: LAS may enter the soil environment during sludge application. The toxic 

effects of LAS and nonylphenol (NP) to two soil invertebrates (Folsomia 

candida and Enchytraeus albidus) and five microbial processes (aerobic 

respiration, nitrification, dentrification, anaerobic CH4 production, and 

anaerobic CO2 production) were assessed in sludge-soil mixtures. 

 A coarse sandy soil collected from the upper 20 cm of an agricultural field in 

Jyndevad, Denmark was used for the laboratory experiments and 

mineralization controls. The Jyndevad soil consisted of 76.8% coarse sand, 

12.2% fine sand, 4.1% silt, 3.9% clay, 3.0% organic matter and a pH of 6.0. 

A similar soil was collected in Lundgaard for use in the microbiological tests 

was 63.1% coarse sand, 26.6% fine sand, 3.8 silt, 4.3% clay, 2.2% organic 

matter and pH of 6.1. Dewatered activated sludge collected from a WWTP 

in Lundtofte was used in all experiments. LAS was applied to the sludge in a 

demineralized water solution and allowed to sorb for 24 hours at 4oC in at N2 

atmosphere before mixing the sludge with soil. The soil insects were 

exposed to a sludge:soil ratio of 1:20 on a dry weight basis. In the 

microbiological tests, 0.5 mL aliquot solutions of LAS in methanol were 

added to 1 g of sand, the methanol allowed to evaporate, and sorbed for 24 

hours at 4oC under an N2 atmosphere to minimize biodegradation during the 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 229

sorption period. The sand was then mixed with sludge (0.3 g dry weight) and 

finally soil was mixed in with the sludge and sand. A sludge:soil ratio of 

1:100 (dry weight basis) was used to avoid depletion of oxygen. 

 Folsomia candida 

The springtail reproduction test was initiated with 10- to 12-day old juveniles 

and lasted 4 weeks. The resulting nominal LAS concentrations were 125, 

250, 500, 1000, 2500, and 4000 mg/kg sludge-soil mixture. Ten juvenile F. 

candida were added to each of the 4 replicate vials per concentration 

containing 30 g (wet weight) of the sludge-soil mixture. The numbers of 

surviving adults and offspring were counted after 4 weeks. 

 Enchytraeus albidus 

The enchytraeid worm reproduction test was initiated by introducing 10 

worms with visible clitellum to each of 4 replicate vials per concentration. 

Nominal LAS concentrations were 750, 1500, 2250, and 3000 mg/kg sludgesoil mixture (dry weight). Test duration was six weeks. After 3 weeks, the 

adult worms were removed and counted. At 6 weeks, the number of 

offspring hatched from cocoons were counted. 

 Microbiological tests 

 The toxicity of LAS to microbiological processes was evaluated using one 

aerobic system (simultaneous determination of aerobic respiration and 

nitrification) and two anaerobic systems (denitrification and 

methanogenesis). Nominal LAS concentrations were 0, 125, 250, 500, 1000, 

and 2500 mg/kg mixture (dry weight) for both the aerobic and methanogenic 

systems, and 0, 250, 500, 1500, 300, and 5000 mg/kg (dry weight) in the 

dentrifying system. 

 GLP: Yes [ ] No [ ] ? [X]

 Test Substance: The test substance for soil invertebrates consisted of an aqueous sodium salt 

solution containing 14% (w/w) of 14C-labeled C10-13 LAS (EniChem Augusta 

Industriale; purity 95%). The average alkyl chain length of C10-13 LAS was 

11.6 and the distribution was C10 14%, C11 34%, C12 32% and C13 20%. A 

pure C12 LAS, 4-(2-dodecyl)benzene sulfonate sodium salt, was used in the 

microbiological tests. 

 Remarks: Reproduction of E. albidus was the most sensitive endpoint (EC10 = 447 

mg/kg dry weight). Danish laws stipulate a maximum cut-off value of 1300 

mg/kg for LAS in sludge for agricultural use. 

 Reference: Gejlsbjerg, B., Klinge, C., Samsoe-Petersen, L., and Madsen, T. 2001. 

Toxicity of linear alkylbenzene sulfonates and nonylphenol in sludgeamended soil. Environmental Toxicology and Chemistry 20:2709-2716. 

 Reliability: 2 Valid with restrictions. Well documented publication, comparable to ISO.

4.6.2 TOXICITY TO TERRESTRIAL PLANTS 

(a) 

Species/Endpoints: See table 

Results: The following table shows the available NOEC, EC10 and EC50 values for 

twelve terrestrial plant species (in mg/kg dry weight). 

 

Species Endpoint EC10 EC50

Brassica rapa Growth 134 

Brassica rapa Growth 90 200 

Malvia pusila Growth 204 

Solanum nigrum Growth 169 
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UNEP PUBLICATIONS 230

Species Endpoint EC10 EC50

Chenopodium album Growth 164 

Amaranthus retroflexus Growth 142 

Nigella arvensis Growth 132 

Galinsoga parviflora Growth 90 

Sorghum bicolour Growth 137 

Helianthus annuus Growth 289 

Phaseolus aureus Growth 316 

Avena sativa Growth 50 300 

Sinapis alba Growth 200 300 

Test Substance: LAS (unspecified) 

Remarks: Values are extracted from a variety of original references and compiled for 

this article. NOEC values were extrapolated by applying an assessment 

factor of 10 to the EC50. This is considered an unreliable assumption as 

measured acute-to-chronic ratios for LAS in plants vary between 2 and 6. 

Reference: Jensen, J., Lokke, H., Holmstrup, M., Krogh, P.H. and Elsgaard, L. 2001. 

Effects and risk assessment of linear alkylbenzene sulfonates in agricultural 

soil. 5. Probabilistic risk assessment of linear alkylbenzene sulfonates in 

sludge-amended soils. Environmental Toxicology and Chemistry 20:1690-

1697. 

Reliability: 4 This study was given a reliability score of 4 because the original reports 

reviewed by the authors were not directly reviewed in the compilation of this 

robust summary. 

(b) 

Species: Grass, beans, radishes, potatoes 

Radiolabel: Yes 

Results: No adverse effects on plant biomass were observed at the concentrations 

tested [initial concentrations in soil = 27.2 mg/kg (grass, beans, radishes); = 

16.2 mg/kg (potatoes)] 

Temperature: Room temperature 

Method: Soil cores taken from two ecosystems were collected and placed in a climate 

controlled “plant metabolism box”. Ecosystem Section I consisted of a 

heavy, clay-like soil. Radiolabeled LAS (a defined mixture) absorbed to 

digested sludge was incorporated into the soils, after which the soils were 

planted with either grass, bush beans and radishes (Section I) or potatoes 

(Section II). The test systems were maintained under a defined standard 

climate (i.e., an average day in June in Northern Germany) for the vegetative 

period (76 and 106 days, respectively for Sections I and II). At the end of 

the growing season samples were collected from plants and soil and 

subjected to radioanalysis. 

GLP: Yes [ ] No [ ] ? [X]

Test Substance: LAS. The authors state that they tested a defined mixture of LAS, but do not 

report the composition in this paper. 

Reference: Figge, K. and Schoberl, P. 1989. LAS and the application of sewage sludge 

in agriculture. Tenside Surf. Det. 26:122-128. 

Reliability: 2 Valid with restrictions 

(c) 

 Species: radish, tomato, oats 

 Endpoint: Emergence [ ]; Growth [X]; Other [ ]

 Exposure period: 14 day 

 Results: EC50 >77.1 mg/kg soil dw 

 NOEC = 25.7 mg/kg soil dw 

 Method: OECD Guide-line 208 “Terrestrial Plants, Growth Test”. 
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 GLP: Yes [ ] No [ ] ? [X]

 Test substance: Commercial LAS with an average carbon chain length of C11.8. 

 Remarks: Information as cited in IUCLID Data Sheet for CAS #68411-30-3. The 

substance was tested in the range of 2.57 to 257 mg MBAS/kg 

 Nominal concentrations, synthetic soil, static, pH 5.0-7.5, temperature 20-25 

oC. Results are expressed as mg MBAS per kg soil. First Observed Effect 

Concentration (FOEC) is 77.1 mg MBAS/kg, EC50 is about 77.1 but below 

257 mg MBAS/kg. 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished data (Registry No. 5929). 

 Reliability: 4 Not assignable 

 

(d) 

 Species: Brassica rapa (Dicotyledon) 

 Endpoint: Emergence [ ]; Growth [ ]; Other [X] emergence of seedlings 

 Exposure period: 21 day 

 Results: NOEC = 50 mg/kg soil dw 

 FOEC = 150 mg/kg soil dw 

 Method: EEC Directive 79/831, Annex V; EEC Ring Test C (L1) 3: Higher Plant, 

1986. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Data refer to 100% active ingredient 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 

 (e) 

 Species: Lycopersicum esculentum (tomato) 

 Endpoint: Emergence [ ]; Growth [ ]; Other [X] emergence of seedlings 

 Exposure period: 21 day 

 Results: NOEC = 50 mg/kg soil dw 

 FOEC = 150 mg/kg soil dw 

 Method: EEC Directive 79/831, Annex V; EEC Ring Test C (L1) 3: Higher Plant, 

1986. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Data refer to 100% active ingredient 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 (f) 

 Species: Avena sativa (Monocotyledon) 

 Endpoint: Emergence [ ]; Growth [ ]; Other [X] emergence of seedlings 

 Exposure period: 21 day 

 Results: NOEC = 50 mg/kg soil dw 

 FOEC = 150 mg/kg soil dw 

 Method: EEC Directive 79/831, Annex V; EEC Ring Test C (L1) 3: Higher Plant, 

1986. 

 GLP: Yes [ ] No [X] ? [ ]
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 232

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

11.6 

 Remarks: Data refer to 100% active ingredient 

 Reference: European Commission. 2000b. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing Henkel KGaA, 

unpublished results (Registry No. 5929). 

 Reliability: 4 Not assignable 

 (g) 

 Species: Sorghum bicolour (crop sorghum), Helianthus annuus (sunflower), 

Phaseolus aureus (mung bean) 

 Endpoint: Emergence [ ]; Growth [X]; Other [ ] 

 Exposure period: Emergence: 7 days; Growth: 21 days 

 Results: NOEC = 100 mg/kg soil dw (all three species) 

EC50 = 167, 289, and 316 mg/kg dw (for listed above listed species, 

respectively) 

 Method: A laboratory standard operating procedure based on OECD Guideline 208 

(OECD 1984) was used. The test was conducted in an artificial soil 

consisting of commercially available potting compost (WC-B) and washed, 

sieved (1 mm mesh), dried (temperature and time not reported) silver sand 

(1:9 potting soil:washed sand). Concentrations tested were control, 1, 10, 100 

and 1000 mg/kg dw. Deviations from the guideline included: % particles less 

than 20 μg not given; 4.1% instead of maximum 3% organic carbon in the 

test soil; sand was sieved with 1 mm mesh instead of 0.5 mm mesh; weight 

and variability of seeds not reported. The EC50 values were calculated with 

probit analysis according to Finney (1971). 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: C11 LAS (57.3% activity; average MW = 343) 

 Remarks: The NOEC is for the most sensitive endpoint, which was growth (shoot fresh 

weight). Nominal concentrations not measured. 

 Reference: Windeat, A.J. 1987. Effects on the growth of Sorghum bicolour, Helianthus 

annuus, Phaseolus aureus. Unilever study report BL/B/3078 (R118). 

Unilever Research Port Sunlight Laboratory, Sunlight, UK. 

 Reliability: 2 Valid with restrictions. 

 (h) 

 Species: Araucaria heterophylla 

 Endpoint: Foliar penetration of NaCl 

 Exposure period: 4 weeks 

 Methods: The influence of surfactants on foliar NaCl uptake was examined in Norfolk 

Island Pines (Araucaria heterophylla). Plants were exposed to seawater with 

different concentrations of LAS by spraying with a handheld sprayer three 

times a week for four weeks. Plants were sprayed until the foliage was 

wetted sufficiently for the spray to run off. 

 Results: At 10 mg/L of LAS, which corresponds with a reduced surface tension of 32 

mN/m, the Na+

 content in the foliage increased almost tenfold to a level of 

approximately 500 μmol/g dw and damage symptoms were recorded. 

 Remarks: The potential for LAS and other surfactants to influence defoliation in coastal 

trees was reviewed in a literature review sponsored by ERASM in 2002. In 

laboratory studies in which young trees are exposed to artificial sea spray, it 

has been demonstrated that the presence of surfactants at a concentration that 

causes a dynamic surface tension < 30 mN/m lead to an increased foliar 

penetration of NaCl via the stomata. It was found that a low surface tension 

increases the contact angle with the leave and makes it possible for an 

aqueous solution to enter the stomata. This is a hypothesized mechanism of 

defoliation. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 233

 Reference: 1) Grieve, A.M. and Pitman, M.G. 1978. Salinity damage to Norfolk Island 

pines caused by surfactants. III. Evidence for stomatal penetration as the 

pathway of salt entry to leaves. Aust. J. Plant. Physiol. 5:397-413. 

 2) Hamwijk, C. 2002. Literature study: Exposure and possible indirect 

effects of aerosol borne surfactants on coastal vegetation. TNO Chemistry 

report, Study number 02-4077/01. Prepared for CEFIC ERASM. 

 Reliability: 4 Not assignable. Original studies were not directly reviewed. 

(i) 

 Species: Pinus halepensis (pine tree) 

 Endpoint: Accumulation of LAS in plant tissues 

 Exposure period: 2 minutes 

 Method: The concentration of LAS tested was 1.7 x 10-4 mol/kg, which is equivalent 

to 58 mg/L based on a C11.6 LAS with a molecular weight of 342. Three 

batches of ten 2-year old pine trees were immersed for 2 minutes in distilled 

water alone (batch 1), in LAS-distilled water (batch 2), or LAS-synthetic sea 

water (batch 3). The objective was to simulate the exposure to severe storms 

on the seashore. Only the aerial parts of the plants were immersed in a large 

volume container (50 x 50 x 8 cm) containing 1 L of the respective solutions. 

The root system was isolated with a plastic bag enclosure and not exposed 

directly to the solutions. Controls were run on ten plants. Trees were 

removed from the solutions and gently shaken to eliminate liquid droplets. 

Radiolabeled and control trees were kept in a greenhouse for 48 hours under 

a 16:8 day:night photoperiod, temperatures of 22° C (day):16° C (night), and 

a constant relative humidity. Before analysis, the trees were washed twice in 

distilled water for 1 minute while shaking to simulate rainfall. Trees were cut 

back at the soil surface and the aerial part divided into several parts for 

analysis (epicuticular wax from needles, dewaxed needles, and remaining 

plant material consisting of branches without needles and tree stem). 

Respective samples were extracted, prepared, and the radioactivity measured 

in each fraction using a liquid scintillation cocktail and spectrometer. For 

scanning electron microscopy, 48 hours after the exposure period ten needles 

from each of the five replicates of treated and control plants were cut into 

small segments and air dried, fixed on aluminium stubs with conductive glue 

and carbon coated. Axial surfaces were examined with a Stereoscan 90B 

electron microscope with 15 kV acceleration voltage. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Stated by authors as LAS with an alkyl chain length of 12 carbons, with no 

further information. For our review, we have assumed this to be the typical 

European C11.6 LAS (average MW = 342). LAS was radiolabeled with 35S in 

the sulphonate group attached to the phenyl ring and had a specific 

radioactivity of 8712 μCi/mol. 

 Results: The amount of LAS (as a percent of total in solution; mean ± SD) found in 

each analyzed fraction of the trees and the wash water is shown below: 

Fraction Distilled water only 

(Batch 1 ) 

LAS-distilled water 

(Batch 2 ) 

LAS-seawater 

(Batch 3 ) 

Epicuticular waxes ~ 0 0.18 ± 10 1.48 ± 1.03 

Dewaxed needles ~ 0 ~ 0 0.09 ± 0.16 

Remaining plant 

material ~ 0 ~ 0 ~ 0 

Distilled water wash ~ 0 0.17 ± 0.06 1.41 ± 0.57 

 The amount of uptake and percent of the total radioactivity incorporated in 

each fraction for the LAS-seawater and LAS-distilled water treatments are 

shown below: 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 234

 LAS-seawater treatment LAS-distilled water treatment 

35S LAS uptake μg/mg dw 

 Epicuticular waxes 9.96 ± 3.10 4.90 ± 1.10 

 Dewaxed needles 0.007 ± 0.001 ~ 0 

 Remaining plant material 0.006 ± 0.001 ~ 0 

% of total radioactivity 

 Epicuticular waxes 89.70 ± 6.02 96.90 ± 2.34 

 Dewaxed needles 9.90 ± 5.95 ~ 0 

 Remaining plant material 0.37 ± 0.23 3.10 ± 0.02 

 After LAS exposure in seawater or distilled water, alterations of the 

epicuticular wax fine structure were observed by SEM. 

 Remarks: Forty-eight hours after exposure, half of the radioactivity detected was in the 

epicuticular waxes, with nearly all the rest in the washing solution. LAS was 

absorbed to a much greater extent in the seawater treatment (surface tension 

= 29 mN/m) than in the distilled water treatment (surface tension = 45 

mN/m). LAS accumulated mainly in the epicuticular wax of the needles. 

Very little accumulated in the dewaxed needles or remaining plant material. 

More dramatic changes in epicuticular wax fine structure were observed 

following LAS treatment in seawater than in distilled water. These 

observations are in agreement with the studies reported by Hamwijk (2002) 

and Grieve and Pitman (1978), who demonstrated that low surface tension 

(<30 mN/m) could increase foliar penetration of salts from sea spray (dossier 

section 4.6.2h). 

 Reference: Richard, B., Grieu, P., Badot, P.M., and Garrec, J.P. 1996. Influence of 

marine salts on the localization and accumulation of surfactant in the needles 

of Pinus halepensis Mill. Ann. Sci. For. 53:921-930. 

 Reliability: 2 Valid with restrictions 

 

4.6.3 TOXICITY TO OTHER NON MAMMALIAN TERRESTRIAL SPECIES (INCLUDING 

AVIAN)

 Species: Chicken (Leghorn hens) 

 Endpoint: Mortality [X]; Reproduction rate [ ]; Weight [ ]; Other [X] egg quality 

 Exposure period: 45 day 

 Results: NOEC = 200 mg/kg diet 

 Method: Ten month old Leghorn chicken hens were given a dosage of 200 mg/kg in 

drinking water for 45 days. Four groups of six hens were used in the 

treatment group, with an additional six hens used as a control group. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Commercial LAS 

 Remarks: No mortality or adverse effects on egg quality occurred at 200 mg/kg. While 

this is a non-standard study, it does indicate that up to 200 mg/kg in the 

drinking water does not adversely affect hens or egg laying. 

 Reference: Lopez-Zavalla, A., de Aluja, A.S., Elias, B.L., Manjarrez, L., Buchmann, A., 

Mercado, L., and Caltenco, S. 1975. The effects of ABS, LAS and AOS 

detergents on fish, domestic animals and plants. Prog. Water Technol. 7:73-

82. 

 Reliability: 2 Valid with restrictions

4.7 BIOLOGICAL EFFECTS MONITORING (INCLUDING BIOMAGNIFICATION)

 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 235

 (a) 

 Type of test: static [ ]; semi-static [ ]; flow-through [ ]; other [X] outdoor experimental 

streams 

 open-system [X]; closed-system [ ] 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method and Results: An integrated model stream ecosystem fate and effects study of a C12LAS 

homologue, with a high content (35.7%) of its most hydrophobic and toxic 

2-phenyl isomer, was performed in the summer and fall of 1996 in Procter 

and Gamble’s Experimental Stream facility. The study addressed responses 

of periphytic microbes, immature benthic fauna including abundance and 

drift, and emergence of adult insects in a 56-day exposure. Exposures 

ranged from 126 to 2978 μg/L and were continuously presented in a singlepass, flow through test system. Microbial heterotrophs acclimated to 

C12LAS exposure quickly (14 days) and biodegraded C12LAS at all 

concentrations. Blue-green algae responded by increasing in abundance 

with increasing C12LAS concentration. Invertebrates responded by 

increased drift and reduced benthic abundances at concentrations exceeding 

293 μg/L. Emergence at 927 μg/L also declined relative to the control. 

Adverse responses for mayflies and chironomids were indicated using 

univariant statistical techniques. Multivariant techniques indicated these 

taxa plus molluscs, aquatic worms, caddisflies, and stoneflies were 

impaired at some concentrations. Bioavailability of C12LAS was 

investigated in streams as a function of the total suspended solids load in 

the water column driven by local weather and watershed patterns. A 

continuous bioavailability model indicated exposure was reduced by an 

average of 8.5 ± 8.9%. A model ecosystem NOEC (no-observed-effectconcentration) was concluded to be 293 μg/L based on measured water 

column exposure and adjusted to 268 μg/L by the bioavailability model. A 

summary of selected population and community responses at 8 weeks from 

the current study is shown in the following table: 

Community/Measure Dose 

Response Temporal NOEC (μg/L) 

Heterotrophic microbial 

Biomass (total lipid phosphate/mm2

) 

Amino acid uptake (3

H dpm/mm2/min) 

Phospholipid fatty acid (PLFA) distr. 

Surfactant mineralization (% CO2) 

NS 

NS 

Shift at >293 μg/L 

Acclimation at all conc. 

Autotrophic microbial 

Bicarbonate uptake (14C dpm/mm2

/min) 

Algal density (cells/mm2

) 

Algal biovolume (μm3

/mm2) 

Blue-green algal density (cells/mm2

) 

Green algal density (cells/mm2

) 

Diatom algal density (cells/mm2

) 

Algal richness 

Dominant taxa (cells/mm2

) 

 Cocconeis placentula 

 Melosira varians 

 Chrococcus sp.

 Nitzschia dissipata 

 Navicula salinarum v. intermedia 

 Pleurosira (= Biddulphia) laevis 

 Nitzschia inconspicua 

 Nitzschia palea 

 Diatoma vulgare 

+ 

NS 

NS 

++ 

NS 

NS 

- 

- 

NS 

+ 

NS 

NS 

NS 

++ 

+ 

-- 

+ 

++ 

- 

- 

+ 

++ 

+ 

-- 

927 

927 

927 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 236

 Gyrosigma acuminatum - - 927 

Invertebrates 

Richness 

Diversity (Shannon-Weaver) 

Total abundance (No./m2

) 

Insect abundance (No./m2

) 

EPT abundance (No./m2

) 

Mayfly abundance (No./m2

) 

Caddisfly abundance (No./m2

) 

True fly abundance (No./m2

) 

Chironomid abundance (No./m2

) 

Mollusk abundance (No./m2

) 

Oligochaete abundance (No./m2

) 

Dominant populations (No./m2

) 

 Baetis sp. (mayfly) 

 Isonychia sp. (mayfly) 

 Stenonema sp. (mayfly) 

 Thienemannimyla sp. (chironomid) 

 Tanytarsus sp. (chironomid) 

 Cricotopus sp. (chironomid) 

 Polypedilum sp. (chironomid) 

 Reotanytarsus sp. (chironomid) 

 Naididae (aquatic worm) 

NS 

NS 

-- 

NS 

- 

NS 

NS 

NS 

NS 

NS 

-- 

b 

--- 

NS 

--- 

++ 

+ 

+ 

NS 

NS 

-- 

- 

-- 

--- 

--- 

++ 

+ 

+ 

293 

927 

293 

927 

293 

a Plus (+) and minus (-) signs indicate whether the response significantly increased or decreased from the control condition 

(α = 0.05). The strength to the response was graded as slight (+/-), moderate (++/--), or great (+++/---) based on statistical 

analyses. NS indicates not significant. b

 Taxon too low in abundance, emerged.

 A literature review of 13 available model ecosystem studies was conducted 

and NOEC conclusions were adjusted by a structure-activity-relationship to 

dodecyl chain length (sulfophenyl position and distribution being ignored 

due to lack of information in the reviewed studies). Lentic studies (n = 7) 

were found to have higher NOECs than lotic studies (n = 6) and were more 

variable. Mean NOEC ± standard deviations for all studies, lentic studies 

only, and lotic studies only were 3320 ± 6040, 5720 ± 7640, and 530 ± 430 

μg/L, respectively. Interpretation of results for anomalies from specific 

studies suggest the importance of experimental design, use of laboratory 

versus natural surface water, biological complexity of the test system, and 

physical test system design as relevant factors for consideration. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Dodecyl linear alkylbenzene sulfonate (C12LAS) (CAS# 25155-30-0) 

 Remarks: The mesocosm studies indicate that the lower limits of field studies can be 

considered between 0.12 to 0.5 mg/L. It should be noted that the lowest 

NOEC value (0.12 mg/L) was observed in an artificial stream study 

(Tattersfield et al. 1995, 1996) in which river water was seeded from field 

collections and a hydrocyclone used to prevent colonization of biota 

throughout the study. Drift therefore comprised only emigration and not 

immigration. Thus, the Tattersfield et al. study is an ecologically restrictive 

study design that ignores the importance of recovery vectors present in 

natural systems. The current study (Belanger et al. 2002) did not have 

these design limitations. The current critical review of all field studies, 

including the Tattersfield et al. study, concluded that a NOEC = 0.27 mg/L 

for a C12LAS homologue (0.37 mg/L if normalised to C11.6 LAS) is the 

most reliable, robust and defendable value for the aquatic freshwater 

ecosystem. This is a key study for aquatic toxicity in model ecosystems (see 

SIAR Table 15). 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 237

 Reference: Belanger, S.E., Bowling, J.W., Lee, D.M., LeBlanc, E.M., Kerr, K.M., 

McAvoy, D.C., Christman, S.C., and Davidson, D.H. 2002. Integration of 

aquatic fate and ecological responses to linear alkyl benzene sulfonate (LAS) 

in model stream ecosystems. Ecotoxicology and Environmental Safety. 

52:150-171. 

 Reliability: 1 Valid without restriction 

 (b) 

 Results: Time averaged mean measured concentrations over the 28 day exposure 

period were 0.03, 0.06, 0.12, 0.32, 0.52, 1.0 and 3.0 mg/L in the artificial 

streams and 0.24, 0.81, and 2.0 mg/L in the downstream pools. 

 Problems were experienced with dosing LAS into the streams after day 45 

due to extreme weather conditions causing freezing of stock solutions of LAS 

in the delivery tubes. Results should therefore be treated with caution as 

exposure data is extrapolated from 45 to 56 days. Time averaged mean 

measured concentrations over the first 45 days of the 56 day study period 

were 0.03, 0.06, 0.12, 0.32, 0.52, 1.0 and 3.0 mg/L in the artificial streams 

and 0.22, 0.69, and 1.6 mg/L in the downstream pools. 

 A total of 65 taxa were identified in the artificial streams and downstream 

pools. Effects data were generated for 24 endpoints, which included ten 

invertebrate taxa, two fish species and algae. The inclusion of downstream 

pool sections increased the range of taxa investigated. The downstream pool 

community appeared generally less sensitive to the LAS than the stream 

channel community. Individual taxa were found to differ in susceptibility to 

LAS depending on their location in the stream channels. The same taxa were 

generally more susceptible when in the riffle section than in the pool sections. 

This may have been the result of differences in exposure or physiological 

state of the organism. 

 Results from the first 28 days of the study concluded that there were no 

NOECs below 0.12 mg/L. Extending the study to 56 days resulted in no 

change in NOECs for the majority of endpoints. NOECs determined in the 

artificial streams were in the range of 0.03 to >3.0 mg/L although the most 

reliable NOECs were in the range 0.12 to 3.0 mg/L. In the downstream pools 

the NOECs ranged from 0.69 to >1.6 mg/L. Only two NOECs were below 

0.12 mg/L; the population density of Gammarus pulex in the riffle and 

population density of Baetis sp. Some uncertainty is associated with the 

extended 56 day study due to three main factors. First, lack of exposure data 

between days 45 and 56. Further uncertainty is associated with the low 

NOECs for some end points, particularly for G. pulex in the riffle section of 

the artificial streams. Second, the uncertainty in the lower NOEC is due to 

the times dependent effects (increased susceptibility at 56 compared to 28 

days) only being observed for individuals of G. pulex in the riffle but not the 

pool section of the artificial streams. Reduction in NOEC from 28 to 56 days 

for G. pulex in the riffle was not evident in the pool section of the artificial 

streams where the 28 and 56 day NOEC was 0.52 mg/L. The exact cause of 

the difference between riffle and pool is unknown. Third, uncertainty was 

due to variability of the G. pulex data and sensitivity to statistical 

transformation. 

