Introduction:

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan (FWP) for the registration review of dichlorvos (DDVP). The Final Work Plan includes the expected registration review timeline. The FWP also a ddresses public comments received concerning the Preliminary Work Plan (PWP) in the Summary Document which was posted in the DDVP registration review docket (E PA-HQ-OPP-2009-0209) and any ot her comments concerning the 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 registration re view program and will review each registered pesticide every 15 years to determine whether it continues to meet the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) standard for registration. Changes in science, public policy, and pesticide use practices occur over time. The registra tion review program is intended to make sure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet that st atutory standard. The 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/

.

DDVP (Case #0310) is an organophosphate (OP) insecticide registered for livestock, commercial, and residential uses. These uses include cattle, poultr y, swine, agricultural equipment, feedlots, animal kennels, warehouses , mushroom houses, greenhouses, picnic areas, manure piles, refuse and solid waste sites, and residential dwellings.

Naled and trichlorfon are pestic ide active ingredients, which de grade to DDVP in food water,

and the environment. Naled and trichlorf on are each being assessed individually under registration review. The registra tion review of these active ingred ients will consider all residues of concern, including DDVP. The registration review of DDVP will consider DDVP exposure resulting from the use of naled, trichlorfon, and DDVP, itself.

Comments Received on the Preliminary Work Plan:

On June 24, 2009, EPA opened a 60-day public comme nt period for the registration review of DDVP. However, during this public comment period, the DDVP registration review docket was missing some supporting documents. After placing the supporting documents in the docket, the Agency reopened the comment period for an additional 30-day period on October 14, 2009. The Agency received comments from three parties. After reviewing the comments, in addition to the anticipated data needs listed in the DDVP PWP, the Agency now anticipates re questing aquatic toxicity studies performed with DDVP’s degrad ates of concern and the DDVP typical end-use product. The Agency anticipates requiring degrad ate data because there is no available toxicity information for the two DDVP environmental degr adates of concern: desmethyl DDVP, and 2, 2-dichloroacetic acid. The Agency also anti cipates requiring aquatic studies using the DDVP typical end-use product (TEP) because it is unknow n whether an ingredient in the current TEP

2other than the active ingredient could enhance toxicity to non-target aquatic organisms. The Agency has not altered the timeline detailed in the DDVP PWP.

In the PWP, EPA also solicited comments on three specific topics: environmental justice, water body impairment and trade irritant s. No comments or informa tion were received during the public comment period concerning these issues.

An overview of comments is presented in the “Summary of Comments Received during Docket Opening” section of this document. A more de tailed description of th e comments received, the Agency’s response to these comments, and rationales for additional data the Agency anticipates requiring in registration review is available in the separate response memoranda from the Agency’s Environmental Fate and Effects Divisi on (EFED) and Health Effects Division (HED) located in the DDVP registration review docket (EPA-HQ-OPP-2009-0209).

Summary of Comments Receive d During Docket Opening:

During the public comment period, the Agency received comments from the American Mushroom Institute, the Natural Resource De fense Council (NRDC), and AMVAC Chemical Corporation. The American Mushroom Institute requested that the mushroom use patterns and labeling changes required in the RED be maintained at the conc lusion of Registration Review. NRDC and the technical registrant, AMVAC Chemical Corporation, each provided comments regarding the Environmental Fate and Effects Division’s Problem Formulation, the Health Effects Division’s Scoping Document, and the PWP.

Some comments and responses have been described below. Commen ts relevant to human health have been addressed by the Heal th Effects Division’s document, Dichlorvos Response to comments on Preliminary Work Plan (S. Hummel, D35466112/22/2009). Comments regarding the ecological fate or effects of DDVP have been addressed by the Environmental Fate and Effects Division’s document, EFED Response to Public Comments for Dichlorvos (DDVP PF: Docket ID# EPA-HQ-OPP-2009-0209 (T. Mason and C. Wendel, D354655,12/21/2009)

. Both documents are available in the docket (EPA-HQ-OPP-2009-0209), available at regulations.gov.

Natural Resource Defense Council (NRDC)

Comment: NRDC is not familiar with an additional study that measures DDVP air concentrations in houses from use of pest strips and requests that this study be placed in the DDVP registration review docket.

Response: EPA required a special i ndoor air study in the DDVP reregistration eligibility decision (RED) data call-in (DCI). This study is a non-guideline study that will measure indoor air DDVP concentrations from the use of pest st rips in closets and cupboards in homes. The study was required in order to confirm the reside ntial pest-strip exposur e estimates that EPA made in the DDVP RED. The study is due in July 2010, and EPA will, consistent with FIFRA section 10, make the completed study available for review.

