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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-ethylhe xoxy)-1,4-dioxobutane-2-sulfonate

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repared by: Stephen Carey, Biologist William P. Eckel, Ph.D. Senior Science Advisor U. S. Environmental Protection Agency Office of Pesticide Programs E nvironmental Fate and Effects Division E nvironmental Risk Branch III 1200 Pennsylvania Ave., NW M

ail Code 7507P Washington, DC 20460 R eviewed by: Mark Corbin, Branch Chief

D ate: December 20, 2010 Field Co d3 Table of Contents

I. Purpose of Problem Formulation ...................................................................................... .... 4 II. Nature of Regulatory Action ................................................................................................... 4 A. DSS Regulatory History................................................................................................... 4 5 1. Nature of the Chemical Stressor ..................................................................................... . 5 2. Overview of Pesticide Usage ............................................................................................. 6 IV. Receptors .....................................................................................................................

........ 6 7 1. Aquatic and Terrestrial Effects ........................................................................................ 6 7 2. Ecosystems Potentially at Risk ..................................................................................... 8 9 V. Assessment Endpoints ..........................................................................................................

. 8 9 VI. Conceptual Model ...................................................................................................

......... 8 9 1. Risk Hypothesis ....................................................................................................

...... 9 10 2. Conceptual Diagram .................................................................................................

.. 9 10 VII. Analysis Plan Options .............................................................................................

... 10 11 1. Measures of Effects and Exposure ................................................................................. 10 11 VIII. Endangered Species Assessment .................................................................................. 14 15 IX. Drinking Water Assessment ............................................................................................ 15 16 X. Clean Water Act ...............................................................................................................

. 15 16 XI. Anticipated Data Needs ................................................................................................... 15 16 XII. Open Literature ............................................................................................................... 16 174 

### 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 (D SS). 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 a nd characterizing the risk (EPA, 1998).


### II. Nature of Regulatory Action

Under the Federal Insecticide, Fungicide, a nd Rodenticide Act (FIFRA), all pesticides sold or distributed in the Un ited States generally must be registered by the Environmental Protection Agency (EPA). In determining whether a pesticide can be regist ered in the U.S., EPA evaluates its safety to non-target species base d 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 abili ty to assess risk evolves and as policies and practices change, all registered pesticides co ntinue to meet the st atutory standard of no unreasonable adverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur ov er time. Through the new registration review program, the Agency periodically reevaluates pestic ides 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 Inse cticide, Fungicide, and Rodenticid e Act (FIFRA), the Agency is beginning its evaluation of dioc tyl sodium sulfosuccinate (DSS) to determine whether it continues to meet the FIFRA standard for re gistration. This problem formulation for the environmental fate, ecological ri sk, and endangered species assessm ent chapter in support of the registration review will be poste d 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 ingredie nt, there are no food uses. However, as an inert ingredient there are exemptions from the requirement of a tolera nce 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 th e active ingredient in shampoos and spray pet products, which are registered in combination with undecylenic acid (PC 085501). Diocty l 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.5 Toxicity information for DSS is largely from literature studies; most guideline toxicity studies are not available, and ha ve been previously waived (exc ept acute studies) by the Office of Pesticide Programs (OPP) because of its low toxicity.

DSS has previously been evaluated as an in ert ingredient (June 30, 2006). That review did not identify any ecol ogical 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 aci d, 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-m 3 /mol) 5X10-12 atm-cu m/mole (est.) Solubility in water (g/L) 15,000 mg/L @ 25°C Log K ow 3.95 (est.) pK a /pK b 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 wetti ng agent and food additive may re sult in its release to the environment through various waste streams. If rel eased to soil, the expected mobility of DSS is low to very high. If released to water, DSS will be essentially nonvolatil e. 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 ac tivated sewage sludge in dicates 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 ra dicals with an estimated half-life of 18 hours. Physical6 removal from air can occur through wet and dr y 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 ingr edient (anionic surfact ant) in pet shampoos, and as an inert ingredient in food-use pr oducts, in which it is exempt from th e requirement of a tolerance. DSS has a human pharmaceutical use as a stool soften er 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 agen t in industrial, pharmaceutical, cosmetic, and food applications, as a dispersing an d solubilizing agent in foods, and as an adjuvant in tablet formation (Merck Index, 1983).

