Docket Number EPA-HQ-OPP-2014-0279 www.regulations.gov



# Imazapic Final Work Plan Registration Review

Case Number 7234

March 2015

Approved by:

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Date: Richard P

. Keigwin, Jr. Director Pesticide Re-evaluation DivisionINTRODUCTION
This is th e Environmental Protection Agency 's (E PA or the Agency) Final Work Plan (FWP) fo r the regi s tration review of imazapic and imazapic ammonium (imazapic). This work plan addresses public comments received concerning the Preliminary Work Plan (PWP) , which was posted in the im azapic registration review docket (EPA-HQ-OPP-2014-0279). lmazapic is a systemic herbicide belonging to the imidazolinine class of pesticide , which share a common mechanism of action that involves the inhibition of acetolactate synthase (ALS) enzyme, an enzyme found in plants. [mazapic is registered to control certain grasses and broadleaf weeds on peanuts, grass (pasture and rangeland) and a wide range of non-crop areas including utility rightof-ways , airports, turf, and recreational (non-residential) sites.
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 eve ry 15 years to determine whether it continues to meet the FIFRA standard for registration. Chan ges in science , public policy, and pesticide use practices occur over time. T he registration review program is intended to make sure that , as the ab ility to assess risk evolves and as polici es and practices change, all regi stered pesticides continue to meet the statutory standard. The public phase of registration review begins when the initial docket is opened for each case. In formation on this program is provided on the Agency's website. 1
The FWP begins with any updates since the PWP was issued. Next is a summary of substant iv e comments re ceived 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 section i s followed by registration review planned data needs , risk assessments expected to be conducted , and the projected registration review timeline for imazapic. Lastly, there is a discussion of next steps.
UPDATES SINCE THE PWP WAS ISSUED There are no additional updates on imazapic since the PWP.
SUMMARY OF COMMENTS AND AGENCY RESPONSES
During the 60-day public comment period on the lmazapic Preliminary Work Plan , which opened on September 24, 2014 and closed on Novembe r 23 , 2014, the Agency received two public comments. Comment s were submitted by the FrFRA Endangered Species Task Force (FESTF) and the Center fo r Biological Diversity (C BD ). The comments do not address the timeline or the data requirements described in the PWP , but do add ress the planned ecological ri sk assessments. In the PWP , EPA al so solicited comments o n the specific topics of environme ntal justice, water quality concerns, and trade irritants, but no comm ent s or information were received on those issues.
Summarized below are the public comments. The full comments in their enti rety are located in the docket, EPA -HQ-OPP -2014

- 0279.

1 http:/ / www .epa.gov/oppsrrd I / regi stratio n_review / 

### 2Comments submitted by FESTF in EPA-HQ
- OPP-2014-0279 -0 012.
I. Co mment: FESTF noted the availability of data to inform the Agency's e ndangered species assessment, and identified the FESTF memb ers entitled to rely on FESTF data. Response: The Agency thanks FESTF for its comment and will consider this information during the imazapic regi stration review.
Comments submitted by CBD in EPA-HQ-OPP-2014 -02 79-0013.
3. Comment: CBD's comments focus on E PA 's duty to consult with the U.S. Fish and Wildlife Service and th e National Marine Fisheries Service (the Services) on the regi stration review of imazapic in accordance with the Endangered Species Act (ESA). CBD's comments mention various aspects of the risk assessment process , including use of the best available data to develop endangered s pecies risk assessments, and evaluation of effects on endangered and threatened species and their designated critical habitat. Response : E PA has reviewed the comments from CBD on the registration review docket opening for imazapic and plans to address many of the concerns raised by CBD as part of the implementation plan for assess ing the risks of pesticides to li s ted species based on the recommendations of the April 2013 National Academy of Sciences (NAS) report. EPA will addre ss concerns specific to imazapic in connection with the devel opment of it s final registration review decision for this pesticide.
In November 2013, the EPA, along with the Services and the USDA, relea se d a summary of their joint Interim Approaches for assessing risks to end angered and threatened ( listed) species from pesticides . The Interim Approaches were developed 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 sc ientific differences between the EPA and the Services. The NAS re port 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 wo rkshop held on November 15, 2013. In addition, the EPA presented the joint In terim Approaches at the December 2013 P estic ide Program Dialogue Committee (PPDC) and State-FIFRA Issues Research and Evaluation Group (SFIREG) meetings. The agencies also held a stakeho lder workshop in Apri 12014 and October 2014, allow ing additional opportunities for stakeholders to comment on th e Interim Approaches. Additional workshops are planned to enhance stakeholder involvement; the next work shop is sche duled for April 2015

. As part of a ph ased, iterative process for developing the Interim Approaches, the agencies will a l so consider public comments on the Interim Approaches in connect ion with the development of upcoming registration review deci s ions. The details o f the joint Interim Approaches are contained in the white paper, Int erim Approaches for National-Level Pesticide Endangered Spec ies Act Assessments Based on the Recommendations of the National Acad emy of Sciences April 2013 Report, dated November I, 2013.