3Comment: NRDC urges EPA not to grant the registra nt’s request to waive the swine dermal study in the absence of reliable dat a showing that the metabolism in cattle is the same as in swine. We also request that EPA place the waiver petition into the regist ration review docket for public review and comment.

Response: On May 21, 2009, EPA denied AMVAC Chem ical Corporation’s request to waive the swine dermal study. The waiver petition a nd EPA’s response denying the request has been placed in the DDVP registration review docket.

Comment : NRDC refers to a previous petition where it noted that in an oyst er toxicity study, the end-use product was almost ten times more toxic than the technical product. NRDC is concerned that there are inert ingredients in the end use product that might be more toxic than the DDVP active ingredient. NRDC recommends that EPA determ ine the exact identity of the inerts in each of the products used in the oyster and mysid shri mp studies and examine the toxicity database for the inerts and call-in any needed toxicity data for these inerts. In addition, NRDC urges EPA to make public the identity of inerts and toxicity da ta relied upon by EPA to approve the inerts so the public in general and the world scientif ic community can exami ne the information.

Response: EPA has updated the DDVP registration review workplan to specify that it anticipates calling-in aquatic ecotoxicity data fo r the typical DDVP end-use product.

EPA also notes that it is currently moving forw ard on rulemaking to require the identities of potentially hazardous inert ingredients to appear on pesticide labels. This increased transparency will assist consumers and users of pesticides in making informed decisions and will better protect public health and the environment.

The Agency anticipates publishing an advance notice of proposed rulemaking in the Federal Register within the next few weeks. In it, EPA will discuss ideas for greater disclosure of hazardous inert ingredient identities as well as of inert ingredients in general. EPA believes one way of discouraging the use of th e more hazardous inert ingredients in pesticide formulations is by making their identities public.

Comment: NRDC requests that EPA include in the re gistration review docket all of the documents upon which it intends to rely in making its decision. As a matte r of convenience to the public, we recommend that all of the materials that were or are currently in all of the existing DDVP dockets (including EPA-HQ-OPP-2009-0629) be placed into the DDVP registration

review docket.

Response: Currently, there are three DDVP dockets available on regulations.gov:

1. EPA-HQ-OPP-2002-0302 – Dichlorvos (DDVP); Rere gistration Eligibility Decision (RED).

2. EPA-HQ-OPP-2006-0629 – DDVP Special Review.

43. EPA-HQ-OPP-2009-0209—DDVP Regist ration Review; Dichlorvos Docket opened for

Review and Comment.

Each of these dockets was set up for an indepe ndent purpose, and contains different documents according to that purpose; therefore, the Agency does not anticipate combining these materials

into one docket. All documents generated during registration re view will be posted in the DDVP registration review docket.

AMVAC Chemical Corporation

Comment: AMVAC continues to believe that some of the data that EPA has decided to require as part of the implementation of the Reregistration Eligibility Decision for DDVP are not needed for a proper and defensible risk assessment. AM VAC has previously requested that EPA waive certain data requirements, includi ng studies of dermal sensitiza tion, a dermal residue study in swine, and an indoor air exposure study. EPA has denied these waiver requests, but AMVAC intends to ask that each such denial be reconsidered. AMVAC will be basing these requests for reconsideration on the current availability of othe r data that are sufficient for risk assessment.

Response: In May 2008, EPA issued a Generic Data Call-In (GDCI) for the active ingredient, DDVP in connection with EPA’s RED. Among othe r things, that DCI required that a dermal magnitude of the residue study on swine and an i ndoor air study be submitted to the Agency. However, the GDCI did not require the dermal sensitization study referenced in AMVAC’s

comment. The GDCI established deadlines for submitting the residue study and the indoor air study of 24 months and 12 months, respectively. On August 29, 2008, AMVAC responded to the GDCI and requested waivers for the data requir ements for a dermal ma gnitude of the residue study on swine and an indoor air study. On J une 20, 2009, EPA sent a letter to AMVAC in which the Agency denied the waiver requests for these two studies. On September 30, 2009,

EPA informed AMVAC that it would extend the time period required in the May 2008 GDCI for submitting the studies. The Agency stated that the time periods of 24 and 12 months, respectively, that the Agency allows to conduct these studies would start from the date of the waiver denial, and therefore, the indoor ai r study is due on July 20, 2010, and the dermal magnitude of the residue study on sw ine is due on July 20, 2011.

