2 INTRODUCTION

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan (FWP) for the registration review of diclosulam . This work plan addresses public comments received concerning the Preliminary Work Plan (PWP), which was posted in the diclosulam registration review docket (EPAHQ-OPP-2015-0285). Diclosulam is a broad spectrum herbicide and is a member of the triazolopyrimidine sulfonamide cla ss of pesticides. It is formulated as a water dispersible granular (WDG) in water soluble pack ets (WSP), and is currently registered for use on peanuts and soybeans; and used in impregnated dry bulk fertilizers.

The Agency is implementing the registration review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodentic ide Act (FIFRA), and will review each registered pesticide every 15 years to determine whether it continues to meet the FIFRA standard for registration. Changes in science, public policy, and pesticide use pract ices occur over time. The regist ration 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 the st atutory standard. The public phase of registration review begins when the initial docket is opened for each case. Inform ation 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 period fo r 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 comments. This secti on is followed by registration review planned data needs, risk assessments expected to be conducted, and the projected registration review timeline for diclosulam. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

The Agency published a Federal Register No tice on June 16, 2015 (80 FR 34408), announcing a proposal to voluntarily cancel the secti on 24(c) registrations, MO040001 and TN040005. These registrations are the only diclosulam re gistrations for use on cottonwood plantings.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60-day public comment period on the Dicl osulam Preliminary Work Plan, which opened on June 24, 2015 and closed on August 24, 2015, the Agency received three public comments. Comments were submitted by Dow AgroSciences LLC, the Center for Biological Diversity (CBD), and the FIFRA Endangered Species Task Force (FESTF), LLC. The comments do not address the timeline described in the PWP, but they do address the pl anned ecological risk assessment and data requirements. In the PWP, EPA also solicited comments on the specific topics of environmental justice, water quality concerns, and trade irritants, but no comments or info rmation were received on those issues.

1 http://www2.epa.gov/pesticide-reevaluation3 This section does not capture ever y comment made about the PWP nor all of the Agency’s responses. Summarized below are public comme nts that are of a broader regulat ory nature. Public comments and EPA responses in their entirety are located in the docket, EPA- HQ-OPP-2015-0285. Summarized public comments and Agency responses related to the anticip ated ecological risk asse ssment or data needs are
in the Response to Public Comments on: “ Registration Review – Problem Formulation for Environmental Fate, Ecological Risk and Endangered Species for Diclosulam (06/09/15; PC Code 129122; DP Barcode 424568 ).”

Comments submitted by FE STF in EPA-HQ-OPP-2015-0285-0013.

1. Comment: FESTF previously submitted data necessary to support the analysis of diclosulam use and listed species locations and potential exposure. In addition, FESTF commented that the technical registrant of diclosulam is a member of the FES TF (or a company having met its data compensation obligations) and is entitled to rely on FESTF data.

Response: The Agency thanks FESTF for its comment and will take this under consideration.

Comments submitted by CB D in EPA-HQ-OPP-2015-0285-0011.

2. Comment: Under the Endangered Species Act, it is EPA’s duty to consult with the U.S. Fish and Wildlife

Service and National Marine Fisheries Service on the re gistration review of diclosulam and approval of all diclosulam end-use product labels. In addition, the EPA must make de fensible “Not Likely to Adversely Affect” and “Likely to Adversely Affect” de terminations as a prere quisite for defensible “Jeopardy” and “No Jeopardy” determinations. EPA and the services must assess the adverse impacts of diclosulam in critical habitat.

Response : EPA has reviewed the comments from CBD on the registration review docket opening
for diclosulam and plans to address many of the con cerns raised by CBD as part of the implementation plan for assessing the risks of pesticides to listed species based on the recommendations of the April 2013 National Academ y of Sciences (NAS) re port. EPA will address concerns specific to diclosulam in connection with the development of its final registration review decision for this pesticide.

