http://www.epa.gov/oppt/newchems/chemcat.htm 

TSCA NEW CHEMICALS PROGRAM

(NCP)

CHEMICAL CATEGORIES

Contact:

Office of Pollution Prevention and Toxics

U.S. Environmental Protection Agency

1200 Pennslyvania Avenue, N.W

Washington, D.C. 20460

Telephone: (202) 564-8996

Miriam Wiggins-Lewis (mail code 7405M; wigginslewis.miriam@epa.gov)

J. Vincent Nabholz (mail code 7403M; nabholz.joe@epa.gov)

Rebecca Jones (mail code 7403M; jones.rebecca@epa.gov)

Last revised: October, 2002
Note on Test Guidelines Cited in this Document: 

This document contains references to test guidelines that originally appeared in title 40, chapter 

I, subchapter R of the Code of Federal Regulations (CFR). Since that time, the "OPPTS 

Harmonized Test Guidelines" have been developed by EPA's Office of Prevention, Pesticides 

and Toxic Substances for use in the testing of pesticides and toxic substances, and the 

development of test data that must be submitted to the Agency for review under Federal 

regulations. These guidelines can be found at http://www.epa.gov/docs/OPPTS_Harmonized/. 

Until we fully update all the references contained within this categories document, you can find 

any new OPPTS guideline that corresponds to an old CFR citation. For example, the fish acute 

toxicity test at 40 CFR 797.1400 has been replaced by OPPTS 850.1075, and Ready 

Biodegradability at 40 CFR 796.3180, etc. has been replaced by OPPTS 835.3110. 

Disclaimer: 

EPA's Office of Pollution Prevention and Toxics (OPPT) groups chemicals with shared chemical 

and toxicological properties into categories so that PMN reviews are facilitated. PMN 

submitters and EPA reviewers benefit from the accumulated data and past decisions represented 

by a category. EPA considers all PMNs, including new chemical substances which fall within 

such categories, on a case-by-case basis and uses the most appropriate structural analogue to 

support any concerns for health or environmental effects. For any new chemical substance, if 

EPA determines, under TSCA section 5(e), that the substance "may present an unreasonable risk 

of injury to health or the environment,” the PMN substance can be subjected to appropriate 

control actions and/or testing under TSCA section 5(e). This “may present” finding is developed 

through the application of category-based or chemical-by-chemical assessment of hazard 

endpoints and case-specific exposure assessment. 

The categories included in this compilation represent chemicals for which sufficient assessment 

experience has been accumulated so that hazard concerns and testing recommendations vary 

little from chemical to chemical within the category. Thus, these categories do not necessarily 

represent the chemicals of greatest concern to the Agency. By the same token, the categories are 

also not intended to be a comprehensive list of all substances that may be subject to further 

action in the New Chemicals Program. 

If a new chemical substance is structurally similar to a substance for which EPA has positive 

toxicity data and there is sufficient exposure, EPA may regulate that substance under section 5(e) 

of the Toxic Substances Control Act (TSCA) based on its potential unreasonable risk. The 

hazard potential of a PMN substance is dependent on the molecular weight of the compound, the 

presence/absence of activating/deactivating substituents, other physical/chemical properties, and 

the likely route of exposure. Typically, concerns are confined to chemicals with molecular 

weights <1,000 whenever inhalation exposure to humans or environmental release is expected, 

and to species <500 when dermal exposure to humans is expected. 

Additional information on testing conditions and testing options for specific PMN chemical 

substances that appear to fall within one of these categories is available by contacting the New 

Chemicals Branch at 202-260-3725 or the TSCA Hotline at 202-554-1404. This is to serve only 

ii 
as a guide for PMN submitters. PMN submitters are urged to have protocols and testing schemes 

evaluated by the New Chemicals Program prior to commencing testing on a PMN substance. 

However, under no circumstance does such an evaluation mean that the new chemical substance 

is not subject to further review during any TSCA section 5 review period for the PMN substance 

or that additional testing or regulatory action may not be recommended. Finally, even if EPA 

does not make the potential unreasonable risk finding for a new chemical substance, the Agency 

may still recommend the use of engineering controls or personal protective equipment to reduce 

exposures in the workplace if the PMN substance is a potential irritant or sensitizer. 

iii 
Table of Contents 

Acid Chlorides ................................................................1

Acid Dyes and Amphoteric Dyes .................................................2

Acrylamides ..................................................................5

Acrylates/Methacrylates ........................................................8

Aldehydes ..................................................................10

Aliphatic Amines .............................................................14

Alkoxysilanes ................................................................16

Aluminum Compounds ........................................................18

Aminobenzothiazole Azo Dyes ..................................................23

Anhydrides, Carboxylic Acid ...................................................25

Anilines ....................................................................26

Dianilines .............................................................30

Anionic Surfactants ...........................................................34

Azides .....................................................................36

Benzotriazoles ...............................................................39

Benzotriazole-hindered phenols .................................................42

Boron Compounds ............................................................45

Cationic Dyes ................................................................50

Cationic (quaternary ammonium) surfactants .......................................51

Cobalt ......................................................................52

Diazoniums .................................................................56

Dichlorobenzidine-based Pigments ...............................................60

iv 
Dithiocarbamates .............................................................62

Epoxides ....................................................................64

Esters ......................................................................65

Ethylene Glycol Ethers ........................................................68

Hydrazines and Related Compounds ..............................................70

Hindered Amines .............................................................73

Imides ......................................................................74

Diisocyanates ................................................................77

$-Naphthylamines, Sulfonated ..................................................80

Lanthanides or Rare Earth Metals ................................................82

Neutral Organics .............................................................86

Nickel Compounds ............................................................88

Nonionic Surfactants ..........................................................90

Organotins ..................................................................92

Peroxides ...................................................................96

Persistent, Bioaccumulative, 

and Toxic (PBT) Chemicals...................................98

Phenolphthaleins ............................................................101

Phenols ....................................................................103

Phosphates, Inorganic ........................................................106

Phosphinate Esters ...........................................................109

Polyanionic Polymers (& Monomers) ............................................112

Polycationic Polymers ........................................................113

Polynitroaromatics ...........................................................114

v 
Respirable, Poorly Soluble Particulates ...........................................118

Rosin .....................................................................123

Stilbene, derivatives of 4,4-bis(triazin-2-ylamino)- .................................125

Thiols .....................................................................128

Substituted Triazines .........................................................131

Triarylmethane Pigments/Dyes

with Non-solubilizing Groups ...............................132

Vinyl Esters ................................................................137

Vinyl Sulfones ..............................................................139

Soluble complexes of Zinc .....................................................143

Zirconium Compounds .......................................................144

vi 
Category: Acid Chlorides Environmental Toxicity 

Definition. This category includes carbonyl chlorides (R-C[=O]Cl) and sulfochlorides (RS[=O]Cl) where R may be either aliphatic or aromatic. Toxicity is limited by the fact that this 

class of compounds hydrolyzes and also, probably, if the octanol/water partition coefficient 

(Kow) is above a log Kow value of 8. It has been assumed that these compounds need to be 

absorbed to be toxic, therefore, compounds with MWs > 1000 will probably be excluded in the 

future once this assumption is confirmed with toxicity information. However, toxicity 

information is needed to confirm this assumption. 

Hazard Concerns. Acute toxicity for three members of this category are available and all have 

been shown to be moderately toxic to aquatic organisms (i.e., acute toxicity values between 1 

and 100 mg/L): benzoyl chloride, fish 96-h LC50 = 35.0 mg/L, an aromatic dicarboxyl 

dichloride, fish 96-h LC50 = 6.2 mg/L, and benzene sulfochloride, fish 48-h LC50 = 3.0 mg/L. 

All of these tests have been done with the static method using nominal concentrations. It is 

unclear just how acid chlorides are toxic to aquatic organisms. It is known that acid chlorides 

hydrolyze to the carboxylic/sulfonic acid and HCl. It is not known if the toxic effect is the result 

of (1) absorption of the acid chloride and hydrolysis within the membrane, or (2) the HCl 

produced from the hydrolysis. It is known that the carboxylic/sulfonic-acid hydrolysis products 

are of low toxicity. 

Boundaries. There are no known lower boundaries. The upper boundaries will be based on Kow 

and MW when enough information is obtained. In general, when the log Kow value is < 8, the 

environmental base set of tests will be requested for aquatic releases and the terrestrial base set 

of tests will be recommended for terrestrial exposures. When the log Kow is > 8, testing will be 

requested until enough information is obtained to determine whether these compounds will have 

no toxic effects at saturation. Generally, members of this category will have MWs of less than 

1000 but testing of members with a MW > 1000 may be requested to confirm whether acid 

chlorides have to be absorbed to be toxic. 

General Testing Strategy. The testing strategy for acid chlorides will consist of two steps. (1) 

Hydrolysis as a function of pH at 25 °C (40 CFR 796.3500) will be recommended. Depending 

on the outcome of this environmental fate testing and reassessment, (2) the aquatic base set of 

environmental toxicity tests will be recommended for aquatic exposures with the fish acute 

toxicity test done once or twice. 

Chronic toxicity testing for aquatic organisms include: the fish early life state toxicity 

test, the daphnid partial life cycle toxicity test and the algal toxicity test. 

The terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test, the 

earthworm acute toxicity test and the soil microbial community bioassay) will be recommended 

for terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant 

whole life cycle test, the plant uptake test, and the soil microbial community bioassay. 

October, 1990 

1 
Category: Acid Dyes and Amphoteric Dyes Environmental Toxicity 

Definition. Organic dyes are divided into four classes depending on the type of electronic 

charge of the dye: nonionic (neutral dyes); anionic (negative charge or acid dyes); cationic 

(positive charge) dyes; and amphoteric (mixture of positive and negative charges on same 

molecule) dyes. Nonionic or neutral dyes are assessed as neutral organic chemicals for which 

there is a separate category description, and cationic dyes also have a separate category 

description. Amphoteric dyes are assessed either as cationic or anionic dyes depending on 

dominant net charge. 

Hazard Concerns. Analysis of over 200 acid dyes (Auer et al. 1990, Nabholz 1990, Sigman et 

al. 1983, Tonogai et al. 1979, Little and Lamb 1972, ADMI 1974) have indicated that some 

monoacid and diacid dyes can show moderate to high toxicity (i.e., acute values < 100 mg/L and 

< 1 mg/L) to fish and aquatic organisms. Dyes with three or more acid groups showed low 

toxicity (i.e., acute values > 100 mg/L) towards fish and invertebrates. Some metal chelated 

dyes, i.e., Al, Co, Cr, Fe, have shown moderate toxicity towards fish and daphnids and the 

toxicity has not been explained by the residual free (un-chelated) metal ion in the dye product. 

All acid dyes showed moderate toxicity towards green algae. Analysis of available data (Auer et 

al. 1990, Nabholz 1990) has suggested that effects to algae were not the result of direct toxicity 

but represented an indirect effect due to shading. Senior regulatory decision-makers in OPPT 

(then OTS) decided in 1988 that the risk to algae from indirect (shading) toxicity was not an 

unreasonable risk for two main reasons: (1) algae grew quickly as soon as the dye was diluted, 

and (2) the release of colored effluents in the U. S. generally results in immediate complaints by 

citizens to their local authorities, e.g., county and state governments. The rapid response by the 

public generally results in quick regulatory action by local officials. 

Since there is no SAR for acid dyes (Auer et al. 1990), hazard profiles for monoacid dyes 

are developed using measured data or data for the nearest analog(s). 

Boundaries. Acids dyes must have some water solubility and molecular weights generally need 

to be near or below 1000. 

General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. Because of the above boundary conditions, and the need to assess human 

exposure as well as environmental toxicity, if there is insufficient knowledge about the water 

solubility of the dye, then it should be measured (40 CFR §796.1860). The fish and daphnid 

acute toxicity tests from the aquatic base set of environmental toxicity tests will be 

recommended for aquatic exposures. The acute toxicity tests for fish (40 CFR §797.1400) and 

daphnids (40 CFR §797.1300) will be done using the flow-through method with measured 

concentrations, and effective concentrations will be based on 100% active ingredients (AI) and 

mean measured concentrations. 

If there is no significant risk from the PMN after the results of the fish and daphnid acute 

2 
toxicity tests have been integrated into the risk assessment, then no further testing is 

recommended. However, if there is a significant risk, then go to Tier 2. 

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, go to Tier 4. 

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40 CFR 796.3765 (b)(2) and (c)(2)], expose to 

sunlight for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive 

species from environmental base set. 

Tier 4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR 797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; and statistical 

analysis of effective concentrations at days 7, 14, 21, and 28. 

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21. 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation

Modified Sturm Test

Closed Bottle Test

Modified OECD Screening Test

Modified MITI Test (I)

Modified AFNOR Test

II. Release to Terrestrial Ecosystems: 

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

The terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test, 

the earthworm toxicity test and the soil microbial community bioassay) will be recommended for 

terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant whole 

life cycle test, the plant uptake test, and the soil microbial community bioassay. 

3 
References. 

American Dye Manufacturers Institute, Inc. (ADMI), 1974, "Dyes and the Environment: 

Reports on Selected Dyes and Their Effects," Vol. II, ADMI, New York. 

Auer, C.M., Nabholz, J.V. and Baetcke, K.P., 1990, "Mode of Action and the Assessment of 

Chemical Hazards in the Presence of Limited Data: Use of Structure-Activity 

Relationships (SAR) under TSCA, Section 5," Environmental Health Perspectives, Vol. 

87, pp. 183-197. 

Little, L.W. and Lamb J.C., III, 1972, "Acute Toxicity of 46 Selected Dyes to the Fathead 

Minnow, Pimephales promelas,"Final Report to the American Dye Manufacturers 

Institute,Inc., UNC Wastewater Research Center, Department of Environmental Sciences 

and Engineering, School of Public Health, University of North Carolina, Chapel Hill, 

NC. 

Nabholz, J.V., 1990, "The OTS PMN ECOTOX Data Base: a Confidential Business Information 

(CBI) Collection of Environmental Toxicity Data from New Chemical Submissions 

Under Sec. 5," Unpublished, Environmental EffectsBranch, Health and Environmental 

Review Division (TS-796),U. S. Environmental Protection Agency, Washington, DC. 

Sigman, C.C., Helms, C.T., Papa, P.A., Atkinson, D.L., Doeltz, M.K. and Winship-Ball, A., Jan. 

1983, "Anthraquinone Dyes and Related Chemicals: Review and Assessment of 

Potential Environmental and Health Aspects," Final Report to the Dyes Environmental 

and Toxicology Organization, Inc., SRI International, Menlo Park, CA. 

Tonogai, Y., Ito, Y., Iwaida, M., Tati, M., Ose, Y. and Sato, T., 1979, "Studies on the Toxicity of 

Coal-Tar Dyes. II. Examination of the Biological Reaction of Coal-Tar Dyes to Vital 

Body," The Journal of Toxicological Sciences, Vol. 4, pp. 211-219. 

July, 1991; revised June, 1994 

4 
Category: Acrylamides Human Health and Environmental Toxicity 

Definition. Any new chemical with the following structure is considered to be a member of the 

category: 

A typical acrylamide in the new chemical program is used as a monomer and has a 

molecular weight of <500. The acrylamides of greatest concern are those with a labile 

substituent, e.g., methylol acrylamides, that may release acrylamide per se under metabolic 

conditions. For toxicity to aquatic organisms, there is a concern for all substituted acrylamides 

with molecular weights of <1000 and log Kow of <8.0. 

Hazard Concerns. Based on analogy to acrylamide per se, members of the class are considered 

potential carcinogens, heritable mutagens, reproductive and developmental toxicants, and toxic 

to aquatic organisms. Acrylamides are also potential neurotoxins based on data for a number of 

low molecular weight acrylamides. 

Boundaries. Structures with an acrylamide equivalent weight of >5,000 are presumed not to 

pose a hazard under any conditions. Typically, concerns are confined to those species with 

molecular weights <1,000 whenever inhalation (or environmental) exposure is expected, and to 

species <500 when dermal, but not inhalation, exposure to humans is expected. 

Occupational Exposure Controls. Because acrylamides are expected to be absorbed via the 

dermal route, glove permeation testing conducted in accordance with standard ASTM testing 

protocols may be required, depending upon estimated workplace exposures and the hazard 

identified for the particular acrylamide submitted as a PMN. 

5 
General Testing Strategy. 

Tier 1. To properly assess human and environmental toxicity or exposure, certain physicalchemical or environmental fate properties need to be measured: 

water solubility (40 CFR §796.1860)

Kow (40 CFR §796.1570 or 40 CFR §796.1550)

vapor pressure (40 CFR §796.1950)

melting point-melting range (OECD 102 or OPPTS 830.7200)

Aerobic biodegradability can be determined using one of the following test guidelines,

listed in approximate order of preference: 

Aerobic aquatic biodegradation

Modified Sturm test

Closed bottle test

Modified OECD screening test

Modified MITI test (I)

Modified AFNOR test

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

The physical state and electronic charge of the PMN substance should also be reported. 

Tier 2. EPA considers the following tests to be the most appropriate for acrylamides found to 

pose an unreasonable risk to human health: 

- 90-day subchronic toxicity (40 CFR §798.2650) with functional observational battery 

(40 CFR §798.6050) and neuropathology (40 CFR §798.6400). 

- A rodent dominant lethal assay (40 CFR §798.5450). If positive, a rodent heritable 

translocation test (40 CFR §798.5460) would be the appropriate followup test. 

- A 2-year carcinogenicity test (40 CFR §798.3300) in rats and mice. 

To address environmental toxicity concerns, the following testing is recommended, for 

acrylamides with log Kow <5: acute aquatic toxicity testing in algae, daphnid, and fish. The 

acute toxicity tests for fish (40 CFR 797.1400) and daphnids (40 CFR 797.1300) will be done 

using the flow-through method with measured concentrations; effective concentrations will be 

based on 100% active ingredients (AI) and mean measured concentrations; measured TOC of 

dilution water in the control <2 mg TOC/L; the highest treatment concentration on a mean 

measured-basis should equal the aqueous solubility limit; and solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN beyond its aqueous solubility limit. 

The algal toxicity testing (40 CFR 797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

6 
96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; and the highest 

treatment concentration on a mean measured-basis equal to the aqueous solubility limit. Solvent 

can be used to assist the PMN substance to reach its aqueous solubility limit quicker, but cannot 

be used to artificially enhance the water solubility of the PMN substance beyond its aqueous 

solubility limit. 

For acrylamides with log Kow >5 and <8, aquatic toxicity testing should be for chronic 

effects only: (1) fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing with 

rainbow trout (40 CFR 797.1600), with flow-through methods; measured concentrations; 

effective concentrations based on 100% active ingredients (AI) and mean measured 

concentrations; and statistical analysis of effective concentrations at days 30, 45, 60, 75, and 90; 

(2) daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; measured 

concentrations; effective concentrations based on 100% active ingredients (AI) and mean 

measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 21; 

and (3) algal toxicity testing (40 CFR 797.1050), with static methods; measured concentrations; 

effective concentrations based on 100% active ingredients (AI) and mean measured 

concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 96 hours; test 

medium with at least 0.300 mg/L EDTA as a final concentration; and the highest treatment 

concentration on a mean measured-basis equal to the aqueous solubility limit. Solvent can be 

used to assist the PMN substance to reach its aqueous solubility limit quicker, but cannot be used 

to artificially enhance the water solubility of the PMN substance beyond its aqueous solubility 

limit. 

November 1990; revised July 1993; revised October 1995 

7 
Category: Acrylates/Methacrylates Environmental Toxicity 

(Human Health, case-by-case) 

Definition. Any molecular structure containing one or more of the following reactive groups is 

considered to be a member of the class: 

O


5

- acrylate, CH2=CH-C-O-


O


5

- methacrylate, 	CH2=C-C-O­


|


CH3


Hazard Concerns. 

Human Health: As a result of testing conducted under an agreement between the Agency and 

the Specialty Acrylates and Methacrylates (SAM) Panel of the Chemical Manufacturers 

Association (CMA), EPA no longer controls new chemical acrylates or methacrylates as a 

category based on health concerns. However, if a new acrylate is structurally similar to a 

substance for which EPA has positive toxicity data, EPA may regulate that substance under 

TSCA section 5(e) based on its potential unreasonable risk. This will be done on a case-by-case 

basis and is expected to effectively eliminate most regulation of acrylates, especially higher 

molecular weight and polymeric substances. Despite the fact that EPA no longer expects to 

make a potential unreasonable risk to human health finding for many of the new acrylates, EPA 

still recommends the use of engineering controls or personal protective equipment to reduce 

exposures in the workplace in recognition of their potential as irritants and sensitizers. 

Environmental Toxicity: The ecotoxicity of acrylates and methacrylates is a function of the 

octanol-water partition coefficient. They exhibit simple narcosis at log P's >5, but display excess 

toxicity at lower log P's. The toxicity of acrylates and methacrylates can be predicted by a 

QSAR (quantitative structure-activity relationship), although there are some members of the 

class such as allyl methacrylate that are significantly more toxic than predicted by the QSAR. 

Boundaries. Typically, environmental toxicity concerns are confined to those species with 

molecular weights <1,000. Acute and chronic toxicity is possible at log P’s <5, and chronic 

toxicity is possible at log P’s <8. 

General Testing Strategy 

Tier 1. To properly assess environmental toxicity or exposure, certain physical-chemical or 

environmental fate properties need to be measured: 

8 
water solubility (40 CFR §796.1860)

log Kow (40 CFR §796.1570 or 40 CFR §796.1550)

vapor pressure (40 CFR §796.1950)

melting point-melting range (OECD 102 or OPPTS 830.7200)

aquatic biodegradation (40 CFR §796.3100).

The physical state and electronic charge of the PMN substance should also be reported. 

Tier 2. To address environmental toxicity concerns, the following testing is recommended: acute 

aquatic toxicity testing in algae, daphnid, and fish (all tests using measured concentrations; 

algae: static method, daphnid and fish: flow-through method). 

September, 1988; Revised July, 1993 and January, 1997. 

9 
Category: Aldehydes Environmental Toxicity 

Aldehydes are a class of organic compounds characterized by the functional group RC(=O)-H. Aldehydes are ionizable in water and exhibit excess aquatic toxicity in addition to 

narcosis. Polyaldehydes are more toxic than monoaldehydes to aquatic organisms and 

acrylic/vinyl/allylic aldehydes, e.g., acrolein, are more toxic than polyaldehydes. 

Vinyl/allylic/acrylic aldehydes are a class of organic compounds characterized by both the 

aldehyde, R-C(=O)-H, and vinyl, H2C=C-R, or allylic, R-C=C-R, functional groups. Allylic and 

vinyl aldehydes, e.g., acrolein, C=CC(=O), exhibit excess toxicity. 

It is assumed that aldehydes need to be absorbed to be toxic, therefore, aldehydes with 

MW >1000 will be excluded from this category. Acute toxicity for aldehydes is known to be 

limited by the octanol/water partition coefficient (Kow). Above a log Kow value of >6.0, 

aldehydes show no effects at saturation during 96-h exposures to fish. Aldehydes which are 

solids at room temperature may show no toxicity at saturation at lower Kow values depending on 

the melting point, i.e., the higher the melting point at a given Kow, the greater the likelihood that 

no toxicity will be observed at saturation. For solids, the no effects at saturation has to be 

determined on a case-by-case basis. There are no measured upper Kow limits for chronic toxicity 

at this time, but it may not be much above a log Kow = 8. Future testing will determine Kow 

limits. 

Hazard Concerns: The toxicity for aldehydes has been determined through SAR Analysis: 

SARs for monoaldehydes: 

log fish 96-h LC50 (moles/L) = -0.449 log Kow -3.314 

where n=54, R2

=0.53, CLOGP<6, MW<1000; 

log daphnid 48-h LC50 (millimoles/L) = -0.059 -0.608 log Kow 

where n=5, R2=1.0, CLOGP<6, MW<1000; 

log green algal 96-h EC50 (mmol/L) = 0.994 -0.812 log Kow (CLOGP) 

where n=2, R2=1.0, CLOGP<6.4, MW<1000; 

log fish ChV (millimoles/L) = -0.810 -0.680 log Kow (CLOGP) 

where n=3, R2=0.97, CLOGP<8, MW<1000; 

log daphnid ChV (millimoles/L) = -1.090 -0.576 log Kow (CLOGP) 

where n=2, R2=1.0, CLOGP<8, MW<1000; and 

log algal ChV (mmol/L) = 0.053 -0.644 log Kow (CLOGP) 

where n=5, R2

=0.99, CLOGP<8, MW<1000. 

SARs for polyaldehydes: 

10 
log fish 96-h LC50 (millimoles/L) = -1.176 -0.371 log Kow (CLOGP) 

where n=2, R2

=1.0, CLOGP<6, MW<1000; 

log fish 96-h LC50 (millimoles/L) = -1.021 -0.396 log Kow (SRC) 

where n=2, R2

=1.0, SRC<6, MW<1000; 

log daphnid 48-h LC50 (mmol/L) = -1.059 -0.440 log Kow (CLOGP) 

where n=2, R2=1.0, CLOGP<6, MW<1000; 

log daphnid 48-h LC50 (mmol/L) = -0.875 -0.471 log Kow (SRC) 

where n=2, R2=1.0, SRC<6, MW<1000; 

log green algal 96-h EC50 (mmol/L)= -1.772 -0.364 log Kow (CLOGP) 

where n=3, R2=0.99, CLOGP<6.4, MW<1000; 

log green algal 96-h EC50 (mmol/L)= -1.620 -0.388 log Kow (SRC) 

where n=3, R2

=0.99, CLOGP<6.4, MW<1000; 

log fish ChV (millimoles/L) = -2.298 -0.488 log Kow (CLOGP) 

where n=2, R2

=1.0, CLOGP<8, MW<1000; 

log fish ChV (millimoles/L) = -2.092 -0.513 log Kow (SRC) 

where n=2, R2=1.0, CLOGP<8, MW<1000; 

log daphnid ChV (millimoles/L) = -1.798 -0.488 log Kow (CLOGP) 

where n=2, R2=1.0, CLOGP<8, MW<1000; 

log daphnid ChV (millimoles/L) = -1.592 -0.513 log Kow (SRC) 

where n=2, R2=1.0, CLOGP<8, MW<1000; 

log algal ChV (millimoles/L) = -2.313 -0.348 log Kow (CLOGP) 

where n=2, R2

=1.0, CLOGP<8, MW<1000; and 

log algal ChV (millimoles/L) = -2.166 -0.367 log Kow (SRC) 

where n=2, R2

=1.0, CLOGP<8, MW<1000 

SARs for vinyl/allylic/acrylic aldehydes: 

log fish 96-h LC50 (mmoles/L) = -3.502 +0.017 log Kow (CLOGP) 

where n=3, R2=0.25, CLOGP<6, MW<1000; and 

log fish ChV (millimoles/L) = -4.377 -0.228 log Kow (CLOGP) 

where n=2, R2=1.0, CLOGP<8, MW<1000. 

11 
Environmental Fate: 

Boundaries: MW <1000. Log Kow

 <6.4 for toxicity to green algae as a 96-h EC50; and log Kow assumed to be <8.0 for chronic 

toxicity to aquatic organisms, but could be higher. 

<6.0 for acute toxicity to fish and aquatic invertebrates; log 

Kow

General Testing Strategy: 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (CFR §797.1400) and daphnids (CFR 

§797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; ideally, mean measured 

concentrations in the highest treatment concentration should be equal the aqueous solubility 

limit; and solvent can be used to assist the aldehyde to reach its aqueous solubility limit quicker, 

but cannot be used to artificially enhance the water solubility of the aldehyde beyond its aqueous 

solubility limit. Stock solutions in water should be adjusted to pH near 7.0. 

The algal toxicity testing (CFR §797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; ideally, mean 

measured concentrations in the highest treatment concentration should be equal the aqueous 

solubility limit; and solvent can be used to assist the aldehyde to reach its aqueous solubility 

limit quicker, but cannot be used to artificially enhance the water solubility of the aldehyde 

beyond its aqueous solubility limit. Stock solutions in water should be adjusted to pH near 7.0. 

If there is no significant risk from the aldehyde after the results of the environmental base 

set have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 2. Aerobic biodegradability according to any one of the following test 

guidelines (listed in order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

12 
If there is no significant risk from the aldehyde after the results of biodegradation testing 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (CFR 

§797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; ideally, mean measured concentrations in the highest treatment concentration should be 

equal the aqueous solubility limit; solvent can be used to assist the PMN to reach its aqueous 

solubility limit quicker, but cannot be used to artificially enhance the water solubility of the 

PMN beyond its aqueous solubility limit; and the 7-d ELS stage toxicity test cannot be 

substituted for the 28-d ELS toxicity test because the 7-d ELS toxicity test may underestimate 

chronic toxicity measured by the 28-d ELS toxicity test when the Chronic Values are compared. 

Stock solutions in water should be adjusted to pH near 7.0. 

Daphnid chronic toxicity testing (CFR §797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; ideally, mean measured concentrations in 

the highest treatment concentration should be equal the aqueous solubility limit; solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit; and the 

7-d daphnid chronic toxicity test cannot be substituted for the 21-d toxicity test because the fish 

7-d ELS toxicity test may underestimate chronic toxicity measured by the fish 28-d ELS toxicity 

test when the chronic values are compared. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test, the earthworm toxicity test and the soil microbial 

community bioassay) will be recommended for terrestrial exposures. Chronic toxicity testing 

for terrestrial organisms include: the plant whole life cycle test, the plant uptake test, and the 

soil microbial community bioassay. 

July, 1996 

13 
Category: Aliphatic Amines Environmental Toxicity 

This category includes primary amines, secondary amines and tertiary amines; or monoalkyl 

amines, dialkly amines and trialkyl amines, respectively. This group includes alkanes, alkenes 

and alkynes; substitutions on carbon (alkyl) chains may include but not be limited to halogens 

and hydroxyls; insertions in alkyl chain may include but not be limited to ethoxys, propoxys, 

ethers, sulfides, disulfides and polysulfides; amine oxides are also included in this category; 

fatty polyamines (e.g., diamines, triamines, tetraamines, pentamines, etc) are also included; 

amines may either be un-ionized (free) or ionized; and strong ion pairs may also be included. 

Hazard Concerns: Members of this category can be highly toxic to all groups of freshwater 

organisms (i.e., fish, aquatic invertebrates and green algae). Toxicity is related to the length of 

the hydrophobic carbon chains: the longer (or greater the number of carbons) the chain the more 

toxic to aquatic organisms when the number of amines is constant; and the greater the number of 

amines, the greater the toxicity given a constant carbon chain length. Small aliphatic amines are 

more toxic to algae than fish and invertebrates; higher molecular weight amines are equally 

toxic to all aquatic organisms. Small aliphatic amines which are un-ionized are more toxic to 

fish than when they are ionized; toxicity to algae appears to be unaffected by ionization. Strong 

ion pairs are generally much less toxic to fish and invertebrates because of solubility limitations, 

but remain highly toxic to green algae. The toxicity of each amine will be predicted using 

structure-activity relationships (SARs) and analogs contained in a generic standard 

environmental hazard review for aliphatic amines. 

Boundaries: There are no lower boundaries and the upper boundary is unknown at this time. It 

is known that a C13-NH3 Cl is still toxic to fish at less than 1 mg/L. An upper boundary for 

carbon chain length will probably be about 20 carbons but more information is needed at this 

time. Generally, members of this category will have molecular weights less than 1000. 

14 
General Testing Strategy 

Tier 1. The base set of environmental toxicity tests in clean dilution water and two fish 

acute toxicity tests done in the presence of humic acid (i.e., TOC) will be recommended. These 

test will be done under static methods with nominal concentrations. Smaller amines (e.g., Schiff 

bases) are expected to demonstrate less mitigation by humic acid (larger log P, greater 

mitigation; increase log P correlates to increased MW). If hydrolysis 1/2 life is less than one 

hour, test the hydrolysis product; if it is greater than one hour, test parent material. 

Tier 2. If TOC significantly reduces the toxicity to water column species, then toxicity 

testing for toxicity to benthic organisms (i.e., organisms that ingest sediment) will be 

recommended; however, if TOC does not significantly reduce the toxicity to water column 

species, then chronic toxicity with fish and aquatic invertebrates will be recommended as well as 

aerobic biodegradation testing. 

Aerobic biodegradability can be determined using one of the following test guidelines, 

listed in approximate order of preference: 

Aerobic aquatic biodegradation

Modified Sturm test

Closed bottle test

Modified OECD screening test

Modified MITI test (I)

Modified AFNOR test

September 1988; revised November 1995. 

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

15 
Category: Alkoxysilanes Human Health 

Environmental Toxicity 

Definition. Any molecular structure containing one or more of the following reactive groups is 

considered to be a member of the category. 

| | 

-C-O-Si­

| | 

The "typical" new chemical of concern is a polymer with a substantial fraction of species with 

molecular weights <1000 and pendant trimethoxy- or triethoxysilane groups. 

Hazard Concerns. 

Health - Concern for lung toxicity from inhalation of vapors or aerosols is based on data 

for a number of low-molecular-weight alkoxysilanes. Trimethoxysilane (TMS) is clearly the 

most toxic member of the class causing irreversible lung effects at low doses, but the Agency 

does not consider it appropriate to use TMS as a regulatory benchmark for all alkoxysilanes. 

For trimethoxysilane monomers and polymers with a low trimethoxysilyl equivalent 

weight, a NOAEL of 10 ppm (about 11 mg/kg/day) based on a 90-day study with 

vinyltrimethoxysilane in monkeys is deemed an appropriate generic benchmark. 

Alkoxysilanes in which the alkyl substituent is not a methyl group do not appear to be as 

toxic as methoxysilanes. The New Chemicals Program currently uses a generic benchmark 

NOAEL of 75 mg/kg/day, based on a 90-day inhalation study with tri(isopropenoxy)silane, for 

alkoxysilanes other than methoxysilanes. 

Ecotoxicity - Alkoxysilanes are highly toxic to algae and moderately toxic to aquatic 

invertebrates. For example, the daphnid 48-hr LC50 for dimethyldiethoxysilane is 1.25 mg/L, 

and the 15-day algal EC95's for vinyltriethoxysilane, tetraethoxy-silane, and 

trifluoropropenyl(methyl)diethoxysilane are all approximately 10 :g/L. 

Boundaries. Methoxy- and ethoxysilanes are presumed not to pose a hazard under any 

conditions if the equivalent weight is $5,000 and no more than 25% of species have molecular 

weights less than 1,000 and no more than 10% of species have molecular weights less than 500. 

For alkoxysilanes with alkyl substituents larger than propyl groups, the equivalent weight cutoff 

is 1,000. The degree of concern depends on the relative abundance of lower molecular weight 

species, but there is no molecular weight threshold above which there would be no concern. 

To better define the boundaries of the category, EPA seeks testing on a limited number of 

alkoxysilanes that focuses on (1) the relationship between molecular weight (or alkoxysilyl 

equivalent weight) and inhalation toxicity and (2) the importance of increasing alkoxy chain 

length in limiting toxicity. 

16 
General Testing Strategy 

The Agency recommends the following testing as appropriate to address health and 

environmental toxicity concerns for this category: 

1. 90-day subchronic test in rodents by the inhalation route (40 CFR 798.2650). 

2. Hydrolysis testing (40 CFR 796.3500). If t1/2 is less than one hour, base set ecotoxicity 

testing (see "3," below) is conducted with the hydrolysis products only. If t1/2 is greater than one 

hour, base set ecotoxicity testing is conducted with the parent material; the PMN submitter has 

the option of also testing with the hydrolysis products. 

3. Base-set ecotoxicity testing to include fish (40 CFR 797.1400) using the static method, 

daphnids (40 CFR 797.1300) using the static method and algae (40 CFR 797.1050) using the 

static method, all nominal concentrations. Direct dilution of the test alkoxysilane and organisms 

is added within 10 minutes. The static-renewal method is used for fish and daphnid test, plus an 

additional fish test using aged stock solution. 

Results of the acute ecotoxicity testing may trigger chronic fish (40 CFR 797.1600) and 

daphnid (40 CFR 797.1350) testing. 

4. Physical-chemical or environmental fate testing including, as appropriate, melting point 

(40 CFR 796.1300) or boiling point (40 CFR 796.1220), water solubility (40 CFR 796.1840 or 

796.1860), log Kow (40 CFR 796.1550, 796.1570 or 796.1720), vapor pressure (40 CFR 

796.1950), direct photolysis and indirect photolysis (40 CFR 796.3765). Need for water 

solubility, log Kow, and photolysis testing determined by outcome of above hydrolysis testing. 

September, 1988; revised June, 1994 

17 
Category: Aluminum Compounds 

Risk Management Statement. Greatest concern is for soluble forms of aluminum (Al). If 

water solubility is greater than 1 part per billion (1 ppb), the Agency will prohibit releases of the 

PMN substance to water pending the submission of environmental toxicity testing. 

Definition. This category includes inorganic salts of Al, complexes between Al and organic 

acids or chelates of Al by polyanionic monomers, and organoAl compounds, i.e., Al covalentlybonded with carbon. For example, some inorganic Al salts include: Al hydroxide, Al chloride, 

Al fluoride, Al nitrate, Al phosphate, and Al sulfate. Not included in this category are dyes 

complexed with Al (see dye categories addressed elsewhere within this “TSCA New Chemicals 

Program Chemical Categories” document). 

Hazard Concerns. Soluble salts of Al are known to be highly toxic to green algae and 

moderately toxic to fish and aquatic invertebrates at pH values between 6.5 to 9.0 and in terms of 

soluble Al in mg Al/L. Toxicity information are available for Al chloride, Al sulfate, and Na 

aluminate. The Office of Water (USEPA, 1988, EPA440/5-86-008) cited Seipt et al. (1984, 

Water Air Soil Pollut. 23:81-95) who concluded that "the simple hydroxides (Al(OH)2+ and 

Al(OH)2

+

) are regarded as the most dangerous forms while organically bound Al and polymeric 

forms are less toxic or essentially harmless." The Office of Water (USEPA, 1988) also 

concluded that solutions of Al in water approach chemical equilibrium rather slowly and that Al 

can form strong complexes with fulvic and humic acids. 

The toxicity profile for soluble Al salts, listed below, is based on (1) available measured (M) 

toxicity data, (2) mg Al/L (ppm Al), (3) pH between 6.5 and 9.0, and (4) moderate hardness 

(about 150.0 mg/L as CaCO3). 

fish (FHM) 96-h LC50 = 35.0 M pH7.3 H220

fish (RT) 96-h LC50 = 8.6 M pH7.5 H47

fish (RT) 96-h LC50 = 7.4 M pH6.6 H47

fish (RT) 96-h LC50 = 14.6 M pH7.3 H47

mean RT 96-h LC50 = 10.0 P n3

fish (BT) 96-h LC50 = 3.6 M pH6.5 H?

mean fish 96-h LC50 = 11.0 P n3 

daphnid (Cd) 48-h LC50 

daphnid (Cd) 48-h LC50 

mean Cd 48-h LC50 

daphnid (Dm) 48-h LC50 

daphnid (Dm) 48-h LC50 

mean Dm 48-h LC50 

mean daphnid 48-h LC50 

OW FW Acute WQC 

= 1.9 

= 3.7 

= 2.7 

= 3.9 

= 38.0 

= 12.0 

= 5.7 

= 1.5 

M pH7.4 H50

M pH7.7 H47

P n2

M pH7.0 H45

M pH7.1 H220

P n2

P n2

18 
---------------------------------------------------

---------------------------------------------------

green algal 96-h EC50 

green algal 96-h EC50 

mean algal 96-h EC50 

fish (FHM) ChV 

fish (FHM) ACR 

daphnid (Dm) ChV 

daphnid (Dm) ChV 

mean Dm ChV 

Dm ACR 

daphnid (Cd) ChV 

Cd ACR 

mean daphnid ChV 

mean daphnid ACR 

OW FW Chronic WQC 

algal ChV 

Biological Fate 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

0.570 M pH7.6 H15 

0.460 M pH8.2 H15 

0.510 P n2 

3.3 M pH7.7 H220 

11.0 M 

0.742 M pH8.3 H220 

0.320 M pH7.7 H45 

0.490 P n2 

24.0 M 

1.9 M pH7.2 H50 

1.4 M 

0.970 P n2 

5.9 M 

0.087 

0.100 P EC50÷4 

Fish (BT-eyed embryo) 30-d BCF (wb) = 50.0 M pH7.2 H242 

Fish (BT-fry) 30-d BCF (wb) = 136.0 M pH7.2 H242 

mean fish BCF = 93.0 P n2 

The toxicity profile for soluble inorganic complexes of Al can be predicted via MW adjustment 

of the toxicity for Al to the toxicity of the complex. 

Ca Al hydroxy phosphites [141 728-04-3]

Cax Al2(OH)2 (x+3-y)

 (HPO3)y @ mH2O with x = 2 to 12, (2x+5)÷2 >y>0, and m = 0 to 12; typical

composition = 31% Ca, 9.5% Al, & 8.0% P; solid with mp >250 °C (dec); S = 680 mg/L; pH

11.5;

Concentration (mg/L) 

Effect ----------------------------

Complex Al Notes 

fish 96-h LC50 120.0 11.0 P 

fish 96-h LC50 409.0 6.0 M 

daphnid 48-h LC50 60.0 5.7 P 

daphnid 48-h LC50 24.0 nm M 

green algal 96-h EC50 5.4 0.510 P 

fish ChV 35.0 3.3 P 

19 
---------------------------------------------------

--------------------------------------------------------------

--------------------------------------------------------------

--------------------------------------------------------------

daphnid ChV 10.0 0.970 P 

algal ChV 1.0 0.100 P 

Na Al fluoride [15 096-52-3]

sodium fluoaluminate; sodium fluoride aluminum; cryolite; kryolith; M12,2673; Na3 Al F6; 

MW210; composition: 13% Al; solid with mp 1000 °C; S = 610 mg/L with pH 6.2; used as an

insecticide since 1929;

Concentration (mg/L) 

Effect -------------------------------------------

Complex Al Notes 

fish 96-h LC50 85.0 11.0 P 

fish 96-h LC50 21.0 2.8 M 

daphnid 48-h LC50 44.0 5.7 P 

green algal 96-h EC50 3.9 0.510 P 

fish ChV 25.0 3.3 P 

daphnid ChV 7.5 0.970 P 

algal ChV 0.770 0.100 P 

The toxicity profile for chelates of Al with polyanionic monomers can be predicted via MW 

adjustment of the toxicity for Al to the toxicity of the chelate. 

The toxicity profile for organoAl compounds are developed for only the hydrolysis product(s) of 

Al. OrganoAl compounds are unstable in air and water. MethylAl and ethylAl are pyrophoric 

and dodecylAl slowly hydrolyses in water. 

Boundaries. The toxicity of Al compounds depends on the their water solubility, the 

bioavailability of Al, and their stability. The most important property determining the toxicity of 

Al compounds is water solubility. Water solubility cannot be predicted accurately and has to be 

measured. Molecular weight (MW) is only important when Al complexes are water soluble and 

stable. Stable complexes of Al with MWs > 1000 are not expected to be absorbed by aquatic 

organisms and Al is not expected to be bioavailable even if they are water soluble. Therefore, 

only unstable Al compounds with MWs < 1000 are expected to be toxic. 

General Testing Strategy 

Tier 1. Fate testing. Physical state (OPPTS 830.6303) and corresponding property, i.e., 

melting point-melting point range (OPPTS 830.7200) or boiling point-boiling point range 

(OPPTS 830.7220), water solubility (OPPTS 830.7840 or 7860), octanol/water partition 

coefficient (Kow) (OPPTS 830.7550 or 7570), and vapor pressure (OPPTS 830.7950); and/or 

20 
Acute environmental toxicity testing. The aquatic base set of environmental toxicity tests will be 

recommended for aquatic exposures: fish acute toxicity, daphnid acute toxicity, and green algal 

toxicity. The acute toxicity tests for fish (40 CFR §797.1400 or OPPTS 850.1075) and daphnids 

(40 CFR §797.1300 or OPPTS 850.1010) will be done using the static method; effective 

concentrations will be based on 100% active ingredients (ai) and nominal concentrations; the 

total organic carbon (TOC) concentration of dilution water in the control must be less than 2.0 

mg TOC/L; TOC must be measured in the control just prior to the start of the test; the highest 

treatment concentration on a nominal-basis should not exceed the aqueous solubility limit of the 

tested compound; solvent can not be used; and hardness of dilution water has to be less than 

180.0 mg/L as CaCO3. 

The algal toxicity testing (40 CFR §797.1050 or OPPTS 850.5400), should be done with 

the static method; effective concentrations based on 100% ai and nominal concentrations; 

statistical analysis of effective concentrations at 24, 48, 72, and 96 hours; test medium with no 

more than 0.300 mg/L EDTA as a final concentration; the TOC of the test/growth medium 

should be less than 2.0 mg TOC/L; TOC should be measured just prior to the start of the test; 

the highest treatment concentration on a nominal-basis should not exceed the aqueous solubility 

limit of the tested compound; and solvent can not used; . 

In addition fish-toxicity-mitigation testing (OPPTS 850.1085) with known amounts of 

humic acid (HA) added to dilution water, i.e., 20 mg HA/L and 10 mg HA/L, will be 

recommended. 

If there is no significant risk from the Al compound after the results of tier one testing set 

have been integrated into the risk assessment, then no further testing will be recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 2. Fate testing. Aerobic biodegradation, i.e., ready biodegradation (OPPTS 

835.3110) or sealed-vessel test (OPPTS 835.3120); and/or 

Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 CFR §797.1600 

or OPPTS 850.1400), with the flow-through method; effective concentrations based on 100% ai 

and mean measured concentrations of soluble Al; statistical analysis of effective concentrations 

at days 7, 14, 21, and 28; the TOC of dilution water in the control should be less than 2.0 mg 

TOC/L; TOC should be measured in the controls just prior to and during the test; the highest 

treatment concentration on a nominal-basis should not exceed the aqueous solubility limit of the 

tested compound; solvent can not be used; and hardness of dilution water has to be less than 

180.0 mg/L as CaCO3; and 

Daphnid chronic toxicity testing (40 CFR §797.1330 or OPPTS 850.1300), with the flowthrough method; effective concentrations based on 100% ai and mean measured concentrations 

of soluble Al; statistical analysis of effective concentrations at days 7, 14, and 21; the TOC of 

dilution water in the control should not exceed 2.0 mg TOC/L; TOC must be measured in the 

controls just prior to and during the test; the highest treatment concentration on a nominal-basis 

21 
should not exceed the aqueous solubility limit of the tested compound; solvent can not be used; 

and hardness of dilution water has to be less than 180.0 mg/L as CaCO3. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests will be recommended for terrestrial exposures. The terrestrial base set includes: the early 

seeding growth test (40 CFR 797.2800 or OPPTS 850.4230), the earthworm toxicity test (40 

CFR.795.150 or OPPTS 850.6200), the soil microbial community bioassay (40 CFR 797.3700 or 

OPPTS 850.5100), and the avian acute oral toxicity test (40 CFR 797.2175 or OPPTS 850.2100). 

Chronic toxicity testing for terrestrial organisms include: the plant whole life cycle test (OPPTS 

850.xxxx), the plant uptake test (40 CFR 797.2850 or OPPTS 850.4800), and the avian 

reproduction test (OPPTS 850.2300). 

Abbreviations. 

ACR10 = acute-to-chronic ratio = 10;

ai = active ingredients;

BCF = bioconcentration factor;

BT = brook trout;

Cd = Ceriodaphnia;

ChV = Chronic value;

Dm = Daphnia magna;

EC = effective concentration;

FHM = fathead minnow;

FT = flow-through method;

FW = fresh water;

H = hardness in mg CaCO3/L;

H? = hardness unknown;

LOEC = lowest-observed-effect concentration;

M = measured concentrations;

n# = sample size used in calculation of the mean;

nm = not measured;

NOEC = no-observed-effect concentration;

OW = Office of Water;

P = predicted;

RT = rainbow trout;

S = static method;

SAR = structure activity relationship;

SR24 = static renewal method with renewals every 24 h;

TOC = total organic carbon;

wb = whole body;

WQC = water quality criterion;

August, 1997 

22 
Category: Aminobenzothiazole Azo Dyes Human Health 

Environmental Toxicity 

Definition. Any disperse azo dye containing the substructure 2-aminobenzothiazole or 2-(pamino)phenylbenzothiazole, or phenyl ring-substituted derivatives of the same, is considered to 

be a member of the category. 

Hazard Concerns. There are oncogenicity/mutagenicity concerns for intact 

aminobenzothiazole azo dyes by analogy to dimethyl aminostyryl benzothiazole and Butter 

Yellow-type dyes, such as 4-ethyl-N,N-diethylaminoazobenzene. In addition, there are liver and 

thyroid concerns for reduction products by analogy to 2-aminothiazole, and neuro-toxicity 

concerns by analogy to chlorinated 2-aminobenzothiazole. Ecotoxicity concerns are generally 

chronic concerns only and are based on QSAR predictions for neutral organic compounds. 

Neutral organic compounds are an established ecotoxicity category, of which these dyes are part 

of the disperse dye subclass. 

Boundaries. The boundaries are not strictly defined. For a typical member of the category, R

= N- and/or ring substituted p-aminophenyl groups, and R2

1 

= halogens or nitro groups. 

General Testing Strategy 

The New Chemicals Program considers the following tests to be the most appropriate for 

aminobenzothiazole azo dyes found to pose an unreasonable risk: 

- In vivo mouse micronucleus assay in bone marrow by the i.p. route (40 CFR 798.5395). 

- 90-day subchronic toxicity test in rats by the oral route, with special attention to the 

thyroid and liver (40 CFR 798.2650). 

23 
- Fish early life stage test (40 CFR 797.1600). Chronic daphnid test (40 CFR 797.1350). 

Algae toxicity test (40 CFR 797.1050). 

- If the mouse micronucleus assay is positive, further characterization of the potential 

cancer risk may be recommended: 2-year cancer bioassay by the oral route in 2 species of 

rodents (40 CFR 798.3260). 

Potentially significant ecotoxicity risk, as well as human health risks, resulting from 

releases to water ONLY, may be addressed by environmental fate testing prior to the chronic 

ecotoxicity and human health testing. The results of the environmental fate testing may 

preclude the need for further testing. 

- Jar test to determine the settling rate and extent of removal of suspended solids from 

solution (draft protocol available). 

If the results of the jar test do not mitigate the health and/or ecotoxicity concerns, further 

characterization of the environmental fate of the dye may be recommended. 

- Coupled units test (40 CFR 796.3300). 

January, 1992. 

24 
Category: Anhydrides, Carboxylic Acid Human Health 

Definition. Any molecular structure containing one or more carboxylic acid anhydride groups is 

considered to be a member of the category for new chemical purposes. Members of the class 

include new carboxylic acid anhydrides as well as new oligomers, polymers, prepolymers, or 

reaction products of existing carboxylic acid anhydrides. As illustrated below, a typical new 

chemical carboxylic acid anhydride of concern is a polymer or oligomer containing a monomer 

such as maleic anhydride. 

Hazard Concerns. Carboxylic acid anhydrides are of concern for potential pulmonary 

sensitization based on data for phthalic, trimellitic, isopropylidene bis(phthalic), and sulfonyl 

bis(phthalic) anhydrides. Carboxylic acid anhydrides are also of concern for potential 

developmental or reproductive toxicity based on data for maleic, succinic, and phthalic 

anhydrides. 

Boundaries. Structures with a carboxylic acid anhydride equivalent weight of >5,000 are 

presumed not to pose a hazard under any conditions. Typically, concerns for health effects are 

confined to those species with molecular weights <1,000. 

The new chemical program has thus far been concerned only with those carboxylic acid 

anhydrides with potentially significant inhalation exposure, and has pursued developmental 

toxicity only for low molecular weight (<500) carboxylic acid anhydrides which are thought to 

have a significant potential for systemic uptake via the lung. For pulmonary sensitization, 

extensive systemic uptake may not be necessary for a biological response and we have therefore 

sought to regulate some oligomeric or polymeric carboxylic acid anhydrides only for that effect. 

General Testing Strategy 

The following tests are usually prescribed for carboxylic acid anhydrides found to pose a 

potentially unreasonable risk: 

- Pulmonary sensitization by either the method of Karol (Toxicol. Appl. Pharmacol. 

68:229-241, 1983), or an equivalent method. 

- Oral developmental toxicity study in two species (40 CFR §798.4900). 

May, 1991 

25 
Category: Anilines Environmental Toxicity 

This category includes all anilines, both monoanilines and polyanilines. It is assumed that these 

compounds need to be absorbed to be toxic, therefore, compounds with MWs > 1000 will be 

excluded from this category. Acute toxicity for anilines which are liquids at room temperature is 

known to be limited by the octanol/water partition coefficient (Kow). Above a log Kow value of 

=> 7.38, anilines show no effects at saturation during 96-h exposures (Veith and Broderius 

(1987). Anilines which are solids at room temperature may show no toxicity at saturation at 

lower Kow values depending on the melting point, i.e., the higher the melting point at a given 

Kow, the greater the likelihood that no toxicity will be observed at saturation. For solids, the no 

effects at saturation has to be determined on a case-by-case basis. There are no known Kow 

limits for chronic toxicity at this time, but it may not be much above a log Kow = 8 for liquid 

anilines. Future testing will determine this Kow limit. 

Hazard Concerns. The acute toxicity for anilines has been determined through SAR Analysis: 

fish 96-h LC50 (Veith and Broderius 1987);

fish 14-d LC50 (Deneer et al 1987);

fish 14-d LC50 (Hermens et al 1984);

daphnids 48-h LC100 (Nendza and Seydel 1988a and 1988b); and

green algal 96-h EC50 (Nendza and Seydel 1988a and 1988b).;

The neutral organic SARs can be used to predict green algal 96-h EC50. 

Aromatic diamines (i.e., two amines on one benzene) and dinitroanilines are known to be more 

toxic than predicted by these SARs. 

Members of this category exhibit toxicity ranging from low toxicity (i.e., > 100 mg/L) to high 

toxicity (i.e., < 1 mg/L) depending on their Kow, MW and substitutions (e.g., dinitroanilines).

Environmental Fate. Some recent studies have shown that certain anilines are subject to rapid 

direct and indirect photolysis under environmentally realistic conditions (Leifer 1990). 

Boundaries. There are no known lower boundaries. The upper boundaries will be based on Kow 

and MW. Acute toxicity expected with log Kow < 7.38; no effects at saturation during 96-h 

exposures when log Kow >= 7.38. Chronic toxicity has no known upper bound for log Kow, but it 

is probably near 8. MW will be < 1000. The environmental base set of tests will be requested 

for aquatic releases and the terrestrial base set of tests will be recommended for terrestrial 

exposures. When the log Kow is >= 7.38, chronic toxicity testing with fish and daphnids will be 

recommended. 

26 
General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (40 CFR 797.1400) and daphnids (40 CFR 

797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; the highest treatment 

concentration on a nominal-basis should equal the aqueous solubility limit; and solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

The algal toxicity testing (40 CFR 797.1050), should be done with static methods; 

measured concentrations.; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis equal to the aqueous solubility limit; and solvent can 

be used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

If there is no significant risk from the PMN after the results of the environmental base set 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 2. 

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, go to Tier 4. 

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40.796.3765 (b)(2) and (c)(2)], expose to sunlight 

for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive species 

from environmental base set. For example, the most sensitive species from the environmental 

base set has an EC50 value = 2.0 mg PMN/L (based on 100% active ingredients [AI]), therefore, 

prepare a 5.0 mg PMN per liter stock solution based on 100% AI using the standard humiccontaining solution. This stock solution is exposed to sunlight for at least 6 half-lives to ensure 

that all of the PMN has been photolyzed, and then this stock solution is used to retest the most 

sensitive aquatic species to determine if the photolysis products of the PMN are more or less 

toxic that the PMN. 

27 
Tier 4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR 797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; the highest treatment concentration on a nominal-basis should be set at the aqueous 

solubility limit; solvent can be used to assist the PMN to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the PMN beyond its 

aqueous solubility limit; and the 7-d ELS stage toxicity test cannot be substituted for the 28-d 

ELS toxicity test because Van Leeuwen et al (1990) have demonstrated that the 7-d ELS toxicity 

test underestimated the chronic toxicity of anilines measured by the 28-d ELS toxicity test by 

>5.3 times when the NOECs were compared (see Table VII in Van Leeuwen); 

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; the highest treatment concentration on a 

nominal-basis should be set at the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN beyond its aqueous solubility limit; and the 7-d daphnid chronic 

toxicity test cannot be substituted for the 21-d toxicity test because Van Leeuwen et al (1990) 

have demonstrated that the fish 7-d ELS toxicity test underestimated the chronic toxicity of 

anilines measured by the fish 28-d ELS toxicity test by >5.3 times when the NOECs were 

compared (see Table VII in Van Leeuwen). 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test, the earthworm toxicity test and the soil microbial 

community bioassay) will be recommended for terrestrial exposures. Chronic toxicity testing 

for terrestrial organisms include: the plant whole life cycle test, the plant uptake test, and the 

soil microbial community bioassay. 

28 
References. 

Deneer JW, Sinnige TL, Seinen W and Hermens JLM. 1987. Quantitative structure-activity 

relationships for the toxicity and bioconcentration factor of nitrobenzene derivatives towards the 

guppy (Poecilia reticulata). Aquatic Toxicology 10:115-129. 

Hermens J, Leeuwangh P, and Musch A. 1984. Quantitative structure-activity relationships and 

mixture toxicity studies of chloro- and alkylanilines at an acute lethal toxicity level to the guppy, 

Poecilia reticulata. Ecotoxicology and Environmental Safety 8:388-394. 

Leifer A. 1990 (14 Dec). Review of Section 5 test data for o-phenylenediamine, mphenyldiamine, and p-phenylenediamine. Memorandum. Washington, DC: Exposure 

Assessment Branch, Exposure Evaluation Division (TS-798), Office of Toxic Substances, United 

Stated Environmental Protection Agency, 401 M St, SW, 20460-0001. 

Nendza M and Seydel JK. 1988a. Multivariate data analysis of various biological test systems 

used for the quantification of ecotoxic compounds. Quantitative Structure-Activity 

Relationships 7:165-174. 

Nendza M and Seydel JK. 1988b. Quantitative structure-activity relationships for 

ecotoxicologically relevant biotest systems and chemicals. Chemosphere 17:1585-1602. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

Veith GD and Broderius SJ. 1987. Structure-toxicity relationships for industrial chemicals 

causing type (II) narcosis syndrome. In Kaiser KLE (ed), QSAR In Environmental Toxicology -

II, p 385-391. Reidel Publishing Company. 

May, 1991 

29 
Subcategory of Anilines: Dianilines Human Health 

Environmental Toxicity 

Definition. A PMN must have the following minimum structural requirements to be considered 

a member of this category: 

-it must have at least two phenyl rings with a bridging carbon, oxygen, nitrogen, or sulfur 

-each terminal phenyl ring must have a primary amino group (or a group that can be 

readily metabolized to a primary amino group) either meta- or para- to the bridging atom 

Compounds with one or more additional phenyl ring(s), with or without ring substituents, and 

one or more bridging atoms are also included in the category. 

Minimum Structure for Dianiline Category 

The compounds of greatest concern are those having X = C, N, or O and n = 0 or 1. 

Hazard Concerns: Members of the class are considered to be potential carcinogens and 

mutagens by analogy to 4,4'-methylendianiline, 4,4'-methylene bis(o-toluidine), and 4,4'-

oxydianiline. Class members are potential retinotoxic agents by analogy to 4,4'-

methylenedianiline, 4,4'-oxydianiline, and the diaminodiphenyl alkane drugs and are also 

potential reproductive and systemic toxicants by analogy to 4,4'-methylenedianiline. 

30 
General Testing Strategy 

The New Chemicals Program has considered the following toxicity tests to be the most 

appropriate for dianilines found to pose an unreasonable risk: 

I. Exposure to Humans 

- rat acute oral retinopathy screening study (protocol to be approved by EPA) 

- pigmented rat 90-day subchronic toxicity study by the oral (40 CFR 798.2650) or 

inhalation (40 CFR 798.2450) route to include histopathological examination of the eyes 

and reproductive organs (eyes to be examined by both light and electron microscopy) 

- 2-year carcinogenicity bioassay (40 CFR 798.3300) in rats and mice. 

In the 90-day subchronic toxicity study, the company may opt to carry a group of animals 

at each dose level for a 90-day recovery period to determine whether potential retinopathy is 

reversible. 

For some compounds in this class, short-term mutagenicity testing may be appropriate. 

When appropriate, specific testing will be determined by EPA mutagenicity assessors on a case 

by case basis by referral to "short question." 

Where the general population is at a significant risk from drinking water exposure (via 

surface water releases) to PMN chemicals of this class, the following fate testing may be 

appropriate: 

-direct and indirect photolysis 40 CFR 796.3765 and 796.3700 

-aerobic aquatic biodegradation 40 CFR 796.3100 

-see aniline category description for details 

Results of the above fate tests may mitigate concern for drinking water exposure to PMN 

of this class. However, fate test results WILL NOT CHANGE AGENCY CONCERNS FOR 

OCCUPATIONAL EXPOSURE to PMNs of this category. 

II. Release to Aquatic Ecosystems 

Tier 1. Because of the above boundary conditions, and the need to assess human 

exposure as well as environmental toxicity, if there is insufficient knowledge about the water 

solubility of the dye, then it should be measured (40 CFR §796.1860). The fish and daphnid 

acute toxicity tests from the aquatic base set of environmental toxicity tests will be 

recommended for aquatic exposures. The acute toxicity tests for fish (40 CFR §797.1400) and 

31 
daphnids (40 CFR §797.1300) will be done using the flow-through method with measured 

concentrations, and effective concentrations will be based on 100% active ingredients (AI) and 

mean measured concentrations. 

If there is no significant risk from the PMN after the results of the fish and daphnid acute 

toxicity tests have been integrated into the risk assessment, then no further testing is 

recommended. However, if there is a significant risk, then go to Tier 2. 

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, go to Tier 4. 

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40 CFR 796.3765 (b)(2) and (c)(2)], expose to 

sunlight for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive 

species from environmental base set. 

Tier 4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR 797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; and statistical 

analysis of effective concentrations at days 7, 14, 21, and 28. 

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21. 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation

Modified Sturm Test 

Closed Bottle Test 

Modified OECD Screening Test 

Modified MITI Test (I) 

Modified AFNOR Test 

III. Release to terrestrial Ecosystems: 

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

The terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test, 

the earthworm toxicity test and the soil microbial community bioassay) will be recommended for 

terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant whole 

life cycle test, the plant uptake test, and the soil microbial community bioassay. 

32 
References 

American Dye Manufacturers Institute, Inc. (1974). "Dyes and the Environment: Reports on 

Selected Dyes and Their Effects," Vol. II, ADMI, New York. 

Auer, C.M., Nabholz, J.V. and Baetcke, K.P. (1990). "Mode of Action and the Assessment of 

Chemical Hazards in the Presence of Limited Data: Use of Structure-Activity Relationships 

(SAR) under TSCA, Section 5," Environmental Health Perspectives, Vol. 87, pp. 183-197. 

Little, L.W., and Lamb J.C., III (1972). "Acute Toxicity of 46 Selected Dyes to the Fathead 

Minnow, Pimephales promelas, "Final Report to the American Dye Manufacturers Institute, Inc., 

UNC Wastewater Research Center, Department of Environmental Sciences and Engineering, 

School of Public Health, University of North Carolina, Chapel Hill, NC. 

Nabholz, J.V. (1990). "The OTS PMN ECOTOX Data Base: a Confidential Business 

Information (CBI) Collection of Environmental Toxicity Data from New Chemical Submissions 

Under Sec. 5," Unpublished, Environmental Effects Branch, Health and Environmental Review 

Division (TS-796), U. S. Environmental Protection Agency, Washington, DC. 

Sigman, C.C., Helms, C.T., Papa, P.A., Atkinson, D.L., Doeltz, M.K., and Winship-Ball, A. (Jan. 

1983). "Anthraquinone Dyes and Related Chemicals: Review and Assessment of Potential 

Environmental and Health Aspects," Final Report to the Dyes Environmental and Toxicology 

Organization, Inc., SRI International, Menlo Park, CA. 

Tonogai, Y., Ito, Y., Iwaida, M., Tati, M., Ose, Y., and Sato, T. (1979). "Studies on the Toxicity 

of Coal-Tar Dyes. II. Examination of the Biological Reaction of Coal-Tar Dyes to Vital Body," 

The Journal of Toxicological Sciences, Vol. 4, pp. 211-219. 

August 1991; revised January 1995; revised October 1995 

33 
Category: Anionic Surfactants Environmental Toxicity 

Definition. Any molecular structure with a net negative charge and having surfactant activity is 

a member of this category. The category includes for example, alkyl sulfonates, alkyl benzene 

sulfonates, alkyl silicic acids, alkyl phosphates, alkyl carboxylic acids, or combinations of these 

anionic groups, e.g., alkyl sulfonate with carboxylic acid substitutions. 

Hazard Concerns. Anionic surfactants are toxic to a wide variety of aquatic organisms. 

Toxicity increases exponentially with increasing carbon chain length up to 16 carbons [for linear 

alkyl sulfonate (LAS) surfactants], and then decreases with additional carbons. At a chain length 

of 16 carbons, fish and daphnids are most sensitive, but at lower chain lengths green algae are 

more sensitive than fish and daphnids. There are a number of structure-activity relationships 

(SARs) to predict the toxicity of members of this category. Most are parabolic regression 

equations and others rely on nearest analog methodology. 

Boundaries. There is no molecular weight boundary. Surfactants with molecular weights > 

1000 are still toxic. Acute toxicity may be low, i.e., > 100 mg/L, if a strong cationic surfactant 

counterion and the anionic surfactant form a tight ion pair. 

Testing. To address ecotoxicity concerns, base set acute aquatic toxicity testing (green 

algae: static method, daphnid and fish: flow-through method, all measured concentrations). 

Tier 1. The acute aquatic base set of environmental toxicity tests will be recommended 

for aquatic exposures and the terrestrial base set of environmental toxicity tests (i.e., the early 

seeding growth test, the earthworm acute toxicity test and the soil microbial community 

bioassay) will be recommended for any terrestrial exposures. 

Acute fish toxicity test

Acute daphnid toxicity test

Green algae toxicity test

Early seedling growth test

Earthworm acute toxicity test

Soil microbial community bioassay

OPPTS 850.1075 

OPPTS 850.1010 

OPPTS 850.5400 

OPPTS 850.4230 

OPPTS 850.6200 

OPPTS 850.5100 

34 
Tier 2. If acute toxicity testing indicates a significant risk, then environmental fate 

testing in the form of aerobic biodegradation testing is recommended. Aerobic biodegradability 

can be determined using one of the following test guidelines, listed in approximate order of 

preference: 

CO2 evolution

Closed bottle

Modified OECD screening

Modified MITI (I)

DOC die-away

Manometric respirometry

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

Tier 3. In addition, if acute toxicity testing indicates a significant risk, then chronic 

aquatic toxicity testing with fish and aquatic invertebrates will be recommended. 

Fish early life stage test OPPTS 850.1400 

Daphnid chronic toxicity testing OPPTS 850.1300 

September 1988, revised September, 1996 

35 
Category: Azides Environmental Toxicity 

Azides are a class of chemicals consisting of both inorganic and organic compounds and 

characterized by the functional group N=N=N. Substitutions may be either metals or organic 

compounds, e.g., acetic acid and benzene. So far, only monomeric aromatic azide compounds 

have been submitted as PMNs. No aliphatic azides, e.g., alkyl azides, have been submitted as 

PMNs. Aliphatic azides may be too explosive to isolate, however, diazidoacetic acid ester is 

known to exist and has been tested in rats. 

Hazard Concerns: It is assumed that azides have to be absorbed to be toxic, therefore, azides 

with MW >1000 will be excluded from this category. Acute toxicity for monomeric azides is 

assumed to be correlated and limited by the octanol/water partition coefficient (Kow). Above a 

log Kow value of >5.0, azides are assumed to show no effects at saturation during 96-hour 

exposures to fish. Organic azides which are solids at room temperature may show no toxicity at 

saturation at lower Kow values depending on their melting point and/or their water solubility. For 

example, for organic azides, the higher the melting point at a given Kow, the greater the 

likelihood that no toxicity will be occur at saturation. For solids, no effects at saturation has to 

be determined on a case-by-case basis. There are no measured upper Kow limits for chronic 

toxicity at this time, but it may not be much above a log Kow = 8. Future testing will determine 

Kow limits. 

The aquatic toxicity of organic azides has been determined through SAR Analysis: 

log fish 96-h LC50 (millimoles/L) = -1.881 -0.124 log Kow 

where n=2, R2=1.0, LOGKOW(SRC)<5, MW<1000; 

The toxicity for inorganic azides has to be determined by integrating the toxicity of Na 

azide with the toxicity of any other inorganic element, e.g., Pb, with a MW adjustment for 

differences in toxicity between Na azide and the other inorganic element. Na azide [26628-22-8] 

has been tested by the USEPA ERL-Duluth: fathead minnow 96-h LC50 = 5.46 mg/L based on a 

flow-through method with 18 volume changes per day and nominal concentrations. The SAR for 

organic azides is based on (1) this toxicity value, (2) a calculated log Kow value of -6.3 using 

SRC's LOGKOW, and (3) no acute effects to fish at saturation assumed to occur at a log Kow 

>5.0 which is equivalent to a log fish 96-h LC50 = -2.5 in millimoles per liter. CLOGP has a 

missing fragment constant for the azide group. 

Environmental Fate: Na azide is known to hydrolyze in water to form hydrazoic acid (or 

, [7782-79-8], MW43, M12,4815). Hydrogen azide is extremely explosive 

according to Merck. In addition, azides can be transformed to nitrenes by uv light. 

hydrogen azide, NH3

Boundaries: MW <1000. Log Kow

50; and log Kow assumed to be <8.0 for chronic 

toxicity to aquatic organisms, but could be higher. 

<5.0 for acute toxicity to fish and aquatic invertebrates; log 

Kow <6.4 for toxicity to green algae as a 96-h EC

36

General Testing Strategy: 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (OPPTS 850.1075) and daphnids (OPPTS 

850.1010) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (ai) and mean measured concentrations; 

measured TOC of dilution water in the control; ideally, mean measured concentrations in the 

highest treatment concentration should be equal the aqueous solubility limit; and solvent can be 

used to assist the aldehyde to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the test chemical significantly above its aqueous 

solubility limit. 

The algal toxicity testing (OPPTS 850.5400), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (ai) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; ideally, mean 

measured concentrations in the highest treatment concentration should be equal the aqueous 

solubility limit; and solvent can be used to assist the aldehyde to reach its aqueous solubility 

limit quicker, but cannot be used to artificially enhance the water solubility of the test chemical 

significantly above its aqueous solubility limit. 

If there is no significant risk from the PMN chemical after the results of the 

environmental base set have been integrated into the risk assessment, then no further testing is 

recommended. However, if there is a significant risk, then go to Tier 2. 

Tier 2. Aerobic biodegradability according to either of the following test guidelines: 

Ready Biodegradability OPPTS 835.3110 

Sealed Vessel CO2 Production Test OPPTS 835.3120 

If there is no significant risk from the PMN chemical after the results of biodegradation 

testing have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing 

(OPPTS 850.1400), with flow-through methods; measured concentrations; effective 

concentrations based on 100% active ingredients (AI) and mean measured concentrations; 

statistical analysis of effective concentrations at days 7, 14, 21, and 28; measured TOC of 

dilution water in the control; ideally, mean measured concentrations in the highest treatment 

concentration should be equal the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN significantly above its aqueous solubility limit; and the 7-d ELS 

37

stage toxicity test cannot be substituted for the 28-d ELS toxicity test because the 7-d ELS 

toxicity test may underestimate chronic toxicity measured by the 28-d ELS toxicity test when the 

Chronic Values are compared. 

Daphnid chronic toxicity testing (OPPTS 850.1300), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; ideally, mean measured concentrations in 

the highest treatment concentration should be equal the aqueous solubility limit; solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN significantly above its aqueous solubility 

limit; and the 7-d daphnid short-term chronic toxicity test cannot be substituted for the 21-d 

toxicity test because the daphnid 7-d short-term toxicity test may underestimate chronic toxicity 

measured by the 21-d toxicity test when the chronic values are compared. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test [OPPTS 850.4230], the earthworm toxicity test [OPPTS 

850.6200], and the soil microbial community bioassay [OPPTS 850.5100]) will be recommended 

for terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant 

whole life cycle test, the plant uptake test, and the soil microbial community bioassay. 

References: 

L’Abbe, G. (1969). Decomposition and addition reactions of organic azides. Chemical Review, 

69, 345-363. 

Scriven, E.F. (Ed.). (1984). Azides and nitrenes: Reactivity and utility. pp.95-204. New York: 

Academic Press. 

September 1996 

38

Category: Benzotriazoles Environmental Toxicity 

Definition. This category includes all benzotriazoles. 

Hazard Concerns. The toxicity for benzotriazoles with -NH has been determined through SAR 

Analysis (Clements 1988). Benzotriazoles with -NH are known to be more toxic than neutral 

organic chemicals, and this excess toxicity decreases with increasing Kow. The toxicity of 

benzotriazoles with aliphatic substitutions on the nitrogen are expected to act like neutral organic 

compounds. Other substitutions on the N, e.g., -SH, have to be evaluated on a case-by-case 

basis. 

Members of this category exhibit toxicity ranging from low toxicity (i.e., > 100 mg/L) to high 

toxicity (i.e., < 1 mg/L) depending on their Kow, MW, and melting point.

Boundaries. There are no known lower boundaries. The upper boundaries will be based on 

Kow, MW, and melting point (mp). These compounds need to be absorbed to be toxic, 

therefore, compounds with MWs < 1000 are expected to cause toxicity, while compounds with 

MWs > 1000 are no expected to show toxicity at saturation. 

Acute toxicity for benzotriazoles which are liquids at room temperature is known to be limited 

by the octanol/water partition coefficient (Kow). Above a log Kow value of 5.0, benzotriazoles 

show no effects at saturation during 96-h exposures (Clements 1988). Benzotriazoles which are 

solids at room temperature may show no toxicity at saturation at lower Kow values depending on 

the melting point, i.e., the higher the melting point at a given Kow, the greater the likelihood that 

no acute toxicity will be observed at saturation. For solids, the no-effects-at-saturation point for 

acute toxicity has to be determined on a case-by-case basis. 

The Kow limit for chronic toxicity is set at a log Kow

chronic toxicity testing will determine the Kow limit. 

= 8 for liquid benzotriazoles. For solids, 

Therefore, acute toxicity is expected when log Kow =< 5.0 and MW < 1000; no effects at 

saturation during 96-h exposures are expected when log Kow > 5.0 and MW < 1000. The upper 

boundary for chronic toxicity is 8.0. Only chronic toxicity is expected when log Kow > 5.0 and < 

8.0, and MW < 1000. Whenever MW > 1000, no effects are expected at saturation because it is 

assumed that benzotriazoles have to be absorbed to be toxic. 

Aerobic biodegradation is expected to be the dominant route of transformation in the 

environment. 

39

General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (40 CFR §797.1400) and daphnids (40 CFR 

§797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; the highest treatment concentration on a nominal-basis should not exceed the 

aqueous solubility limit of the tested chemical; and solvent can be used to assist the chemical to 

reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the water 

solubility of the chemical beyond its aqueous solubility limit. 

The algal toxicity test (40 CFR §797.1050) should be done with the static method; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis should not exceed the aqueous solubility limit of the 

chemical; and solvent can be used to assist the chemical to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the chemical beyond its 

aqueous solubility limit. 

If there is no significant risk from the benzotriazole after the results of the environmental 

base set have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 2. Aerobic biodegradability according to any one of the following test guidelines 

(listed in order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

If there is no significant risk from the benzotriazole after the results of the aerobic 

biodegradation testing have been integrated into the risk assessment, then no further testing is 

recommended. However, if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR §797.1600), with flow-through methods; measured concentrations; effective 

concentrations based on 100% active ingredients (AI) and mean measured concentrations; 

statistical analysis of effective concentrations at days 7, 14, 21, and 28; the highest treatment 

concentration on a nominal-basis should not exceed the aqueous solubility limit for the chemical; 

solvent can be used to assist the chemical to reach its aqueous solubility limit quicker, but cannot 

40

be used to artificially enhance the water solubility of the chemical beyond its aqueous solubility 

limit; and the 7-d ELS stage toxicity test cannot be substituted for the 28-d ELS toxicity test 

because Van Leeuwen et al (1990) have demonstrated that the 7-d ELS toxicity test 

underestimated the chronic toxicity of anilines measured by the 28-d ELS toxicity test by >5.3 

times when the NOECs were compared (see Table VII in Van Leeuwen). Both anilines and 

benzotriazoles with -NH are more toxic than predicted based on narcosis alone, i.e., both 

benzotriazoles and anilines have excess toxicity due to a more specific mode(s) of toxic action. 

A seven day exposure may not allow enough time for this excess toxicity to be expressed either 

because of not enough exposure and/or not enough time for metabolic activation. 

Daphnid chronic toxicity testing (40 CFR §797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; the highest treatment concentration on a nominal-basis should not exceed the aqueous 

solubility limit of the chemical; solvent can be used to assist the chemical to reach its aqueous 

solubility limit quicker, but cannot be used to artificially enhance the water solubility of the 

chemical above its aqueous solubility limit; and the 7-d daphnid chronic toxicity test cannot be 

substituted for the 21-d toxicity test (Van Leeuwen et al 1990). 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test, the earthworm toxicity test, the avian acute oral toxicity 

test, and the soil microbial community bioassay) will be recommended for terrestrial exposures. 

Chronic toxicity testing for terrestrial organisms include: the plant whole life cycle test, the 

plant uptake test, the avian reproductive toxicity test, and the soil microbial community bioassay. 

In addition, the fate test for Inherent Biodegradability in soil (40 CFR §796.3400) may be 

recommended. 

References 

Clements, RG (editor). 1988. Estimating toxicity of industrial chemicals to aquatic organisms 

using structure-activity relationships. EPA-560-6-88-001. Washington, DC: Environmental 

Effects Branch, Health and Environmental Review Division, Office of Toxic Substances (TS796), United States Environmental Protection Agency. Available from the National Technical 

Information Service, Springfield, VA 22161, PB89-117592. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

March, 1992 

41

Category: Benzotriazole-hindered phenols Human Health 

Environmental Toxicity 

(see “Phenols”) 

The predominant use of members of this category is as a UV light stabilizer in coating or 

plastic formulations. 

Definition. Any molecular structure containing the following substructure is considered to be a 

member of the category. 

Note: Health effects may vary depending on the nature of the ring substituents. 

Hazard Concerns. 

I. Health 

Systemic toxicity based on 8(e) and PMN data on analogues. These data are generally consistent 

across compounds, with the following endpoints occurring in subacute, subchronic, and chronic 

oral feeding studies in rats and dogs in which doses ranged from 5 to 15,000 ppm. 

Increased organ weights (liver and kidney, with associated histopathology at higher doses); 

hematological effects (decreased hemoglobin, packed cell volume, and erythrocytes); and 

immune system effects (weight changes in thymus, spleen, lymph nodes; decreased leukocytes). 

Generally, treatment-related effects are dose-related, increasing in frequency and severity with 

increasing dose. Males appear to be more sensitive than females, and similar toxic effects occur 

in both rats and dogs. 

The lowest available NOAEL for systemic effects, from a 90-day rat study, is 5 ppm, or 0.25 

mg/kg/day. 

Reproductive toxicity - Concern is also based on 8(e) and PMN data on analogues. As with 

42

systemic toxiciy, the data are generally consistent, with the following endpoints occurring in 

subacute and subchronic oral feeding studies in rats and dogs in which doses ranged from 5 to 

15,000 ppm. 

Atrophy of the seminal vesicles, significant reduction in absolute and relative testes weight, 

significant reduction in absolute and relative prostate weight, and abnormal spermatogenesis. A 

subchronic dog study also provided evidence of female reproductive toxicity. 

Generally, treatment-related effects are dose-related, increasing in both frequency and severity 

with increasing dose. Males appear to be more sensitive than females, and similar toxic effects 

occur in both rats and dogs. 

The lowest NOAEL for reproductive toxicity, from a 90-day dog study, is 15 mg/kg/day. 

Dermal sensitization - Dermal sensitization test data were positive in 3/4 compounds tested. 

Two of the compounds showed strong sensitizing potential based on results obtained from 

maximization tests in which 70% and 90% of the treated guinea pigs became sensitized, 

respectively. 

II. Environmental - The environmental concerns for the substances described in this category 

have already been described in the Phenol category. 

Boundaries. Not enough is known about the structure-activity relationships of these compounds 

to set any boundaries on members of the category; compounds with both "small" and "large" 

substituents have shown effects, and the effects are generally consistent from compound to 

compound. 

General Testing Strategy 

I. Health 

Systemic Toxicity and Reproductive Toxicity. A 90-day gavage study in rats with special 

attention to hematology; weight and histopathology of lymphoid organs (spleen, thymus, and 

bone marrow); cellularity of the bone marrow, thymus, and spleen; and histopathology of the 

liver, kidney, heart, and all endocrine glands for which weight changes are observed. Particular 

attention should be directed toward achieving satisfactory quality from fixation and embedding 

of the testes, following the recommendations of Russell et al. [Russell LD, Ettlin RA, Sinha 

Hikim AP, Clegg ED. 1990. Histological and histopathological evaluation of the testis. Cache 

River Press, Clearwater, FL]. 

A gavage study, as opposed to an oral feeding study, is recommended because decreased 

body weight gain, final body weight, and/or food consumption have been reported in some oral 

feeding studies with analogues. 

43

If immunopathology and hematology in the 90-day study support the concern for adverse 

effects of the PMN substances on the immune system, then a further battery of tests, such as the 

NTP's Immunotoxicology Tier II Screening Panel, will be recommended. 

Dermal Sensitization. Because dermal sensitization is not routinely pursued under TSCA 

5(e) as a regulatory endpoint, testing is not recommended. A letter be sent to the PMN submitter 

expressing the Agency's belief that the compounds are likely to be dermal sensitizers and that 

protective measures should be taken for workers. 

II. Environmental toxicity 

If exposure to the aquatic environment demonstrates a potential risk, testing of the 

substances described in this category is the same as that prescribed for the Phenols category. 

June, 1993. 

44

Category: Boron Compounds Human Health 

Environmental Toxicity 

Definition. This category includes borates, organoborates, borate esters, boron hydrides, 

boranes, and boroxines. 

Human Health: 

Hazard Concerns. Reproductive toxicity (males/females), blood toxicity, and neurotoxicity. 

The Agency has an oral RfD for boron of 0.09 mg/kg/day (uncertainty factor 100) based on the 

finding of testicular atrophy and spermatogenic arrest in dogs in a 2-yr feeding study (Weir and 

Fisher 1972, as summarized in IRIS 1995). [All toxicity information presented here are 

summarized in an assessment of various aqueous cleaner chemicals prepared in 1990 for the 

Office of Air and Radiation. Reproductive toxicity information also summarized in IRIS 1995.] 

Reproductive Toxicity. The most significant effect seen in animals is reproductive toxicity (i.e., 

sterility in males and females, and testicular atrophy in males). A three-generation reproductive 

study in rats demonstrated sterility in males (lack of spermatozoa in atrophied testes) and 

females (decreased ovulation) after exposure to 58.5 mg boron/kg in the diet. NOAEL (rats) 

17.5 mg boron/kg. Sterility was also found in males (at 50 or 100 mg boron/kg) in a serial 

mating adjunct to a 60-day feeding study; NOAEL (rats) 25 mg boron/kg. 

Data from oral subchronic and chronic studies in rats, dogs, and mice also provide evidence that 

boron produces adverse effects on the male reproductive system. A statistically significant 

reduction in relative and absolute testes weights was seen in a 2-yr and a 90-day dietary study in 

male rats at 58.5 and 26.3 mg boron/kg, respectively. NOAEL’s (rats) 17.5 and 8.8 mg 

boron/kg, respectively. In male rats, dietary exposure to 50 mg/kg boron resulted in a significant 

reduction in fertility, a significant reduction in epididymal weight, and a reduction in sperm 

number after 30 days of treatment. A significant reduction in testicular weight and further 

reduction in sperm occurred after 60 days of treatment. NOAEL (rats) 25 mg boron/kg. Similar 

results were observed in several drinking water studies in rats. 

In male dogs, dietary exposure to 29.4 mg boron/kg for 2 yr resulted in severe testicular atrophy 

and spermatogenic arrest. NOAEL (dogs) 8.8 mg boron/kg. In male and female dogs, dietary 

exposure to 43.8 and 4.4 mg boron/kg for 90 days did not affect the female reproductive system, 

but produced decreased testes weights (statistically significant at 43.8 mg boron/kg). NOAEL 

(dogs) 0.4 mg boron/kg. In male mice, dietary exposure to 131 mg boron/kg for 103 wk (only 

dose tested) caused an increased incidence of testicular atrophy and interstitial hyperplasia. 

Blood Toxicity. In a chronic feeding study in rats, packed cell volume and hemoglobin levels 

were significantly decreased in males and females at 58.5 mg boron/kg. NOAEL (rats) 17.5 mg 

boron/kg. In a subchronic drinking water study in rats, a significant decrease in plasma 

triglyceride levels was noted at 23.7 and 47.4 mg boron/kg (only doses tested). LOAEL (rats) 

23.7 mg boron/kg. In a subchronic feeding study in dogs, 43.8 mg boron/kg but not 4.4 or 0.4 

45

mg boron/kg produced decreased packed cell volumes and hemoglobin levels. NOAEL (dogs) 

4.4 mg boron/kg. In a subchronic feeding study in mice, minimal to mild extramedullary 

hematopoiesis of the spleen was observed in all dosed groups (ca. 34, 68, 136, 272, or 544 mg 

boron/kg). LOAEL (mice) 34 mg boron/kg. There is also a case study in which an infant 

exposed to 43 mg boron/kg/day for 12 weeks developed anemia. 

Neurotoxicity. Ingestion of borax by human infants results in neurotoxicity. Case reports of 

nine infants who were exposed by sucking pacifiers dipped in a borax-honey mixture document 

similar findings of neurological symptoms (not specified) and seizures. For seven infants, doses 

are reported as 2 to 3 g borax/wk for 4 to 10 wk (ca. 4 to 16 mg boron/kg/day). Serum boron 

levels measured in three of the seven infants were elevated. For the other two infants, doses are 

reported as 125 mg borax/kg over a 12-wk period and 9 g borax over a 5-wk period (ca. 43 and 8 

mg boron/kg/day, respectively). The effects appear to be reversible upon cessation of exposure. 

Neurotoxicity testing is not recommended because animal studies do not appear to be predictive 

of this effect. 

Boundaries. The boundaries of this category are not yet well defined for health effects. All of 

the toxicity data are on boric acid or borax. A molecular weight cutoff of 1,000 is proposed, but 

there is no information from available toxicity data on a proper water solubility cutoff. 

General Testing Strategy. The OECD reproductive toxicity screen (OECD 421) with special 

additional attention to hematology. If this screen is positive for reproductive toxicity, a 

reproductive fertility study in rats according to the OPPTS Harmonized Test Guidelines 

(870.3800) is recommended. 

In cases in which exposures are exclusively dermal, a dermal absorption study (either in 

vivo or in vitro) could be conducted to refine the dermal risk assessment. If the in vivo study is 

selected, the test material should not be corrosive. If there is some uncertainty as to the 

corrosivity of the neat test material, a dermal irritation study should be undertaken first. If the 

neat material is corrosive, dilution to a noncorrosive concentration with a vehicle such as acetone 

or the alcohol used to make the ester is recommended. 

Environmental Toxicity: 

Most of the toxicity information for boron compounds is for boric acid and sodium 

tetraborate. These boron compounds show low acute toxicity towards fish (250.0 mg/L as a 

mean acute toxicity value) and daphnids (70.0 mg/L as a mean acute toxicity value), but 

moderate toxicity towards green algae (20.0 mg/L as a mean EC50 value). However, these 

compounds exhibit large acute to chronic ratios (ACR) towards fish (125 as a mean ACR) and 

the difference between the EC50 value and the chronic value (ChV) in green algae is large 

(about 117 as a mean difference). The mean ACR for daphnids is 8. The mean ChVs for fish, 

daphnids, and green algae are 2.0 mg/L, 9.0 mg/L, and 0.170 mg/L, respectively. Green algae 

appears to be the most sensitive group of species with respect to boric acid and sodium 

tetraborate. 

46

There are only screening data for fish for borate esters, specifically, only for 

tributylborate. These screening data showed no effects at 10.0 mg/L for 24 hours towards three 

species of fish. However, the purity of the tributylborate was not given. 

The only data for boranes are for tert-butylamine borane. These data are: fish 96-h LC50 

= 13.0 mg/L, daphnid 96-h LC50 = 0.700 mg/L, green algal 7-d EC50 = 3.0 mg/L, and algal 

ChV = 0.300 mg/L. 

The only toxicity information for boron hydrides are for mammals. These data show that 

all boron hydrides are highly toxic and more toxic than borates. 

The major environmental hazard concerns for this category are for chronic toxicity 

towards fish and toxicity towards green algae. 

Since there is no SARs for boron compounds, hazard profiles are developed using the 

nearest analog(s). 

Boundaries. Boron compounds must have water solubilities equal to or greater than 1.0 :g/L 

(ppb) and molecular weights generally need to be near or below 1000. 

Environmental Fate. Certain borates are subject to hydrolysis under environmentally realistic 

conditions. 

General Testing Strategy. 

The following testing strategy will address aquatic toxicity concerns: 

I. Release to Aquatic Ecosystems: 

Tier 1a. If the hydrolysis rate for any member of this class is predicted to be slow (t1⁄2 > 2 

days) or if hydrolysis will result in one or more products which are expected to be just as toxic as 

the parent borate, then the fish and daphnid acute toxicity tests from the aquatic base set of 

environmental toxicity tests will be recommended for aquatic exposures. The acute toxicity tests 

for fish (40 CFR 797.1400 or OPPTS 850.1075) and daphnids (40 CFR 797.1300 or OPPTS 

850.1010) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; the highest treatment 

concentration on a nominal-basis should equal the aqueous solubility limit; and solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

The algal toxicity testing (40 CFR 797.1050 or OPPTS 850.5400), should be done with 

static methods; measured concentrations; effective concentrations based on 100% active 

ingredients (AI) and mean measured concentrations; statistical analysis of effective 

47

concentrations at 24, 48, 72, and 96 hours; test medium with at least 0.300 mg/L EDTA as a final 

concentration; the highest treatment concentration on a nominal-basis equal to the aqueous 

solubility limit; and solvent can be used to assist the PMN to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the PMN beyond its 

aqueous solubility limit. 

If there is no significant risk from the PMN after the results of the environmental base set 

of tests have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 1b. If the hydrolysis rate for any member of this class is predicted to be rapid (t1⁄2 < 

2 days) and if hydrolysis will result in products which are expected to be significantly less toxic 

as the parent borate, then hydrolysis as a function of pH and temperature (40 CFR 796.3510 or 

OPPTS 835.2130) will be recommended. 

If the resulting hydrolysis t1⁄2 is < 2 days, then this result will be integrated into a new 

risk assessment for the PMN. However, the resulting hydrolysis t1⁄2 > 2 days, then the 

environmental base set will be recommended. 

If there is no significant risk from the PMN after the results of the environmental base set 

of tests have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 2. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR 797.1600 or OPPTS 850.1400), with flow-through methods; measured concentrations; 

effective concentrations based on 100% active ingredients (AI) and mean measured 

concentrations; and statistical analysis of effective concentrations at days 7, 14, 21, and 28. 

Daphnid chronic toxicity testing (40 CFR 797.1330 or OPPTS 850.1300), with flowthrough methods; measured concentrations; effective concentrations based on 100% active 

ingredients (AI) and mean measured concentrations; statistical analysis of effective 

concentrations at days 7, 14, and 21. 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 or OPPT 835.3100 

Modified Sturm Test 40 CFR 796.3260 or OPPT 835.3110 

Closed Bottle Test 40 CFR 796.3200 or OPPT 835.3110 

Modified OECD Screening Test 40 CFR 796.3240 or OPPT 835.3110 

Modified MITI Test (I) 40 CFR 796.3220 or OPPT 835.3110 

Modified AFNOR Test 40 CFR 796.3180 or OPPT 835.3110 

II. Release to terrestrial Ecosystems: The terrestrial base set of environmental toxicity tests (i.e., 

48

the early seeding growth test, the earthworm toxicity test and the soil microbial community 

bioassay) will be recommended for terrestrial exposures. Chronic toxicity testing for terrestrial 

organisms include: the plant whole life cycle test, the plant uptake test, and the soil microbial 

community bioassay. 

July, 1991; revised August, 1997. 

49

Category: Cationic Dyes Environmental Toxicity 

Definition. Any dye bearing one or more net permanent positive charges is considered to be a 

member of this class. A "typical" new chemical of concern is a water soluble monoazo dye with 

a single delocalized positive charge. 

Hazard Concerns. Water soluble cationic dyes are toxic to fish, daphnids, and algae. Poorly 

soluble dyes tend to be toxic only to algae. No relationship between structure and activity has 

been found for cationic dyes. 

Boundaries. There are no established boundaries for cationic dyes. There is no molecular 

weight threshold - one dye with a molecular weight of 3,000 and bearing four positive charges 

was found to be toxic to fish. 

Testing. To adress environmental concerns, the base set of environmental toxicity tests (i.e., the 

fish acute toxicity test, the daphnid acute toxicity test and the green algal toxicity test) is 

recommended. These tests are to be done using the static method and nominal concentrations. 

In addition, two additional fish acute toxicity tests are recommended with known amounts of 

humic acid added to the dilution water. This testing is necessary to measure the mitigating 

effects of dissolved organic carbon (DOC) on the toxicity of the cationic dye. One test will be 

done with 20 mg humic acid/L in dilution and the second test will have 10 mg humic acid/L in 

dilution water. Total organic carbon (TOC) will be measured three times in each test and the 

TOC of the clean dilution water will also be measured at the beginning of the test. 

If DOC mitigates the environmental risk to water column organisms, then testing using natural 

sediments and organisms known to ingest sediment may be recommended. 

March, 1990 

50

Category: Cationic (quaternary ammonium) surfactants Environmental Toxicity 

Definition. 

Any cationic surfactant is a member of this category, for example: 

CH3 

| 

CH3-N+-(CH2-)15-CH3 Br­

| 

CH3 

Hazard Concerns. Cationic surfactants are biocidal to a wide array of species in the 

environment. Toxicity increases exponentially with increasing carbon chain length up to 16 

carbons and then decreases with increasing chain length. QSAR (quantitative structure-activity 

relationships) have been developed to predict toxicity. 

Boundaries. Little toxicity is observed when the carbon chain length exceeds 22. Tight ion 

pairs will not be significantly toxic. 

General Testing Strategy. To address ecotoxicity concerns, base set aquatic toxicity testing in 

algae, daphnids, and fish, plus humic acid testing in fish (20 mg/L humic acid in dilution water 

and 10 mg/L) is recommended. All testing uses static method, nominal concentrations. 

March, 1990 

51

Category: Cobalt Environmental Toxicity 

This category includes but is not limited to inorganic and organic compounds of cobalt 

(Co), e.g., soluble cobalt cations, cobalt esters, and organocobalt compounds. 

Hazard Concerns. 

Most of the toxicity information for inorganic cobalt compounds is for the soluble salts: 

chloride, nitrate, and sulfate. There are no known data for organoCo compounds, organic acid 

chelates with Co, or for Co esters. 

The best toxicity data for Co are listed below with predicted (P) and measured (M) 

toxicity values indicated and effective concentrations in mg Co/L (ppm): 

fish (FHM) 96-h LC50 

daphnid 48-h LC50 

daphnid 48-h LC50 

WQ 2° acute value 

green algal 7-d EC50 

RTELS 28-d LC50 

fish ChEC20 

fish Chronic Value (ChV) 

fish ACR 

daphnid ChEC20 

daphnid ChV 

daphnid ChV 

daphnid ACR 

WQ 2° chronic value 

algal ChV 

Abbreviations: 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

= 

48.0 M S,?,H130,Cl E86

1.32 M Cl B&S74

1.11 M S,N,H45,Cl B&C72

0.195 P S96

0.160 M S,? NO3,Cl,SO4 St81

0.470 M SR12h,?,H104,NO3 B78

0.810 M S96

0.290 M S96

170.0 P

0.004 M S96

0.010 M S,N,H45,Cl B&C72

0.005 M S96

110.0 P B&C72

0.003 P S96

0.040 P EC50÷ChV=4

ACR = acute-to-chronic ratio;

Ch = chronic;

ChV = chronic value;

CC = concern concentration;

ELS = early life stage;

FHM = fathead minnow;

H = hardness as CaCO3;

N = nominal concentrations;

? = method unknown;

RT = rainbow trout;

S = static method;

SR12h = static renewal method with renewals every 12 hours; and 

52

WQ = water quality value. 

