Docket Number EPA-HQ-OPP-2014-0180 www.regulations.gov



# MCPA Final Work Plan Registration Review

Case Number 0017
September 2013

Approved by:

### ~,::n

Date: Richard P. Keigwin, Jr. Director Pesticide Re

-evaluation Division 

# q-**c:J- '-f** INTRODUCTION This is the Environmental Protection Agency ' s (EPA or the Agency) Final Work Plan ( FWP ) for th e regi st ration review of MCPA (2-methyl-4-chlorophenoxyacetic acid). Thi s work plan addresses public comments received concerning the Prelimin ary Work Plan (PWP), which was posted in the MCPA r egistratio n review docket (EPA-HQ-OPP-20 14- 0 180). MCPA is a postemergenc e herbicide that i s registered for u se for selective control ofbroadleafweeds in various agricultural and non-agricultural settings. Agricultural use si t es include barley , flax, grasses grown for seed, oats, pastureland, peas , rye , and wheat. Non-agricu ltur a l use si tes i nclude uncultivated fields, ornamental and residential lawns , and turf. The registration review case for MCPA includes MCPA acid (PC code 030501), MCPA sodium salt (PC code 030502) , MCPA dim ethy lamine salt (PC code 030516), MCPA isoctyl ester (PC code 030563 ) , and MCPA 2- ethylhexyl ester (PC code 030564). The Agency is implementing th e registration review program pursuant to Section 3(g) of the Federal In secticide, Fungicide, and Rodenticide Act (F I FRA), and will review each registered pesticide every 15 years to determine whether it continues to meet the F IFRA standard for registration. Changes in scie nce, public policy, and pesticide use practice s occur over time. The registration review program is intended to make sure that , as the abi li ty to assess risk evolves and as policies and practices cha n ge, all r egistered pesticides continue to meet the statutory standard. The public phase of registration re view begins when 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 was issued. Next is a summary of substantive comm en t s received durin g the public commen t period for the PWP concernin g anticipated data needs, expected risk assessments, or t he estimated timeline id entified in the PWP , an d a summary of the Agency's responses to those comments. Th i s sect ion is followed by r egistration review planned data needs , risk assessment s expected to be conducted , and the projected registration review time line for MCP A. Lastly, there is a discussion of next steps . UPDATES SINCE THE PWP WAS ISSUED The PWP listed the acute oral toxicit y to adult honeybee and acute oral toxicit y to larval honeybee studies as anticipated data needs. The MCP A Task Force Ill commented that previou s ly submitted honeybee data may meet the Agency 's need for adult acute oral toxicity honeybe e data. A review of the existing MCPA honeybee data suggests that add itional adult acute oral toxicity hon eybee data will not be needed for risk ass essment, therefore, the pollinator acute oral toxicity study is being removed as a data req uirement. Due to the Agency's new guidance for assess in g r isks to bees (see guidance document dated June 19 , 20 14 at http: // www2.e pa.go v / sites / pr oduct ion / files / 20 1 4-

06 / documents/po llina tor ri sk assessment guida nce 06 19 1 4.pdt), the Agency is also modifyin g its pollinator data requirement s for MCPA to include two additional pollinator

studies: • Chronic ora l toxicity to l arval honeybees 1 http :// www .epa.gov / oppsrrd I / registration _review / 2

### • Chronic oral toxicity to adult honeybees
Various phenoxy herbicides are known to contain dioxinlfuran impurities as a result of manufacturing processes. Previously submitted dioxin!furan data for MCPA did not indicate levels ofconcern. However, recent data on dioxin!furan impurities in MCPB products has prompted the Agency to modify its list ofdata requirements to include guideline 830.1700-- preliminary analysis in order to confirm the presence/level ofdioxin!furan impurities in MCPA products using the most up-to-date analytical methods. The PWP listed guideline 875.2100 dislodgeable foliar residue as an anticipated data need because according to Agency policy at the time, these data were required when margins of exposure (MOEs) were less than 4 timesthe level ofconcern (LOC). Since the issuance ofthe PWP, the Agency has updated this approach and isnowrequiring dislodgeable foliar residue data when the occupational post-application MOEs are less than 2 times the LOC. Therefore, the Agency is removing its requirement for guideline 875.2100--dislodgeable foliar residue data.