In November 2013, the EPA, along with the Services and the USDA, released a summary of their joint Interim Approaches for asse ssing risks to endangered and thre atened (listed) species from pesticides. The Interim Approaches were develope d jointly by the agencies in response to the NAS recommendations and reflect a common approach to risk assessment shared by the agencies as a way of addressing scientific differences between the EPA and the Services. The NAS report outlines recommendations on specific scientific and technical issues related to the development of pesticide
risk assessments that EPA and the Services must conduct in connection with their obligations under
the ESA and FIFRA.

The joint Interim Approaches were released prior to a stakeholder workshop held on November 15, 2013. In addition, the EPA presented the joint Inte rim Approaches at the December 2013 Pesticide Program Dialogue Committee (PPDC) and State- FIFRA Issues Research and Evaluation Group (SFIREG) meetings. The agencies also held stakeholder workshops in April and October 2014, allowing additional opportunities for stakeholde rs to comment on the Interim Approaches.4 Additional workshops are planned to enhance stake holder involvement. As part of a phased, iterative process for developing the Interim Approaches, th e agencies will also consider public comments on the Interim Approaches in conne ction with the development of upcoming registration review decisions. The details of the joint Inte rim Approaches are contained in the white paper

, Interim Approaches for National-Level Pesticide Endang ered Species Act Assessments Based on the Recommendations of the National Acade my of Sciences April 2013 Report , dated November 1, 2013.

Given that the agencies are continuing to develo p and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed sp ecies and their designated critical habitat, the ecological problem fo rmulation supporting this Final Wo rk Plan for diclosulam does not describe the specific ESA analysis, including effect s determinations for specific listed species or designated critical habitat, to be conducted dur ing registration review. In the ecological problem
formulation document for diclos ulam, EPA described the screen ing-level risk assessment to determine the potential effects of diclosulam on all taxa of non-targe t wildlife and plants, which will assume that listed species and their designated critical habitats may be present in the vicinity of the application of diclosulam. This screening-level assessment will allow EPA to focus its future evaluations on the types of species where the potential for e ffects exists once the scientific methods being developed by the agencies have been fully vetted. While the agencies continue to develop a common method for ESA analysis, the planned screen ing-level risk assessment for the registration
review of diclosulam will describe the level of ESA analysis completed for this particular registration review case. Once the agencies have fully developed and implemented the scientific methods necessary to complete risk assessments fo r endangered and threatened (listed) species and their designated critical habitats, these methods will be applied to subsequent analyses for diclosulam as part of comple ting this registration review.

PLANNED DATA NEEDS

Table 1 below summarizes the planned da ta needs for diclosulam based on the Registration Review: Problem Formulation for Environmental Fate , Ecological Risk and Endangered Species for Diclosulam
and the Response to Public Comments on: “ Registration Review – Problem Formulation for Environmental Fate, Ecological Risk and Endangered Species for Diclosulam (06/09/15; PC Code 129122; DP Barcode 424568 ).” The planned data needs have not changed from what was included in the PWP, but the estimated timeframe for the aerobic soil metabolism study and the test material for the three field and semi-field pollinator studies have been revised.5 Table 1: Planned Data Needs for th e Diclosulam Registration Review

Guideline

Number 2 Study Title 2 Test

Material Estimated Timeframe
(Months from receipt of DCI)

835.4100 Aerobic Soil Metabolism 3 TGAI 24

850.2300 Avian reproduction toxicity test, mallard

duck TGAI 24

850.1350 Invertebrate Lifecycle Toxicity test with a marine/estuarine invertebrate species TGAI 12

850.1400 Fish Early Life Stage Toxicity Test with a marine/estuarine fish species TGAI 12

850.1400 Fish Early Life Stage Toxicity Test with a freshwater fish species TGAI 12

Non-Guideline* Acute oral toxicity to adult honey bees TGAI 12 Non-Guideline* Acute oral toxicity to larval honey bees TGAI 12 Non-Guideline* Chronic oral toxicity to larval honey bees TGAI 12 Non-Guideline* Chronic oral toxicity to adult honey bees TGAI 12

Non-Guideline** Field trial of r esidues in pollen and nectar TEP 24

Non-Guideline** Semi-field te sting for pollinators TEP 24 850.3040** Field testing fo r pollinators TEP 24
TGAI = technical grade active ingred ient; TEP = typical end-use product *Tier 1 (Laboratory-based studies) **Tier 2 and 3 (Semi-field and full field colony-level studies) The need for a higher tier test for pollinators will be determined based upon lower-tiered tests and/or other lines of data and the need for a refined pollinator risk assessment.