If AMVAC fails to submit either of these studies on their respective due dates, EPA may issue a Notice of Intent to Suspend AMVAC’s DDVP regi strations or an order revoking or modifying associated DDVP tolerances, pursuant to FIFR A section 3(c)(2)(B) or FFDCA section 408(f).

AMVAC indicated in its comments that it intends to ask for reconsideration of EPA’s decision on its waiver request. Under the terms of the DDVP GDCI, a request fo r a waiver does not automatically extend the deadline for submission of required studies. In its discretion, EPA did

extend the deadlines for submission of the dermal magnitude of the residue study on swine and the indoor air study, as indicat ed above. However, should AMVAC file a request for reconsideration, such a request will not automatically extend the study submission deadlines. The deadlines may be extended by the Agency only if EPA determines that such extension is appropriate and states that in writing. To date, EPA has seen nothing in AMVAC’s prior waiver

5request that would justify any fu rther extension of th e deadlines for the submission of these two

studies. The deadlines for submission of the studi es to the Agency remain as stated in the Agency’s September 30, 2009 correspondence: July 20, 2010 for the indoor air study; and July 20, 2011 for the dermal magnitude of the residue study on swine.

Comment: AMVAC notes that EPA’s summary documen t includes a proposed requirement for a Foliar Dislodgeable Residue Dissipation stud y under Guideline 875.2100 to be utilized in assessing DDVP exposure from hand-held foggers. AMVAC believes that this is not necessary or appropriate. DDVP is not registered for out door use on any crop, and the lawn, turf, and

ornamental uses have all been cancelled. More over, although DDVP tec hnical products still permit use of liquid DDVP formulations in greenhouses, the use of hand-held foggers in greenhouses has been strictly prohibited.

Response: Currently the AMVAC techni cal label states, “[H]and-held foggers are prohibited in warehouses, greenhouses, and mushroom houses.” This current label language allows hand-held fogger use in other commercial locations and ther e are no data to evalua te this applicator exposure scenario. However, if AMVAC amends its label to prohibit a ll hand-held fogger use, EPA will no longer have to assess this use scen ario, and would no longer need to require the Foliar Dislodgeable Resi due Dissipation study.

Endocrine Disruptor Screening Program:

As required under FFDCA section 408(p), EP A has developed the Endocrine Disruptor Screening Program (EDSP) to determine whether 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 ap proach to making the statutorily required

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrog en, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough 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. Tier 2 testing is designed to identify a ny 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 is issu ing test orders/data call-ins for the first group of 67 chemicals, which contains 58 pesticid e active ingredients and 9 inert ingredients.

This list of chemicals was selected based on th e potential for human exposure through pathways such as food and water, residential activity, and ce rtain post-application agri cultural scenarios.

This list should not be construed as a lis t of known or likely endocrine disruptors.

DDVP is not among the group of 58 pesticide active ingredients on th e initial list to be screened under the EDSP. Under FFDCA sec. 408(p) the Agen cy must screen all pesticide chemicals. Accordingly, EPA anticipates issuing future EDSP orders/data call-ins for all Registration

6Review cases, including those for which EPA ha s already opened a Registration Review docket for a pesticide active ingredient.

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

Risk Assessment and Data Needs:

The Agency anticipates updating and revisi ng the ecological risk assessment for DDVP (including an endangered species risk assessmen t) and updating and revising the human health

risk assessment. Additional data that the Agency anticipates needing to complete these

assessments are identified below.

Ecological Risk:

• A national-level ecological risk assessmen t was completed in support of the 2006 DDVP RED. However, the Agency has not conduc ted a risk assessment that supports a complete endangered species determination. The ecological risk assessment planned during registration review will allow the Ag ency to determine whether DDVP’s use has “no effect” or “may affect” federally liste d threatened or endangered species (listed species) or their designated critical habita ts. 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.

• In order to complete a new comprehensiv e ecological assessment that includes an endangered species risk assessment, the Ag ency is anticipating requiring studies to reduce remaining uncertainties regarding DDVP volatilization, avian inhalation toxicity, potential acute oral toxicity to passerine birds, terrestrial plant toxicity, and aquatic toxicity to freshwater, estuarin e, and marine organisms.

• The Agency anticipates requiring volatility studies for DDVP because volatilization is potentially a major route of dissipation.