DSS is also used in oil-spill dispersing ag ents, such as Corexit 9500A (Nalco Energy Services, L.P.).

The use of DSS in food-use agricultural pe sticide formulations, and as a pet shampoo, as well as its numerous industri al and consumer products, resu lts 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 in ert ingredient will be co nsidered in the risk assessments for those active ingredients with which it is formulated. In any case, the nonpesticidal uses of DSS are expected to domi nate 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 stresso r (EPA, 1998.) Given its widespread use (non-pesticidal), all types of biological recepto rs (birds, mammals, terrestrial plants, freshwater fish, etc.) are expect ed to be potentially exposed to DSS.

Consistent with the process described in th e 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 poten tial effects on a variety of species (receptors) included under these ta xonomic groupings. Field Co d7 Acute and chronic toxicity da ta from studies submitted by pesticide registrants along with the available open literature are us ed to evaluate the potential dire ct effects of DSS to the aquatic and terrestrial receptors identifi ed in this section. This include s toxicity data on the technical grade active ingredient, degradates, and when available, formulated products (e.g. “Six-Pack” studies of mammalian toxicity). The open li terature studies are identified through EPA’s ECOTOX database (http://cfpub.epa.gov/ecotox/ ), which employs a literature search engine for locating chemical toxicity data fo r aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also prov ide insight into the direct and i ndirect 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 pesticid es to these non- target taxonomic groups. In addition, the table provides a prelimin ary overview of the poten tial acute toxicity of DSS by providing the acute toxicity classificatio ns. 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 Assess ing Potential Ecologica l Effects of Dioctyl Sodium Sulfosuccinate (DSS) and the Associ ated Acute Toxicity Classification Taxonomic Group Example(s) of Surrogate Species Acute Toxicity Classification

Birds 1 Mallard ( Anas platyrhynchos ) Bobwhite ( Colinus virginianus ) No data
Mammals Laboratory rat ( Rattus norvegicus ) Slightly toxic Insects Honey bee ( Apis mellifera L. ) No data

Freshwater fish 2 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 plants 3 Wandering Jew ( Tradescantia bicolor ) No toxicity classification available for plants Aquatic plants and algae Pseudokirchneriella subcapita Anabaena CPB4337

1 Birds represent surrogates for terrest rial-phase amphibians and reptiles.
2 Freshwater fish may be surroga tes 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 reproduc tion) were found in the literature for birds, nor was there any data for invertebrates, pending the ECOTOX literature sear ch. Data for terrestrial plants is limited to one, non-standard species ( Tradescantia bicolor ). Values for freshwater and estuarine fish, invertebrates and algae, as we ll as earthworms, derived from quantitative structure-activity relationships (QSAR) may be us ed in the risk assessment. Field Co d

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Field Co d8 2. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in sc ope, and as a result it may not be possible to identify specific ecosystems during the developmen t of a baseline risk assessment. However, in general terms, terrestrial ecosystems potentiall y 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 un cultivated areas.

Aquatic ecosystems potentially at risk include water bodies adjacent to, or down stream from, the treated field and might include impounde d 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 vi a sanitary sewers to wastewater treatment plants (WWTPs), and then discharged to receiving wate rs. 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 enviro nmental value that is to be protected, defined by an ecological entity (species, comm unity, or other entity) and its attribute or characteristics (EPA, 1998). For DSS, the ecologi cal entities may include the following: birds, mammals, freshwater fish and invertebrates, estuar ine/marine fish and invertebrates, terrestrial plants, insects, and aquatic plants and algae. Th e 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 c oncentrations. An exposure pathway is the means by which a pesticide moves in the environment from a source to an eco logical 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 receptor s, and a feasible route of exposure.