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 di closulam. For human health, EPA
evaluated the status of the human health risk assess ments for diclosulam and determined that sufficient data are available to complete the risk assessment. In the Diclosulam: Human Health Assessment Scoping Document and Preliminary Human Health Ri sk Assessment in Support of Registration Review

, summarized in Table 2 below, the Agency evalua ted the hazard and exposure data and conducted occupational and residential exposure assessments, as needed, to estimate the risk to human health that will result from the currently registered uses of pesticides.

2 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850 – Ecological Effects Tests –

including renumbering and other designations or changes for so me guideline studies. See “Final Test Guidelines; OCSPP 850 Series; Notice of Availability” 77 FR 38282, June 27, 2012. http://www.regulations.gov /#!documentDetail;D=EPAHQ-OPPT-2009-0154-0028

3 Aerobic soil metabolism data are required for four soils, but are currently only available for three. In addition to the need for

data from an additional soil, there is uncertainty about the identity of unextracted residues in the three studied soils. Depending on results from the additional soil, further data may be needed for other soils. Guidance available at http://www.epa.gov/pesticide-sc ience-and-assessing-pesticide-risks/guidance- addressing-unextracted-pesticide-residues should be followed (particularly the use of a range of solvent sy stems) in order to properly evaluate residues that were not extracted from soils in the previous studies.6 Table 2 summarizes the planned registrati on review risk assessments based on the Problem Formulation for Environmental Fate, Ecological Risk and Endangered Species for Diclosulam and the completed registration review human health risk assessment based on the Diclosulam: Human Health Assessment Scoping Document and Preliminary Hu man Health Risk Assessment in Support of Registration Review. Table 2 has not changed from wh at was included in the PWP.

Table 2: Planned Risk A ssessments for the Diclosulam 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 Yes Additional data are required in order to conduct the ecological risk assessment.

Incidents Will check

for updates For a discussion of reported ecological inci dents for diclosulam, see page 18 of the

Problem Formulation.

Human Health Dietary Food Completed In support of Registration Review, an updated chronic dietary (food and drinking water) exposure and risk assessment was conducted . The chronic dietary (food and drinking water) exposure estimates are below the level of concern (<100% cPAD) for the general U.S. population and all population subgroups (<1% of the cPAD), except all infants at 1.2%. Therefore, the chronic dietary diclosulam risk estimates are not of concern. A dose and endpoint of concern attributable to a si ngle dose were not observed; therefore, an acute point of departure was not selected and an acute dietary exposure assessment is not required for diclosulam. Drinking water Completed

Occupational

Handlers (mixers, loaders, applicators) Completed In support of Registration Review, an updated occupational exposure assessment for
diclosulam was conducted for mixers/loaders of WSP formulations, mixer/loaders for impregnation of dry bulk fertilizers, and for a pplicators of spray and dry bulk fertilizer containing diclosulam. The assessment was ba sed on the maximum registered application rates. Occupational handlers are anticipated to have short- and intermediate-term dermal and inhalation exposures. No short- or inte rmediate-term dermal toxicological endpoints were identified so a quantitative dermal risk assessment was not conducted; dermal risk is not of concern. The occupational handler exposure and risk estimates indicate that the
short- and intermediate-term inhalation margins of exposure (MOEs) are not of concern (i.e., an MOE > the LOC of 100) at baseline personal protective equipment (PPE; i.e., no respirator).7 Post-application Completed The Agency did not conduct a quantitative post-appl ication inhalation risk assessment for performing post-application activities in previously treated fields. The Agency will
determine in future assessments whether data (i.e., flux studies, route-specific inhalation toxicological studies) or further analyses are required for specific chemicals. In addition, the Agency is continuing to evaluate the av ailable post-application inhalation exposure data generated by the Agricultural Reentry Task Force.

