2 INTRODUCTION

This is the Environmental Protection Agency’s (E PA or the Agency) Final Work Plan (FWP) for the registration review of ametryn. This wo rk plan addresses public comments received concerning the Preliminary Work Plan (PWP), which was posted in the ametryn registration review docket (EPA-HQ-OPP-2013-0249). Ametr yn is a triazine herbicide used for selective control of broadleaf and grassy weed s in corn, pineapple, and sugarcane . There are no nonagricultural or resident ial uses registered.

The Agency is implementing the registration revi ew program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) a nd will review each registered pesticide every 15 years to determine whether it continues to meet th e FIFRA standard for registration. Changes in scienc e, public policy, and pesticide us e practices occur over time. The registration review program is intended to make su re that, as the ability to assess risk evolves and as policies and practices change, al l registered pesticides continue to meet the statutory standard. The public phase of registration review begins wh en the initial docket is opened for each case. Information on this program is provided on the Agency’s website. 1

The FWP begins with any updates since the PWP wa s issued. Next is a summary of substantive comments received during the public comment peri od for the PWP concerning anticipated data needs, expected risk assessments, or the estimated timeline identified in the PWP, and a summary of the Agency’s responses to those comme nts. This section is followed by registration review planned data needs, risk assessments expected to be conducted, and the projected registration review timeline for ametryn. Last ly, there is a discussion of next steps.

UPDATES SINCE TH E PWP WAS ISSUED

The case number for ametryn was inaccurately list ed as # 7036 in the PWP. The FWP reflects the correct case number for ametryn, which is # 2010.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60-day public comment period on the ametryn Preliminary Work Plan, which opened on June 26, 2013, and closed on August 26, 2013, the Agency received four sets of public comments. The comments were submitted by the technical registrant for ametryn, Syngenta Crop Protection, LLC (Syngenta); the FIFRA En dangered Species Task Force (FESTF); a citizen; and the South Dakota Co rn Growers Association. The comments do not address the timeline identified in the PWP, but do address da ta needs and the planned ecological registration review risk assessment. Syngenta submitted one comment on the data requirements identified in the PWP, indicating it would submit a waiver for Guideline 870.7800 (Immunotoxicity). EPA will consider a request for a waiver when it is submitted; however, a request has yet to be

submitted and therefore Guideline 870.7800 remains a data requirement to support registration review. Syngenta also submitted a comment regarding the planned endangered species assessment, which is addressed in the Response to Public Comments on the Registration Review

1 http://www.epa.gov/oppsrrd1/registration_review/3 – Preliminary Problem Formulation for Ecolog ical Risk and Environmental Fate, Endangered Species, and Drinking Water Assessments for Ametryn.

The comments did not result in a ch ange to the planned data requi rements or registration review work plan described in the PWP. In the PW P, EPA also solicited comments on the specific topics of environmental justice, water quality concerns , and trade irritants, but no comments or

information were received on those issues.

Summarized below are substantive public comment s that concerned the anticipated registration

review data needs or are of a broader regulatory nature. Public comments and EPA responses in their entirety are located in the docke t, EPA-HQ-OPP-2013-0249. Summarized public comments and Agency responses related to the an ticipated ecological risk assessment or data

needs are in the Response to Public Comments on the Registration Review – Preliminary Problem Formulation for Ecological Risk and Environmental Fate, Endangered Species, and Drinking Water Assessments for Ametryn . This section does not address every comment

received.

Comments submitted by Mark Gross, Presiden t and Lisa Richardson, Executive Director,

South Dakota Corn Growers Asso ciation in EPA-HQ-OPP-2013-0249-0010.

1. Comment: Ametryn can be applied to corn safely and is most often app lied post-directly, under a crop’s canopy. It fills a sp ecific need for growe rs and without it, farmers’ options would

be limited.

Response: EPA will consider this comme nt during registration review.

Comments submitted by FE STF in EPA-HQ-OPP-2013-0249-0011.

2. Comment: The technical registrant for ametryn, as identified on the fact sheet included in the PWP, is Sygnenta, which is a FESTF member and is entitled to rely on FESTF data.

Response : EPA will consider this comme nt during registration review.