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

### During the 60-day public comment period on the MCPA Preliminary Work Plan, which opened on March 28,2014 and closed on May 27,2014, the Agency received five submissions from the public. Comments were submitted by the MCPA Task Force Three, the Center for Biological Diversity, the Central Valley Regional Water Quality Control Board (ofCa lifornia), the FIFRA Endangered Species Task Force (FESTF), and a private citizen. The MCPA Task Force Three's comments covered the erroneous classification ofone product under an incorrect PC code, the submission ofpollinator data for MCPA, EPA's information request on dioxins and furans, and technical corrections for information cited in the Agency's registration review documents. The Center for Biological Diversity's comments addressed the Agency's responsibilities under the Endangered Species Act (ESA). The Central Valley Regional Water Quality Control Board asked EPA to consider the cumulative risk ofadditive toxicities between MCPA and other phenoxy herbicides during registration review. FESTF commented that the technical registrants, Albaugh, Dow, and Nufarm, are FESTF members and are entitled to rely on FESTF data for endangered species assessment. A private citizen commented in favor ofbanning MCPA and similar pesticides due to their potential for bioaccumulation in fatty tissues and potential damage to human health f rom endocrine disruption. 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 ofenvironmentaljustice, water quality concerns, and trade irritants, but no comments or informationwere received on those issues. This section does not capture every comment made about the PWP nor all ofthe Agency's responses. Summarized below are public comments that resulted in changes to the anticipated registration review data needs, risk assessments, ortimeline, or are ofa broader regulatory nature. Public comments and EPA responses in their entirety are located in the docket, EPAHQ-OPP-20 14-0180, accessible at www.regulations.gov. Summarized public comments and Agency responses related to the anticipated ecological risk assessment ordata needs are in the


### 3EFED Response to Public Comments on: Preliminary Problem Formulation for Environmental Fate and Ecologi cal Risk, Endangered Species, and Drinking Water Assessments for MCPA, while comments relevant to the anticipated human health risk assessment or data needs are in the document, MCPA. Re spo nse to Comments Received Regarding Scoping Documen t in Support of Registration Review. Public comments and Agency responses related to use and usage and the genera l registration review program are in the MCPA: PRD Responses to Comments on Registration Re view Preliminaty Work Plan.

Comments submitted by MCPA Task Force Th re e in EPA-HQ-OPP-2014-0180 - 0022. 1. Comment: An acute oral honeybee toxicity study completed according to OECD guidelin e 213 was submitted to EPA (MRID 47666601) and was evaluated as scientifically sound but was classified supplemental because it did not meet guideline requirem en ts. A second honeybee acute to xici ty study (MRJD 45897007) evaluating the contact and oral LD5o of MCPA acid was conducted according to EPPO Standard PP 1 / 1 70(2) and subm itted to the Agency. Response : The re gistration review problem formulation originally requested two honeybee studies: an acute oral toxicity study (fo ll owing OECD guideline 213) and a larval toxicity study (following OECD guideline 237). A review of MRIDs 4 766660 1 and 45897007 sugges ts that additiona l adu l t acu t e ora l honeybee data will not be needed for risk assessment. The Agency's policy on pollinator protection h as recently been updated (see http ://www2 . e p a . gov/s i tes/ pr o du ct i on/f il es/20 14 -

