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INTRODUCTION

This is the Environm ental Protection Agency’s (EPA or the Agency ) Final Work Plan (FWP) for the registration review of dikegulac sodium. This work plan addresses public comments received concerning the Preliminary Work Plan (PWP), which was posted in the dikegulac sodium registration review docket (EPA

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- sodium is a plant growth regulator that was first register ed in 1978. It is registered for use on ornamentals, nursery crops, and trees to reduce growth, flowering, and/or fruit set. There are residential uses of dikegulac sodium.

Three end

- use products containing dikegulac

- sodium are currently registered for u se in the United

States. Dikegulac

- sodium was previously assessed at the time of the development of the Reregistration Eligibility Decision (RED) in 2007.

The Agency is implementing the registration review 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 the FIFRA standard for registration. Changes in science, public policy, and pesticide use pract ices occur over time. The registration 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 statutory standard. The public phase of regist ration review begins when the initial docket is opened for each case. Informatio n on this program is provided on the Agency’s website

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The FWP begins with any updates since the PWP was issued. Next is a summary of substantive

comments received during t he public comment period 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 response s to th o se comments

. This section is followed by registration review planned
data needs, risk assessments expected to be conducted , and the projected registration review timeline

for dikegulac sodium. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

There are no additional updates on dikegula c sodium since the PWP.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60

- day public comment period on the Dikegulac S odium Preliminary Work Plan , which opened on December 19, 2014 and closed on February 19, 2015 , the Agency received two public comments. Comments were submitted by the FIFRA Endangere d Species Tas k Force (FESTF) and T

he Center for Biological Diversity (CBD) . The comments do not address the timeline described in the PWP, but they do address the planned ecological and human health risk assessments 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 information were received on

those issues.

Summarized below are public comments received in response to the Dikegulac Sodium Preliminary

Work Plan

. Public comments in their entirety are located in the docket, EPA

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1 http://www.epa.gov/oppsrrd1/registration_review/3

Comments submitted by the FIFRA Endangered Species Task Force (FESTF) in EPA

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Comment: FESTF submitted a comment informing the Agency that the technical registrant of dikegulac sodium

, PBI/Gordon Corporation

, is a member of the FESTF (or a company having met its data compensation obligations)

and is entit led to rely on FESTF data.

Response: The Agency thanks FESTF for its comment.

Comments submitted by the Center for Biological Diversity (CBD) in EPA

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Comment: The Center for Biological Diversity’s (CBD) comments focus on the EPA’s duty to consult with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (the Services) on the registration review of dikegulac sodium in accordance with the Endangered Species Act (ESA). The CBD comments mention various aspects of the risk assessment process, including use of the best available data to develop endangered species risk assessments, and evaluation of effects on endangered and threatened species and their designated critical habitat. CBD also expresses concern regarding the rigor of the Agency’s preliminary determinations regarding the effects of dikegulac

sodium on endangered and threatened (listed) species and their designated critical habitat for the dikegulac sodium registration review

.

Response: EPA has reviewed the comments from CBD on the registration review docket opening

for dikegulac sodium and plans to address many of the concerns raised by CBD as part of the implementation pl an for assessing the risks of pesticides to listed species based on the recommendations of the April 2013 National Academy of Sciences (NAS) report. EPA will address concerns specific to dikegulac sodium in connection with the development of its final reg istration

review decision for dikegulac sodium

.

In November 2013, the EPA, along with the Services and the USDA, released a summary of their joint Interim Approaches for assessing risks to endangered and threatened (listed) species from pesticides. The I nterim Approaches were developed jointly by the agencies in response to the National Academy of Sciences’ (NAS) recommendations and reflect a common approach to risk assessment shared by the agencies as a way of addressing scientific differences between th e 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 Interim Approaches at the December 2013 Pesticide Program Dialogue Committee (PPDC) and State

- FIFRA Issues Research and Evaluation Group (SFIREG) meetings. The agencies also held a stakeholder workshop in April and October 2014, allowing additional opportunities for stakeholders to comment on the Interim Approaches. Additional workshops are planned to enhance stakeholder involvement. As part of a phased, iterative process for developing the Interim Approaches, the agencies will also consider public comments on the Interim Approaches in connection with the development of upcoming Registration Review dec isions. The details of the joint Interim Approaches are contained in the white paper “Interim Approaches for National

- Level Pesticide Endangered Species Act Assessments4

Based on the Recommendations of the National Academy of Sciences April 2013 Report,” dated November 1, 2013.

Given that the agencies are continuing to develop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habitat, the ecological probl em formulation supporting this Final Work Plan for dikegulac sodium does not describe the specific ESA analysis, including effects determinations for specific listed species or designated critical habitat, to be conducted during registration review. In th e ecological problem formulation document for dikegulac sodium , EPA described the screening

- level risk assessment to determine the potential effects of dikegulac sodium on all taxa of non

- target wildlife and plants, which will assume that listed species and their designated critical habitats may be present in the vicinity of the application of dikegulac sodium . This screening

- level assessment will allow

EPA to focus i ts future evaluations on the types of species where the potential for effects 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 s creening

- level risk assessment for the registration review of dikegulac sodium 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 n ecessary to complete risk assessments for endangered and threatened (listed) species and their designated critical habitats, these methods will be applied to subsequent analyses for dikegulac sodium as part of completing this registration review.5

PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for dikegulac sodium based on the EFED Registration Review Problem Formulation for Dikegulac

- sodium and Dikegulac Sodium Human Health Scoping Document and Preliminary Risk Assessment. The planned data needs have not changed from what was

included in the PWP

.

Table 1: Planned Data Needs for the Dikegulac Sodium Registration Review

Guideline

Number 2 Study Title 1 Test Material Estimated

Timeframe (Months from receipt of DCI)
Anticipated Data Needs for the Parent Dikegulac Sodium

Non

- guideline Honey bee acute oral toxicity TGAI 12

Non

- guideline Honey bee acute larval toxicity TGAI 12

Non

- guideline Honey bee chronic larval toxicity TGAI 12

Non

- guideline Honey bee adult chronic 10

- day toxicity TGAI 12

RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent comprehensive human health and ecological risk assessments for dikegulac sodium were completed in 2006 in preparation for the Reregistration Eligibility Decision. Findings and

c onclusions from these risk assessments are summarized in the Dikegulac Sodium: Human Health Scoping Document and Preliminary Risk Assessment and the EFED Registration Review Problem Formulation for Dikegulac

- sodium.

During registration review, the Agency anticipates the need for additional data to allow for a more comprehensive evaluation of potential effects to honey bees. For human health, no new data are expected to be required to support the registration review o f this pesticide. There are no hazards associated with dikegulac sodium at doses relevant to humans; therefore, a qualitative approach to risk assessment is appropriate. The Dikegulac Sodium Human Health Scoping Document and Preliminary

Risk Assessment i s expected to serve as the preliminary risk assessment for the purpose of registration

review. EPA believes that there are no human health risks of concern associated with the currently registered uses of dikegulac sodium.

Table 4 below summarizes the anticipated registration review risk assessments based on the EFED Problem Formulation and HED Scoping Document.

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 som e guideline studies. See “Final Test Guidelines; OCSPP 850 Series; Notice of Availability” 77 FR 38282, June 27, 2012. http://www.regulations.gov/#!documentDeta il;D=EPA

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Table 4: Planned Risk Assessments for the Dikegulac Sodium Registration Review

Type of Risk Assessment Conduct? Notes

Ecological and Environmental Fate Comprehensive ecological (species to be assessed include terrestrial and aquatic organisms) No Ecological risk conclusions in the RED are unchanged

and will not be reassessed. The RED determined that all potential risks to aquatic organisms and plants were below the Agency’s level of concern (LOC). All potential risks to terrestrial organisms were a lso below the Agency’s LOC, except for semi

- aquatic non

- listed and listed plants. However, a more comprehensive evaluation of potential effects to honey bees is anticipated. Risks to federally listed species will be

reevaluated.

Incidents Will check for updates As of July 2014, there were no ecological incidents

reported in EIIS or AIMS for dikegulac

- sodium. There were also no minor incidents reported in aggregate incident reports.

Human Health Dietary

Food No Dikegulac sodium does not have any agricultural or food production uses, as such it is designated and

classified as a “non

- food” use chemical. Based on the low hazard concern from the available studies, no endpoints of toxicological concern have been identified. Due to the hazard profile drinking water assessments are not needed. In addition, because dikegulac sodium is not used on any agricultural food and/or feed

commodities and is classified as a “non

- food” use

chemical and metabolized to non

- toxic substances; a dietary risk assessment is not required. Drinking water No

Occupational Handlers (mixers, loaders, applicators) No While there are uses that could result in occupational handler and post

- application exposure, due to the (very) low systemic toxicity of dikegulac sodium, a quantitative occupational risk assessment is not warranted for any type, or duration of exposure. Post

- application No

Residential

Handlers No Dikegulac sodium is used in small quantities by the professional landscaping industry, and is not marketed

to homeowners. Residential post application exposure is possible from occupational application to residential use sites however, due to the (very) low systemic toxicity of dikegulac sodium, a residential quantitative risk assessment is not warranted for any type, or duration of exposure. Post

- application No

Other7

Aggregate No Evaluates the combined risk from dietary and residential exposures.

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 with dikegulac sodium. Dikegulac sodium does not appear to produce a toxic metabolite produced by other substances.

Tolerances No There are no tolerances to be assessed for dik egulac

sodium.

Incidents Will check for updates As of September 2014, there are no incident cases

reported for dikegulac sodium in either the Main or Aggregate Incident Data System (IDS) module, Poison Control Centers (PCCs), California Department of

Pest icide Regulation, National Pesticide Information Center (NPIC) and National Institute of Occupational Safety and Health’s Sentinel Event Notification System for Occupational Risks.

TIMELINE

EPA has created the following estimated timeline for the compl etion of the dikegulac sodium registration review in Table 3 below

. The projected timeline has not changed since the PWP.

Table 5: Projected dikegulac sodium Registration Review Timeline

Activities Estimated Date Opening the Docket Open Docket and 60

- day Public Comment Period December 2014

Close Public Comment February 2015 Case Development

Final Work Plan June 2015

Issue DCI July

- September 2015

Data Submission July

- September 2016

60

- day Public Comment Period for Draft Risk

Assessments 3 January

- March 2017

Registration Review Decision

60

- day Public Comment Period for Proposed Registration Review Decision June

- September 2017

Registration Review Decision and Begin Post

- Decision

Follow

- up January

- March 2018

Total (years) 4 years

3 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 pesticide s, the Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments.8

NEXT STEPS

As noted previously, the Agency plans to requ ire several ecolo gical effects studies for dikegulac

sodium through a D ata C all

- I n Notice , expected to be issued in late 2015

.