2 INTRODUCTION

This is the Environmental Protection Agency’s (E PA or the Agency) Final Work Plan (FWP) for the registration review of simazine. This wo rk plan addresses public comments received concerning the Preliminary Work Plan (PWP), which was posted in the simazine registration review docket (EPA-HQ-OPP-2013-0251). Simazine is a non-selective systemic triazine herbicide registered for use for pre- and post- emergent applications to control annual and perennial grasses and broadleaf weeds on a variet y of crops, such as oranges and corn; and nonagricultural use sites, such as residential turf. Fo r human health risk assessment, simazine is part of the triazine common mechanism group base d on a common toxicity end-point and known mechanism of toxicity. The tr iazine common mechanism group cons ists of the pesticide active ingredients atrazine, simazine , propazine, and the metabolites desethyl-s-atrazine (DEA), desisopropyl-s-atrazine (DIA), a nd diaminochlorotriazine (DACT). 1

The Agency is implementing the registration revi ew program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and will review each registered pesticide every 15 years to determine whether it continues to meet th e FIFRA standard for registration. Changes in science, public policy, and pesticide use 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. 2

The FWP begins with any updates since the PWP wa s issued. Next is a summary of a comment, which is not addressed in a separate respone to comments document or elsewhere in this document, and the Agency’s response. This se ction is followed by registration review planned data needs, risk assessments expected to be conducted, and the projec ted registration review timeline for simazine. Lastly, there is a discussion of next steps.

UPDATES SINCE TH E PWP WAS ISSUED

The case number for simazine was erroneously lis ted as # 7280 in the PWP. The FWP reflects the accurate case number for simazine, which is # 70.

The table of data requirements has been modifi ed to clarify that environmental chemistry methods (ECM) and associated independent labo ratory validations (ILVs) for soil are required for parent simazine as well as the degr adates hydroxysimazine, DIA, and DACT.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60-day public comment period on th e Simazine Preliminary Work Plan, which opened on June 26, 2013 and closed on August 26, 2013, the Agency received 14 sets of public comments. The comments were submitted by a citizen, individual growers, registrants

1 There are other triazine pesticides, such as ametryn, prometryn, and prometon, but they are excluded from the

triazine common mechanis m group because they do not share the same toxicity profile. ( Triazine Cumulative

Risk Assessment . J. Morales. March 28, 2006.)

2 http://www.epa.gov/oppsrrd1/registration_review/3 [Syngenta Crop Protection, LLC (Syngenta) and Reg West Compa ny, LLC], the FIFRA Endangered Species Task Force (FESTF), and trad e associations (grower and industry groups).

The comments received do not address the timeline or data requirement described in the PWP, but do address the planned ecological risk asse ssment. In the PWP, EPA also solicited comments on the specific topics of environmenta l justice, water quality concerns, and trade irritants, but no comments or inform ation were received on those issues.

Two commenters, an individual grower and a citizen, submitted comments indicating that

simazine use should be discontinued because th ere are safer alternativ es. Other individual growers and the following grower groups, trade associations, and industry groups commented on the importance of simazine to growers, describi ng, among other things, its importance as a tool in weed management and weed resistance, a nd stewardship efforts used to limit potential nontarget exposures (South Dakota Corn Grow ers Association; Maryland Grain Growers Association; Illinois Farm Bureau; Ohio Corn a nd Wheat Growers Associat ion; Illinois Soybean Association; Triazine Network; and Ch emical Industry Council of Illinois).

Syngenta submitted technical comments on the Problem Formulation and Scoping Document; recommended corrections to the use and usag e information described in the PWP and BEAD Chemical Profile (BCP); and submitted a detailed crop matrix describing the use parameters of simazine (e.g., application rate, timing, etc.). FESTF commented that Syngenta is a member of FESTF and is entitled to rely on FESTF data to help address species proximity to simazine use sites for the planned endangered species assessmen t. EPA will consider these comments during registration review.

Public comments and EPA responses in their en tirety are located in the docket, EPA-HQ-OPP2013-0251. Summarized public comments and Agency responses related to the anticipated ecological risk assessment are in the EFED Response to Comments Submitted by Syngenta Crop Protection, LLC. Concerning the Re gistration Review of Simazine

, while those rele vant to the anticpated human health risk assessment are in the Simazine: Responses to Comments on Human Health Assessment Scoping Document in Support of Registration Review. Summarized public comments and responses on simazine use and usage unformation described in the PWP and BEAD Chemical Profile (BCP) are in the BEAD Responses to the Comments on the Simazine BEAD Chemical Profile and Preliminary Work Plan

.

This section does not capture every comment made about the PWP nor all of the Agency’s responses. Summarized below is a public comme nt not addressed in the Agency’s response to

comments documents or elsewhere in this document.

Comment submitted by Reg We st, LLC in EPA-HQ-OPP-2013-0251-0013.

Comment : There is a registered use pattern of si mazine, as an algicide in aquariums and containerized ornamental fish pon ds and fountains of 1000 gallons or less, not mentioned in either the “Human Health Risk Scoping Docume nt in Support of Registration Review” or the “Simazine Preliminary Work Plan.” In addition, the “Simazine Pr eliminary Work Plan” states there are 22 Section 3 regi stration, and there are 23 Section 3 registrations.

