Docket Number: EPA-HQ-OPP-2009-0301 www.regulations.gov



## Esfenvalerate Final Work Plan Registration Review

June 201023 ESFENVALERATE FINAL WORK PLAN

Introduction :

This is the Environmental Protection Agency’s (EPA’s) Final Work Plan for the registration review of esfenvale rate. This work plan incl udes the expected registration review timeline. The work plan also addre sses public comments received concerning the Preliminary Work Plan in the Summary Document , which was posted in the esfenvalerate registration review dock et (EPA-HQ-OPP-2009-0301), and any other comments concerning the ini tial docket postings. The Summary Document provided information on what EPA knows about the pest icide and what additional risk analyses and data or information the Agency believes are needed to make a registration review

decision.

The Agency is implementing the registration re view program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rode nticide Act (FIFRA), and will review each registered pesticide every 15 years to determ ine whether it continues to meet the FIFRA standard for registration. Ch anges in science, public polic y, and pesticide use practices will occur over time. The registration review program is intended to make sure that, as the ability to assess risk e volves and as policies and pract ices change, all registered pesticides continue to meet the statutory standard. Th e public phase of registration review begins when the initial docket is opened for each case. Information on this program is provided at: http://www.epa.gov/oppsrr d1/registration_review/

.

Esfenvalerate (Case 7406) is a broad spectrum pyrethroid insecticide registered for use on a variety of agricultura l crops and on residential and i ndustrial use sites (both indoor and outdoor). Since esfenvalerate was registered after 1984, it was not subject to the reregistration requirements of FIFRA. Esfenvalerate is the S, S-isomer of fenvalerate, and for the human health risk assessment, es fenvalerate and fenvalerate are considered toxicologically equivalent. A ll fenvalerate registrations were voluntarily cancelled by the registrants in 2008 (73 FR 132).

Comments Received on Preliminary Work Plan :

Multiple comments were received during the 60-day public comment period on the Preliminary Work Plan

. These comments are summarized in this document and changes to the work plan set out in the Preliminary Work Plan are explained. In the Preliminary

Work Plan , EPA also solicited comments on three specific topics: environmental justice, water body impairment, and trade irritants. No comments or information were received during the comment period c oncerning these issues.

Anticipated Risk Assessment and Data Needs:

The Agency will conduct a comprehensive ecol ogical risk assessment for esfenvalerate, including an endangered species risk assessmen t, and update and revise the human health risk assessment. Below is a summary of the i ssues relevant to the registration review of4 esfenvalerate.

Ecological Risk:

• The most recent ecological assessment for esfenvalerate was an endangered species assessment evaluating the potent ial effects of esfenvalerate on the Federally-listed threatened California red-legged frog ( Rana aurora draytonii ) consistent with court orders and settlements, Center for Biological Diversity v. Johnson, et al., No. 02-1580 (N.D. Cal., October 20, 2006). The Agency concluded in February 2008 that esfenvalera te is Likely to Adversely Affect the California red-legged frog and initiated fo rmal consultation with the US Fish and

Wildlife Service under section 7 of the Endangered Species Act.

• The Agency has not conducted a risk assessment that supports a complete endangered species determination. The eco logical risk assessment planned during registration review will allow the Agency to determine whether esfenvalerate’s use has “no effect” or “may affect” fede rally listed threatened or endangered species (listed species) or their designated critical habitats. When an assessment concludes that a pesticide’s use “may aff ect” a listed species or its designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service

and/or National Marine Fi sheries Services (the Services), as appropriate.

• The Agency will require the following additional data in order to conduct a complete ecological risk assessment, including an endangered species assessment,

for all uses:

Environmental Fate

o Guideline number (GLN) 835.4300 - Aerobic Aquatic Metabolism (TGAI)

o GLN 835.4400 - Anaerobic Aquatic Metabolism (TGAI)

Terrestrial Organisms

o GLN 850.2100 - Avian acute oral toxicity for a passerine species [conducted with technical grad e active ingredient (TGAI)]

o GLN 850.2300 - Avian reproduction fo r an upland game bird and waterfowl (TGAI)

o GLN 850.4100 - Terrestrial plants seed ling emergence, Tier II [conducted with a typical end-use product (TEP)] 1

o GLN 850.4150 - Vegetative vigor, Tier II (TEP)

1 Registrants may opt to conduct Tier I terrestrial plant studies, with the understanding that any adverse effects (even if <25%) may necessitate Ti er II studies. Tier II studies will enable the Agency to conduct an endangered species assessment for nontarget plants.5 Aquatic Organisms

o GLN 850.1075 - Acute toxicity to freshwater fish for one cold water and one warm water species (TGAI)

o GLN 850.1075 - Acute toxicity to estuar ine/marine fish for one species (TGAI and TEP)

o GLN 850.1010 - Acute toxicity to freshwater invertebrate (TEP)

o GLN 850.1025 - Acute toxicity to estuar ine/marine invertebrate for the

mollusk and another inverteb rate species (TGAI and TEP)

o GLN 850.1350- Estuarine/marine invert ebrate lifecycle for one species (TGAI)

o GLN 850.1500 - Estuarine/marine fish full life cycle for one species (TGAI)

o GLN 850.1400 - Estuarine/marine earl y life cycle for one species; data from the full lifecycle study may be us ed to fulfill this guideline (TGAI)

o Non-GLN - Whole sediment survival, growth, and reproduction tests with

Chironomus tentans

, Leptocheirus plumulosus , and Hyalella azteca (TGAI)

o GLN 850.4400 – Aquatic plant growth st udies for algae, Tier II (TGAI) 2

o GLN 850.5400 - Aquatic plant growth studi es for vascular plants, Tier II (TGAI)

Exposure

o Non-GLN – Publically owned treatm ent works (POTW) treatability study (bench scale wastewater treatment study) (TGAI)

 The Agency will require a bench sc ale study of wastewater treatment, to assess the percentage of esfenva lerate removed in the biosolids by the treatment, the amount that woul d degrade, and the amount that

would remain in the wastewater. These data would be used to inform removal percentages by wastewater tr eatment, which is an input to the Exposure and Fate Assessment Screening Tool (E-FAST) used by the Agency to assess “down-the-drain” exposure.

• Please refer to the Revised Registration Review: Revised Preliminary Problem Formulation for Ecological Risk, En vironmental Fate, Endangered Species, and Drinking Water Assessment for Esfenvalerate , completed June 21, 2010, located in the docket, for a detailed discussion of the anticipated risk assessment needs.

Human Health Risk:

• The most recent comprehensive human health assessment was completed on July

2 Registrants may opt to conduct Tier I aquatic studies, with the understanding that any adverse effects (even if <25%) may necessitate Tier II studi es. Tier II studies will enable the Agency to conduct an endangered species assess ment for nontarget plants.6 2, 2004 for the new uses of esfenvalerate in /on Brussels sprouts; pistachios; postharvest uses in/on almonds, cocoa beans, peanut kernels and walnuts; canola; head lettuce; cardoon; Chinese cabb age (bok choy); and sweet potato.

• The esfenvalerate risk assessment in 2004 determined that the residue chemistry database was complete except for crop field trial data for the following raw agricultural commodities (RACs): corn, soybean, and sorghum aspirated grain fractions, cotton gin byproducts , pea (field) vines and hay. These data have not been submitted; therefore, the Agency will include them in the registration review Data Call-In (DCI).

• During registration review, the Agency will reassess the esfenvalerate dietary burden to livestock in light of a 2008 update to livestock feedstuff. The Agency updated the livestock feedstuff tables to be more consistent with the modern diet fed to livestock, and in an effort to harmonize the Agency’s approach for assessing dietary burden to livestock with that of other regulatory partners. The 2008 update resulted in a significant reducti on in the percent of several feedstuffs in cattle diet, thus likely re sulting in a lower dietary burden to ruminants. The anticipated reassessment may also indicat e a need to lower livestock commodity

tolerances for esfenvalerate.

• The tolerance expression in 40 CFR 180.379 will be reviewed during registration review to ensure that it appropriately covers the metabolites and degradates of esfenvalerate and that it specifies th e residues to be measured for each commodity.