 Conclusion: The lowest NOEC value observed in this artificial stream study was 0.12 

mg/L. However, the river water was seeded from field collections and a 

hydrocyclone used to prevent colonization of biota throughout the study. 

Drift therefore comprised only emigration and not immigration. This is an 

ecologically restrictive study design that ignores the importance of recovery 

vectors present in natural systems. 
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 Method: Communities of freshwater organisms were established in eight artificial 

streams and four downstream pools over a 10 day period, five weeks prior to 

the onset of dosing. Seven nominal LAS exposure concentrations (0.02, 

0.05, 0.1, 0.3, 0.5, 1.0 and 3.0 mg/L) and an untreated control were randomly 

allocated to the eight artificial streams to yield a regression model experiment 

design. Four of the streams (Control, 0.3, 1.0 and 3.0 mg/L) were connected 

to downstream pools. Effects measurements were taken after 28 and 56 days. 

 The streams were operated as once-through systems with a residence time of 

three minutes. Each individual stream was divided approximately equally 

into a slow flowing pool section (0.20 m water depth, ~3 cm/s flow velocity) 

and a faster flowing riffle section (0-0.02 m water depth, ~30 cm/s flow 

velocity). The total volume of water in each stream system was 240 litres. 

The downstream pools consisted of plastic cylindrical tanks (1.04 m diameter 

and 510L capacity) with a residence time of approximately 2 days. 

 The water used in the study was from a local chalk stream with a hardness of 

194 to 392 and 280 to 378 mg/L CaCO3 in the streams and downstream 

pools, respectively. The water temperature was relatively low ranging from 

3.0 to 13.2oC and 3.2 to 13.1oC in the streams and downstream pools, 

respectively. Concentrations of suspended solids and total organic carbon 

(TOC) in the artificial streams were low (suspended solids 1.8 to 3.0 and 0.4 

to 6.6 mg/L and TOC 1.5 to 5.2 and 1.9 to 7.9 mg/L in the steams and 

downstream pools, respectively). The low concentrations of suspended 

solids and TOC would have tended to maximise the availability of LAS in 

the system. Also Goyer et al. showed that toxicity of surfactants to daphnia 

correlated with water hardness. Given the above conditions, effects data 

generated in this system should be judged to be at the most sensitive end of 

the distribution. 

 Remarks: Effects measurements were taken after 28 and 56 days. The streams were 

operated as once-through systems with a residence time of three minutes. 

Each individual stream was divided approximately equally into a slow 

flowing pool section and a fast flowing riffle section.

 There is uncertainty connected to the extended 56 day study having to do 

with the lack of exposure data between days 45 and 56. Uncertainty is also 

linked with the low NOEC values for some of the end points. This is 

related to time dependant effects (increased susceptibility at 56 compared to 

28 days) being observed only for individuals of G. pulex in the riffle but not 

the pool section of the artificial streams and variability of the G. pulex data 

and sensitivity to statistical transformation. The NOEC values of ≥0.12 

mg/L determined after 28 days of exposure are considered estimates of no 

effect for LAS. For the previously mentioned reasons, the indications of 

NOECs below 0.12 mg/L from the extended 56 day study appear to be 

outliers and are not considered reliable for assessment purposes (i.e., would 

be Klimish 3). 

 Also, it should be noted that a hydrocyclone was used to prevent 

colonization of biota throughout the study. Thus, drift comprised only 

emigration and not immigration. Therefore, the study design is 

ecologically restrictive in that it ignores the importance of recovery vectors 

present in natural systems. In a review of 13 model ecosystem studies, 

including this one, Belanger et al. (2002) concluded that a NOEC of 0.27 

mg/L for a C12LAS homologue is the most reliable, robust and defendable 

vaule for aquatic freshwater ecosystems. 

 Test Substance: C10-13 LAS, 38.3% active matter, average carbon chain length = 11.52 

 Reference: 1) Tattersfield, L.J., Holt, M., Girling, A.G., Mitchell, G.C., Pearson, N., and 

Ham, L. 1995. The fate and effects of linear alkylbenzene sulfonate (LAS) 

in outdoor artificial streams and pools. External report. Shell Research 

Limited, Sittingbourne Research Centre. Document No. SBER.95.009. 
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 2) Tattersfield, L.J, Mitchell, C.G., Holt, M., Girling, A.G., Pearson, N., and 

Ham, L. 1996. Linear alkylbenzene (LAS): Fate and effects in outdoor 

artificial streams and pools – An extended study. Internal report. Shell 

Research and Technology Centre, Thornton. Document No. TNER.96.005. 

 Reliability: 4 Not assignable due to restrictive test design and inconsistencies in the data 

 (c) 

 Type: Aquatic [ ]; Field [ ]; Soil [X]; Other [ ] 

 Results: LAS had no effect on heterotrophic respiration in the sludge compartment but 

stimulated activity and metabolic quotient (microbial activity per unit of 

biomass) in the surrounding soil. Basil respiration (BR) was significantly 

stimulated up to 60 days in the 0-10 mm compartment, but only after 60 and 

82 days in the 10-30 mm compartment. No significant stimulation in BR was 

observed at 30-60 mm. Substrate-induced respiration stimulation was 

variable and restricted only to soil in the 0-10 mm compartment. Autotrophic 

ammonia oxidation was initially inhibited in the LAS-spiked sludge, which 

led to dramatic but transient increases of NH4

+

 availability in the sludge and 

surrounding soil, subsequently stimulating soil ammonia oxidizers. As 

judged from a bioluminescence toxicity assay, however, LAS or other sludge 

components never accumulated to toxic levels in the soil and the LAS 

tolerance of the indigenous microbes further remained unchanged following 

LAS exposure. Bioluminescence was slightly, but not significantly, reduced 

in the 0-10 mm compartment at the first sampling, but not thereafter and not 

in the 10-30 or 30-60 mm compartments. LAS effects on the microbial 

populations largely occurred during the first two months and were confined 

to soil closer than 30 mm from LAS-spiked sludge. 

 Test Substance: C10-13 LAS, sodium salt; average alkyl chain length C11.6

 Method: Well-defined bands of sewage sludge spiked with 0 (control), 7.1, or 31.3 g 

LAS/kg dry weight were applied to loamy sand soil in an agricultural field in 

Lundgaard, Denmark using a random block design. To each block, three 

sludge bands (one per LAS treatment) were carefully applied such that the 

bands were eventually applied at a specific soil depth of approximately 6 to 

10 cm and covered by soil. All treatments were replicated five times. A few 

days after sludge application, the entire experimental site was sown with oats 

in order to make experimental conditions as realistic as possible. Sampling 

for microbial parameters was done on a weekly to monthly basis for the first 

100 days, with the last samples being taken approximately one year after the 

start of the experiment. A rectangular corer providing a 40 mm wide cross 

section of the sludge bands and the surrounding soil was sectioned into four 

compartments representing various distances (0-10, 10-30, 30-60 mm) from 

the sludge. At each sampling date, two replicate cores from each sludge band 

were sampled and the corresponding samples from the two cores were 

pooled. Microbial parameters measured included basal respiration (BR), 

substrate-induced respiration (SIR), potential ammonia oxidation (PAO), and 

pollution-induced community tolerance. Bioluminescence toxicity tests were 

also conducted and correlated with ammonia oxidation activity as a measure 

of the physiological state of the cells. Two-way analysis of variance statistics 

were used for each sampling date, followed by Dunnett’s test. Data were 

transformed if necessary. 

 Remarks: Measured LAS concentrations were 0.069 (control), 7.1 and 31.3 g/kg dw 

sludge. Results strongly suggest that disposed of LAS-contaminated sludge 

will not produce a significant adverse effect on the function of the soil 

microbial community under field conditions. Measured effects generally 

lasted two months or less and were confined to soil closer than 30 mm from 

the LAS-spiked sludge. No signs of long-term selection due to toxicity were 

noted. According to the authors, the study should be considered a worst-case 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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due to the application of high LAS concentrations only occasionally 

encountered in sewage sludge, the use of LAS-spiked sludge possible 

overestimating the actual bioavailability relative to aged surfactants in natural 

sludge, the application of relatively large (4 x 4 cm) two dimensional sludge 

bands possible retarding oxygen intrusion and consequently LAS degradation 

in the sludge relative to smaller spherical sludge clumps present under more 

realistic field conditions, and the use of a coarse, sandy soil with relatively 

low organic matter content. While NOEC, LOEC, EC50, etc. were not 

calculated, significant differences from the control sludge were detected in 

the high (31.3. g/kg dw sludge) and in the low (7.1 g/kg dw sludge) 

treatments. Therefore, the NOEC should be <7.1 g/kg dw sludge. 

 Reference: Brandt, K.K., Krogh, P.H., and Sorensen, J. 2003. Activity and population 

dynamics of heterotrophic and ammonia-oxidizing microorganisms in soil 

surrounding sludge bands spiked with linear alkylbenzene sulfonate: a field 

study. Environ. Toxicol. Chem. 22:821-829. 

 Reliability: 2 Valid with restriction. Well documented publication, no GLP, 

concentrations only measured at start of experiment 

 (d) 

 Type: Aquatic [ ]; Field [ ]; Soil [X]; Other [ ] 

 Results: No short-term or long-term (4 years) adverse effects on 9 different microbial 

functions/processes or the abundance or diversity of microarthropods and 

earthworms were observed after sludge application of up to 21 t dw/ha dry 

weight, corresponding to a LAS dose of approximately 35 kg/ha, or 

approximately 15 mg/kg dry weight. 

 Method: This study was conducted by the Danish EPA to assess the effects of using 

sewage sludge applications on soil fauna and microbial processes in winterwheat and barley undersown with clover grass. Three levels of sludge and 

cow dung (3.5, 7, and 21 t dw/ha) were tested along with control fields. 

Concentrations of LAS in sludges from the two waste water treatment plants 

were 1,100 and 1,700 mg/kg. 

 Test Substance: LAS (unspecified) 

 Reference: 1) Jensen, J., Lokke, H., Holmstrup, M., Krogh, P.H. and Elsgaard, L. 2001. 

Effects and risk assessment of linear alkylbenzene sulfonates in agriculture 

soil. 5. Probabilistic risk assessment of linear alkylbenzene sulfonates in 

sludge-amended soils. Environ. Toxicol. Chem. 20:1690-1697. 

 2) Jensen, J. and Krogh, P.H. 1999. Ecological assessment of sewage 

sludge application. Proceedings, Nordiska Jordbruks forskares Forening, 

Seminar 292. Jokionen, Finland, November 23-25, 1998, pp. 98-100. 

3) Krogh, P.H., Holmstrup, M., Jensen, J., and Peterssen, S.O. 1997. 

Ecotoxicological assessment of sewage sludge in agricultural soil. Working 

Report No. 69. Ministry of Environment and Energy, Danish Environmental 

Protection Agency. 

Reliability: 2 Valid with restrictions 

 (e) 

 Type: Aquatic [ ]; Field [ ]; Soil [X]; Other [ ]

 Species: cellulolytic bacteria, fungi and actinomycetes and microbial parameters 

 Exposure Period: up to 8 weeks 

 Results: EC50 = 17 to 128 mg/kg dry weight for all parameters other than as indicated. 

EC10 = < 8 to 22 mg/kg dry weight for all parameters other than as indicated. 

Except for β-glucosidase activity, basal respiration, and total PLFA content, 

all soil parameters were sensitive to LAS, with EC10 values in the range of 

less than 8 to 22 mg/kg dry weight. The authors indicate that this probably 

reflected a similar mode of LAS toxicity, ascribed to cell membrane 

interactions, and showed than sensitivity to LAS was common for various 
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UNEP PUBLICATIONS 241

soil microorganisms. The extracellular β-glucosidase activity was rather 

insensitive to LAS (EC10, 47 mg/kg dry weight), whereas the basal soil 

respiration was not inhibited even at 793 mg/kg dry weight. This was 

interpreted as a combined response of inhibited and stimulated compartments 

of the microbial community. The PLFA content showed no decrease even at 

488 mg/kg. 

 Analytical monitoring: Yes [X] No [ ] ? [ ] 

 Method: The short-term effects of aqueous LAS on microbial parameters was tested in 

a sandy agricultural soil that was incubated for up to 11 days. The assays 

included 10 microbial soil parameters: ethylene degradation; potential 

ammonium degradation; potential dehydrogenase activity; β-glucosidase 

activity; iron reduction; populations of cellulolytic bacteria, fungi and 

actinomycetes; the basal soil respiration; and the phospholipid fatty acid 

(PLFA) content. Soil from the plough layer was sampled at an agricultural 

field at Lundgaard, Denmark. The soil consisted of coarse sand (67%), fine 

sand (16%), silt (8.6%), clay (6.2%), humus (2.7%) and had a total carbon 

content of 1.5%. The soil had not been treated with sewage sludge and had 

not been sprayed with pesticides in the last two years. For the experiments 

with aqueous LAS, triplicate soil incubations were amended with the 

appropriate LAS solutions to produce the LAS contents. The soils were 

carefully mixed and incubated in the dark and duplicate soil samples for LAS 

analyses were frozen at the beginning of the incubation period. EC10 and 

EC50 values were calculated by a linear-interpolation analysis (ICp), which 

was based on bootstrapping. The NOECs and LOECs were determined by 

Dunnett’s test using a SAS analysis-of-variance procedure. Nominal 

concentrations were control, 8, 22, 62, 174 and 488 mg/kg dw soil, except for 

BR (control, 0.8, 8, 79 and 793 mg/kg dw soil). On average, 84 to 95% of 

the nominal concentrations were initially recovered by the chemical analysis. 

Nominal levels were used for the calculation of effect concentrations. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: C10-13 LAS obtained as an aqueous sodium salt solution with a LAS content 

of 16.1% (w/w), Na-LAS average molecular weight = 342 g/mol, 

distribution: C10 14%, C11 34%, C12 31%, and C13 21% 

 Remarks: The study demonstrated that LAS inhibited specific compartments of the soil 

microbial community. The lowest EC10 values for microbial soil parameters 

were slightly higher than the predicted no-effect concentrations recently 

derived for plants and soil fauna (~5 mg/kg dry weight). A subsequent study 

(Elsgaard et al. 2001, Part 2) further indicated that the short-term effects 

observed for aqueous LAS on soil microbiology were modified by the dosage 

of LAS with sewage sludge and by a prolonged incubation time. The data 

suggest that a terrestrial risk assessment based on short-term affects of 

aqueous LAS fully encompasses the risk that may occur when LAS is applied 

to agricultural soil by means of sewage sludge. 

 Reference: 1) Elsgaard, L., Petersen, S.O., and Debosz, K. 2001a. Effects and risk 

assessment of linear alkylbenzene sulfonates in agricultural soil. 1. Shortterm effects on soil microbiology. Environmental Toxicology and Chemistry 

20:1656-1663. 

 2) Elsgaard, L., Petersen, S.O., and Debosz, K. 2001b. Effects and risk 

assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects 

on soil microbiology as influenced by sewage sludge and incubation time. 

Environmental Toxicology and Chemistry 20:1664-1672. 

 Reliability: 2 Valid with restrictions. Well documented publication, no GLP, ECx

calculation not fully detailed. 

(f) 

 Type: Outdoor experimental stream 
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UNEP PUBLICATIONS 242

 Methods: Species or ecosystem studied. Taxonomic groups tested were periphyton, 

detritus, invertebrates, snails, amphipods, and fish. One concentration was 

tested in triplicate. The substance was dosed eight times at seven day 

intervals. Test duration 45 days. 

 Effects monitored: Population and community effects. 

 Results: The best estimated NOEC is >0.36 mg/L. 

 For fish (caged larval fathead minnows) no effects on mortality occurred at 

the only concentration tested. However growth was significantly decreased 

in the dosed systems. The authors state that this is caused by the better food 

and light conditions in the controls. 

 Growth of periphyton, the degradation rate of detritus, population and 

community growth of invertebrates and the population density of snails were 

not inhibited at the only concentration tested. 

 For Amphipods no NOEC could be determined. Mortality was highest 

(45%) at a control location. 

 Chemical analysis: Concentrations were measured. 

 Test Substance: LAS; average chain length C11.9 (representative of homologues found in 

typical sewage effluents in the U.S.). 

 Reference: Fairchild, J.F., Dwyer, F.J., La Point, T.W., Burch, S.A., and Ingersoll, C.G. 

1993. Evaluation of a laboratory-generated NOEC for linear alkylbenzene 

sulfonate in outdoor experimental streams. Environ. Toxicol. Chem. 

12:1763-1775. 

 Reliability: 2 Valid with restrictions 

(g) 

Type: Outdoor ponds. 

 Methods: Species or ecosystem studied: Outdoor ponds were used with three 

 compartments (700 L each) with sediment. Taxonomic groups tested were 

phytoplankton, plants, cyclopedia, and cladocerans. Two concentrations 

were tested with no duplicates. Test duration 56 days and one year. 

 Effects monitored: Population and community effects. 

 Chemical analysis: The substance was dosed according to need. 

 Results: For phytoplankton slight inhibition of photosynthesis and chlorophyll 

occurred at 5.0 mg/L. The best estimated NOEC was determined at slightly 

below 5 mg/L. 

 For plants reduction of species number and composition and for cladocerans 

inhibition of development occurred at the highest concentration tested. The 

best estimated NOEC for these groups was 5.0 mg/L. The best estimated 

LOEC was 10 mg/L. 

 For cyclopedia egg production was reduced at 5 mg/L. The best estimated 

NOEC was determined at 3.5 mg/L. The best estimated LOEC was 5 mg/L. 

 For midge no NOEC could be determined. Survival was strongly reduced 

due to low oxygen concentrations and a high level of suspended solids. 

 Substance: LAS; chain length is probably C12. 

 Remarks: A concentration-effect relationship was found. Concentrations were 

measured. Data as reported by BKH, Huls, and Henkel in IUCLID dataset 

for CAS #90194-45-9 dated 19 February 2000. 

 Reference: Huber, W., Zieris, F.J., Feind, D., and Neugebaur, K. 1987. 

Ecotoxicological evaluation of environmental chemicals by means of aquatic 

model ecosystems (Translation). Bundesministerium fuer Forschung und 

Technologie, Research Report (03-7314-0). 

 Reliability: 4 Not assignable. Original report not available for review.

 (h) 

 Type: Laboratory aquaria 
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 Methods: The effect of LAS on the structure and function of microbial communities 

was studied in a flow-through model ecosystem containing several trophic 

levels. The LAS was applied to 19-L glass aquaria in either well water 

(Phase I) or sewage effluent (Phase II). In Phase I, duplicate chambers 

contained water and 2.5 cm lake sediment (Winton Lake, Cincinnati, OH) 

and several trophic levels (bacteria, algae, macrophytes [Elodea 

canadensis,Lemna minor], macroinvertebrates [Daphnia magna, 

Paratanytarsus parthenogenica], and fish [Lepomis macrochirus]). 

Chambers were allowed to equilibrate for about four weeks and then were 

exposed to 0.5 and 5.0 mg/L LAS. Flow rate in the proportional diluter 

delivered 6 to 10 replacement volumes per day. In Phase II, the aquaria were 

supplied with LAS in sewage effluent to simulate more closely the situation 

in an actual receiving stream. Sewage effluent was generated in a 

continuous activated sludge (CAS) unit and was adjusted to maintain 50 

percent LAS degradation. Effluent from the CAS unit was then supplied to 

the test chambers at sewage dilutions of 3 and 30 percent to achieve nominal 

undegraded LAS concentrations of 0.5 and 5.0 mg/L, respectively. Test 

duration was 28 days. Microbial structure was estimated by measurements 

of total viable bacterial biomass as CFU/mL. Microbial function was 

estimated in Phase I by measuring the rates of oxygen consumption during 

the degradation of glucose and LAS. In Phase II, microbial function was 

assayed by radiochemical methods. 

 Results: In Phase I, the structure of microbial communities was not affected, and no 

significant differences were reported in mean biomass or number of colonyforming units between the microorganisms exposed at the two levels. The 

mean total biomass calculated for all tanks and across all sampling points was 

about 3 x 105

 CFU/mL. The function of the microbial communities was 

reduced only at 5.0 mg/L. In Phase II, no effect was seen on the structure of 

the microbial community, with mean CFU/mL in the low and high dose 

aquaria (0.9 x 105

 and 1.4 x 105, respectively) similar to the control aquaria 

(1.4 x 105

). Also, no effects were observed microbial function in Phase II, 

which was measured only as the degradation of LAS. Therefore, the NOEC 

based on the most sensitive endpoint (microbial community function) is 0.5 

mg/L. 

 Substance: LAS; radiolabeled C14-LAS with chain length C12 (91% purity) plus 

unlabeled LAS with average chain length C11.6 (C10 9.7%, C11 27.9%, C12

54.4%, C13 8.0%; 95% purity) 

 Remarks: Function assays in Phase II were based on LAS degradation only, since the 

Phase I results indicated that LAS degradation was the most sensitive 

indicator of toxic effect levels. 

 Reference: Larson, R.J. and Maki, A.W. 1982. Effect of linear alkylbenzene sulfonate 

on the structure and function of microbial communities in model ecosystems. 

Aquatic Toxicology and Hazard Assessment: Fifth Conference, ASTM STP 

766, Pearson, J.G., Foster, R.B., and Bishop, W.E., Eds., American Society 

for Testing and Materials, pp. 120-136. 

 Reliability: 2 Valid with restrictions 

 (i) 

 Type: Laboratory aquaria 

 Methods: Two exposures were conducted. Phase I was designed to develop basic 

toxicological information. Phase II introduced partially degraded LAS 

contained within the effluent of a continuous activated sludge unit and was 

designed to to simulate real-world fate and effects for LAS. In Phase I, 

duplicate 19-L glass aquaria containing model ecosystems at four nominal 

concentrations (0.5, 1.0, 2.0, 4.0 mg/L) contained water and 2.5 cm lake 

sediment (Winton Lake, Cincinnati, OH) and several trophic levels (bacteria, 
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UNEP PUBLICATIONS 244

algae, macrophytes [Elodea canadensis,Lemna minor], macroinvertebrates 

[Daphnia magna, Paratanytarsus parthenogenica], and fish [Lepomis 

macrochirus]). Flow rate in the proportional diluter delivered approximately 

8 replacement volumes per day. Additionally, at each cycle of the diluter, 

1.5 mL of a Daphnia food suspension diluted with a culture of Selenastrum

was added to each chamber. Following an initial 3 day acclimation period to 

analytically confirm test concentrations, 4 glass periphyton slides (5 x 5 cm), 

8 vegetative shoots of Elodea, 10 early instar Daphnia, 25 midge eggs and 5 

pre-weighred juvenile bluegills (2.5-5.0 cm length) were added to each 

aquarium. Fish were screened from access to the macroinvertebrates by a 60 

mesh stainless steel screen and were fed a daily supplement of frozen brine 

shrimp. In Phase II, the aquaria were supplied with LAS in sewage effluent 

to simulate more closely the situation in an actual receiving stream. Sewage 

effluent was generated in a continuous activated sludge (CAS) unit and was 

adjusted to maintain 50 percent LAS degradation. Effluent from the CAS 

unit was then supplied to the test chambers at continuous dilutions of 3.75, 

7.5, 15, and 30 percent sewage concentrations to simulate sewage dilutions 

existing in natural receiving waters. Test duration was 28 days. Effects 

monitored included population and community effects. Nominal 

concentrations were confirmed with MBAS analysis. 

 Results: Dissolved oxygen concentrations ranged between 7.0 and 9.0 mg/L during 

Phase I. Dissolved oxygen concentrations in Phase II ranged between 3.1 

and 7.3 mg/L, with the lowest readings consistently observed in the aquaria 

receiving the 30% sewage concentrations, as would be expected. 

Temperature was maintained at 2°C, mean pH was 8.1 ± 0.2 in Phase I and 

7.5 ± 0.3 in Phase II. MBAS analysis confirmed the nominal concentrations. 

 No significant effects on microbial community structure occurred in Phase I, 

with biomass levels in the high dose (4.0 mg/L) comparable to or greater than 

the biomass levels in the controls. Similarly, no significant effects on 

microbial community structure were observed in Phase II. The function of 

microbial communities in Phase I was affected at the high dose (4.0 mg/L), 

as evidenced by significant depression in the rates of both glucose and LAS 

degradation. No effects on microbial function were observed in Phase II. No 

dose response correlation in overall productivity was evident for the 

periphyton (aufwuchs) community in Phase I. In Phase II, the introduction of 

the sewage effluent produced a generally higher turbidity level and the higher 

organic concentrations were conducive to the growth of thick sheets of 

bacterial and fungal communities. Very little direct periphytic plant growth 

was observed. The stimulatory effect of the increasingly higher sewage 

concentration is evident in the progressively higher aufwuchs production 

observed between 3.75 and 30% effluent. No effects on Elodea production 

were observed in Phase I. However, in Phase II, Elodea and Lemna plant 

growth was inhibited at all concentrations except 3.75% by the increased 

bacterial and fungal periphyton growth as periphytic sheaths tended to cover 

the leaves and vegetative tips of the macrophytes. Evaluation of the Daphnia 

magna data from Phase I is confounded by unexpected poor control survival, 

although productivity appeared to be lower in the 1.0, 2.0 and 4.0 mg/L 

concentrations than at 0.5 mg/L. In Phase II, all Daphnia died in the 30% 

sewage concentration but production reached much greater numbers in the 

other concentrations than they did in Phase I. The midge species had an 

apparent reduction in numbers at 4.0 mg/L compared to the controls in Phase 

I. In Phase II, erratic growth in the controls and all exposures led to no 

meaningful midge survival at the end of Phase II. Bluegill fish growth at the 

end of Phase I was reduced at the 2.0 and 4.0 mg/L concentrations but not at 

0.5 or 1.0 mg/L. In Phase II, fish in all wastewater dilution concentrations 

from 3.75 to 30% grew less than the controls. The following table 
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UNEP PUBLICATIONS 245

summarizes the NOEC values (mg/L) for Phase I and Phase II, as determined 

from the data described above. 

Species Phase I Phase II 

Bacterial Structure 4.0 30% 

Bacterial Function 1.41a 30% 

Periphyton/Algae 4.0 3.75% 

Elodea 4.0 3.75% 

Duckweed (Lemna minor) Not Reported 3.75% 

Daphnia magna --b --c

Midge (Paratanytarsus 

parthenogenica) 2.0 --c

Bluegill (Lepomis macrochirus) 1.0 <3.75% 

 a Data available only for the low and high concentrations (0.5-4.0 mg/L). Value is geometric 

mean. 

 b Poor control survival precludes calculation of a NOEC. 

 c

 Data not interpretable 

 

 Therefore, the NOEC based on the most sensitive endpoint (bluegill growth) 

is 1.0 mg/L. 

 Substance: LAS; C14-LAS chain length C12 (91% purity) plus unlabeled LAS with 

average chain length C11.6 (C10 9.7%, C11 27.9%, C12 54.4%, C13 8.0%; 95% 

purity) 

 Reference: Maki, A.W. 1981. A laboratory model ecosystem approach to 

environmental fate and effects studies. Unpublished Internal Report, 

Environmental Safety Department Procter & Gamble Company, Cincinnati, 

Ohio. 

 Reliability: 2 Valid with restrictions 

 (j) 

 Type: In situ river exposures 

 Methods: Species or ecosystem studied: Test system was rectangular plexiglass plates 

(108 cm2

) suspended in river water. Plates were colonized with periphyton 

for four weeks before testing at locations above and below the Xenia sewage 

treatment plant outfall in the Little Miami River (Ohio). Studies below the 

outfall assessed the toxicity of LAS in the presence of 2030% treated 

municipal effluent. Colonized plates were then placed in five submerged 

plexiglass tubes (1 cm thick, 1 m long), which were then attached to an 

aluminium frame supported by rubber floats. LAS stock solutions were 

stored in 80-L polypropylene containers on the river bank and solutions were 

pumped daily at a delivery rate adjusted based on river flow to maintain four 

concentrations (0.2, 1.1, 9.8 and 28.1 mg/L) and a control. Duplicate set ups 

were used as replicates. Identical set ups were used above and below the 

outfall. 