A conceptual model provides a written desc ription and visual re presentation of the predicted relationships between D SS, potential routes of exposure, and the predicted effects for the assessment endpoint. A conceptual model cons ists of two major comp onents: risk hypothesis and a conceptual diagram (EPA, 1998).9 1. Risk Hypothesis

For DSS, the following ecological risk hypothesi s 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-targ et terrestrial and aquatic organisms. Given the degree of persistence of DSS and its degree of mobility, th ere 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 terr estrial and aquatic organisms and plants are depicted in Figure 1

. Solid arrows depict the most likely routes of e xposure and effects; dashed lines depict potential routes of exposure not consider ed likely for DSS. As depict ed in this figure, transport mechanisms ( e.g . sources) for shampoo use applied on pe ts, mammals, and reptiles may result in the movement of the pesticide into aquatic (wate r) and terrestrial (soil) habitats. The movement away from the site of application represents e xposure pathways for a br oad 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 subse quent release of treate d 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 re ptiles, direct acute e ffects to terrestrial animals are not anticipated.

Overall, indoor uses within clos ed 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 a nd plants may be exposed to discharged water via the sewerage.10 

### VII. Analysis Plan Options

This is the first review of DSS as an ac tive 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 literatu re 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 sh ampoos, 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 exposur e levels to DSS will be calculated from the11 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 us e 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 surr ogate 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 se lected based on their ability to thrive under laboratory conditions. Toxicity te sting 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 surroga te to estimate the effects.

The acute measures of effect used in th is screening-level assessment are the LD 50 (Lethal Dose), LC 50 (Lethal Concentration) or EC 50 (Effects Concentration). These measures of acute toxicity result in 50% of the re spective effect in tested organi sms. The endpoints for chronic measures of exposure are the NOAEC (No Observ ed Adverse Effects Concentration) and the NOAEL (No Observed Advers e Effects Level).

Table V lists the measures of environmental ex posure 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). Field Co d

Field Co d12 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 Effect 1 Measures of Exposure

Birds 2 Survival Bobwhite quail or Mallard duck acute LD 50 : no data available Bobwhite quail and Mallard duck acute LC 50 : 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 LD 50 : 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 fish 3 Survival Rainbow trout LC 50 : 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 EC 50 : 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 LC 50 : 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 LC 50 : 12.6 mg a.i./L (Hemmer 2010) Eastern oyster EC 50 : no data available Peak EEC

Reproduction and Growth QSAR Mysid NOAEC: 3.051* Eastern oyster NOAEC: no data available 21-day average EEC

Terrestrial plants 4 Survival and growth Monocot seedling emergence EC 25 and NOAEC: no data available Dicot seedling emergence EC 25 and NOAEC: no data available Estimates of drift and runoff to non-target areas Monocot vegetative vigor EC 25 not available; while NOAEC = <139 mg/L (Wagner 2006)

Dicot vegetative vigor EC 25 and NOAEC:
no data available

Insects Survival (not quantitatively

assessed) Honeybee LD 50 :no data available Maximum application rate13 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 Effect 1 Measures of Exposure

Terrestrial Invertebrates Survival QSAR Earthworm LD 50 : 1364 mg ai/kg* Broadleaf plants and small insects EEC

Aquatic plants Survival and growth Duckweed EC 50 and NOAEC: no data available

Algae EC 50 = 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 surroga tes for amphibians (aquatic-phase).
4 Four species of two families of monocots - one is corn, six species of at least four dico t families, of which one is soybeans.
5 LD 50 = Lethal dose to 50% of the test population; NOAEC = No observed adverse effect concentration; LOAEC = Lowest observed adverse effect concentration; LC 50 = Lethal concentration to 50% of the test population; EC 50 /EC 25 = Effect concentration to 50%/25% of the test population. * Estimated by QSAR (Quantitative Structur e-Activity Relationship; ECOSAR v1.00)
1.4 Integration of Exposure and Effect

The exposure and toxicity effects data are inte grated in order to ev aluate the risks of adverse ecological effects on non-ta rget species. For the risk assessment of DSS, the risk quotient (RQ) method is used to compare estimate d exposure and measured toxicity values. The RQ method involves dividing es timated 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.14 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/LC 50 1 0.5

Acute Restricted Use Potential for effects to an imals from acute exposures Risks may be mitigated through restricted use classification Peak EEC/LC 50 1 0.1

Acute Listed Species Listed species may be potentially affected by acute
exposures Peak EEC/LC 50 1 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/EC 50 1 Listed Potential for effects to listed plants from exposures Peak EEC/NOAEC or EC 05 2 1

Terrestrial Animals (mammals and birds)
Acute Potential for effects to non-listed animals from acute
exposures EEC/LC 50 (Dietary) 0.5 EEC/LD 50 (Dose)

Acute Restricted Use Potential for effects to an imals from acute exposures Risks may be mitigated through restricted use classification EEC/LC 50 (Dietary) 0.2 EEC/LD 50 (Dose)
Acute Listed Species Listed species may be potentially affected by acute
exposures EEC/LC 50 (Dietary) 0.1 EEC/LD 50 (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/LD 50 0.05

Terrestrial and Semi-Aquatic Plants Non-Listed Potential for effects to non-target, non-listed plants from
exposures EEC/ EC 25 1

Listed Plant Potential for effects to non-target, listed plants from
exposures EEC/ NOAEC or EC 05 2 1

1 LC 50 or EC 50 . 2 An EC 05 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 threat ened and/or endangered (listed) species from uses of DSS. This assessment will be conduc ted in accordance with the Overview Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered Species Consultation Handbook (USFWS/NMFS 1998)

.15 The assessment of effects associated with regi strations 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 understandi ng that exposures below the Agency’s defined LOCs constitute a no-effect threshold. For th e 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 potent ial exposure that exceeds the Agency’s LOCs. Specific measures of ecological effect that defi ne the action area for listed species include any direct and indirect effects and/or potential modification of its cri tical habitat, including reduction in survival, growth, and reproductio n as well as the full suite of s ublethal effects available in the effects literature. Therefore, the action area ex tends 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 cellula r level of organization. In situ ations 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 complete d a Scoping Document (LaMay 2010) for the registration review of DSS. HED does not anticipate that there wi ll be any human health effects of concern. Therefore, EFED will not conduct a drinking water assessm ent during registration review.



### X. Clean Water Act

DSS is not identified as a cause of impairmen t 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 Wa ter Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management Process (see: http://www.epa.gov/oppfead1/cb/p pdc/2006/november06/session1-sop.pdf ) in order to ensure they can be used quantitatively or qual itatively 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, reptile s, terrestrial-phase amphibians) will not be required. In addition, because DSS as an active ingredient is register ed for indoor uses and according to the updated data requirements in 40 CFR part 158 (October 2007) , it is anticipated that additional ecological16 data will not be required for i ndoor 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. EC OTOX 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.17 

### XIII. Bibliography

American Cyanamid Company, 1970. Report on Ae rosol OT successive generation studies in rats. Report No. 70-239, Dec. 30, 1970.

Carlsson, C., et al. Are pharmaceuticals pote nt environmental pollutants? Part II: Environmental risk assessments of selected pharmaceutical excipients. Science of the Total Environment 364 (2006) 88-95.

Goodrich, M. et al. The Toxicity, bioaccumu lation, metabolism and elimination of dioctyl sodium sulfosuccinate DSS in rainbow trout (Oncorhynchus mykiss). Wat. Res. Vol. 25, no. 2, pp. 119-124, 1991.

Hazleton Laboratories America, Inc. 1986. Excerpt from the final report of the three generation reproduction study with dioctyl sodium sulf osuccinate in rats. Study no. 6123-122, june 27, 1986.

Hemmer, J. et al., National H ealth and Environmental Effect s Research Laboratory, ORD, USEPA, June 30, 2010. Comparative Toxicity of Eight Oil Dispersant products on Two Gulf of Mexico Aquati c Test Species. 11 pp.

LaMay, A. et al. Risk Assessment Branch VII, Health Effects Division, USEPA. Aug. 18, 2010. Memo to Yan Donovan. Subject: Dioctyl Sodium Sulfosuccinate. Human Health Assessment Scoping Document in Support of Registration Review. DP barcode 379581. 7 pp.

Lin, F.S.D., U.S. Food and Drug Administration. Dioctyl Sodium Sulfosuccinate (DSS) WHO Food Additives Series 28. 11 pp.

MacKenzie, K., Henwood, S., Foster, G., Akin, F. , Davis, R., Debaecke, P. et al., 1990. Three generation reproduction study with dioctyl sodium sulfosuccinate in rats. Fundam. Appl. Toxicol. 1591): 53-62.

Nalco Energy Services, L.P. June 14, 2005. Ma terial Safety Data Sheet, Corexit 9500. 10 pp.

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