• The Agency expects that a new drinki ng water exposure assessment (DWA) will be needed in order to incorporate the latest modeling methods for surface water sources of drinking water. Because esfenva lerate is not likely to leach through the soil to reach ground water sources due to it s high sorption potential, ground water exposure will not be included in the DWA.

• During registration review, the Agency w ill update the refined, probabilistic acute and chronic dietary (food and drin king water) exposure assessment for esfenvalerate to include updated drin king water estimated environmental concentrations (EECs), any changes to toxi cological endpoints and safety factors, and updates to the percent crop treated va lues and anticipated residue levels.

• To address potential indoor resident ial post-application risks of concern, esfenvalerate registrants recently submitte d an exposure study for floor residues following crack-and-crevice or broadcas t applications (MRID 47690501). This study was reviewed by the Agency and found to be adequate. These floor deposition data will be considered in a dvance of the complete human health risk assessment planned for registration revi ew, along with a recently submitted residential probabilistic risk assessment: Esfenvalerate Non-Dietary (Residential) Risk Assessment - Development of a Random Walk Approach to Estimate7 Potential Child Incidental Ingesti on (Hand-to-Mouth Contact) Exposures Following Indoor Crack & Crevice Tr eatment (MRID 47772701). The more refined probabilistic assessment may result in lower residential risks than the screening-level deterministic methodol ogy employed in the 2004 human health

risk assessment.

• During registration review, the Agency will conduct a full reassessment of occupational, residential, and aggregate risk, taking into account any relevant changes to toxicological endpoints, safety factors, exposure values, and applicable occupational and residential standa rd operating procedures (SOPs).

• The Agency will require the following data in order to conduct a complete human

health assessment:

o GLN 870.7800 - Immunotoxicity

o GLN 870.3465 - 90-Day Inhalation Toxicity

o GLN 870.6300 - Developmenta l Neurotoxicity (DNT)

o GLN 860.1500 - Crop Field Trials (cor n, soybean, and sorghum aspirated grain fractions, cotton gin byproducts , pea (field) vines and hay)

• While the inhalation guideline calls for a 90-day study, a 28-day study will satisfy the Agency’s intermediate-term inhalation exposure data needs for this chemical based on current use patterns. This modi fication will be noted in the registration

review DCI for esfenvalerate.

• Based on the Agency’s review of existi ng pyrethroid data, EPA has come to the conclusion that the DNT is not a particularly sensitive study for comparing the sensitivity of young and adult animals to pyrethroids. EPA has recently determined that, as an alternative to the generation and submission of a new DNT study, pyrethroid registrants may instead c hoose to cite to th e six previously submitted DNT studies for pyrethroid pesticides. The Agency is also investigating the need for additional e xperimentation, specific to the mode of action and pharmacokinetic characteristics of pyrethroids, to eval uate the potential for increased susceptibility of young or ganisms. A meeting of the FIFRA Scientific Advisory Panel (SAP) is pla nned for July 2010. For more information on the pyrethroid developmental neur otoxicity (DNT) requirement, see http://www.epa.gov/oppsrrd1/reevalua tion/pyrethroids-pyrethrins.html

.

• The Agency will make a decision regarding the need for an FQPA or other database uncertainty/safety factors follo wing receipt of the remaining required toxicity data, and following a final determ ination of the potential for increased susceptibility of infants and children to pyrethroid pesticides based on the results

of all available data.

• Esfenvalerate is a member of the pyret hroid class of insecticides. EPA has developed a draft science policy docum ent on the proposed common mechanism8 of toxicity for naturally-occurring pyreth rins and synthetic pyrethroids, which was supported by the FIFRA SAP. Upon fi nalization of this science policy, the pyrethroids will be subject to a cumula tive risk assessment under the FQPA.

• Please refer to the Human Health Scoping Document in Support of Registration Review for Esfenvalerate, completed December 1, 2009, located in the docket, for

a detailed discussion of the anticipated risk assessment needs for human health.

Other Data Needs:

• GLDN 830.7050 - UV/Visible Light Absorptio n. This study is a new data requirement under 40 CFR part 158 (Produc t Chemistry Data Requirements) for registration of a pesticid e (food and non-food uses). The Agency anticipates requiring this study to obtain basi c information a bout the compound’s identity/composition and the wavelengths at which the compound may be susceptible to photochemical degradation.

Endocrine Disruptor Screening Program

As required under FFDCA section 408(p), EP A has developed the Endocrine Disruptor Screening Program (EDSP) to determine whet her certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two-tiered approach to making the statutorily required determinations. Tier 1 cons ists of a battery of 11 screening assays to identify the potential of a chemical substan ce to interact with th e estrogen, androgen, and or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to inte ract with E, A, or T hormonal systems will proceed to the next stage of the EDSP wher e EPA will determine which, if any, of the Tier 2 tests are necessary based on the availa ble data. Tier 2 te sting is designed to identify any adverse endocrine related eff ects caused by the substance, and establish a quantitative relationship between the dose and the E, A, or T effect.

Between October 2009 and February 2010, EPA issu ed test orders/data call-ins for the first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. This list of chemicals was selected based on the potential for human exposure through pathways such as food and wa ter, residential activity, and certain postapplication agricultural s cenarios. This list should not be construed as a list of known or likely endocrine disruptors.

Esfenvalerate is among the group of 58 pesticide active ingredients on th e initial list to be

screened under the EDSP. For information on the status of the or ders issued under the EDSP for each chemical, please visit our webs ite at http://www.epa.gov/endo/ and click

on the "Status of EDSP Orders/DCIs" in the Highlights Box. Additional information on the EDSP, including the policies and procedures , the list of 67 chemicals, the test guidelines and the Tier 1 sc reening battery, can also be found at this website.9 Timeline :

EPA has created the following estimated ti meline for completion of the registration

review for esfenvalerate.

Registration Review for Esfenvalerate – Projected Registration Review Timeline

Activities Estimated Date
Opening the Docket Open Docket and Public Comment Period December 2009 Close Public Comment February 2010
Case Development
Issue Final Work Plan (FWP) June 2010 Issue Data Call-in (DCI) January – March 2011

Data Submission 1 January – March 2015 Open Public Comment Period for Preliminary Risk Assessments July – September 2016

Close Public Comment Period October - December 2016

Registration Review Decision Open Public Comment Period for Proposed Registration

Review Decision January – March 2017

Close Public Comment Period April - June 2017 Final Registration Review Decision & Begin PostDecision Follow-up 2017

Total (years) 2 8

1. If the registrants choose to cite the six previously submitted DNT studies for pyrethroid pesticides, as explained above, rather than conduct a DNT st udy with esfenvalerate, this time estimate will likely be shortened by approximately two years.

2. An assessment of the potential cumulative risk from the pyrethroid class of insecticides may impact this time estimate.

Summary of Comments and Agency Responses :

The esfenvalerate registration review doc ket was open for a 60-day comment period beginning on December 16, 2009. During the co mment period, multiple comments were received, which are summarized below. Comm ents that prompted a change in the work plan, or are not addressed by other respons e documents included in the esfenvalerate docket, have responses included below. While some comments did f acilitate changes to the work plan, they did not affect the timeline set out in the Preliminary Work Plan

. After consideration of comments received on the Registration Review: Preliminary Problem Formulation for Ecological Risk, Environmental Fate, Endangered Species, and Drinking Water Assessment for Esfenvalerate , the Agency revised this document and the updated version is available in the esfenvalerate regist ration review docket (Docket Number: EPA-HQ-OPP-2009-0301) at www. regulations.gov. The substantive comments received on the ecological Problem Formulation and the human health10 Scoping Document, the Agency’s response, and the revisions to the ecological Problem

Formulation are described below. This doc ument makes final the work plan for the esfenvalerate registration review process.

Comments from DuPont Crop Protection

Ecological Risk Assessment

Comment: Esfenvalerate is registered for use on more than 50 crops. Given the number of crops and the absence of adverse effect s on plants found during extensive residue and performance testing, the potential for esfe nvalerate to reduce survival, reproduction, and/or growth of plants is ne gligible based on usage history and an absence of incidents.