 Test duration 21 days. 

 Effects monitored: Phytoplankton inhibition of photosynthesis and reduction 

of the number of taxa was determined. 

 Chemical analysis: Concentrations were measured. 

 Results: For inhibition of photosynthesis the best estimated NOEC and LOEC were 

9.8 and 28.1 mg/L respectively. At the highest concentration tested the 

number of taxa was not reduced. For this effect parameter the best estimated 

NOEC was >28.1 mg/L. 

 Substance: Dodecyl LAS (CAS #25155-30-3); average chain length C11.9; average 

molecular weight 346; C10 9%, C11 30%, C12 34%, C13 19%, C14 9% 

 Remarks: A concentration-effect relationship was found. Suspended solids were 

measured. 
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 Reference: Lewis, M.A., Pittinger, C.A., Davidson, D.H., and Ritchie, C.J. 1993. In situ

response of natural epiphyton to an anionic surfactant and an environmental 

safety assessment for phytotoxic effects. Environ. Toxicol. Chem. 12:1803-

1812. 

 Reliability: 2 Valid with restrictions 

(k) 

Type: Laboratory bottles/lake exposures 

 Methods: Species or ecosystem studied: Bottles (300 ml) filled with lake water were 

used as the test systems. Nine concentrations were tested in triplicate. 

 Once a month the bottles were suspended in a lake at 1 m depth for three 

hours. The experiment was repeated for six months. 

 Effects monitored: photosynthetic response of phytoplankton was 

determined. 

 Chemical analysis: Concentrations were measured. 

 Results: Mean EC50 values were 3.4 and 1.9 mg/L for C12 and C13, respectively. The 

ranges of EC50 values for the different tests were 0.5-8.0 and 0.2-8.1 mg/L 

for C12 and C13, respectively. 

 Substance: Dodecyl LAS; average chain length C11.8 (CAS #25155-30-3); and Tridecyl 

LAS, average chain length C13.3 (CAS #26248-24-8). 

 Remarks: A concentration-effect relationship was found. Suspended solids were not 

measured. The wide range of EC50 values is in part due to seasonal 

differences in temperature and community dynamics. 

 Reference: Lewis, M.A. and Hamm, B.G. 1986. Environmental modification of the 

photosynthetic response of lake plankton to surfactants and significance to a 

laboratory-field comparison. Water. Res. 20:1575-1582. 

 Reliability: 2 Valid with restrictions

4.8 BIOTRANSFORMATION AND KINETICS 

 (a) 

 Type: Animal [ ]; Aquatic [X]; Plant [ ]; Terrestrial [ ]; Other [ ]

 Methods: In a flow-through system a 21 day uptake and 14 day elimination experiment 

was conducted with Lepomis macrochirus. The LSC-measured exposure 

concentration was 0.5 mg/L (1.45 uM). Flow-through; water renewal rate: 

20 renewals per day; hardness as CaCO3 35 mg/L; pH 7.1; water/fish ratio: 

0.04 L/g. 

 Results: k1/k2 concentration factors were for muscle 36, liver 171, blood 237, carcass 

64, gall bladder 5224, gill and viscera 282 (on wet weight basis). 

 k2 values are almost the same (0.24-0.28 d-L) in all tissues but the liver. The 

value for the liver is double (0.48 d-L) of the other tissues. This indicates 

biotransformation in the liver. The value of kl in the gall bladder (1461 

L/kg/d) is at least 16 times higher than those in the other tissues (9-82 

L/kg/d). 

 t95 in the different tissues range between 150 and 300. 

 No information on metabolism was given. 

 Test Substance: Na-alkylbenzenesulfonate average chain length: C11.7 (C11 45%, C12 36.5%, 

C13 18.5%) radiolabeled material (14C uniformly labelled benzene ring) is 

spiked with unlabelled LAS (identical homologue composition), spiking ratio 

4:1 (unlabeled:14C labeled). 

 Remarks: Whole body concentration factors are reliable. Steady state attained within 

24 h. 

 Reference: Kimerle, R.A., Macek, K.J., Sleight, B.H., and Burrows, M.E. 1981. 

Bioconcentration of linear alkylbenzene sulfonates (LAS) in bluegill 

(Lepomis macrochirus). Water. Res. 15:251-256. 
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 Reliability: 2 Valid with restrictions 

 (b) 

 Type: Animal [ ]; Aquatic [X]; Plant [ ]; Terrestrial [ ]; Other [ ]

 Methods: Fathead minnows (Pimephales promelas) were exposed to LAS in a flowthrough system according to OECD guideline 305E. 

 Results: Steady state uptake was achieved by 96-h of exposure. Uptake constants (k1) 

range from 4.3 to 642.2 L/kg/day with C11 and C13 having the lowest and 

highest, respectively. The elimination rate constants (k2) range from 0.5 and 

1.5 days. k1 was dependent on hydrophobicity and alkyl chain length. k2 did 

not vary with hydrophobicity. 

 Reference: Tolls, J., Haller, M., De Graaf, I., Thijssen, M.A.T.C., and Sijm, D.T.H.M. 

1997. Bioconcentration of LAS: Experimental determination and 

extrapolation to environmental mixtures. 31:3426-3431. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Type: Animal [ ]; Aquatic [X]; Plant [ ]; Terrestrial [ ]; Other [ ]

 Method: In a flow-through system a 14 day uptake experiment was conducted with 

fish (Pimephales promelas). Two concentrations of 0.100 and 0.135 mg/L 

(0.3 and 0.4 uM) were tested resulting in concentration factors. Tissue 

extracts of the fish exposed to LAS were analysed by desulfonation-GC. 

Flow-through; water renewal rate: 3-4 renewals per day; no feeding; 

hardness 250 mg/L; well water. Chemical analyses by LSC. 

 Results: On the basis of the concentration in fish tissues (wet weight) and the two 

concentrations in water concentration factors in muscle were 4 and 3, and in 

the gall bladder 13,700 and 7,500. It remains unclear whether the observed 

variation of the concentration factors indicates a concentration dependence of 

bioaccumulation. The results indicate metabolic transformation, since the 

parent compound radioactivity could not account for all the radioactivity in 

the fish. Percentages of radioactivity accounted for by parent LAS in muscle 

50-70%, other organs 50-80%, gall bladder <1%. The authors report 

clearance of "substantially all 14C activity" within 3 days. 

 Test Substance: Linear LAS, chain length C12; uniformly 14C-labelled benzene ring, 2-phenylisomer-content: 17%. 

 Remarks: Steady state attained within 144 h. 

 Reference: Kimerle, R.A., Swisher, R.D., and Schroeder-Comotto, R.M. 1975. 

Surfactant structure and aquatic toxicity. Proc. IJC Symposium of Structure 

Activity Correlations in studies on toxicity and bioconcentration with aquatic 

organisms, pp. 22-35. 

 Reliability: 2 Valid with restrictions 

 

 (d) 

 Type: Animal [X]; Aquatic [ ]; Plant [ ]; Terrestrial [ ]; Other [ ]

 Methods: Fish (Ictalurus punctatus 250-450 g) were dosed with LAS via liquid gavage, 

gavage of food impregnated with LAS, and by intraperitoneal injection. 

Amount dosed: 425 ug (1.22 umole). Metabolism and elimination pathways 

were investigated. No aqueous exposure; metabolism chamber operated in a 

static mode; water was exchanged twice per day; 1 g of food, no feeding of 

the fish dosed by liquid gavage. Chemical analysis via LSC. 

 Results: Percentage eliminated from the different tissues 48 h after the end of the 24 

exposure period: 

 

Percent Eliminated: 

Gavage i.p. injection Food Fluid 
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Total 42 68 71 

Gills 4 49 33 

Urine 26 7 11 

Faeces+ Skin 12 12 27 

C02 <1 <1 <1 

 Test substance: Linear LAS, chain length C12; uniformly isomer distribution not specified. 

 Remarks: Elimination pathways for the three modes of dosing differed. As a 

considerable fraction of radiolabel administered via gavage is excreted via 

the gills it can be concluded that: 

a) LAS is resorbed readily in the GI-tract. 

b) The compounds excreted via the gills (LAS or its metabolites) are able to 

pass the gill membrane. 

 Reference: Schmidt, E.J. and Kimerle, R.A. 1981. New design and use of a fish 

metabolism chamber. In: Branson, D.R. and Dickson, K.L. (eds.). Aquatic 

Toxicology and Hazard Assessment: Fourth Conference, ASTM STP 737, 

436-448. 

 Reliability: 2 Valid with restrictions 

 

(e) 

 Type: Animal [ ]; Aquatic [X]; Plant [ ]; Terrestrial [ ]; Other [ ]

 Method: Fish (Cyprinus carpio 34.6 g) were exposed to combinations of LAS, 

 polyoxyethylene and sorbitan monooleate to assess the influence of these 

substances on the uptake of LAS. Exposure period was 3 h. Exposure 

concentration was 1 x 10-5 M LAS. LSC was used for tissue specific 

analysis, HPLC was used for measurement of gill adsorption. Dechlorinated 

tap water, filtered over active carbon; hardness 63 mg/L CaCO3; water/fish 

ratio: 0.14 g/L; no feeding during experiment. 

 Results: Concentration factors for specific tissues (measured by LSC) were for blood 

4.2, hepatopancreas 4.0, spleen 1.0, kidney 3.3, heart 1.7, brain 0.6, muscles 

0.2, gill 11, gall bladder 21. Adsorption of LAS to gills (Cgill/Cwater), 

measured by HPLC, isomer specific: 2-phenyl 16; 3-phenyl 5.4; 4-phenyl, 

2.6; 5- and 6-phenyl 1.9. 

 C12-LAS associated radiolabel is taken up by gills rapidly. It reaches the 

highest body level in the gall bladder after only three hours. The adsorption 

to the gills is related to the phenyl-substitution of the alkane. 

 The closer the benzenesulfonate-group is attached to the terminal carbon 

 atom of the alkyl chain, the higher the adsorption to the gills. As the gills are 

an important organ in the uptake of xenobiotic compounds, it seems 

reasonable to expect that those isomers which sorb strongly to the gills will 

also be taken up preferentially. 

 Test substance: Labelled linear LAS, isomer distribution not specified. (CAS #25155-30-3) 

 Remarks: No whole body concentration factors. 

 Reference: Toshima, S., Moriya, T., and Yoshimura, K. 1992. Effects of 

polyoxyethylene (20) sorbitan monooleate on the acute toxicity of linear 

 alkylbenzenesulfonate (C12-LAS) to fish. Ecotox. Environ. Saf. 24:26-36. 

 Reliability: 2 Valid with restrictions 

4.9 ADDITIONAL REMARKS 

(a) 

 Remarks: Pre-1993 published data and company owned aquatic toxicity test data are 

collected in a common data base (BKH, 1993). Statistical analysis showed: 

 -After removal of outliners, the dataset contains 586 records covering 93 

species. Algae, crustaceans and fish together make 68% of the 93 species. 
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Dominating species (genera) are: Scenedesmus, Selenastrum, Daphnia, 

Gammarus, Lepomis, Pimephales and Carassius (71% of the 586 records). 

34 of the 93 species are marine species. 

 -LAS does not have a specific mode of action for different species. The 

variability in the sensitivity between species is comparable to the variability 

within a species. 

 -The acute to chronic ratio is approximately a factor 5. 

 -The mean LC50 of all species is 5.5 mg/L. 

 -The mean NOEC (chronic) of all species is 0.8 mg/L. 

 -A quantitative structure activity relationship for chain length was determined 

for fish and crustaceans, longer chain lengths corresponding to higher 

toxicity. The bioavailability of adsorbed LAS molecules for aquatic 

organisms as midge larvae, daphnids and fish is assumed to be low, because 

observed toxicity thresholds in the presence of adsorbing material correspond 

to the calculated concentration of the fraction LAS dissolved and the toxicity 

data for the completely dissolved substance (Pittinger et al., 1989). 

 Reference: 1) BKH. 1993. The use of existing toxicity data for estimation of the 

Maximum Tolerable Environmental Concentration of Linear Alkyl Benzene 

Sulfonate, Part I: Main report; Part II: Data base. Study carried out for 

ECOSOL, BKH Consulting Engineers, Delft, NL. 

 2) Hand, V.C., Rapaport, R.A., Pittinger, C.A. 1990. First validation of a 

model for the adsorption of linear alkylbenzene sulfonate to sediment and 

comparison to chronic effects data. Chemosphere 21(6):741-750. 

 3) Pittinger, C.A., Woltering, D.M., and Masters, J.A. 1989. Bioavailability 

of sediment sorbed and aqueous surfactants to Chironomus riparius (midge). 

Environm. Toxicol. Chem. 8:1023-1033. 

 Reliability: 4 Not assignable 

 (b) 

 Results: Neither LAS nor its sulfophenylcarboxylate degradation products displayed 

any estrogenic effects. 

 Remarks: A recombinant yeast estrogen screen using Saccharomycea cerevisiae was 

employed to determine the potential estrogenic activity of LAS and its 

degradation products. 

 Reference: Routledge, E.J. and Sumpter, J.P. 1996. Estrogenic activity of surfactants 

and some of their degradation products assessed using a recombinant yeast 

screen. Environ. Toxicol. Chem. 15:241-248. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Type: Endocrine Disruption 

 Results: In the yeast screen, no statistical differences in absorbance were induced in 

any concentration of either of the three substances. In the hepatocyte assay, 

no increase in the concentration of Vg over the concentration of the controls 

was observed for LAS or any other three test substances. Results of both 

assays indicate that no estrogenic effects occurred after exposure to LAS or 

two of its biodegradation intermediates (SPC5 and SPC11). 

 Method: LAS, SPC5, or SPC11 were prepared in sterile distilled water and added to 

the culture media. Two in vitro screening assays for measurement of 

estrogenic activity were used: 1) the ER assay, with the recombinant yeast 

screen, and 2) the vitellogenin assay, with hepatocytes. ER was used as the 

positive control. Serial dilutions of the test compounds were used, with the 

maximum concentrations used in the hepatocytes assay were 150 μM (50 

mg/L) for LAS, 25 μM (7.4 mg/L) for SPC5, and 200 μM (72.8 mg/L) for 

SPC11. 

 Test Substance: 1) LAS-C11, 47% a.i., supplied by Petroquimica Espanola S.A. 
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 2) Sulfophenylcarboxylic acids (SPC5 and SPC11) (formed from successive 

oxidation of terminal methyl groups on the alkyl chain) 

 Reference: Navas, J.M., Gonzalez-Mazo, E., Wenzel, A., Gomez-Parra, A., and Segner, 

H. 1999. Linear alkylbenzene sulfonates and intermediate products from 

their degradation are not estrogenic. Marine Pollution Bulletin 38:880-884. 

 Reliability: 2 Valid with restrictions 

 (d) 

 Results: The final predicted no-effect concentration (PNEC) for C11.6 LAS was 250 

μg/L based on a single species PNEC of 320 μg/L and the range of field 

NOECs of 250-500 μg/L. All data values are expressed as dissolved 

concentrations. 

 Method: Predicted no-effect concentrations (PNECs) were derived for LAS and three 

other surfactants using three stages in an aquatic effects assessment. In the 

Initial stage, assessment factors are applied to available short-term toxicity 

data. In the Refined stage, statistical extrapolation based on long-term (i.e., 

chronic) toxicity data are employed. In the Comprehensive stage of effects 

assessment, a wide variety of laboratory and field model ecosystem studies 

are incorporated into the analysis. To determine the PNEC for LAS, all data 

types were compiled and evaluated. Since toxicity is related to carbon chain 

length, all data were normalized to LAS with a mean carbon chain length of 

11.6, the structure typically present in the environment based on the 

monitoring study described by Matthijs et al. 1999. 

 Remarks: For LAS, the predicted environmental concentrations (PECs) in the 

environment are about 50 to 100 times lower than the PNECs. This PNEC 

determination is part of an extensive monitoring program executed jointly by 

the Dutch Soap Association (NVZ) and the Dutch Ministry of Housing, 

Spatial Planning and the Environment (VROM). 

 Reference: van de Plassche, E.J., de Bruijn, J.H.M., Stephenson, R.R., Marshall, S.J., 

Feijtel, T.C.J., and Belanger, S.E. 1999. Predicted no-effect concentrations 

and risk characterization of four surfactants: Linear alkylbenzene sulfonate, 

alcohol ethoxylates, alcohol ethoxylated sulfates, and soap. Environmental 

Toxicology and Chemistry 18:2653-2663. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Results: A realistic worst-case estimation of the LAS concentration in sludgeamended soil is predicted to be 7 mg/kg dry weight, which is compared to the 

PNEC of 4.6 mg/kg. The LAS concentration will drop to a level below the 

PNEC within 6 to 24 days after sludge application, depending on the 

degradation rate of LAS. 

 Methods: LAS can be found in high concentrations in sewage sludge and may enter the 

soil compartment as a result of sludge application. To evaluate the effects 

and risk to soil organisms, a probabilistic (log-normal) distribution model 

was used to predict a no effect concentration (PNEC) for soil fauna, flora, 

and a combination of these. By extrapolation, the method determines a lower 

statistical tolerance limit. The preferred inputs to the current model are EC10

data from laboratory studies. By use of the log-normal distribution, a 

concentration (Kp) is found, for which the EC10 or NOEC values for 95% of 

all species in the community are greater. The value of Kp is used as the 

estimate of the PNEC. The soil concentration after sludge application was 

predicted by a number of scenarios and used as the predicted environmental 

concentration (PEC) in the risk characterization and calculation of risk 

quotients (RQ = PEC/PNEC). A LAS concentration of 4.6 mg/kg was used 

as the current best estimate of PNEC in all RQ calculations. The exposure 

scenarios included three levels of LAS contamination (530, 2,600 and 16,100 
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mg/kg), three half-lives (10, 25 and 40 days) and five different sludge loads 

(2, 4, 6, 8 and 10 t/ha). 

 Remarks: Even in the most extreme scenarios, the level of LAS is expected to be far 

below the estimated PNEC one year after application. 

 Test Substance: LAS (various, based on each study used) 

 Reference: Jensen, J., Lokke, H., Holmstrup, M., Krogh, P.H., and Elsgaard, L. 2001. 

Effects and risk assessment of linear alkylbenzene sulfonates in agricultural 

soil. 5. Probabilistic risk assessment of linear alkylbenzene sulfonates in 

sludge-amended soils. Environmental Toxicology and Chemistry 20:1690-

1697. 

 Reliability: 2 Valid with restrictions 
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5. TOXICITY 

5.1 ACUTE TOXICITY 

5.1.1 ACUTE ORAL TOXICITY 

(a) (Rat)

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: rat 

 Value: 1080 mg/kg bw 

 Method: OECD Guide-line 401 "Acute Oral Toxicity" 1981. Five male and five 

female rats were given LAS doses of 1075, 1220, 1360, 1710 or a control by 

gavage. Body weight and other signs were measured on days 7 and 14. 

Temperature was maintained at 20+

/-1oC with a 12 hr light-dark cycle. 

Animals were observed for 14 days after dosing. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 386 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; Activity: 86% 

 Remarks: Symptoms beginning about 30 minutes past application included diarrhea, 

squatting attitude, breathing difficulties, nose bleeding, ataxia, and lethargy. 

These symptoms had disappeared in surviving animals by 120 hours. 

Virtually all animals died in doses of 1220 mg/kg and above. Note that all 

doses are corrected for 86% activity. The original doses were 1250, 1415, 

1580 and 1990 mg/kg. 

 Reference: Murmann, P. 1984a. Akute orale Toxizitat von Marlon A 386 fur Ratten. 

Huels Report No. 0191. 

 Reliability: 2 Valid with restrictions

 (b) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: rat 

 Value: 1630 mg/kg bw 

 Method: OECD Guide-line 401 "Acute Oral Toxicity" 1981. Five male and five 

female rats were given LAS doses of 1260, 1580, 1785, and 1990 or a control 

by gavage. Body weight and other signs were measured on days 7 and 14. 

Temperature was maintained at 20+

/-1oC with a 12 hr light-dark cycle. 

Animals were observed for 14 days after dosing. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; Activity: 50% 

 Remarks: Symptoms beginning about 1-4 hours past application included diarrhea, 

squatting attitude, breathing difficulties, nose bleeding, ataxia, and lethargy. 

The symptoms in the lower doses disappeared with 24 to 48 hours. 

Symptoms disappeared in the 1785 mg/kg dose and higher within 8 days. 

Virtually all animals died in doses of 1785 mg/kg and above. Note that all 

doses are corrected for 50% activity. The original doses were 2510, 3160, 

3570 and 3980 mg/kg. 

 Reference: Murmann, P. 1984c. Akute orale Toxizitat von Marlon A 350 fur Ratten. 

Huels Report No. 209. 

 Reliability: 2 Valid with restrictions

 (c) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: rat 

 Value: 1410 mg/kg bw 
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 Method: OECD Guide-line 401 "Acute Oral Toxicity" 1981. Five male and five 

female rats were given LAS doses of 1190, 1500 and 1890 or a control by 

gavage. Body weight and other signs were measured on days 7 and 14. 

Temperature was maintained at 20+

/-1oC with a 12 hr light-dark cycle. 

Animals were observed for 14 days after dosing. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 330 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; Activity: 30%. 

 Remarks: Symptoms beginning about 90 minutes past application included diarrhea, 

squatting attitude, breathing difficulties, nose bleeding, ataxia, and lethargy. 

These symptoms had disappeared in surviving animals by 72 hours. 

Virtually all animals died in doses of 1500 mg/kg and above. Note that all 

doses are corrected for 30% activity. The original doses were 3980, 5010 

and 6310 mg/kg. 

 Reference: Murmann, P. 1984a. Akute orale Toxizitat von Marlon A 330 fur Ratten. 

Huels Report No. 0186. 

 Reliability: 2 Valid with restrictions

 (d) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: rat 

 Value: LD50 for male animals: 1460 mg/kg 

 LD50 for female animals: 1470 mg/kg 

 Method: Male and female rats were given a single dose of LAS by gavage and 

observed for mortality. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

<C10 0.1%, C10 10.1%, C11 33.7%, C12 31%, C13 25.1%.; average alkyl chain 

length = C11.7; activity: 99.5% 

 Remarks: Information as reported in IPCS document. 

 Reference: Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M., and Fukushima, A. 1978. Acute, subacute and 

chronic toxicity of magnesium linear alkylbenzene sulfonate (LAS-Mg). J. 

Med. Soc. Toho, Japan. 25 (5-6):850-875 (in Japanese). Referenced in 

IPCS, Environmental Health Criteria 169. Linear Alkylbenzene Sulfonates 

and Related Compounds, WHO. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document, therefore it is considered to be 

reliable. 

 (e) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: Rat, CFY (Sprague-Dawley origin); male and female 

 Value: 1980 mg/kg bw 

 Method: OECD Guideline 401. Five male and five female rats were given single 

doses by gavage at 1500, 2350 and 3760 mg/kg bw. Rats were housed in 

cages grouped by sex and given standard laboratory diet and water ad 

libitum. Mean daily temperature was maintained at 21-22o

C at a mean 

relative humidity of 56%. Lighting was on a 12 hrs dark and 12 hrs light 

photoperiod. Animals were observed for 14 days after dosing. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Alkylbenzene sulfonate, sodium salt (designated as P-500 N-Na). Activity 

47%. Average alkyl chain length = C11.2 Clear yellow liquid. 

 Remarks: Four rats from each of the two lowest concentrations and all rats from the 

highest concentration died. All deaths occurred between 6 and 23 hours after 
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dosing. Signs of reaction to treatment included pilo-erection, hunched 

posture, abnormal gait (waddling), lethargy, decreased respiratory rate, 

ptosis, pallor of the extremities, and diarrhea. All surviving animals 

appeared to recover completely by day 4. Autopsy of rats that died revealed 

isolated cases of pallor of the kidneys or spleen. Terminal necropsy findings 

for survivors were normal. Note that all doses are corrected for 47% activity. 

The original doses were 3200, 5000, and 8000 mg/kg. 

 Reference: Kynoch, S.R. 1986a. Acute oral toxicity to rats: P-500 N-Na. Huntingdon 

Research Cener Report. No. 86546D/PEQ 7/AC. 

 Reliability: 1 Valid without restriction

 

 (f) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: Sprague-Dawley strain albino male and female rats 

 Value: 1320 mg/kg (lower limit: 1220 mg/kg; upper limit: 1430 mg/kg) 

 Method: Acute Oral Minimal Lethal Dose Test 

 The test substance was applied as a 20% aqueous solution by stomach tube to 

Sprague-Dawley strain albino male and female rats. After the approximate 

LD50 was determined, groups of male and female rats were fed in increasing 

doses at increments of 0.1 fractional log intervals at three levels (1000, 1260 

and 1580 mg/kg) designed to blanket the toxicity range thereby supplying 

data for calculation of the LD50 which was performed according to the 

method of E.J. de Beer. Observations of toxic signs were recorded and the 

viscera of the test animals were examined macroscopically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-225); C9 1%; C10 7%, C11

25%, C12 48%, C13 19%, C14 1%; average alkyl chain length = C11.9. 

 Remarks: The compound was classified as mildly toxic by oral ingestion in male and 

female rats. All rats at 1000 mg/kg and 4 of 5 rats at 1260 mg/kg survived. 

Survival time was one to two days for rats that died at 1580 mg/kg. The 

toxic signs included reduced appetite and activity (one to two days in 

survivors), diarrhoea, increasing weakness, collapse, and death. The autopsy 

revealed hemorrhagic lungs, liver discoloration, and acute gastrointestinal 

inflammation. Surviving animals were sacrificed seven days after dosing. In 

these animals the vircera appeared normal by macroscopic examination. 

 Reference: Monsanto Company. 1971. Linear alkylbenzene sodium sulfonate – 

Alkylate 225 Lot CC 6450 – Acute toxicity screen. Project No. Y-71-119. 

Unpublished report. 

 Reliability: 2 Valid with restrictions

 (g) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: Sprague-Dawley strain albino male and female rats 

 Value: 1430 mg/kg (lower limit: 1300 mg/kg; upper limit: 1570 mg/kg) 

 Method: Acute Oral Minimal Lethal Dose Test 

 The test substance was applied as a 10% aqueous solution by stomach tube to 

Sprague-Dawley strain albino male and female rats. After the approximate 

LD50 was determined, groups of male and female rats were fed in increasing 

doses at increments of 0.1 fractional log intervals at four levels (1000, 1260, 

1580 and 2000 mg/kg) designed to blanket the toxicity range thereby 

supplying data for calculation of the LD50 which was performed according to 

the method of E.J. de Beer. Observations of toxic signs were recorded and 

the viscera of the test animals were examined macroscopically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-215); C9 1%, C10 16%, C11

43%, C12 40%, C13 1%, C14 <1%; average alkyl chain length = C11.35. 
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 Remarks: The compound was classified as mildly toxic by oral ingestion in male and 

female rats. All rats survived at 1000 mg/kg. Three of 5 and 2 of 5 survived 

1260 and 1580, respectively. Survival time was sixteen hours to two days in 

the rats that died. The toxic signs included reduced appetite and activity (two 

to three days in survivors), increasing weakness, slight tremors, collapse, and 

death. The autopsy revealed lung and liver hyperaemia and gastrointestinal 

inflammation. Surviving animals were sacrificed seven days after dosing. In 

these animals the vircera appeared normal by macroscopic examination. 

 Reference: Monsanto Company. 1972a. Linear alkylbenzene sodium sulfonate – 

Alkylate 215 Lot CC 6772S – Acute toxicity screen. Project No. Y-72-274. 

Unpublished report. 

 Reliability: 2 Valid with restrictions

 (h) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: Sprague-Dawley strain albino male and female rats 

 Value: 1360 mg/kg (lower limit: 1240 mg/kg; upper limit: 1500 mg/kg) 

 Method: Acute Oral Minimal Lethal Dose Test 

 The test substance was applied as a 10% aqueous solution by stomach tube to 

Sprague-Dawley strain albino male and female rats. After the approximate 

LD50 was determined, groups of male and female rats were fed in increasing 

doses at increments of 0.1 fractional log intervals at four levels (1000, 1260, 

1580 and 2000 mg/kg) designed to blanket the toxicity range thereby 

supplying data for calculation of the LD50 which was performed according to 

the method of E.J. de Beer. Observations of toxic signs were recorded and 

the viscera of the test animals were examined macroscopically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-222L); average alkyl 

chain length = C11.5

 Remarks: The compound was classified as slightly toxic by oral ingestion in male and 

female rats. Survival time was sixteen hours to three days in the rats that 

died. The toxic signs included reduced appetite and activity (one to three 

days in survivors), increasing weakness, collapse, and death. The autopsy 

revealed lung and liver hyperaemia and gastrointestinal inflammation. 