06 / document s/poll in ator ri s k asses s ment guidance 06 1 9 14.pdl). Accordingly, the Agency is modifying its pollinator data requirements to include an additional adult chronic oral toxicity hon eybee study and a repeat-dose chronic larval honeybee toxicity study. Thus ,

the Agency is modifying its pollinator data requirements to the following: • Acute oral toxicity to l arval honeybees • Chronic oral toxicity to larval honeybees • Chronic oral toxici t y to adu lt honeybees 2. Comment: Technical phenoxy herbicide registrants have provided dioxin/furan data at different times for several decades in response to Agency requirements for data on impurities of potential toxicological concern in technical MCP A products. These results have demonstrated non-detectable or extremely low detections while the LOQs for many dioxins/furans have steadily declined with analytical advances. EPA should make specific requests to technical registrants for additional data at currently achievable LOQs. R esponse: The Task Force i s correct ; the Agency has access to MCPA-specific information on dioxin/furan impurities in MCPA products. However , recent data on dioxin/fu ran impuri ties in MCPB products has prompted the Agency to modify its li s t of data requirements to include guideline 830.1700 - prelim inar y analysis, in order to confirm the presence / level of diox inlfuran im pu ritie s in MCP A products using t h e most up-to-date analytical method s. 3. Comment: MCPA is registeredfor use on alfalfa, barley, clover, flax , oats , pasture and rangeland grass, peas, rye, triticale, wheat, g rass grown for seed, turf, lawns, golf courses, 4andrights-of-way. For all these uses, there are limited (f any re-entry activitiespost application. Active ingredient-specific turftransferable residue data existfor turf uses. Since MCP A applications to allcrops are mad e early in the growth cycle whenplant height is less than 6 inches andsurface areas of leaves are small, the results from the existing turf transferable residue evaluations that mimic these conditions should be applicable for evaluation of dislodgeable foliar residues (DFR). 

## If EPA still believes a DFR study is still necessary, Agency input will be needed with regard to appropriate sampling techniques since a leaf punch system typically usedwill not be applicable. Data from theAgricultural Reentry Task Force mayalsoprovide evidence that MCPA crops are not appropriate or wellsuitedto conduct DFR studies. Response: When the scoping document was published, theAgency's policy was to require DFR data when MOEs were less than 4 times the LOC (<400). Since then, the DFRdata requirement screen has been updated to require DFR data when the occupational postapplication MOEs are less than 2 times the LOC (<200). Due to this change, DFR data are no longer required for MCPA.

Comments submitted by the Center for Biological Diversity in EPA
-HQ-OPP-2014-0180- 0020. 4. 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 MCPA in accordance with the Endangered SpeciesAct (ESA). The CBD comments mention various aspects of the risk assessment process, including use of the best available data to develop endangeredspecies risk assessments, andevaluation of effects on endangeredand threatenedspecies andtheir designated critical habitat. C BD also expresses concern regarding the rigor of theAgency ' s preliminary determinations regarding the effects of MCPA on endangeredandthreatened (listed) species and their designated critical habitat.for the MCPA regi stration review. Response: EPA has reviewed the comments from CBD on the registration review docket opening for MCP A and plans to address many ofthe concerns raised by CBD as part ofthe implementation plan for assessing the risks ofpesticides to listed species based on the recommendations ofthe April 2013 National Academy ofSciences (NAS) report. EPA will address concerns specific to MCPA in connection with the development ofits final registration review decision for this pesticide. In November 2013, the EPA, along with the Services and the USDA, released a summary oftheirjoint Interim Approaches for assessing risks to endangered and threatened (listed) species from pesticides. The Interim Approaches were developedjointly by the agencies in response to the NAS recommendations and reflect a common approach to risk assessment shared by the agencies as a way ofaddressing scientific differences between the EPA and the Services. The NAS report outlines recommendations on specific scientific and technical issues related to the development ofpesticide risk assessments that EPA and the Services must conduct in connection with their obligations under the ESA and FIFRA. Thejoint Interim Approaches were released prior to a stakeholder workshop held on November 15, 2013. In addition, the EPA presented thejoint Interim Approaches at the