An inhalation exposure assessment was perform ed for occupational/commercial handlers, and MOEs are not of concern. Handler expos ure resulting from application of pesticides outdoors is likely to result in higher exposu re than post-application exposure. Therefore, it is expected that these handler inhalatio n exposure estimates would be protective of most occupational post-applicati on inhalation exposure scenarios.

No short- or intermediate-term dermal toxicological endpoints were identified for diclosulam, so a quantitative dermal post-a pplication risk assessment was not conducted;

dermal risk is not of concern.

Residential Handlers No There are no proposed or registered pr oducts containing diclosulam that would result in residential exposure. Therefore, a reside ntial exposure assessment was not performed. Post-application No Bystander/Spray

drift Completed A quantitative spray drift assessment was conducted for diclosulam. Incidental oral risk
estimates were evaluated. The incidental oral margins of exposure (MOEs) for children 1 to <2 years old were >270,000 at the field’s edge, and are not of concern.

Other Aggregate Completed An acute aggreg ate risk assessment was not performed because an endpoint of concern attributable to a single oral dose was not selected for any population subgroup (including infants and children). Short- and intermediate-term aggregate risk assessments were not performed because there are no registered r esidential non-food uses. Since there are no residential uses, the chronic dietary (food and water) exposure estimates represent chronic aggregate exposure. Therefore, the chronic aggregate risk estimates are not of

concern to EPA. Cumulative No Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to diclosulam and any other subs tances and diclosulam does not appear to produce a toxic metabolite produced by other substances. Tolerances Yes According to EPA’s Interim Guidance on Tolerance Expressions, the tolerance expressions for diclosulam should be revised as follows:

Under 40 CFR §180.543(a): “Tolerances are established for residues of diclosulam, including its metabolites and degradates, in or on the commodities in the table below. Compliance with the tolerance levels specifi ed in the table is to be determined by measuring only diclosulam [ N -(2,6-dichlorophenyl)-5-ethoxy-7-fluoro[1,2,4] triazolo[1,5-c]pyrimidine-2-sulfonamide ] in or on the following commodities:

Tolerance Summary for Diclosulam (40 CFR §180.543)
Commodity Established Tolerance (ppm) Comments

40 CFR §180.543: diclosulam [ N -(2,6-dichlorophenyl)-5-ethoxy-7-fluoro[1,2,4] triazolo[1,5- c ]pyrimidine-2-sulfonamide]

Peanut 0.02 Soybean, seed 0.028 Incidents Will check

for updates For a discussion of reported human incidents for diclosulam see page 11 of the Scoping

Document and the Diclosulam: Tier I Review of Human Incidents

.

TIMELINE

EPA has created the following estimated timeline fo r the completion of the diclosulam registration review in Table 3 below. The projected timeline has not changed since the PWP.

Table 3: Registration Review for Diclosulam – Projected Registration Review Timeline

Activities Estimated Date Opening the Docket Open Docket and 60-day Public Comment Period June 2015 – Completed Close Public Comment August 2015 – Completed Case Development

Final Work Plan December 2015 – Completed Issue DCI January-March 2016 Data Submission January-March 2018 60-day Public Comment Period for Draft Ecological Risk Assessment 4 July-September 2019 Registration Review Decision 60-day Public Comment Period for Proposed Regi stration Review Decision October – December

2020 Registration Review Decision and Begin Post-Decision Follow-up 2021 Total (years) 6

NEXT STEPS

As noted previously, the Agency plans to require several environmental fate and ecological effects studies for diclosulam through a Data Call-In Notice, expected to be issued in 2016.

4 The regulations governing Registration Review generally require the Agency to provide a public comment period of at least

30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pes ticides, the Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments.