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Problem Formulation for the 

Ecological Risk and Drinking Water Exposure 

Assessments 

in Support of the Registration Review of Dioctyl 

Sodium Sulfosuccinate (DSS) 

Dioctyl Sodium Sulfosuccinate (CAS 577-11-7) 

sodium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate

Prepared by:

Stephen Carey, Biologist 

William P. Eckel, Ph.D. Senior Science Advisor

U. S. Environmental Protection Agency 

Office of Pesticide Programs 

Environmental Fate and Effects Division 

Environmental Risk Branch III 

1200 Pennsylvania Ave., NW 

Mail Code 7507P 

Washington, DC 20460

Reviewed by: 

Mark Corbin, Branch Chief 

Date:

December 20, 2010 

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Table of Contents 

I. Purpose of Problem Formulation .......................................................................................... 4

II. Nature of Regulatory Action ................................................................................................... 4

A. DSS Regulatory History................................................................................................... 45

1. Nature of the Chemical Stressor ...................................................................................... 5

2. Overview of Pesticide Usage ............................................................................................. 6

IV. Receptors ............................................................................................................................. 67

1. Aquatic and Terrestrial Effects ........................................................................................ 67

2. Ecosystems Potentially at Risk ..................................................................................... 89

V. Assessment Endpoints ........................................................................................................... 89

VI. Conceptual Model ............................................................................................................ 89

1. Risk Hypothesis .......................................................................................................... 910

2. Conceptual Diagram ................................................................................................... 910

VII. Analysis Plan Options ................................................................................................ 1011

1. Measures of Effects and Exposure ................................................................................. 1011

VIII. Endangered Species Assessment .................................................................................. 1415

IX. Drinking Water Assessment ............................................................................................ 1516

X. Clean Water Act ................................................................................................................ 1516

XI. Anticipated Data Needs ................................................................................................... 1516

XII. Open Literature ............................................................................................................... 1617
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I. Purpose of Problem Formulation 

The purpose of this problem formulation is to provide the foundation for the ecological 

risk assessment being conducted for dioctyl sodium sulfosuccinate (DSS). As such, it articulates 

the purpose and objectives of the risk assessment, evaluates the nature of the problem, and 

provides a plan for analyzing the data and characterizing the risk (EPA, 1998). 

II. Nature of Regulatory Action 

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), all pesticides 

sold or distributed in the United States generally must be registered by the Environmental 

Protection Agency (EPA). In determining whether a pesticide can be registered in the U.S., EPA 

evaluates its safety to non-target species based on a wide range of environmental and health 

effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act (FQPA), and 

EPA was mandated to implement a new program for the periodic review of pesticides, i.e., 

registration review (http://www.epa.gov/oppsrrd1/registration_review/). The registration review 

program is intended to ensure that, as the ability to assess risk evolves and as policies and 

practices change, all registered pesticides continue to meet the statutory standard of no 

unreasonable adverse effects to human health and the environment. Changes in science, public 

policy, and pesticide use practices will occur over time. Through the new registration review 

program, the Agency periodically reevaluates pesticides to make sure that as change occurs, 

products in the marketplace can be used safely. 

As part of the implementation of the new Registration Review program pursuant to 

Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the Agency is 

beginning its evaluation of dioctyl sodium sulfosuccinate (DSS) to determine whether it 

continues to meet the FIFRA standard for registration. This problem formulation for the 

environmental fate, ecological risk, and endangered species assessment chapter in support of the 

registration review will be posted in the initial docket opening the public phase of the review 

process. 

A. DSS Regulatory History 

Dioctyl sodium sulfosuccinate (DSS) is used as an active ingredient as well as an inert 

ingredient. As an active ingredient, there are no food uses. However, as an inert ingredient there 

are exemptions from the requirement of a tolerance established for the sodium salt of DSS under 

40 CFR 180.910 and 180.930. These exemptions allow DSS as an inert ingredient to be used in 

pesticide formulations for pre- and post-harvest application to crops and direct application to 

livestock. DSS is listed as the active ingredient in shampoos and spray pet products, which are 

registered in combination with undecylenic acid (PC 085501). Dioctyl sodium sulfosuccinate is 

used as an inert ingredient in multiple end-use pesticide products for agricultural and nonagricultural areas; in disinfectants and sanitizers used in residential and commercial settings; and 

as a wetting agent in industrial, drug, cosmetic, and food products. Some of the drug products 

contain DSS for use as a stool softener and laxative. 
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Toxicity information for DSS is largely from literature studies; most guideline toxicity 

studies are not available, and have been previously waived (except acute studies) by the Office of 

Pesticide Programs (OPP) because of its low toxicity. 

DSS has previously been evaluated as an inert ingredient (June 30, 2006). That review 

did not identify any ecological risks of concern. 

III. Stressor Source and Distribution 

 1. Nature of the Chemical Stressor 

Table III.1. Nature of the Chemical Stressor 

Common name Dioctyl sodium sulfosuccinate 

Chemical name Butanedioic acid, sulfo-, 1,4-bis(2-ethylhexyl) 

ester,sodiurn salt 

Pesticide type Insecticide, also inert ingredient 

Chemical class Anionic surfactant 

CAS number 577-11-7 

Empirical formula C20-H38-O7-S.Na 

Molecular mass (g/mol) 445.56 

Vapor pressure 2.17X10-11 mm Hg at 25 deg C (est.) 

Henry’s Law Constant (atm-m3/mol) 5X10-12 atm-cu m/mole (est.) 

Solubility in water (g/L) 15,000 mg/L @ 25°C 

Log Kow 3.95 (est.) 

pKa/pKb Anionic at ambient pH 

Log Koa (octanol-air partition coefficient) 13.6 (est.) 

Koc (organic carbon normalized partition 

coefficient) 

760 – 952 L/kg (est.) 

Hydrolysis half-life 6.65 years (pH 7) (est.) 

243 days (pH 8) (est.) 

Bioconcentration factor 56.23 L/kg wet-wt. (est.) 

Note: property estimates are from EpiSuite run for CAS Reg. No.577-11-7 

Environmental Fate/Exposure Summary: 

According to the Hazardous Substances Databank (HSDB) profile 

(http://toxnet.nlm.nih.gov/. accessed 8/13/2010), the use of Bis(2-ethylhexyl)sodium 

sulfosuccinate (DSS) as a wetting agent and food additive may result in its release to the 

environment through various waste streams. If released to soil, the expected mobility of DSS is 

low to very high. If released to water, DSS will be essentially nonvolatile. DSS has estimated 

aqueous base-catalyzed hydrolysis half-lives of 243 days at pH of 8 and 6.7 years at pH of 7. 

Aquatic bioconcentration is not expected to be an important fate process although adsorption to 

sediment may be possible. Several studies have shown that DSS biodegrades rapidly. A 

laboratory study of the degradation of DSS in activated sewage sludge indicates a half-life of 

about 15 days (US Testing, 1991). If released to the atmosphere, DSS will exist primarily in the 

particulate phase. In the vapor phase, it will degrade in the atmosphere by reaction with 

photochemically produced hydroxyl radicals with an estimated half-life of 18 hours. Physical 
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removal from air can occur through wet and dry deposition. Exposure to DSS can occur through 

dermal contact, inhalation, and ingestion. 

No degradates of concern have been identified for DSS, because no 40 CFR part 158 

environmental fate guideline studies have been submitted. However, ester hydrolysis should 

produce octanol and sulfosuccinic acid, both of which should be readily biodegradable and are 

not expected to be of toxic concern.

 2. Overview of Pesticide Usage 

DSS is used as an active ingredient (anionic surfactant) in pet shampoos, and as an inert 

ingredient in food-use products, in which it is exempt from the requirement of a tolerance. DSS 

has a human pharmaceutical use as a stool softener and laxative (known as docusate sodium), 

and is generally recognized as safe (GRAS) by the Food and Drug Administration (FDA). DSS 

has numerous other uses, such as a wetting agent in industrial, pharmaceutical, cosmetic, and 

food applications, as a dispersing and solubilizing agent in foods, and as an adjuvant in tablet 

formation (Merck Index, 1983). 

DSS is also used in oil-spill dispersing agents, such as Corexit 9500A (Nalco Energy 

Services, L.P.). 

The use of DSS in food-use agricultural pesticide formulations, and as a pet shampoo, as 

well as its numerous industrial and consumer products, results in potentially widespread 

exposure across the U.S. and its territories. 

The registration review risk assessment will consider only the use of DSS as an active 

ingredient (in pet shampoos). Its use as an inert ingredient will be considered in the risk 

assessments for those active ingredients with which it is formulated. In any case, the nonpesticidal uses of DSS are expected to dominate both human and wildlife exposure to this 

chemical. 

IV. Receptors 

 1. Aquatic and Terrestrial Effects 

The receptor is the biological entity that is exposed to the stressor (EPA, 1998.) Given its 

widespread use (non-pesticidal), all types of biological receptors (birds, mammals, terrestrial 

plants, freshwater fish, etc.) are expected to be potentially exposed to DSS. 

Consistent with the process described in the Overview Document (EPA, 2004), this risk 

assessment uses a surrogate species approach in its evaluation of DSS. Toxicological data 

generated from surrogate test species, which are intended to be representative of broad 

taxonomic groups, are used to extrapolate to potential effects on a variety of species (receptors) 

included under these taxonomic groupings. 

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Acute and chronic toxicity data from studies submitted by pesticide registrants along with 

the available open literature are used to evaluate the potential direct effects of DSS to the aquatic 

and terrestrial receptors identified in this section. This includes toxicity data on the technical 

grade active ingredient, degradates, and when available, formulated products (e.g. “Six-Pack” 

studies of mammalian toxicity). The open literature studies are identified through EPA’s 

ECOTOX database (http://cfpub.epa.gov/ecotox/), which employs a literature search engine for 

locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of 

both sources of data can also provide insight into the direct and indirect effects of DSS on biotic 

communities from loss of species that are sensitive to the chemical and from changes in structure 

and functional characteristics of the affected communities. 

Table IV.2 provides a summary of the taxonomic groups and the surrogate species tested 

to help understand potential acute ecological effects of pesticides to these non-target taxonomic 

groups. In addition, the table provides a preliminary overview of the potential acute toxicity of 

DSS by providing the acute toxicity classifications. Aside from mammalian toxicity data, the 

data available for DSS are from other EPA programs (OPPT and ORD) or from the open 

scientific literature. 

Table IV.2. Test Species Evaluated for Assessing Potential Ecological Effects of Dioctyl 

Sodium Sulfosuccinate (DSS) and the Associated Acute Toxicity Classification 

Taxonomic Group Example(s) of Surrogate Species Acute Toxicity Classification 

Birds1 Mallard (Anas platyrhynchos) 

Bobwhite (Colinus virginianus) No data 

Mammals Laboratory rat (Rattus norvegicus) Slightly toxic 

Insects Honey bee (Apis mellifera L.) No data 

Freshwater fish2 Bluegill sunfish (Lepomis macrochirus) 

Rainbow trout (Oncorhynchus mykiss) Slightly toxic 

Freshwater invertebrates Water flea (Daphnia magna) Slightly toxic 

Estuarine/marine fish Inland Silversides (Menidia spp.) Slightly toxic 

Estuarine/marine 

invertebrates 

Mysid shrimp (Americamysis bahia)

Copepod (Acartia tonsa) 

Brine shrimp (Artemia spp.) 

Slightly toxic 

Terrestrial plants3 Wandering Jew (Tradescantia bicolor) No toxicity classification 

Aquatic plants and algae available for plants Pseudokirchneriella subcapita 

Anabaena CPB4337 1

 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 2

 Freshwater fish may be surrogates for aquatic-phase amphibians. 3

 Four species of two families of monocots, of which one is corn; six species of at least four dicot families, of which one is 

soybeans. 

No data to describe any potential impacts to the acute (mortality) and chronic assessment 

endpoints (growth and reproduction) were found in the literature for birds, nor was there any data 

for invertebrates, pending the ECOTOX literature search. Data for terrestrial plants is limited to 

one, non-standard species (Tradescantia bicolor). Values for freshwater and estuarine fish, 

invertebrates and algae, as well as earthworms, derived from quantitative structure-activity 

relationships (QSAR) may be used in the risk assessment. 

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 2. Ecosystems Potentially at Risk 

The ecosystems at risk are often extensive in scope, and as a result it may not be possible 

to identify specific ecosystems during the development of a baseline risk assessment. However, 

in general terms, terrestrial ecosystems potentially at risk could include the treated field and 

areas immediately adjacent to the treated field that may receive drift or runoff. Areas adjacent to 

the treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow 

fields or grasslands, woodlands, riparian habitats and other uncultivated areas. 