• The Agency is requesting an acute avian inhalation study to determine toxicological responses associated with the volatilizati on of DDVP. Submitted avian acute toxicity data also suggest that DDVP is very highly toxic to several species of birds on an acute oral basis; however, the resu lts may not reflect risks to passerine birds which have been identified to be more sensitive to pesticides in some cases.

• Terrestrial and aquatic plant studies are needed to assess direct and indirect environmental risks that DDVP may pose to endangered species.

7• There are no available toxicity information available for the DDVP degradates of concern and there is the potential of DDVP to drift to water bodies near application areas. Therefore, EPA will be submitting data call-in requests for all aquatic organisms (acute and chronic studies) for the degradates of concern, desmethyl DDVP and 2,2-

dichloroacetic acid

• There is uncertainty regarding the toxi city of the DDVP TEP. Therefore, EPA anticipates requesting acute eco toxicity studies for all aquatic organisms for the current DDVP TEP. The registrant may fulfill many of these data requirements with previous studies submitted to the Agency, if the end- use product used in these studies is still “typical.”

• The Agency anticipates needing the followi ng data in order to conduct a complete ecological risk assessment for DDVP, in cluding an endangered species assessment:

Ecological Toxicity Studies :

DDVP

o GDLN 850.1010 – Acute Toxicity Freshwater Invertebrates (Typical End-Use Product)

o GDLN 850.1025 – Acute Toxicity Estuarin e and Marine Organisms (Typical End-Use Product)

o GDLN 850.1035 – Acute Toxicity Estuarin e and Marine Organisms (Mysid) (Typical End-Use Product)

o GDLN 850.1075 – Freshwater Fish Toxi city (Typical End-Use Product)

o GDLN 850.2100 – Acute Avian Oral Toxici ty – Passerine (Technical Grade Active Ingredient)

o GDLNs 850.4100, 850.4150 – Terrestrial Plant T oxicity Test, Tier I, Seedling Emergence and Vegetative Vigor (Technical Grade Active Ingredient)

o GDLNs 850.4400 and 850.5400 – Aquatic Plant Growth (Tier I Aquatic Plant Growth) (Typical End-Use Product and Technical Grade Active Ingredient)

o Special Study – Acute Avian Inhalation Study (Technical Grade Active Ingredient)

Desmethyl DDVP

o GDLN 850.1010 – Acute Toxicity Freshwater Invertebrates

o GDLN 850.1025 – Acute Toxicity Estuarin e and Marine Organisms (Oyster)

o GDLN 850.1035 – Acute Toxicity Estuarin e and Marine Organisms (Mysid)

o GDLN 850.1075 – Freshwater Fish Toxicity

o GLDN 850.1300 – Aquatic Invertebrate Life-Cycle (Freshwater)

o GLDN 850.1350 – Aquatic Invertebra te Life-Cycle (Saltwater)

o GDLN 850.1400 – Fish Early-Life Stage (Freshwater)

o GDLNs 850.4400 and 850.5400 - Aquatic Plant Growth (Tier I Aquatic Plant Growth)

2,2-dichloroacetic acid

8o GDLN 850.1010 – Acute Toxicity Freshwater Invertebrates

o GDLN 850.1025 – Acute Toxicity Estuarin e and Marine Organisms (Oyster)

o GDLN 850.1035 – Acute Toxicity Estuarin e and Marine Organisms (Mysid)

o GDLN 850.1075 – Freshwat er Fish Toxicity

o GLDN 850.1300 – Aquatic Invertebra te Life-cycle (freshwater)

o GLDN 850.1350 – Aquatic Invertebra te Life-Cycle (Saltwater)

o GDLN 850.1400 – Fish Early-Life Stage (Freshwater)

o GDLNs 850.4400 and 850.5400 – Aquatic Plant Growth (Tier I Aquatic Plant Growth)

Environmental Fate Studies :

o GDLN 835.1410 – Volatility – Laboratory

o GLDN 835.8100 – Volatility – Field

Please refer to the document, Registration Review – Preliminary Problem Formulation for the Ecological Risk Assessment of Dichlorvos (DDVP) , May 14, 2009 and EFED Response to Public Comments for Dichlorvos (DDV P PF: Docket ID# EPA-HQ-OPP-2009-0209 (T. Mason and C. Wendel, D354655,12/21/2009)for a detailed discussion of the Agency’s anticipated ecological

risk and environmental fate assessment needs.