Surviving animals were sacrificed seven days after dosing. In these animals 

the vircera appeared normal by macroscopic examination. 

 Reference: Monsanto Company. 1972b. Linear alkylbenzene sodium sulfonate – 

Alkylate 222L Lot CC 6773S – Acute toxicity screen. Project No. Y-72-275. 

Unpublished report. 

 Reliability: 2 Valid with restrictions

 (i) (Mouse)

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: mouse 

 Value: LD50 male animals: 2160 mg/kg 

 LD50 female animals: 2250 mg/kg 

 Method: Male and female mice were given a single dose of LAS and observed for 

mortality. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3). 

<C10 0.1%, C10 10.1%, C11 33.7 %, C12 31%, C13 25.1%; average alkyl chain 

length = C11.7; activity: 99.5% 

 Remarks: Information as cited in IPCS document. 

 Reference: Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M., and Fukushima, A. 1978. Acute, subacute and 

chronic toxicity of magnesium linear alkylbenzene sulfonate (LAS-Mg). J. 
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Med. Soc. Toho, Japan. 25 (5-6):850-875 (in Japanese). Referenced in 

IPCS, Environmental Health Criteria 169. Linear Alkylbenzene Sulfonates 

and Related Compounds, WHO. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

5.1.2 ACUTE INHALATION TOXICITY

 Type: LC0 [ ]; LC100 [ ]; LC50 [ ]; LCL0 [ ]; Other [X] Approximate lethal 

concentration (ALC) 

 Species/strain: Rat/Male Crl: CD (SD) BR 

 Exposure time: single 4-hour period 

 Value: 310 mg/m3

 of particulate 

 Method: Groups of six male 8-week old rats were restrained in perforated, stainless 

steel cylinders with conical nose pieces. Exposure was nose-only to an 

aerosol atmosphere for 4 hours. After exposure, rats were returned to their 

cages and observed for clinical signs for 14 days. Mean measured 

concentrations in the test chambers were 65, 120, 260, and 310 mg/m3

. 

Chamber temperature ranged between 25-26o

C. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: LAS (CAS #25155-30-0); activity 98% 

 Remarks: The ALC is defined as the lowest atmospheric concentration generated that 

caused death in 1 or more rats either on the day of exposure or within 14 days 

post exposure. No mortality occurred at concentrations up to 260 mg/m3

. At 

310 mg/m3

, one rat died during exposure and 2 rats died one day post 

exposure. The test material is considered moderately toxic by inhalation. 

However, it is important to note that this laboratory exposure is not 

representative of the possible LAS exposure during actual use. In this 

study, animals were given high exposures to respirable-sized particles 

(MMAD at 310 mg/m3

 = 2.5 microns). Spray products containing LAS are 

designed to produce large particle sizes. These large particles are needed 

for efficient delivery of the spray to the surface being cleaned. This results 

in particle sizes that are much larger than the respirable particle sizes used 

in testing and therefore would not be able to reach far into the lungs where 

effects could occur. Given this lack of relevance to real-world exposure 

potential, the use of this study for risk assessment purposes is limited. 

 Reference: Kinney, L.A. 1985. Approximate lethal concentrations (ALCs) by 

inhalation of sodium lauryl sulfate & sodium dodecylbenzene sulfonate. 

Dupont Haskell Laboratory Report No. 474-84. 

 Reliability: 2 Valid with restrictions

5.1.3 ACUTE DERMAL TOXICITY

 (a) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ]

 Species: Rat, CFY (Sprague-Dawley origin); male and female 

 Value: >2000 mg/kg bw 

 Method: OECD Guideline 402. Five male and five female rats were exposed to 2000 

mg/kg in a limit test. The test substance was applied to clipped intact skin in 

the dorso-lumbar region and covered with gauze held in place with an 

impermeable dressing. The dressing was removed after 24 hours and the 

treated area of the skin washed with warm water and blotted dry. 

Observations for dermal irritation were made daily for 14 days. 
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 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Alkylbenzene sulfonate, sodium salt (designated as P-500 N-Na). activity 

47%. Average alkyl chain length = C11.2. Yellow, viscous liquid. 

 Remarks: There were no deaths or signs of a systemic reaction following a single 

dermal application at 2000 mg/kg bw. Well defined or slight erythema and 

slight oedema were observed at all test sites after removal of the occlusive 

dressing on Day 2. All test sites were entirely covered by scab formation 

from Day 7. Sloughing from the scabbed skin began at various times 

between Day 7 and Day 12 and was completed before termination. Low 

bodyweight gains or loss of body weight were recorded for one male and 

three females in Day 8. Two of the same females and a third female also 

showed low bodyweight gain between Days 8 and 15. 

 Reference: Kynoch, S.R. 1986b. Acute dermal toxicity to rats of P-500 N-Na. 

Huntingdon Research Center. Report No. 86718D/PEQ 8/AC. 

 Reliability: 1 Valid without restriction

 (b) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: New Zealand white rabbit 

 Value: > 200 mg/kg and < 316 mg/kg 

 Method: Acute Skin Absorption Minimal Lethal Dose Test 

 The test substance was applied as a 30% aqueous solution and the doses of 

the solution administered were 126, 200, 316, 501, 794, 1260, 2000, 3160 

and 5010 mg/kg. The doses were administered to a closely clipped area of 

intact skin of male and female rabbits (1 animal/dose). The treated areas 

were covered with plastic strips and the animals were placed in wooden 

stocks for up to twenty-four hours. After the twenty-four hours the animals 

were assigned to individual cages. Observations of toxic signs were recorded 

daily and the viscera of the test animals were examined macroscopically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-225; C9 1%; C10 7%, C11

25%, C12 48%, C13 19%, C14 1%; average alkyl chain length = C11.9) 

 Remarks: The test substance was classified as moderately toxic. Animals exposed 

dermally to 126 and 200 mg/kg survived for the 14 day study duration. 

Survival time for animals receiving all other doses ranged from two to eight 

days. The toxic signs included reduced appetite and activity, increasing 

weakness, collapse and death. The autopsy revealed hemorrhagic lungs, liver 

discoloration, enlarged gall bladder, and gastrointestinal inflammation. The 

animals that survived were sacrificed fourteen days after dosing. In these 

animals the viscera appeared normal by macroscopic examination. 

 Reference: Monsanto Company. 1971. Linear alkylbenzene sodium sulfonate – 

Alkylate 225 Lot CC 6450 – Acute toxicity screen. Project No. Y-71-119. 

Unpublished report. 

 Reliability: 4 (insufficient animals per dose of mixed sex, etc.) 

 (c) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: New Zealand white rabbit 

 Value: > 631 mg/kg and < 1000 mg/kg 

 Method: Acute Skin Absorption Minimal Lethal Dose Test 

 The test substance was applied as a 20% aqueous solution and the doses of 

the solution administered were 200, 316, 631, 1000, 1260, 2000 and 3160 

mg/kg. The doses were administered to a closely clipped area of intact skin 

of male and female rabbits (1 animal/dose). The treated areas were covered 

with plastic strips and the animals were placed in wooden stocks for up to 

twenty-four hours. After the twenty-four hours the animals were assigned to 
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individual cages. Observations of toxic signs were recorded daily and the 

viscera of the test animals were examined macroscopically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-215; C9 1%, C10 16%, C11

43%, C12 40%, C13 1%, C14 <1%; average alkyl chain length = C11.35) 

 Remarks: The test substance was classified as moderately toxic. Survival time ranged 

from one to two days. The toxic signs included reduced appetite and activity, 

increasing weakness, collapse and death. The autopsy revealed lung 

hyperemia, areas of liver discoloration and gastrointestinal inflammation. 

The animals that survived were sacrificed fourteen days after dosing. In 

these animals the viscera appeared normal by macroscopic examination. 

 Reference: Monsanto Company. 1972a. Linear alkylbenzene sodium sulfonate – 

Alkylate 215 Lot CC 6772S – Acute toxicity screen. Project No. Y-72-274. 

Unpublished report. 

 Reliability: 4 (insufficient animals per dose of mixed sex, etc.) 

 (d) 

 Type: LD0 [ ]; LD100 [ ]; LD 50 [X]; LDL0 [ ]; Other [ ] 

 Species/strain: New Zealand white rabbit 

 Value: > 631 mg/kg and < 1000 mg/kg 

 Method: Acute Skin Absorption Minimal Lethal Dose Test 

 The test substance was applied as a 20% aqueous solution and the doses of 

the solution administered were 200, 398, 631, 1000, 1260, 2000 and 3160 

mg/kg. The doses were administered to a closely clipped area of intact skin 

of male and female rabbits (1 animal/dose). The treated areas were covered 

with plastic strips and the animals were placed in wooden stocks for up to 

twenty-four hours. After the twenty-four hours the animals were assigned to 

individual cages. Observations of toxic signs were recorded daily and the 

viscera of the test animals were examined macroscopically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-222L; average alkyl chain 

length = C11.5) 

 Remarks: The test substance was classified as moderately toxic. Survival time was two 

days. The toxic signs were reduced appetite and activity, increasing 

weakness, collapse and death. The autopsy revealed lung hyperemia, areas 

of liver discoloration and gastrointestinal inflammation. The animals that 

survived were sacrificed fourteen days after dosing. In these animals the 

viscera appeared normal by macroscopic examination. 

 Reference: Monsanto Company. 1972b. Linear alkylbenzene sodium sulfonate – 

Alkylate 222L Lot CC 6773S – Acute toxicity screen. Project No. Y-72-275. 

Unpublished report. 

 Reliability: 4 (insufficient animals per dose of mixed sex, etc.) 

5.1.4 ACUTE TOXICITY, OTHER ROUTES OF ADMINISTRATION 

 

 (a) 

 Type: LD0 [ ]; LD100 [ ]; LD50 [X]; LDL0 [ ]; Other [ ]

 Species/strain: rat 

 Administration: i.m. [ ]; i.p. [ ]; i.v. [ ]; infusion [ ]; s.c. [X]; other [ ]

 Value: Females = 810 mg/kg; males = 840 mg/kg bw 

 Method: Rats were given subcutaneous injections of LAS 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

<C10 0.1%, C10 10.1%, C11 33.7 %, C12 31%, C13 25.1%; average alkyl chain 

length = C11.7; activity: 99.5% 
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 Remarks: Information as cited in IPCS document. 

 Reference: Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M., and Fukushima, A. 1978. Acute, subacute and 

chronic toxicity of magnesium linear alkylbenzene sulfonate (LAS-Mg). J. 

Med. Soc. Toho, Japan. 25 (5-6):850-875 (in Japanese). Referenced in 

IPCS, Environmental Health Criteria 169. Linear Alkylbenzene Sulfonates 

and Related Compounds. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (b) 

 Type: LD0 [ ]; LD100 [ ]; LD50 [X]; LDL0 [ ]; Other [ ]

 Species/strain: mouse 

 Administration: i.m. [ ]; i.p. [ ]; i.v. [ ]; infusion [ ]; s.c. [X]; other [ ]

 Value: Females = 1400 mg/kg; males = 1250 mg/kg bw 

 Method: Mice were given subcutaneous injections of LAS. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

<C10 0.1%, C10 10.1%, C11 33.7 %, C12 31%, C13 25.1%; average alkyl chain 

length = C11.7; activity: 99.5% 

 Remarks: Information as cited in IPCS document. 

 Reference: Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M., and Fukushima, A. 1978. Acute, subacute and 

chronic toxicity of magnesium linear alkylbenzene sulfonate (LAS-Mg). J. 

Med. Soc. Toho, Japan. 25 (5-6):850-875 (in Japanese). Referenced in 

IPCS, Environmental Health Criteria 169. Linear Alkylbenzene Sulfonates 

and Related Compounds. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (c) 

 Type: LD0 [ ]; LD100 [ ]; LD50 [X]; LDL0 [ ]; Other [ ]

 Species/strain: rat 

 Administration: i.m. [ ]; i.p. [ ]; i.v. [X]; infusion [ ]; s.c. [ ]; other [ ]

 Value: Females = 126 mg/kg; males = 119 mg/kg bw 

 Method: Rats were given intravenous injections of LAS. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

 <C10 0.1%, C10 10.1%, C11 33.7 %, C12 31%, C13 25.1%; average alkyl chain 

length = C11.7; activity: 99.5% 

 Remarks: Information as cited in IPCS document. 

 Reference: Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M., and Fukushima, A. 1978. Acute, subacute and 

chronic toxicity of magnesium linear alkylbenzene sulfonate (LAS-Mg). J. 

Med. Soc. Toho, Japan. 25 (5-6):850-875 (in Japanese). Referenced in 

IPCS, Environmental Health Criteria 169. Linear Alkylbenzene Sulfonates 

and Related Compounds. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (d) 

 Type: LD0 [ ]; LD100 [ ]; LD50 [X]; LDL0 [ ]; Other [ ]

 Species/strain: mouse 
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 Administration: i.m. [ ]; i.p. [ ]; i.v. [X]; infusion [ ]; s.c. [ ]; other [ ]

 Value: Females = 298 mg/kg; males = 207 mg/kg bw 

 Method: Mice were given intravenous injections of LAS. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

 <C10 0.1%, C10 10.1%, C11 33.7 %, C12 31%, C13 25.1%; average alkyl chain 

length = C11.7; activity: 99.5% 

 Remarks: Information as cited in IPCS document. 

 Reference: Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M., and Fukushima, A. 1978. Acute, subacute and 

chronic toxicity of magnesium linear alkylbenzene sulfonate (LAS-Mg). J. 

Med. Soc. Toho, Japan. 25 (5-6):850-875 (in Japanese). Referenced in 

IPCS, Environmental Health Criteria 169. Linear Alkylbenzene Sulfonates 

and Related Compounds. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (e) 

 Type: LD0 [ ]; LD100 [ ]; LD50 [X]; LDL0 [ ]; Other [ ]

 Species/strain: mouse, albino, Harlan strain 

 Administration: i.m. [ ]; i.p. [ ]; i.v. [X]; infusion [ ]; s.c. [ ]; other [ ]

 Exposure time: 24 hours 

 Value: 105 mg/kg bw (C12 LAS); 115 mg/kg bw (C10 LAS) 

 Method: Mice in groups of 10 were given intravenous injections of C10 or C12 LAS. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C12 LAS homologue; C10 LAS homologue 

 Remarks: Varying doses were given with an increasing increment between doses of 

20% or less. 

 Reference: Hopper, S.S., Hulpieu, H.R. and Cole, V.V. 1949. Some toxicological 

properties of surface active agents. J. Am. Pharmacol. Assoc. 38:428-432. 

 Reliability: 2 Valid with restrictions 

5.2 CORROSIVENESS/IRRITATION 

5.2.1 SKIN IRRITATION/CORROSION 

(a) 

Species: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ]; Moderate to severe irritating [X]

Method: OECD Guideline 404. A 0.5 ml aliquot of P-500 N-Na was applied under a 

2.5 cm2

 gauze pad to an approximate 10 cm2 area of clipped intact skin of 3 

rabbits. Each treatment site was occluded with an elastic adhesive dressing 

for four hours, after which the dressing was removed and the area washed 

with distilled water. Examination of the treated skin was made 

approximately 30 minutes after removal of the patch and daily through 14 

days. Grading and scoring of the dermal reactions was performed using the 

standard numerical scoring system. 

GLP: Yes [X] No [ ] ? [ ]

Test substance: Alkylbenzene sulfonate, sodium salt (designated as P-500 N-Na). Activity 

47%. Average alkyl chain length = C11.2. Clear yellow liquid. 

Remarks: Well defined to moderate skin reactions were observed in all three animals 

following removal of the bandages. Desquamation of the stratum corneum 
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was observed in all three animals. The reaction in all three animals gradually 

ameliorated from Days 5, 10 and 11, respectively, and had all resolved 

completely in one animal by Day 12. 

Reference: Liggett, M.P. and Parcell, B.I. 1986a. Irritant effects on rabbit skin of P-500 

N-Na. Huntingdon Research Center. Report No. 86400D/PEQ 9/SE. 

Reliability: 1 Valid without restriction 

(b) 

Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Method: OECD Guideline 404. A single dose of 0.5 g was applied to the clipped 

intact skin of six rabbits and secured with a gauze pad covered by an 

impermeable covering. The patch was removed after a 4 hour exposure and 

the site washed with water. Animals were examined for signs of erythema 

and oedema and the responses scored at 60 minutes, 24, 48 and 72 hr, and 

daily as needed up to 7 days. Skin irritation was scored using the standard 

rating system and averaged. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS activity 50%; average alkyl chain length = C11.6

 Remarks: Average score after 72 hours were 2.4 and 2.83 for erythema and oedema, 

respectively. 

 Reference: Biolab SGS. 1989a. Primary skin irritation. Report No. T00428/4. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Species/strain: rabbit 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Highly corrosive (causes severe burns) [ ]; 

 Corrosive (causes burns) [ ]; Irritating [X]; Not irritating [ ]

 Method: OECD Guide-line 404 "Acute Dermal Irritation/Corrosion" 1984 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: C10 LAS (CAS #1322-98-1) and C12 LAS (CAS #25155-30-0). 

 Remarks: Reference reports the results of many experiments conducted on LAS and 

other surfactants. 

 Reference: Kaestner, W. 1997. Local tolerance (animal tests): mucous membranes and 

skin. In: Anionic Surfactants: Biochemistry, Toxicology, Dermatology. 2nd

Edition. 

 Reliability: 4 Not assignable 

 (d) 

 Species/strain: rabbit 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Highly corrosive (causes severe burns) [ ]; 

 Corrosive (causes burns) [ ]; Irritating [X]; Not irritating [ ]

 Method: OECD Guide-line 404 "Acute Dermal Irritation/Corrosion" 1981. Three 

male and female rabbits received 0.5 ml of 50% active material to the shaved 

intact skin. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS # 68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; activity: 50%. 
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 Remarks: Mean irritation index: 5.1 out of 8. Individual scores: edema: 2.28, 

erythema: 3.0 

 Reference: Murmann, P. 1983a. Prufung der akuten Hautreizwirkung von Marlon A 

350. Huels Report No. 0171. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderately irritating [X]; Slightly irritating [ ]; 

 Not irritating [ ]

 Method: OECD Guideline 404. A single dose of 0.5 g was applied to the clipped 

intact skin of six rabbits and secured with a gauze pad covered by an 

impermeable covering. The patch is removed after a 4 hour exposure and the 

site washed with water. A second site with the skin abraded received the 

same treatment. Animals are examined for signs of erythema and oedema 

and the responses scored at 60 minutes, 24, 48 and 72 hr, and daily as needed 

up to 7 days. Skin irritation is scored using the standard rating system and 

averaged. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (made from Sirene LAB); activity 5%; average alkyl chain length = 

C11.6

 Remarks: Average scores after 72 hours were 1.67 and 2.17 for erythema and oedema, 

respectively. The primary irritation index was calculated to be 3.82, which 

classifies 5% LAS as a moderate skin irritant. No differences were observed 

between intact and abraded skin. 

 Reference: Biolab SGS. 1989b. Primary skin irritation. Report No. T343. 

 Reliability: 2 Valid with restrictions 

 (f) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [X]

 Method: OECD Guideline 404. A single dose of 0.5 g was applied to the clipped 

intact skin of six rabbits and secured with a gauze pad covered by an 

impermeable covering. The patch is removed after a 4 hour exposure and the 

site washed with water. A second site with the skin abraded received the 

same treatment. Animals are examined for signs of erythema and oedema 

and the responses scored at 60 minutes, 24, 48 and 72 hr, and daily as needed 

up to 7 days. Skin irritation is scored using the standard rating system and 

averaged. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (made from Sirene LAB); activity 2.5%; average alkyl chain length = 

C11.6

 Remarks: No signs of irritation were observed during the study. 

 Reference: Biolab SGS. 1989c. Primary skin irritation. Report No. T00430/2. 

 Reliability: 2 Valid with restrictions 

 (g) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [X]

 Method: OECD Guideline 404. A single dose of 0.5 g was applied to the clipped 

intact skin of six rabbits and secured with a gauze pad covered by an 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 263

impermeable covering. The patch is removed after a 4 hour exposure and the 

site washed with water. A second site with the skin abraded received the 

same treatment. Animals are examined for signs of erythema and oedema 

and the responses scored at 60 minutes, 24, 48 and 72 hr, and daily as needed 

up to 7 days. Skin irritation is scored using the standard rating system and 

averaged. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (made from Sirene LAB); activity 1%; average alkyl chain length = 

C11.6

 Remarks: No signs of irritation were observed during the study. 

 Reference: Biolab SGS. 1983. Primary skin irritation. Report No. T116/2. 

 Reliability: 2 Valid with restrictions 

 (h) 

 Species/strain: albino male and female rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [X]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Highly corrosive (causes severe burns) [ ]; 

 Corrosive (causes burns) [ ]; Irritating [X]; Not irritating [ ]

 Method: The clipped, intact and abraded skin of six albino male and female rabbits 

was exposed to 0.5 g of finely ground sample moistened with water under a 

one inch by one inch square patch, two single layers thick. The patches were 

positioned in place with adhesive tape. The trunk of each animal was 

wrapped with plastic strips to avoid contamination and retard evaporation for 

the 24 hour exposure period. Observations were made over a period of seven 

days for irritation. The data was scored according to the method of Draize, 

et al. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-225); C9 1%, C10 7%, C11

25%, C12 48%, C13 19%, C14 1%; average alkyl chain length = C11.9

 Remarks: Primary Irritation Score: 6.2 

 Intact Skin: 6.8/8 

 Abraded Skin: 6.8/8 

 Slight to moderate erythema and edema were present after 24 hours. These 

symptoms persisted through 120 hours. The compound was classed as a 

primary skin irritant under the grading system as outlined in the Federal 

Hazardous Substance Act. The sample had a defatting effect on the skin 

causing the skin to slough off in ten to fourteen days. There was no injury in 

depth. 

 Reference: Monsanto Company. 1971. Linear alkylbenzene sodium sulfonate – 

Alkylate 225 Lot CC 6450 – Acute toxicity screen. Project No. Y-71-119. 

Unpublished report. 

 Reliability: 2 Valid with restrictions 

 (i) 

 Species/strain: New Zealand white male and female rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [X]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Highly corrosive (causes severe burns) [ ]; 

 Corrosive (causes burns) [ ]; Irritating [X]; Not irritating [ ]

 Method: The clipped, intact and abraded skin of three New Zealand white male and 

female rabbits was applied with 0.5 g of finely ground sample moistened 

with water under a one inch by one inch square patch, two single layers 

thick. The patches were positioned in place with adhesive tape. The trunk of 
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each animal was wrapped with plastic strips to avoid contamination and 

retard evaporation for the 24 hour exposure period. Observations were made 

over a period of seven days for irritation. The data was scored according to 

the method of Draize, Woodard and Calvery (Journal of Pharm. and Exp. 

Therapeutics, Volume 82, December 1944). 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-215); C9 1%, C10 16%, C11

43%, C12 40%, C13 1%, C14 <1%; average alkyl chain length = C11.35

 Remarks: Moderate to severe erythema and edema were present after 24 hours. These 

symptoms persisted through 120 hours. The average maximum score was 

7.3 out of a possible 8 at 24 hours. The compound was classed as a severe 

skin irritant. The sample had a defatting effect on the skin causing the skin to 

slough off in ten to fourteen days. There was no injury in depth. 

 Reference: Monsanto Company. 1972a. Linear alkylbenzene sodium sulfonate – 

Alkylate 215 Lot CC 6772S – Acute toxicity screen. Project No. Y-72-274. 

Unpublished report. 

 Reliability: 2 Valid with restrictions 

 (j) 

 Species/strain: New Zealand white male and female rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [X]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Highly corrosive (causes severe burns) [ ]; 

 Corrosive (causes burns) [ ]; Irritating [X]; Not irritating [ ]

 Method: The clipped, intact and abraded skin of three New Zealand white male and 

female rabbits was applied with 0.5 g of finely ground sample moistened 

with water under a one inch by one inch square patch, two single layers 

thick. The patches were positioned in place with adhesive tape. The trunk of 

each animal was wrapped with plastic strips to avoid contamination and 

retard evaporation for the 24 hour exposure period. Observations were made 

over a period of seven days for irritation. The data was scored according to 

the method of Draize, Woodard and Calvery (Journal of Pharm. and Exp. 

Therapeutics, Volume 82, December 1944). 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-222L); average alkyl 

chain length = C11.5

 Remarks: Moderate to severe erythema and edema were present after 24 hours. These 

symptoms persisted through 120 hours. The average maximum score was 

7.0 out of a possible 8 at 24 hours. The compound was classed as a severe 

skin irritant. The sample had a defatting effect on the skin causing the skin to 

slough off in ten to fourteen days. There was no injury in depth. 

 Reference: Monsanto Company. 1972b. Linear alkylbenzene sodium sulfonate – 

Alkylate 222L Lot CC 6773S – Acute toxicity screen. Project No. Y-72-275. 

Unpublished report. 

 Reliability: 2 Valid with restrictions 

5.2.2 EYE IRRITATION/CORROSION

 (a) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ]
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 Method: OECD Guideline 405. Nine rabbits received a 0.1 mL aliquot of P-500 N-Na 

placed into the lower everted lid of one eye per animal. For three rabbits the 

eyelids were then gently held together for one second before releasing. For 

three other rabbits the eyes were irrigated with water for 5 minutes following 

a 4-second exposure. For the remaining three rabbits the eyes were irrigated 

for 5 minutes following a 30-second exposure. Eyes were examined after 1 

hour and 1, 2, 3, 4, 7, 14 and 21 days after exposure. Grading was performed 

using the standard scoring system. 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Alkylbenzene sulfonate, sodium salt (designated as P-500 N-Na). Activity 

47%. Average alkyl chain length = C11.2. Clear yellow liquid. 

 Remarks: The following results were noted: 

 1) Three animals without any rinsing: averaged irritation scores (24, 48, 72 

hours) for each animal: cornea 2.3, 1.7, 2; iris: 1.3, 0, 0; conjunctivae 

redness: 3, 1.7, 2; conjunctivae chemosis: 3, 2, 2. In the first animal the 

effects were persistent at day 14. 

 2) Three animals with rinsing for five minutes following a 30 second 

exposure: averaged scores: cornea 0.7, 1, 1.3; iris: 0, 0.7, 0.3; conjunctivae 

redness: 1.7, 2, 1.3; conjunctivae chemosis: 2, 1.3, 2. The eyes were normal 

7 or 14 days after instillation. 

3) Three animals with rinsing for five minutes following a 4 second 

exposure: averaged scores: cornea 0.7, 2.3, 0.7; iris: 0, 0, 0; conjunctivae 

redness: 1.7, 1.7, 1; conjunctivae chemosis: 1.3, 2, 1. The eyes were normal 

7 days after instillation. 

Findings lead to a definition of irritating for LAS at 47% applied without 

rinsing, irritating (even if with lower effects, mainly as cornea opacity and 

conjunctivae redness) with rinsing after 30 second of exposure, and not 

irritating with rinsing after 4 second of exposure. 

Overall, instillation of P-500 N-Na into the eyes of rabbits elicited positive 

responses in all animals. Irrigation of the eyes only slightly reduced the 

irritation potential. 

 Reference: Liggett, M.P. and Parcell, B.I. 1986b. Irritant effects on the rabbit eye of P500 N-Na. Huntingdon Research Ctr Report No. 86570D/PEQ 10/SE. 

Reliability: 1 Valid without restriction 

 (b) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ]

 Method: OECD Guideline 405. Six rabbits were exposed to 0.1 ml of 50% LAS, 

which was placed into the conjunctival sac of one eye per animal. The 

eyelids were gently held together for one second and then released. No 

irrigation step was performed The eyes were examined at 1, 24, 48 and 72 

hours and at 7 days and scored for irritation using the standard system. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (made from Sirene LAB); activity 50%; average alkyl chain length = 

C11.6

 Remarks: Average irritation scores were 1.3, 1.0, 2.6, and 2.7 for the cornea, iris, 

conjunctival redness, and conjunctival chemosis, respectively. Effects were 

persistent to Day 6. This classifies LAS at 50% as irritating. 