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### Given that the agencies are continuing to de v elop and work toward implementation of the Interim Approac he s to assess th e pote ntial ri s ks o f pesticides to listed spec ies and their designated critical habitat, the ecological problem formulati on supp orting this Final Work P lan for imazapic does not describe the specific ESA analys i s, including effects determinations for spe c ific listed species or designated critic al habitat , to be conducted during reg i stration rev iew. In the ecological problem fo rmul ation document for imazapic, EPA described the screening-level risk assessment to determine the p o tential effects of imazapic on all taxa of non-target wildlife and plants , which will assume that li sted species and their des i gnated critical habitats may be present in the vicinity of the application of imazapic. Thi s sc reenin g- level assessment will allow EPA to focus it s future evaluations o n the types of species where the potential for effects exists once the sc ientific methods being developed by the agencies have been fully vetted. While the agencies continue to develop a common method for ESA analysis, the planned screening-level ri s k assessment for the registration rev iew of imazapic will describe the level of ESA analysi s c o mplete d for this particular registration r e view case. Once th e agencies have fully dev e loped and implemented the sc i entific methods necessa ry to complete ri s k as sessments for endangered and threatened ( li ste d) species and their designated critical habitats, these methods wi ll be applied to subseque nt analyses for imazapic as part of completing thi s registration review.

4PLANNED DATA NEEDS
Table I below summarizes 

### the planned data need s for imazapic based on the Problem Formula tionfo r Ecological Risk and Environmental Fa te, Endangered Species, and Drinking Water Assessments/or lmazapic and its Ammonium Salt. The plann ed data needs have not changed from what was included in the PWP

. Table 1: Anticipated Data Needs for the Imazapic Registration Review Estimated Guideli ne S tud y Title2 Timef ram e Nu mber2 Test Material (Months from receipt ofDCI)
830.6317 Storage Stabi li ty (so il ) T GAI 12 835.4100 Aerobic Soil Metabolism 3 TGAI 24 835 .4200 Anaer ob ic Soi l Metabolism TGAI 24 835.4300 Aerobic Aquatic Metabolism TGA I 24 850.2100 Avian Acute Oral Toxicity Test 4 TGA I 12 Non- Honey Bee Adu lt Acute Oral Toxicity 5 T GA I 12 g uideline

Non- Honey Bee Adu lt Chronic Oral Toxicity 5 TGAI 12 guideline

Non- Hone y Bee Larvae Acute Oral Toxicity 5 TGAI 12 guideline

Non- H o ney Bee Larvae Chronic Or al Toxicity 5 TGA I 12 guideline

Non- Semi-Field T esting for Pollinators 5• 6 TE P 24 guideline

Non-**Measur ~**  of Residues in Poll e n and Nectar5 • 6 TEP 24 guid el in e 850.3040 Fie l d Testing for Pollinators 5• 6 TEP 24 850.4100 Seedling Emergence and Seedling Growth 7 TEP 12 850.4150 Vegetative Vigor TEP 12 Environmental Chemistry Methods and 850.6100 Associated Ind ependent L aboratory TGAl 12 Validation s for Soil and Wate r TGA J =technica l grade active in gredien t ; TEP =ty pic a l end-u se product ;

2 On J une 27, 2012, EPA announced certain revision s in harmonized guideline se ri es 850

- Eco logical Effects Tests

- including ren umbering and other designations or changes for some guideline stud ies. See " Final Test Guidelines; OCSPP 850 Series; Notice of Availability" 77 FR 38282, June 27, 20 12. http: // www.regulations.gov /# ! documentDetai I; D= EPA-H0-0PPT-2009-0154-0028 3 Need three additional soils

. 4 Conducted with a passerine species. 5 A protocol shou ld be submitted to the Agency for review prior to study initiation. 6 The need for this test may be waived pending the results of the requested lower tier pollinator tests. 7 Data is requested for tomato, oats and ryegrass. 5In addition to the data needs listed in Table l, the 

### Problem Formulation identified the utility of an additional study which could improve th e accuracy of risk estim a tion s for imazapic. Data on the toxicity of i mazapic 's degradates to aquatic va sc u lar p lan ts from aquatic photo lysis (Guideline 850.4400 , Aquatic Plant Toxicity Test Using Lemna spp.) would h e lp better c haracterize ri sk to this taxa. Currently the Agency plans to estimate th e toxicity of residues to aq uatic organism s utilizing the Total Toxi c Res idue s (TTR) approach which assumes degradates are equally toxic as the parent Registrants are encou raged to s ubmit th e relevant data within the d ata s ubmission timeframe identified 

### in the Projec t ed Registration Review Timeline (see Table 3).
RISK ASSESSMENTS FOR REGISTRATION REVIEW
Dur i ng registration rev i e w , the Agency will conduct a comprehensive ecological risk assessment, including an endan gered sp ec i es assessment , for a ll uses of imazapi c . EPA anticipates the need to conduct revised dietary, residential and occ upat io nal , and aggregate risk assessments during re gistration review. 

### If toxicological endp o int s o r points of departure are revised based on the data that are anti cipated to be required for regist rati on rev iew, they will be considered in the n ew assessments. In additio n , any c hanges to th e standa rd operating procedur es ( SO P s) or default exposure assumption s will a l so be reflected in the assessments for registration review

. Table 2 be low summarizes the planned registration review risk assessment s based on the EFED Problem Formulation and HED Scoping Document. The planned as sess m en ts have not changed from what was included in the PWP.



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### Table 2: Planned Risk Assessments for the Imazapic Registration Review Type of Risk Assessment Conduct? Notes Ecologfoal and Environmenta l Fate Comprehensive ecological 

### y EFED will conservatively characterize this risk by assessment, including utilizing a TTR approach. In thi s approach , a s ing l e endangered spec ies (incl udes exposure concentration is estim a ted for total residues t errestrial and aquat ic (i.e. parent imazapic and the five degradates ident ified organisms) in the aqueous photolysis study) and compared to a representative toxic ity endpoint fo r the parent (i.e. assumes equal toxicity of each degradate to parent im azap ic) Incidents Will check for For a discus sio n of r e ported eco lo g ic al incidents fo r updates im azapi c , see page 22 of t he EFED Problem Formulation document. 

### Human Health Dietary Foo d y Acute oral endpoints could not be identified , and as a resul t an acute dietary expo sure assessment will not be conducted. In the mo st recent risk assess ment done in 2013, chro n ic dietary exposures were not of concern to HED. Drinking water 

### y A revised dietary exposure analysis may be required to reflect the most recent di etary exposure mo de l s and potent i al revised estimated dri nking water concentrations. Occupational Handlers ( mi xers , loaders, y Occupational handler inhalation exp osure assessments applicators) need to b e performed for the scenarios that h ave not been previou s l y asses sed. Post-application 

### y The need for a quantitative occupational po s tapp li cation inha lat ion exp osure assessment will be considered during registration review. Residential Handlers y The residential handler assessment may n eed to be revi se d based on new res idential handler SOP 's and policy changes for body weights an d toxicolo g ic al endp oints. P ost

- application N Residential post-application asse ssme nts do not need to be performed as imazapic l abe l d irect ion s indicate the turf u se is spec i fic to spot treatmen t onl y. Other Aggregate 

### y A new aggregate ri sk assessment may be required during Registration Review to incorporate any revised dietary exposure analyses and/or resident ial exposure assessments.

7Cumulative N EPA has not made a common mechanism of toxicity finding for imazapic and any other substances. Tolerances 

### N No data is needed to sup p o rt current tolerances fo r im azapic. Th ere are no maximum residue limits (MRLs) in Canada o r M exico for imazapic. MRL definitions differ betwee n U.S. and Codex , and 

### will be eval uated during registration review. Incidents Will check for For a discussion of rep orte d human incidents for updates imazapic , see page l 0 of the Scoping Document and the lma zapic and lmazapic Ammonium: Tier I R eview of Human In cidents.
TIMELINE
EPA has created the following estimated timeline for the completion of the imazapic registrati on review 

### in Table 3 below. The projected timeline has not changed since the PWP.
Table 3: Registration Revi ew for Im azapic
- Projected Registration Review Timeline Activities Estimated Date Opening the Docket O pen Docket and 60-day Public Comment Period September 2014

- Compl eted Close Public Commen t Novemb er 2014

- Completed Case De velopment Final Work Plan March 20 15

- Completed I ssue D C I April

- June 2015 Data Submission April

- June 2017 60-day Publ ic Co mment Period for Draft Risk October

- December 2018 Assessments 8 R e gis tration Review Decision 60-day Public Comment Period for Proposed April

- J une 2019 Reg istration Review Deci s ion R eg i stration Revi ew Decision and Begin Po st-D ec is ion 2019 Follow-up Total (years) 

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NEXT STEPS
As no ted prev io usly , the Agency plans to require sev eral envi ronmenta l fate, ecological eff ects , and human health studies for imazapic through a D ata Call -I n Not ic e , exp ected to be issue d by June 2015.

8 The regu la ti o ns governi ng Reg istration Review generall y require th e Age n cy to provide a public comment period of at l eas t 30 ca l e ndar days for draft ri sk assessments; see 40 CFR Part J 55.53(c). For conventional pesticides , the Age ncy plans to provide a 60 cal endar day public comment pe riod generall y fo r draft risk assessments

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