 Aquatic ecosystems potentially at risk include water bodies adjacent to, or down stream 

from, the treated field and might include impounded bodies such as ponds, lakes and reservoirs, 

or flowing waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also 

includes marine ecosystems, including estuaries. 

 Aquatic exposure may occur as the result of DSS use in pet shampoos. Used wash water 

may be discharged directly to storm drains, or via sanitary sewers to wastewater treatment plants 

(WWTPs), and then discharged to receiving waters. Aquatic exposure is also expected from 

agricultural use as an inert ingredient, as well as the numerous other uses of DSS. 

The Ecological Incident Information System (EIIS) will be searched for any DSS-related 

ecological incidents for use in the DSS risk assessment. 

 

V. Assessment Endpoints 

Assessment endpoints represent the actual environmental value that is to be protected, 

defined by an ecological entity (species, community, or other entity) and its attribute or 

characteristics (EPA, 1998). For DSS, the ecological entities may include the following: birds, 

mammals, freshwater fish and invertebrates, estuarine/marine fish and invertebrates, terrestrial 

plants, insects, and aquatic plants and algae. The attributes for each of these entities may include 

growth, reproduction, and survival. (See Table 3 in Section II.F.2, the Analysis Plan, for further 

discussion.) 

VI. Conceptual Model 

For a pesticide to pose an ecological risk, it must reach ecological receptors in 

biologically significant concentrations. An exposure pathway is the means by which a pesticide 

moves in the environment from a source to an ecological receptor. For an ecological pathway to 

be complete, it must have a source, a release mechanism, an environmental transport medium, a 

point of exposure for ecological receptors, and a feasible route of exposure. 

A conceptual model provides a written description and visual representation of the 

predicted relationships between DSS, potential routes of exposure, and the predicted effects for 

the assessment endpoint. A conceptual model consists of two major components: risk hypothesis 

and a conceptual diagram (EPA, 1998). 
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 1. Risk Hypothesis 

 For DSS, the following ecological risk hypothesis is being employed for this baseline risk 

assessment: 

DSS, when used in accordance with the label, results in potential adverse effects upon the 

survival, growth, and reproduction of non-target terrestrial and aquatic organisms. 

Given the degree of persistence of DSS and its degree of mobility, there is a likelihood of 

exposure to terrestrial and/or aquatic organisms.

 

 2. Conceptual Diagram 

The potential exposure pathways and effects of the pet shampoo uses of DSS as an 

insecticide to non-target terrestrial and aquatic organisms and plants are depicted in Figure 1. 

Solid arrows depict the most likely routes of exposure and effects; dashed lines depict potential 

routes of exposure not considered likely for DSS. As depicted in this figure, transport 

mechanisms (e.g. sources) for shampoo use applied on pets, mammals, and reptiles may result in 

the movement of the pesticide into aquatic (water) and terrestrial (soil) habitats. The movement 

away from the site of application represents exposure pathways for a broad range of biological 

receptors of concern (non-target animals) and the potential attribute changes, i.e., effects such as 

reduced survivals, growth, and reproduction in the receptors. 

Aquatic organism exposure to DSS is expected to occur as a result of the discharge of pet 

shampoo to sewage treatment works, and the subsequent release of treated sewage to receiving 

waters (see Figure 1). 

Terrestrial organism and plant exposure to DSS from its indoor use is likely to be 

negligible. Inhalation exposure is not expected due to the low vapor pressure of DSS. Based on 

its use as a pet shampoo, including mammals and reptiles, direct acute effects to terrestrial 

animals are not anticipated. 

Overall, indoor uses within closed structures, will not likely result in significant exposure to 

aquatic or terrestrial animals and plants; runoff and drift to these species is expected to be very 

low for the indoor uses; while aquatic organisms and plants may be exposed to discharged water 

via the sewerage. 
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VII. Analysis Plan Options 

This is the first review of DSS as an active ingredient. An inert assessment was 

conducted in 2006. No environmental risks of concern were identified at that time. 

 This assessment will be conducted largely on the basis of open literature toxicity data and 

estimated environmental fate properties, due to the lack of registrant submitted data. There were 

few data requirements, based on the limited use pattern (pet shampoo) of the registered active 

ingredient. 

 

1. Measures of Effects and Exposure 

1.1 Measures of Aquatic Exposure

Aquatic wildlife and plants may be exposed to dissolved residues of DSS in water bodies 

that receive used wash water runoff from pet shampoos, and from agricultural use as an inert 

ingredient, as well as numerous other uses. 

Any estimation of exposure to DSS from the pet shampoo uses, distinct from its use as an 

inert ingredient, or distinct from its dominant industrial and human pharmaceutical uses, would 

not be meaningful. Estimates of safe exposure levels to DSS will be calculated from the 
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available toxicity data, and will be used during the risk assessment for those active ingredients 

with which it is formulated. 

1.2. Measures of Terrestrial Exposure 

Exposure from small quantities of shampoo use may be quantified with the Down-theDrain model (http://www.epa.gov/oppt/exposure/index.htm), or by using the solubility of DSS as 

a limiting exposure. 

 1.3. Measures of Effect 

Measures of effect are obtained from a suite of registrant-submitted guideline studies, 

which were conducted with a limited number of surrogate test species. For DSS, the data will be 

supplemented with open literature studies. The test species are not intended to be representative 

of the most sensitive species but rather were selected based on their ability to thrive under 

laboratory conditions. Toxicity testing reported in this risk assessment utilizes surrogate species 

to represent all freshwater fish (2000+) and bird (680+) species in the U.S. When guideline or 

open literature studies are not available, a quantitative structure-activity relationship (QSAR) 

model may be used as a surrogate to estimate the effects. 

The acute measures of effect used in this screening-level assessment are the LD50 (Lethal 

Dose), LC50 (Lethal Concentration) or EC50 (Effects Concentration). These measures of acute 

toxicity result in 50% of the respective effect in tested organisms. The endpoints for chronic 

measures of exposure are the NOAEC (No Observed Adverse Effects Concentration) and the 

NOAEL (No Observed Adverse Effects Level). 

Table V lists the measures of environmental exposure and ecological effects used to 

assess the potential risks of DSS to non-target animals and plants. The methods used to assess 

the risk are consistent with those outlined in the document “Overview of the Ecological Risk 

Assessment Process in the Office of Pesticide Programs” (USEPA, 2004). 

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Table V - Measures of Exposure and Effect Used in Assessing Potential Risks Associated 

with the Proposed Use of Dioctyl Sodium Sulfosuccinate on Pets 

Assessment Endpoint Surrogate Species and Measures of 

Ecological Effect1 Measures of Exposure 

Birds2

Survival 

Bobwhite quail or Mallard duck acute LD50 : 

no data available

Bobwhite quail and Mallard duck acute LC50: 

no data available 

Maximum residues on food 

items (foliar) 

Reproduction 

and Growth 

Bobwhite quail and Mallard duck NOAECs: 

no data available 

Mammals 

Survival 

Laboratory rat LD50: 1800 mg a.i./kg-bw 

(JECFA report 1991

http://www.who.int/ipcs/food/jecfa/en/)

Reproduction 

and Growth 

Laboratory rat NOAEC: 1000 mg a.i./kg-diet 

(JECFA report 1991) 

Freshwater fish3 

Survival Rainbow trout LC50 : 28 mg a.i./L 

(Goodrich 1990) 

Peak EEC

Reproduction 

and Growth QSAR fish NOAEC: 0.261 mg a.i./L* 60-day average EEC 

Freshwater 

invertebrates 

Survival 

Artemia Brine shrimp EC50: 6.2 mg a.i./L 

(Nalco 2005) Peak EEC 

Reproduction 

and Growth 

 QSAR Water flea NOAEC: 0.732 mg 

a.i./L* 21-day average EEC

Estuarine/marine 

fish 

Survival Inland silverside LC50: 39 mg a.i./L 

(Hemmer 2010)

Peak EEC

Reproduction 

and Growth QSAR Fish NOAEC: 1.205 mg a.i./L* 60-day average EEC 

Estuarine/marine 

invertebrates 

Survival 

Mysid LC50: 12.6 mg a.i./L 

(Hemmer 2010) 

Eastern oyster EC50: no data available 

Peak EEC 

Reproduction 

and Growth 

QSAR Mysid NOAEC: 3.051* 

Eastern oyster NOAEC: no data available 21-day average EEC 

Terrestrial plants4 Survival and 

growth 

Monocot seedling emergence EC25 and 

NOAEC: no data available 

Dicot seedling emergence EC25 and NOAEC: 

no data available 

Estimates of drift and runoff 

Monocot vegetative vigor EC to non-target areas 25 not available; 

while NOAEC = <139 mg/L (Wagner 2006) 

Dicot vegetative vigor EC25 and NOAEC: 

 no data available 

Insects Survival (not 

quantitatively 

assessed) 

Honeybee LD50 :no data available Maximum application rate 
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Table V - Measures of Exposure and Effect Used in Assessing Potential Risks Associated 

with the Proposed Use of Dioctyl Sodium Sulfosuccinate on Pets 

Assessment Endpoint Surrogate Species and Measures of 

Ecological Effect1 Measures of Exposure 

Terrestrial 

Invertebrates Survival QSAR Earthworm LD50: 1364 mg ai/kg* Broadleaf plants and small 

insects EEC 

Aquatic plants Survival and 

growth 

Duckweed EC50 and NOAEC: 

no data available 

Algae EC50 = 39.5 mg a.i./L; (Rosal 2010) 

while NOAEC not available

Peak EEC 

1 The most sensitive species tested within taxonomic groups is used for baseline risk assessments. 

2 Birds represent surrogates for amphibians (terrestrial-phase) and reptiles. 

3 Freshwater fish represent surrogates for amphibians (aquatic-phase). 4 Four species of two families of monocots - one is corn, six species of at least four dicot families, of which one is 

soybeans. 

5

 LD50 = Lethal dose to 50% of the test population; NOAEC = No observed adverse effect concentration; LOAEC = 

Lowest observed adverse effect concentration; LC50 = Lethal concentration to 50% of the test population; EC50/EC25

= Effect concentration to 50%/25% of the test population. 

* Estimated by QSAR (Quantitative Structure-Activity Relationship; ECOSAR v1.00) 

 1.4 Integration of Exposure and Effect 

The exposure and toxicity effects data are integrated in order to evaluate the risks of 

adverse ecological effects on non-target species. For the risk assessment of DSS, the risk 

quotient (RQ) method is used to compare estimated exposure and measured toxicity values. The 

RQ method involves dividing estimated environmental concentrations (EEC) by acute and 

chronic toxicity values. The resulting RQs are then compared to the Agency’s Levels of 

Concern (LOC) (USEPA, 2004) (Table V). These criteria are used to indicate when applications 

of DSS, as directed on the label, have the potential to cause adverse effects to non-target animals. 
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Table V - Agency Risk Quotient (RQ) Metrics and Levels of Concern (LOC) Per Risk Class 

RISK CLASS RISK DESCRIPTION RQ LOC 

Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non-listed animals from acute 

exposures 

Peak EEC/LC501

0.5 

Acute 

Restricted Use 

Potential for effects to animals from acute exposures 

Risks may be mitigated through restricted use classification

Peak EEC/LC501

0.1 

Acute Listed 

Species 

Listed species may be potentially affected by acute 

exposures 

Peak EEC/LC501

0.05 

Chronic Potential for effects to non-listed and listed animals from 

chronic exposures 

60-day EEC/NOAEC 

(fish) 1 

21-day EEC/NOAEC 

(invertebrates) 

Aquatic Plants 

Non-Listed Potential for effects to non-listed plants from exposures Peak EEC/EC50 1 

Listed Potential for effects to listed plants from exposures Peak EEC/NOAEC or 

EC052 1 

Terrestrial Animals (mammals and birds) 

Acute Potential for effects to non-listed animals from acute 

exposures 

EEC/LC50 (Dietary) 0.5 

EEC/LD50 (Dose) 

Acute 

Restricted Use 

Potential for effects to animals from acute exposures 

Risks may be mitigated through restricted use classification

EEC/LC50 (Dietary) 0.2 

EEC/LD50 (Dose) 

Acute Listed 

Species 

Listed species may be potentially affected by acute 

exposures 

EEC/LC50 (Dietary) 0.1 

EEC/LD50 (Dose) 

