Introduction:

This is the Environmental Protection Agency’s (EPA) Final Work Plan for the registration review of methiocarb. This wo rk plan includes the expected registration review time line. The work plan also a ddresses public comments received concerning the Preliminary Work Plan in the Summary Document , which was posted in the initial registration review docket, or any other comments concerni ng initial docket postings.

The Summary Document provided information on what EPA knows about the pesticide 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 new registrati on review program, and plans to review each registered pesticide every 15 years to de termine whether it continues to meet the Federal Insecticide, Fungicide and Rodenticid e Act (FIFRA) standard for registration. Changes in science, public policy, and pesticid e use practices will occur over time. The registration review program is intended to ma ke sure that, as the ability to assess risk evolves and as policies and pract ices change, all registered pe sticides continue to meet that statutory standard. The public phase of registration review begins when the initial docket is opened for each case. Inform ation on this program is provided at: http://www.epa.gov/oppsrr d1/registration_review/

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Methiocarb is an N-methyl carbamate ins ecticide, acaricide, molluscicide and avian repellent registered for use to control sna ils, slugs, mites and insects on ornamentals, lawns, and non-bearing deciduous and nut trees. There are no food or feed uses for methiocarb. The wettable powder formulations of methiocarb are restricted use pesticides available only to professional appl icators and are applied by broadcast, foliar spray, and soil incorporation to ornamental plants and non-bearing deciduous and nut

trees. One formulation of methiocarb is a general use pesticide sold as solid bait products, which can be used by homeowners and which are sprinkled over ornamental plant and non-bearing tree foliage, or applie d to soil around plants grown in greenhouses, nurseries, or residential gardens. Potent ial metabolites of concern are methiocarb sulfoxide (MSO), methiocarb phenol (MP), and methiocarb sulfoxide phenol (MSOP). Methiocarb is a member of the N-methyl carb amate (NMC) class of chemicals that share a common mechanism of toxicity and inhibi t acetylcholinesterase by carbamylation of the serine hydroxyl group located in the active site of the enzyme. The “Revised NMethyl Carbamate Cumulative Risk Assessment” was completed in September 2007 (available in the doc ket EPA-HQ-OPP-2007-0935).

Comments Received on Preliminary Work Plan:

The Agency received three comments on the methiocarb docket during the 60-day public comment period, which began on June 23, 2010 and ended on August 23, 2010. The comments received do not change the data a nd risk assessment needs or the timeline

detailed in the Methiocarb PWP. An overview of comments is presented in the “Summary of Comments and Agency Responses” section of this document. This document finalizes the work plan for the methiocarb registration review process.

2Anticipated Risk Assessment and Data Needs:

The Agency anticipates conducting comprehe nsive human health and ecological risk assessments, including an endangered species assessment, for all uses of methiocarb and its metabolites of concern. Below is a summary of the issues relevant to the registration review process for methiocarb.

Ecological Risk:

• The most recent comprehensive ecological ri sk assessment for registered uses of methiocarb was conducted in 1994 in support of the Methiocarb Reregistration Eligibility Decision (RED). Acute levels of concern (LOC) were exceeded for birds, reptiles, mammals, and invertebrate s, and chronic risk LOC were exceeded for birds, fish, and aquatic-phase amphibians.

• The degradation of methiocarb in soils is not well-defined, and more data are

needed on aerobic soil metabolism.

• Data are needed for aerobic and anaerobic aquatic metabolism because use on ‘field grown ornamentals’ is not prec luded by current methiocarb labels, and

therefore must be assumed.

• A fish accumulation data requirement (Guideline 850.1730) was previously waived because methiocarb and its degradates were assumed to kill fish before

toxic residues could bioaccumulate. Ba sed on new guideline requirements, this study is anticipated to be required as pa rt of the registration review process.

• Toxicity data for methioicarb degrad ates (methiocarb sulfoxide (MSO), methiocarb phenol (MP), methiocarb sulfoxide phenol (MSOP), methiocarb sulfone (MSO 2 ), and methiocarb sulfone phenol (MSO 2 P) are lacking. The residues of concern for exposure and risk as sessment will be reconsidered prior to analysis. In the absence of confirmatory data indicating low toxicity concerns for the major degradates of methiocarb, they will be assumed of equal toxicity as the

parent.

• The Agency has not conducted a risk assessment that supports a complete endangered species determination for methio carb. The ecological risk assessment planned during registration review will a llow the Agency to determine whether methiocarb’s use has “no effect” or “may affect” federally listed threatened or endangered species (listed species) or their designated critical habitat. When an

assessment concludes that a pesticide’s use “may affect ” a listed species or its designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the Services), as appropriate.

• The Agency needs the following data in order to conduct a complete environmental fate and ecological risk assessment for parent methiocarb and its degradates, including a complete endangered species assessment.