Human Health Risk:

• No effects on the immune system have been seen in the DDVP toxicity studies submitted to date; however, based on a new immunotoxi city data requirement for DDVP (GDLN 870.7800), the Agency expects to reevaluate the toxicity endpoints used for human health risk assessment purposes in the registra tion review of DDVP. Updated dietary, residential, aggregate, and occupational risk assessments may be required during registration review to reflect any t oxicology endpoint modifications.

• The Agency does not expect to conduct a dr inking water assessment (DWA) as part of registration review for DDVP because the curre nt labeled uses of DDVP are unlikely to result in exposure to drinking water. Ho wever, DDVP will be asse ssed in drinking water as part of the naled and trichl orfon registration review cases. In the event that two or all three of these pesticides can be used in the same use area, then the contribution of DDVP from each chemical present will be inco rporated in the DDVP human health risk

assessment.

• The dietary exposure database for DDVP is complete. In a 2007 DDVP dietary risk assessment (Morton, 2007), aggregate acute and chronic dietary exposure for food and drinking water did not exceed the Agency’s level of concern. The 2007 dietary risk assessment will be used in registration revi ew if recent monitoring data and usage data for DDVP, naled, and trichlorfon show that di etary exposure to DDVP has not increased.

• Residue chemistry data are adequate to suppor t the current food uses, with the exception of a dermal magnitude of the residue study for swine, which was required in the DDVP

9RED DCI and is due in July 2011. Adequate an alytical methods are available to enforce

the DDVP tolerances.

• The registrant has voluntarily amended its tech nical registration to te rminate the uses ofhand held foggers in mushroom houses, greenhouses, and warehouses. However, handheld foggers are not prohibited in othe r indoor commercial locations (e.g., indoor agricultural farm structures and tobacco proce ssing plants); therefore, data are expected to be needed to evaluate this applicat or exposure scenario unless all applicable registrations are amended to prohibit this ap plication method in a ll indoor locations.

• Should the Agency determine that new info rmation on DDVP is available which could potentially impact the OP cumulative risk asse ssment and result in a risk of concern, the Agency will revisit the cu mulative risk assessment.

• The Agency anticipates needi ng the following data in order to conduct a complete human

health effects risk assessment for dietar y (food and drinking wate r), residential, and occupational exposures to DDV P under registration review:

o GDLN 870.7800 Immunotoxicity Study

o GDLNs 875.1200, 875.1400, & 875.2100 – Indoor Dermal, Indoor Inhalation, and Post-Application Dermal and Inhala tion Exposure from DDVP Indoor HandHeld Fogger Use.

• Please refer to Dichlorvos (DDVP). Human Health Assessment Scoping Document in Support of Registration Review, May 6, 2009, available in the docket for a detailed discussion of the anticipated risk assessment and data needs for completing the human

health risk assessment.

Other Data Needs:

• GLDN 830.750 UV/Visible Light Ab sorption – this study is a new data requirement under 40 CFR part 158 (Product Chemistry Data Requirements) for registration of a pesticide (food and non-food uses). The Agency anticipates requiring this study to obtain basic information about the compound’s id entity/composition and the wavelengths at which the compound may be suscepti ble to photochemical degradation.

1011 Timeline:

The Agency has created the following estimated timeline for the completion of the DDVP registration review.

Registration Review for DDVP – Proj ected Registration Review Timeline

Activities Estimated

Year/Month Opening the Docket Open Docket and Public Comment Period 2009 – June

Close Public Comment 2009 – November 1

Case Development
Issue Final Work Plan (FWP) 2009 – December Issue Data Call-in (DCI) 2010 – July – September

Data Submission 2012 – July - September Open Public Comment Period for Preliminary Risk Assessments 2014 – April – June

Close Public Comment Period 2014 – July – September Registration Review Decision Open Public Comment Period for Proposed Registration Review

Decision 2014 – October –

December

Close Public Comment Period 2015 – January –

March

Final Registration Review D ecision & Begin Post-Decision Follow-up 2015

Total (years) 6

Next Steps:

As noted previously, the Agency anticipates requiring several ecologi cal effects and human health studies through a Data Call-In Notice, expected to be issued in 2010. This new information will be used to conduct comple te risk assessments for all DDVP uses.

1 On June 24, 2009, EPA opened an initial 60-day public comment period for the registration review of DDVP, which closed on August 24, 2009. However, during th e initial public comment period, the DDVP registration review docket was missing some supporting documents. The Agency reopened the comment period for an additional 30-day period on October 14, 2009, which closed on November 13, 2009.