Comments submitted by Syng enta in EPA-HQ-OPP-2013-0249-0012.

3. Comment : On page 6 of the PWP and on page 2 of the BEAD Chemical Profile (BCP), EPA states that, “Ametryn can be applied as a pr e-emergence and as a post-emergence directed spray.” Syngenta requests that the PWP and the BCP be revised to state that ametryn can be applied as “a post-emergence directed spra y (corn) and broadcast spray (sugarcane).”

Response : The statement in the PWP and BCP is correct and will not be revised. The intent of the sentence was to discuss, in general terms, the different applicati on methods of ametryn. Individual product labels provide details on how the product must be used on specific crops.

4. Comment : Syngenta requests that it be allowe d to conduct Guideline 850.4500 (Algal Toxicity) and 850.4550 (Cyanobacteria Toxicity) with technical grade active ingredient (TGAI) rather than typical end use product (TEP).4 Response : Either TEP or TGAI can be used as th e test substance in the conduct of Guideline 850.4500 (Algal Toxicity) and 850.4550 (Cyanobacteria Toxicity).

5. Comment : In the Acute, Subchronic, and Chronic Toxi city Profile table on page 17 of the Ametryn: Human Health Risk Scoping Document in Support of Registration Review, the skin sensitization toxicity category is left blank. Syngenta requests that th e Scoping Document be revised to include “N/A” for the sk in sensization toxicity category.

Response : EPA acknowledges that because ametryn is not a skin sensitizer, the skin sensitization category on page 17 of the Scopi ng Document for ametryn is not applicable. Because the Scoping Document does not indicate that ametryn is a sk in sensitizer and the

inclusion of “N/A” would be an editorial rather than substantive cha nge, the Scoping Document

will not be revised.

6. Comment : Syngenta respectfully submits a crop matrix for ametryn.

Response : EPA thanks Syngenta for the detailed crop use information. EPA will consider this information prior to the conduct of the human health an d ecological preliminary risk assessments to be conducted in support of registration review.

PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for ametryn based on the Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species , and Human Health Drinking Water Exposure Assessments for Ametryn and Ametryn: Human Health Risk Scoping Document in Support of Registration Review . The planned data needs have not changed from what was included in the PWP; ho wever, as a result of a comment received, the

test substances in the table below have been modifi ed to indicate that either TEP or TGAI can be used as the test substance in producing da ta for Guideline 850.4500 (Algal Toxicity) and 850.4550 (Cyanobacteria Toxicity).

Table 1: Planned Data Needs for the Ametryn Registration Review

Guideline

Number 1,2 Study Title 1 Test Material Estimated

Timeframe

(Months from receipt of DCI)

835.2240 Photodegradation in water TGAI 12

835.4100 Aerobic soil metabolism TGAI 24
835.4300 Aerobic aquatic metabolism TGAI 24

850.4500 Algal toxicity TEP or TGAI 12

850.4550 Cyanobacteria toxicity TEP or TGAI 12
870.3465 90-day inhalation 3 TGAI 24
870.7800 Immunotoxicity 4 TGAI 12
TGAI = technical grade active ingred ient; TEP = typical end-use product5 1 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850 – Ecological Effects Tests – including renumbering and other designations or changes for some guideline studies. See “Final Test Guidelines; OCSPP 850 Series; Notice of Availability” 77 FR 38282, June 27, 2012. http://www.regulations.gov/#!documen tDetail;D=EPA-HQ-OPPT-2009-0154-0028

2 As noted in the PWP, Page 31 of the Problem Formulation incorrectly indicates environmental chemistry methods (ECM) and associated independent laboratory validation (ILV) for water (Guideline 850.6100) are needed for ametryn. Acceptable ECM and ILVs for soil, sediment, and water have been submitted for ametryn, and therefore, EPA does not plan to require Guideline 850.6100.

3 A 28-day inhalation toxicity study will be sufficient. Ther efore, the study duration can be reduced from 90 days to 28 days.