 Reference: Biolab SGS. 1989d. Acute eye irritation. Report No. 00428/13. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Species/strain: rabbit 
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 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: OECD Guide-line 405 "Acute Eye Irritation/Corrosion" 1981 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; activity: 50%. 

 Remarks: The mean irritation index was 26.5 out of 110. Individual scores: 

 1.0; iris: 0; conjunctivae chemosis: 1.11, conjunctivae redness: 2.39 

 Reference: Murmann, P. 1983b. Prufung der akuten Augen-und Schleimhautreiz 

Wirkung von Marlon A 350. Huels Report No. 0172. 

 Reliability: 2 Valid with restrictions 

 (d) 

 Species/strain: rabbit 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: OECD Guide-line 405 "Acute Eye Irritation/Corrosion" 1984 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: LAS 

 Remarks: Possibility of persistent effects on the eye. 

 Reference: Kaestner, W., Henkel KGaA, unpublished data, Report No. 870553 (1987). 

 Reliability: 4 Not assignable 

 (e) 

 Species/strain: rabbit 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: 0.1 mL solutions of LAS at 5 different concentrations ranging from 0.01 to 

1.0 % were instilled in the eyes of rabbits (13 per group). The rabbits were 

observed for 24 hours after LAS application. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, (CAS #68411-30-3). Molecular weight 346.5; average alkyl 

chain length = C11.9

 Remarks: Information as cited in IPCS document. The 0.01 % group showed no 

abnormalities, but the 0.05 % group showed slight congestion. The groups of 

0.5 % and higher concentrations showed marked reactions such as severe 

congestion and oedema, increased secretion, turbidity of the cornea, and 

disappearance of corneal reflex. 

 Reference: Oba, K., Mori, A. and Tomiyama, S. 1968. Biochemical studies of n-alphaolefin sulfonates (II) Acute toxicity, skin and eye irritation, and some other 

physical properties. Journ. Jap. Oil Chem. Soc. 17:628-634. (In Japanese) 

cited in: IPCS (1996); Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (f) 

 Species/strain: rabbit 
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 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [X]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: LAS solutions at 6 different concentrations ranging from 0.01% to 5.0% were 

instilled in the eyes of rabbits (3 per group). The rabbits were observed for 

168 hours after LAS application. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (chain length distribution C10-14; 80.9% of C11-13) (CAS #69669-44-9); 

average alkyl chain length (based on LAS SIDS Consortium Survey, 2000) = 

C11.7

 Remarks: Information as cited in IPCS document. The 0.01% group showed no 

reaction. Within 2 hours, the 0.05% group showed slight congestion and the 

0.1% group showed considerable congestion or oedema, which disappeared 

at 24 hours. In the group of 0.5% and higher, marked reactions such as 

severe congestion an oedema, increased secretion, turbidity of the cornea, 

and disappearance of the corneal reflex were observed for 24 hours. The 

effects disappeared completely at 120 hours. 

 Reference: Iimori, M., Ogata, T. and Kudo, K. 1972. Eye irritation testing of surface 

active agents in experimental animals. Jour. Jap. Oil Chem. Soc. 22:807-813 

(in Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: 

Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, 

Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (g) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [ ]; 

 Not irritating [X]

 Method: OECD Guideline 405. Six rabbits were exposed to 0.1 ml of 1% LAS, which 

was placed into the conjunctival sac of one eye per animal. The eyelids were 

gently held together for one second and then released. No irrigation step was 

performed The eyes were examined at 1, 24, 48 and 72 hours and at 7 days 

and scored for irritation using the standard system. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (made from Sirene LAB); activity 1%; average alkyl chain length = 

C11.6

 Remarks: Average irritation scores were 0, 0, 0.1, and 0.1 for the cornea, iris, 

conjunctival redness, and conjunctival chemosis, respectively. This 

classifies LAS at 1% as not irritating. 

 Reference: Biolab SGS. 1984. Acute eye irritation. Report No. T3R/27. 

 Reliability: 2 Valid with restrictions 

(h) 

 Species/strain: New Zealand albino rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [X]; Slightly irritating [ ]; 

 Not irritating [ ]

 Methods: OECD Guideline 405. Six rabbits were exposed to 0.1 ml of 5% LAS, which 

was placed into the conjunctival sac of one eye per animal. The eyelids were 

gently held together for one second and then released. No irrigation step was 

performed The eyes were examined at 1, 24, 48 and 72 hours and at 7 days 

and scored for irritation using the standard system. 
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 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (made from Sirene LAB); activity 5%; average alkyl chain length = 

C11.6

 Remarks: Average irritation scores were 0, 0, 1.83, and 1.16 for the cornea, iris, 

conjunctival redness, and conjunctival chemosis, respectively. This 

classifies LAS at 5% as moderately irritating. 

 Reference: Biolab SGS. 1988. Acute eye irritation. Report No. T343. 

 Reliability: 2 Valid with restrictions 

 (i) 

 Species/strain: albino male and female rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [X]; Slightly irritating [ ]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: A total of 100 mg of finely ground sample was administered in the 

conjunctival sac of the right eye of each of six albino male and female 

rabbits. Observations for inflammation were made over seven days. The 

treated eyes were washed with sodium chloride solution USP after the 24 

hour reading. The left eye served as a control. The data was scored 

according to the method of Draize, et al. Tests were conducted in accordance 

with the Federal Hazardous Substance Act. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-225) C9 1%, C10 7%, C11

25%, C12 48%, C13 19%, C14 1%; average alkyl chain length = C11.9

 Remarks: The compound is classified as an eye irritant under the grading system as 

outlined in the Federal Hazardous Substances Act. Slight to moderate 

erythema was present after 10 minutes and persisted through 72 hours. 

Edema was present after 1 hour and persisted through 24 hours. The average 

maximum irritation score was 19.3 out of a possible 110. 

 Reference: Monsanto Company. 1971. Linear alkylbenzene sodium sulfonate – 

Alkylate 225 Lot CC 6450 – Acute toxicity screen. Project No. Y-71-119. 

Unpublished report. 

 Reliability: 2 Valid with restrictions 

 (j) 

 Species/strain: albino male and female rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [X]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: A total of 100 mg of finely ground sample was administered in the 

conjunctival sac of the right eye of each of three albino male and female 

rabbits. Observations for inflammation were made over seven days. The 

treated eyes were washed with isotonic saline solution after the 24 hour 

reading. The left eye served as a control. The data was scored according to 

the method of Draize, et al. Tests were conducted in accordance with the 

Federal Hazardous Substance Act. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-215) C9 1%, C10 16%, C11

43%, C12 40%, C13 1%, C14 <1%; average alkyl chain length = C11.35

 Remarks: Slight erythema and a copious discharge were present 10 minutes after 

application. A slight erythema persisted for 72 hours after which the eyes 

returned to normal. The average maximum score was 10 out of a possible 

110 after 24 hours. This compound is classified as a slight eye irritant. 
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 Reference: Monsanto Company. 1972a. Linear alkylbenzene sodium sulfonate – 

Alkylate 215 Lot CC 6772S – Acute toxicity screen. Project No. Y-72-274. 

Unpublished report. 

 Reliability: 2 Valid with restrictions 

 (k) 

 Species/strain: albino male and female rabbits 

 Results: Highly corrosive [ ]; Corrosive [ ]; Highly irritating [ ]; 

 Irritating [ ]; Moderate irritating [ ]; Slightly irritating [X]; 

 Not irritating [ ] 

 Classification: Irritating [X]; Not irritating [ ]; Risk of serious damage to eyes [ ]

 Method: A total of 100 mg of finely ground sample was administered in the 

conjunctival sac of the right eye of each of three albino male and female 

rabbits. Observations for inflammation were made over seven days. The 

treated eyes were washed with isotonic saline solution after the 24 hour 

reading. The left eye served as a control. The data was scored according to 

the method of Draize, et al. Tests were conducted in accordance with the 

Federal Hazardous Substance Act. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium sulfonate of linear alkylbenzene (Alkylate-222L; average alkyl chain 

length = C11.5) 

 Remarks: Moderate erythema and slight edema and a copious discharge were present 

10 minutes after application. A slight erythema persisted for 72 hours after 

which the eyes returned to normal. The average maximum score was 18 out 

of a possible 110 after 24 hours. This compound is classified as a mild eye 

irritant. 

 Reference: Monsanto Company. 1972b. Linear alkylbenzene sodium sulfonate – 

Alkylate 222L Lot CC 6773S – Acute toxicity screen. Project No. Y-72-

275. Unpublished report. 

 Reliability: 2 Valid with restrictions 

5.3 SKIN SENSITIZATION 

(a) 

Type: Sensitisation test 

Species/strain: Guinea pig (males & females, albino) 

Results: Sensitising [ ]; Not sensitising [X]; Ambiguous [ ] 

Classification: Sensitising [ ]; Not sensitising [X]

Method: Buehler Test; OECD Guideline 406 "Skin Sensitization" 1981; Directive 

84/449, EEC B.6. "Acute Toxicity - Skin Sensitization". 

GLP: Yes [X] No [ ] ? [ ] 

Test Substance: LAS; activity: 6.7%; average alkyl chain length = C11.6

Remarks: The purpose of this study was to assess the allergenic potential of LAS when 

administered to the skin. 10 animals (5M/5F) remained untreated and were 

used as controls to be treated at first challenge. 10 animals (5M/5F) 

remained untreated and were used as additional controls to be treated at 

second challenge; 20 animals (10M/10F) were treated with LAS. Induction 

concentration was 1.0% in water; first and second challenge concentrations 

were 0.8% in water. 0/20 animals responded in the treated group; 0/10 

animals responded in the control group. 

Reference: European Commission. 2000o. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition, citing The Procter & Gamble 

Company, unpublished data, Reports No. RCC-2315547. 

Reliability: 4 Not assignable 
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(b) 

 Type: Guinea pig maximisation test 

 Species/strain: guinea pig, females 

 Results: Sensitising [ ]; Not sensitising [X]; Ambiguous [ ]

 Classification: Sensitising [ ]; Not sensitising [X]

 Method: OECD Guide-line 406 "Skin Sensitisation" 1981 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Marlon A 350 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; activity: 50%. 

 Remarks: 0.1% intracutaneous and 3% epidermal doses. No sensitizing effects were 

observed. 

 Reference: Murmann, P. 1988. Prufung auf hautsensibilisierende Wirkung am 

Meerschweinchen von Marlon A 350. Huels Report No. 1387. 

 Reliability: 2 Valid with restrictions

 (c) 

 Type: Maximization test 

 Species/strain: Guinea pig, Hartley 

Results: Sensitising [ ]; Not sensitising [X]; Ambiguous [ ]

Classification: Sensitising [ ]; Not sensitising [X]

Method: OECD Guideline 406, 1981; Directive 179/831 Annex, Part B. 

GLP: Yes [X] No [ ] ? [ ]

Test substance: LAS, activity: 50%; average alkyl chain length = C11.6

Remarks: Solutions of LAS were applied intracutaneously and epicutaneously to 10 

male and 10 female animals. Induction concentration was 25% in water; the 

challenge concentration was 12.5%. No positive responses were observed. 

Reference: RBM. 1985. Test di sensibilizzazione cutanea nella cavia. RBM Exp. No. 

2076. 

Reliability: 1 Valid without restriction 

 

5.4 REPEATED DOSE TOXICITY

 (a) 

 Species/strain: Rat (FDRL) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: Oral feed 

 Exposure period: 12 weeks 

 Dose: 50 or 250 mg/kg bw d 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: 50 mg/kg bw d 

 LOAEL: 250 mg/kg bw d 

 Results: No behavioural abnormalities were noted during the test period. Growth 

responses were equal in all groups. There were no differences in food intake 

or in efficiency of food utilization. The clinical data showed no abnormal 

variations in any of the dose groups. The relative organ weights and the 

histopathological evaluation did not show significant differences among the 

dose groups except a liver weight increase in female animals of the high dose 

group. 

 Method: Based on Fitzhugh and Schouboe (1959) Subacute toxicity in: Assoc. Food 

Drug Offices of the U.S., Austin, Texas, p. 26-35. Weanling rats were 

distributed into 5 groups of 15 male and 15 female animals per dose group. 

All rats were given standard diet daily. Doses were 0, 50 and 250 mg/kg bw 

d in the diet. Daily observations of behavior and signs of toxicity were made. 

Food consumption and blood and urine chemistries were also measured 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 271

periodically. Organ weights and gross pathological findings were measured 

at the end of the study in the liver, kidneys, spleen, heart, adrenals, pituitary, 

and cecum. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, sodium salt, activity: 39.5%; average molecular weight 346; 

average alkyl chain length = 11.9 

 Reference: Oser, B.L. and Morgareidge, K. 1965. Toxicological studies with branched 

and linear alkyl benzene sulfonates in rats. Toxicol. Appl. Pharmacol. 7:819-

825. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Species/strain: rat (Sprague-Dawley) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 90 days 

 Frequency of treatment: Ad libitum

 Dose: 0.02/0.1/0.5% (corresponding to 8.8, 44 and 220 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: 0.5% (220 mg/kg bw d) 

 Results: No adverse effects were found upon the following parameters: growth, food 

efficiency, survival, haematologic values, and urinary analytical values. In 

addition, no treatment-related adverse effects were observed in absolute and 

relative organ weights, nor were gross histopathological changes observed in 

any of the organs examined. 

 Method: Groups of 10 male and 10 female weanling rats were fed levels of 0.02, 0.1 

or 0.5% LAS in a commercial chow for 90 days. Body weights, food 

consumption, mortality, and several blood parameters were measured 

periodically during the study and at termination. Autopsy and microscopic 

examination of the organs was performed at test termination. Organ weights 

and gross pathological findings were recorded for the liver, kidneys, spleen, 

gonads, heart, and brain. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salt (CAS #69669-44-9), activity: 87.9%; C10 1.8%, C11

43.2%, C12 32.2%, C13 16.0%, C14 5.3%, C15 1.5%; average alkyl chain 

length = C11.8; mean molecular weight 346. 

 Remarks: Two male rats at the 0.2% level died in the early stages of the study. These 

deaths were attributed to respiratory illness and were not considered to be 

treatment related. 

 Reference: Kay, J.H., Kohn, F.E. and Calandra, J.C. 1965. Subacute oral toxicity of a 

biodegradable linear alkylbenzene sulfonate. Toxicol. Appl. Pharmacol. 

7:812-818. 

 Reliability: 2 Valid with restrictions 

(c) 

 Species/strain: Rat/Sprague-Dawley 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: gavage 

 Exposure period: one month 

 Frequency of treatment: daily 

 Dose: 125, 250, 500 mg/kg bw d. 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: 125 mg/kg bw d 

 LOAEL: 250 mg/kg bw d 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

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 Results: Diarrhea was observed in the 500 mg/kg group and soft stools were observed 

in the other 2 groups. Body weight gain was suppressed in all the male 

groups and in the female 500 mg/kg group. Haematological examinations 

revealed no abnormalities. Serum-biochemical examinations revealed 

several differences among the mid and high dose group compared to the 

control group. The weight of the spleen and the heart significantly decreased 

in the male high dose group. In the female high dose group, the weight of the 

liver increased while the weight of the heart and thymus decreased. 

Histological findings of the liver revealed no abnormalities. 

 GLP: Yes [ ] No [X] ? [ ]

 Remarks: Information as cited in IPCS document. 12 animals per dose group. 

 Test substance: C10-13 LAS, sodium salt (CAS #68411-30-3) 

 <C10 0.1%, C 10 10.1%, C 11 33.7%, C 12 31.0%, C 13 25.1%; average alkyl 

chain length = C11.7; activity: 99.5% 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Ito, R., Kawamura, H., Chang, H.S., Kudo, K., Kajiwara, S., Toida, S., 

Seki, Y., Hashimoto, M. and Fukushima, A. 1978. J. Med. Soc. Toho, 

Japan, 25:850-875 (in Japanese). cited in IPCS. 1996. Environmental 

Health Criteria 169: Linear Alkylbenzene Sulfonates and Related 

Compounds. World Health Organization, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (d) 

 Species/strain: Rat (Wistar) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 9 months 

 Frequency of treatment: Daily in feed 

 Dose: 0.6% and 1.8% (260 and 780 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]

 LOAEL: = 0.6% (260 mg/kg bw d) 

 Results: In the 1.8% dose group, the body weight gain was suppressed and 

haematological and serum-biochemical adverse effects were observed in both 

treatment groups of both sexes. The weight of the cecum of the male rats and 

the weight of the liver and cecum of the females in the high dose groups were 

significantly increased. Enzymatic examinations of the liver and kidneys 

revealed changes in different enzyme activities in the 1.8% groups. The 

intake of LAS was 230 mg/kg bw d in the male 0.6% group and 290 mg/kg 

bw d in the female 0.6% group. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salt (CAS #69669-44-9) C10 10.6%, C11 34.1%, C12

27.7%, C13 19.0%, C14 8.7%; average alkyl chain length = C11.8; mean 

molecular weight: 345.8. 

 Remarks: Information as cited in IPCS document. 8 rats were used per dose group. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Yoneyama, M., Mabuchi, Y., Ikawa, M., Kobayaski, H. and Ichikawa, H. 

1976. Subacute toxicity of linear alkyl benzene sulfonate. Ann. Rep. Tokyo 

Metr. Res. Lab. P.H. 27(2): 105-112 (in Japanese); cited in: IPCS (1996); 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) 

and Related Compounds. WHO, Geneva, Switzerland. 
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 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (e) 

 Species/strain: Rat (Wistar) 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: oral feed 

 Exposure period: 2, 4, 12 weeks 

 Frequency of treatment: Daily in feed 

 Dose: 1.5% (750 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]

 LOAEL: 1.5% (750 mg/kg bw d) 

 Results: LAS suppressed body weight gain, and the relative liver weight was 

increased from 2 weeks of LAS administration. Serum biochemical 

examinations revealed significant increases in ALP and GTP at each 

observation period and significant decreases in cholesterol and protein in 4 

weeks. Enzymatic examinations of the liver revealed decreases in G6Pase 

and G6PDH and an increase in isocitrate dehydrogenase (IDH) at each 

observation period. Enzymatic examinations of the renal cortex revealed 

decreases in G6Pase and 5'-nucleotidase at each observation period, an 

increase in LDH at 12 weeks, and an increase in IDH at 2 and 4 weeks. 

Enzymatic examinations in the renal medulla revealed a decrease in NA,KATPase, an increase in LDH at 12 weeks, a decrease in IDH at 2 weeks, and 

an increase in IDH at 12 weeks. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (unspecified) 

 Remarks: Information as cited in IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Ikawa, M., Yoneyama, M., Nakao, T. and Hiraga, K. 1978. Uptake of 

organic acid and organic base by renal cortical slices of rats treated with LAS 

and ABS. Ann. Rep. Tokyo Metr. Res. Lab. P.H. 29:51-54 (in Japanese); 

cited in: IPCS (1996); Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 

 (f) 

 Species/strain: Rat (Wistar) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 6 months 

 Frequency of treatment: Daily in feed 

 Dose: 0.07, 0.2, 0.6, 1.8% (40, 115, 340, 1030 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: = 40 mg/kg bw d 

 LOEL: = 115 mg/kg bw d 

 Results: The 1.8% group showed diarrhoea, markedly suppressed growth, increased 

weight of the cecum, and remarkable degeneration of the renal tubes. The 

0.6% group showed slightly suppressed growth, increased weight of the 

cecum, increased activity of serum alkaline phosphatase (ALP), a decrease in 
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serum protein and degeneration of the renal tubes. The 0.2% group showed 

increased weight of the cecum and slight degeneration of the renal tubes, the 

0.07% group showed no adverse effects related to the administration of LAS. 

The intake of LAS in the 0.07% group was about 40 mg/kg bw d. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salt (CAS #69669-44-9). C10 10.6%, C11 34.1%, C12

27.7%, C13 19.0%, C14 8.7%; average alkyl chain length = C11.8; mean 

molecular weight: 345.8. 

 Remarks: Information as cited in IPCS document. This is a key study for repeated dose 

toxicity because it represents the lowest LOAEL (see SIAR Table 6). 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Yoneyama, M. Fujii, T., Ikawa, M., Shiba, H., Sakamoto, Y., Yano, N., 

Kobayashi, H., Ichikawa, H. and Hiraga, K. 1972. Studies on the toxicity of 

synthetic detergents. (II) Subacute toxicity of linear and branched alkyl 

benzene sulfonates in rats. Ann. Rep. Tokyo Metrap. Res. Lab. Public 

Health. 24:409-440. (In Japanese). cited in IPCS (1996); Environmental 

Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) and Related 

Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (g) 

 Species/strain: Rat 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: gavage 

 Exposure period: 10 weeks 

 Doses: 50, 100 or 250 mg/kg bw d 

 Control: Yes [X]; No [ ]; No data [ ];Concurrent no treatment [X]; 

 Concurrent vehicle [ ]; Historical [ ]

 LOEL: 50 mg/kg bw d 

 Results: Histopathology was evaluated in the females only. At the highest dose level, 

the kidneys showed mild degeneration and desquamation of the tubular 

epithelium and there was a moderate degree of fatty change in the liver as 

well as proteinaceous degeneration. Sections of the intestine did not exhibit 

any significant histologic variation. Adenosine triphosphatase activity was 

inhibited with increasing dose in both sexes while alkaline phosphatase and 

acid phosphatase activities were increased with increasing dose. The activity 

of lactate dehydrogenase was significantly inhibited at all dose levels in 

females but was not measured in males. SGOT and SGPT were significantly 

decreased in females at 100 and 250 mg/kg/day and SGPT was inhibited in 

males at 250 mg/kg/day. 

 Method: Twenty four male (50+/-5g) and 36 female (40+/-5g) rats were given daily 

oral (cannula) doses of LAS detergent solution (0, 50, 100 and 250 mg/kg) 

by gavage for 10 weeks. Animals were maintained on standard pellet diets 

and drinking water ad libitum. After 10 weeks, animals were fasted for 24 

hours and sacrificed. Liver, kidney, heart, and intestine were removed 

immediately, weighed, and parts sectioned for histological examinational. 

The remaining parts of the liver and kidney homogenized in ice cold 0.25 M 

sucrose solution using Potter-Elvehjem type homogenizer and 10% w/v 

homogenates were prepared for histopathology and enzyme analysis. The 

activities of adenosine triphoshatase (ATPase), acid phosphatase (ACP), 

alkaline phosphatase (ALP), glutamic oxaloacetic transaminase (GOT), and 

glutamic pyruvic transaminase (GPT) were determined in the homogenates. 

 GLP: Yes [ ] No [X] ? [ ] 
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 Remarks: All of the effects observed are related to energy metabolism, so given the 

lack of morphological and structural changes, the reduced food intake and 

body weight gain may have compromised energy dynamics and affected the 

enzyme levels. The reliability and use of this study for risk assessment 

purposes is limited and the 50 mg/kg/day level should be considered a LOEL 

rather than a LOAEL. 

 Test Substance: Commercial LAS synthetic detergent solution 

 Reference: 1) Gupta, B.N., Mathur, A.K., Agarwal, C., and Singh, A. 1986. Effect of 

synthetic detergent on certain enzymes in liver and kidney in male rats. 

Arogya-J. Health Sci. 12:50-54. 

 2) Mathur, A.K., Gupta, B.N., Singh, A., and Shanker, R. 1986. 

Toxicological evaluation of a synthetic detergent after repeated oral ingestion 

in rats. Biol. Mem. 12:187-191. 

 Reliability: 2 Valid with restrictions 

 

 (h) 

 Species/strain: Rat (Wistar) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: drinking water 

 Exposure period: 9 months 

 Frequency of treatment: Daily in drinking water. 

 Dose: 0.07, 0.2%, 0.6% (85, 145, 430 mg/kg bw d; average of male and female) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: 0.07% (85 mg/kg bw d) 

 LOAEL: 0.2% (145 mg/kg bw d) 

 Results: Body weight gain was suppressed in the male 0.6% group. Hematological 

examination revealed no significant change in any of the experimental 

groups, but a dose-related decrease in cholesterol level was seen in males. 

Significant decreases in the activities of glutamate-oxalate transaminase and 

lactate dehydrogenase were seen in males at 0.2% and a dose-related increase 

in the activity of glutamate-oxalate transaminase in females. A significant 

decrease in renal Na,K-ATPase was seen in the group given 0.2%. No organ 

weight changes were observed. The intake of LAS was 50 mg/kg bw d in the 

male 0.07% group and 120 mg/kg bw d in the female group. The values for 

the 0.2% group were 120 and 170 mg/kg bw d for males and females, 

respectively. 

 Method: Groups of 8-9 male and 8-9 female rats were given LAS for 9 months. 

 GLP: Yes [ ] No [X] ? [ ]

 Remarks: Information as cited in IPCS document. This is a key study for repeated dose 

toxicity because it represents the highest NOAEL below the lowest LOAEL 

(see SIAR Table 6). 

 Test substance: C10-14 LAS (CAS #69669-44-9); average alkyl chain length (based on LAS 

SIDS Consortium Survey, 2000) = C11.7

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Yoneyama, M., Mabuchi, Y., Ikawa, M., Kobayashi, H. and Ichikawa, H. 

1976. Subacute toxicity of linear alkylbenzene sulfonate. Ann. Rep. Tokyo 

Metr. Res. Lab. Public Health 27:105-112 (in Japanese); cited in: IPCS 

(1996); Environmental Heath Criteria 169: Linear Alkylbenzene Sulfonates 

(LAS) and Related Compounds. WHO Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 

 (i) 
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 Species/strain: mouse (DDY) 

 Sex: Female [ ]; Male [ ]; Male/Female [ ]; No data [X]

 Administration: drinking water 

 Exposure period: 6 months 

 Frequency of treatment: Daily 

 Observation period: 2 months post exposure 

 Dose: 100 ppm in the drinking water (20 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ] 

 Results: Atrophy of the golgi apparatus, degeneration of the mitochondria, and 

increased appearance of lysosomes were observed. The severity of these 

adverse effects were dependent on the length of the administration. After six 

months, some cells showed degenerative cytoplasm and indications of cell 

necrosis. Effects on the rough endoplasmatic reticulum were observed. 

Some animals still showed cellular effects after the two months post 

administration period while other animals showed full recovery. Given the 

unknown significance of the effects for the health of the animals and the 

reversibility of the effects, as well as the consistent lack of adverse effects in 

other studies at similar or higher doses, the dose tested in this study is 

considered a LOEL rather than a LOAEL. 

 Method: LAS was administered up to 6 months. The animals were sacrificed at 1, 2, 

3, and 6 months. Some animals were observed an additional 2 months 

without test substance administration. Liver slices were investigated using 

electron microscopy. 

 GLP: Yes [ ] No [X] ? [ ] 

Remarks: The reliability and usefulness of this study for risk assessment purposes is 

limited. The study employed only a single dose (i.e., no dose response 

information). In addition, there is the likelihood of dehydration of the 

animals. Because of these study deficiencies, it was determined that it is 

inappropriate to derive a LOAEL from this study. 

 Test substance: LAS (unspecified) 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Watari, N., Torizawa, K., Kanai, M. and Suzuki, Y. 1977. Ultrastructural 

observations of the protective effect of glycyrrhizin for mouse liver injury 

caused by oral administration of detergent ingredient (LAS) J. Clin. Electron. 

Microscopy 10:121-139 (in Japanese) cited in IPCS. 1996. Environmental 

Health Criteria 169: Linear Alkylbenzene Sulfonates and Related 

Compounds. World Health Organization, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. While the study was evaluated by IPCS prior 

to inclusion in their criteria document, the deficiencies noted above make 

its usefulness in risk assessment questionable. 

 

 (j) 

 Species/strain: mouse (ICR) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: Oral feed or water 

 Exposure period: 9 months 

 Frequency of treatment: Daily 

 Dose: Diet: 0.6 and 1.8% (corresponding to 500 and 1000 mg/kg bw d). 