Response : EPA is aware that there is an aquarium /ornamental pond use of simazine, and this use4 is listed on page 6 of the PWP. There are curre ntly 24 Section 3 registrations for simazine. At the time of PWP completion, there were 22 Section 3 registrations. All of the active registrations will be considered in the registration revi ew preliminary risk assessments (PRAs).

PLANNED DATA NEEDS

Table 1 below summarizes planne d data needs for simazine. Fo r additional discussion of the data needs, see the Registration Review – Preliminary Pr oblem Formulation for the Ecological Risk Assessment for Simazine and Atrazine, Propazine and Simazine. Human Health Risk Scoping Document in Support of Registration Review . The planned data needs have not changed from what was included in the PWP, but th e test substances have been clarified.

Table 1: Planned Data Needs for the Simazine Registration Review

Guideline

Number 1 Study Title 1 Test Material Estimated

Timeframe

(Months from receipt of DCI)

850.6100 Environmental chemistry methods (ECM) and associated independent laboratory validation (ILV)

for soil 2 TGAI and Degradates 3 12

TGAI = technical grade active ingredient

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 Av ailability” 77 FR 38282 , June 27, 2012. http://www.regulations.gov/#!documen tDetail;D=EPA-HQ-OPPT-2009-0154-0028

2 ECM and ILVs are used in the testi ng and identification of chemicals.

3 ECM and ILVs for soil are required for parent simazine and degradates hydroxysimazine, DIA, and DACT.

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 si mazine. For human health, EPA will conduct revised dietary, residential, occupa tional, and cumulative risk assessments during registration review. If toxicolo gical endpoints or points of depa rture are revised, they will be considered in the new assessments, as well as an y changes to the standard operating procedures or default exposure assumptions.

Table 2 below summarizes the planned registrati on review risk assessments based on the EFED Problem Formulation and HED Scoping Docume nt and the planned assessments have not changed from what was included in the PWP.5 Table 2: Planned Risk Assessments for the Simazine 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 The stressors of concern for terrestrial organisms are parent simazine and the de gradate DIA. The stressor of concern for aquatic organisms is parent simazine alone. For additional information, see page 23 of the

Problem Formulation.

Incidents Will check for updates For a discussion of reporte d ecological incidents for simazine, see page 21 of the Problem Formulation.

Human Health Dietary Food Y During registration review, an updated dietary assessment will be conducted to include any updates to toxicological endpoints, dietary exposure estimates, and changes to assessment SOPs. Drinking water Y EPA plans to use the data collected in the SMP in its drinking water assessment for simazine during registration review. EPA also plans to use data

collected in the Atrazine Monitoring Program (AMP) in the drinking water assessment for simazine, as simazine is also detected in water samples analyzed

for the AMP. Occupational Handlers (mixers, loaders, applicators) Y Since the most recent occupational risk assessment for simazine was conducted, EPA finalized new occupational risk assessment standard operating procedures (SOPs), includi ng new potential exposure scenarios applicable to simazine that were not previously assessed (e.g. ha ndheld equipment for turf and ornamentals). During registration review, EPA plans to update all releva nt occupational exposure scenarios, along with an y changes to toxicity endpoints and/or safety factors. Post-application Y

Residential

Handlers Y Since the most recent residential assessment for simazine was conducted, new residential risk assessment procedures c ontaining add itional turf scenarios have been finalized. During registration review, EPA plans to update all relevant residential handler and post-applicati on assessments, along with any changes to toxicity endpoints and/or safety

factors. Post-application YDocket Number EPA-HQ-OPP-2013-0251 www.regulations.gov

Table 2: Planned Risk Assessments for the Simazine Registration Review

Type of Risk Assessment Conduct? Notes

Human Health

Other Aggregate Y Evaluates the combined risk from dietary and residential exposures. Cumulative Y An assessment of the triazine cumulative group is planned as part of registration review.

Tolerances Y Tolerances ar e established under 40 CFR §180.213

for the combined residues of simazine and its two chlorinated metabolites in/on a variety of crops and livestock commodities. EPA plans to update the

residue definition for the tolerance expression for simazine in accordance with current policy on

tolerance definitions.

Incidents Will check for updates For a discussion of reported human incidents for simazine, see page 12 of the Scoping Document and

the Atrazine, Propazine, and Simazine: Review of Human Incident Reports

.

TIMELINE

EPA has created the following estimated timeline for the completion of the simazine registration review in Table 3 below. The projecte d timeline has not ch anged since the PWP

Registration Review for Simazine – Pr ojected 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 – Decmeber Issue DCI 2014 – July - September 60-day Public Comment Period for Draft Risk Assessments 1,2 2015 – April - June Data Submission 2016 – July - September Registration Review Decision 60-day Public Comment Period fo r Proposed Registration Review

Decision 2015 – Oct. - Dec.

Registration Review Decision and Begin Post-Decision Follow-up 2016 Total (years) 3

1 The registration review schedule for most conventional pesticides includes a 6 month period after the Final Work Plan to issue a data call-in and then an appropriate time period for the required data to be submitted to EPA. However, because the one data requirement for simazine, Guideline 850.6100 (environmental chemistry methods and associated independent laboratory validation for soil) , will not affect the prelim inary risk assessments for simazine registration review, the schedule has been modified as appropriate.2 2 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 pesticides, the Agency plans to provide a 60 calendar day public comment period for draft risk assessments.

NEXT STEPS

As noted previously, the Agency plans to requ ire one study for simazine through a Data Call-In Notice, expected to be issued by September 2014.