Response: The absence of reported incidents does not rule out the potential for esfenvalerate to reduce survival, reproduction, an d/or growth of plants. No terrestrial plant toxicity data have been submitted for esfe nvalerate. Tier I plant tests are required according to CFR 40 Part 158 for all outdoor uses. The registrant should be aware that if greater than a 25% effect rate is seen at the maximum annua l application rate, a Tier II test may be required. The registrant may c hoose to perform only the Tier II. Whether a Tier I or Tier II study is submitted, it is only after this data has been received and evaluated by the Agency that any new determin ation can be made rela ting to the potential for esfenvalerate to reduce survival, re production, and/or growth of plants.

Comment: The fish full life cycle study should not be required to asse ss the potential for chronic effects on fish. The fish early life stage study should be acceptable. The rationale for the fish full life cycle study give n in Table7-3 neglects a consideration of the differences between fish and daphnia and th e significance of the reproductive effects observed in the daphnia chronic study. The acu te endpoints for fish are much higher than those for daphnia, and fish would not be expe cted to respond similarly to daphnia during chronic exposures. The reproductive effects observed in the daphnia chronic test were observed only at concentrations where ther e were also effects on survival. For the purposes of ecological risk assessments, the endpoints for survival will be sufficiently protective. Chronic exposure of fish in the water column is also unlikely. The sorption

of esfenvalerate to sediment reduces the c oncentration in the wate r phase to extremely low levels so that long term exposures at significant concentr ations is unlikely.

Response: The request for a fish full life cycl e study is not based upon the water flea chronic study alone but upon the weight of evidence that reproductive impacts are potentially being missed in the fish early life stage test. This includes not only the reproductive effects seen in the water flea chroni c test, but also the f act that the estimated environmental concentration (EEC) is greater than 10 percent of the no-observed adverse effect level (NOAEC) in the fi sh early life stage test (40 CFR part 158), which has been identified as characteristic for reprod uctive concerns. Reproduction physiology was affected in the water flea which suggests th at reproduction physiology may be affected in fish. Though reproductive effects were only obs erved at concentrations where effects on survival were seen, similar effects may not necessarily be seen relative to survival between the water flea and fish. Additionally, thinner egg shells are noted in the avian11 reproduction study which could infer problems with embryogenesis. A fish early life stage test does not capture fecundity endpoints that are cap tured by a fish full life cycle test. The outcomes of full life cycle tests on freshwater and estuarine/marine fish, after being evaluated by the Agency, will address these uncertainties.

Human Health Risk Assessment

Comment: The fenvalerate tolerances in 40 CFR 180.379 have been converted to

esfenvalerate tolerances in 40 CFR 180.533 (74 FR Notice 46689-46699, September 11, 2009). During this process, the fenvaler ate tolerance for cabbage (10.0 ppm) was converted to an esfenvalerate tolerance for “cabbage, except Chinese cabbage (3.0 ppm).”

The current Section 3 label for the esfenvale rate end-use product, DuPont Asana XL Insecticide, has a registered use for “Chinese cabbage (tight headed varieties only, e.g. Napa cabbage)”. Therefore, DuPont request s that a correction be made to list an esfenvalerate tolerance of 3.0 ppm for “cabbage, Chinese, napa”.

Response: According to 40 CFR 180.1(g), tolera nces established for pesticides on cabbage also applies to Chinese cabbage (ti ght-headed varieties only). Because napa cabbage is considered a tight -headed variety, the cabbage to lerance should cover this commodity. The Agency agrees that the ex isting esfenvalerate tolerance for “cabbage, except Chinese cabbage” should be changed to “ cabbage”, since napa cabbage is part of the cabbage commodity definition. The Agency anticipates making this change in 2010

and it will not affect the Work Plan.

Comments by California Regional Water Quality Control Board/San Francisco Bay Region, County Sanitation Districts of Lo s Angeles County and Tri-TAC/East Bay Municipal Utility District.