### 5December 2013 Pesticide Program Dialogue Committee ( PP DC) and State-FIFRA I ssues Research and Evaluation Group (SFIREG) meetings. T he age n cies also held a stakeholder wor k shop in Ap r il 20 1 4, a ll ow in g additional opportuniti e s for stakeholde r s to co mm en t o n t h e In t er i m Approaches. Ad d i t io nal workshops a r e pl a nne d t o enhance stake h ol d er involveme n t; t he next works h o p is schedu l ed for Octobe r 2 014. As part of a phase d , i terative process for deve l op i ng the Interim Approaches, the agenc i es will also co n s i der public comments on the Interim Approaches in connection with the development of upcoming registration rev i ew decisions. The details of the joint Interim Approaches are contained in the whi te pap er , Interim Approaches for National-Level Pesticide Endangered Species Act Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report, dated November 1, 20 1 3 . Given that the age n cies a r e cont i n ui ng to develo p a n d wo r k t oward imple m e n tation of th e In te rim A pp roaches to assess th e po te nt ial r i sks of pest ic i d es t o li sted spec i es a n d t he i r des i gnate d cri t ica l habitat, the ecological p r oblem fo rmul at i on support i ng t hi s Fi n a l Work

P l an fo r MCPA does not descri b e t h e specific ESA analysis, including effects dete r m i nations for specific listed species or designated critical habitat, to be conducted during registration review. In the ecological problem formulation document for MCPA , EPA described the screening- l eve l risk assessment to determine the potential effects of MCP A on a ll taxa of non-target wildlife and plants, which will assume that listed species and thei r designated critical habitats may be present in t he vicinity of the a p p l ication of MCP A. This screeningleve l assessment will allow EP A to focus its f u ture eva l ua t ions on the types o f spec i es where t h e p o t e nt ia l fo r effects ex i s t s o n ce the sc i en ti fic met ho ds b e in g deve l oped by t h e a ge n c i es hav e b e en fully vetted. While the agenc i es co n tinue to d evelop a commo n met h od for ESA analysis, the planned scree n ing

- level risk assessment for t he registration r eview of MC P A will desc r ibe the level of ESA ana l ysis completed for this particular regis t ration review case. Once the agenc i es have fully developed and implemented the scientific methods necessary to complete risk assessments for e n dangered and threatened (listed) species and their designa t ed critical habitats, these methods will be applied to subsequent analyses for MCPA as part of comple t ing this registratio n r eview . 6PLANNED DATA NEEDS
Table I below summarizes the planned data needs for MCPA based on the EFED Registration Review Problem Formulation for MCP A, the MCP A. Human Health RiskAssessmentScoping Document in Support of Registration Review, the MCP A. Response to Comments Received RegardingScopingDocument in Support of Registration Review, and the EFEDResponse to Public Comments on: PreliminaryProblem Formulation for EnvironmentalFate andEcological Risk , EndangeredSpecies, andDrinking WaterAssessment sfor MCPA. The table has been updated since the PWP to reflect changes to the data needs

.
Table 1: Planned Data Needs for the MCPA Registration Review
Estimated Guideline Study Title Timef rame Number-2 Test Material (Months from receipt ofDCI) 830

. 1700 Preliminary analysis MP 8 835.1410 Volatility-laboratory TEP 12 850

. 1730 Aquatic organisms bioavailability, TGAI 12 biomagnification, toxicity (fish)3 850

.2100 Avian oral toxicity (passerine) TGAI 12 850

.2300 Avian reproduction (mallard duck) TGAI 24 Environmental chemistry methods and associated 850.6100 independent laboratory validation (soil, water, and TEP 12 sediment) 860.1300 Nature ofthe residue in plants (peas) PAIRA 24 860

. 1500 Crop field trials (peas) TEP 24

Non- Larval honeybee chronic oral toxicity4 TGAl 12 guideline

Non- Adult honeybee chronic oral toxicity TGAI 12 guideline

Non- Larval honeybee acute toxicity 4'5 TGAI 12 guideline TGAI = techmcal grade act1ve mgred1ent; TEP = typ1cal end-use product; PAIRA = pure act1ve mgred1ent radiolabeled; MP = manufacturing use product

2 On June 27,2012, EPA announced certain revisions in harmonized guideline series 850

- Ecological Effects Tests

- including renumbering and other designations orchanges for some guideline studies. See "Final Test Guidelines; OCSPP 850 Series; Notice ofAvailability" 77 FR 38282, June 27, 2012. http:/ /www.regulations .gov /#!documentDetaiI;D=EPA-HQ-OPPT

-2009

-0 154-0028 3 The planned DCI will indicate that testing is to be done on MCPA 2-ethylhexyl ester

. 4 A repeat dose honeybee larval toxi city study may be sufficient to assess both acute and chronic toxicity to developing brood. 5 The planned DCl will indicate that this study should follow OECD guideline 237.
7RISK ASSESSMENTS FOR REGISTRATION REVIEW Dur in g re gistration review, the Agency will conduct a comp reh ensive ecological risk assessment , including an endangered species assessment , for all uses of MCP A. For human health, EPA will

conduct revised dietary , residential, and occupational risk assessment s during registration review. I f human health or ecological toxicological endpoints or points of departure are revised

based on the data that are required for registration review, they will be considered in the new assessme nts , as well as any c hanges to the standard operating procedures or default exposure

assumpt ions. Table 2 below summarizes the planned registra t ion review risk assessments based on the EFED Problem F ormulation and HED Scopi ng Document; the planned assessm e nts have not changed from what was i nclud ed in the PWP. 8Table 2: Planned Risk Assessments for the MCPA Registration Review Type ofRisk Assessment Conduct? Notes Ecoloeical and Environmental Fate Comprehensive ecological 

### y (species to be assessed include terrestrial and aquatic organisms), including endangered species Incidents Will check for For a discussion ofreported ecological incidents for updates MCPA, see the Problem Formulation. Human Health Dietary Food 

### y An updated drinking water assessment is planned. Drinking water 

### y Therefore, a revised dietary assessment may also be likely to incorporate revised drinking water estima tes. Residential Handlers 

### y Updated residential handler and post-applicat ion Post-application 

### y assessments are planned since the Agency has revised its standard opera ting procedure for resident ial pesticide exposure assessment since the last human health risk assessment in 2004

. Bystander 

### y Residential exposure resulting from off-site transport may occur as a result ofagricultural applications of MCPA. The Agency will evaluate the need for spray drift and volatilization risk assessment during registration review

. Occupational Handlers (mixers, loaders, 

### y An updated occupational assessment may be applicators) warranted to reflect any changes to Agency policy. Post-application 

### y Other Aggregate 

### y An updated aggregated assessment may be warranted to reflect any updates to the dietary and/orresidential assessments. Cumula tive N MCPA is a member ofthe alkylphenoxy herbicide class ofpesticides. Although the various phenoxy herbicides have similar structural components, the Agency has not made a determination that they have a common mode oftoxic action, and therefore a cumulative risk assessment is not planned for MCPA. Tolerances 

### y The Agency plans to revise the tolerance expression for MCPA to be compliant with current policies.



### 9Incidents Will check for For a discussion of reported human incidents for updates MCPA, see the Scoping Document and the MCPA (2- methyl-4-chlorophenoxyacetic acid): Tier I Review of Human Incidents. TIMELINE E PA has c r eated the following estima t ed timeline for the completion of the MPCA registration review in Table 3 below. The projected timeline has been updated to reflect completed actions. Table 3: Registration Review for MCPA- Projected Reg i stration Review Timeline Activities Estimated Date · O pe ni ng the Docket Open Docket and 60-day Publi c Comment Pe r iod March 20 14-completed Close Public Comment May 20 14-completed

Case Development Final Work Plan Septem b er 20 14-completed Issue DC I 20 14 Oct. - Dec. Data Submission 2016 Oct. - Dec. 60-day Public Comment Period for Draft Risk 2018 Apri l - June Assessments Registration Review Decision 60-day Public Comme n t Per i od for Proposed 20 1 9 Jan . - March Registration Review Decision Registration Review Decision and B eg in Post-Decision 2020 Fo ll ow - u p Total (years) 6 NEXT STEPS As noted previously , the Agency plans to require several environmental fate , ecological effects , and human health studies for MC P A through a Data Call -I n Notice , expected to be issued in late 2014. 10