Environmental Effects Studies:

o Guideline 850.1730 - Fish Bioconcentration Study

o Guideline 850.2300 - Avian Reproduction Test (Bobwhite Quail)

o Guideline 850.3030 - Honeybee Toxicity of Residues on Foliage

3o Guidelines 850.1075, 850.1025 and 850.1035, 850.1045, or 850.1055 - Estuarine/Marine Fish & Invertebrate Acute Toxicity Tests

o Guidelines 850.1300 & 850.1350 - Freshw ater & Estuarine/Marine Invertebrate Life Cycle Toxicity Test

o Guideline 850.1400 - Freshwater & Estu arine/Marine Fish Early Life Stage Toxicity Test

o Guidelines 850.4100 & 850.4150 - Terrestrial Plant Toxicity Tests (Tier I)

o Guideline 850.4400 - Aquatic Vasc ular Plant Growth (Tier I)

o Guideline 850.5400 - Aquatic Non-vasular Plant Growth (Tier I)

Environmental Fate Studies: These studies are needed to provide information on how, or by what mechanism, the pesticide degrades, the rate at whic h it degrades, where it goes, and what transformation products are formed once the compound is applied in the

environment.

o Guideline 835.4100 - Aerobic soil metabolism study

o Guideline 835.4300 - Aerobic aquatic metabolism study

o Guideline 835.4400 - Anaerobic aquatic metabolism study

o Guidelines 835.1230 & 1240 - Leaching and adsorption/desorption (for methiocarb, methiocarb phenol, methiocarb sulfoxide, methiocarb sulfoxide phenol).

o Guideline 835.6100 (Footnote 7) - Environmental chemistry analytical method in soil and independent laboratory validation

o Guideline 835.6200 (Footnote 7) - Environmental chemistry analytical method in water and independent laboratory validation

• Please refer to the Registration Review Preliminary Problem Formulation for the Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for Methiocarb in the methiocarb re gistration review docket (EPA-HQ-OPP-2010-0278)

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Human Health Risk:

• The most recent dietary and drinking water risk assessments for methiocarb were conducted for the February 1994 RED for methiocarb.

• The toxicology database for methiocarb is not considered complete for the purposes of registration review because of data gaps for a comparative ChE study in adults and offspring and an immunotoxicity study.

• A 2-generation reproduction study has been submitted and will be reviewed during registration review.

• Both acute and subchronic neurotoxicity st udies were previously identified as data gaps in the RED. However, informati on about N-methyl carbamate neurotoxicity

is now known from the EPA National Health and Environmental Effects Research Laboratory (NHEERL) studies and from th e carbamate cumulative assessment. Consequently, the Agency will require an acute comparative cholinesterase study for methiocarb, but does not antici pate requiring acute and subchronic neurotoxicity studies, or a de velopmental neurotoxicity study.

4• A drinking water exposure assessment for groundwater and surface water has not

been conducted and will be incl uded during regi stration review.

• Since there are no food or feed uses for methiocarb, dietary exposure from food is not expected. However, a decision on re sidues of concern in drinking water has not yet been made, and an updated dr inking water assessment, as well as aggregate risk assessment (due to po tential residential exposure), may be conducted to support the regist ration review of methiocarb.

• Both residential handler and residentia l postapplication expos ure are possible and neither has been quantitativ ely assessed. Residentia l handler exposure could occur from application of bait formulation to lawns and (non-food) gardens. Residential postapplication exposure c ould occur from: 1) contact with commercially grown nursery plants previous ly treated with methiocarb; 2) dermal and incidental oral exposure to children fr om contact with treated garden plants; and 3) dermal and incidental oral exposu re to children thr ough contact with or ingestion of pellets or granules of the ba it treatment. Both residential handler and postapplication exposures will be as sessed during registration review.

• The Agency anticipates conducting a re vised occupational handler exposure assessment and a postapplication assessment for methiocarb for all handler exposures, except the egg treatment use pa ttern, to reflect updates in Agency occupational/residential expos ure assessment methodologies.

• The Agency will require the following st udies in order to conduct a complete

human health assessment:

o Special Study - Comparativ e Cholinesterase Assay

o Guideline 870.7800 - Immunotoxicity

• Prior to a final registration review decision for methiocarb, the Agency will determine if there is any new information, such as new hazard or exposure data or information on changes to the use patt ern, which could affe ct the 2007 Revised

NMC Cumulative Risk Assessment. If s o, the Agency will revisit the cumulative

risk assessment.

• Please refer to the Methiocarb. Human Health Assessment Scoping Document in Support of Registration Review in the methiocarb regi stration review docket (EPA-OPPTS-OPP-2010-0278) for a detailed discussion of previous human

health assessments.

Other Anticipated Data Needs:

• Guideline 830.7050 UV/Visible Light Absorption – this study is a new data requirement under 40 CFR part 158 (Produc t Chemistry Data Requirements) for registration of a pesticide (food and non-food uses). The Agency will be 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.