The following individuals submitted comments for the organizations listed above. Writing on behalf of the California Regional Water Quality Control Board/San Francisco Bay Region was Janet B. O’Hara, Water Reso urce Control Engineer/Manager, Pesticide TMDSs. Writing on behalf of the County Sanitation Districts of Los Angeles County was Paul Martyn, Head, Industrial Waste. Writing on behalf of Tri-TAC/East Bay Municipal Utility District was Ben Horenstein, Tri-TAC chair.

The submitters showed strong support for th e planned use of the Agency-wide ECOTOX database and other sources of available, reliabl e data, rather than limiting the data used in the assessment to registrant-submitted data. Additionally, the submitters indicated their support of the requests for environmental fate an d aquatic toxicity data as listed in the Preliminary Work Plan.

Comment : Inclusion of Impacts on Urban Water Quality from Urban Runoff and SewerDischargeThe submitters would like for the Work Plan to reflect impacts on urban water quality from urban runoff and sewer discharge. Speci fically mentioned was the planned inclusion12 of these exposure pathways in a problem formulation for cyphenothrin, another pyrethroid.

Response: The above mentioned exposure pathways will be included in a revised problem formulation for esfenvalerate. Re levant public comments received regarding other pyrethroid problem formulations and consideration of these exposure pathways will

be taken into account.

Comment: Identification and Inclusion of Indoor Us es as a Potential Route of Aquatic Exposure from Pesticide Discharge into Se wers and Subsequent Discharge into the

Environment in Biosolids and Effluent from Publicly Owned Treatment Works (POTW)-

The submitters stated that the Work Plan doe s not identify indoor uses as a possible route of aquatic exposure. Use of esfenvalerate indoors ( e.g ., in households, storage areas, or processing plants) can result in indoor discharges into sewer systems when treated

surfaces are washed with water which is di sposed of down the drain. Contaminated disposal water may be from treated surfaces wa shed with water; carpet cleaning water; or rinse water from mops, rags or brushes us ed to clean treated surfaces. Pesticides discharged in water via this route (as well as from uses on animals) may enter POTWs, and subsequently be discharged into the envir onment in effluent and/or biosolids from the

POTWs. Submitters stated that EPA s hould evaluate potential impacts from

esfenvalerate in both POTW effluents and bioso lids (applied to land) as part of the downthe-drain assessment. Submitters cited a study which found that pyrethroids are not degraded during wastewater treatment and are present in final POTW effluent.

Response : The Agency agrees that indoor uses can result in discharges of esfenvalerate residues into sewer systems and should be in cluded in the assessment as a possible route of exposure to the environment. Assumpti ons will be used to quantify the potential loading to drainage systems. Discharge of esfenvalerate into the environment via POTW effluent will be considered to the best degr ee possible in the assessment. However, EPA does not anticipate assessing potential ecologi cal exposure resulting from application of biosolids to land in registra tion review, as the Agency does not have a methodology to assess this potential route of exposure. Th e EPA Office of Pesticide Programs (OPP) is currently working with other EPA Offices to explore methodology to make quantitative estimates. EPA recognizes the potential e xposure from down-the-drain sources of pyrethroids, and will continue to investigat e ways of more accurately quantifying these sources in fate and ecological exposure assessments. With regard to assessing exposure due to POTW effluent discharge, se e the response to the next comment.

Comment: Development of Revised Methodolog y for Down-the-Drain AssessmentThe submitters indicated general support for the use of a down-the-drain model approach to estimate ecological exposure resulting from esfenvalerate uses which may travel down the drain and enter POTWs. However, wh ile some submitters support the use of the Exposure and Fate Assessment Screeni ng Tool (E-FAST) in a down-the-drain assessment, they indicated that methodology refinements are needed for down-the-drain13 assessments to be used in registration re view. Reference was made to previously submitted general comments stating submitters’ concerns with E-FAST Version 2.0. The submitters expressed an interest in work ing with EPA [both and the Office of Wastewater Management (O WM)] to refine the methodology for the down-the-drain assessments, particularly with respect to the use of stream dilution factors in a national

assessment and modifications to the met hodology for determining chronic and acute

estimated environmental concentrations. The submitters requested that the Agency collect information on the esfenvalerate use pa tterns that may result in down-the-drain exposure, the amount of esfenvalerate being discharged into sewers, as well as the environmental fate and aquatic toxicity data necessary to assess i ndoor uses and uses on

animals.

Response : EPA agrees that the methodology for a down-the-drain wastewater assessment, potentially using E-FAST, an Office of Chemical Safety and Pollution Prevention (OCSPP) model, would benefit fr om refinements and inputs from various entities including not only the submitters, but other EPA Offices and, potentially, other stakeholders. The Agency seeks to compar e existing and forthcoming monitoring data with the current model (E-FAST) and future, more refined down-the-drain models. To this end, OPP is working with individual s in the Office of Water (OW) regarding pyrethroids and available data specifically, as well as broader issues such as the use of a down-the-drain model for other pesticides with indoor uses. The Agency plans to use EFAST, including potential refinements, at th e time of the regist ration review risk

assessment. Available data and/or cons ervative assumptions would be used to parameterize the model.

The Agency recognizes the potential e xposure from down-the-drain sources of pyrethroids, and will continue to investigat e ways of more accurately evaluating these sources in fate and ecological exposure assessments. The inclusion of a down-the-drain assessment will be reflected in a revised problem formulation for esfenvalerate. Additionally, other sources, such as those identified by the Pyreth roid Working Group (PWG) in their 1/27/10 report “Problem Fo rmulation: Ecological Evaluation of Pyrethroids in the Urban Envir onment” will be considered.

Comment: Assessment of Cumulative Risks with Other PyrethroidsThe submitters stated that urban monitoring data indicate that mixtures of pyrethroids are contributing to pyrethroid-related toxicity in both the water column and sediments. They

stated that there is substantial evidence in the scientific literature to demonstrate the additive nature of pyrethroid toxicity to aqua tic organisms, and urge EPA to evaluate the cumulative risks of esfenvalerate with other pyrethroids.

Response: The Agency has evaluated the cumulative risks of other type s of pesticides

with common modes of action in its human h ealth risk assessments. These assessments have been challenging, even given that a singl e species (humans) is being assessed. EPA does not currently have the methodology to c onduct similar cumulative risk assessments for all of the non-human biological entitie s under the Agency’s purview. Although EPA14 agrees that an assessment of cumulative risk is a desirable goal, the Agency does not

believe the current state of the science can a ddress this issue quantitatively. However, EPA will consider open literature, modeling a nd other lines of evidence to qualitatively address the potential for cumulative effects in the ecological effects risk assessment.

Comment: Develop and Implement a Methodology Eval uating the Ecological Effects ofProduct SynergistsThe submitters stated that a methodology should be developed to evaluate the ecological effects of product synergists for the assessmen t of esfenvalerate, and for other chemicals as well, as a standard part of registration revi ew process. Submitters also stated that enduse products may be more toxic to aquatic or ganisms (than the pesticide active ingredient alone) because the products are formulated with synergists.

Response: EPA agrees that the presence of syne rgists may make an end-use product

more toxic than the active i ngredient alone. Available l iterature also suggests the potential for synergism in the environment ( e.g., Amweg et al. 2006, Weston et al. 2006, Amweg & Weston 2007, and Brander et al. 2009). The Agency routinely assesses synergistic formulations for potential exposure from spray drift and dire ct applications to water. Acute toxicity data on the formulati on is compared to potential exposure to spray drift. Esfenvalerate does have multiple active ingredient formulations that include piperonyl butoxide, MGK, and other pesticid es; however, the formulations are used to treat ant mounds, as surface sprays around homes , as crack-and-crevice treatments, and as wasp and hornet sprays. The spray drift a ssociated with these uses will be minimal and, therefore, a quantitative assessment of this potential aquatic exposure to formulations containing other specified active ingredients is not necessary.

Evaluating the effects of product synergists in aquatic environments , aside from direct applications to water, is not routinely done. It is important to r ecognize that the active ingredient and the synergist have differing fate properties and, therefore, would be expected to occur in the environment at diffe rent times and at diffe rent concentrations than present in the end-use product. Conseque ntly, it is necessary to have toxicology data

which allows the assessment of the level of synergy as the ratio of the pesticide andsynergist vary in the environment. Datasets which allow the calculation of the ‘pesticidesynergist interaction’ are not often available. EPA recognizes the limitations inherent in this approach and is looking into the acquis ition of data that would allow the evaluation of the effect of both synergist and active in gredient when present in the ecosystem. Evaluating the potential toxi c effects of the synergist include evaluating ecological effects data generated using e nd-use products and the active ingr edient in the presence of synergists, in addition to data for the active ingredient alone. At this time, EPA typically

has data for individual active i ngredients, as well as for the synergists alone, but few data

are available from which to draw conclusi ons regarding the potential effect of the combination. As stated above, the Agency is evaluating its options for obtaining data appropriate for this type of evaluation. However, EPA will not be requesting synergist data for esfenvalerate, since agricultural- use products with es fenvalerate are not formulated with synergists. For esfenvalera te, the environmental exposure for these co-15 formulated products only occurs through use of residential products via down-the-drain

exposure.

Comment: Request Additional Data as Needed for the Down-the-Drain Model andEcological Risk AssessmentComments were also received recommending that additional data be requested to inform the risk assessment, including acute and chr onic whole sediment to xicity data for both freshwater and estuarine/marine species a nd “all data to conduct the down-the-drain

assessment.”

Response: EPA agrees that sediment toxicity data are necessary for the ecological effects assessment of pyrethroids such as esfenva lerate. However, because the estimated environmental concentration (EEC) is greater than 10 percent of the median lethal concentration (LC 50 ) and the half-life is greater than 10 days, only chronic whole sediment data is being requested for freshwat er and estuarine/marine invertebrates. EPA will request a 96-hour Hyallela azteca water column test to better characterize this route of exposure for the most sensitive aquatic i nvertebrate species. Appropriate adjustments

will be made to the data needs sec tion in a revised problem formulation.

EPA will use the E-FAST down-the-drain model or a more refined version of the model for assessment of wastewater effluent expos ure. EPA will use all available data to determine the potential for esfenvalerate to reach ecological recepto rs through wastewater effluent. It is requested that any avai lable esfenvalerate monitoring data, or any information related to the fate of esfenvalerate in POTWs, be submitted at this time or at anytime that it is available during th e registration review process.

Comments from FIFRA Endangered Species Task Force (FESTF)

Comment : In response to the Summary Document, specifically to the need for additional information to complete an assessment on fe derally-listed threatened and endangered species that may be exposed to esfenvalerate, FESTF stated that its data on endangered species proximity contained in the FESTF Information Management System (FESTF IMS) submissions (2004, 05, 07) to the Agency “fulfill the data requirements... and provide the best available data necessary for the proximity an alysis of esfenvalerate use and listed species locatio ns.” FESTF stated that E. I. Dupont De Nemours and Co. is a current member of FESTF, and as such, is entitled to the FESTF data on federally-listed threatened and endangered species. Howeve r, LG Life Sciences Ltd. and Sumitomo Chemical Company Ltd. are not members and, ther efore, must offer to pay FESTF to rely on FESTF-submitted data or develop subs tantial similar data on their own.

Response: The Agency thanks FESTF for its comme nt and will consider this information as it conducts the registrati on review and makes its regi stration review decisions.16 Availability of Additional Agency Responses to Public Comments :

Comments relevant to human health have been addressed by the Health Effects Division’s document, Esfenvalerate: Response to Comments Received on the HED Scoping Document Prepared in Support of Registration Review

, dated April 21, 2010. Comments regarding the ecological fate or effects of esfenva lerate have been addressed by the Environmental Fate and Effects Division’s document, Response to Comments on the Registration Review- Preliminary Pr oblem Formulation for Ecological Risk, Environmental Fate, Endangered Species , and Drinking Water Assessment for Esfenvalerate , dated June 21, 2010. These documents are available in the esfenvalerate docket (EPA-HQ-OPP-2009-0301).

Next Steps :

o The Agency plans to issue a DCI in ear ly 2011, requiring the esfenvalerate studies needed to complete both the ecologica l and human health risk assessments.

o The Agency will conduct an ecological risk assessment, including an endangered species assessment, and a human health risk assessment for esfenvalerate.