![](media/image1.png) **UNITED STATES ENVIRONMENTAL PROTECTION AGENCY**

**WASHINGTON, DC 20460**

OFFICE OF

PREVENTION, PESTICIDES,

AND TOXIC SUBSTANCES

> July 12, 2006

**MEMORANDUM:**

**Subject:** Ecological Hazard and Environmental Risk Assessment of
alkylbenzene sulfonates for the Registration Eligibility Document (RED).
PC Codes: 190116; 079010; 098002

**To:** Heather A. Garvie, Chemical Review Manager

Antimicrobials Division

**From:** Richard C. Petrie, Agronomist, Team Leader

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510C)

**Thru:** Norm Cook, Branch Chief

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510C)

**DP Barcode: 330326**

**Decision No.: 362579**

**Case No.:** 4006

Chemical Name (s) CAS \#

Sodium Dodecylbenzene Sulfonate 25155-30-0

Benzenesulfonic acid, C10-16-alkyl derivatives (DDBSA) 68584-22-5

Dodecylbenzene sulfonic acid (DDBSA) 27176-87-0/68584-22-5

**ECOLOGICAL HAZARD AND ENVIRONMENTAL RISK ASSESSMENT**

**ALKYLBENZENE SULFONATES**

**CASE 4006**

**PC CODE: 190116**

**07/12/2006**

**Richard C. Petrie**

**Antimicrobials Division**

**Office of Pesticide Programs**

**U.S. Environmental Protection Agency**

**1200 Pennsylvania Avenue, NW**

**Washington, DC 20460**

Table of Contents

1\. Ecological Toxicity Data . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

A. Toxicity to Terrestrial Animals . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . 5

1\. Birds, Acute and Subacute . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 5

2\. Mammals, Acute and Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . 5

B. Toxicity to Aquatic Animals . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . 5

1\. Freshwater Fish, Acute . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 6

2\. Freshwater Invertebrates, Acute . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . 6

3\. Estuarine and Marine Organisms, Acute . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . 7

4\. Aquatic Organisms, Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . 8

C. Toxicity to Plants . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

II\. Risk Assessment and Risk Characterization . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

A. Environmental Fate Assessment Summary . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . 11

B. Environmental Exposure Assessment . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 11

C. Environmental Risk Assessment . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . 12

D. Endangered Species Considerations . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .12

E. Inert Ingredient Use.................... . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .14

III\. Confirmatory Data Required. . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

IV\. Label Hazard Statements for Terrestrial and Aquatic Organisms. . .
. . . . . . . . . . . . . . . . . . .. .14

V. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

**Ecological Effects Hazard and Environmental Risk Assessment**

**alkylbenzene sulfonates**

Alkylbenzene sulfonates are used for a variety of indoor antimicrobial
uses. Alkylbenzene sulfonates include sodium dodecylbenzene sulfonate,
dodecylbenzene sulfonic acid, and benzenesulfonic acid, and are
collectively called DDBSA by the DDBSA Joint Venture Task Force. All
alkylbenzene sulfonates as pesticides are formulated with phosphoric
acid (CAS#s 27276-87-0 and 68584-22-5; mineral acid RED -
EPA-738-93-025, December 1993). Alkylbenzene sulfonates through
sulfonation and neutralization becomes linear alkylbenzyl sulfonate
(LAS).

Currently registered use categories include spray application to
agricultural premises and equipment, food handling/storage establishment
premises and equipment, commercial-institutional-industrial premises and
equipment, medical premises and equipment. Sites include: milking
equipment, dairy farms, teat liners, farm utensils, milk claws and
inflations, bars, restaurants, dairy equipment, dairy premises, dairy
utensils, milk processing plant surfaces-equipment-premises, milk
storage, fruit and vegetable wash water, food/milk transport vehicles,
food processing plant equipment-handling-storage premises and surfaces,
bakery processing equipment, brewery process plant equipment and
surfaces, cannery processing equipment, potato washing machines, winery
processing equipment, egg processing equipment, beverage processing
equipment-premises and surfaces, meat and poultry processing
equipment-premises and surfaces, food vending and dispensing machines,
soft custard equipment, food stores/markets, seed houses, food service
industry pots and pans, research animal facilities, zoo premises,
airports, campgrounds, commercial transportation facilities, aircraft,
buses, ships, automobiles, railroad trains, shower stalls, urinals,
toilet bowls, sickroom premises, and healthcare facilities. There are no
home-owner or residential uses currently registered. The only outdoor
use, mine acid control, was voluntarily withdrawn by the registrant.

Approximately 300,000 pounds of alkylbenzene sulfonates are used in EPA
registered antimicrobial products, which is a small fraction of the
approximately 860 million pounds produced each year . The majority of
uses of alkylbenzene sulfonates are as household laundry and dish
detergents.

**I. Ecological Toxicity Data**

The toxicity endpoints presented below are based on the results of
ecotoxicity studies submitted to EPA to meet the Agency=s data
requirements for the uses of the alkylbenzene sulfonates. The linear
chained alkylbenzene sulfonates (LAS) replaced the highly persistent
branched alkylbenzene sulfonates (ABS) in the mid 1960\'s in laundry
detergents. The environmental fate and effects or LAS detergent
formulations on aquatic/terrestrial organisms are well studied (see
www.inchem.org and www.cler.com for detailed information). Ecotoxicity
data available for LAS is assumed to be representative of DDBSA based on
available literature.

> **A.** **Toxicity to Terrestrial Animals**

**(1)** **Birds, Acute and Subacute**

In order to establish the toxicity of alkylbenzene sulfonates to avian
species for environmental hazard labeling, the Agency requires an acute
oral toxicity study using the TGAI for outdoor uses having no
environmental exposure of concern. One avian acute test species is
required for indoor uses for label hazard purposes. Preferred test
species can be either the mallard duck (a waterfowl) or the Northern
bobwhite quail (an upland game bird). See Table 1 below for test
results.

**Table 1. Acute Oral Toxicity of sodium dodecylbenzene sulfonate to
Birds**

+--------------+----------+---------+---------+-------------+--------+
| **Species**  | **c      | **End   | **T     | **Satisfies | *      |
|              | hemical, | point** | oxicity | Gu          | *Refer |
|              | % Active |         | C       | idelines/** | ence** |
|              | In       | **(m    | ategory |             |        |
|              | gredient | g/kg)** | (       | *           |        |
|              | (ai)**   |         | TGAI)** | *Comments** |        |
+--------------+----------+---------+---------+-------------+--------+
| Northern     | 87.      | LD~50~  | S       | Yes.        | MRID:  |
| bobwhite     | 6%Carbon | \> 1382 | lightly | Acceptable. |        |
|              | chain    |         | toxic   |             | 41     |
| *(Colinus    | not      | NOEL =  |         | 14 day test | 143901 |
| v            | ide      | 279     |         |             |        |
| irginianus)* | ntified. |         |         |             |        |
|              | (        |         |         |             |        |
|              | Nacconal |         |         |             |        |
|              | 90G      |         |         |             |        |
|              | used)    |         |         |             |        |
+--------------+----------+---------+---------+-------------+--------+

The results indicate that LAS is slightly toxic to the Northern bobwhite
quail on an acute oral basis. The sodium dodecylbenzene sulfonate study
MRID 41143901 fulfills guideline requirement 850.2100. The avian acute
oral LD50 is \> 500 ppm, therefore, an avian environmental hazard
statement for birds is not required on manufacturing and end-use product
labels.

A subacute dietary study using the TGAI may be required on a
case-by-case basis depending on the results of lower-tier ecological
studies and pertinent environmental fate characteristics in order to
establish the toxicity of a chemical to avian species, however, this
testing is not required unless outdoor uses are added to alkylbenzene
sulfonate labels.

> **(2)** **Mammals, Acute and Chronic Toxicity**

In most cases, rat toxicity studies for human health risk assessments
are used as surrogates for wild mammal testing. Wild mammal tests are
not required for alkylbenzene sulfonates at this time because the
currently registered uses are indoor spray applications. Refer to the
toxicology section of this RED for mammalian toxicity data.

> **B.** **Toxicity to Aquatic Animals**
>
> **(1)** **Freshwater Fish, Acute**

In order to establish the acute toxicity of pesticides to freshwater
fish for environmental hazard labeling, the Agency requires a TGAI study
for indoor uses having no environmental exposure of concern. The
preferred test species are rainbow trout (a coldwater fish) or bluegill
sunfish (a warm water fish). Results of freshwater fish acute testing
for LAS are presented in Table 2.

**Table 2. Acute Toxicity of LAS to Freshwater Fish**

+-----------+-------+---------+-----------+--------------+-----------+
| **        | **%   | **Endp  | *         | **Satisfies  | **Re      |
| Species** | A     | oints** | *Toxicity | G            | ference** |
|           | ctive |         | C         | uidelines/** |           |
|           | Ingre | **      | ategory** |              |           |
|           | dient | (ppm)** |           | **Comments** |           |
|           | (     |         |           |              |           |
|           | ai)** |         |           |              |           |
+-----------+-------+---------+-----------+--------------+-----------+
| Fathead   | 14    | 96hr    | M         | Yes.         | 44260002  |
| Minnow    | .0%\* | LC50 =  | oderately | Supplemental |           |
| (*P       |       |         | toxic     | study.       |           |
| imephales |       | 3.4     |           |              |           |
| p         |       | mg/L    |           |              |           |
| romelas*) |       |         |           |              |           |
+-----------+-------+---------+-----------+--------------+-----------+
| Rainbow   | 65.0% | 96 hr   | M         | Yes.         | 44260009  |
| trout     |       | LC50 =  | oderately | Supplemental |           |
|           | C11,  |         | toxic     |              |           |
| (*Onco    | C12   | 1.68    |           | study.       |           |
| rhynchus* |       | mg/L    |           |              |           |
|           |       |         |           |              |           |
| *mykiss*) |       |         |           |              |           |
+-----------+-------+---------+-----------+--------------+-----------+

\* Carbon chain not identified.

The guideline requirement for a freshwater fish acute test has been
fulfilled. In addition the LAS SIAR reports 11 acute freshwater fish
studies using commercially relevant LAS and LAB formulations. The LC50
values range from 1.67 to 7.7 mg/L. Data using LAB sulfonic acids in the
LAS SAIR report range in toxicity from 3.0 to 10.0 mg/L. Research by
Fairchild et al. (1993) indicates that "Degradation processes rapidly
reduce chain lengths of LAS in the environment to averages lower than
C12. Thus, hazard assessments of LAS to aquatic organisms should focus
on environmentally relevant mixtures of average chain lengths of C12 or
less." Based on study results above (MRIDs 44260002, 44260009) and
studies presented in LAS SIAR, an environmental hazard statement for
fish is not required on manufacturing and end-use product labels under
consideration in this RED.

> **(2)** **Freshwater Invertebrates, Acute**

In order to establish the acute toxicity of pesticides to freshwater
aquatic invertebrates for environmental hazard labeling, the Agency
requires a TGAI study for indoor uses having no environmental exposure
of concern. The preferred test species is *Daphnia magna*. See Table 3
below for results of available studies for LAS.

**Table 3. Acute Toxicity of LAS to Freshwater Invertebrates**

+------------+---------+---------+-----------+-------------+---------+
| *          | **%     | **Endp  | *         | **Satisfies | **Refe  |
| *Species** | Active  | oints** | *Toxicity | Gu          | rence** |
|            | Ing     |         | C         | idelines/** |         |
|            | redient | **      | ategory** |             |         |
|            | (ai)**  | (ppm)** |           | *           |         |
|            |         |         |           | *Comments** |         |
+------------+---------+---------+-----------+-------------+---------+
| Waterflea  | Not     | 48-hr.  | []{.mark} | []{.mark}   | 4       |
|            | re      | EC~50~  |           |             | 7025025 |
| *(Daphnia  | ported. | =       | C-12 =    | Yes.        |         |
| magna)*    |         | LAS-C10 | m         | S           |         |
|            |         | = 29.5  | oderately | upplemental |         |
|            |         | mg/L,   | toxic.    | study.      |         |
|            |         | LAS-C12 |           |             |         |
|            |         | = 6.84  | []{.mark} |             |         |
|            |         | mg/L,   |           |             |         |
|            |         | LAS-C14 |           |             |         |
|            |         | = 0.80  |           |             |         |
|            |         | mg/L,   |           |             |         |
|            |         | LAS-C16 |           |             |         |
|            |         | = 0.20  |           |             |         |
|            |         | mg/L.   |           |             |         |
+------------+---------+---------+-----------+-------------+---------+

The results of this study indicate that LAS toxicity to Daphnia magna is
variable, dependent on the length of the carbon chain. LAS/SIAR (page
37) summarizes 11 *Daphnia* magna studies on commercially relevant LAS
that range in EC50 values from 1.62 to 9.3 mg/L. Data on the LAB
sulfonic acids give EC50 values for *Daphnia* magna ranging from 2.9 to
12 mg/L. Formulations tested included the C10-C16 b3enzene sulfonic acid
and the dodecylbenzene sulfonic acid. Even though the higher carbon
chains are more toxic, the CLER (Council for LAB/LAS Environmental
Research) ensures that the typical LAS or LAB formulations contain less
than 1 - 10% carbon chains C14 or greater. The LAS SIAR report cites 11
*Daphnia magna* studies on commercial LAS formulations with EC50 values
ranging from 1.62 to 9.3 mg/L. LAB formulations ranged in toxicity from
2.9 to 12 mg/L. Research by Fairchild et al. (1993) states: "Degradation
processes rapidly reduce chain lengths of LAS in the environment to
averages lower than C12. Thus, hazard assessments of LAS to aquatic
organisms should focus on environmentally relevant mixtures of average
chain lengths of C12 or less." Based on study results above (MRID
47025025) and studies presented in LAS SIAR, an environmental hazard
statement for aquatic invertebrates is not required on manufacturing and
end-use product labels under consideration in this RED.

> **(3)** **Estuarine and Marine Organisms, Acute**

Acute toxicity testing with estuarine and marine organisms using the
TGAI is required when the end-use product is intended for direct
application to the marine/estuarine environment or effluent containing
the active ingredient is expected to reach this environment. Acute
estuarine/marine tests are not required for alkylbenzene sulfonates
because the currently registered uses are indoor applications.

**(4) Aquatic Organisms, Chronic**

Chronic toxicity testing (Fish early life stage, 850.1300/72-4a and
aquatic invertebrate life cycle, 850.1400/72-4b) is required for
pesticides when certain conditions of use and environmental fate apply.
Chronic aquatic organism tests are not required for alkylbenzene
sulfonates because the currently registered uses are indoor
applications. The chronic NOAEC toxicity value from the 28 day study for
fathead minnow using carbon chain C11.7 was 0.7 mg/L (Fairchild et al,
1993).

**C**. **Toxicity to Plants**

Non-target plant phytotoxicity tests are required for pesticides when
uses result in exposure to the environment. This testing is not required
for alkylbenzene sulfonates because the currently registered uses are
indoor applications. Refer to Table 4 below for the summary of a
non-target plant phytotoxicity study using green algae.

**Table 4. Acute Toxicity of LAS to Green Algae**

+-----------+-----------+-----------+-----------+-----------+-----------+
| **        | **%       | **En      | **T       | **        | **Re      |
| Species** | active    | dpoints** | oxicity** | Satisfies | ference** |
|           | ing       |           |           | Guid      |           |
|           | redient** | **(ppm)** | **C       | elines/** | **MRID:** |
|           |           |           | ategory** |           |           |
|           | **(ai)**  |           |           | **C       |           |
|           |           |           |           | omments** |           |
+-----------+-----------+-----------+-----------+-----------+-----------+
| *Sel      | Not       | 96 hr.    | Slightly  | No.       | 42439803  |
| enastrum* |           | EC50 =    |           | Supp      |           |
|           | Reported. |           | Toxic     | lemental. |           |
| *capri    | Carbon    | 70.27     |           |           |           |
| cornutum* | chain not |           |           |           |           |
|           | id        |           |           |           |           |
|           | entified. |           |           |           |           |
+-----------+-----------+-----------+-----------+-----------+-----------+

**II. Risk Assessment and Characterization**

Risk assessment integrates the results of the exposure and ecotoxicity
data to evaluate the likelihood of adverse ecological effects. One
method of integrating the results of exposure and ecotoxicity data is
called the quotient method. For this method, risk quotients (RQs) are
calculated by dividing exposure estimates by ecotoxicity values, both
acute and chronic:

RQ = EXPOSURE/TOXICITY

RQs are then compared to OPP\'s levels of concern (LOCs). These LOCs are
criteria used by OPP to indicate potential risk to nontarget organisms
and the need to consider regulatory action. The criteria indicate that a
pesticide used as directed has the potential to cause adverse effects on
nontarget organisms. LOCs currently address the following risk
presumption categories: (1) **acute high** - potential for acute risk is
high, and regulatory action may be warranted in addition to restricted
use classification; (2) **acute restricted use** - the potential for
acute risk is high, but this may be mitigated through restricted use
classification; (3) **acute endangered species** - the potential for
acute risk to endangered species is high, and regulatory action may be
warranted; and (4) **chronic risk** - the potential for chronic risk is
high, and regulatory action may be warranted. Currently, AD does not
perform assessments for chronic risk to plants, acute or chronic risks
to nontarget insects, or chronic risk from granular/bait formulations to
mammalian or avian species.

The ecotoxicity test values (i.e., measurement endpoints) used in the
acute and chronic risk quotients are derived from the results of
required studies. Examples of ecotoxicity values derived from the
results of short-term laboratory studies that assess acute effects are:
(1) LC~50~ (fish and birds) (2) LD~50~ (birds and mammals) (3) EC~50~
(aquatic plants and aquatic invertebrates) and (4) EC~25~ (terrestrial
plants). Examples of toxicity test effect levels derived from the
results of long-term laboratory studies that assess chronic effects are:
(1) LOEC (birds, fish, and aquatic invertebrates) (2) NOEC (birds, fish
and aquatic invertebrates) and (3) MATC (Maximum Allowable Toxic
Concentration) (fish and aquatic invertebrates). For birds and mammals,
the NOEC value is used as the ecotoxicity test value in assessing
chronic effects. Other values may be used when justified. Generally, the
MATC (defined as the geometric mean of the NOEC and LOEC) is used as the
ecotoxicity test value in assessing chronic effects to fish and aquatic
invertebrates. However, the NOEC is used if the measurement endpoint is
production of offspring or survival.

Risk presumptions, along with the corresponding RQs and LOCs are
tabulated below.

  -----------------------------------------------------------------------
  **Risk Presumptions for Terrestrial Animals**
  -----------------------------------------------------------------------

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

  ------------------------------------------------------------------------
  Risk Presumption         RQ                                    LOC
  ------------------------ ------------------------------------- ---------

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

  -----------------------------------------------------------------------
  **Birds and Wild Mammals**

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

  ------------------------ ------------------------------------- ---------
  Acute High Risk          EEC^1^/LC~50~ or LD~50~/sqft^2^ or    0.5
                           LD~50~/day^3^                         

  Acute Restricted Use     EEC/LC~50~ or LD~50~/sqft or          0.2
                           LD~50~/day (or LD~50~ \< 50 mg/kg)    

  Acute Endangered Species EEC/LC~50~ or LD~50~/sqft or          0.1
                           LD~50~/day                            

  Chronic Risk             EEC/NOEC                              1
  ------------------------ ------------------------------------- ---------

^1^ abbreviation for Estimated Environmental Concentration (ppm) on
avian/mammalian food items

^2^ [mg/ft^2^]{.underline} ^3^ [mg of toxicant consumed/day]{.underline}

LD~50~ \* wt. of bird LD~50~ \* wt. of bird

  -----------------------------------------------------------------------
  **Risk Presumptions for Aquatic Animals**

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

  ------------------------------- ------------------------------ --------
  Risk Presumption                RQ                             LOC

  Acute High Risk                 EEC^1^/LC~50~ or EC~50~        0.5

  Acute Restricted Use            EEC/LC~50~ or EC~50~           0.1

  Acute Endangered Species        EEC/LC~50~ or EC~50~           0.05

  Chronic Risk                    EEC/MATC or NOEC               1
  ------------------------------- ------------------------------ --------

^1^ EEC = (ppm or ppb) in water

  ------------------------------- ------------------------------ --------
  **Risk Presumptions for                                        
  Plants**                                                       

  Risk Presumption                RQ                             LOC
  ------------------------------- ------------------------------ --------

+-----------------------------------------------------------------------+
| ## Terrestrial and Semi-Aquatic Plants                                |
+-----------------------------------------------------------------------+

  ------------------------------- ------------------------------ --------
  Acute High Risk                 EEC^1^/EC~25~                  1

  Acute Endangered Species        EEC/EC~05~ or NOEC             1
  ------------------------------- ------------------------------ --------

+-----------------------------------------------------------------------+
| ## Aquatic Plants                                                     |
+-----------------------------------------------------------------------+

  ------------------------------- ------------------------------ --------
  Acute High Risk                 EEC^2^/EC~50~                  1

  Acute Endangered Species        EEC/EC~05~ or NOEC             1
  ------------------------------- ------------------------------ --------

^1^ EEC = lbs ai/A

^2^ EEC = (ppb/ppm) in water

> **A. Environmental Fate Assessment Summary (excerpted from the
> Environmental Fate Science Chapter of this RED document)**

No fate studies for DDBSA are available in US EPA's files. It was
decided by the agency during Phase IV or reregistration that data in the
open literature would be utilized in the DDBSA environmental fate
assessment. The EPI Suite model was run to obtain different
environmental properties for DDBSA\'s. These values are provided in
Section 3.0, "Model Results**."** The output parameters model support
that any potential impacts are expected to be very short-lived. This is
because the chemical is not likely to persist in water or microbial
soils and sediments. The Agency also conducted a literature search to
further support the output parameters that were provided by the EPI
Suite model. The results of the literature search are presented in
Section 4.0, "Additional Data from Literature Search."

Sodium dodecylbenzene sulfonate is highly unlikely to bioaccumulate in
the environment or aquatic organisms (i.e. fish) because the low value
for the log Kow (3). The chemical is also expected to be soluble in
water such that it will exhibit mobility through the soil. In addition,
the low log Koc (4.2261) further supports the expected soil mobility.
The model-calculated linear and non-linear biodegradation probabilities
suggest that the linear carbon chain will biodegrade rapidly, whereas
the benzene ring is not expected to biodegrade as rapidly. The short
half life of approximately 7.914 hours indicates that if this chemical
is present in the soil, it is not likely to be volatile and is expected
to degrade rapidly.

DDBSA is expected to behave very similarly as what is projected for
sodium dodecylbenzene sulfonate. Based on the low Kow value (3.80),
DDBSA is highly unlikely to bioaccumulate in the environment or aquatic
organisms (i.e. fish). The chemical is also expected to be soluble in
water such that it will exhibit mobility through the soil. In addition,
the log Koc (3.6944) is low, and this further supports the expected soil
mobility. The model-calculated linear and non-linear biodegradation
probabilities suggest that the chemical will most likely biodegrade
rapidly. The short half life of approximately 9.485 hours indicates that
this chemical is not likely to be volatile from soils and is expected to
degrade rapidly.

As a result of the modular output along with the information gathered
from the literature search, the environmental fate of alkylbenzene
sulfonates is not likely to be of a concern. Likewise, minimal or no
environmental exposure is expected to occur from the majority of
alkylbenzene sulfonate antimicrobial pesticide uses because it is
unlikely that any appreciable exposure to terrestrial or aquatic
organisms would occur. This is assumed based on the information that a
very small number of pounds of this chemical are sold for commercial
down-the-drain use.

**B. Environmental Exposure Assessment**

Environmental exposure modeling was not conducted for alkylbenzene
sulfonic acids and sulfonates because the currently registered uses are
indoor spray applications. Uses such as urinals and toilet bowls could
result in minimal exposure to the environment when flushed. However,
significant environmental exposure is not expected for the following
reasons: 1.) total LAS usage for these industrial applications is very
minor - a very small percentage of the total pounds used in
antimicrobials; and commercial only use precludes broad environmental
exposures that might occur with residential use, applications are mostly
sprayed on and allowed to air dry 2.) LAS breakdown and degradation in
the environment is very rapid, 3.) LAS is significantly reduced by
sewage treatment. Industrial water treatment requires a NPDES permit in
order to discharge effluents.

> **C. Environmental Risk Assessment**

Linear alkyl benzene sulfonates (LAS) have been the principal ingredient
in laundry detergent for 30+ years. Volume 12 (10) of the 1993 issue of
Environmental Toxicology and Chemistry featured a series of papers on
environmental impacts of LAS in a special symposium: Surfactants and
Their Environmental Safety - convened by R.A. Kimerle, N.T. De Oude and
T.W. La Point. Two papers provide excellent summaries of ecotoxicity
endpoints from literature, and feature laboratory vs field analysis of
detergent generated LAS impacts on aquatic organisms. An assessment of
short and long-term impacts of LAS detergents on the environment was
conducted. Monitoring indicates that concentrations of 0.230 mg/L
(continuous criterion concentration) and 0.625 mg/L (criterion maximum
concentration) are rarely exceeded in aquatic systems protected by
activated sludge treatment systems. Ecotoxicity studies indicate that a
laboratory derived NOAEC value of 0.40 mg/L LAS is protective of
structure and function of experimental streams. Mortality was determined
more sensitive than growth as a chronic endpoint in chronic fathead
minnow (*Pimephales promelas*) studies. The chronic NOAEC toxicity value
from the 28 day study for fathead minnow using carbon chain C11.7 was
0.7 mg/L (Fairchild et al, 1993). In a second symposia study, the in
situ toxicity of LAS to natural periphyton communities before and after
wastewater treatment was assessed. Upstream and downstream algal
communities were evaluated before and after the introduction of LAS into
the stream. LAS inhibitory effect levels were higher (3.3 mg/L) than
average levels recorded in wastewater treatment plant outflows in the
U.S. (0.115 average). Increases and decreases in periphyton community
abundance were observed, but determined not to be significant for the
three major species evaluated: *Amphora perpusilla, Navicula minima, and
Schizothrix calcicola* (Lewis et al, 1993).

No environmental exposure is expected to occur from the majority of
linear alkylbenzene sulfonate uses and it is unlikely that any
appreciable exposure to terrestrial or aquatic organisms would occur
from limited commercial down-the-drain use because of the very small
number of pounds sold for these uses as compared to the detergent market
and rapid degradation.

**D. Endangered Species Considerations**

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2),
requires all federal agencies to consult with the National Marine
Fisheries Service (NMFS) for marine and andronomus listed species, or
the United States Fish and Wildlife Services (FWS) for listed wildlife
and freshwater organisms, if they are proposing an \"action\" that may
affect listed species or their designated habitat. Each federal agency
is required under the Act to insure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence
of a listed species or result in the destruction or adverse modification
of designated critical habitat. To jeopardize the continued existence of
a listed species means \"to engage in an action that reasonably would be
expected, directly or indirectly, to reduce appreciably the likelihood
of both the survival and recovery of a listed species in the wild by
reducing the reproduction, numbers, or distribution of the species.\" 50
C.F.R. \' 402.02.

To facilitate compliance with the requirements of the Endangered Species
Act subsection (a)(2) the Environmental Protection Agency, Office of
Pesticide Programs has established procedures to evaluate whether a
proposed registration action may directly or indirectly reduce
appreciably the likelihood of both the survival and recovery of a listed
species in the wild by reducing the reproduction, numbers, or
distribution of any listed species (U.S. EPA 2004). After the Agency=s
screening-level risk assessment is performed, if any of the Agency=s
Listed Species LOC Criteria are exceeded for either direct or indirect
effects, a determination is made to identify if any listed or candidate
species may co-occur in the area of the proposed pesticide use. If
determined that listed or candidate species may be present in the
proposed use areas, further biological assessment is undertaken. The
extent to which listed species may be at risk then determines the need
for the development of a more comprehensive consultation package as
required by the Endangered Species Act.

For certain use categories, the Agency assumes there will be minimal
environmental exposure, and only a minimal toxicity data set is required
(Overview of the Ecological Risk Assessment Process in the Office of
Pesticide Programs U.S. Environmental Protection Agency - Endangered and
Threatened Species Effects Determinations, 1/23/04, Appendix A, Section
IIB, pg.81). Chemicals in these categories therefore do not undergo a
full screening-level risk assessment, and are considered to fall under a
Ano effect@ determination. The active ingredient uses of alkylbenzene
sulfonic acids and sulfonates fall into this category for the following
reasons:

1.  The amount that will actually reach the environment is very small
    based on usage data for down-the-drain uses.

2.  Use for toilets and urinals is limited (no home-owner or residential
    uses are registered).

3.  Breakdown of LAS in the environment and via sewage treatment is
    rapid and well documented in the literature.

The labeled antimicrobial uses of alkylbenzene sulfonic acids and
sulfonates are not expected to result in significant environmental
exposure. Therefore, no adverse effects (NE) to listed species are
anticipated.

**E.** **Inert Ingredient Use**

[]{.mark}

The alkylbenzene sulfonates are used as \"inert\" ingredients in
agricultural herbicide formulations. Preplant incorporated and
preemergence herbicide treatments are typically applied once per year to
the tilled, minimally tilled or no-tilled field before planting or
before crop emergence in the spring. Spray applications are primarily
via ground spray boom and occasionally by aircraft if a wet spring.
Movement of the alkylbenzene sulfonates from the treated field to the
aquatic environment can occur at the time of application due to spray
drift, or following application via surface water/soil flow or by
percolation to groundwater. The FIRST model has predicted a maximum
potential concentration of 6.6 ppb alkylbenzene sulfonates in drinking
water from inert agricultural uses (memo from K. Leifer, 2006).
Available modeling and literature suggest that these chemicals will most
likely biodegrade rapidly in soil due to microbial degradation.

The inert agricultural uses of alkylbenzene sulfonates are not expected
to adversely affect avian or mammalian species on an acute or chronic
basis. Aquatic organisms are also not expected to be adversely affected
by inert alkylbenzene sulfonates use acutely or chronically due to the
low predicted level of alkylbenzene sulfonates in water by FIRST. A
chronic freshwater fish toxicity test NOAEC of 400 ug/L alkylbenzene
sulfonates is considered protective of ecosystem structure and function
in experimental streams. Therefore, the predicted concentration of 6.6
ug/L in water is well below our chronic Level of Concern (LOC).

**III. Confirmatory Data Required -- N/A**

**IV. Label Hazard Statements for Terrestrial and Aquatic Organisms**

Manufacturing and end-use products must state:

\"Do not discharge effluent containing this product into lakes, streams,
ponds, estuaries, oceans, or other waters unless in accordance with the
requirements of a National Pollutant Discharge Elimination System
(NPDES) permit and the permitting authorities are notified in writing
prior to discharge. Do not discharge effluent containing this product to
sewer systems without previously notifying the local sewage treatment
plant authority. For guidance contact your State Water Board or Regional
Office of the EPA.\"

**V. REFERENCES**

MRID 41143901 - Lloyd, D.; Grimes, J.; Jaber, M. (1989) Nacconol 90G: An
Acute Oral Toxicity Study with the Bobwhite: Final Report: Wildlife
International Ltd. Project No. 257-101. Unpublished study prepared by
Wildlife International Ltd. 26p.

MRID 42439803 - Bollman, M.A. et. al. (1990) Report on the Algal
Toxicity Tests of Selected Office of Toxic Substances (OTS) Chemicals.
US EPA Environmental Research Laboratory. 179p.

MRID 44260002 - McKim, J. M.; Arthur, J.W.; Thorslund, T.W. (1975)
Toxicity of Linear Alkylate Sulfonate Detergent to Larvae of Four
Species of Freshwater Fish. USEPA, Nat. Water Qual. Lab., Duluth, MN.
Bulletin of Environmental Contamination and Toxicology. Vol 14 (1) pg.
1-7.

MRID 44260009 - Calamari, D.; Marchetti, R. (1973) The Toxicity of
Mixtures of Metals and Surfactants to Rainbow Trout (*Salmo gairdneri
rich*.) Water Research. Vol. 7(10) pg. 1453-1464.

MRID 47025025 - Maki, A.W.; Bishop, W.E. (1979) Acute Toxicity Studies
of Surfactants to *Daphnia magna* and *Daphnia pulex*. Archives of
Environmental Contamination and Toxicology. Vol. 8, p. 599-612.
Sponsored by The Proctor and Gamble Company USA, Ivorydale Technical
Ctr., Cincinnati, OH.

Fairchild, J. F., F. J. Dwyer, T. W. La Point, S. A. Burch, and C. G.
Ingersoll. 1993. Evaluation of a Laboratory-Generated NOEC For Linear
Alkylbenzene Sulfonate In Outdoor Experimental Streams. Environmental
Toxicology and Chemistry. Vol. 12(10): 1763-1775. Symposium on
Surfactants and Their Environmental Safety, 11th Annual Meeting, Society
of Environmental Toxicology and Chemistry, Arlington, VA, Nov. 11-15,
1990.

Lewis, M.A., C.A. Pittinger, D.H. Davidson and C.J. Ritchie. 1993. In
Situ Response of Natural Periphyton To An Anionic Surfactant And An
Environmental Risk Assessment For Phytotoxic Effects. Environmental
Toxicology and Chemistry. Vol. 12(10): 1803-1812. Symposium on
Surfactants and Their Environmental Safety, 11th Annual Meeting, Society
of Environmental Toxicology and Chemistry, Arlington, VA, Nov. 11-15,
1990.

OECD SIDS Initial Assessment Report (SIAR). 2005. April. Linear
Alkylbenzene Sulfonate (LAS).