Predictions were based on SARs for inorganic Co compounds; pH 7; hardness <180.0 mg/L as 

CaCO3; 100% active ingredients; mean measured concentrations of Co; and total organic 

carbon (TOC) <2.0 mg/L; 

Environmental concerns for Co compounds: 

moderate concern for acute toxicity to fish; 

moderate concern for acute toxicity to daphnids; 

high concern for toxicity to green algae; 

moderate concern for chronic toxicity to fish; 

high concern for chronic toxicity to daphnids; 

high concern for toxicity to green algae; 

assessment factor (AsF) = 10.0 

COC for fish = 0.030 

COC for daphnids = 0.001 

COC for green algae = 0.004 

The aquatic toxicity for the chelates and esters of Co are expected to be less than 

predicted using toxicity data based on the soluble ion and with a MW adjustment. 

The aquatic toxicity for organoCo could be higher than predicted using toxicity data 

based on the soluble ion and with a MW adjustment because the organic portion could enhance 

uptake in aquatic organisms. It is assumed that (1) the MWs of organoCo compounds would 

have to be less than 1000 daltons and (2) the log Kow of any organoCo would have to be less than 

8.0 for toxicity to aquatic organisms to occur. It is also assumed that the aquatic toxicity of 

organoCo compounds will increase with increasing Kow when the log Kow <8.0. 

The major environmental toxicity concerns for this category are for chronic toxicity 

towards daphnids and toxicity towards green algae. The acute-to-chronic ratios of Co towards 

fish and daphnids are both greater than 100. The SAR method for Co compounds is the nearest 

analog(s) method. 

Boundaries. 

Cobalt compounds must have water solubilities equal to or greater than 1.0 :g/L (ppb) 

and molecular weights generally need to be near or below 1000. The log K

compounds has to be <8.0. ow of organoCo 

53

Fate: 

General Testing Strategy: I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (OPPTS 850.1075) and daphnids (OPPTS 

850.1010) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; ideally, mean measured 

concentrations in the highest treatment concentration should be equal the aqueous solubility 

limit; and solvent can be used to assist the test chemical to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the test chemical 

beyond its aqueous solubility limit. Stock solutions in water should be adjusted to pH near 7.0. 

The algal toxicity testing (OPPTS 850.5400), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; ideally, mean 

measured concentrations in the highest treatment concentration should be equal the aqueous 

solubility limit; and solvent can be used to assist the test chemical to reach its aqueous solubility 

limit quicker, but cannot be used to artificially enhance the water solubility of the test chemical 

beyond its aqueous solubility limit. Stock solutions in water should be adjusted to pH near 7.0. 

If there is no significant risk from the test chemical after the results of the environmental 

base set have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 2. For organoCo compounds, or chelates or esters of Co, aerobic biodegradability 

according to either of the following test guidelines: 

Ready Biodegradability OPPTS 835.3110 

Sealed Vessel CO2 Production Test OPPTS 835.3120 

If there is no significant risk from the test chemical after the results of biodegradation 

testing have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing 

(OPPTS 850.1400), with flow-through methods; measured concentrations; effective 

concentrations based on 100% active ingredients (AI) and mean measured concentrations; 

statistical analysis of effective concentrations at days 7, 14, 21, and 28; measured TOC of 

dilution water in the control; ideally, mean measured concentrations in the highest treatment 

concentration should be equal the aqueous solubility limit; solvent can be used to assist the test 

chemical to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance 

54

the water solubility of the test chemical beyond its aqueous solubility limit; and the 7-d ELS 

stage toxicity test cannot be substituted for the 28-d ELS toxicity test because the 7-d ELS 

toxicity test may underestimate chronic toxicity measured by the 28-d ELS toxicity test when the 

Chronic Values are compared. Stock solutions in water should be adjusted to pH near 7.0. 

Daphnid chronic toxicity testing (OPPTS 850.1300), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; ideally, mean measured concentrations in 

the highest treatment concentration should be equal the aqueous solubility limit; solvent can be 

used to assist the test chemical to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the test chemical beyond its aqueous solubility limit; 

and the 7-d daphnid chronic toxicity test cannot be substituted for the 21-d toxicity test because 

the fish 7-d ELS toxicity test may underestimate chronic toxicity measured by the fish 28-d ELS 

toxicity test when the chronic values are compared. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test, the earthworm toxicity test and the soil microbial 

community bioassay) will be recommended for terrestrial exposures. Chronic toxicity testing for 

terrestrial organisms include: the plant whole life cycle test, the plant uptake test, and the soil 

microbial community bioassay. 

References. 

B78 = Birge. 1978. USDOE Tech Info

B&C72 = Biesinger&Christensen. 1972. J Fish Res Brd Can 29:1691

B&S74 = Baudouin&Scoppa. 1974. Bull Environ Contam Toxicol 12:745

E86 = Ewell etal. 1986. Environ Toxicol Chem 5:831

S96 = Suter, GW. 1996. Environ Toxicol Chem 15:1234

St81 = Stokes. 1981. J Plant Nutrit 3:667

September, 1996. 

55

Category: Diazoniums Environmental Toxicity 

This category includes only aromatic diazoniums (N/N+). Aliphatic diazoniums are very 

explosive and are only used as synthesizing agents. Aromatic diazoniums are used as fungicides 

on seeds and in soil, e.g., Fenaminosulf. It is known that diazoniums need to be absorbed to be 

toxic. Test data submitted to the Agency in the New Chemicals Program showed that diazo 

compounds with a number average molecular weight (MWn) > 1000 have no effects at 

saturation to fish in the acute toxicity test. Therefore, compounds with MWn's > 1000 will be 

excluded from this category regardless of water solubility. In the NEAT state, diazoniums are 

solids, i.e., salts, and are most are soluble in aqueous media. Acute toxicity for diazoniums is 

assumed to be limited by the octanol/water partition coefficient (Kow; with a missing fragment 

for N/N+) and MW. Above a log Kow value of => 8.0 and/or MW = 1000, diazoniums are not 

expected to be toxic at saturation during 96-h exposures. Diazoniums are expected to be similar 

to anilines with respect to their Kow cutoff value for acute toxicity. This assumes that the missing 

fragment for N/N+ = -1.0. The acute toxicity of anilines diminishes at about a log Kow = 7.0 

(Veith and Broderius 1987). There are no known Kow limits for chronic toxicity at this time, but 

it may not be much above a log Kow = 10.0 for diazoniums. Future testing will determine this 

Kow limit. 

Hazard Concerns. The acute toxicity for diazoniums has been determined through SAR 

Analysis: 

log fish 96-h LC50 (millimoles/L) = -2.456 - 0.331 log Kow 

based on a log Kow for the diazonium using CLOGP Ver. 3.3 with a missing fragment for N/N+, 

N = 3, and R2 = 0.98. Acute toxicity values are assumed to be valid through log Kow = 8.0. 

Daphnids are assumed to have similar sensitivity to fish, but green algae are expected to be more 

sensitive based on the use of diazoniums as fungicides. 

Fate: Diazonium fungicides, e.g., Fenaminosulf, are sensitive to light but is stabilized with Na 

sulphite. Fenaminosulf is stable in alkaline media. Diazoniums are also used in photography, 

e.g., diazo reproduction paper and film. Therefore, diazoniums are expected to be subject to 

rapid direct and indirect photolysis under environmentally realistic conditions. Diazoniums are 

also expected to slowly hydrolyze to phenols. 

Boundaries.: There are no known lower boundaries. The upper boundaries will be based on 

Kow and MW. Acute toxicity expected with log Kow < 8.0 with a missing fragment for N/N+

.; 

no effects at saturation during 96-h exposures when log Kow >= 8.0. Chronic toxicity has no 

known upper bound for log Kow, but it is probably near 10.0 with a missing fragment for N/N+. 

MW must be < 1000. The environmental base set of tests will be requested for aquatic releases 

and the terrestrial base set of tests will be recommended for terrestrial exposures. When the log 

Kow is >= 10.0, chronic toxicity testing with fish and daphnids will be recommended. 

56

General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. Since diazoniums compounds are photosensitive to uv light, it is best to avoid 

the use of fluorescent lights in toxicity tests. If they are used, then glass filters should be used. 

The acute toxicity tests for fish (CFR §797.1400) and daphnids (CFR §797.1300) will be done 

using the flow-through method with measured concentrations; effective concentrations will be 

based on 100% active ingredients (AI) and mean measured concentrations; measured TOC of 

dilution water in the control; the highest treatment concentration on a nominal-basis should not 

exceed the aqueous solubility limit; and solvent can be used to assist the PMN to reach its 

aqueous solubility limit quicker, but cannot be used to artificially enhance the water solubility of 

the PMN beyond its aqueous solubility limit. 

The algal toxicity testing (CFR §797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis cannot exceed the PMN's aqueous solubility limit; 

and solvent can be used to assist the PMN to reach its aqueous solubility limit quicker, but 

cannot be used to artificially enhance the water solubility of the PMN beyond its aqueous 

solubility limit. 

If there is no significant risk from the PMN after the results of the environmental base set 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 2. 

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, go to Tier 4. 

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40.796.3765 (b)(2) and (c)(2)], expose to sunlight 

for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive species 

from environmental base set. For example, the most sensitive species from the environmental 

base set has an EC50 value = 2.0 mg PMN/L (based on 100% active ingredients [AI]), therefore, 

prepare a 5.0 mg PMN per liter stock solution based on 100% AI using the standard humiccontaining solution. This stock solution is exposed to sunlight for at least 6 half-lives to ensure 

that all of the PMN has been photolyzed, and then this stock solution is used to retest the most 

sensitive aquatic species to determine if the photolysis products of the PMN are more or less 

57

toxic that the PMN. 

Tier 4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (CFR 

§797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; the highest treatment concentration on a nominal-basis should not exceed the aqueous 

solubility limit of the PMN; solvent can be used to assist the PMN to reach its aqueous 

solubility limit quicker, but cannot be used to artificially enhance the water solubility of the 

PMN beyond its aqueous solubility limit; and the 7-d ELS stage toxicity test cannot be 

substituted for the 28-d ELS toxicity test because Van Leeuwen et al (1990) have demonstrated 

that the 7-d ELS toxicity test underestimated the chronic toxicity of anilines measured by the 28-

d ELS toxicity test by >5.3 times when the NOECs were compared (see Table VII in Van 

Leeuwen); 

Daphnid chronic toxicity testing (CFR §797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; the highest treatment concentration on a 

nominal-basis should be set at the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN beyond its aqueous solubility limit; and the 7-d daphnid chronic 

toxicity test cannot be substituted for the 21-d toxicity test 

because Van Leeuwen et al (1990) have demonstrated that the fish 7-d ELS toxicity test 

underestimated the chronic toxicity of anilines measured by the fish 28-d ELS toxicity test by 

>5.3 times when the NOECs were compared (see Table VII in Van Leeuwen). 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test, the earthworm toxicity test, the avian acute oral toxicity 

test, and the soil microbial community bioassay) will be recommended for terrestrial exposures. 

Chronic toxicity testing for terrestrial organisms include: the plant whole life cycle test, the 

plant uptake test, avian reproduction toxicity test, and the soil microbial community bioassay. 

58

References. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

Veith GD and Broderius SJ. 1987. Structure-toxicity relationships for industrial chemicals 

causing type (II) narcosis syndrome. In Kaiser KLE (ed), QSAR In Environmental Toxicology -

II, p 385-391. Reidel Publishing Company. 

November, 1991 

59

Category: Dichlorobenzidine-based Pigments Human Health 

Environmental Toxicity 

Other Names: Diarylide Pigments, DCB Pigments, Pigment Yellows 

Definition: Any diazo pigment containing the substructure, dichlorobenzidine, and coupled 

with acetoacetanilide. 

Hazard Concerns. There are oncogenicity/mutagenicity concerns for dichlorobenzidine-based 

pigments based on the potential release of 3,3'-dichlorobenzidine and on the presence of residual 

(unbound) dichlorobenzidine. DCB is a known animal carcinogen and a suspect human 

carcinogen. In addition, DCB is known to bioconcentrate in the tissues of aquatic organisms. 

Boundaries. Concern for the intact pigment is restricted to uses at temperatures exceeding 

200o

C. Data submitted to the Agency under TSCA section 8(e) show that DCB pigments break 

down to release DCB as a vapor from colored polymers when heated to extrusion temperatures 

(> 200oC) and, from sheetmetal coatings during curing. Though little information exists on the 

biodegradation of pigments in sediments, data on other low water soluble colorants, indicate that 

biodegradation may occur over a period of months, possibly resulting in the release of DCB. 

General Testing Strategy. 

EPA's New Chemicals Program considers the following tests to be appropriate to address the 

potential for DCB pigments to pose a significant risk to health or the environment: 

1. Monitoring data to detect the presence of DCB under actual conditions of use; 

temperature, dwell time, % pigment in polymer or coating, and type of polymer or coating. 

2. If there are releases to water, an anaerobic biodegradation assay. 

60

References: 

Appleton HT, Sikka HC. 1980. Accumulation, elimination, and metabolism of 3,3'-

dichlorobenzidine in the bluegill sunfish. Environ Sci Technol 14:50-54. 

Pliss GB. 1963. On some regular relationship between carcinogenicity of aminobiphenyl 

derivatives and the structure of the substance. Acta Unio Int Cancrum 19:499-501. 

Stula EF, Sherman H, Reinhardt CF. 1975. Experimental neoplasia in rats from oral 

administration of 3,3'-dichlorobenzidine, 4,4'-methylene-bis(2-chloroaniline), and 4,4'-

methylene-bis(2-methylaniline). Toxicol Appl Pharmacol 32:159-176. 

Stula EF, Barnes JR, Sherman H. 1978. Liver and urinary bladder tumors in dogs from 3,3-

dichlorobenzidine. 1978. J Environ Pathol Toxicol 1:475-490. 

TSCA Section 8(e) Documents: 

8EHQ-0490-0962 INIT 

8EHQ-0590-0962 SUPPL 

8EHQ-0690-0962 FLWP 

8EHQ-0790-0962 SUPPL 

8EHQ-0890-0962 SUPPL 

March, 1994 

61

Category: Dithiocarbamates Environmental Toxicity 

This category includes N,N-dialkyldithiocarbamates (DDC); ethylenebisdithiocarbamates 

(BDC); and their metal salts which include but are not limited to zinc, sodium, iron, manganese, 

copper, lead, mercury, silver and selenium. The alkyl groups of the DDCs generally include, 

methyl through butyl, but may be larger. This category also includes the degradation products of 

DDC and BDC which may include disulfide moieties, sulfide moieties, thiourea moieties, urea 

moieties, polymeric sulfide moieties, dithizaole-3-thiones, cyclic thioureas and cyclic ureas as 

indicated in the generic environmental hazard assessment. 

Hazard Concerns: Many members of this category are commercial insecticides, fungicides, 

disinfectants, rodenticides, antioxidants, slimicides, algalicides, bactericides and heavy metal 

chelators. Their mode of toxic action apparently results from interference with metallo-enzymes 

in living cells; the toxicity has been attributed to either DDCs and BDCs or their degradation 

products. All of the known dithiocarbamates are acutely toxic to fish, algae and bacteria at < 10 

mg/L, and to aquatic invertebrates at < 1 mg/L. Chronic toxicity to fish and aquatic invertebrates 

ranges from 0.001 to 2 mg/L and 0.011 to 0.111 mg/L, respectively. In general, the SARs for the 

dithiocarbamates and their degradation products are sigmoidal with acute and chronic toxicity 

increasing with increasing Kow. The sigmoidal relationship between Kow and toxicity of the 

dithiocarbamates is very poor statistically. Consequently, toxicity predictions will be made 

using either the closest analog or averaging data for the two closest analogs which bracket the 

dithiocarbamate under question. The SAR for the degradation products is much more robust and 

a series of SARs will be used to predict acute toxicity of degradation products toward fish, 

daphnids and Photobacterim phosphoreum; and chronic toxicity toward fish, daphnids and green 

algae. 

Boundaries: There are no known lower boundaries. The upper boundaries are based on K

and MW. When the log Kow value is < 5 mg/L, the environmental base set of tests will be 

requested for aquatic releases and the terrestrial base set of tests will be recommended for 

ow 

62

terrestrial exposures. When the log Kow is between 5 and < 19, only chronic toxicity testing will 

be recommended. When the log Kow is > 19 (CLOGP), no testing will be requested because no 

toxic effects at saturation will be expected. Generally, members of this category will have MWs 

of less than 1000. 

General Testing Strategy 

Tier 1. The acute aquatic base set of environmental toxicity tests will be recommended 

for aquatic exposures and the terrestrial base set of environmental toxicity tests (i.e., the early 

seeding growth test, the earthworm acute toxicity test and the soil microbial community 

bioassay) will be recommended for terrestrial exposures. 

Tier 2. If acute toxicity testing indicates a significant risk, then chronic toxicity with fish 

and aquatic invertebrates will be recommended as well as aerobic biodegradation testing. 

Aerobic biodegradability can be determined using one of the following test guidelines, 

listed in approximate order of preference: 

Aerobic aquatic biodegradation

Modified Sturm test

Closed bottle test

Modified OECD screening test

Modified MITI test (I)

Modified AFNOR test

August 1989; revised November 1995 

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

63

Category: Epoxides Human Health 

Environmental Toxicity 

Definition. Any molecular structure containing one or more epoxy groups is considered to be a 

member of the category: 

O


/ \


-C---C­


| |


Hazard Concerns. Health concerns for epoxides are for cancer and reproductive effects based 

on data for several analogous chemicals. There is greater concern for primary epoxides, 

O


/ \


-C---CH


H H


than for epoxides with substitutions on both of the epoxy carbons. Environmental toxicity is a 

function of the octanol-water partition coefficient. Compounds with log P's >5 act as neutral 

organics producing simple narcosis, but at lower log P's, epoxides display toxicity greater than 

that predicted for simple narcotics. A QSAR (quantitative structure-activity relationship) to 

predict the environmental toxicity of epoxides is under development. 

Boundaries. Structures with epoxy equivalent weights of >1,000 are presumed not to pose a 

hazard under any conditions. Concerns are confined to those species with molecular weights 

<1,000. Health concerns are restricted to species with molecular weights <500 if exposure is 

limited to the dermal route. 

Testing. To address health concerns the following tests are usually recommended for members 

of this class: (1) a lifetime cancer bioassay by the expected route of exposure, and (2) a 90-day 

subchronic with attention to pathology of the reproductive organs. To address ecotoxicity 

concerns, base set acute aquatic toxicity testing (algae: static method, daphnid and fish: flowthrough method, all measured concentrations). 

September, 1988 

64

Category: Esters Environmental Toxicity 

This category includes all esters, polyesters, vinyl esters, allylic esters, propargylic esters, 

aliphatic esters, aromatic esters, carboxylic acid esters, and sulfonate esters. These compounds 

need to be absorbed to be toxic, therefore, compounds with MWs > 1000 will be excluded from 

this category. Acute toxicity for esters which are liquids at room temperature is known to be 

limited by the octanol/water partition coefficient (Kow). Above a log Kow value of => 5.0, esters 

show no effects at saturation during 96-h exposures (Veith et al 1984). Esters which are solids at 

room temperature may show no toxicity at saturation at lower Kow values depending on the 

melting point, i.e., the higher the melting point at a given Kow, the greater the likelihood that no 

acute toxicity will be observed at saturation. For solids, the no-effects-at-saturation point has to 

be determined on a case-by-case basis. The Kow limit for chronic toxicity is set at a log Kow = 8 

for liquid esters. For solid esters, chronic toxicity testing will determine this Kow limit. 

Hazard Concerns. The toxicity for simple esters has been determined through SAR Analysis 

(Clements 1988). Esters are known to be more toxic than neutral organic chemicals, and this 

excess toxicity decreases with increasing Kow. The toxicity for vinyl esters, allylic esters, and 

propargylic esters is expected to be greater than for simple esters. Again, the additional excess 

toxicity of these vinyl esters, allylic esters, and propargylic esters is expected to decrease with 

increasing Kow. 

Members of this category exhibit toxicity ranging from low toxicity (i.e., > 100 mg/L) to high 

toxicity (i.e., < 1 mg/L) depending on their Kow, MW, and melting point.

Boundaries. There are no known lower boundaries. The upper boundaries will be based on Kow 

and MW. Acute toxicity is expected when log Kow < 5.0; no effects at saturation during 96-h 

exposures when log Kow > 5.0. The upper boundary for chronic toxicity is 8.0. MW will be < 

1000. The environmental base set of tests will be requested for aquatic releases and the 

terrestrial base set of tests will be recommended for terrestrial exposures. When the log Kow is > 

5.0, chronic toxicity testing with fish and daphnids will be recommended. 

Fate: Esters are subject to both abiotic and biotic hydrolysis, i.e., ester hydrolysis, and aerobic 

biodegradation. Aerobic biodegradation is expected to be the dominant route of transformation 

in the environment. 

General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (40 CFR §797.1400) and daphnids (40 CFR 

§797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; the highest treatment concentration on a nominal-basis should not exceed the 

aqueous solubility limit; and solvent can be used to assist the ester to reach its aqueous 

solubility limit quicker, but cannot be used to artificially enhance the water solubility of the ester 

65

beyond its aqueous solubility limit. 

The algal toxicity test (40 CFR §797.1050) should be done with the static method; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis should not exceed the aqueous solubility limit of the 

ester; and solvent can be used to assist the ester to reach its aqueous solubility limit quicker, but 

cannot be used to artificially enhance the water solubility of the ester beyond its aqueous 

solubility limit. 

If there is no significant risk from the ester after the results of the environmental base set 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 2. 

Tier 2. Aerobic biodegradability according to any one of the following test guidelines 

(listed in order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

If there is no significant risk from the ester after the results of the aerobic biodegradation 

testing have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR §797.1600), with flow-through methods; measured concentrations; effective 

concentrations based on 100% active ingredients (AI) and mean measured concentrations; 

statistical analysis of effective concentrations at days 7, 14, 21, and 28; the highest treatment 

concentration on a nominal-basis should not exceed the aqueous solubility limit of the tested 

chemical; solvent can be used to assist the ester to reach its aqueous solubility limit quicker, but 

cannot be used to artificially enhance the water solubility of the ester beyond its aqueous 

solubility limit; and the 7-d ELS stage toxicity test cannot be substituted for the 28-d ELS 

toxicity test because Van Leeuwen et al (1990) have demonstrated that the 7-d ELS toxicity test 

underestimated the chronic toxicity of anilines measured by the 28-d ELS toxicity test by >5.3 

times when the NOECs were compared (see Table VII in Van Leeuwen). Both anilines and 

esters are more toxic than predicted based on narcosis alone, i.e., both esters and anilines have 

excess toxicity due to a more specific mode(s) of toxic action. A seven day exposure may not 

allow enough time for this excess toxicity to be expressed either because of not enough exposure 

and/or not enough time for metabolic activation. 

Daphnid chronic toxicity testing (40 CFR §797.1330), with flow-through methods; 

66

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; the highest treatment concentration on a nominal-basis should not exceed the aqueous 

solubility limit of the ester; solvent can be used to assist the ester to reach its aqueous solubility 

limit quicker, but cannot be used to artificially enhance the water solubility of the ester above its 

aqueous solubility limit; and the 7-d daphnid chronic toxicity test cannot be substituted for the 

21-d toxicity test (Van Leeuwen et al 1990). 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity tests 

(i.e., the early seeding growth test, the earthworm toxicity test, the avian acute oral toxicity test, 

and the soil microbial community bioassay) will be recommended for terrestrial exposures. 

Chronic toxicity testing for terrestrial organisms include: the plant whole life cycle test, the 

plant uptake test, the avian reproductive toxicity test, and the soil microbial community bioassay. 

References. 

Clements, RG (editor). 1988. Estimating toxicity of industrial chemicals to aquatic organisms 

using structure-activity relationships. EPA-560-6-88-001. Washington, DC: Environmental 

Effects Branch, Health and Environmental Review Division, Office of Toxic Substances (TS796), United States Environmental Protection Agency. Available from the National Technical 

Information Service, Springfield, VA 22161, PB89-117592. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

Veith GD, DeFoe D, and Knuth M. 1984. Structure-activity relationships for screening organic 

chemicals for potential ecotoxicity effects. Drug Metabolism Reviews 15(7):1295-1003. 

November, 1991 

67

Category: Ethylene Glycol Ethers Human Health 

Definition. The ethylene glycol ether category is defined as follows: 

R-(OCH2CH2)n-OR' 

n = 1, 2, or 3 

R = alkyl C7 or less or phenyl or alkyl substituted phenyl 

R' = H or alkyl C7 or less or any group that can be chemically or 

metabolically removed to yield a glycol ether 

Hazard Concerns. Short-chain ethylene glycol ethers are absorbed by all routes of exposure 

and have caused irritation of skin, eyes, and mucous membranes; hemolysis, bone-marrow 

damage, and leukopenia of both lymphocytes and granulocytes; direct and indirect kidney 

damage; liver damage, immunotoxicity, and central nervous system (CNS) depression. Shortchain ethylene glycol ethers are also developmental and reproductive toxicants. 2-

Phenoxyethanol is known to cause hemolysis and eye irritation. 

Boundaries. There is evidence that developmental toxicity is reduced going from the methyl to 

the butyl ether, and that it is reduced going from the ethylene glycol to the triethylene glycol. 

However, there is still a concern for maternal toxicity as reflected in developmental and 

subchronic toxicity studies. The systemic toxicity of longer-chain glycol ethers and alkylphenyl 

glycol ethers is uncertain because data are not available. The alkyl chain length of C7 or less was 

chosen as a boundary for short-chain ethylene glycol ethers based on the available data. 

General Testing Strategy 

The New Chemicals Program considers the following tests to be the most appropriate for 

ethylene glycol ethers with sufficient exposure to potentially pose an unreasonable risk: 

Tier 1 - Combined Repeated Dose Toxicity Study with the Reproduction/Developmental 

Toxicity Screen Test (OECD Guideline 422). If signs of hematuria are seen red and white blood 

cell counts should be taken 2 days later except for female animals during pregnancy and 

lactation. 

Tier 2 - The need for further testing would be determined by the results of Tier 1. This could 

include any of the following tests. 

Prenatal Developmental Toxicity via the most appropriate route (40 CFR 799.9370) 

2-Generation Reproduction Study via the most appropriate route (40 CFR 799.9380) 

90-Day Subchronic Study via the most appropriate route (40 CFR 799.9346 - inhalation route; 

870.3250 - dermal route; 870.3150 - oral route) 

68

Immunotoxicity Study via the most appropriate route (OPPTS 870.7800) 

June 1992, revised December 1997 

69

Category: Hydrazines and Related Compounds Human Health 

Environmental Toxicity 

Definition: Any structure containing one or more of the following groups is considered to be 

a member of the category: 

Hazard Concerns: Concerns for carcinogenicity and chronic effects to liver, kidney, and 

blood are based on data for a number of hydrazines and related chemicals. In humans, 

hydrazine, itself, may affect the central nervous system, liver, and kidneys. The toxic effects of 

hydrazine exposure to humans may range from mild skin and eye irritation, and skin 

sensitization, to severe irritation and burns, pulmonary edema, CNS depression, as well as liver 

and kidney damage, which can lead to death. Hydrazine may also present a serious hazard to 

plant life and aquatic organisms. Ecotoxicity concerns are based on structure activity 

relationships (SAR) using data for a number of hydrazines and hydrazides. Hydrazine itself 

(N2H4), is known to be acutely toxic to aquatic organisms at low levels, algae at < 100 ppb, 200 

ppb for fish, and 30 ppb for daphnids. 

Boundaries: There are no established boundaries for this category. The "typical" new 

chemical member of the category is a discrete (class I) chemical with a molecular weight <500. 

There is a greater concern for chemicals with few substitutions on the functional group than for 

70

those with multiple substitutions. 

General Testing Strategy 

EPA considers the following tests to be appropriate to address health and ecotoxicity concerns: 

1. Lifetime cancer bioassay by the expected route of exposure in two species of rodents (40 

CFR 798.3300). 

2. 90-Day subchronic in one species of rodent by the expected route of exposure to assess 

effects to the liver, kidney, and blood (40 CFR 798.2650). 

3. Base-set ecotoxicity testing to include fish (40 CFR 797.1400) using the flow-through 

method, daphnids (40 CFR 797.1300) using the flow-through method and algae (40 CFR 

797.1050) using the static method, all measured concentrations. 

Results of the acute ecotoxicity testing may trigger chronic fish (40 CFR 797.1600) and 

daphnid (40 CFR 797.1350) testing. 

4. Environmental fate testing including, as appropriate, melting point (40 CFR 796.1300) or 

boiling point (40 CFR 796.1220), water solubility (40 CFR 796.1840 or 796.1860), log Kow (40 

CFR 796.1550, 796.1570 or 796.1720), vapor pressure (40 CFR 796.1950) and hydrolysis (40 

CFR 796.3500). For aromatic hydrazines and related compounds, the following additional 

testing is recommended; direct and indirect photolysis (40 CFR 796.3765), and aerobic 

biodegradation. 

Aerobic biodegradability can be determined using one of the following test guidelines, 

listed in approximate order of preference: 

Aerobic aquatic biodegradation

Modified Sturm test

Closed bottle test

Modified OECD screening test

Modified MITI test (I)

Modified AFNOR test

References. 

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

1. Bhide, S.V., R.A. D'Souza, M.M. Sawai, & K.J. Ranadive (1976). International Journal 

of Cancer 18: 530. 

2. Biancifiori, C (1970). Journal of the National Cancer Institute 44: 943. 

71

3. Biancifiori, C (1971). Lav. 1st Anat. Istol. Pat., Univ. Studi Perugia 31: 5. 

4. Biancifiori, C., E. Bucciarelli, D.B. Clayson, & F.E. Santilli (1964). British Journal of 

Cancer 18: 543. 

5. Hydrazine-RM2 Exit Document. OPPT Office Director's Meeting, Monday, December 

13, 1993. 

6. Juhasz, J., J. Balo, & B. Szende (1966). Nature (London) 210: 1377. 

7. Juhasz, J., J. Balo, & B. Szende (1967). Z. Krebsforsch 70: 150. 

8. Toth, B. (1969). Journal of the National Cancer Institute 42: 469. 

9. Toth, B. (1972). International Journal of Cancer 9: 109. 

September, 1988; revised June, 1994, revised October 1995. 

72

Category: Hindered Amines Human Health 

Definition. The category is at present not well defined. A "typical" new chemical hindered 

amine of concern has two or more hindered amine functional groups, usually the 2,2,6,6-

tetramethyl-4-piperidinyl group, and is used as a UV light stabilizer. 

Hazard Concerns. Health concerns for the category are based on data submitted to the Agency 

under §8(e) of TSCA for Tinuvin 144 and Chimassorb 944. The data indicate that these 

hindered amines, and presumably hindered amines similar in structure, are toxic to the immune 

system, liver, blood, the male reproductive system, and the G.I. tract. 

Boundaries. The boundaries of the category are not well defined. Tinuvin 144 has a molecular 

weight of 685, whereas Chimassorb 944 is a polymer with a number average molecular weight 

well in excess of 1,000. As a consequence, there is at present no molecular weight cutoff for 

hindered amines of concern to the new chemical program. 

It is assumed that there is little or no dermal absorption of problematic hindered amines 

because of their high molecular weights. Consequently, hindered amines in the new chemical 

program are only of concern if there is significant inhalation exposure associated with their 

manufacture, processing, or use. 

General Testing Strategy 

For hindered amines found to pose a potentially unreasonable risk, a 90-day oral subchronic test 

in rats is the recommended test. We have requested that emphasis be placed on hematology, the 

immune system, and on the male reproductive system. 

June 1990; revised March 1995 

73

Category: Imides Environmental Toxicity 

This category includes all imides and maleimides. Substitutions may be aliphatic, aromatic, 

and/or halogens. The mode of toxic action of imides is unknown, but halogenated imides are 

used as microbial pesticides, specifically, fungicides, bactericides, slimicides, and algicides. It is 

assumed that these compounds need to be absorbed to be toxic, therefore, compounds with MWs 

> 1000 will be excluded from this category. Acute toxicity for imides which are liquids at room 

temperature is assumed to be limited by the octanol/water partition coefficient (Kow), and the 

limiting Kow value for acute toxicity is assumed to be about 5.0. The limiting value for chronic 

toxicity is assumed to be about 8.0. Imides which are solids at room temperature may show no 

toxicity at saturation at log Kow values < 5.0 depending on the melting point, i.e., the higher the 

melting point at a given Kow, the greater the likelihood that no toxicity will be observed at 

saturation. For solids, the no-effects-at-saturation determination has to be made on a case-bycase basis. 

Hazard Concerns. The acute toxicity for imides and maleimides towards fish has been 

determined through SAR Analysis by EPA. The SAR for acute toxicity to fish is defined by the 

following regression equation: 

log 96-h LC50 = 1.256 - 0.76 log Kow 

where the LC50 is in milliMoles per Liter (mM/L), N = 4, and R2 = 0.98. The acute toxicity of 

imides towards daphnids is expected to be similar to that of fish, but their toxicity towards green 

algae is expected to be greater because of their use as microbial pesticides. 

Polyimides may be more toxic than predicted using this SAR. 

The toxicity of imides towards aquatic organisms can range from low (i.e., > 100.0 mg/L) to 

ow and MW. The higher the K

lower the MW, the higher the toxicity (or the lower the EC50 value). 

high toxicity (i.e., < 1.0 mg/L) depending on their K ow and the 

Boundaries.: There are no known lower log Kow and MW boundaries. The upper boundaries 

for acute toxicity will be set at a log Kow < 5.0; chronic toxicity limits will be set at a log Kow < 

8.0. MW will be < 1000 for stable compounds. The environmental base set of tests will be 

requested for aquatic releases and the terrestrial base set of tests will be recommended for 

terrestrial exposures. 

General Testing Strategy. 

The aquatic base set of environmental toxicity tests will be recommended for aquatic exposures. 

The acute toxicity tests for fish (40 CFR 797.1400) and daphnids (40 CFR 797.1300) will be 

done using the flow-through method with measured concentrations; effective concentrations 

will be based on 100% active ingredients (AI) and mean measured concentrations; measured 

TOC of dilution water in the control; the highest treatment concentration on a nominal-basis 

74

should equal the aqueous solubility limit; and solvent can be used to assist the PMN to reach its 

aqueous solubility limit quicker, but cannot be used to artificially enhance the water solubility. 

The algal toxicity testing (40 CFR 797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis equal to the aqueous solubility limit; and solvent can 

be used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility. 

Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 CFR 

797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; the highest treatment concentration on a nominal-basis should be set at the aqueous 

solubility limit; solvent can be used to assist the PMN to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility; and the 7-d ELS stage 

toxicity test cannot be substituted for the 28-d ELS toxicity test because Van Leeuwen et al 

(1990) have demonstrated that the 7-d ELS toxicity test underestimated the chronic toxicity of 

anilines measured by the 28-d ELS toxicity test by >5.3 times when the NOECs were compared 

(see Table VII in Van Leeuwen); 

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; the highest treatment concentration on a 

nominal-basis should be set at the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility; and the 7-d daphnid chronic toxicity test cannot be substituted for the 21-d 

toxicity test because Van Leeuwen et al (1990) have demonstrated that the fish 7-d ELS toxicity 

test underestimated the chronic toxicity of anilines measured by the fish 28-d ELS toxicity test 

by >5.3 times when the NOECs were compared (see Table VII in Van Leeuwen). 

The terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test 

[40 CFR 797.2800], the earthworm acute toxicity test [40 CFR 795.150], and the soil microbial 

community bioassay [40 CFR 795.3700]) will be recommended for terrestrial exposures. 

Chronic toxicity testing for terrestrial organisms include: the plant whole life cycle test [40 CFR 

797.2830], the plant uptake test [40 CFR 797.2850], and the soil microbial community bioassay. 

75

References. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

April, 1991 

76

Category: Diisocyanates Human Health 

Definition. Any molecular structure containing two or more isocyanate groups is considered to 

be a member of the category for new chemical purposes: 

R-(N=C=O)>2 

Members of the class include new isocyanate monomers as well as new oligomers, 

polymers, prepolymers, or reaction products of existing isocyanate monomers. Most new 

chemical diisocyanates of concern are polymers or oligomers containing well-known 

diisocyanate monomers such as toluene diisocyanate (TDI) or 4,4'-methylenediphenyl 

diisocyanate (MDI). 

Hazard Concerns. Diisocyanates are of concern for potential dermal and respiratory 

sensitization, and for pulmonary toxicity. Based on conflicting animal and human data for 

respiratory sensitization, the Agency has determined that there is presently not a reliable animal 

model for testing diisocyanates for potential respiratory sensitization. At this time, it is assumed 

that all diisocyanates may be potential human respiratory sensitizers. 

Most members of the diisocyanate category have not been tested for carcinogenic 

potential. Though the aromatic diisocyanates [MDI, TDI, dianisidine diisocyanate (DADI)] 

tested positive and one aliphatic diisocyanate [hexamethylene diisocyanate (HDI)] tested 

negative in one species, it is premature to make any generalizations about the carcinogenic 

potential of aromatic versus aliphatic diisocyanates. 

Boundaries. Structures with an isocyanate equivalent weight of >5,000 are presumed not to 

pose a hazard under any conditions. Typically, concerns are confined to those species with 

molecular weights <1,000. 

Frequently, new chemical isocyanates are manufactured with a significant excess of 

isocyanate monomer. Under these circumstances, the excess monomer is usually regarded as 

more hazardous than the "new" chemical component, and these PMN substances are ordinarily 

not regulated under §5 of TSCA. For the purposes of risk assessment within the New Chemicals 

Program, a PMN substance is considered "existing" if more than 50% of the free isocyanate 

groups in the PMN substance (new chemical component + existing chemical monomer) reside on 

unreacted monomer(s). This does not relieve a Company, however, of any obligations to submit 

a PMN for the new chemical isocyanate if indeed it is not listed on the TSCA Inventory. 

General Testing Strategy. The following testing is recommended to address the potential for 

pulmonary toxicity and dermal sensitization. 

1. Dermal sensitization (OPPTS 870.2600). 

77

 2. 90-day Subchronic inhalation toxicity test in rodents (OPPTS 870.3465). 

In addition, appropriate hazard communication needs to be developed and implemented. 

Health and Safety Information. The following information provides guidance in developing 

hazard communication and protective measures language to accompany new diisocyanate 

chemicals and formulations. It is based on the Agency’s current understanding of the hazards 

associated with diisocyanates and the most effective means to limit exposure. 

Warnings. Exposure to diisocyanates may cause the following human health 

effects: skin irritation and allergic reactions, respiratory irritation, respiratory 

sensitization, and lung toxicity; some diisocyanates also may cause cancer. The 

likelihood that these effects will occur depends on a number of factors; among 

them, the level of exposure, frequency of exposure, part of the body exposed, and 

sensitivity of the exposed individual. 

Symptoms of allergic reaction and respiratory sensitization include rashes, cough, shortness of 

breath, asthma, chest tightness and other breathing difficulties. There is uncertainty as to the 

mechanism by which sensitization occurs. In sensitized individuals, exposure to even small 

amounts of diisocyanates (below government-recommended workplace exposure levels) may 

cause allergic respiratory reactions like asthma and severe breathing difficulties. It is especially 

important to note that contact with skin may lead to respiratory sensitization or cause other 

allergic reactions. In some cases, the effects of diisocyanate exposure may be immediate and 

life-threatening; in others, the effects may be delayed and occur hours after the exposure has 

ended. Repeat or prolonged exposure to diisocyanates may also cause irritation to eyes, skin, 

respiratory tract and lungs, as well as adverse chronic lung effects, like decreased lung capacity 

and function. Individuals experiencing shortness of breath, tightness in the chest or other 

problems breathing should seek immediate medical attention. 

Protective Measures. In workplaces where individuals handle diisocyanates or 

coatings or other formulations that contain them, an industrial hygiene and safety 

program should be operative. Important components of this program include: 

hazard communication and training on safe handling practices; use of efficient 

and well-maintained application equipment, engineering controls and personal 

protective equipment; housekeeping procedures including spill prevention and 

cleanup practices; and, if feasible, means to measure airborne levels of 

polyisocyanates and diisocyanates. 

During spray applications, workers should take precautions to avoid breathing vapors, mists or 

aerosols. Inhalation exposures should be limited to <0.05 mg/m3

 as an 8-hour time-weighted 

78

average (TWA) for combined polyisocyanates and diisocyanates.1 Engineering controls should 

serve as the first, most effective means of reducing airborne polyisocyanate and diisocyanate 

concentrations; an appropriate NIOSH/MSHA-approved respirator should be used as a 

secondary tool to lower exposures. Currently, downdraft spray booths and high-volume lowpressure (HVLP) spray guns appear to offer the most efficient technology to reduce inhalation 

exposures; a maintenance program should always be used to ensure optimal operating 

efficiencies. To limit dermal contact, individuals should wear impermeable gloves, protective 

clothing and goggles or glasses with side shields. 

May 1990, revised July 1993, February 1995, and February, 1997 

1

0.05 mg/m3 or 0.005 ppm TWA is the American Conference of Government Industrial 

Hygienists (ACGIH) Threshold Limit Value (TLV) for each hexamethylene diisocyanate (HMDI), 

toluene-2,4-diisocyanate (TDI), and methylene bisphenyl isocyanate (MDI). Also, OSHA has set 

0.02 ppm as exposure ceilings for both TDI and MDI. 

79

Category: $-Naphthylamines, Sulfonated Human Health 

Definition: Any new chemical whose structure is consistent with the following general structure 

is considered to be a member of the category of monosulfonated $-naphthylamines: 

Included in the category are azo dyes which release a sulfonated $-naphthylamine upon 

reduction of azo bonds. Also included in the category are N-acetylated sulfonated $­

naphthylamines. 

Hazard Concerns. Based on analogy to $-naphthylamine per se, members of the class are 

considered potential carcinogens. A number of mono- and disulfonated $-naphthylamines are 

positive in the Ames assay, and some are active in the mouse lung adenoma assay. The presence 

of one or two sulfonate groups or the sulfatoethylsulfone group is likely to slow systemic uptake 

and enhance excretion, however, the extent of these mitigating effects is unknown. 

Boundaries. Concern is restricted to sulfonated $-naphthylamines where not more than two 

sulfonate or sulfatoethylsulfone group(s) are on the ring distal to the $-amino group. The 

Agency has sufficient data to indicate that $-naphthylamines where a sulfonate group is on the 

proximal ring are unlikely to be carcinogenic. 

General Testing Strategy. 

The New Chemicals Program considers the following tests to be the most appropriate for monoand di-sulfonated $-naphthylamines found to pose an unreasonable risk: 

- An Ames test or, for azo dyes, an Ames test with the Prival modification, and 

- An unscheduled DNA synthesis test in rat hepatocytes. For azo dyes, it is necessary 

that the specific sulfonated $-naphthylamine in question be isolated prior to testing. 

For both tests, $-naphthylamine is to serve as an additional positive control. 

If the results of the genotoxicity testing indicate that the new chemical is genotoxic, a 

80

two- year, two-species cancer bioassay would be required. 

April 1991, updated June 1999 

81

------------------------------------

------------------------------------

------------------------------------

Category: Lanthanides or Rare Earth Metals Environmental Toxicity 

Definition. This category includes inorganic salts, complexes organic acids, and organometallic 

compounds or lanthanides or rare earth metals. There are 14 naturally-occurring lanthanides or 

rare earth metals: 

Name Symbol MW CASRN 

Lanthanum La 139 [7439-91-0] 

Cerium Ce 140 [7440-45-1] 

Praseodymium Pr 141 [7440-10-0] 

Neodymium Nd 144 [7440-00-8] 

Samarium Sm 150 [7440-19-9] 

Europium Eu 152 [7440-53-1] 

Gadolinium Gd 157 [7440-54-2] 

Terbium Tb 159 [7440-27-9] 

Dysprosium Dy 163 [7429-91-6] 

Holmium Ho 165 [7440-60-0] 

Erbium Er 167 [7440-52-0] 

Thulium Tm 169 [7440-30-4] 

Ytterbium Yb 173 [7440-64-4] 

Lutetium Lu 175 [7439-94-3] 

The lanthanide rare earth metals are very similar to each other. Their most important oxidation 

state is +3 for all. None are known to be essential to biological species. Across the lanthanide 

series from La to Lu, there is a general or steady decrease in their (1) atomic radii, (2) covalent 

radii, and (3) radii of their tripositve ions due to the addition of electrons at the 4f electron shell. 

This decrease in radii leads to a corresponding increase in the polarizing power of their ions and 

in the stability of complexes of their ions. They all have similar chemistry behaviors. 

Hazard Concerns. The only toxicity data available for the lanthanide series are for La [7439-

91-0]. Soluble salts of La are known to have high chronic toxicity towards fish, moderate 

chronic toxicity towards green algae, and low acute toxicity towards daphnids based on 

exposures in moderately hard water and in terms of mg La/L. Toxicity information are only 

available for La trichloride [10099-58-8] and La triacetate [917-70-4]. The toxicity profile for 

La based on available toxicity data, i.e., measured (M) and predicted (P), mg La/L (ppm La), and 

moderate hardness (i.e., <180.0 mg/L as CaCO3) is: 

82

fish 96-h LC50 < 1.0 P ACR10 

daphnid 48-h LC50 = 160.0 M S,N BK59 

green algal 96-h EC50 < 1.0 P EC50/ChV=4 

fish chronic value(ChV) = 0.020 M SR12,M H104 B78 

daphnid ChV = 20.0 P ACR10 

algal ChV = 0.150 M S,N BK59 

The lanthanides are assumed to be more toxic in soft water than hard water based on data for 

other heavy metals. 

Boundaries. The toxicity of the lanthanide rare earth metals depends on the their 

physical/chemical properties and the hardness of receiving waters. The toxicity of their salts and 

their complexes with organic acids are expected to be related to their water solubility, their 

MWs, and the stability of their complexes. The toxicity of lanthanide organometallic 

compounds, if they exist, are expected to be related to their octanol/water partition coefficient 

(Kow). 

The most important property determining the toxicity of chemicals derived from lanthanide rare 

earth metals is their water solubility. Water solubility cannot be estimated accurately and has to 

be measured. The water solubility of organometallic compounds is expected to decrease as Kow 

increases. There is no lower bound for Kow and the upper bound cannot be determined at this 

time since the Kow fragment-constant for any of the lanthanide rare earth metals are not known. 

In addition to solubility, MW is also an important boundary. Highly stable complexes and 

organometallics with MWs > 1000 are not expected to be absorbed by aquatic organisms even if 

they are water soluble. Therefore, only lanthanide rare earth metal-compounds with MWs < 

1000 are expected to be toxic. 

General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (40 CFR §797.1400 or OPPTS 850.1075) and 

daphnids (40 CFR §797.1300 or OPPTS 850.1010) will be done using the flow-through method; 

effective concentrations will be based on 100% active ingredients (ai) and mean measured 

concentrations; the total organic carbon (TOC) concentration of dilution water in the control 

must be less than 2.0 mg TOC/L; TOC must be measured in the control just prior to the start of 

the test; the highest treatment concentration on a nominal-basis should not exceed the aqueous 

solubility limit of the tested compound; solvent can be used to assist the compound to reach its 

aqueous solubility limit quicker, but cannot be used to artificially enhance the water solubility of 

the compound beyond its aqueous solubility limit; and hardness of dilution water has to be less 

than 180.0 mg/L as CaCO3. If toxicity mitigation testing is done with humic acid, then the static 

method with nominal concentrations will be recommended. 

83

The algal toxicity testing (40 CFR §797.1050 or OPPTS 850.5400), should be done with 

the static method; effective concentrations based on 100% ai and mean measured 

concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 96 hours; test 

medium with no more than 0.300 mg/L EDTA as a final concentration; the TOC of the 

test/growth medium should be less than 2.0 mg TOC/L; TOC should be measured just prior to 

the start of the test; the highest treatment concentration on a nominal-basis should not exceed 

the aqueous solubility limit of the tested compound; and solvent can be used to assist the 

compound to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance 

the water solubility of the compound beyond its aqueous solubility limit. If toxicity mitigation 

testing is done with humic acid, then nominal concentrations will be recommended. 

If there is no significant risk from the chemical after the results of the environmental base 

set have been integrated into the risk assessment, then no further testing will be recommended. 

However, if there is a significant risk, then go to Tier 2. 

Tier 2. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR §797.1600 or OPPTS 850.1400), with the flow-through method; effective concentrations 

based on 100% ai and mean measured concentrations; statistical analysis of effective 

concentrations at days 7, 14, 21, and 28; the TOC of dilution water in the control should be less 

than 2.0 mg TOC/L; TOC should be measured in the controls just prior to and during the test; 

the highest treatment concentration on a nominal-basis should not exceed the aqueous solubility 

limit of the tested compound; solvent can be used to assist the compound to reach its aqueous 

solubility limit quicker, but cannot be used to artificially enhance the water solubility of the 

compound beyond its aqueous solubility limit; and hardness of dilution water has to be less than 

180.0 mg/L as CaCO3. 

Daphnid chronic toxicity testing (40 CFR §797.1330 or OPPTS 850.1300), with the flowthrough method; effective concentrations based on 100% AI and mean measured concentrations; 

statistical analysis of effective concentrations at days 7, 14, and 21; the TOC of dilution water in 

the control should not exceed 2.0 mg TOC/L; TOC must be measured in the controls just prior 

to and during the test; the highest treatment concentration on a nominal-basis should not exceed 

the aqueous solubility limit of the tested compound; solvent can be used to assist the compound 

to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the water 

solubility of the compound beyond its aqueous solubility limit; and hardness of dilution water 

has to be less than 180.0 mg/L as CaCO3. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity tests 

will be recommended for terrestrial exposures. The terrestrial base set includes: the early 

seeding growth test (OPPTS 850.4230), the earthworm toxicity test (OPPTS 850.6200), the soil 

microbial community bioassay (OPPTS 850.5100), and the avian acute oral toxicity test (OPPTS 

850.2100). Chronic toxicity testing for terrestrial organisms include: the plant whole life cycle 

test (OPPTS 850.4150), the plant uptake test (OPPTS 850.4800), and the avian reproduction test 

(OPPTS 850.2300 for bobwhite quail or for mallard duck). 

84

February, 1998 

85

Category: Neutral Organics Environmental Toxicity 

Definition. This broad category includes non-reactive non-ionizable organic chemicals such as 

alcohols, ketones, ethers, alkyl halides, aryl halides, and aromatic hydrocarbons. 

Hazard Concerns. Neutral organics are environmentally toxic because of their ability to 

produce simple narcosis in aquatic species. Toxicity is a function of the octanol-water partition 

coefficient. Compounds with log P's of <5 exhibit toxicity within 96 hours. At log P 5-8, 

toxicity is apparent only after extended exposure. Compounds with a log P >8 are not toxic at 

water saturation even after prolonged exposure. There are a number of QSARs (quantitative 

structure-activity relationships) to predict the toxicity of neutral organics. 

Boundaries. The molecular weights of neutral organics of concern are generally less than 

1,000. Log P is <8. QSAR predictions of toxicity are constrained by water solubility. If a 

predicted toxicity level exceeds water saturation, then a longer test is needed to observe toxicity. 

General Testing Strategy 

To address ecotoxicity concerns, base set acute aquatic toxicity testing (algae (40 CFR 

797.1050): static method, daphnid (40 CFR 797.1300) and fish (40 CFR 797.1400): flowthrough method, all measured concentrations). 

86

To properly assess any human and environmental toxicity or exposure, certain 

environmental fate properties, such as aerobic biodegradation, need to be measured. Aerobic 

biodegradability can be determined using one of the following test guidelines, listed in 

approximate order of preference: 

Aerobic aquatic biodegradation

Modified Sturm test

Closed bottle test

Modified OECD screening test

Modified MITI test (I)

Modified AFNOR test

40 CFR 796.3100 

40 CFR 796.3260 

40 CFR 796.3200 

40 CFR 796.3240 

40 CFR 796.3220 

40 CFR 796.3180 

The physical state and electronic charge of the PMN substance should also be reported. 

For some neutral organics (e.g. ketones) direct/indirect photolysis (40 CFR 796.3765 and 

796.3700) AND possibly biodegradation testing is recommended. 

For some neutral organics (e.g. alkyl halides) hydrolysis testing (40 CFR 796.3510) AND 

possibly biodegradation testing is recommended. 

September 1988; revised October 1995 

87

Category: Nickel Compounds Human Health 

Environmental Toxicity 

Definition. Inorganic and organic compounds of nickel in which there is the potential for uptake 

of either Ni2+ or organonickel. 

Hazard Concerns. Nickel compounds e.g., nickel refinery dust, and its major component nickel 

subsulfide, have been shown to be carcinogenic in humans. Some nickel compounds are known 

to be genotoxic. IRIS has established an oral RfD for the soluble salts of nickel of 2 x 10-2 

mg/kg/d (1992) based on effects on organ weights in a two-year feeding study in rats. In the 

study, there was a statistically significant reduction in total body weight, higher heart-to-body 

weight ratios and lower liver-to-body weight ratios than controls. In addition to the effects on 

organ weights found in the critical two-year study, two other sensitive endpoints exist, neonatal 

mortality and dermatotoxicity. While no reproductive effects have been associated with nickel 

exposure to humans, several studies in laboratory animals have demonstrated fetotoxicity. 

Soluble inorganic nickel compounds produce acute and chronic toxicity in freshwater and 

saltwater aquatic organisms over a wide range of concentrations but bioconcentrates only to a 

small degree. There are no known toxicity data for organonickel compounds. 

Boundaries. Any nickel compound that will release Ni2+ is considered hazardous. Conversely, 

there are no available data to suggest that nickel compounds in which the Ni2+ is not released 

may pose a health hazard. 

The boundaries for ecotoxicity of Ni2+ compounds depend on whether they are Ni2+ salts, 

Ni2+ chelates, or organonickel compounds. There is also a molecular weight boundary for strong 

ion pairs/complexes which is 1000. 

The boundaries for organonickel compounds (e.g., Kow

undefined but the molecular weight boundary is expected to be 1000. 

of the organic portion) are 

Occupational Exposure Controls. Because nickel compounds have been shown to be toxic by 

the inhalation/ingestion route, exposure controls that maintain airborne exposures at 0.1 mg/m3 

or below are needed (consistent with OSHA PEL TWA). In addition, since nickel compounds 

are also toxic by the dermal route, NIOSH approved protective gloves are also recommended. 

Testing. Depending upon estimated workplace exposures and releases to water, which will 

be assessed on a case-by-case basis, the following testing may be recommended: 

To address health effects concerns due to the toxicity of nickel and its compounds, the 

following tests may be recommended: 

A 90-day subchronic study in rats by an appropriate route to assess systemic toxicity 

(OPPTS 870.3100 or 870.3250 or 870.3465) 

88

Results of the 90-day study may trigger a lifetime bioassay in rats and mice by the 

inhalation route to assess potential carcinogenicity (OPPTS 870.4200) 

To address ecotoxicity concerns due to toxicity of nickel and its compounds, the 

following base set tests may be recommended: 

Acute fish toxicity test OPPTS 850.1075 

Acute daphnid toxicity test OPPTS 850.1010 

Green algae toxicity test OPPTS 850.5400 

All tests utilize measured concentrations. 

To properly assess human and environmental toxicity or exposure, certain physicochemical or environmental fate properties need to be measured: 

Water solubility 

Octanol/water partition coefficient (Kow )

Vapor pressure

Melting point-melting range

Boiling point

OPPTS 830.7840 or 830.7860

OPPTS 830.7550 or 830.7560 or 830.7570

OPPTS 830.7950 or 830.8000

OPPTS 830.7200

OPPTS 830.7220

In addition, aerobic biodegradation by one of the following methods: 

CO2 evolution

Closed bottle

Modified OECD screening

Modified MITI (I)

DOC die-away

Manometric respirometry

References. 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

IRIS access. # 1271 (09/30/87) Nickel, soluble salts. 

OSHA PELs (1995-1996) 

September 1996 

89

Category: Nonionic Surfactants Environmental Toxicity 

Definition. Any neutral structure having surfactant activity is considered a member of this 

category. Many of these surfactants have the following types of structure: 

Ethoxylate groups may be mixed with or be replaced by alcohol groups. Other neutral groups 

e.g. propoxylates, esters, halogens, may also be present. 

Hazard Concerns. Acute aquatic toxicity increases exponentially with increases in the 

hydrophobic chain length when the number of ethoxy groups or the hydrophilic component is 

held constant. In addition, when the number of carbons in the hydrophobe are constant, toxicity 

decreases with an increasing number of ethoxylate groups. The aquatic toxicity of members of 

the category can be predicted by structure-activity relationship (SAR). 

Boundaries. There are no established molecular weight boundaries for this category. Limits on 

chain length are inherent in the SARs. 

Testing. To address ecotoxicity concerns, base set acute aquatic toxicity testing (algae: static 

method, daphnid and fish: flow-through method, all measured concentrations). 

Tier 1. The acute aquatic base set of environmental toxicity tests will be recommended 

for aquatic exposures and the terrestrial base set of environmental toxicity tests (i.e., the early 

seeding growth test, the earthworm acute toxicity test and the soil microbial community 

bioassay) will be recommended for any terrestrial exposures. 

Acute fish toxicity test

Acute daphnid toxicity test

Green algae toxicity test

Early seedling growth test

Earthworm acute toxicity test

Soil microbial community bioassay

OPPTS 850.1075 

OPPTS 850.1010 

OPPTS 850.5400 

OPPTS 850.4230 

OPPTS 850.6200 

OPPTS 850.5100 

Tier 2. If acute toxicity testing indicates a significant risk, then environmental fate 

testing in the form of aerobic biodegradation testing is recommended. Aerobic biodegradability 

can be determined using one of the following test guidelines: 

90

CO2 evolution OPPTS 835.3110 

Closed bottle OPPTS 835.3110 

Modified OECD screening OPPTS 835.3110 

Modified MITI (I) OPPTS 835.3110 

DOC die-away OPPTS 835.3110 

Manometric respirometry OPPTS 835.3110 

Tier 3. In addition, if acute toxicity testing indicates a significant risk, then chronic 

aquatic toxicity testing with fish and aquatic invertebrates will be recommended. 

Fish early life stage test OPPTS 850.1400 

Daphnid chronic toxicity testing OPPTS 850.1300 

September 1988, revised September 1996 

91

Category: Organotins Human Health 

Environmental Toxicity 

Definition. This category includes all mono-, di-, tri- and tetra-alkyl or phenyl organotin 

compounds, including organotin esters/oxides. The mode of toxic action of organotins in 

humans is unknown, but they are known to affect carbonate metabolism and other metabolic 

processes in the brain, liver, and muscle, as well as several enzymes and the oxidative activity of 

mitochondria. It has been suggested that general sulfhydryl binding may be responsible for the 

effects seen in mammals. It is assumed that these compounds need to be absorbed to be toxic, 

therefore, compounds with MWs > 1000 and which do not transform to organotin compounds 

with MWs < 1000 will be excluded from this category. Human health and aquatic toxicity for 

liquid organotins is assumed to be limited by the relative octanol/water partition coefficient (a 

relative Kow is based on the computer program, CLOGP, with C substituted for Sn). However, 

the limiting relative Kow value is unknown. The Agency has data for an organotin with a relative 

log Kow = 13.7 which still showed high toxicity towards fish and daphnids. Organotins which 

are solids at room temperature may show no toxicity at saturation at log Kow values < 13.7 

depending on the melting point, i.e., the higher the melting point at a given Kow, the greater the 

likelihood that no toxicity will be observed at saturation. For solids, the no-effects-at-saturation 

determination has to be made on a case-by-case basis. There are no known Kow limits for acute 

and chronic environmental toxicity at this time, but it is higher than a log Kow = 13.7. Future 

testing will determine 

the Kow limits. 

Hazard Concerns. Tested organotins have been shown to be from moderately irritating to 

corrosive to the skin and eyes. Acute oral and dermal exposures can result in systemic effects, 

primarily neurotoxicity. Concerns for immunotoxicity are based on data on dialkyltins and 

trialkyltins. During a 13-week oral study in rats using dioctyltin bis (2-ethylhexylthioglycolate), 

effects to the thymus, spleen, lymph nodes, and bone marrow were observed. A No-ObservableAdverse-Effect-Level (NOAEL) of 1.6 mg/kg/d was derived from this study. During a 17-month 

feeding study in rats using bis (tri-n-butyltin)-oxide, immunoglobulin E (IgE) titers were 

reduced, as well as the activity of natural killer cells in the spleen, and there was reduced 

macrophage function. A NOAEL of 0.025 mg/kg/d was derived from this study. Based on the 

immunotoxicity end-point, an oral reference dose for chronic exposure (RfD) for tributyltin 

92

oxide of 3 x 10-5 mg/kg/d (IRIS 01/01/89) has been derived. Organotins are well known 

neurotoxins, with the tri- and tetra-substituted tins being more toxic than the mono- and disubstituted compounds. Although many tri-alkyltins show clear neurotoxic effects (eg. lesions in 

the hippocampus), the neurotoxic potential of di-alkyltins has not been as well defined. 

Available data indicate that dibutyltin and dioctyltin can produce neurotoxic effects such as 

reductions in brain neurotransmitter levels, alterations in spontaneous motor activity and 

hindlimb weakness. An effect level for neurochemical and behavioral changes following 3 days 

of oral administration of dibutyltin dilaurate was reported as 20 mg/kg. There are oncogenicity 

concerns for some of the organotins based on analogy to triphenyltin hydroxide, a group B 

probable human carcinogen. Therefore, the human health concerns for phenyltins will be dealt 

with on a case-by-case basis. 

The acute aquatic toxicity for several subclasses of organotins has been determined through 

toxicity testing (Vighi & Calamari, 1985; Wong et al. 1982) and structure activity relationships 

(SAR). Organotins have been shown to be highly toxic to green algae (Wong et al. 1982). The 

acute toxicity of organotins is moderate to high towards daphnids (Vighi & Calamari, 1985). 

One datum for fish has indicated high toxicity (USEPA 1996). Organotins exhibit toxicity 

ranging from moderate toxicity (i.e., > 10 mg/L) to high toxicity (i.e., < 1 mg/L) depending on 

their Kow , melting point, and MW. The higher the Kow, the higher the toxicity (or the lower the 

EC50 value). 

Boundaries. There are no known boundaries. The upper boundaries will be based on Kow and 

MW. Acute toxicity expected with log Kow < 13.7; chronic toxicity has no known upper bound 

for log Kow, but it is > 13.7. MW will be < 1000 for stable compounds. The environmental base 

set of tests will be requested for aquatic releases and the terrestrial base set of tests will be 

recommended for terrestrial exposures. 

General Testing Strategy. 

TIER 1. 

A 90-day subchronic test in rodents by the oral route with special attention to the lymphoid 

organs (thymus, spleen, peripheral lymph nodes) and bone marrow (OPPTS 870.3100). 

Neurotoxicity testing to include motor activity, a functional observational battery and 

neuropathology with special attention to lesions in the hippocampus (OPPTS 870.6200). This 

testing can be combined with the 90-day subchronic protocol cited above. 

The acute aquatic base set of environmental toxicity tests will be recommended for aquatic 

exposures and the terrestrial base set of environmental toxicity tests will be recommended for 

terrestrial exposures. The acute toxicity tests for fish and daphnids should be done using the 

flow-through method with measured concentrations. Effective concentrations should be based 

on 100% active ingredients (AI) and mean measured concentrations. Measure TOC of dilution 

water in the control just prior to testing. Ideally, the highest treatment concentration on a mean 

93

measured concentration-basis should equal the aqueous solubility limit. Solvent can be used to 

assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to significantly 

enhance the water solubility. The algal toxicity testing should be done with the static method 

and measured concentrations. Statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours should be performed. The test medium should be used with at least 0.300 mg/L EDTA 

as a final concentration. 

Aquatic Base Set

Acute fish toxicity test

Acute daphnid toxicity test

Green algae toxicity test

Terrestrial Base Set

Early seedling growth test

Earthworm acute toxicity test

Soil microbial community bioassay

TIER 2. 

OPPTS 850.1075 

OPPTS 850.1010 

OPPTS 850.5400 

OPPTS 850.4230 

OPPTS 850.6200 

OPPTS 850.5100 

If acute aquatic toxicity testing indicates a significant risk, the following environmental fate 

testing is recommended to determine aerobic biodegradability using one of the following test 

guidelines: 

CO2 evolution

Closed bottle

Modified OECD screening

Modified MITI (I)

DOC die-away

Manometric respirometry

TIER 3. 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

OPPTS 835.3110 

If acute toxicity testing and environmental fate testing continue to indicate a significant risk, then 

chronic aquatic toxicity testing with fish and aquatic invertebrates is recommended with flowthrough methods and measured concentrations. Effective concentrations should be based on 

100% active ingredients (AI) and mean measured concentrations. Conduct statistical analysis of 

effective concentrations at days 7, 14, 21, and 28. Measure TOC of dilution water in the control 

just prior to testing. Ideally, the highest treatment concentration on a mean measured 

concentration-basis should be equal at the aqueous solubility limit. Solvent can be used to assist 

the PMN to reach its aqueous solubility limit quicker, but cannot be used to significantly 

enhance the water solubility. The 7-d fish early life stage (ELS) toxicity test cannot be 

substituted for the 28-d ELS toxicity test and the 7-d daphnid chronic toxicity test cannot be 

substituted for the 21-d toxicity test because Van Leeuwen et al. (1990) have demonstrated that 

the 7-d ELS toxicity test underestimated the chronic toxicity of anilines measured by the 28-d 

94

ELS toxicity test by >5.3 times when the NOECs were compared (see Table VII in Van 

Leeuwen). 

Chronic Aquatic Toxicity

Fish early life stage test OPPTS 850.1400

Daphnid chronic toxicity testing OPPTS 850.1300

References. 

8E-594. 

Tributyltin oxide. Bis-(tri-n-butyltin)-oxide. (1988, December). Gesellschaft Deutscher 

Chemiker - Advisory Committee on Existing Chemical of Environmental Relevance 

(BUA). BUA Report 36. 

USEPA 1996. United States Environmental Protection Agency (1996). The Office of Pollution 

Prevention andToxics (OPPT) premanufacture notification (PMN) ECOTOX database: a 

confidential business information (CBI) collection of environmental toxicity data from 

new chemical submissions under Sec. 5 of the Toxic Substances Control Act (TSCA). 

Washington, DC: Environmental Effects Branch, Health and Environmental Review 

Division (7403), OPPT, USEPA. OPPT contact is V. Nabholz, 202-260-1271. 

Van Leeuwen, C.J., Adema, D.M.M., & Hermens, J. (1990). Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology, 16, 321-334. 

Vighi, M., & Calamari, D. (1985). QSARs for organotin compounds on Daphnia magna. 

Chemosphere, 14, 1925-1932. 

WHO 1980. World Health Organization Environmental Health Criteria 15. Tin and organotin 

compounds: A preliminary review. Geneva: WHO pp. 59-62. 

Wong, P.T.S., Chau, Y.K., Kramar, O., & Bengert, G.A. (1982). Structure-toxicity relationship 

of tin compounds on algae. Canadian Journal of Fisheries and Aquatic Sciences, 39, 

483-488. 

April 1991, revised September 1996 

95

Category: Peroxides Human Health (case-by-case) 

Environmental Toxicity 

Definition. Any molecular structure containing one or more of the following functional groups 

is considered to be a member of the class: 

| |


-C-O-O-C­


| |


| 


-C-O-O-H


| 


O 

5 | 

-C-O-O-C­


|


O O


5 5

-C-O-O-C-


O


5

-C-O-O-H 


dialkyl peroxide 

alkyl hydroperoxide 

peroxy ester 

diacyl peroxide 

peroxy acid 

The category of peroxides is a small one (<0.2% of all new chemicals). The "typical" peroxide 

in the new chemical program is a discrete (class I) chemical with a molecular weight of <500. 

Hazard Concerns. EPA had previously identified hazard concerns for the possible 

carcinogenicity of new chemicals falling into the peroxide category based on available evidence. 

EPA has reviewed test data developed by the Society of the Plastics Industry (SPI) and others on 

the peroxide category of chemicals and concludes that available information does not support 

continued identification of peroxides as a new chemical category presenting concerns for 

possible carcinogenicity. EPA will continue to evaluate the potential health concerns for new 

chemical peroxides that are notified but, with this change, will not apply a category 

understanding as regards potential carcinogenicity. While the assessment of potential human 

health hazard concerns will be conducted on a case-by-case basis, this modification does not 

affect EPA’s approach to environmental hazard concerns which will continue to be identified for 

members of this category. 

Boundaries. There are no established boundary conditions for review of peroxides. 

General Testing Strategy. 

96

The New Chemicals Program considers the following tests to be appropriate to address 

ecotoxicity concerns for peroxides: 

1. Base-set ecotoxicity testing to include fish (40 CFR 797.1400), daphnids (40 CFR 

797.1300), and algae (40 CFR 797.1050). 

2. Environmental fate testing including, as appropriate, melting point (40 CFR 796.1300) or 

boiling point (40 CFR 796.1220), water solubility (40 CFR 796.1840 or 796.1860), log Kow (40 

CFR 796.1550, 796.1570, or 796.1720), vapor pressure (40 CFR 796.1950), hydrolysis (40 CFR 

796.3500), direct and indirect photolysis (40 CFR 796.3765), and aerobic biodegradation by any 

of the following test guidelinesModified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

September, 1988; revised June, 1994; revised April, 2001 

97

Category: Persistent, Bioaccumulative, 

Environmental Fate 

and Toxic (PBT) Chemicals Health/Environmental Toxicity 

Definition. PBT chemical substances possess characteristics of persistence (P) in the 

environment, accumulation in biological organisms (bioaccumulation (B)), and toxicity (T) that 

make them priority pollutants and potential risks to humans and ecosystems. Prominent 

examples of PBT chemical substances include the insecticide, DDT and polychlorinated 

biphenyls (PCBs). This PBT category includes the boundary conditions, such as fish 

bioconcentration/bioaccumulation factors and environmental persistence values, that would 

determine inclusion in (or exclusion from) the category, and standard hazard and fate tests to 

address P, B, and T concerns for the chemical substances fitting the category description. For 

background information and discussion of this PBT category, see 

http://www.epa.gov/oppt/newchems/pbtpolcy.htm, and the proposed (October 5, 1998; 63 FR 

53417) and final (November 4, 1999; 64 FR 60194) “Category for Persistent, Bioaccumulative, 

and Toxic Chemical Substances” published in the US Federal Register. 

Hazard Concerns. Generally, PBT chemical substances are chemical substances that partition 

to water, sediment or soil and are not removed at rates adequate to prevent their bioaccumulation 

in aquatic or terrestrial species, with the potential to pose a risk via food chain toxicity. 

Boundaries. The following table summarizes specific identification criteria and associated 

process for use in evaluating new chemical PBT substances. 

NEW CHEMICALS PROGRAM 

PBT CATEGORY CRITERIA AND PROCESS 

TSCA Section 5 Action 

5(e) Order/Significant New 

Use Rule (SNUR) 

Exposure/release controls 

included in order; testing 

required 

Ban Pending Testing 

Deny commercialization; testing results 

may justify removing chemical from “high 

risk concern” 

Persistence 

(transformation half-life) 

>2 months >6 months 

Bioaccumulation* 

(Fish BCF or BAF) 

>1000 >5000 

Toxicity Develop toxicity data where necessary, based upon various 

factors, including concerns for P, B, other physical/chemical 

factors, and toxicity. 

*Chemicals must also meet criteria for MW (<1000) and cross-sectional diameter (<20D, or <20 x 10 -8 cm). BCF 

of 1000 and 5000 are equivalent to log Kow of 4.2 and 5, respectively. 

98

General Testing Strategy 

Tier 1. Based upon SAR and professional judgment, the Agency identifies a new chemical 

substance as a possible PBT chemical substance. 

Log Kow Liquid chromatography (OPPTS 830.7570/OECD 117) or 

generator column (OPPTS 830.7560) method 

Ready biodegradability Ready biodegradability (OPPTS 835.3110/OECD 301) 6 

methods (choose one, or an equivalent test): DOC DieAway, CO2 Evolution, Modified MITI (I), Closed Bottle, 

Modified OECD Screening, Manometric Respirometry 

or 

Sealed-vessel CO2 production test (OPPTS 835.3120) 

Hydrolysis in water (if, 

based upon SAR, 

susceptibility to hydrolysis is 

suspected) 

OPPTS 835.2110 (OECD 111) 

Results If the measured log Kow is <4.2 or if the test chemical 

passes the ready biodegradability test (i.e., not persistent in 

the environment), no further PBT-related testing is required. 

If the measured log Kow is greater than or equal to 4.2 and 

the chemical does not pass the ready biodegradability test, 

the chemical would require tier 2 testing. If hydrolysis 

testing is conducted and results in a half-life of <60 days, 

further testing may not be needed, but the need for testing 

must be determined after consideration of factors specific to 

the case, such as physical/chemical properties, persistence 

and bioaccumulative qualities of hydrolysis products, and 

the nature of the expected releases. 

99

Tier 2. Biodegradability and Bioaccumulation 

Biodegradability Shake-flask die-away test (OPPTS 835.3170) or an 

equivalent test. 

Bioaccumulation Fish bioconcentration test (OPPTS 850.1730/OECD 305), or 

an equivalent test). Measured BCF should be based on 100 

percent active ingredient and measured concentration(s). 

Results If the measured biodegradation half-life is >60 days and 

measured BCF is >1000, tier 3 testing will be required. If 

only one condition is met, releases and exposure are further 

considered to determine if additional testing is required. 

Tier 3. Toxicity/advanced environmental fate testing. 

Human health toxicity Combined repeated dose oral toxicity with the 

reproductive/developmental toxicity screening test (OECD 

No. 422) in rats. Other health testing will be considered 

where appropriate. 

Environmental fate Sediment/water microcosm biodegradation test (OPPTS 

835.3180). 

Chronic environmental 

toxicity 

Fish (rainbow trout) and daphnids should be tested 

according to 40 CFR 797.1600 (same as OPPTS 

850.1400/OECD 210) and 40 CFR 797.1330 (same as 

OPPTS 850.1300/OECD 202), respectively. Additional 

testing to evaluate other biota (e.g., avian, sediment dwelling 

organisms) or other effects (e.g., endocrine disrupting 

potential) will be considered where appropriate. 

November, 1999 

100

Category: Phenolphthaleins Human Health 

Definition. Any chemical containing the phenolphthalein structure is considered to be a member 

of the category. 

Hazard Concerns. The health concern for phenolphthalein and derivatives of phenolphthalein 

is for cancer based on the NTP cancer study (NTP report TR-465, November 1996) for 

phenolphthalein with administration via the diet. There was clear evidence of carcinogenic 

activity in male F344/N rats based on markedly increased incidences of benign 

pheochromocytomas of the adrenal medulla and of renal tubule adenomas and adenomas or 

carcinomas (combined). There was some evidence of carcinogenic activity in female F344/N 

rats based on the increased incidences of benign pheochromocytomas of the adrenal medulla in 

the 12,000 ppm group and of benign or malignant pheochromocytomas (combined) in the 12,000 

and 25,000 ppm groups. There was clear evidence of carcinogenic activity in male B6C3F1 mice 

based on increased incidences of histiocytic sarcomas and of malignant lymphomas of thymic 

origin. There was clear evidence of carcinogenic activity in female B6C3F1 mice based on 

increased incidences of histiocytic sarcomas, malignant lymphomas of all types, lymphomas of 

thymic origin, and benign sex-cord stromal tumors of the ovary. 

Boundaries. No boundaries currently defined. 

101

Testing. EPA considers the following tests to be the most appropriate for phenolphthalein 

derivatives found to pose an unreasonable risk to human health: 

Tier 1: 

Comparative dermal and oral absorption study in rats (OPPT Harmonized Test Guidelines, 

870.7485) 

in vitro Chromosome aberrations study in Chinese hamster ovary cells with phenolphthalein as 

an additional positive control (OPPT Harmonized Test Guidelines, 870.5375) 

Log Kow test (OPPTS 830.7550) 

Water solublility for both lactone and acid form (OECD 105) 

Ready biodegradability (OPPT 835.3110) 

Tier 2: 

2-year carcinogenicity study in mice (OPPT Harmonized Test Guidelines, 870.4200) 

April, 1998 

102

Category: Phenols Environmental Toxicity 

Definition. This category includes phenols (i.e., monophenols), polyhydroxy phenols, and 

polyphenols. It is assumed that these compounds need to be absorbed to be toxic, therefore, 

compounds with MWs > 1000 will be excluded from this category. Acute toxicity for phenols 

which are liquids at room temperature is known to be limited by the octanol/water partition 

coefficient (Kow). Above a log Kow value of about 7.38, phenols are expected to show no effects 

at saturation during 96-h exposures (Veith and Broderius 1987). Phenols which are solids at 

room temperature may show no toxicity at saturation at lower Kow values depending on the 

melting point, i.e., the higher the melting point at a given Kow, the greater the likelihood that no 

toxicity will be observed at saturation. For solids, no effects at saturation has to be demonstrated 

on a case-by-case basis. There are no known Kow limits for chronic toxicity at this time, but it 

may not be much above a log Kow = 9.0 for liquid phenols. Future testing will determine this Kow 

limit. 

Hazard Concerns. The acute and chronic toxicity for phenols can be predicted through SAR 

Analysis. SARs are available for fish 96-h LC50, daphnid 48-h LC50, green algal 96-h EC50, 

fish chronic value (ChV), daphnid ChV, and algal ChV. Members of this category exhibit 

toxicity ranging from low toxicity (i.e., > 100 mg/L) to high toxicity (i.e., < 1 mg/L) depending 

on their Kow, MW, and substitutions (e.g., dinitrophenols). 

Dinitrophenols are known to be more toxic than predicted by these SARs (see the 

category for polynitroaromatics). 

Fate: Phenols are subject to indirect photolysis under environmentally realistic conditions. 

Boundaries. There are no known lower boundaries. The upper boundaries will be based on Kow 

and MW. Acute toxicity expected with log Kow < 7.38; no effects at saturation during 96-h 

exposures when log Kow >= 7.38. Chronic toxicity has no known upper bound for log Kow, but it 

is probably near 9. MW will be < 1000. The environmental base set of tests will be requested 

for aquatic releases and the terrestrial base set of tests will be recommended for terrestrial 

exposures. When the log Kow is >= 7.38, chronic toxicity testing with fish, daphnids, and green 

algae will be recommended. 

General Testing Strategy 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (40 CFR 797.1400) and daphnids (40 CFR 

797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; the highest treatment 

concentration on a nominal-basis should equal the aqueous solubility limit; and solvent can be 

103

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

The algal toxicity testing (40 CFR 797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% AI and mean measured 

concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 96 hours; test 

medium with at least 0.300 mg/L EDTA as a final concentration; the highest treatment 

concentration on a nominal-basis equal to the aqueous solubility limit; and solvent can be used 

to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially 

enhance the water solubility of the PMN beyond its aqueous solubility limit. 

If there is no significant risk from the PMN after the results of the environmental base set 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 2. 

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, go to Tier 4. 

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40.796.3765 (b)(2) and (c)(2)], expose to sunlight 

for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive species 

from environmental base set. For example, the most sensitive species from the environmental 

base set has an EC50 value = 2.0 mg PMN/L (based on 100% AI, therefore, prepare a 5.0 mg 

PMN per liter stock solution based on 100% AI using the standard humic-containing solution. 

This stock solution is exposed to sunlight for at least 6 half-lives to ensure that all of the PMN 

has been photolyzed, and then this stock solution is used to retest the most sensitive aquatic 

species to determine if the photolysis products of the PMN are more or less toxic that the PMN. 

Tier 4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR 797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% AI and mean measured concentrations; statistical analysis of effective 

concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the control; the 

highest treatment concentration on a nominal-basis should be set at the aqueous solubility limit; 

solvent can be used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be 

used to artificially enhance the water solubility of the PMN beyond its aqueous solubility limit; 

and the 7-d ELS stage toxicity test cannot be substituted for the 28-d ELS toxicity test because 

Van Leeuwen et al (1990) have demonstrated that the 7-d ELS toxicity test underestimated the 

chronic toxicity of anilines measured by the 28-d ELS toxicity test by >5.3 times when the 

NOECs were compared (see Table VII in Van Leeuwen); 

104

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% AI and mean measured 

concentrations; statistical analysis of effective concentrations at days 7, 14, and 21; measured 

TOC of dilution water in the control; the highest treatment concentration on a nominal-basis 

should be set at the aqueous solubility limit; solvent can be used to assist the PMN to reach its 

aqueous solubility limit quicker, but cannot be used to artificially enhance the water solubility of 

the PMN beyond its aqueous solubility limit; and the 7-d daphnid chronic toxicity test cannot be 

substituted for the 21-d toxicity test 

because Van Leeuwen et al (1990) have demonstrated that the fish 7-d ELS toxicity test 

underestimated the chronic toxicity of anilines measured by the fish 28-d ELS toxicity test by 

>5.3 times when the NOECs were compared (see Table VII in Van Leeuwen). 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test, the earthworm toxicity test and the soil microbial 

community bioassay) will be recommended for terrestrial exposures. Chronic toxicity testing 

for terrestrial organisms include: the plant whole life cycle test, the plant uptake test, and the 

soil microbial community bioassay. 

References. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

Veith GD and Broderius SJ. 1987. Structure-toxicity relationships for industrial chemicals 

causing type (II) narcosis syndrome. In Kaiser KLE (ed), QSAR In Environmental Toxicology -

II, p 385-391. Reidel Publishing Company. 

July, 1991 

105

Category: Phosphates, Inorganic 

Definition. This category includes all inorganic soluble forms of phosphates, such as,

phosphoric acid [PO4H3 or OP(=O)(O)O] and its salts or phosphate salts, pyrophosphates,

polyphosphates, and organic and inorganic forms of phosphorous that can be oxidized to

phosphates rapidly. Inorganic forms of phosphonic acid (H2PO3 or OP(=O)O) are not included

in this category because monopotassium phosphonic acid [13977-65-6] has been shown not to be

an algal nutrient, not to be a replacement for phosphate in algal growth medium, and not to cause

exponential growth of green algae.

Hazard Concerns. The standard environmental toxicity profile for inorganic phosphates as P in

mg P/L is:

ECOTOX: Predicted (P) and measured (M) toxicity values in mg/L (ppm) are:

fish 96-h LC50 > 100.0 P

daphnid 48-h LC50 > 100.0 P

green algal 96-h EC50 b < 0.030 P

algal 96-h EC290 b = 0.030 M S,N

fish chronic value > 10.0 P

daphnid ChV > 10.0 P

algal ChV = 0.010 M Hutchinson 1957

Predictions are based on SAR-nearest analog analysis for soluble forms of inorganic 

phosphates (PO4); SAR chemical class = P-O4; MW of P = 31, PO4 = 95, PO4H3 = 98; pH7; 

effective concentrations based on 100% active ingredients and nominal concentrations of P; 

hardness <24.0 mg/L as CaCO3; and TOC <2.0 mg/L; 

high concern for eutrophication; 

assessment factor = 10.0 

concern concentration = 0.001 

Phosphate phosphorus has the potential to stimulate the growth of green algae and cause 

algal blooms and eutrophication in freshwater and marine environments. The phosphate anion is 

a plant nutrient and is the major limiting nutrient in many freshwater environments. The USEPA 

OW WQC (USEPA 1976) states: 

[W]hen such concentrations [of total phosphate phosphorus]exceed 25 :g/l at the time of 

the spring turnover on a volume-weighted basis in lakes or reservoirs, they may occasionally 

stimulate excessive or nuisance growths of algae and other aquatic plants. Algal growths impart 

undesirable tastes and odors to water, interfere with water treatment, become aesthetically 

unpleasant and alter the chemistry of the water supply. The contribute to the phenomenon of 

cultural eutrophication. 

To prevent the development of biological nuisances and to control accelerated or cultural 

eutrophication, total phosphates as phosphorus (P) should not exceed 50 :g/l in any stream at the 

point where it enters any lake or reservoir, nor 25 :g/l within the lake or reservoir. A desired 

goal for the prevention of plant nuisances in streams or other flowing waters not discharging 

106

directly to lakes or impoundments is 100 :g/l total P (Mackenthum, 1973). Most relatively 

uncontaminated lake districts are known to have surface waters that contain from 10 micrograms 

P/L (or 31 micrograms PO4H3/L) to 30 microg P/L (or 92 microg PO4H3/L) (Hutchinson, 

1957). 

Odum (1971) called phosphorus a major factor in the process of cultural eutrophication. 

Eutrophication results when nutrients, especially phosphates, are imported into aquatic 

ecosystems. This process is analogous to fertilizing an agricultural field. Phosphates act like a 

fertilizer and produce increases in the abundance of algae and other aquatic plants; eventually, 

they can result in excessive growths of algae (i.e., algal blooms). Excessive algae can block 

sunlight from reaching submerged macrophytes and other microalgae below the surface. When 

the algae die and fall to the bottom of slow-moving water or lakes, they are consumed by 

bacteria which use up available oxygen producing anaerobic conditions. Decaying algae cause 

odors and oxygen depletion of the water to occur with concomitant detriment to fish and aquatic 

invertebrates and, in turn, fishing and water-based recreational activities. 

Phosphate concentrations as low as 0.050 mg P/L (ppm) or 50.0 micrograms P/L (ppb) 

will produce exponential growth of green algae in 96 hours (Miller et al. 1978), and phosphate 

concentrations from 10 to 60 micrograms P/L (ppb) were correlated to algal blooms and oxygen 

depletion (i.e., eutrophication) in Lake Washington, Seattle (Odum 1971). Phosphates have been 

severely limited or banned from detergents in 13 states, the District of Columbia, and several 

counties and municipalities (USEPA 1992). Sodium tripolyphosphate was one of the principal 

components of synthetic detergents. Freshwater green algae are clearly the most sensitive group 

of aquatic organisms to phosphate additions to water. 

Boundaries. The boundaries for inorganic phosphate compounds depend on the release of 

inorganic phosphates which can be used by algae as a mineral nutrient. Any inorganic phosphate 

which can be used by algae as a nutrient or which transforms to release or becomes an algal 

nutrient is included in this category. 

Testing. Based on a consideration of available data on inorganic phosphates and the 

physicochemical properties of these compounds, there is no need for further testing. However, if 

there is doubt about the availability of phosphate in a nutrient form from a PMN substance, then 

the algal toxicity test can be done with the PMN substance substituted for phosphate nutrient in 

the algal growth medium. If a PMN substance is capable of stimulating exponential growth 

green algae, it must be emphasized that inorganic phosphates should not be released to water 

because of their potential to cause eutrophication and their persistence. 

Regulatory Actions. 

(1) Phosphates have been severely limited or banned from detergents in 13 states, the District of 

Columbia, and several counties and municipalities (USEPA 1992). 

(2) Water Quality Criterion, 1976 (USEPA 1976): total phosphates as phosphorus (P) should 

not exceed 50 micrograms p/L in any stream at the point where it enters any lake or reservoir, 

nor 25 micrograms P/L within the lake or reservoir. 

107

(3) Hazard assessments of selected aqueous cleaner chemicals, USEPA (1990): OPPT 

recommendation to the Office of Air and Radiation: "...phosphates should never be released to 

water." 

(4) Agency recommendation for a "nationwide elimination of the use of household laundry 

detergents containing phosphates." (USEPA 1992). 

References. 

Hutchinson, G. E., 1957, A treatise on limnology. New York, NY: John Wiley & Sons. 

Mackenthun, K. M., 1973, Toward a cleaner aquatic environment. Washington, DC: USEPA. 

Miller, W. E., Greene, J. C., and Shiroyama T. 1978. The Selenastrum capricornutum Printz 

algal assay bottle test. Corvallis, OR: USEPA, Office of Research and Developmental, 

Environmental Research Laboratory-Corvallis, EPA-600-9-78-018. 

United States Environmental Protection Agency (USEPA). 1976. Quality Criteria for Water. 

EPA-440/9-76-023. Washington, DC: Office of Water Planning and Standards, OW, USEPA. 

Available from NTIS, Springfield, VA 22161, PB-263-943. 

United States Environmental Protection Agency (USEPA). 1990. (Health and environmental 

effects of selected aqueous cleaner chemicals. Washington, DC: Health and Environmental 

Review Division, Office of Pollution Prevention and Toxics, USEPA. 

United States Environmental Protection Agency (USEPA). 1992. (DRAFT Phosphate 

detergents: An evaluation of the benefits and costs of eliminating their use in the United States. 

Washington, DC: Environmental Results Branch, Office of Policy, Planning, & Evaluation, 

USEPA. 

March, 2000 

108

Category: Phosphinate Esters Environmental Toxicty 

Phosphinate esters are a class of organic compounds characterized by the functional 

group R-O-P(=O)(R)R. Phosphinate esters are metabolically active and exhibit excess aquatic 

toxicity in addition to narcosis. Phosphinate esters exhibit excess toxicity relative to simple 

esters (-C(=O)O-) and phosphate esters (-OP(=O)(O-)O-. 

It is assumed that phosphinate esters need to be absorbed to be toxic, therefore, 

phosphinate esters with MW >1000 will be excluded from this category. Acute toxicity for 

phosphinate esters is known to be correlated and limited by the octanol/water partition 

coefficient (Kow). Above a log Kow value of >5.0, phosphinate esters show no effects at 

saturation during 96-hr exposures to fish. Phosphinate esters which are solids at room 

temperature may show no toxicity at saturation at lower Kow values depending on the melting 

point, i.e., the higher the melting point at a given Kow, the greater the likelihood that no toxicity 

will be observed at saturation. For solids, the no effects at saturation has to be determined on a 

case-by-case basis. There are no measured upper Kow limits for chronic toxicity at this time, but 

it may not be much above a log Kow = 8. Future testing will determine Kow limits. 

Hazard Concerns. 

The toxicity for phosphinate esters has been determined through SAR analysis. SARs for 

freshwater species: 

log fish 96-h LC50 (millimoles/L) = -1.201 -0.260 log Kow 

where n=2, R2=1.0, LOGKOW (SRC)<5, MW<1000; 

log daphnid 48-h LC50 (millimoles/L) = -1.501 -0.260 log Kow

(SRC)<5, MW<1000; 

where n=2, R2=1.0, LOGKOW 

log green algal 96-h EC50 (mmol/L) = -1.974 -0.332 log Kow 

where n=2, R2=1.0, LOGKOW(SRC)<6.4, MW<1000, based on test data for Pseudomonas 

putida; 

log fish ChV (millimoles/L) = -2.210 -0.499 log Kow 

where n=2, R2=1.0, LOGKOW(SRC)<8, MW<1000, based on F96÷ACR10; 

log daphnid ChV (millimoles/L) = -2.445 -0.407 log Kow 

where n=2, R2=1.0, LOGKOW(SRC)<8, MW<1000, based on D48÷ACR10; and 

log algal ChV (mmol/L) = -3.315 -0.223 log Kow 

where n=2, R2=1.0, LOGKOW(SRC)<8, MW<1000, based on test data for Pseudomonas putida. 

SARs for saltwater species: 

log fish 96-h LC50 (millimoles/L) = -1.160 -0.368 log Kow 

109

where n=2, R2

=1.0, LOGKOW(SRC)<5, MW<1000; and 

log mysid 96-h LC50 (millimoles/L) = -2,019 -0.476 log Kow 

where n=2, R2=1.0, LOGKOW(SRC)<5, MW<1000. 

Fate. 

Phosphinate esters hydrolyze in water and their rate of hydrolysis is correlated with pH: 

the more alkaline the faster the hydrolysis. The SAR for hydrolysis is: 

log hydrolysis t1⁄2 (d) = 4.325 -0.497 pH 

where n=2, R2=1.0. 

At pH 7.1, the hydrolysis t1⁄2 = 6.3 days or 150 hours. 

Boundaries. 

MW <1000. Log Kow <5.0 for acute toxicity to fish and aquatic invertebrates; log Kow 

<6.4 for toxicity to green algae as a 96-h EC50; and log Kow assumed to be <8.0 for chronic 

toxicity to aquatic organisms, but could be higher. 

General Testing Strategy. I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (OPPTS 850.1075) and daphnids (OPPTS 

850.1010) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (ai) and mean measured concentrations; 

measured TOC of dilution water in the control; ideally, mean measured concentrations in the 

highest treatment concentration should be equal the aqueous solubility limit; and solvent can be 

used to assist the aldehyde to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the test chemical significantly above its aqueous 

solubility limit. 

The algal toxicity testing (OPPTS 850.5400), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (ai) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; ideally, mean 

measured concentrations in the highest treatment concentration should be equal the aqueous 

solubility limit; and solvent can be used to assist the aldehyde to reach its aqueous solubility 

limit quicker, but cannot be used to artificially enhance the water solubility of the test chemical 

significantly above its aqueous solubility limit. 

If there is no significant risk from the PMN chemical after the results of the 

environmental base set have been integrated into the risk assessment, then no further testing is 

recommended. However, if there is a significant risk, then go to Tier 2. 

110

Tier 2. Aerobic biodegradability according to either of the following test guidelines: 

Ready Biodegradability OPPTS 835.3110 

Sealed Vessel CO2 Production Test OPPTS 835.3120 

If there is no significant risk from the PMN chemical after the results of biodegradation 

testing have been integrated into the risk assessment, then no further testing is recommended. 

However, if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing 

(OPPTS 850.1400), with flow-through methods; measured concentrations; effective 

concentrations based on 100% active ingredients (AI) and mean measured concentrations; 

statistical analysis of effective concentrations at days 7, 14, 21, and 28; measured TOC of 

dilution water in the control; ideally, mean measured concentrations in the highest treatment 

concentration should be equal the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN significantly above its aqueous solubility limit; and the 7-d ELS 

stage toxicity test cannot be substituted for the 28-d ELS toxicity test because the 7-d ELS 

toxicity test may underestimate chronic toxicity measured by the 28-d ELS toxicity test when the 

Chronic Values are compared. 

Daphnid chronic toxicity testing (OPPTS 850.1300), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; ideally, mean measured concentrations in 

the highest treatment concentration should be equal the aqueous solubility limit; solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN significantly above its aqueous solubility 

limit; and the 7-d daphnid chronic toxicity test cannot be substituted for the 21-d toxicity test 

because the daphnid 7-d short-term chronic toxicity test may underestimate chronic toxicity 

measured by the daphnid 21-d chronic toxicity test when the chronic values are compared. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity 

tests (i.e., the early seeding growth test [OPPTS 850.4230], the earthworm toxicity test [OPPTS 

850.6200], and the soil microbial community bioassay [OPPTS 850.5100]) will be recommended 

for terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant 

whole life cycle test, the plant uptake test, and the soil microbial community bioassay. 

September 1996. 

111

Category: Polyanionic Polymers (& Monomers) Environmental Toxicity 

Definition. 

There are two subcategories of polymers that are of concern: 

- polyaromatic sulfonates - condensation products of sulfonated aromatics with 

formaldehyde, and 

- polyacrylates with free carboxyl groups. 

This category includes monomers with two or more acid groups and which act like organic acid 

chelators. The acid groups may include carboxylic acids, silicic acids, phosphoric acid, and 

sulfuric acids. These acids may also contain thiol substitutions. The acid groups on a monomer 

may be all of the same type of acid or may be a mixture of acids. The monomeric nucleus may 

include carbon, silica, oxygen, sulfur, and nitrogen, or mixtures of these elements. Members of 

this category must be water soluble or water self-dispersing. Molecular weights can be > 1000. 

Hazard Concerns. Polyaromatic sulfonates are moderately toxic to fish, daphnids, and algae. 

The polyacrylates are toxic to algae only. There is no apparent relationship between charge 

density and toxicity, and no QSAR (quantitative structure-activity relationship) has been 

developed for these polymers, or the polyanionic monomers. Polyanionic monomers (as salts, 

e.g., Na or K salts) are moderately toxic to green algae, but show low toxicity to fish and 

daphnids. It is assumed that the toxicity of these compounds is due to over-chelation of nutrient 

elements needed for algal growth and that this toxicity will be mitigated in the presence of Ca++ 

either added to the compound before testing or present in the growth/test medium at a hardness 

of about 150 mg/L as CaCO3. 

Boundaries. Polymers must be water-soluble. Molecular weights are generally >1,000. 

General Testing Strategy 

To address ecotoxicity concerns, for polycarboxylic acids (polyacrylates) and polyanionic 

monomers, algal testing (static methods, nominal concentrations) is recommended, in 3 separate 

tests: 1) the test substance as is, 2) with equivalent of calcium ion, and 3) with growth medium at 

150 mg/L hardness, as CaCO3). For polyaromatic sulfonates, base set aquatic toxicity testing 

(flow through methods, measured concentrations) in algae, daphnids, and fish is recommended. 

September, 1988; revised April, 1991 

112

Category: Polycationic Polymers Environmental Toxicity 

Definition. Any polymer that exists in the environment with multiple positive charges is a 

member of this class. Such structures include polyamines, polyquaternary ammonium, 

polysulfonium, and polyphosphonium compounds. 

Hazard Concerns. Members of the category are toxic to fish, invertebrates, and algae. Algae 

are six-fold more sensitive than fish and daphnids. It is presumed that these compounds act on 

the surface of organisms and need not be absorbed. Toxicity increases exponentially with 

increasing charge density at cationic equivalent weights of >400. At lower charge equivalent 

weights, toxicity does not increase. A number of QSARs (quantitative structure-activity 

relationships) have been developed to predict the toxicity of polycationic polymers. 

Boundaries. Polymers must be water-soluble or water-dispersible. Molecular weights are >300 

although the typical new chemical polycationic polymer has a molecular weight in excess of 

1000. EPA has been engaged in discussions with the Cationic Flocculant Producers Association 

in an attempt to identify and develop a set of tests on representative polycationic polymers which 

could better define the limits of the category. 

General Testing Strategy 

To address ecotoxicity concerns, for polymers with % amine nitrogen <0.7% and >0.1%: base 

set acute aquatic toxicity testing in algae, daphnids, and fish, plus humic acid testing in fish (20 

mg/L humic acid in dilution water and 10 mg/L) is recommended. All testing uses static 

method, nominal concentrations. For some members of the class, a test of sorbed chemical using 

a benthic organism may also be recommended. 

September, 1988; periodically revised. 

113

Category: Polynitroaromatics Environmental Toxicity 

This category includes all dinitroaromatics and trinitroaromatic compounds, for example, 

dinitrobenzenes, dinitroanilines, dinitrophenols, and dinitropyridines. Polynitroaromatics 

probably act by uncoupling of oxidative phosphorylation (Doull et al 1980). It is assumed that 

these compounds need to be absorbed to be toxic, therefore, compounds with MWs > 1000 will 

be excluded from this category. Acute toxicity for polynitroaromatics which are liquids at room 

temperature is assumed to be limited by the octanol/water partition coefficient (Kow). Above a 

log Kow value of => 7.00 (based on test data for anilines reported Veith and Broderius 1987), 

polynitroaromatics are not expected to show toxic effects at saturation during 96-h exposures. 

Polynitroaromatics which are solids at room temperature may show no toxicity at saturation at 

lower Kow values depending on the melting point, i.e., the higher the melting point at a given 

Kow, the greater the likelihood that no toxicity will be observed at saturation. For solids, the no 

effects at saturation has to be determined on a case-by-case basis. There are no known Kow limits 

for chronic toxicity at this time, but it may not be much above a log Kow = 10 for liquid 

polynitroaromatics. Future testing will determine this Kow limit. 

Hazard Concerns. The acute and chronic toxicity for several classes of polynitroaromatics 

have been determined through SAR Analysis: 

dinitroanilines: 

fish 96-h LC50 (mM/L)= -0.027 -0.596 log Kow; N=2; R2=1.0 

daphnid 48-h LC50 (mM/L)= -0.296 -0.558 log Kow

ow; N=2; R2

=1.0 

; N=2; R2=1.0 

fish ChV (mM/L)= -0.91 -0.661 log K

dinitrobenzenes: 

fish 96-h LC50 (mM/L)= -1.867 -0.333 log Kow; N=2; R2=1.0 

daphnid 48-h LC50 (mM/L)= -0.325 -0.634 log Kow; N=3; 

R2

=0.86 

fish ChV (mM/L)= -3.0 -0.40 log Kow; N=2; R2=1.0 

daphnid ChV (mM/L) = -0.7 -0.625 log Kow; N=2; R2

=1.0 

dinitrophenols: 

fish 96-h LC50 (mM/L)= -0.285 -0.559 log Kow; N=4; R2=0.96 

daphnid 48-h LC50 (mM/L)= 0.083 -0.632 log Kow; N=7; 

R2

=0.85 

fish ChV (mM/L)= -1.78 -0.552 log Kow; N=4; R2

=1.0 

daphnid ChV (mM/L) = -0.465 -0.654 log Kow; N=2; R2=1.0 

Polynitroaromatics are known to be more toxic than predicted by the neutral organic SARs. 

Members of this category exhibit toxicity ranging from low toxicity (i.e., > 100 mg/L) to high 

toxicity (i.e., < 1 mg/L) depending on their Kow and MW.

114

Fate: Polynitroaromatics are expected to be subject to rapid direct and indirect photolysis under 

environmentally realistic conditions. 

Boundaries.: There are no known lower boundaries. The upper boundaries will be based on 

Kow and MW. Acute toxicity expected with log Kow < 7.0; no effects at saturation during 96-h 

exposures when log Kow >= 7.0. Chronic toxicity has no known upper bound for log Kow, but it 

is probably near 10. MW will be < 1000. The environmental base set of tests will be requested 

for aquatic releases and the terrestrial base set of tests will be recommended for terrestrial 

exposures. When the log Kow is >= 7.0, chronic toxicity testing with fish and daphnids will be 

recommended. 

General Testing Strategy. 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (40 CFR 797.1400) and daphnids (40 CFR 

797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; the highest treatment 

concentration on a nominal-basis should equal the aqueous solubility limit; and solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

The algal toxicity testing (40 CFR 797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis equal to the aqueous solubility limit; and solvent can 

be used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

If there is no significant risk from the PMN after the results of the environmental base set 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 2. 

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, go to Tier 4. 

115

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40.796.3765 (b)(2) and (c)(2)], expose to sunlight 

for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive species 

from environmental base set. For example, if the most sensitive species from the environmental 

base set has an EC50 value = 2.0 mg PMN/L (based on 100% active ingredients [AI]), then 

prepare a 5.0 mg PMN per liter stock solution based on 100% AI using the standard humiccontaining solution. This stock solution is exposed to sunlight for at least 6 half-lives to ensure 

that all of the PMN has been photolyzed, and then this stock solution is used to retest the most 

sensitive aquatic species to determine if the photolysis products of the PMN are more or less 

toxic that the PMN. 

Tier 4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR 797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; the highest treatment concentration on a nominal-basis should be set at the aqueous 

solubility limit; solvent can be used to assist the PMN to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the PMN beyond its 

aqueous solubility limit; and the 7-d ELS stage toxicity test cannot be substituted for the 28-d 

ELS toxicity test because Van Leeuwen et al (1990) have demonstrated that the 7-d ELS toxicity 

test underestimated the chronic toxicity of anilines measured by the 28-d ELS toxicity test by 

>5.3 times when the NOECs were compared (see Table VII in Van Leeuwen); 

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; the highest treatment concentration on a 

nominal-basis should be set at the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN beyond its aqueous solubility limit; and the 7-d daphnid chronic 

toxicity test cannot be substituted for the 21-d toxicity test because Van Leeuwen et al (1990) 

have demonstrated that the fish 7-d ELS toxicity test underestimated the chronic toxicity of 

anilines 

116

measured by the fish 28-d ELS toxicity test by >5.3 times when the NOECs were compared (see 

Table VII in Van Leeuwen). 

Aerobic biodegradability according to any one of the following test guidelines (listed in 

order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity tests 

(i.e., the early seeding growth test, the earthworm toxicity test and the soil microbial community 

bioassay) will be recommended for terrestrial exposures. Chronic toxicity testing for terrestrial 

organisms include: the plant whole life cycle test, the plant uptake test, and the soil microbial 

community bioassay. 

References. 

Doull J, Klaassen CD, and Amdur MO. 1980. Casarett and Doull's Toxicology. The Basic 

Science of Poisons. Second Ed. New York, NY: Macmillan Pub. Co., Inc. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

Veith GD and Broderius SJ. 1987. Structure-toxicity relationships for industrial chemicals 

causing type (II) narcosis syndrome. In Kaiser KLE (ed), QSAR In Environmental Toxicology -

II, p 385-391. Boston, MA: D. Reidel Publishing Company. 

May, 1991 

117

Category: Respirable, Poorly Soluble Particulates Health Only 

Definition. This category includes a variety of inorganic, poorly soluble (as designated in ILSI 

2000) particulates. Typically, they are oxides of various metals or nonmetals (i.e., silicon) 

Boundaries. Potential for respirability--that is, if there are any particles #10 : in diameter in 

the material being handled by workers. Summarized below are currently available test data on 

five different poorly soluble particulates–silica, talc, titanium dioxide, PMN 96-175 (lithium 

manganese oxide), and carbon black. The suitability of one or more of these analogues for a 

particular PMN particulate must be determined on a case-by-case basis. Risk is to be assessed 

by the margin of exposure method for the reason stated in the next paragraph. 

Hazard Concerns 

The category concerns discussed here are limited to effects on the lung as a result of inhaling the 

particles. Broadly, as shown in rat inhalation studies, these effects range from inflammation to 

fibrosis to, potentially, cancer. Because it is still not known with certainty whether high lung 

burdens of poorly soluble particulates can lead to lung cancer in humans via mechanisms similar 

to those of the rat, in the absence of mechanistic data to the contrary, it must be assumed that the 

rat model can identify potential carcinogenic hazards to humans. Since the apparent 

responsiveness of the rat model at overload is dependent on coexistent chronic active 

inflammation and cell proliferation, at lower lung doses in which chronic active inflammation 

and cell proliferation are not present, no lung cancer hazard is anticipated (ILSI 2000). 

Some of the particulates may contain metals, for example, chromium, that may present other and 

more imminent toxicities, depending on the bioavailability of the metal ions. Thus, the toxicities 

of the metal components of the particulates must also be assessed, and on a case-by-case basis. 

Lung Toxicity of Five Poorly Soluble Particulates 

1. Fibrogenicity/Carcinogenicity of Crystalline Silica 

Humans. Based on “sufficient evidence” for the carcinogenicity of inhaled crystalline silica 

from occupational sources, the International Agency for Research on Cancer (IARC, 1997) has 

classified crystalline silica as a Group 1 carcinogen in humans. According to IARC, studies of 

the following populations provided the least-confounded examinations of an association between 

silica exposure and cancer risk: gold miners, stone industry workers, granite shed and quarry 

workers, crushed stone industry workers, diatomaceous earth industry workers, refractory brick 

workers, pottery workers, and cohorts of registered silicotics. Not all of these studies 

demonstrated excess cancer risks; but, in view of the large number of epidemiological studies 

undertaken and the wide range of populations and exposure circumstances, some nonuniformity 

of results would be expected. In some studies, increasing risk gradients have been observed in 

relation to dose surrogates--cumulative exposure, duration of exposure, or the presence of 

radiographically defined silicosis--and, in one instance, to peak intensity exposure. For these 

reasons, the IARC Working Group 

118

concluded that overall, the epidemiological findings support increased lung cancer risks from 

inhaled crystalline silica resulting from occupational exposure. 

Animals. IARC (1997) has concluded that there is “sufficient evidence” in experimental animals 

for the carcinogenicity of crystalline silica. A number of studies (rev.in: IARC, 1997; Woo et 

al., 1988; Holland, 1990) have demonstrated that, in addition to silicosis/fibrosis, pulmonary 

tumors are induced in rats exposed to quartz (Mini-U-Sil; a common form of crystalline silica) 

by inhalation, single intrapleural, intraperitoneal, and/or intratracheal administration. In a 24-

month inhalation study in rats, the lowest tested dose of respirable crystalline silica particles to 

induce lung tumors (Lowest Observed Adverse Effect Level, or LOAEL) was 0.74 mg/m3 

. 

K Note for Cases Using Silica as Primary Analogue: For LOAEL doses, the Agency 

considers a Margin of Exposure (MOE) of 1,000 or greater as representing a low order of 

toxicity for health endpoints for which a threshold dose is deemed appropriate. In this instance, 

exposures would have to be reduced to 0.0007 mg/m3

 to achieve a MOE of 1,000, a 

concentration that is practically impossible to achieve. Because the LOAEL of 0.74 mg/m3 is 

based on test data on pure silica and because silica is considered to be a much more potent lung 

toxicant than crystalline particulates containing silica, the Agency has adopted the NIOSH 

REL (Recommended Exposure Level) for silica, 0.05 mg/m3, as a NCEL1/ (New Chemical 

Exposure Limit - see http://www.epa.gov/oppt/newchems/ncelmain.htm for more 

information) concentration that would adequately protect workers from crystalline 

particulates containing silica. This NCEL replaces the former one based on OSHA 

Permissable Exposure Limit (PEL) for silica 0.1 mg/m3

. 

2. Fibrogenicity/Carcinogenicity of Talc 

Humans. Epidemiology studies suggest an association between nonfibrous talc (a finely 

powdered hydrous magnesium silicate) and lung cancer risk. The OSHA PEL for talc is 20 

mppcf (million particles per cubic foot), and the NIOSH-recommended 8-hr TWA concentration 

is 2 mg/m3. 

Animals. In an NTP inhalation study (NTP TR 421, 1993), male and female F344 rats were 

exposed to 0, 6, or 18 mg/m3

 talc for 113 and 122 weeks, respectively. There was clear evidence 

of the carcinogenicity of talc in female rats based on the increased incidence of 

alveolar/bronchiolar adenomas and carcinomas of the lung in the 18-mg/m3

 group (LOAEL). 

The No Observed Adverse Effect Level (NOAEL) from this study is 6 mg/m3 . The NCEL 

for analogous particulates would be 0.06 mg/m3. 

3. Fibrogenicity/Carcinogenicity of Titanium Dioxide (TI) 

Humans. According to IARC (ACGIH 1993), there is inadequate evidence for the 

carcinogenicity of TI in humans. [There is limited evidence for the carcinogenicity of TI in 

experimental animals.] Overall evaluation: TI is not classifiable as to its carcinogenicity to 

119

humans. The OSHA PEL’s for nuisance dust (in which TI is included) are 15 mg/m3

 total 

particulates and 5 mg/m3

 respirable fraction. The ACGIH TLV-TWA is 10 mg/m3 of total dust 

containing no asbestos and <1% crystalline silica. 

The various literature case reports of lung toxicity in TI-exposed workers are generally 

inconclusive because of several factors--smoking; other conditions, such as tuberculosis; or 

incomplete data on TI exposure histories. 

In one fairly comprehensive cohort study, Chen and Fayerweather (1988, as summarized in 

ACGIH 1993) analyzed lung cancer mortality and incidence of chronic respiratory disease, chest 

x-ray abnormality, and pulmonary fibrosis among 1,576 workers exposed to TI for at least 1 yr at 

two production facilities between 1935 and 1984. Of the 211 deaths, 14 were attributed to 

respiratory cancer and 11 to nonmalignant respiratory disease compared with 18.3 and 13.8 cases 

expected, respectively, based on US mortality data. Expected deaths based on company 

mortality data since 1957 were 16.6 from respiratory cancer and 8.3 from nonmalignant 

respiratory disease. The authors concluded that the increase in deaths from nonmalignant 

respiratory disease compared with company data was not statistically significant. They further 

concluded that there was no significant association between exposure to TI and the respiratory 

diseases studied. 

Animals. There is limited evidence for the carcinogenicity of TI in experimental animals. Twoyear inhalation studies in animals are summarized below. 

(1) Lee et al. (1986, as cited in ACGIH 1993 and in USEPA 1983) exposed Charles River-CD 

rats to 0, 10, 50, or 250 mg/m3

 for 6 hr/day 5 days/wk for 2 yr. The mean respirable fractions 

were 93.7% or greater. Squamous cell carcinomas developed after exposure to the highest dose 

for the full 2 yr. The authors considered the carcinomas to be unique, experimentally induced 

tumors in rats and to be of questionable relevance to humans. Given the amount of dust in the 

rat lungs, the tumors were postulated to be the result of saturation of normal pulmonary 

clearance mechanisms. There were minute areas of lung fibrosis at the two higher exposure 

levels. 

At 50 mg/m3

, massive accumulations of dust-laden macrophages, foamy dust cells, and free 

particles were considered indicative of such an overload. At 10 mg/m3

, the architecture of the air 

spaces remained intact and there was no significant formation of scar tissue. The NOAEL is 10 

mg/m3

. 

(2) Heinrich et al. (1995, abstract only) exposed Wistar rats to diesel engine exhaust, carbon 

black, or ultrafine TI for 2 yr. Particle exposure concentrations were increased during the course 

of the experiment. The average particle concentration of TI was 10 mg/m3. Lung tumor rates 

(not given) increased with increasing cumulative particle exposure times, independent of the 

type of particle. 

(3) Trochimowicz et al. (1988, abstract only) exposed Charles River-CD rats to 10, 50, or 250 

120

mg/m3

 TI for 6 hr/day, 5 days/wk for 104 wk. Microscopic findings included alveolar cell 

hyperplasia, dust deposition, and minute areas of collagen fiber deposition associated with 

cholesterol giant cell granulomas. The earliest indicator of TI exposure was alveolar cell 

hyperplasia. Lung tumors were only found in rats exposed to 250 mg/m3

. The NOAEL from 

this study is 10 mg/m3. 

On the basis of the NOAEL’s from the above studies, the NCEL for analogous particulates 

would be 0.1 mg/m3

. However, this would make the NCEL for TI analogues identical to that for 

silica, a highly potent lung toxicant that IARC (1997) has classified as a Group 1 carcinogen in 

humans (see section 1, above). Therefore, it was decided to use the OSHA PEL for TI, which is 

5 mg/m3 (respirable fraction), as the NCEL for TI analogues. 

4. Lung Toxicity of PMN 96-175, Lithium Manganese Oxide 

Animal Data Only. Rats were exposed by inhalation to 0 (air controls), 1, 4, or 16 mg/m3 of the 

PMN substance 6 hr/day, 5 days/wk for 90 days. At the highest concentration, rats developed 

inflammation of the lung and larynx. Similar results were seen in the 14-day range-finding study 

at concentrations ranging from 10 to 100 mg/m3

. The NOAEL from this study is 4 mg/m3. 

The NCEL for analogous particulates would be 0.04 mg/m3

. 

5. Fibrogenicity/Carcinogenicity of Carbon Black 

Chronic inhalation of carbon black produced pulmonary inflammation, fibrosis, and lung tumors 

in rats (Nikula et al. 1995, Heinrich et al. 1995). These effects were observed at dust 

concentrations of 2.5, 6.6, and approximately 10 mg/m3 carbon black. The LOAEL from these 

studies is 2.5 mg/m3. The NCEL for analogous particulates would be 0.0025 mg/m3. [The 

OSHA PEL for carbon black is 3.5 mg/m3.] 

General Testing Strategy 

A 90-day inhalation toxicity test (CFR 870.3465) in rats with special attention to histopathology 

(inflammation and cell proliferation) of the lung tissues and to various parameters of the 

bronchoalveolar lavage fluid (BALF), e.g., marker enzyme activities, total protein content, total 

cell count, cell differential, and cell viability. It is not necessary to look at internal organs. It is 

recommended that a recovery period of 60 days be included to assess the progression or 

regression of any lesions. If the results of the subchronic study indicate that the PMN particles 

have carcinogenic potential, a 2-year inhalation bioassay in rats may be warranted. 

REFERENCES 

ACGIH. 1993. American Conference of Governmental Industrial Hygienists: Threshold Limit 

Values for Chemical Substances and Physical Agents and Biological Exposure Indices, 1993-

121

1994. Cincinnati, Ohio: ACGIH. 

Heinrich U, Fuhst R, Rittinghausen S, Creutzenberg O, Bellmann B et al. 1995. Chronic 

inhalation exposure of Wistar rats and two different strains of mice to diesel engine exhaust, 

carbon black, and titanium dioxide. Inhal Toxicol 7:533-556. Abstract only. 

Holland LM. Reg. Toxicol. Pharmacol. 12:224-237, 1990 

IARC. 1997. International Agency for Research on Cancer. Monographs. Vol. 68, pp.41-336. 

ILSI. 2000. International Life Sciences Institute. Workshop: The relevance of the rat lung 

response to particle overload for human risk assessment. Inhal Toxicol 12: 1-17. 

Nikula KJ, Snipes MB, Griffith WC, Henderson RF, Mauderly JL. 1995. Comparative 

pulmonary toxicities and carcinogenicities of chronically inhaled diesel exhaust and carbon 

black in F344 rats. Fund Appl Toxicol 25:80-94. 

NTP. Toxicology and Carcinogenesis Studies of Talc in F334/N rats and B6C3F1 mice. National 

Toxicology Program, Technical Report No. 421, 1993. 

Trochimowicz HJ et al. 1988. J Appl Toxicol 8:383-435. Abstract only. 

USEPA. 1983. Status report for 8EHQ-1083-0497. Preliminary findings from a 2-yr rat 

inhalation study of titanium dioxide conducted by E.I. Du Pont de Nemours & Co., Inc. From 

Justine Welch, Chief, Chemical Risk Indentification Section, to Frank Kover, Chief, Chemical 

Screening Branch, Existing Chemicals Assessment Div., OPPT, USEPA. 

Woo, Y.-T., Lai, D.Y., Arcos, J.C., and Argus, M.F.: Chemical Induction of Cancer, Vol. III C, 

Academic Press, p. 508, 1988. 

October, 2002 

122

Category: Rosin Environmental Toxicity 

This category includes rosin, abietic acid, abietinic acid, sylvic acid, their salts, and 

polymeric forms whose MW < 1000. The mode of toxic action of rosin is unknown. It is 

assumed that these compounds need to be absorbed to be toxic, therefore, compounds with MWs 

> 1000 will be excluded from this category. It is also assumed that these compounds need to be 

water soluble to be toxic, therefore, compounds with water solubilities (WS) < 0.001 mg/L 

(ppm) will also be excluded from this category. 

Hazard Concerns. The acute toxicity for rosin towards fish has been measured to be between 

0.410 to 0.700 mg/L by Leach and Thakore (1976 and 1978). Toxicity to aquatic invertebrates 

and green algae have no been reported. Based on these data, rosin presents a high concern for 

toxicity towards the aquatic environment. 

Boundaries. The only lower boundary is water solubility which is set at 0.001 mg/L (ppm). 

The only upper boundary will be set at a MW > 1000 for stable compounds. The environmental 

base set of tests will be requested for aquatic releases and the terrestrial base set of tests will be 

recommended for terrestrial exposures. 

General Testing Strategy. 

The aquatic base set of environmental toxicity tests will be recommended for aquatic 

exposures. The acute toxicity tests for fish (CFR §797.1400) and daphnids (CFR §797.1300) will 

be done using the flow-through method with measured concentrations; effective concentrations 

will be based on 100% active ingredients (AI) and mean measured concentrations; measured 

TOC of dilution water in the control; the highest treatment concentration on a nominal-basis 

should equal the aqueous solubility limit; and solvent can be used to assist the PMN to reach its 

aqueous solubility limit quicker, but cannot be used to artificially enhance the water solubility. 

The algal toxicity testing (CFR §797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis equal to the aqueous solubility limit; and solvent can 

be used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility. 

Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (CFR 

§797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; the highest treatment concentration on a nominal-basis should be set at the aqueous 

solubility limit; solvent can be used to assist the PMN to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility; and the 7-d ELS stage 

toxicity test cannot be substituted for the 28-d ELS toxicity test because Van Leeuwen et al 

123

(1990) have demonstrated that the 7-d ELS toxicity test underestimated the chronic toxicity of 

anilines measured by the 28-d ELS toxicity test by >5.3 times when the NOECs were compared 

(see Table VII in Van Leeuwen); 

Daphnid chronic toxicity testing (CFR §797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; the highest treatment concentration on a 

nominal-basis should be set at the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility; and the 7-d daphnid chronic toxicity test cannot be substituted for the 21-d 

toxicity test because Van Leeuwen et al (1990) have demonstrated that the fish 7-d ELS toxicity 

test underestimated the chronic toxicity of anilines measured by the fish 28-d ELS toxicity test 

by >5.3 times when the NOECs were compared (see Table VII in Van Leeuwen). 

The terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test 

[§797.2800], the earthworm acute toxicity test [§795.150], and the soil microbial community 

bioassay [795.3700]) will be recommended for terrestrial exposures. Chronic toxicity testing for 

terrestrial organisms include: the plant whole life cycle test [§797.2830], the plant uptake test 

[§797.2850], and the soil microbial community bioassay. 

References. 

Leach , J. M. and Thakore, A. N., 1976. Toxic constituent in mechanical pulping effluents. 

Tappi, 59:129. 

Leach , J. M. and Thakore, A. N., 1978. Compounds toxic to fish in pulp mill waste streams. 

Progr. Water Technol. (G.B.) 9:787. 

Van Leeuwen CJ, Adema DMM, and Hermens J. 1990. Quantitative structure-activity 

relationships for fish early life stage toxicity. Aquatic Toxicology 16:321-334. 

January, 1994 

124

Category: Stilbene, derivatives of 4,4-bis(triazin-2-ylamino)-

Human Health (case-by-case) 

Definition. Any water soluble (sulfonated) derivative of 4,4-bis(triazin-2-ylamino) stilbene is 

considered to be a member of this category. 

Hazard Concerns. EPA previously identified hazard concerns for the possible 

developmental/reproductive toxicity of new chemicals falling into this stilbene, derivatives of 

4,4-bis(triazin-2-ylamino)- category based on published test results for a member of the 

category. EPA has reviewed test data developed by the Stilbene Whitening Agent Task Force of 

the Ecological and Toxicological Association of Dyes and Organic Pigments Manufacturers 

(ETAD). These studies consisted of a range-finding and definitive 2-generation rat study 

(gavage) and range-finding and definitive developmental toxicity studies in rats and rabbits 

(gavage) for C.I. Fluorescent Brightener 220 (CAS No. 16470-24-9). Based on the results from 

these studies, EPA has concluded that available information does not support continued 

identification of stilbenes as a new chemical category presenting concerns for possible 

developmental/reproductive toxicity. EPA will continue to evaluate the potential health 

concerns for new chemical stilbenes that are notified but, with this change, will not apply a 

category understanding as regards potential developmental/reproductive toxicity. 

References. 

Breslin, WJ. A pilot prenatal developmental toxicity study of C.I. Fluorescent Brightener 220 

and C.I. Fluorescent Brightener 339 administered via oral gavage to rats. MPI Research 

Laboratory Study Identification 795-001, August 18, 1998a. 

Breslin, WJ. A pilot prenatal developmental toxicity study of C.I. Fluorescent Brightener 220 

and C.I. Fluorescent Brightener 339 administered via oral gavage to New Zealand White rabbits. 

MPI Research Laboratory Study Identification 795-002, August 18, 1998b. 

Turck, PA. Prenatal developmental toxicity study of C.I. Fluorescent Brightener 220 

administered via oral gavage to rats. MPI Research Laboratory Study Identification 795-003, 

December 2, 1999. 

125

Turck, PA. Range-finding reproduction study of C.I. Fluorescent Brightener 220 administered 

via oral gavage to rats. MPI Research Laboratory Study Identification 795-005, June 8, 2000a. 

Turck, PA. Prenatal developmental toxicity study of C.I. Fluorescent Brightener 220 

administered via oral gavage to New Zealand White rabbits. MPI Research Laboratory Study 

Identification 795-004, January 27, 2000b. 

Turck, PA. Two generation reproduction and fertility study of C.I. Fluorescent Brightener 220 

administered via oral gavage in rats. MPI Research Laboratory Study Identification No. 795-

006, August 24, 2001. 

Previous Category Statement References. 

Burg, AW, Rohovsky, MW & Kensler, CJ (1977). Current status of human safety and 

environmental aspects of fluorescent whitening agents used in detergents in the United States. 

Critical Review & Environmental Control, 7, 91-120. 

Gloxhuber, CH & Bloching, H (1978). Toxicologic properties of fluorescent whitening agents. 

Clinical Toxicology, 13, (2), 171-203. 

Keplinger, ML, Fancher, OE, Lyman, FL & Calandra, JC (1974). Toxicologic studies of four 

fluorescent whitening agents. Toxicology & Applied Pharmacology, 27, 494-506. 

Keplinger, ML, Lyman, FL & Calandra, JC (1975). Three-generation reproduction studies with 

FWAs. In: Flourescent Whitening Agents. R. Anliker & G. Muller (Eds.). Stuttgart, Germany: 

Georg Thieme Publishers. 

Kramer, JB (1992). Fluorescent whitening agents. In: The Handbook of Environmental 

Chemistry, 3, (part F), 351-366. O. Hutzinger (Ed.). Heidelberg, Germany: Springer-Verlag 

Berlin. 

Lorke, D (1975). Studies of embryo toxicity in rats & rabbits. In: Flourescent Whitening 

Agents. R. Anliker & G. Muller (Eds.). Stuttgart, Germany: Georg Thieme Publishers. 

Lyman, FL, Schulze, J, Ganz, CR, Stensby, PS, Keplinger, ML & Calandra, JC (1975). Longterm toxicity of four fluorescent whitening agents. Food, Cosmetics & Toxicology, 13, 521-527. 

Poiger, T & Giger, W (1991). Determination of fluorescent whitening agents in sewage and 

sewage sludge by high performance liquid chromatography. Reprint of a poster presented at the 

meeting of the Swiss Chemical Society in Bern, Switzerland. October 18, 1991. EAWAG/ETH, 

CH-8600 Dubendorf, Switzerland. 

Zinkernagel, R (1975). Fluorescent whitening agents in the environment. In: Flourescent 

Whitening Agents. R. Anliker & G. Muller (Eds.). Stuttgart, Germany: Georg Thieme 

Publishers. 

8E-CAP - 0024. Report to Ciba-Geigy Corporation. Teratogenic study with FA-15 in Albino 

126

rabbits, May 23, 1972. Submitted to USEPA on October 9, 1992. 

PB81-148819. Information Hazard Profiles on Potential Occupational Hazards. Vol. 2. 

Chemical Classes Fluorescent Whitening Agent (FWA's). National Institute for Occupational 

Safety and Hazard, Rockville, Maryland. December 1979. 

January, 1992; revised December, 1994; revised August, 2002. 

127

Category: Thiols Environmental Toxicity 

This category includes all thiols or mercaptans. It is assumed that thiols have to be absorbed to 

be toxic, therefore, compounds with MWs > 1000 will be excluded from this category. Acute 

toxicity for thiols which are liquids at room temperature is known to be limited by the 

octanol/water partition coefficient (Kow). Above a log Kow value of <6.5 (CLOGP), thiols show 

no effects at saturation during 96-h exposures. Thiols which are solids at room temperature may 

show no toxicity at saturation at lower Kow values depending on the melting point, i.e., the higher 

the melting point at a given Kow, the greater the likelihood that no toxicity will be observed at 

saturation. For solids, the no effects at saturation has to be determined on a case-by-case basis. 

There are no known Kow limits for chronic toxicity at this time, but it may not be much above a 

log Kow of 8 to 9 for liquid thiols. Future testing will determine this Kow limit. 

Hazard Concerns. The acute toxicity for thiols has been determined through SAR Analysis: 

fish 96-h LC50 (millimoles/L) = -1.022 - 0.447 log Kow 

daphnid 48-h LC50 (millimoles/L) = -3.2 - 0.097 log Kow 

Effective concentrations for green algal 96-h EC50 should be assumed to be similar to fish and 

daphnids. 

Thiols which are substituted with a carboxylic acid will be about 10 times less toxic than 

predicted by this SAR at pH 7. Use the Kow for the free acid. 

Members of this category exhibit toxicity ranging from low toxicity (i.e., > 100 mg/L) to high 

toxicity (i.e., < 1 mg/L) depending on their Kow, MW and substitutions.

Boundaries. There are no known lower boundaries. The upper boundaries will be based on Kow 

and MW. Acute toxicity expected with log Kow <6.5; no effects at saturation during 96-h 

exposures when log Kow >6.5. Chronic toxicity has no known upper bound for log Kow, but it is 

probably near 9. MW will be <1000. The environmental base set of tests will be requested for 

aquatic releases and the terrestrial base set of tests will be recommended for terrestrial 

exposures. When the log Kow is >6.5, chronic toxicity testing will be recommended. 

General Testing Strategy 

I. Release to Aquatic Ecosystems: 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for 

aquatic exposures. The acute toxicity tests for fish (CFR §797.1400) and daphnids (CFR 

§797.1300) will be done using the flow-through method with measured concentrations; effective 

concentrations will be based on 100% active ingredients (AI) and mean measured 

concentrations; measured TOC of dilution water in the control; the highest treatment 

concentration on a nominal-basis should equal the aqueous solubility limit; and solvent can be 

used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

128

The algal toxicity testing (CFR §797.1050), should be done with static methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at 24, 48, 72, and 

96 hours; test medium with at least 0.300 mg/L EDTA as a final concentration; the highest 

treatment concentration on a nominal-basis equal to the aqueous solubility limit; and solvent can 

be used to assist the PMN to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the PMN beyond its aqueous solubility limit. 

If there is no significant risk from the PMN after the results of the environmental base set 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 2. 

Tier 2. Aerobic biodegradability according to any one of the following test guidelines 

(listed in order of preference): 

Aerobic Aquatic Biodegradation 40 CFR 796.3100 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

If there is no significant risk from the PMN after the results of the aerobic biodegradation 

have been integrated into the risk assessment, then no further testing is recommended. However, 

if there is a significant risk, then go to Tier 3. 

Tier 3. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (CFR 

§797.1600), with flow-through methods; measured concentrations; effective concentrations 

based on 100% active ingredients (AI) and mean measured concentrations; statistical analysis of 

effective concentrations at days 7, 14, 21, and 28; measured TOC of dilution water in the 

control; the highest treatment concentration on a nominal-basis should be set at the aqueous 

solubility limit; solvent can be used to assist the PMN to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the PMN beyond its 

aqueous solubility limit; and the 7-d ELS stage toxicity test cannot be substituted for the 28-d 

ELS toxicity test. 

Daphnid chronic toxicity testing (CFR §797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21; measured TOC of dilution water in the control; the highest treatment concentration on a 

nominal-basis should be set at the aqueous solubility limit; solvent can be used to assist the 

PMN to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the 

water solubility of the PMN beyond its aqueous solubility limit; and the 7-d daphnid chronic 

toxicity test cannot be substituted for the 21-d toxicity test. 

II. Release to Terrestrial Ecosystems 

129

The terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test, 

the earthworm toxicity test and the soil microbial community bioassay) will be recommended for 

terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant whole 

life cycle test, the plant uptake test, and the soil microbial community bioassay. 

December, 1994 

130

Category: Substituted Triazines Environmental Toxicity 

This category includes substituted triazines which can be aromatic, partially aromatic (or

partially saturated) and unsaturated. The nitrogens in the triazine ring may be symmetrical or

asymmetrical. Substitutions on the carbons may include but not be limited to: aliphatic alcohols; 

ketones; benzene and substituted benzenes; aliphatic hydrocarbons, alkyenes and alkynes; free

amines and substituted amines; cyclic aliphatic hydrocarbons; halogens; amides; cyanides;

ethers; methoxy groups; sulfides; azido groups; and carboxylic acid esters. Substitutions on

the nitrogens may include but not be limited to: free amines and substituted amines; -N=CH;

aliphatic hydrocarbons, alkyenes and alkynes; and benzene and substituted benzenes.

Hazard Concerns. Many members of this category are commercial herbicides which are used

to control both aquatic plants and terrestrial plants. Their mode of toxic action is generally

considered to be inhibition of photosynthesis. Many members of this class are toxic to algae at <

1 mg/L and toxic to terrestrial vascular plants at < 1 mg/kg. Members of this group can also be

highly toxic to fish and aquatic invertebrates. Toxicity is expected to be related to the

octanol/water partition coefficient with respect to fish and aquatic invertebrates, but toxicity to

plants may not be related to Kow when log Kow < 5. When the log Kow is < 5, algae and

terrestrial plants are expected to be the most sensitive species. As log Kow increases, species

differences are expected to diminish. At this time there is no formalized SAR for this category

for any species. Toxicity predictions will be made using either the closest analog or averaging

data for the two closest analogs which bracket the chemical under question.

Boundaries. There are no known lower boundaries. The upper boundaries are based on Kow

and MW. When the log Kow value is < 5 mg/L, the environmental base set of tests will be

requested for aquatic releases and the terrestrial base set of tests will be recommended for

terrestrial exposures. When the log Kow is between 5 and 8, only chronic toxicity testing will be

recommended. When the log Kow is > 8, no testing will be

requested because no toxic effects at saturation will be expected. Generally, members of this

category will have MWs of less than 1000.

General Testing Strategy 

The aquatic base set of environmental toxicity tests will be recommended for aquatic exposures

and the terrestrial base set of environmental toxicity tests (i.e., the early

seeding growth test, the earthworm acute toxicity test and the soil microbial community

bioassay) will be recommended for terrestrial exposures. 

August, 1989

131

Category: Triarylmethane Pigments/Dyes 

with Non-solubilizing Groups Human Health 

Environmental Toxicity 

Other Names: Triphenylmethane Pigments/Dyes, Diphenylnaphthylmethane Pigments/Dyes 

Definition. Structurally, triarylmethane pigments/dyes are derivatives of triphenylmethane or 

diphenylnaphthylmethane. In order to achieve the required spectral absorption properties that 

characterize these dyes, amine groups (primary, secondary, or tertiary) or hydroxyl groups must 

be present on the aromatic ring positions para to the methane carbon. Amine substitutions are 

more prevalent than hydroxy substitutions (C.I. 42000-42175 for diamino derivatives, C.I. 

42500-42800 for triamino derivatives, C.I. 43800-43875 for hydroxy derivatives, and 43500-

43570 for aminohydroxy derivatives). 

Hazard Concerns. There are oncogenicity concerns for the triarylmethane pigments/dyes based 

on analogy to Gentian Violet and C.I. Basic Red 9. In addition, there are developmental and 

reproductive toxicity concerns for these compounds based on analogy to Gentian Violet and 

Malachite Green. Ecotoxicity concerns are based on QSAR predictions for delocalized cationic 

132

dyes. Cationic dyes are an established ecotoxicity category. 

Boundaries. Pigments/Dyes included in this category are the di- and tri-amino substituted 

triphenylmethane and diphenylnaphthyl-methane derivatives. Dyes substituted with solubilizing 

groups such as carboxylic acid, sulfonic acid, or halogens, are not included. Pigments that have 

essentially negligible water solubility (<1ppb) and therefore, little or no bioavailability, are also 

not included. 

General Testing Strategy 

The New Chemicals Program considers the following tests to be appropriate to address the 

potential for triarylmethane pigments/dyes to pose a significant risk. 

For Health -

1. Developmental toxicity study in two species of rodents by the oral route (40 CFR 

798.4900). 

2. Two-generation reproductive toxicity study in rodents by the oral route (40 CFR 

798.4700). 

3. Salmonella typhimurium/Ames assay with the Chinese hamster liver S9 activation 

system (40 CFR 798.5265). 

4. In vivo mouse micronucleus assay i.p. (40 CFR 798.5395). 

Tests 3. and 4. would trigger a lifetime rodent bioassay if positive. 

For Environmental toxicity and fate -

Prior to Tier 1, the following physical-chemical properties need to be established: 

Melting point (40 CFR 796.1300) or boiling point (40 CFR 796.1220), water solubility 

(40 CFR 796.1840), log Kow (40 CFR 796.1550, 796.1570 or 796.1720), and vapor pressure (40 

CFR 796.1950). 

Tier 1. The fish, daphnid, and algal (40 CFR 797.1050) acute toxicity tests from the 

aquatic base set of environmental toxicity tests will be recommended for aquatic exposures. The 

acute toxicity tests for fish (CFR §797.1400) and daphnids (CFR §797.1300) will be done using 

the flow-through method with measured concentrations, and effective concentrations will be 

based on 100% active ingredients (AI) and mean measured concentrations. 

If there is no significant risk from the PMN after the results of the fish and daphnid acute 

toxicity tests have been integrated into the risk assessment, then no further testing is 

recommended. However, if there is a significant risk, then go to Tier 2. 

133

Tier 2. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 3; if t1⁄2 > 2 days, then integrate the results into the risk assessment. If there is 

no significant risk from the PMN, then no further testing is recommended. However, if there 

remains a significant risk, then go to Tier 4. 

Tier 3a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental risk. If there is no significant risk from the photolysis 

products from the PMN, then no further testing is recommended. However, if there remains a 

significant risk, then go to Tier 4. 

Tier 3b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of PMN using the standard humic-containing solution described in the 

direct and indirect photolysis screening test [40.796.3765 (b)(2) and (c)(2)], expose to sunlight 

for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity with most sensitive species 

from environmental base set. For example, if the most sensitive species from the environmental 

base set has an EC50 value = 2.0 mg PMN/L (based on 100% active ingredients [AI]), then 

prepare a 5.0 mg PMN per liter stock solution based on 100% AI using the standard humiccontaining solution. This stock solution is exposed to sunlight for at least 6 half-lives to ensure 

that all of the PMN has been photolyzed, and then this stock solution is used to retest the most 

sensitive aquatic species to determine if the photolysis products of the PMN are more or less 

toxic that the PMN. Integrate these toxicity results into the risk assessment. If there is no 

significant risk from the PMN, then no further testing is recommended. However, if there 

remains a significant risk, then go to Tier 4. 

Tier 4. Test for aerobic biodegradability according to any one of the following test 

guidelines (listed in order of preference): 

Modified Sturm Test 40 CFR 796.3260 

Closed Bottle Test 40 CFR 796.3200 

Modified OECD Screening Test 40 CFR 796.3240 

Modified MITI Test (I) 40 CFR 796.3220 

Modified AFNOR Test 40 CFR 796.3180 

Integrate the results for aerobic biodegradability into the risk assessment. If there is no 

significant risk from the PMN, then no further testing is recommended. However, if there 

remains a significant risk, then do chronic toxicity testing for fish and daphnids: 

Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (CFR 

§797.1600), with flow-through methods; measured concentrations; effective concentrations 

134

based on 100% active ingredients (AI) and mean measured concentrations; and statistical 

analysis of effective concentrations at days 7, 14, 21, and 28. 

Daphnid chronic toxicity testing (CFR §797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% active ingredients (AI) and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, and 

21. 

For Terrestrial ecosystemsThe terrestrial base set of environmental toxicity tests (i.e., the early seeding growth test, 

the earthworm toxicity test and the soil microbial community bioassay) will be recommended for 

terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant whole 

life cycle test, the plant uptake test, and the soil microbial community bioassay. 

References: 

American Dye Manufacturers Institute, Inc. (ADMI), 1974, "Dyes and the Environment: 

Reports on Selected Dyes and Their Effects," Vol. II, ADMI, New York. 

Au W, Pathak S, Colie CJ, Hsu TC. 1978. Cytogenetic toxicity of Gentian Violet and Crystal 

Violet on mammalian cells in vitro. Mutation Research 58:269-276. 

Au W, Butler MA, Bloom SE, Matney TS. 1979. Further study of the genetic toxicity of Gentian 

Violet. Mutation Research 66:103-112. 

Auer, C. M., Nabholz, J. V. and Baetcke, K. P., 1990, "Mode of Action and the Assessment of 

Chemical Hazards in the Presence of Limited Data: Use of Structure-Activity Relationships 

(SAR) under TSCA, Section 5," Environmental Health Perspectives, Vol. 87, pp. 183-197. 

Kier LD, Brusick DJ, Auletta AE. 1986. The Salmonella typhimurium/mammalian microsomal 

assay. A report of the U.S. Environmental Protection Agency Gene-Tox Program. Mutation 

Research 168:69-240. 

Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, vol. 23, pages 399-412. 

Little, L. W. and Lamb J. C., III, 1972. Acute Toxicity of 46 Selected Dyes to the Fathead 

Minnow, Pimephales promelas,Final Report to the American Dye Manufacturers Institute,Inc., 

UNC Wastewater Research Center, Department of Environmental Sciences and Engineering, 

School of Public Health, University of North Carolina, Chapel Hill, NC. 

Littlefield NA, Blackwell B-N, Hewitt CC, Gaylor DW. 1985. Chronic toxicity and 

carcinogenicity studies of Gentian Violet in mice. Fundamental and Applied Toxicology 5:902-

912. 

135

Mortelmans K, Haworth S, Lawlor T. 1986. Salmonella mutagenicity tests: II. Results from the 

testing of 270 chemicals. Environmental Mutagenesis 8(7):1-119. 

Nabholz, J. V., 1990. The OTS PMN ECOTOX Data Base: a Confidential Business Information 

(CBI) Collection of Environmental Toxicity Data from New Chemical Submissions Under Sec. 

5. Unpublished, Environmental Effects Branch, Health and Environmental Review Division 

(TS-796), U. S. Environmental Protection Agency, Washington, DC. 

NCTR Technical Report for Experiment Numbers 305,354,355. Three-generation reproduction 

and toxicity studies of Gentian Violet in Fischer 344 Rats. National Center for Toxicological 

Research. Jefferson, Arkansas. Sept. 1988. 

NCTR Technical Report for Experiment Number 355. Developmental toxicity study of Gentian 

Violet in Fischer 344 Rats. National Center for Toxicological Research. Jefferson, Arkansas. 

Sept. 1988. 

NTP. 1985. National Toxicology Program. C.I. Basic Red 9 monochloride. NTP TR-285. 

Sigman, C. C., Helms, C. T., Papa, P. A., Atkinson, D. L., Doeltz, M. K. and Winship-Ball, A., 

Jan. 1983. Anthraquinone Dyes and Related Chemicals: Review and Assessment of Potential 

Environmental and Health Aspects. Final Report to the Dyes Environmental and Toxicology 

Organization, Inc., SRI International, Menlo Park, CA. 

Sokolowska-Pituchowa J, Kowalczkowa J, Kus J, Piotrowski J, Sawicki B. 1965. Teratogenic 

effect of Malachite Green in experimental animals. Folia Biologica 13:311-315. 

Tonogai, Y., Ito, Y., Iwaida, M., Tati, M., Ose, Y. and Sato, T., 1979. Studies on the Toxicity of 

Coal-Tar Dyes. II. Examination of the Biological Reaction of Coal-Tar Dyes to Vital Body. The 

Journal of Toxicological Sciences, Vol. 4, pp. 211-219. 

July, 1994. 

136

Category: Vinyl Esters Human Health 

Environmental Toxicity 

(See “Esters”) 

Definition: A carboxylic acid ester with at least one vinyl group (CH2=CH-) attached to an 

organic acid radical (RCOO-). A simple vinyl ester is vinyl acetate: 

CH3COOCH=CH2 

Note: Certain carboxylic acid moieties themselves may exert toxicity such that there are 

concerns for effects in addition to those identified for the vinyl ester class. 

Hazard Concerns: Oncogenicity based on data from two bioassays: a 2-yr drinking water 

study of vinyl acetate in rats [significantly increased incidences of adenocarcinomas of the uterus 

and combined C-cell adenomas and carcinomas in high-dose (2,500 mg/l) female rats] and a 

chronic inhalation study of vinyl acetate in rats and mice (laryngeal/nasal tumors in rats, 

bronchiolar/alveolar adenomas in lungs of mice). There are supporting data from 27-mo and 81-

wk inhalation studies of acetaldehyde in rats and hamsters, respectively. Furthermore, 

mutagenicity data on these analogues support a cancer concern. Neurotoxicity based on data on 

an analogous PMN compound in rats plus suggestive data on vinyl acetate. Reproductive 

toxicity based on a two-generation study of vinyl acetate in rats. Environmental toxicity (see 

"Esters" category). 

Boundaries: Other than a requirement for a vinyl group and an acid group, none. 

General Testing Strategy 

(1) Up-front glove permeation study if there is a risk of any toxicity through dermal 

exposure. 

(2) Hydrolysis test (both acid- and enzyme-catalyzed) to determine the rate at which 

acetaldehyde, a potentially toxic metabolite, is released. [The requirement to measure 

acetaldehyde release is based on the assumption that acetaldehyde is the presumed "ultimate 

carcinogen" of vinyl esters. This requirement will be revisited as more decisive data become 

available. The hydrolysis data should be helpful in determining the most appropriate route of 

administration in the following tests.] 

(3) A 90-day neurotoxicity test in rats that includes a functional observational battery, 

motor activity tests, and neuropathology examinations. Also to be included, to address 

reproductive toxicity concerns, are the following adjuncts to the subchronic test: 

137

(a) Weights of the testes, epididymides (total and cauda), pituitary, seminal 

vesicles (with coagulating glands), prostate, ovary, and uterus are to be recorded at the time of 

sacrifice. 

(b) Histopathology of the testes is to be done on the males at the time of sacrifice. 

Particular attention is to be directed toward achieving satisfactory quality from fixation and 

embedding, and preparations are to follow the recommendations of Russell et al. (1990). 

Histologic analyses are to include evaluations of the spermatogenic cycle; i.e., the presence and 

integrity of the 14 cell states. These evaluations would follow the guidance provided by Russell 

et al. 

(4) A standard developmental toxicity study in rabbits and rats. 

(5) A 2-yr bioassay in rats and mice to address cancer concerns. 

(6) Environmental toxicity testing: see "Esters" category. 

References. 

Russell LD, Ettlin RA, Sinha Hikim AP, Clegg ED. 1990. Histological and histopathological 

evaluation of the testis. Cache River Press, Clearwater, FL. 

August, 1992 

138

Category: Vinyl Sulfones Human Health 

Environmental Toxicity 

Definition. Any molecular structure with a vinyl sulfone group is considered to be a member of 

the class: 

O


5

-S-CH=CH2 5

O


In addition the following is an example of a functional group that generates a vinyl sulfone under 

certain conditions. $-Sulfatoethyl-sulfonyl groups are typical vinyl sulfone precursors. 

Structures bearing this group are also members of the class: 

O


5 -
 -S-CH2-CH2-OSO3
 5

O


Typically, the new chemical of concern is a fiber-reactive dye bearing one or more vinyl 

sulfones, or vinyl sulfone precursors. Occupational exposure to workers via inhalation/ingestion 

of the powdered dye may pose a potential health risk. Under the conditions in a dye bath a vinyl 

sulfone precursor-containing dye generates the vinyl sulfone. In this scenario the only potential 

risk is to those who drink contaminated drinking water. However, following covalent binding of 

vinyl sulfone to textile fibers, survival of unbound vinyl sulfone substituents in the dye bath is 

low (< 10%). The majority of unbound vinyl sulfone is hydrolyzed to $-hydroxyethylsulfone. 

Unless releases to water are extremely high, vinyl sulfones are not expected to pose a significant 

risk to human health. Presently, there are no human health concerns for $-hydroxyethylsulfone. 

Hazard Concerns. For those who inhale or ingest a vinyl sulfone, there is an oncogenicity 

concern and mutagenicity concerns based on the potent mutagenicity of vinyl sulfone (VS) and 

methylvinyl sulfone (MVS). VS and MVS are mutagenic in the L5178Y TK+/- mouse lymphoma 

gene mutation assay in vitro. Evaluation of small colonies indicates that genotoxicity is due to a 

clastogenic mechanism. This is confirmed by evaluating the lymphoma cells for chromosome 

aberrations and micronuclei. MVS also induces effects upon the spindle apparatus in Chinese 

hamster lung cells in vitro, indicating an aneugenic (aneuploidy-inducing) activity. A directacting Michael addition-type reaction may be the mechanism of action. Although MVS and 

divinyl sulfone (DVS) are both reported as negative in vivo in the mouse micronucleus assay 

(inconclusive, only males tested), and in the dominant lethal assay, the Agency has determined 

that these negatives are not sufficient to remove concern for vinyl sulfone-containing new 

chemicals as potential mutagens and carcinogens. 

There are ecotoxicity concerns for VS only, based on concerns for electrophiles. 

139

Boundaries. There are at present no boundary conditions, related to health effects, for structures 

containing vinyl sulfones. Nearly all new chemicals in the category have been water-soluble, 

fiber-reactive dyes with molecular weights <1,000. The boundary conditions for ecotoxicity 

effects are molecular weights < 1000 and log Kow < 8. 

General Testing Strategy 

The New Chemicals Program considers the following tests to be appropriate to address health 

and ecotoxicity concerns: 

1. Mouse lymphoma assay with evaluation of small colonies (40 CFR 798.5300). The test 

would trigger a lifetime rodent bioassay if positive. 

2. Base-set ecotoxicity testing to include fish (40 CFR 797.1400), daphnids (40 CFR 

797.1300) and algae (40 CFR 797.1050). The acute toxicity tests for fish and daphnids will be 

done using the flow-through method with measured concentrations, and effective concentrations 

will be based on 100% active ingredients (AI) and mean measured concentrations. If there is 

insufficient knowledge about the water solubility of the dye, then it should also be measured (40 

CFR 796.1840 or 796.1860). 

If there is no significant risk from the PMN after the results of the fish and daphnid acute 

toxicity and algal toxicity tests have been integrated into the risk assessment, then no further 

testing is recommended. However, if there is a significant risk, then do environmental fate 

testing as outlined in 3. 

3. Environmental fate testing for releases to water. 

Tier 1. Direct and Indirect Photolysis Screening Test (40 CFR 796.3765). If t1⁄2 < 2 

days, go to Tier 2; if t1⁄2 > 2 days, go to Tier 3. 

Tier 2a. If t1⁄2 < 2 days and photolysis products are known and/or identified, then assess 

photolysis products for environmental hazards. 

Tier 2b. If t1⁄2 < 2 days and photolysis products are not known and/or identifiable, then 

prepare a stock solution of the PMN chemical using the standard humic-containing solution 

described in the direct and indirect photolysis screening test [40 CFR 796.3765 (b)(2) and 

(c)(2)], expose to sunlight for at least 6 half-lives (t1⁄2), and test photolysis products for toxicity 

with the most sensitive species from the environmental base set. 

140

Tier 3. Test for aerobic biodegradability according to any one of the following test 

guidelines: 

Modified Sturm Test 40 CFR 796.3260

Closed Bottle Test 40 CFR 796.3200

Modified OECD Screening Test 40 CFR 796.3240

Modified MITI Test (I) 40 CFR 796.3220

Modified AFNOR Test 40 CFR 796.3180

In addition, if appropriate, physical/chemical properties including:

Log Kow (40 CFR 796.1550, 796.1570, or 796.1720)

Vapor pressure (40 CFR 796.1950)

Boiling point (40 CFR 796.1220)

Melting point range (40 CFR 796.1300)

If the PMN chemical passes the aerobic biodegradability test according to the criteria set 

forth in the guidelines, no further testing may be recommended. A new risk assessment is 

conducted to determine if chronic ecotoxicity testing is warranted. 

4. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 CFR 

797.1600), with flow-through methods; measured concentrations; effective concentrations based 

on 100% AI and mean measured concentrations; and statistical analysis of effective 

concentrations at days 7, 14, 21, and 28. 

Daphnid chronic toxicity testing (40 CFR 797.1330), with flow-through methods; 

measured concentrations; effective concentrations based on 100% AI and mean measured 

concentrations; statistical analysis of effective concentrations at days 7, 14, and 21. 

5. Ecotoxicity testing for release to terrestrial ecosystems. 

The terrestrial base set of environmental toxicity tests (i.e., the early seedling growth test, 

the earthworm toxicity test and the soil microbial community bioassay) will be recommended for 

terrestrial exposures. Chronic toxicity testing for terrestrial organisms include: the plant whole 

life cycle test, the plant uptake test, and the soil microbial community bioassay. 

References: 

Dearfield, KL, K Harrington-Brock, CL Doerr, JR Rabinowitz, and MM Moore (1991). 

Genotoxicity in mouse lymphoma cells of chemicals capable of Michael addition. Mutagenesis 

6: 519-525. 

141

Heyna, J (1963). Reactive dyes containing vinylsulfonyl groups. Angew. Chem. Internat. 

Edit. 2(1): 20-23. 

Shelby, MD, GA Gutierrez-Espeleta, WM Generoso, and AF McFee (1991). Mouse dominant 

lethal and bone marrow micronucleus studies on methyl vinyl sulfone and divinyl sulfone. 

Mutation Research 250: 431-437. 

Warr, TJ, JM Parry, RD Callander, and J Ashby (1990). Methyl vinyl sulfone: A new class of 

Michael-type genotoxin. Mutation Research 245: 191-199. 

September, 1988; revised June, 1994 

142

Category: Soluble complexes of Zinc Environmental Toxicity 

Definition. This category includes all organic and inorganic soluble complexes of zinc, for 

example, zincates, organozincs, such as, dimethylzinc. Not included in this category are zinccomplexed acid dyes and strong ion pairs between zinc and anionic surfactants. There are no 

toxicity data for soluble complexes of zinc, therefore, the toxicity data for the free Zn++ ion will 

be used to predict aquatic toxicity. 

Hazard Concerns. Zinc produces acute toxicity to freshwater aquatic organisms over a range of 

concentrations from 90 to 58,100 ug/L and produces chronic toxicity over a range from 47 to 852 

ug/L. The acute to chronic ratio (ACR) for Zn has been set at 3 in the water quality criteria 

(WQC) document. Zinc concentrations from 30 to 21,600 ug/L have been shown to reduce the 

growth of various aquatic plants and algae appear to be the most sensitive group. 

Bioconcentration factors (as logarithms) for freshwater fish ranged from 1.7 to 2.6, and from 2.0 

to 3.1 for freshwater invertebrates. Zinc is an essential nutrient trace element which can be toxic 

at higher concentrations. While acute toxicity is affected by hardness, chronic toxicity is not 

affected. The freshwater criteria at an average hardness of 100 mg/L are 0.120 ug/L for acute 

exposures and 0.110 ug/L for chronic exposures; the saltwater criteria are 0.095 ug/L for acute 

exposures and 0.086 ug/L for chronic exposures. These criteria are based on toxicity 

information for the following Zn salts: sulfate, chloride, phosphate, and nitrate. 

General Testing Strategy 

To address ecotoxicity concerns, base set acute aquatic toxicity testing (algae: static method, 

daphnid and fish: flow-through method, all measured concentrations). 

April, 1990 

143

Category: Zirconium Compounds Environmental Toxicity 

Definition. This category includes inorganic salts of zirconium (Zr), complexes between Zr and 

organic acids, and organoZr compounds, i.e., Zr covalently-bonded with carbon. For example, 

some inorganic Zr salts include: Zr sulfate, Zr oxychloride, and Zr tetrachloride. Not included 

in this category are dyes complexed with Zr. 

Hazard Concerns. Soluble salts of Zr are known to be moderately toxic to green algae and fish 

based on exposures in soft water and in terms of mg Zr/L. Toxicity information are only 

available for Zr sulfate, Zr tetrachloride, and Zr oxychloride. The toxicity profile for Zr based 

on available toxicity data, mg Zr/L (ppm Zr), and moderate hardness (i.e., 150.0 mg/L as CaCO3) 

is: 

fish 96-h LC50 = 58.0 (n=3) 

green algal 96-h EC50 = 2.6 

Zirconium is more toxic in soft water than hard water. Acute toxicity to fish have been shown to 

increase 13 times as hardness decreases from 400.0 to 20 mg/L. 

Boundaries. The toxicity of Zr compounds depends on the their physical/chemical properties 

and the hardness of receiving waters. The toxicity of Zr salts and Zr complexes with organic 

acids are expected to be related to their water solubility and MW. The toxicity of organoZr 

compounds are also expected to be related to their octanol/water partition coefficient (Kow). 

The most important property determining the toxicity of Zr compounds is water solubility. 

Water solubility cannot be estimated accurately and has to be measured. The water solubility of 

organoZr compounds is expected to decrease as Kow increases. There is no lower bound for 

Kow and the upper bound cannot be determined at this time since the Kow fragment-constant for 

Zr is not known. In addition to solubility, MW is also an important boundary. Compounds with 

MWs > 1000 are not expected to be absorbed by aquatic organisms even if they are water 

soluble. Therefore, only Zr compounds with MWs < 1000 are expected to be toxic. 

General Testing Strategy 

I. Release to Aquatic Ecosystems 

Tier 1. The aquatic base set of environmental toxicity tests will be recommended for aquatic

exposures. The acute toxicity tests for fish (40 CFR §797.1400) and daphnids (40 CFR

§797.1300) will be done using the flow-through method; effective concentrations will be based

on 100% active ingredients (AI) and mean measured concentrations; the total organic carbon

(TOC) concentration of dilution water in the control must be less than 2.0 mg TOC/L; TOC

must be measured in the control just prior to

the start of the test; the highest treatment concentration on a nominal-basis should not exceed

the aqueous solubility limit of the tested compound; solvent can be used to assist the compound

to reach its aqueous solubility limit quicker, but cannot be used to artificially enhance the water

144

solubility of the compound beyond its aqueous solubility limit; and hardness of dilution water 

3. If toxicity mitigation testing is done with humic acid, 

then the static method with nominal concentrations will be recommended. 

has to be less than 180.0 mg/L as CaCO

The algal toxicity testing (40 CFR §797.1050), should be done with the static method; 

effective concentrations based on 100% AI and mean measured concentrations; statistical 

analysis of effective concentrations at 24, 48, 72, and 96 hours; test medium with no more than 

0.300 mg/L EDTA as a final concentration; the TOC of the test/growth medium should be less 

than 2.0 mg TOC/L; TOC should be measured just prior to the start of the test; the highest 

treatment concentration on a nominal-basis should not exceed the aqueous solubility limit of the 

tested compound; and solvent can be used to assist the compound to reach its aqueous solubility 

limit quicker, but cannot be used to artificially enhance the water solubility of the compound 

beyond its aqueous solubility limit. If toxicity mitigation testing is done with humic acid, then 

nominal concentrations will be recommended. 

If there is no significant risk from the Zr compound after the results of the environmental 

base set have been integrated into the risk assessment, then no further testing will be 

recommended. However, if there is a significant risk, then go to Tier 2. 

Tier 2. Fish chronic toxicity testing, i.e., fish early life stage (ELS) toxicity testing (40 

CFR §797.1600), with the flow-through method; effective concentrations based on 100% AI and 

mean measured concentrations; statistical analysis of effective concentrations at days 7, 14, 21, 

and 28; the TOC of dilution water in the control should be less than 2.0 mg TOC/L; TOC 

should be measured in the controls just prior to and during the test; the highest treatment 

concentration on a nominal-basis should not exceed the aqueous solubility limit of the tested 

compound; solvent can be used to assist the compound to reach its aqueous solubility limit 

quicker, but cannot be used to artificially enhance the water solubility of the compound beyond 

its aqueous solubility limit; and hardness of dilution water has to be less than 180.0 mg/L as 

CaCO3. 

Daphnid chronic toxicity testing (40 CFR §797.1330), with the flow-through method; 

effective concentrations based on 100% AI and mean measured concentrations; statistical 

analysis of effective concentrations at days 7, 14, and 21; the TOC of 

dilution water in the control should not exceed 2.0 mg TOC/L; TOC must be measured in the 

controls just prior to and during the test; the highest treatment concentration on a nominal-basis 

should not exceed the aqueous solubility limit of the tested compound; solvent can be used to 

assist the compound to reach its aqueous solubility limit quicker, but cannot be used to 

artificially enhance the water solubility of the compound beyond its aqueous solubility limit; 

and hardness of dilution water has to be less than 180.0 mg/L as CaCO3. 

II. Release to Terrestrial Ecosystems: The terrestrial base set of environmental toxicity tests 

will be recommended for terrestrial exposures. The terrestrial base set includes: the early 

seeding growth test (40 CFR 797.2800), the earthworm toxicity test (40 CFR.795.150), the soil 

microbial community bioassay (40 CFR 797.3700), and the avian acute oral toxicity test (40 

CFR 797.2175). Chronic toxicity testing for terrestrial organisms include: the plant whole life 

cycle test (40 CFR 797.xxxx), the plant uptake test (40 CFR 797.2850), and the avian 

reproduction test (40 CFR 797.2130 for bobwhite quail or 40 CFR 797.2150 for mallard duck). 

June, 1992 

145