4 Recently, OPP published the findings of its retrospective analysis of immunotoxicity studies submitted to the Agency, concluding that none of the studies included in th e analysis resulted in a Poin t of Departure (POD) that is lower than the PODs selected from other available guideline toxicology studies ( http://www.epa.gov/pesticides/regulati ng/immunotoxicity-ret ro-analysis.pdf ). EPA will consider requests for waivers for this study, particularly in light of the retr ospective analysis. A weight-of-evidence rationale will be

considered relative to the chemical’s t oxicological profile, primary target organ system(s) and mode of toxic action, and any immuno-related data available from structurally-related compounds.

RISK ASSESSMENTS FOR REGISTRATION REVIEW

During registration review, the Agency will conduct a comprehensive ecological risk assessment, including an endangered species assessment, for all uses of am etryn. For human health, EPA will conduct revised dietary and occupational risk assessments during registration review. If toxicological endpoints or points of departure are revised, they will be considered in the new assessments, as well as any changes to the sta ndard operating procedures or default exposure assumptions.

Table 2 below summarizes the plan ned registration review risk assessments based on the EFED Problem Formulation and HED Scoping Document. The planned assessments have not changed

from what was included in the PWP.

Table 2: Planned Risk Assessments for the Ametryn Registration Review

Type of Risk Assessment Conduct? Notes

Ecological and Environmental Fate Comprehensive ecological (species to be assessed

include terrestrial and aquatic organisms), including endangered species Y Parent ametryn will be considered the stressor of concern for the terrestrial exposure assessment. For the aquatic exposure assessment, in the absence of data on the toxicity of degradates NOA 428383 and NOA 423271, these degradates and the parent ametryn will be considered the stressors of concern using the total toxic resi due (TTR) approach. For additional information, see page 25 of the Problem

Formulation.

Incidents Will check for updates No ecological incidents re ported for ametryn; see page 24 of the Problem Formulation.6 Table 2: Planned Risk Assessments for the Ametryn Registration Review Type of Risk Assessment Conduct? Notes

Human Health Dietary Food Y EPA will update the dietary assessment during registration review to ta ke into account any new toxicity or exposure data, cha nges to safety factors, or changes in standard risk assessment operating procedures. Drinking water N Occupational Handlers (mixers, loaders, applicators) Y EPA will update the occupational assessment during registration review to ta ke into account any new toxicity or exposure data, cha nges to safety factors, or changes in standard risk assessment operating procedures. Post-application Y

Residential Handlers N Ametryn is not regi stered for residential use, registered uses are not anticipated to result in residential exposure, and ther efore, a residential risk assessment is not required. Post-application N

Other Aggregate Y Evaluates the combined risk from dietary and residential exposures. Since there are no residential uses, EPA will update the aggregate assessment to take into account any changes to dietary risk estimates only.

Cumulative N Ametryn has not been identified as a member of a cumulative group that shares a common mechanism of toxicity.

Tolerances Y Tolerances for am etryn are established under 40 CFR §180.258. EPA will update the residue definition for the tolerance expression for ametryn in accordance with current policy on tolerance definitions.

Incidents Will check for updates For a discussion of reported human incidents for ametryn, see page 10 of the Scoping Document and

the Ametryn: Review of Human Incident Reports

.

TIMELINE

EPA has created the following estimated timeline for the completion of the ametryn registration review in Table 3 below. The projected timeline has not change d since the PWP.7 Table 3: Projected Ametryn Registration Review Timeline

Activities Estimated Date Opening the Docket Open Docket and 60-day Public Comment Period 2013 – June Close Public Comment 2013 – August Case Development

Final Work Plan 2013 – December Issue DCI 2014 July - September Data Submission 2016 July - September 60-day Public Comment Period for Draft Risk

Assessments 1 2018 January – March

Registration Review Decision 60-day Public Comment Period for Proposed Registration Review Decision 2018 July – September

Registration Review Decisi on and Begin Post-Decision Follow-up 2019

Total (years) 6

1 The regulations governing Registration Review require the Agency to provide a public co mment period of at least 30 calendar days for draft risk assessments; see 40 CFR Pa rt 155.53(c). The Agency pl ans to provide a 60 calendar day public comment period for draft risk assessm ents as a general standard of practice.

NEXT STEPS

As noted previously, the Agency plans to requir e several environmental fa te, ecological effects, and human health studies for ametryn through a Da ta Call-In Notice, exp ected to be issued by September 2014.