5Endocrine Disruptor Screening Program (EDSP):

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 em ploys 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, or thyroid (E, A, or T) hormona l systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Ti er 2 testing is designed to identify any adverse endocrine related effects caused by th e substance, and esta blish a quantitative relationship between the dose a nd 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.

Methiocarb was one of several pest icides removed from the initial list of pesticides to be screened because changes in their use and a pplication methods eliminated the potential for exposure in one or more pathways. Specifically, the remaining agricultural uses for methiocarb are granular applications in nurseries and greenhouses, and current registrations no longer include use on food crops. Although methiocarb is only present in two exposure pathways (water and resident ial), under FFDCA sec. 408(p) the Agency must screen all pesticide chemicals. Acco rdingly, EPA anticipates issuing future EDSP

orders/data call-ins for all Re gistration Review cases, incl uding those for which EPA has already opened a Registration Review docke t for a pesticide active ingredient.

For further information on the status of the ED SP, the policies and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/.

Timeline:

EPA has created the following estimated timeline for the completion of the methiocarb registration review.

Registration Review for Methiocarb – Pr ojected Registration Review Timeline

Activities Estimated Date Opening the docket Open Docket and Public Comment Period 2010 – June

6Close Public Comment 2010 – August Case Development

Final Work Plan 2010 – December

Issue DCI 2011 – Jul.-Sept.

Data Submission 2013 – Jul.-Sept. Open Public Comment Period for Preliminary Risk Assessments 2015 – Jan.-Mar.

Close Public Comment Period 2015 – Apr.-Jun. Registration Review Decision Open Public Comment Period for Proposed Registration Review

Decision 2015 – Jul.-Sept.

Close Public Comment Period 2015 – Oct.-Dec. Final Registration Review Deci sion and Begin Post-Decision Follow-up 2016

Total (years) 6

Summary of Comments Receive d During Docket Opening:

The Agency received comments from the Physicians Committee for Responsible Medicine (PCRM), the American Bird Cons ervancy (ABC), and the FIFRA Endangered Species Task Force (FESTF) relating to the environmental fate and ecological risk problem formulation for the Regi stration Review of methiocarb.

PCRM Comments PCRM commented that the Agency could reduce the number of animals tested by following a “limit test” approach, and coul d use a Quantitative Structure Activity Relationship (Q)SAR data in addition to laboratory data.

EPA Response The Agency agrees that a limit test approach could be used to fulfill the requirement if conducted according to guideline 850.1075 and cl assified as acceptable. The Agency is actively working with other agencies to develop a (Q)SAR guidance document and will

consider its final recommendations when conducting ecological risk assessments.

ABC Comments ABC commented that that the Agency should require several additional avian studies, including studies with passerine species and with degradates of the parent methiocarb compound. ABC also commented that backyard uses and the egg use of methiocarb should be suspended to protect birds.

EPA Response The Agency believes that the data it is requ iring with avian species will be adequate for assessing potential risks of methiocarb to th is taxa. The Agency concurs with ABC that an avian reproduction study is needed for quail, and this requirement was included in both the Preliminary and Final Work Plans. In addition, the Agency will review relevant databases and open literature for any additi onal data or informa tion that addresses concerns raised by the ABC, (such as avian de velopmental effects or the toxicity of any

7of the methiocarb degradates). In the absence of confirmatory data, the Agency will consider methiocarb degradates to be of equal toxicity to parent methiocarb.

The registration review schedul e is designed to allow EPA to obtain and review pertinent

new information in order to make a t horough and informed decision regarding the benefits of the use of compounds weighed agains t the risks to all non-t arget species. The schedule also allows the Agency to conduct an assessment for any endangered species which might be at risk from the use of this compound.

Regarding ABC’s comment to suspend certain uses of methiocarb, FIFRA gives EPA the authority to suspend use of pesticide under very specific ci rcumstances which are: (1) imminent hazard [section 6(c)] or (2) failure to submit additional data [3(c)(2)(B)]. EPA

did not review ABC’s incident database during the development of the RED, but the Agency did review other bird incident databases during that period. Although ABC requested suspension for the use of methiocarb, ABC did not provide, nor does EPA have, any new information that supports an imminent hazard fi nding, or a basis for suspending methiocarb registrations under th e authority of sec tion 3(c)(2)(B).

Comments from the FIFRA Endangere d Special Task Force (FESTF) FESTF suggested the Agency use FESTF data for its endangered species assessment of methiocarb, and made an additional comment re garding cost sharing for development of data on endangered species.

EPA Response: The Agency thanks FESTF for its comments, and will consider this information as it conducts the regist ration review and makes its decision.

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

Next Steps: A Data Call-In will be developed regarding data gaps listed under the “Risk Assessment and Data Needs” section. An ecological ri sk assessment, which includes an endangered species assessment, will be conducted. A drinking water assessment, as well as an aggregate risk assessment may be conducted, an d the Agency anticipates assessing both residential handler and postapplicatio n exposure during registration review.

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