 Diet: Drinking water: 0.07, 0.2, and 0.6% (100, 250, and 600 mg/kg bw d for 

males and 100, 250, and 900 mg/kg bw d for females) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: 250 mg/kg bw d in drinking water 
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UNEP PUBLICATIONS 277

 LOAEL: 500 mg/kg bw d in diet 

 Results: In the mice given 0.6% in their diet, body weight gain was not suppressed, 

but the weight of the liver increased in male and female mice. Enzymatic 

examinations revealed significant decreases in LDH of the liver and in acid 

phosphatase of the kidneys in the male mice. For mice given LAS in 

drinking water, body weight was depressed at the highest dose for males and 

females. This dose also elicited an increase in liver weight in females and 

significant decreases in renal Na and K-ATPase. 

 Method: Groups of 8 or 9 mice were given diets containing LAS at concentrations of 

0.6 and 1.8% or drinking water containing LAS at concentrations of 0.07, 

0.2, and 0.6% for 9 months. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Yoneyama, M., Mabuchi, Y., Ikawa, M., Kobayashi, H. and Ichikawa, H. 

1976. Subacute toxicity of linear alkylbenzene sulfonate. Ann. Rep. Tokyo 

Metr. Res. Lab. P.H. 27(2):105-112 (in Japanese); cited in: IPCS (1996); 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) 

and Related Compounds. WHO, Geneva, Switzerland. 

 3) HERA. 2002. HERA-LAS Human and Environmental Risk Assessment: 

Linear Alkylbenzene Sulphonates, LAS. CAS No. 68411-30-3, Draft #6, 

May 2002. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (k) 

 Species/strain: Rat: Charles River 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 2 years 

 Frequency of treatment:continuous in feed 

 Doses: 0.02, 0.1, 0.5% (10, 50, 250 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ X]; Concurrent vehicle [ ]; Historical [X]

 Results: Gross examination of all animals for pathology did not reveal any 

abnormalities. No consistent dietary induced changes that could be 

considered a toxic response were observed. Animals that showed significant 

loss of weight, development of tumors, or other evidence of abnormalities 

were sacrificed and tissues examined. The incidence of tumors and the 

common incidental diseases were similar in all dieting groups. No treatmentrelated adverse histological effects were observed in any of the tissue sections 

examined. 

 Method: Four groups of Charles River weanling rats, divided by sex, were given 0.5, 

0.1, and 0.02% LAS in their food for 2 years. Following completion of those 

studies, five male and five female rats from each of the parental groups (F1b

and F2b) and all survivors were selected for necropsy. Livers and kidneys 

were removed and weighed. Body weight and organ to body weight ratios 

were recorded, and routine hematology and histology were performed. 

Sections for histological examination were taken from the liver, kidney, 

thyroid, trachea, esophagus, lung, heart, spleen, pancreas, adrenals, stomach, 

small intestine, urinary bladder, gonads and mesenteric lymph nodes. 

Weanling animals for the F3a generation were similarly treated. 

 GLP: Yes [ ] No [X] ? [ ]
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UNEP PUBLICATIONS 278

 Test substance: C10-14 LAS, sodium salt; activity: 98.1% on an anhydrous basis (41.9% 

active) 

 Reference: Buehler, E.V., Newmann, E.A., and King, W.R. 1971. Two year feeding 

and reproduction study in rats with linear alkylbenzene sulfonate (LAS). 

Toxicol. Appl. Pharmacol. 18:83-91. 

 Reliability: 2 Valid with restrictions 

 (l) 

 Species/strain: Rat/Wistar 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: Drinking water 

 Exposure period: 2 years 

 Frequency of treatment: Daily 

 Doses: 0.01%, 0.05%, 0.1% (20,100, 200 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 Results: There were no changes due to the administration of LAS in regard to growth, 

mortality, the weight of major organs, or histopathological findings. The 

intake of LAS was about 200 mg/kg bw d in the 0.1% group. 

 Method: Groups of 20 male Wistar rats were given LAS in drinking water daily for 2 

years. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS, activity: 34.55% 

 Remarks: Information as cited in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Tiba, S. 1972. Studies on the acute and chronic toxicity of linear 

alkylbenzene sulfonate. J. Food Hyg. Soc. Jpn. 16:66-71 (in Japanese); cited 

in: IPCS (1996); Environmental Health Criteria 169: Linear Alkylbenzene 

Sulfonates (LAS) and Related Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 

 (m) 

 Species/strain: Rhesus monkey (Macaca mulatta) 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: Simultaneous oral and subcutaneous 

 Exposure period: 28 days 

 Frequency of treatment:daily 

 Dose: 30, 150, 300 mg/kg/day oral via gavage given simultaneously with 0.1, 0.5, 

1.0 mg/kg/day subcutaneous administration 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL: 150 mg/kg/day (oral) with 0.5 mg/kg/day (sc) 

 Results: At 300 (oral) and 1.0 (sc) mg/kg/day, the monkeys vomited frequently and 

usually within 3 hours of administration. An increased frequency of loose or 

liquid faeces was recorded for animals receiving 150 (oral) and 0.5 (sc) 

mg/kg. These effects are probably related to the inherent irritative effects of 

LAS rather than its systemic toxicity. Fibrosis of the injection sites was 

found among all the test group, the incidence and severity being dose related. 

Ophthalmoscopy, laboratory examination of blood and urine, organ weight 

analysis and histopathological investigation did not detect any further 

treatment-related responses. 

 Method: Three male and 3 female monkeys were given simultaneous oral and 

subcutaneous administration doses daily for 28 days. Animals were observed 
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UNEP PUBLICATIONS 279

for physical and behavioral signs of toxicity. Analysis of blood, 

biochemistry and urine were conducted. Monkeys were held in individual 

wall-mounted cages at a room temperature of 22+

/-1oC and normal daylight. 

Food consisted of 300 g dry diet and bread daily, and fresh fruit on alternate 

days. Tap water for drinking was freely available. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-13 LAS, activity: 20.5% 

 Remarks: The SDA/NOTOX report sets a systemic NOAEL of 30 mg/kg/day (oral) 

with 0.1 mg/kg/day (sc). However, based on the information provided in the 

article and reiterated above, the actual systemic NOAEL is considered to be 

150 mg/kg/day (oral) with 0.5 mg/kg/day (sc). According to the authors, the 

three combined doses correspond to 100, 500 and 1000 times the estimated 

maximum human daily intake. 

 Reference: Heywood, R., James, R.W., and Sortwell, R.J. 1978. Toxicology studies of 

linear alkylbenzene sulphonate (LAS) in rhesus monkeys. I. Simultaneous 

oral and subcutaneous administration for 28 days. Toxicology 11:245-250. 

 Reliability: 2 Valid with restrictions 

 

 (n) 

 Species/strain: Rat (Wistar) 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: Dermal 

 Exposure period: 15 days 

 Frequency of treatment: daily 

 Dose: 0.5 g applied 20 and 30% LAS solutions (about 286 and 427 mg/kg bw d) 

 Control group: Yes [ ]; No [ ]; No data [ ]; 

 Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]

 LOAEL: 20% (286 mg/kg bw d) (lowest dose tested) 

 Results: Body weight gain was suppressed in the 20% group and the body weight was 

decreased in the 30% group. An infiltrating, yellowish-reddish brown crust 

was observed 2-3 days in the 20% group, and at 1-2 days in the 30% group. 

At 4-6 days the crust was abraded and erosion occurred at the abraded site. 

Histological examinations of the application site revealed severe necrosis of 

the region from the epidermis cuticle to the upper layer of the dermis, severe 

infiltration of leukocytes in the necrotic site, diffuse inflammatory cell 

infiltration of all layers of the corium. No changes were observed in the 

tongue, but the oral mucosa revealed atrophy and slight degeneration of the 

epithelium. No systemic effects were observed. 

 Method: LAS was applied to the backs of the rats. On the 16th day of the experiment, 

skin at the application site and the tissues of the tongue and oral mucosa (to 

examine the effects of licking) of the rats that received 30% were examined 

histologically. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS, activity: 99.9% 

 Remarks: Information as cited in the IPCS document. Because of necrosis at the 

application site, it is not possible to know exactly how much LAS was 

absorbed. Effects were probably due to local effects, so the results are best 

described as a local LOAEL. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Sadai, M. and Mizuno, N. 1972. Effect of long term topical application of 

some anionic surfactants on the skin, oral mucous membrane, and tongue. 

Jpn Journal Dermatol. 82:207-221. (in Japanese); cited in: IPCS (1996); 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) 

and Related Compounds. WHO, Geneva, Switzerland. 
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 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

5.5 GENETIC TOXICITY IN VITRO

A. BACTERIAL TEST

 (a) 

 Type: Ames test 

 System of testing: Salmonella typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100 

 Concentration: 8 -5000 ug/plate 

 Metabolic activation: With [ ]; Without [ ]; With and Without [X]; No data [ ]

 Results: 

 Cytotoxicity conc: With metabolic activation: > 5000 μg/plate 

 Without metabolic activation: > 5000 μg/plate 

 Genotoxic effects: + ? - 

 With metabolic activation: [ ] [ ] [X]

 Without metabolic activation: [ ] [ ] [X]

 Method: Directive 84/449/EEC, B.14 Mutagenicity (Salmonella 

typhimurium - reverse mutation assay)" 1984 

 GLP: Yes [X] No [ ] ? [ ]

 Test substance: Marlon A 390 (CAS #68411-30-3) C10-13 LAS, average alkyl chain length = 

C11.6; activity 91.3% 

 Remarks: Negative and positive controls used. 

 Reference: Schoeberl, P. 1993a. Bestimmung der Mutagenitat von Marlon A 390 im 

Salmonella/Sauger-Mikrosomen-Mutagenitatstest nach Ames. Huels Final 

Report No. AM-93/12. 

 Reliability: 1 Valid without restriction 

 (b) 

 Type: Ames test 

 System of testing: Salmonella typhimurium TA 100, TA 98 

 Concentration: 10, 25, 50, 100 and 200 ug/plate 

 Metabolic activation: With [ ]; Without [ ]; With and Without [X]; No data [ ]

 Results: 

 Cytotoxicity conc: With metabolic activation: > 200 μg/plate 

 Without metabolic activation: > 200 μg/plate 

 Genotoxic effects: + ? - 

 With metabolic activation: [ ] [ ] [X]

 Without metabolic activation: [ ] [ ] [X]

 Method: Ames test 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salts (CAS#69669-44-9); average alkyl chain length 

(based on LAS SIDS Consortium Survey, 2000) = C11.7; activity: 22.2% 

 Remarks: Not mutagenic 

 Reference: Inoue, K., Sunakawa, T. and Takayama, S. 1980. Studies of in vitro cell 

transformation and mutagenicity by surfactants and other compounds. Fd. 

Cosmet. Toxicol. 18:289-296. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Type: Ames test 

 System of testing: Salmonella typhimurium TA 98, TA 100 

 Concentration: up to 500 ug/plate 
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 Metabolic activation: With [ ]; Without [ ]; With and Without [X]; No data [ ]

 Results: 

 Cytotoxicity conc: With metabolic activation: > 500 μg/plate 

 Without metabolic activation: > 500 μg/plate 

 Genotoxic effects: + ? - 

 With metabolic activation: [ ] [ ] [X]

 Without metabolic activation: [ ] [ ] [X]

 Method: Ames test 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salts (CAS #69669-44-9); average alkyl chain length 

(based on LAS SIDS Consortium Survey, 2000) = C11.7; activity: 20.5% 

 Remarks: Information as cited in IPCS documents. Not mutagenic 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

2) Sunakawa, T., Inoue, K. and Okamoto, K. 1981. Studies on the 

mutagenicity of surfactants, mutagenicity of surfactants following activation 

with various liver homogenates (S-9) and mutagenicity in the presence of 

norharman. Hyg. Chem. 27:204-211. (In Japanese); Cited in IPCS. 1996. 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates and 

Related Compounds. World Health Organization, Geneva, Switzerland. 

Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (d) 

 Type: Bacillus subtilis recombination assay 

 System of testing: H17 (rec+) and M45 (rec-) 

 Concentration: Up to 50 μg/plate 

 Metabolic activation: With [ ]; Without [ ]; With and Without [X]; No data [ ]

 Results: 

 Cytotoxicity conc: With metabolic activation: > 50 μg/plate 

 Without metabolic activation: > 50 μg/plate 

 Genotoxic effects: + ? - 

 With metabolic activation: [ ] [ ] [X]

 Without metabolic activation: [ ] [ ] [X]

 Method: Bacillus recombination assay 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salts (CAS #69669-44-9); average alkyl chain length 

(based on LAS SIDS Consortium Survey, 2000) = C11.7; activity: 99.5% 

 Remarks: Information as cited in IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Inoue, IK. and Sunakawa, T. 1979. Mutagenicity tests of surfactants. Jpn 

Fragrance J. 38:67-75 (in Japanese); cited in: IPCS (1996); Environmental 

Health Criteria 169: for Linear Alkylbenzene Sulfonates (LAS) and Related 

Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (e) 

 Type: Escherichia coli reverse mutation assay. 

 System of testing: WP23 uvr A 

 Concentration: Not specified 

 Metabolic activation: With [ ]; Without [ ]; With and Without [X]; No data [ ]

 Results: 
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 Cytotoxicity conc: With metabolic activation: Not specified 

 Without metabolic activation: Not specified 

 Genotoxic effects: + ? - 

 With metabolic activation: [ ] [ ] [X]

 Without metabolic activation: [ ] [ ] [X]

 Method: E. coli assay 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salt; activity: 99.5% 

 Remarks: Information as cited in IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Inoue, I.K. and Sunakawa, T. 1979. Mutagenicity tests of surfactants. 

Jpn Fragrance J. 38(7)(5):67-75 (in Japanese); cited in: IPCS (1996); 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) 

and Related Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

B. NON-BACTERIAL IN VITRO TEST

 Type: Transformation test with SHE-cells 

 System of testing: Syrian hamster embryo (SHE) cells 

 Concentration: up to 50 ug/mL 

 Metabolic activation: With [ ]; Without [X]; With and Without [ ]; No data [ ]

 Results: 

 Cytotoxicity conc: Without metabolic activation: 50 μg/mL 

 Genotoxic effects: 

 + ? - 

 Without metabolic activation: [ ] [ ] [X]

 Method: Cell cultures were prepared and plated in 75 cm2

 flasks containing 20 mL of 

culture medium. On day 5, target cells were trypsinized and a suspension of 

target cells was added to the solution plated on complete medium. Plates 

were dosed on day 6. Nine dishes were used for each dose level. On day 14, 

the cultures were fixed, stained, and examined to count normal and 

transformed colonies. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salts (CAS #69669-44-9); average alkyl chain length 

(based on LAS SIDS Consortium Survey, 2000) = C11.7; activity: 22.2% 

 Remarks: LAS did not produce transformation at any of the doses tested. 

 Reference: Inoue, K., Sunakawa, T., and Takayama, S. 1980. Studies of in vitro cell 

transformation and mutagenicity by surfactants and other compounds. Fd. 

Cosmet. Toxicol. 18:289-296. 

 Reliability: 2 Valid with restrictions 

5.6 GENETIC TOXICITY IN VIVO

 (a) 

 Type: Mammalian bone marrow cytogenetic assay 

 Species/strain: mouse: ICR: JCL 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: gavage 

 Exposure period: 5 days and 1 day 

 Doses: 200, 400, 800 mg/kg bw d 
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 Results: There was no significant difference in the incidence of chromosomal 

aberrations between any of the groups given LAS and the negative control 

group. 

 Control Group: Concurrent no treatment, positive and historical controls were used. 

 Method: Chromosomal aberrations were examined 6, 24, 48 hours after 

administration. Mytomycin C was used as a positive control and 

appropriately induced severe chromosomal aberrations. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS, sodium salt (CAS #69669-44-9); average alkyl chain length 

(based on LAS SIDS Consortium Survey, 2000) = 11.7 

 Remarks: Besides the pure LAS, commercial preparation containing 19% LAS and 

another containing 17.1% LAS were given to mice as single doses only by 

gavage at 800, 1600 or 3200 mg/kg bw d and 1000, 2000 or 4000 mg/kg bw 

d, respectively. The highest doses were 50% of the respective LD50 values. 

No significant differences in the incidence of chromosomal aberrations were 

observed in any LAS treatment relative to the controls. Information as cited 

in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Inoue, K., Shibata, T., Hamano, Y., Oda, Y., Kuwano, A., Yamamoto, H., 

Mitsuda, B. and Kunita, N. 1977. In vivo cytogenetic tests of some synthetic 

detergents in mice. Ann Res. Osaka Prefect Inst. Public Health. 8:17-24 (in 

Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document 

 (b) 

 Type: Mammalian bone marrow cytogenetic assay 

 Species/strain: rat (Wistar, SD); mouse (ICR) 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: oral feed 

 Exposure period: 9 months 

 Doses: 0.9% (450 mg/kg bw d in rats; 1170 mg/kg bw d in mice) 

 Results: There were no significant differences in the incidences of chromosomal 

aberrations between the experimental and control groups. 

 Method: Groups of 5 male Wistar rats, Sprague-Dawley rats, and ICR mice were 

given a diet containing 0.9% LAS for 9 months after which the chromosomes 

of the bone marrow cells were examined. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Remarks: Information as cited in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Masabuchi, M., Takahashi, A., Takahashi, O. and Hiraga, K. 1976. 

Cytogenetic studies and dominant lethal tests with long term administration 

of butylated hydroxytoluene (BHT) and linear alkylbenzene sulfonate (LAS) 

in mice and rats. Ann. Rep. Tokyo Metrop. Res. Lab. Public Health. 27:100-

104 (in Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: 

Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, 

Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 
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 (c) 

 Type: Dominant lethal assay 

 Species/strain: mouse (ICR: JCL) 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: oral feed 

 Exposure period: 9 months 

 Doses: 0.6% (300 mg/kg bw d) 

 Results: There were no significant differences in fertility, the mortality of ova and 

embryos, the number of surviving fetuses, or the index of dominant lethal 

induction between the experimental groups and the control group. 

 Method: Seven male mice received LAS in the diet for 9 months. Each of the male 

mice was then mated with 2 female mice that had not been given LAS. The 

pregnant mice were laparotomized on day 13 of gestation to determine the 

numbers of luteal bodies, implantations, surviving fetuses, and dead fetuses. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Remarks: Information as cited in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Masabuchi, M., Takahashi, A., Takahashi, O. and Hiraga, K. 1976. 

Cytogenetic studies and dominant lethal tests with long term administration 

of butylated hydroxytoluene (BHT) and linear alkylbenzene sulfonate (LAS) 

in mice and rats. Ann. Rep. Tokyo Metrop. Res. Lab. Public Health. 27:100-

104 (in Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: 

Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, 

Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (d) 

 Type: Micronucleus assay 

 Species/strain: mouse: (ddy) 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: Intraperitoneal injection 

 Exposure period: single dose 

 Doses: 100 mg/kg bw 

 Results: There were no differences in the incidences of polychromatic erythrocytes 

with micronuclei in the bone marrow cells between the treated group and the 

control group. 

 Method: Three male ddy mice were each given a single i.p. injection of 100 mg/kg bw 

LAS. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Remarks: Information as cited in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Kishi, M., Satoh, S., Horiguchi, Y. and Ito, K. 1984. Effects of 

 surfactants 

 on bone marrow cells. Bull. Kanagaw Public Health Lab. 14:57-58. (In 

Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 
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 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

5.7 CARCINOGENICITY

 (a) 

 Species/strain: Rat: Charles River 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 2 years 

 Frequency of treatment:continuous in feed 

 Doses: 0.02, 0.1, 0.5% (10, 50, 250 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ X]; Concurrent vehicle [ ]; Historical [X]

 Results: Gross examination of all animals for pathology did not reveal any 

abnormalities. No consistent dietary induced changes that could be 

considered a toxic response were observed. Animals that showed significant 

loss of weight, development of tumors, or other evidence of abnormalities 

were sacrificed and tissues examined. The incidence of tumors and the 

common incidental diseases were similar in all dieting groups. 

 Method: Four groups of Charles River weanling rats, divided by sex, were given 0.5, 

0.1, and 0.02% LAS in their food for 2 years. Following completion of those 

studies, five male and five female rats from each of the parental groups (F1b

and F2b) and all survivors were selected for necropsy. Body weight and 

organ to body weight ratios were recorded, and routine hematology and 

histology were performed. Weanling animals for the F3a generation were 

similarly treated. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS; activity: 98.1% on an anhydrous basis (41.9% active) 

 Reference: Buehler, E.V., Newmann, E.A., and King, W.R. 1971. Two year feeding 

and reproduction study in rats with linear alkylbenzene sulfonate (LAS). 

Toxicol. Appl. Pharmacol. 18:83-91. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Species/strain: Rat/Wistar 

 Sex: Female [ ]; Male [X]; Male/Female [ ]; No data [ ]

 Administration: Drinking water 

 Exposure period: 2 years 

 Frequency of treatment: Daily 

 Doses: 0.01%, 0.05%, 0.1% (20,100, 200 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 Results: There were no changes due to the administration of LAS in regard to growth, 

mortality, the weight of major organs, or histopathological findings. The 

intake of LAS was about 200 mg/kg bw d in the 0.1% group. There is no 

description of tumors. 

 Method: Groups of 20 male Wistar rats were given LAS in drinking water daily for 2 

years. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS, activity: 34.55% 

 Remarks: Information as cited in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 
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 2) Tiba, S. 1972. Studies on the acute and chronic toxicity of linear 

alkylbenzene sulfonate. J. Food Hyg. Soc. Jpn. 16:66-71 (in Japanese); cited 

in: IPCS (1996); Environmental Health Criteria 169: Linear Alkylbenzene 

Sulfonates (LAS) and Related Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document 

 (c) 

 Species/strain: Rat/Wistar 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: drinking water 

 Exposure period: up to 26 months 

 Frequency of treatment: Daily 

 Doses: 0.1% (140 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]

 Results: The administration of LAS had no effect on the intake of water, mortality, 

body weight gain, or general condition. In pathological examination, 

looseness, atrophy, and fatty change of the hepatic cells in the liver were 

found in the experimental group at 6 months. The experimental group 

showed significant increases in GOT, GTP and bilirubin at 6 months and 

thereafter. In haematological examinations no effects due to LAS were 

observed. 

 Method: A group of 62 male and 62 female rats were given drinking water treated 

with LAS and a control group of 37 male and 37 female rats were given pure 

water. Five to 12 of the rats in the experimental group and 3 to 12 rats in the 

control group at 3, 6, 12, and 18 months, respectively, and all surviving rats 

between 24 and 26 months, were sacrificed for pathological, biochemical, 

and haematological examinations. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS; mean molecular weight 348; average alkyl chain length = C12.0; 

activity: 38.74% 

 Remarks: Information as cited in the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Endo, T., Furuido, Y., Namie, K., Yamamoto, N., Hasunuma, H. and 

Ueda, K. 1980. Studies of the chronic toxicity and teratogenicity of 

synthetic surfactants. Ann. Rep. Tokyo Metrop. Res. Inst. Environ. Prot. 

236-246 (in Japanese); cited in: IPCS (1996); Environmental Health Criteria 

169: Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. 

WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (d) 

 Species/strain: Rat/Wistar 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 1, 3, 6, 24, or more months 

 Frequency of treatment: Daily 

 Doses: 0.04, 0.16, 0.6% (20, 80, 300 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]
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 Results: The 0.6% group showed slight increases in the weight of liver and cecum, 

and increased activity of GPT and ALP in serum. LAS administration had no 

adverse effects upon the intake of food, body weight gain, general condition, 

mortality or mean survival. At one month, proliferation of hepatic cells in the 

liver and slight swellings of the renal tubes and narrowing of the tubular 

lumen in the kidneys were found in the 0.16% and 0.6% groups. These 

findings later disappeared, and are considered to be adaptation phenomena to 

the administration of LAS. There were no histopathological lesions 

attributable to LAS administration in any of the organs in rats fed for 24 

months or more. Various types of tumors were observed in various organs, 

but findings suggestive of tumorigenicity of LAS were not present. 

Therefore, the authors concluded that the diet containing LAS at a 

concentration of 0.6% (300 mg/kg bw d) did not have any adverse effects on 

rats. 

 Method: Groups of 50 male and 50 female rats were given diets containing LAS at 

0.04, 0.16 and 0.6%. In each group, 5 rats of each sex were fed for 1, 3, 6, 

and 12 months, respectively, and groups of 15 rats of each sex were fed for 

24 months or more. Detailed histopathological examinations were made on 

the rats. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS; C10 10.6%, C11 34.1%, C12 27.7%, C13 19.0%, C14 8.7%; average 

alkyl chain length = C11.8; mean molecular weight 345.8 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Fujii, T., Sakamoto, Y., Abe, Y., Mikurita, H., Yuzawa, K. and Hiraga, K. 

1977. Pathological examination of rats fed with linear alkylbenzene 

sulfonate for their lifespan. Ann. Rep. Tokyo Metrop. Res. Lab. Public 

Health. 28:85-108 (in Japanese); cited in: IPCS (1996); Environmental 

Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) and Related 

Compounds. WHO, Geneva, Switzerland. 

 3) Yoneyama, M., Masubuchi, M., Oishi, S., Takahashi, O., Ikawa, M., 

Yoshida, S., Oishi, H., Mikuriya, H., Yuzawa, K. and Hiraga, K. 1977. 

Subacute toxicity of linear alkylbenzene sulfonate. Ann. Rep. Tokyo 

Metrop. Res. Lab. Public Health. 28:73-84 (in Japanese); cited in: IPCS 

(1996); Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates 

(LAS) and Related Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

5.8 TOXICITY TO REPRODUCTION

 (a) 

 Type: Fertility [ ]; One-generation study [ ]; Two-generation study [ ]; 

 Other [X] : 3-generation reproduction study 

 Species/strain: Rat: Charles River 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral feed 

 Exposure period: 2 years 

 Frequency of treatment:continuous in feed 

 Premating 

 exposure period: male: 84 days, female: 84 days 

 Duration of the test: 3 generations 

 Doses: 0.02, 0.1, 0.5% (14, 70, 350 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 
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 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [X]

 NOAEL Parental: = 0.5%. (350 mg/kg bw d) 

 NOAEL F1 Offspring: = 0.5% (350 mg/kg bw d) 

 NOAEL F2 Offspring: = 0.5% (350 mg/kg bw d) 

 Results: General reproduction including fertility gestation, parturition, neonatal 

viability, lactation, and post-weaning growth was normal for all test groups 

and did not deviate from the controls in each generation. No gross 

abnormalities were noted. No definitive adverse effects due to the test 

material were noted in the haematology and pathology. 

 Method: Na-LAS (chain length distribution C10-14) was fed for 84 days to 4 groups of 

weanling rats (3 dose levels, plus control), each dose consisting of 50 animals 

each of both sexes (PO-generation). When the P0 generation was 107-112 

days old, 20 females from each dose group were mated with 20 males from 

the same group and maintained together for 17 days. The first litters of each 

generation (Fla- and F2a-generation) were sacrificed at 21 days of age. Ten 

days after the final litter was sacrificed, all females were remated with 

different males from the same group to obtain the F1b generation. From the 

Flb-generation, 20 males and females of each group were selected at weaning 

to continue their respective diets and to be used for further reproduction 

studies. Reproduction studies on the F1b and F2b generations were started 

when the rats were 80 to 85 days old, and were continued until the F3b

generation was weaned. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Sodium salt LAS (C10-14), activity: 98.1% on an anhydrous basis (41.9% 

active) 

 Reference: Buehler, E.V., Newmann, E.A., and King, W.R. 1971. Two year feeding 

and reproduction study in rats with linear alkylbenzene sulfonate (LAS). 

Toxicol. Appl. Pharmacol. 18:83-91. 

 Reliability: 2 Valid with restrictions 

 (b) 

 Type: Fertility [ ]; One-generation study [ ]; Two-generation study [ ]; 

 Other [X] Three generation study

 Species/strain: Charles River CD strain rats 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: diet 

 Exposure period: up to > 1 year 

 Frequency of treatment:continuous in diet 

 Premating exposure 

 period: male: 60 days, female: 60 days 

 Duration of the test: 3 generations 

 Doses: 0.08, 0.4, and 2.0% continuously administered throughout the three 

generations (40, 200 and 1000 mg/kg bw d CLD [6.8, 3.4 and 170 mg/kg bw 

d LAS] 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Parental: 170 mg/kg bw d LAS (1000 mg/kg bw d CLD) 

 NOAEL F1 Offspring: 170 mg/kg bw d LAS (1000 mg/kg bw d CLD) 

 NOAEL F2 Offspring: 170 mg/kg bw d LAS (1000 mg/kg bw d CLD) 

 Results: General parental toxicity: There were no signs of malreaction to treatment 

among parents and the incidence of sporadic deaths and total litter losses 

were unrelated to dosage. Pregnancy rate and the duration of gestation were 

unaffected. Food consumption and bodyweight changes showed no 

consistent relationship to dosage over the three generations. 