Chronic Potential for effects to non-listed and listed animals from 

chronic exposures EEC/NOAEC 1 

Terrestrial Invertebrates 

Acute Listed 

Species 

Listed species may be potentially affected by acute 

exposures 

EEC/LD50 0.05 

Terrestrial and Semi-Aquatic Plants 

Non-Listed Potential for effects to non-target, non-listed plants from 

exposures 

EEC/ EC25 1 

Listed Plant Potential for effects to non-target, listed plants from 

exposures 

EEC/ NOAEC or 

EC052 1 

1 LC50 or EC50. 2 An EC05 is used when a NOAEC is not available

VIII. Endangered Species Assessment 

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), 

EPA will evaluate risks to Federally-listed threatened and/or endangered (listed) species from 

uses of DSS. This assessment will be conducted in accordance with the Overview Document 

(USEPA 2004), provisions of the ESA, and the Services’ Endangered Species Consultation 

Handbook (USFWS/NMFS 1998). 
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The assessment of effects associated with registrations of DSS is based on an action area. 

The action area is considered the area directly or indirectly affected by the federal action, as 

indicated by the exceedance of Agency Levels of Concern (LOCs) used to evaluate direct or 

indirect effects. The Agency’s approach to defining the action area under the provisions of the 

Overview Document (USEPA 2004) considers the results of the risk assessment process to 

establish boundaries for that action area with the understanding that exposures below the 

Agency’s defined LOCs constitute a no-effect threshold. For the purposes of this assessment, 

attention will be focused on the footprint of the action (i.e., the area where DSS application 

occurs), plus all areas where offsite transport (i.e., runoff, volatilization and long-range 

atmospheric transport, etc.) may result in potential exposure that exceeds the Agency’s LOCs. 

Specific measures of ecological effect that define the action area for listed species include any 

direct and indirect effects and/or potential modification of its critical habitat, including reduction 

in survival, growth, and reproduction as well as the full suite of sublethal effects available in the 

effects literature. Therefore, the action area extends to a point where environmental exposures 

are below any measured lethal or sublethal effect threshold for any biological entity at the whole 

organism, organ, tissue, and cellular level of organization. In situations where it is not possible 

to determine the threshold for an observed effect, the action area is not spatially limited and is 

assumed the entire United States. 

IX. Drinking Water Assessment

The Health Effects Division has completed a Scoping Document (LaMay 2010) for the 

registration review of DSS. HED does not anticipate that there will be any human health effects 

of concern. Therefore, EFED will not conduct a drinking water assessment during registration 

review. 

X. Clean Water Act 

DSS is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act, based on information provided at 

http://oaspub.epa.gov/tmdl/waters_list.impairments?p_impid=3 (accessed 11/17/08).

The Agency invites submission of water quality data for this pesticide. To the extent 

possible, data should conform to the quality standards in Appendix A of the OPP Standard 

Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s 

Registration Review Risk Assessment and Management Process (see: 

http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf) in order to ensure 

they can be used quantitatively or qualitatively in pesticide risk assessments. 

XI. Anticipated Data Needs 

 

Due to the nature of DSS shampoo use on pets, mammals, and reptiles, additional data on 

terrestrial animals (birds, reptiles, terrestrial-phase amphibians) will not be required. In addition, 

because DSS as an active ingredient is registered for indoor uses and according to the updated 

data requirements in 40 CFR part 158 (October 2007), it is anticipated that additional ecological 
16 

data will not be required for indoor uses. QSAR estimates or conservative assumptions may be 

used in the risk assessment, if needed. 

XII. Open Literature 

 The Agency will conduct a search of the open literature to determine if any ecotoxicity 

data relevant to DSS are available. If so, an evaluation will be made as to whether or not the data 

are adequate for use in a risk assessment. The Agency uses the ECOTOX database as its 

mechanism for searching the open literature. ECOTOX integrates three previously independent 

databases - AQUIRE, PHYTOTOX, and TERRETOX - into a system, which includes toxicity 

data derived predominately from the peer-reviewed literature for aquatic life, terrestrial plants, 

and terrestrial wildlife, respectively. 
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XIII. Bibliography 

American Cyanamid Company, 1970. Report on Aerosol OT successive generation studies in 

rats. Report No. 70-239, Dec. 30, 1970. 

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