 Toxicity to offspring: Examining litter parameters, statistically significant 

differences were occasionally observed but they showed no consistent dosage 
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related trends over the three generations and were considered to be unrelated 

to treatment. The incidence of malformations was unaffected by treatment. 

Additional organ weight analysis, histopathology and skeletal staining of 

representative young from the F3b generation revealed no changes that could 

be conclusively related to treatment. 

 Method: CLD was administered in the diet of the rats and new batches of diet were 

prepared each week. Males and females of each generation (Fo, F1b, and F2b) 

were kept on their respective diets for 60 days. The mating period for the 

first litter lasted 19 days. After the weaning of the first litters, approximately 

10 days, the animals were re-mated and a second litter was produced. From 

the second litters of the initial (Fo) and second (F1b) generations, 10 males and 

20 females were selected from each group at weaning in order to form the 

second and third (F2b) generations, respectively. 

 In the parent animals, observations of signs of reaction, mortalities, food 

consumption, bodyweight change, pregnancy rate, mating performance, and 

gestation period were made throughout the study. As soon as possible (< 12 

hours) after birth, all young were counted, identified by toe amputation and 

examined for external abnormalities. Up to day 21 post partum, animals 

were examined daily for dead and abnormal young. Young of the first litters 

and surplus young of the second litters were sacrificed and examined for 

abnormalities internally and externally. Rats of the F3b generation were killed 

at 3 weeks old and were also examined internally and externally for 

abnormalities. For the F3b generation, tissue from the brain, liver, heart, 

pituitary, spleen, thyroid, kidneys, thymus, adrenals, lungs, gonads, pancreas, 

bladder, bone, bone marrow, sections of the stomach, and sections of the 

small and large intestines were removed and examined. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Commercial Light Duty liquid detergent (CLD) containing 17% LAS and 7% 

alkyl ether sulfate (Lion Oil and Fat Co., Ltd.) 

 Reference: Palmer, A.K., Cozens, D.D., Batham, P., and Cherry, C.P. 1974. Effect of 

CLD on reproductive function of multiple generations in the rat. Final 

Report. Report No. LF010/731029. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Type: Fertility [ ]; One-generation study [ ]; Two-generation study [ ]; 

 Other [X] : 4-generation reproduction study 

 Species/strain: Rat/Wistar 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: drinking water 

 Frequency of treatment: Daily 

 Duration of the test: 4 generations 

 Doses: 0.1% (70 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Parental: 70 mg/kg bw d 

 NOAEL F1 Offspring: 70 mg/kg bw d 

 NOAEL F2 Offspring: 70 mg/kg bw d 

 Results: The administration of LAS had no adverse effects on fertility, parturition, 

gestation period, or lactation in any of the generations. 

 Method: Two groups of 20 rats of both sexes were given water containing LAS and 

the reproductive performance was investigated for 4 generations. Five to 10 

rats of both the control and the experimental group were sacrificed at 12 

weeks for pathological examinations. For successive reproduction, 15 males 

and 15 females produced by the first mating of rats were used. 

 GLP: Yes [ ] No [X] ? [ ]
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 Test substance: LAS; mean molecular weight 348; average alkyl chain length = C12.0. 

 Remarks: Information as cited in the IUCLID Data Set and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Endo, T., Furuido, Y., Namie, K., Yamamoto, N., Hasunuma, H. and 

Ueda, K. 1980. Studies of the chronic toxicity and teratogenicity of 

synthetic surfactants. Ann. Rep. Tokyo Metrop. Res Inst. Environ. Prot. 

236-246 (in Japanese); cited in: IPCS (1996); Environmental Health Criteria 

169: Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. 

WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

5.9 DEVELOPMENTAL TOXICITY/ TERATOGENICITY

 (a) 

 Species/strain: Rat (Wistar) and Rabbit (NZW) 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: drinking water 

 Exposure period: day 6-15 of pregnancy (rat); day 6-18 of pregnancy (rabbit) 

 Frequency of treatment: Daily 

 Doses: 0.1% (70 mg/kg bw d in rat; 250 mg/kg bw d in rabbit) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [ ]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal 

 Toxicity: Rat > 0.1% (383 mg/rat); rabbit = 0.1% (3030 mg/rabbit). 

 NOAEL teratogenicity: 0.1% for rat. 

 LOAEL teratogenicity: 0.1% (3030 mg/rabbit) 

 Results: The only effect on the dams was a slight inhibition of body weight gain in the 

rabbits. The litter parameters of both species did not show any significant 

differences from those of the controls. Delayed ossification was observed in 

rabbits, but there was no increase in malformations in either the rabbits or the 

rats. 

 Method: LAS was given to 40 rats (20 controls) and 22 rabbits (11 controls) from day 

6 to 15 (rats) and day 6 to 18 (rabbits) of pregnancy, respectively. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS; activity: 38.74%; average alkyl chain length = C12.0; (mean molecular 

weight 348) 

 Remarks: Information as cited in the IUCLID Data Set and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Endo, T., Furuido, Y., Namie, K., Yamamoto, N., Hasunuma, H. and 

Ueda, K. 1980. Studies of the chronic toxicity and teratogenicity of 

synthetic surfactants. Ann. Rep. Tokyo Metrop. Res. Inst. Environ. Prot. 

236-246 (in Japanese); cited in: IPCS (1996); Environmental Health Criteria 

169: Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. 

WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (b) 

 Species/strain: Rat: CD 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]
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 Administration: gavage 

 Duration of the test: sacrifice at day 20 of gestation 

 Exposure period: day 6 - 15 of pregnancy 

 Frequency of treatment:daily 

 Doses: 0.2, 2, 300, 600 mg/kg bw d 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal 

Toxicity: 300 mg/kg bw 

 NOAEL teratogenicity: 600 mg/kg bw 

 Results: Maternal toxicity: 

Body weight gain was retarded in the highest dose group from the start of 

dosing and showed partial recovery toward the end of the dosing period. One 

animal died in this group but it could not be conclusively related to treatment. 

The toxic effects were associated with disturbance of the gastrointestinal 

tract. Pregnancy rate was comparable at all dosages. 

Teratogenicity: 

No differences were observed among dose groups and the control group with 

respect to number of litters, viable young, litter weight, foetal weight, 

embryonic deaths, implantations, corpora lutea, pre- and post implantation 

embryonic loss, major malformations, minor visceral or embryonic loss, 

major malformations, minor visceral or skeletal anomalies or incidence of 

pups with extra ribs. 

 Method: Animals received doses by gavage daily from days 6-15 of gestation. Twenty 

animals per dose group were used. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Reference: Palmer, A.K., Readshaw, M.A. and Neuff, A.M. 1975a. Assessment of the 

teratogenic potential of surfactants (Part I) – LAS, AS and CLD. Toxicology 

3:91-106. 

 Reliability: 2 Valid with restrictions 

 (c) 

 Species/strain: Charles River CD strain rat 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Oral in distilled water 

 Duration of the test: 20 days 

 Exposure period: day 6 to day 15 of pregnancy 

 Frequency of treatment:daily 

 Doses: 0.2, 2.0, 300 and 600 mg/kg 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 300 mg/kg 

 NOAEL teratogenicity: 300 mg/kg 

 Results: Maternal toxicity: Parent animals were observed daily. Change in 

bodyweight was not affected by treatment at 0.2, 2.0, and 300 mg/kg, but 

treatment at 600 mg/kg was associated with retarded weight gain and a 

transient diarrhea following initiation of treatment. The pregnancy rate was 

comparable at all dosages. 

 Pregnancy/litter data: The litter parameters assessed included litter size, fetal 

loss and litter weight. These parameters were not significantly affected by 

any dosage. Mean pup weights were statistically higher at 0.2, 2.0 and 300 

mg/kg. 

 Teratogenicity: Embryonic and fetal development were assessed by the 

incidence of major malformations. The incidence of minor visceral 

anomalies was unaffected by treatment at any dosage. The distribution of 
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skeletal variants were not statistically significant with the exception of a 

marginal retardation of sternebral ossification at 600 mg/kg. 

 Method: After overnight mating, the rats were randomly allocated to five groups 

which included one control group and four different treatment groups. LAS 

was prepared daily as a series of graded aqueous solutions. Animals in all 

groups were dosed orally at the standard volume of 1.0 mL/100 g. Control 

animals were dosed in a similar manner with distilled water used as the 

vehicle. The dams were observed daily for signs of toxicity and weighed on 

days 1, 3, 6, 10, 14, 17 and 20 of pregnancy. On day 20, the rats were killed 

by CO2 euthanasia. Their ovaries and uterine contents were examined 

immediately for number of copora lutea, number of viable young, number of 

resorption sites, litter weight, and fetal abnormalities. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (Na salt) as a slurry containing 64.0% w/v of active ingredient (Lion Oil 

and Fat Co., Ltd.); average alkyl chain length (based on LAS SIDS 

Consortium Survey, 2002) = C11.7-12.3. 

 Reference: Palmer, A.K. and Lovell, M.R. 1971a. Effect of LAS detergent on 

pregnancy of the rat. Report No. 4331/71/487. 

 Reliability: 2 Valid with restrictions 

 (d) 

 Species/strain: Charles River Specific Pathogen Free mice of the CD-1 strain 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Oral in distilled water 

 Duration of the test: 17 days 

 Exposure period: day 6 to day 15 of gestation 

 Frequency of treatment: daily 

 Doses: 0.2, 2.0, 300, 600 mg/kg 

 Control group: Yes [ X ]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 2.0 mg/kg 

 NOAEL teratogenicity: 600 mg/kg 

 Results: Maternal toxicity: After examining parent animals, treatment at 300 and 600 

mg/kg was linked with increased mortality (35% and 90% respectively) and 

weight loss. At 600 mg/kg no dams bearing feasible young survived to 

termination. Autopsy revealed the consistent occurrence of tympanites 

sometimes associated with gastritis. 

 Pregnancy/litter data: The litter parameters were assessed by litter size, fetal 

loss and litter weight, none of which were significantly affected by treatment 

at any dosage. Mean pup weight was increased at 0.2 and 2.0 mg/kg. 

 Teratogenicity: Embryonic and fetal development was assessed by the 

incidence of major malformations and minor visceral anomalies and the 

distribution of skeletal variants. Any malformations and anomalities 

observed were not dose related. Development was not significantly affected 

at any dosage. 

 Method: After overnight mating, the mice were randomly allocated to five groups 

which included one control group and four different treatment groups. LAS 

was prepared daily as a series of graded aqueous solutions. Animals in all 

groups were dosed orally at the standard volume of 0.06 mL/10 g. Control 

animals were dosed in a similar manner with distilled water used as the 

vehicle. The dams were observed daily for signs of toxicity and weighed on 

days 1, 3, 6, 10, 14, and 17 of pregnancy. On day 17, the mice were killed by 

cervical dislocation. Their uterine contents were examined immediately for 

number of viable young, number of resorption sites, litter weight, and fetal 

abnormalities. 

 GLP: Yes [ ] No [X] ? [ ]
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 Test substance: LAS (Na salt), as a slurry containing 64.0% w/v of active ingredient (Lion 

Oil and Fat Co., Ltd.); average alkyl chain length (based on LAS SIDS 

Consortium Survey, 2002) = C11.7-12.3. 

 Reference: Palmer, A.K. and Lovell, M.R. 1971b. Effect of LAS detergent on 

pregnancy of the mouse. Report No. 4330/71/486. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Species/strain: Mouse/CD-1 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: gavage 

 Duration of the test: sacrifice at day 17 of pregnancy 

 Exposure period: days 6 - 15 of pregnancy 

 Frequency of treatment:daily 

 Doses: 0.2, 2, 300, 600 mg/kg bw d 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal 

 Toxicity: 2 mg/kg bw d 

 NOAEL teratogenicity: 300 mg/kg bw d 

 Results: Maternal toxicity: 

Among parent animals treatment at 300 and 600 mg/kg bw d was associated 

with increased mortality (35% and 90% respectively). At 300 mg/kg bw d 

weight gain was retarded only during the first four days. No assessment 

could be made at 600 mg/kg bw d, due to the high mortality rate. Necropsy 

revealed a ubiquitous occurrence of tympanites, sometimes associated with 

gastritis. Pregnancy rate was essentially comparable for all groups. 

Teratogenicity: 

At doses with no maternal toxicity, no differences were observed among the 

dose group and the control group with respect to number of litters, viable 

young, litter weight, foetal weight, embryonic deaths, implantations and post 

implantation embryonic loss. At these doses the incidences of major 

malformations and minor abnormalities were not affected. At doses with 

maternal toxicity there was an increased foetal loss and reduced litter size 

due almost entirely to total litter loss, which was considered to be a 

secondary effect due to the maternal toxicity. The incidences of major 

malformations was not affected; minor skeletal or visceral anomalies were 

increased at 300 mg/kg. 

 Method: Twenty female mice were administered 0.2, 2.0, 300, or 600 mg/kg bw of 

LAS by gavage at days 6-15 of gestation. All animals were sacrificed at day 

17 of pregnancy. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Remarks: The maternal NOAEL of 2 mg/kg bw d is considered very conservative 

because the range (2-300 mg/kg bw d) was too wide. 

Reference: Palmer, A.K., Readshaw, M.A. and Neuff, A.M. 1975a. Assessment of 

the teratogenic potential of surfactants (Part I) – LAS, AS and CLD. 

Toxicology 3:91-106. 

 Reliability: 2 Valid with restrictions 

 (f) 

 Species/strain: New Zealand white rabbit 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Gavage 

 Exposure period: day 6 to 18 of pregnancy 

 Frequency of treatment: Daily 
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 Duration of the test: sacrifice at day 29 of pregnancy 

 Doses: 0.2, 2, 300, 600 mg/kg 

 Control Group: Yes; concurrent 

 NOAEL maternal 

 toxicity: 2 mg/kg bw 

 NOAEL teratogenicity: 2 mg/kg bw 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Results: Maternal toxicity: 

 At 300 and 600 mg/kg severe maternal toxicity was observed resulting in 

 body weight loss and associated with diarrhoea, anorexia, and cachexia prior 

 to death. 

 Teratogenicity: 

 At doses with no maternal toxicity, no differences were observed among the 

dose groups and the control group with respect to number of litters, viable 

young, litter weight, foetal weight, embryonic deaths, implantations and post 

implantation embryonic loss. At these doses the incidences of major 

malformations and minor abnormalities were not affected. Higher doses 

resulted in total litter which was considered to be a secondary effect due to 

the maternal toxicity. Since there were no survivors, malformations and 

anomalies were not assessed at these doses. 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

Reference: Palmer, A.K., Readshaw, M.A. and Neuff, A.M. 1975a. Assessment of 

 the teratogenic potential of surfactants (Part I) – LAS, AS and CLD. 

Toxicology 3:91-106. 

 Reliability: 2 Valid with restrictions 

 (g) 

 Species/strain: New Zealand White rabbit 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: intragastric intubation 

 Duration of the test: 29 days 

 Exposure period: day 6 to day 18 of pregnancy 

 Frequency of treatment:daily 

 Doses: 0.2, 2.0, 300, 600 mg/kg 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal 

 Toxicity: 2.0 mg/kg 

 NOAEL teratogenicity: 2.0 mg/kg 

 Results: Maternal toxicity: Daily assessment of bodyweight change and pregnancy 

rate determined that at 0.2 and 2.0 mg/kg the treatment did not adversely 

affect parent animals. At 300 and 600 mg/kg parent animals showed signs of 

severe anorexia, diarrhoea, weight loss and death. Respective mortality rates 

were 85 and 100% and autopsy consistently revealed changes in the 

gastrointestinal tract. 

 Pregnancy/litter data: The influence of maternal toxicity restricted assessment 

of effect on litter parameters to animals treated at 0.2 and 2.0 mg/kg. At 

these two dosages there were no adverse effects on litter parameters, as 

assessed by litter size and fetal loss, litter and mean pup weights. 

 Teratogenicity: Also at these two dosages there were no adverse effects on 

embryonic and fetal development, as assessed by the incidence of major and 

minor malformations, minor anomalies and skeletal variants. 

 Method: Thirteen rabbits were mated on a one-to-one basis with males of proven 

fertility. The does were then injected intraveneously with 10 i.u. luteinizing 

hormone to ensure that ovulation occurred. The rabbits were identified by an 
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ear tag and allocated to one control group and four treatment groups. LAS 

was prepared daily and administered by intragastric intubation by a series of 

graded solutions in distilled water so that all animals were dosed at the 

standard volume of 4 mL/kg. Control animals were dosed at the same rate 

with distilled water as the vehicle. The parent animals were observed daily 

for signs of toxicity and weighed on days 1, 6, 10, 14, 21, and 28. On day 29, 

the animals were killed by cervical dislocation and immediately examined to 

determine the numbers and uterine disposition of young and resorption sites. 

The number of corpora lutea were also counted. Any rabbit containing 

abnormal fetus and/or resorption sites was thoroughly examined for signs of 

natural disease. Viable young were weighed, sexed and examined internally 

and externally for abnormalities. All young were preserved in alcohol for 

subsequent clearing, staining and skeletal examination. Resorption sites were 

classified as early or late. Abnormalities were classified as major or variant. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS (Na salt), as a slurry containing 64% active ingredient (Lion Oil and Fat 

Co., Ltd.); average alkyl chain length (based on LAS SIDS Consortium 

Survey, 2002) = C11.7-12.3. 

 Remarks: The maternal NOAEL of 2 mg/kg bw d is considered very conservative 

because the range (2-300 mg/kg bw d) was too wide. 

 Reference: Palmer, A.K. and Neuff, A.M. 1971. Effect of LAS detergent on pregnancy 

of the New Zealand white rabbit. Report No. 4387/71/543. 

 Reliability: 2 Valid with restrictions 

 

 (h) 

 Species/strain: Mouse/ICR 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: gavage 

 Duration of the test: See method. 

 Exposure period: See method. 

 Frequency of treatment:daily 

 Doses: 0.4, 4.0% (40, 400 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal 

 Toxicity: 40 mg/kg bw d 

 NOAEL teratogenicity 400 mg/kg bw d 

 Results: In mice given 400 mg/kg from day 0 to 6, the pregnancy rate was 46.2% 

compared to 92.9% in the controls. There was no increase in malformations. 

Although no information on maternal toxicity is available, it appears likely 

that maternal toxicity was present at the high dose group. 

 Method: LAS was administered from day 0 to day 6 of pregnancy or from day 7 to 13 

of pregnancy. Thirteen to fourteen mice were used in each dose group. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Japan LAS; average alkyl chain length (based on LAS SIDS Consortium 

Survey, 2002) = C11.7-12.3; activity: 99.5% 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Takahashi, M., Sato, K., Ando, H., Kubo, Y. and Hiraga, K. 1975. 

Teratogenicity of some synthetic detergents and linear alkylbenzene sulfonate 

(LAS). Ann. Rep. Tokyo Metrop. Res. Lab. Public Health 26: 67-78 (in 

Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 
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 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (i) 

 Species/strain: Mouse/ICR. 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: gavage 

 Duration of the test: see text. 

 Exposure period: day 6 through day 15 of pregnancy. 

 Frequency of treatment:daily. 

 Doses: 10, 100, 300 mg/kg bw d 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 LOAEL Maternal 

 Toxicity: 10 mg/kg bw d 

 NOAEL teratogenicity: 300 mg/kg bw d 

 Results: The dams showed inhibition of body weight gains in all groups, especially in 

the high dose group. In this group, two dams died, and there was one case of 

premature delivery and death of all fetuses. There were findings such as 

decreased body weight and delayed ossification among the living fetuses, but 

there was no increase in malformations. 

 Method: LAS was administered by gavage to 25 to 33 mice per dose on days 6 

through 15 of gestation. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Japan LAS; average alkyl chain length (based on LAS SIDS Consortium 

Survey, 2002) = C11.7-12.3; activity: 48.6% 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Shiobara, S. and Imahori, A. 1976. Effects of linear alkylbenzene 

sulfonate orally administered to pregnant mice and their fetuses. J. Food 

Hyg. Soc. Jpn. 17:295-301 (in Japanese); cited in: IPCS (1996); 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) 

and Related Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (j) 

 Species/strain: Rat: SD-JCL 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: oral feed 

 Exposure period: from day 0 to 20 of gestation 

 Frequency of treatment: Daily 

 Doses: 0.1%, 1.0% (80, 780 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 780 mg/kg bw d 

 NOAEL teratogenicity: 780 mg/kg bw d 

 Results: The LAS intake was about 780 mg/kg with the 1% diet, but there were no 

abnormalities in the body weight gains of the dams, or in the occurrence and 

maintenance of pregnancy. The values of the litter parameters did not differ 

from those of the controls and there was no evidence of teratogenicity. The 

numbers of offspring were rather low in the 1% group, and the weaning rate 

of 78.3% was lower than the 100% rate observed in the controls. However, 
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there were no abnormalities in body weight gain, organ weights or functions 

in the offspring. 

 Method: LAS was fed in the diet to 16 pregnant female rats/dose from day 0 to 20 of 

gestation. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Japan LAS; average alkyl chain length (based on LAS SIDS Consortium 

Survey, 2002) = C11.7-12.3. 

 Remarks: Information as cited in IUCLID Data Sheet and IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Tiba, S., Shiobara, S., Imahori, A. and Kitagawa, T. 1976. Effects of 

linear alkylbenzene sulfonate on dam, fetus and newborn rat. J. Food Hyg. 

Soc. Jpn. 17:66-71. (In Japanese); cited in IPCS. 1996. Environmental 

Health Criteria 169: Linear Alkylbenzene Sulfonates and Related 

Compounds. World Health Organization, Geneva, Switzerland. Original 

article in Japanese. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (k) 

 Species/strain: Weanling Charles River CD Sprague-Dawley albino rats and 

 New Zealand rabbits 

 Sex: Female [ ]; Male [ ]; Male/Female [X]; No data [ ]

 Administration: oral in feed 

 Duration of the test: two generation (rats); one generation (rabbits) 

 Exposure period: Rat: continuously or during organogenesis period of six pregnancies 

 Rabbit: day 2-16 of gestation during a single pregnancy 

 Frequency of treatment:continuous 

 Doses: Rat: 0.1, 0.5 or 1.0% TAE3S/LAS (equivalent to 50, 250 or 500 mg/kg/day in 

female rats corresponding to LAS doses of 22.5, 112.5 and 225 mg/kg bw d.) 

 Rabbit: 50, 100, or 300 mg/kg TAE3S/LAS, corresponding to LAS doses of 

22.5, 45, and 135 mg/kg bw d 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 225 mg/kg bw d LAS (rat) 

 135 mg/kg bw d LAS (rabbit) 

 NOAEL teratogenicity: 225 mg/kg bw d LAS (rat) 

 135 mg/kg bw d LAS (rabbit) 

 Results: Maternal toxicity: No treatment related adverse effects were observed in the 

maternal generation of either rats or rabbits. Fetal toxicity: No treatmentrelated adverse effects were observed on conception, fetal viability or postnatal survival in either generation of rats. Some statistically significant 

differences were observed in live-born and surviving pup numbers, but there 

were no consistent trend or patterns. Combined with the high lactation index 

in all groups, indicating a very low mortality among the suckling rats, these 

differences were considered due to causes not related to treatment with the 

test material. There were no statistical differences among the groups of rat 

fetuses taken by Caesarian section and examined for birth defects. Some 

minor soft-tissue and skeletal anomalies were observed in rat fetuses from 

both generations. Of the 1210 rat fetuses, the overall incidence of abnormal 

young was 9.0% and did not vary significantly between treatment groups or 

the controls. Similarly, no treatment-related adverse effects were seen in 

rabbits treated with the surfactant mixture. Of the 855 rabbit fetuses, 5.7% 

were abnormal, but the incidence of defective fetuses in the test groups were 

not significantly different from those in controls. Therefore, no test related 
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effects were seen on reproduction or embryonic development in either animal 

species. 

 Method: (A) Rat studies 

 The rats were divided into seven groups consisting of 25 males and 25 

females after a five day acclimation period in the laboratory. The tallow 

alkyl ethoxy sulfate (55%)-LAS(45%) mixture (TAE3S/LAS) was mixed into 

the ground commercial feed at levels of 0.1, 0.5 or 1.0% and fed to two 

generations of male and female rats continuously or only to females during 

each period of organogenesis (days 6-15) of pregnancy. A control group was 

fed the commercial feed with no additive. The parent animals body weights 

were recorded weekly for the first eight weeks in each generation and 

afterwards recorded only at each mating phase. 

 Once sexually mature, five rats of each sex per group were sacrificed for 

histology during each generation. The remaining rats were mated on a oneto-one basis three successive times during each generation. The first two 

pregnancies (F1a, 1b, 2a and 2b) in each generation were allowed to proceed to 

natural births. These pups were counted and inspected for abnormalities at 

birth. The third pregnancies in each generation (F1c and F2c) were used for 

teratology purposes. At weaning all pups except the F1b litters, which 

became the second generation parents, were discarded. Animals for the 

second generation were selected on the same basis as previously described 

for the first generation. During the third pregnancies of both generations (F1c

and F2c), one-half of each group of females was sacrificed on day 13 of 

gestation. A laparotomy was performed and the number of corpora lutea of 

pregnancy and the number of implantation and resorption sites were observed 

and recorded. On day 21 of gestation, the remaining dams were examined in 

a similar manner. 

 One-third of the fetuses in each of the third litters were examined for skeletal 

development and defects. The others were examined for soft tissue defects. 

During the teratology period, tissues were collected from five parent females 

of each group and from five parent males of the control and continuously 

treated groups. The heart, liver, kidneys and gonads were weighed, blood 

was taken for routine hemograms, and tissues were set in 10% formalin, 

paraffin-sectioned and stained with haemotoxylin-eosin for histopathy. 

 (B) Rabbit study 

 Five groups of 25 sexually mature does were distributed on the based on 

body weights and litter mates. The does were artificially inseminated with 

0.25 mL of undiluted semen, collected from sperm-tested untreated males. 

Ovulation was induced by a 1 mg/kg injection of PLH immediately prior to 

insemination. The day of insemination was considered day 0 of gestation. 

The TAE3S/LAS mixture was administered by gavage from day 2 through 

day 16 of gestation at daily doses of 50, 100, or 300 mg/kg of body weight. 

Distilled water was the vehicle and each doe received 2 mL of solution per kg 

of bodyweight. For the control groups, one received no treatment and the 

other received a treatment with water. In order to monitor the dose level, the 

females were weighed every three days. The dams were sacrificed on day 28 

of gestation and the number of corpora lutea, resorptions and live or dead 

fetuses were observed and recorded. The fetuses were removed and treated 

and examined for abnormalities. 

 GLP: Yes [ ] No [ ] ? [X]

 Test substance: A mixture of 55% tallow alkyl ethoxylate sulfate (TAE3S) and 45% LAS 

(assumed Procter and Gamble products) 

 Remarks: The authors indicate that rats received up to 6000 times the estimated “worstcase” human exposure without causing any deleterious effects on the 

development or variability of the embryo or fetus. Rabbits also received 
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doses many times the “worst-case” human dose without causing significant 

effects. 

 Reference: Nolen, G.A., Klusman, L.W., Patrick, L.F. and Geil, R.G. 1975. 

Teratology studies of a mixture of tallow alkyl ethoxylate and linear 

alkylbenzene sulfonate in rats and rabbits. Toxicology. 4:231-243. 

 Reliability: 2 Valid with restrictions 

 

 (l) 

 Species/strain: Rat: CD 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Dermal 

 Exposure period: days 2 through 15 of gestation 

 Frequency of treatment:daily 

 Doses: 0.03, 0.3, or 3% on the shaved skin as 0.5 ml aqueous solution. 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 0.3% (6 mg/kg bw d) 

 NOAEL teratogenicity: 3% (60 mg/kg bw d) 

 Results: Maternal toxicity: 

 At the high dose, local irritation was observed resulting in a slightly lower 

body weight gain and hypersensitivity (i.e., animals were increasingly 

irritable). 

 Teratogenicity: 

 No differences were observed among the dose groups and the control group 

with respect to number of litters, viable young, litter weight, foetal weight, 

embryonic deaths, implantations, corpora lutea, or pre- and post implantation 

embryonic loss. The incidences of major malformations, minor visceral or 

skeletal anomalies, and skeletal variants were not different between controls 

and dose groups even at maternal by toxic doses. 

 Method: The dosage volume was 0.5 mL which was applied to an area of skin (4x4 

cm) from which the fur was removed. The nominal doses were 0.6, 6.0, and 

60 mg/kg bw d. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Japan LAS; average alkyl chain length (based on LAS SIDS Consortium 

Survey, 2002) = C11.7. 

 Reference: Palmer, A.K., Readshaw, M.A. and Neuff, A.M. 1975b. Assessment of the 

teratogenic potential of surfactants (Part III) – Dermal application of LAS 

and soap. Toxicology 4:171-181. 

 Reliability: 2 Valid with restrictions 

 

 (m) 

 Species/strain: Rat/Wistar 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Dermal 

 Duration of the test: sacrifice at day 21 of gestation 

 Exposure period: 21 days (days 0 through 21 of gestation) 

 Frequency of treatment:Daily 

 Doses: 0.05, 0.1, and 0.5% (0.1, 2 and 10 mg/kg bw d) or 1.0, 5.0, and 20% (20, 100, 

and 400 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 1% (20 mg/kg bw d) 

 NOAEL teratogenicity: 20% (400 mg/kg bw d) 

 Results: Maternal toxicity: 

The dams treated with 20% and 5% showed inhibition of body weight gain 

and local skin effects. 
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Teratogenicity: 

There were no indications of teratogenic or embryotoxic effects at any level 

in either group tested. 

 Method: LAS was applied to depilated areas on the chests and backs of female rats 12-

18 weeks of age. Five to six hours prior to treatment an exposure site 

(roughly 24 cm2

) in the dorsothoracic region of each animal from group II 

through IX was clipped to a length of 1 mm. The animals were reclipped 

every 48 hr throughout the study. Group I animals were unclipped, group II 

animals were clipped but not treated and group III animals were clipped and 

treated with tap water. The mated female rats were treated daily from day 0 

through day 20 of gestation. A 0.5-ml sample of the appropriate 

concentration of LAS and/or tap water was applied once daily to the clipped 

area and spread with a gloved finger over as much of the exposure site as 

possible. Each application was carried out slowly over a 3-min period. In 

the 1, 5 and 20% LAS groups (groups VII, VIII and IX, respectively 

corresponding to 20, 100 and 400 mg/kg/day) the test material was allowed 

to remain on the backs of the animals for 30 min. after which it was removed 

with warm tap water. The test material was not removed from the backs of 

the animals in the 0.05, 0.1 and 0.5% LAS groups (groups IV, V and VI 

corresponding to 1, 2 and 10 mg/kg/day). Animal body weight and food 

consumption were determined during the treatment period. Daily 

observations were also made for toxicological effects. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS; mean chain length: 11.7; mean molecular weight: 344, activity: 

20.5% 

 Reference: Daly, I.W., Schroeder, R.E. and Killeen, J.C. 1980. A teratology study of 

topically applied linear alkylbenzene sulphonate in rats. Fd. Cosmet. 

Toxicol. 18:55-58. 

 Reliability: 2 Valid with restrictions 

 

 (n) 

 Species/strain: Mouse/CD-1 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Dermal 

 Exposure period: days 2 through 13 of gestation 

 Frequency of treatment:daily 

 Doses: 0.03, 0.3, or 3% LAS in aqueous solution onto the shaved skin (5, 50 and 500 

mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 0.03% (5 mg/kg bw d) 

 NOAEL teratogenicity: 0.3% (50 mg/kg bw d) 

 Results: Maternal toxicity: 

 At the high dose, severe local irritation was observed resulting in body 

weight loss and hypersensitivity (i.e., animals were increasingly irritable), 

which was also observed at the medium dose. The conclusion of the authors 

was that LAS caused marked toxicity at the high dose and moderate or mild 

toxicity at the medium dose. 

 Teratogenicity: 

 At the lowest dose, the dose with no maternal toxicity, no differences were 

observed among the LAS group and the control group with respect to number 

of litters, viable young, litter weight, foetal weight, embryonic deaths, 

implantations, corpora lutea, pre- and post implantation embryonic loss. The 

incidences of major malformations, minor visceral or skeletal anomalies, and 

skeletal variants were not different between controls and the LAS group. 
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 Maternally toxic dosages were associated with a significantly increased foetal 

loss and consequent reduction of litter size. This was due almost entirely to 

total litter losses as values, for the one surviving litter at 3% was similar to 

the control litters. At the medium dose, the moderate degree of maternal 

toxicity correlated with a moderate effect on litter values in that, whilst the 

higher incidence of embryonic deaths differed significantly from control 

values, the consequent reduction in litter size was not statistically significant. 

With regard to major malformations and minor skeletal or visceral anomalies, 

the assessment of litters was not possible in the highest dose group due to the 

low survival. At the low doses, no treatment related increase of the 

incidences of major malformations and minor skeletal and visceral anomalies 

were observed. 

 Method: The dosage volume was 0.5 mL which was applied to an area of skin (2 x 3 

cm) from which the fur was removed. The nominal doses were 5, 50, and 

500 mg/kg bw/day. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: Japan LAS; average alkyl chain length (based on LAS SIDS Consortium 

Survey, 2002) = C11.7-12.3. 

 Reference: Palmer, A.K., Readshaw, M.A. and Neuff, A.M. 1975b. Assessment of the 

teratogenic potential of surfactants (Part III) Dermal application of LAS and 

soap. Toxicology. 4:171-181. 

 Reliability: 2 Valid with restrictions 

 

 (o) 

 Species/strain: mouse: ddy. 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Dermal 

 Exposure period: day 0 through day 13 of pregnancy 

 Frequency of treatment:Daily 

 Doses: 2.2% (110 mg/kg bw d) 

 Control group: Yes [ ]; No [ ]; No data [X]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 2.2% (110 mg/kg bw d) 

 NOAEL teratogenicity: 2.2% (110 mg/kg bw d) 

 Results: No abnormalities were seen in the dam or fetuses. 

 Method: An area of 4 x 4 cm on the backs of mice was depilated and LAS was applied 

at a dose of 0.5 ml/mouse/day. Sixteen animals were used per group. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS; molecular wt = 346; average alkyl chain length = 11.8; activity: 99.5% 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Sato, K., Ando, H., Yuzawa, K. and Hiraga, K. 1972. Studies on toxicity 

of synthetic detergents (III) Examination of teratogenic effects of alkyl 

benzene sulfonates spread on the skin of mice. Ann. Rep. Tokyo Metrop. 

Res. Lab. Public Health. Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 

 (p) 

 Species/strain: mouse/ICR 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: dermal 
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 Exposure period: from day 6 through day 15 of pregnancy 

 Frequency of treatment: daily 

 Doses: 0.03, 0.3, 3% (15, 150, and 1500 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 0.3% (150 mg/kg bw d) 

 NOAEL teratogenicity: 3% (1500 mg/kg bw d) 

 Results: The 3% group showed a clear decrease in the pregnancy rate (67.9%) when 

compared with a rate of 96.3% in the controls. However, there were no 

decreases in the litter size, and no changes in the litter parameters with the 

exception of a slight decrease in fetal body weight. There were no significant 

increases in the incidence of malformations in the fetuses. 

 Method: Areas of 4 x 4 cm on the backs of the mice were depilated and aqueous 

solutions of LAS were applied. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: C10-14 LAS (CAS #69669-44-9); average alkyl chain length (based on LAS 

SIDS Consortium Survey, 2002) = C11.7; activity: 46.6% 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Imahori, A., Kinagawa, T. and Shiobara, S. 1976. Effects of linear alkyl 

benzene sulfonate (LAS) applied dermally to pregnant mice and their fetuses. 

Jpn. J. Public Health. 23:68-72 (in Japanese); cited in IPCS (1996); 

Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) 

and Related Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (q) 

 Species/strain: mouse/ICR 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Subcutaneous injection 

 Exposure period: Day 0 to 3 or day 8 to 11 of pregnancy 

 Frequency of treatment: daily 

 Doses: 0.35, 1% in water (20, 200 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 0.35% (20 mg/kg bw d) 

 NOAEL teratogenicity : 1% (200 mg/kg bw d) 

 Results: When dams were administered the 1% solution from day 0 to 3 of pregnancy, 

there was an initial decrease in body weight and necrosis at the injection 

sites. The number of pregnancies decreased in the mice given the 1% 

solution compared to the controls (61.5% vs. 93.3%) There were no 

significant changes with respect to litter parameters, major malformations or 

minor abnormalities. 

 Method: LAS was injected at doses of 20 mL/kg/day from day 0 to 3 or day 8 to 11 of 

pregnancy. There were 12 - 19 mice in each treatment group. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS, activity: 99.5% 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Takahashi, M., Sato, K., Ando, H., Kubo, Y. and Hiraga, K. 1975. 

Teratogenicity of some synthetic detergents and linear alkylbenzene sulfonate 

(LAS) Ann. Rep. Tokyo Metrop. Res. Lab. Public Health 26:67-78 (in 
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Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: Linear 

Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, 

Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document 

 (r) 

 Species/strain: rabbit/New Zealand white 

 Sex: Female [X]; Male [ ]; Male/Female [ ]; No data [ ]

 Administration: Dermal 

 Exposure period: 17 days (days 1 through 16 of gestation) 

 Frequency of treatment: Daily 

 Doses: 0.03, 0.3, or 3% (0.9, 9, or 90 mg/kg bw d) 

 Control group: Yes [X]; No [ ]; No data [ ]; 

 Concurrent no treatment [X]; Concurrent vehicle [ ]; Historical [ ]

 NOAEL Maternal: 0.03% (0.9 mg/kg bw d) 

 NOAEL teratogenicity: 3% (90 mg/kg bw d) 

 Results: Maternal toxicity: 

 At the high dose, local irritation was observed resulting in body weight loss 

and hypersensitivity (i.e., animals were increasingly irritable). The medium 

dose caused retarded body weight gain and hypersensitivity. 

 Teratogenicity: 

 At the medium and low dose, no differences were observed among the dose 

groups and the control group with respect to number of litters, viable young, 

litter weight, foetal weight, embryonic deaths, implantations, corpora lutea, 

pre and post implantation embryonic loss. The high dose was associated with 

slightly, but not significantly, higher foetal loss and lower litter size. The 

incidences of major malformations, minor visceral or skeletal anomalies, and 

skeletal variants were not different between controls and dose groups even at 

maternal toxic doses. 

 Method: The dosage volume was 10 mL which was applied to an area of skin (12 x 20 

cm) from which the fur was removed. The nominal doses were 0.9, 9.0, and 

90 mg/kg bw/day. Thirteen rabbits per dose were used. 

 GLP: Yes [ ] No [X] ? [ ]

 Test substance: LAS 

 Reference: Palmer, A.K., Readshaw, M.A. and Neuff, A.M. 1975b. Assessment of the 

teratogenic potential of surfactants (Part III) – Dermal application of LAS 

and soap. Toxicology 4:171-181. 

 Reliability: 2 Valid with restrictions

5.10 OTHER RELEVANT INFORMATION 

(a) 

Type: Toxicokinetics 

Results: 35S-LAS (15 x 108

 cpm) was administered topically, once, onto the back skin 

of rats and guinea pigs. Absorption and distribution in major organs and 

blood were studied. Urine was collected 24 hours after topical application of 

the test substance. In the guinea pig, the amount of 35S excreted in the urine 

was about 0.1% of the total administered dose. Organ distribution in the rat 

was about 5 times greater than in the guinea pig, and "relatively large 

amounts" of 35S were noted in the liver and kidneys. Conclusion states that: 

"when 0.2 to 0.5% LAS was topically applied once, approximately 0.1 to 

0.6% was absorbed"; there was no accumulation in specific organs; the "test 

chemical was quickly excreted in the urine after being metabolized". 
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Reference: Debane, C. 1978. National Hygiene Laboratory; in: "Report on Studies on 

Synthetic Detergents", October 1978, Japan's Science and Technology 

Agency [in Japanese]. 

Reliability: 4 Not assignable 

(b) 

 Type: Toxicokinetics 

 Method: The absorption, distribution, metabolism and elimination of LAS 

(radioactively labelled with 35S) were studied in male Charles River rats. 

LAS was administered as an aqueous solution. 

 Results: The compound was readily absorbed from the gastrointestinal tract (80-90% 

of the dose). Most of the absorbed 35S was eliminated within 72 hours and 

60-65% of the absorbed dose was eliminated in the urine, with sulfophenyl 

butanoic and sulfophenyl pentatonic acid as metabolites. These metabolites 

were not reabsorbed from the kidney tubules. 35% of the absorbed 35S was 

excreted in the bile and were reabsorbed completely from the gastrointestinal 

tract. Although the metabolites in the bile were not identified, it was shown 

that no unchanged LAS was eliminated via this pathway. 

 Test substance: C10-13, LAS (CAS #68411-30-3); alkyl chain length predominately C11, C12

and C13. 

 Remarks: The authors suggested that metabolism proceeded via omega oxidation with 

subsequent beta-oxidation. Retention of radioactivity was not observed in 

any organ. 

Reference: Michael, W.R. 1968. Metabolism of linear alkylate sulfonate and alkyl 

benzene sulfonate in albino rats. Toxicol. Appl. Pharmacol. 12:473-485. 

Reliability: 2 Valid with restrictions 

 

 (c) 

 Type: Toxicokinetics 

 Results: LAS is well absorbed by via the gastrointestinal tract of pigs treated with 3.3 

mmol/animal 35S-Na-dodecylbenzene sulfonate. At 200 hours after oral 

administration, the radioactivity was relatively high in bristles and bones, 

while low in liver, kidney and spleen. After 10 weeks only traces of 

radioactivity were still in the body. 40 hours after the administration, 40% of 

the dose was excreted into the urine and 60% of the dose via the faeces. 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Havermann, H. and Menke, K.H. 1959. Biological study of the watersoluble surface-active substances. Fette. Seifen. Anstrichmittel 61:429-434. 

(in German); cited in IPCS. 1996. Environmental Health Criteria 169: 

Linear Alkylbenzene Sulfonates and Related Compounds. World Health 

Organization, Geneva, Switzerland. Original article in Japanese. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 

 (d) 

 Type: Toxicokinetics 

 Results: Four (2 male, 2 female; 5 kg average body weight) adult rhesus monkeys 

(Macaca mulatta) were given single or repeated oral (30, 150 or 300 mg/kg) 

or subcutaneous (0.1, 0.5 or 1 mg/kg) doses of 14C-LAS. After single 30 

mg/kg oral doses the radioactivity was rapidly excreted, mostly during the 

first 24 hours. Means of 71.2% and 23.1% of the dose were excreted in the 

urine and feces, respectively, during 5 days. Similarly, after single 1 mg/kg 

subcutaneous doses, means of 64.1% and 10.9% were excreted in urine and 
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feces, respectively, during 5 days, mostly during the first 24 hours. After 

single oral doses of 30, 150 and 300 mg/kg, peak plasma concentrations (at 4 

hours in all cases) were very similar, with levels of 34, 41 and 36 μg/mL, 

respectively. Concentrations declined during the period of 6-24 hours, with a 

biological half life of about 6.5 hours. After single subcutaneous doses of 

0.1, 0.5 and 1 mg/kg, peak plasma concentrations increased almost 

proportionately, with levels of 0.16, 0.72 and 1.13 μg/mL, respectively. 

During the 120 hours after single oral (30 mg/kg) or subcutaneous doses (1 

mg/kg) the average rate of excretion was between 63 and 74% in the urine 

and between 9 and 26% in the feces. 

 During seven consecutive daily oral (30 mg/kg/day) or subcutaneous (1 

mg/kg/day) doses, there was no accumulation of radioactivity in plasma. 

Mean peak concentrations and biological half-lives were similar after the first 

and seventh doses. Two hours after the last dose, the highest radioactivity 

was observed in the stomach. Radioactivity was also observed in the 

intestinal tract, kidneys, liver, lung, pancreas, adrenals and pituitary. At 24 

hours, concentrations were highest in the intestinal tract, probably indicating 

biliary excretion. Since the concentrations in the tissues in general were 

lower than in plasma, no specific accumulation of LAS occurred. When 14CLAS was injected into the skin, most of the radioactivity remained at the site 

of injection. No localization of radioactivity in any tissue occurred. No 

unchanged LAS was detected in urine samples after oral or subcutaneous 

doses (either single or repeated). 

Five metabolites were excreted but they were not identified. Incubations 

with beta-glucuronidase/sulfatase did not affect the metabolites, indicating 

that the metabolites were probably not present as the corresponding 

conjugates. 

 Test substance: Alkyl benzene sulfonate, sodium salt; mean molecular weight 349 (supplied 

by the Japan Soap and Detergent Association) 

 Reference: Cresswell, D.G., Baldock, G.A., Chasseaud, L.F. and Hawkins, D.R. 1978. 

Toxicological studies of linear alkylbenzene sulfonate (LAS) in rhesus 

monkeys: (II) the disposition of [14C] LAS after oral or subcutaneous 

administration. Toxicology 11:5-17. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Type: Toxicokinetics 

 Results: Rats were dosed orally with 14C-Na-LAS and radioactivity was detected 0.25 

hr after administration, reaching a maximum at 2 hrs. The biologically half 

lives were calculated to be 10.9 hrs. The distribution was high in the 

digestive tract and in the bladder at 4 hours after administration. 

Concentrations were also high in the liver, kidney, testis, spleen and lung. 

168 hours after the administration, the rates of excreted radioactivity were 

47% in the urine and 50% in the faeces 

 Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Sunakawa, T., Ikida, Y. and Okamoto, K. 1979. Absorption, distribution, 

metabolism, and excretion of linear alkylbenzene sulfonate in rats. J. Jpn. Oil 

Chem. Soc. 39:59-68 (in Japanese); cited in: IPCS (1996); Environmental 

Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) and Related 

Compounds. WHO, Geneva, Switzerland. 

 Reliability: 4 This study is assigned a reliability score of 4 because the original report 

was not available for review. However, the study was evaluated by IPCS 

prior to inclusion in their criteria document. 
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(f) 

 Type: Toxicokinetics 

 Method: Studies were conducted with isolated human skin preparations as well as in 

vivo investigations of percutaneous administration of LAS to rats. Two C12

LAS solutions were tested: a 3 mM solution in 25% v/v polyethylene glycol 

400 in water, and a 3 mM suspension in water prepared by homogenizing and 

equilibration in an all-glass homogenizer. 

 Results: No radioactivity was detected in urine or faeces. 

 Test substance: LAS (CAS #25155-30-0); activity: >99% 

 Remarks: These studies demonstrated that penetration through skin and subsequent 

systemic absorption of this surfactant does not occur to any significant extent 

at 24 to 48 hrs. 

 Reference: Howes, D. 1975. The percutaneous absorption of some anionic surfactants. 

J. Soc. Cosmet. Chem. 26:47-63. 

 Reliability: 2 Valid with restrictions 

 

 (g) 

 Type: in vitro studies with fertilised eggs 

 Method: Eggs from B6 x C3F1 female mice, which were fertilised in vitro with sperm 

from C3 x 101F1 male mice, were treated with LAS for 1 hour at the 

pronucleus stage and then cultivated for 5 days. 

 Results: Eggs treated with LAS at concentrations of less than 0.025% developed to 

the blastocyst stage as well as the untreated ones. At higher concentrations 

no egg developed beyond the 1-cell stage. The group that was treated with 

natural soap had no effect up to a concentration of 0.05%. 

 Test substance: Commercial LAS detergent (Japan) 

 Remarks: The authors suggest that LAS interrupts mouse pregnancy by killing 

fertilized eggs, however, the relevance of the results obtained in this assay for 

the in vivo situation has not been proven. 

 Reference: Ishii, Y., Samejima, Y., Saji, F. and Nomura, T. 1990. Effect of alcohol 

sulfate, linear alkylbenzene sulfonate, and natural soap on the development of 

fertilized eggs of the mouse in vitro. Mutat. Res. 242:151-155. 

 Reliability: 2 Valid with restrictions 

5.11 EXPERIENCE WITH HUMAN EXPOSURE

 (a) 

 Type: Human Repeat Insult Patch Test 

 Number of Subjects: 95 (at completion) 

 Methods: LAS was applied at 0.10% (w/v) on the upper arms of volunteers, under 

occlusive patch conditions. Test material was applied for 24 hours, 3 times a 

week, for 3 weeks during the induction period. After a 14-17-day rest, a 24-

hour challenge patch was applied on the original and alternate arm sites. 

 Results: There was no evidence of skin sensitization on the 95 subjects who 

completed the test.

 Test Material: LAS; activity: 30.0% 

 Reference: The Procter & Gamble Company, unpublished data, Report No. ISC-124-

0470. 

 Reliability: 4 Not assignable 

 

(b) 

 Type: Human Repeat Insult Patch Tests. 

 Number of subjects: 2,294 (exposed to LAS as a raw material) 

 17,887 (exposed to LAS in formulations) 

 Results: No evidence of skin sensitization. 
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 Reference: Nusair, T.L., Danneman, P.J., Stotte, J., and Bay, P.H.S. 1988. Consumer 

products: Risk assessment process for contact sensitization. Toxicologist 

8:258. (abstract). 

 Reliability: 4 Not assignable 

 

(c) 

 Type: Occlusive epicutaneous 

 Results: LAS was applied at 1% once to middle Europeans for 24 hours. Test 

duration was 6 days. The authors concluded that LAS was sufficiently 

compatible to the skin. 

 Remarks: Information as cited in the IUCLID Data Sheet. 

 Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs., 

sodium salts. Year 2000 CD-ROM edition. 

 2) Matthies, W., Henkel KgaA, unpublished data, Report No. 890356 (1989). 

 Reliability: 4 Not assignable 

 (d) 

 Type: Comparison of human experience to eye exposure to surfactants with animal 

eye irritation studies 

 Methods: Summaries of human manufacturing accident and consumer accident eye 

irritation incidents over several years were collected for laundry, household 

and personal cleaning products. These summaries included the date the 

incident occurred, the exact product or formulation involved, the estimated 

time for the eyes to return to normal, and a brief description of the eye 

response. A total of 231 manufacturing employee incidents and 284 

consumer incidents were usable, covering 24 and 23 different products, 

respectively. The results of these human contact incidents were compared to 

the results of studies conducted using two rabbit eye irritation procedures 

commonly used to assess eye irritation. These two methods are briefly 

summarized below: 

1. The FHSA (modified Draize) test utilized albino rabbits, which were 

dosed into the conjunctival sac with 0.1 mL of liquid product or the 

weight of the solid product equivalent to 0.1 cc. The eyelids were held 

shut for one second after instillation. The animals were observed at 1, 2, 

3, 4, 7, 14 and 21 days or longer. 

2. The Griffith low-volume eye irritation test utilized albino rabbits, with 

the test substances dosed directly on the cornea with 0.01 mL of liquid 

product or the weight of solids equivalent to 0.01 cc. The eyelid was 

released immediately after dosing without forced closing. The animals 

were observed for the same time periods as above. 

 Results: Median days-to-clear for human accident eye exposure are minimal. Only 

one product was as high as 7 days and the rest were 2 days or less. A total of 

88.1% of the eyes cleared in 4 days or less. There was no reported 

permanent eye damage. Both of the animal methods produced more severe 

eye responses than were reported from human eye accidents with the same 

consumer products (Freeberg et al. 1984). 

 Remarks: Animal studies consistently overestimated the human response to accidental 

exposure. Of the two animal methods, the low-volume rabbit test gave a 

closer correlation, while the FHSA test gave the least correlation. A followup study published in 1986 confirmed this conclusion. Finally, an additional 

paper published in 1995 compared consumer eye irritation comments from 

1985 to 1992 with the results of low volume eye tests (LVET). The clinical 

data and consumer experience consistently showed less eye irritation in 

humans from exposure to products than was observed in animal studies. 
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Recovery in humans was similar to that reported previously, supporting 

milder irritation response and faster healing in humans than in rabbits. 

 Reference: Freeberg, F.E., Griffith, J.F., Bruce, R.D., and Bay, P.H.S. 1984. Correlation 

of animal test methods with human experience for household products. J. 

Toxicol.- Cut. & Ocular Toxicol. 1:53-64. 

 Freeberg, F.E., Hooker, D.T., and Griffith, J.F. 1986. Correlation of animal 

eye test data with human experience for household products: an update. J. 

Toxicol.- Cut. & Ocular Toxicol. 5:115-123. 

 Cormier, E.M., Hunter, J. E., Billhimer, W., May, J., and Farage, M.A. 1995. 

Use of clinical and consumer eye irritation data to evaluate the low-volume 

eye test. J. Toxicol.- Cut. & Ocular Toxicol. 14:197-205. 

 Reliability: 2 Valid with restrictions 

 (e) 

 Type: Characterization of aerosols generated from a consumer spray product 

 Methods: The study was designed to evaluate size distribution of aerosols suspended in 

air after normal use of consumer spray products. Size distribution of 

aerosols generated from six different consumer trigger spray product nozzles 

was measured using a laser diffraction particle sizer (Mastersizer Model X, 

Malvern Instruments Ltd). A 300 mm receiving lens was used, which covers 

a particle size range of 1.2-600 microns. The exit of the trigger sprayer was 

positioned at 20 mm from the lens to the center of the device to avoid 

vignetting, and 120 mm from the laser beam axis to the tip of the trigger 

sprayer to avoid its interference with the laser beam. Measurements were 

repeated 5 times for each sprayer. 

 Results: The overall mean (n=30) particle size is 0.11% particles under 10 microns, 

with a standard deviation of 0.21. The very highest observation was 0.80%. 

Under normal use conditions, the peak breathing zone concentration under 

10 microns ranged from 0.13 to 0.72 mg/m3

. 

 Remarks: This testing only captured the spray particles that are under 600 microns, so 

the actual percentage of total volume sprayed is less than 0.1%. 

 Reference: Battelle. 1999. Measurement and Characterization of Aerosols Generated 

from a Consumer Spray Product – Pilot Study. Prepared for The Soap and 

Detergent Association. Battelle Study No. N003043A, January 18, 1999. 

 Reliability: 1 Valid without restriction 

 (f) 

 Type: Modeling of dose observed from inhalation of aerosols 

 Methods: The worst case air concentration of LAS resulting from use in surface 

cleaning spray products was modeled using methods recommended by the 

HERA Guidance Document (06/2001). In this modeling, HERA reports the 

results of experimental measurements of the concentration of aerosol 

particles from a 2001 Procter & Gamble study. The following algorithm was 

used to model the absorbed dose: 

 Expsys = F1 · C’ · Qinh · t · n · F7 · F8/bw (mg/kg bw/day) 

 Where: 

 Expsys = dose absorbed via inhalation 

 F1 = weight fraction of substance in product = 6% (worst case assumption) 

 C’ = product concentration = 0.35 mg/m3

 Qinh = ventilation rate of user = 0.8 m3

/hr 

 t = duration of exposure = 0.17 hr (10 minutes) 

 n = product use frequency, in number of events per day = 1 

 F7 = weight fraction respirable = 100% 

 F8 = weight fraction absorbed or bioavailable = 75% 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 309

 bw = body weight = 60 kg 

 Results: The modeling resulted in an Expsys (inhalation of aerosols) = 0.04 μg/kg 

bw/day. Measured aerosol particles under 6.4 microns in size were 

generated upon spraying with typical surface cleaning spray products, 

resulting in a product concentration of 0.35 mg/m3

. 

 Reference: HERA. 2002. HERA-LAS Human and Environmental Risk Assessment: 

Linear Alkylbenzene Sulphonates, LAS. CAS No. 68411-30-3, Draft, July 

2002. http://www.heraproject.com/riskassessment.cfm

 Reliability: 4 This score was assigned because the original Procter & Gamble study and 

the HERA model inputs were not available for review. However, the study 

and all assumptions were evaluated by HERA. 
OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS) 

UNEP PUBLICATIONS 310

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APPENDIX A 

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