Docket Number EPA-HQ-OPP-20 13-0360 

www.regulations.gov 

Abamectin Final Work Plan 

Registration Review 

Case Number 7430 

December 2013 

Approved by: ~"')(..'~ e v~~~;' h 

Richard P. Keigwin, Jr. 

Director 

Pesticide Re-evaluation Division 

Date: 

INTRODUCTION 

This is the Environmental Protection Agency's (EPA or the Agency) Final Work Plan (FWP) for 

the registration review of abamectin. This work plan addresses public comments received 

concerning the Preliminary Work Plan (PWP), which was posted in the abamectin registration 

review docket (EPA-HQ-OPP-2013-0360). Abamectin is an insecticide/miticide/nematicide in 

the avermectin chemical family of macrocylic lactones isolated from the soil organism 

Streptomyces avermitilis. It is registered for use on various agricultural and non-agricultural use 

sites. Agricultural use sites include various stone and pome fruits, citrus, tree nuts, herbs, 

cucurbits, fruiting and leafy vegetables, cotton, plums, onions, and beans. Non-agricultural use 

sites include poultry houses, forest trees, ornamental plants, lawns and turf, woody shrubs and 

vines, private and commercial domestic dwellings, recreational areas, commercial transportation 

facilities, food and feed processing plants, eating establishments, dairy cattle, and distribution 

facilities. 

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 practices 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 registration review begins when the initial docket is opened for each case. 

Information 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 the public comment period for the PWP concerning anticipated data 

needs, expected risk assessments, or the estimated time line identified in the PWP, and a 

summary of the Agency's responses to those comments. This section is followed by registration 

review planned data needs, risk assessments expected to be conducted, and the projected 

registration review timeline for abamectin. Lastly, there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

The Agency is requiring an additional guideline 850.1 350 aquatic invertebrate life cycle 

(saltwater) study for registration review. The Agency has revisited the existing mysid shrimp 

chronic toxicity test, MRID 40856306, and found that it does not give a valid endpoint for 

reproduction because of a solvent effect. 

The projected registration review timeline has been updated since the PWP to reflect impacts of 

recent Agency actions shortening the timeframe between FWP and DCI issuance and adding a 

quarter in between posting of PRAs and proposed decisions. 

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

During the 60-day public comment period on the Abamectin Preliminary Work Plan, which 

opened on June 26, 2013 and closed on August 26, 2013, the Agency received 8 submissions. 

1 http://www.epa.gov/oppsrrd 1/registration_review/ 

2 
Comments were submitted by the technical registrant, Syngenta Crop Protection, the University 

of Hawaii at Manoa, the Western Integrated Pest Management Center, the Northwest 

Horticultural Council, the Washington State Potato Commission, the Wisconsin Potato & 

Vegetable Growers Association, the Idaho Potato Commission, and the FIFRA Endangered 

Species Task Force (FESTF). Syngenta's comments addressed the planned ecological risk 

assessment, teclmical corrections to the Agency's problem formulation, and the planned 

Endangered Species Assessment. The University of Hawaii at Manoa, the Western Integrated 

Pest Management Center, the Northwest Horticultural Council, the Washington Sate Potato 

Commission, and the Idaho Potato Commission submitted additional use and usage information 

and information on typical application rates which the Agency requested in its Preliminary Work 

Plan. The Washington State Potato Commission, the Wisconsin Potato & Vegetable Growers 

Association, and the Idaho Potato Commission all expressed support of the continued 

registration of abamectin products and highlighted abamectin's importance to the potato industry 

in the north-west. FESTF commented that the technical registrants, Syngenta Crop Protection, 

Cheminova Inc., and Nufarm Limited are FESTF members and are entitled to rely on FESTF 

data for the planned Endangered Species Assessment. 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. 

This section does not capture every comment made about the PWP nor all of the Agency's 

responses. Summarized below are public comments that resulted in changes to the anticipated 

registration review data needs, risk assessments, or timeline, or are of a broader regulatory 

nature. Public comments and EPA responses in their entirety are located in the docket, EPAHQ-OPP-2013-0360. Summarized public comments and Agency responses related to the 

anticipated ecological risk assessment or data needs are in the EFED Response to Public 

Comments Submitted in Response to the Abamectin Registration Review Problem Formulation 

PWP while those relevant to use and usage or those that address the general registration review 

program for abamectin are in the Abamectin (PC Code 122804): PRD Response to Comments 

on Registration Review Preliminary Work Plan. There were no comments pertinent to the health 

effects seeping document on the planned human health risk assessments. 

Comments submitted by Syngenta Crop Protection in EPA-HQ-OPP-EPA-HQ-OPP-2013-

0360-0017. 

1. Comment: The NOAEC value for the mysid shrimp should be 0. 0035 #g a ilL rather than 

0. 00035 f-ig a ilL. 

Response: For MRlD 40856306, the stated NOAEC of 0.00035 )lg ai/L was based on 

reproduction when compared to the negative control; the NOAEC of 0.0035 )lg ai!L was 

based on survival. EPA has revisited this study and determined that the survival qata were 

acceptable, but the reproduction data were invalid because a solvent effect on reproduction 

was observed. Reproduction is the most sensitive endpoint for risk assessment and EPA is 

requiring another guideline 850.1350 aquatic invertebrate life cycle (saltwater) study for a 

valid NOAEC for reproduction. 

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PLANNED DATA NEEDS 

Table I below summarizes the planned data needs for abamectin based on the EFED 

Registration Review Problem Formulation for Abamectin and the Abamectin. Human Health 

Assessment Scoping document in Support of Registration Review. The table has been updated 

since the PWP to reflect the addition of guideline 850.1350 aquatic invertebrate life cycle 

(saltwater) to the data needs. 

Table 1: Anticipated Data Needs for the Abamectin Registration Review 

Estimated 

Guideline Study Title1 Timeframe 

Number2 Test (Months from Material receipt ofDCI) 

835.2240 Photodegradation in water TGAI 12 

835.2410 Photodegradation in soil TGAI 12 

835.4100 Aerobic soil metabolism TGAI 24 

835.4300 Aerobic aquatic metabolism TGAI 24 

835.4400 Anaerobic aquatic metabolism TGAI 24 

850.1300 Aquatic invertebrate life cycle (freshwater) TGAI 12 

850.1350 Aquatic invertebrate life cycle (saltwater) TGAI 12 

850.1400 Fish early-life stage (saltwater) TGAI 12 

850.2100 A vi an oral toxicity (passerine species) TGAI 12 

850.2300 Avian reproduction (bobwhite quail) TGAI 24 

850.3030 Honey bee toxicity of residues on foliage TEP 12 

850.3040 Field testing for pollinators TEP 24 

850.4100 Seedling emergence TEP 12 

850.4150 Vegetative vigor TEP 12 

850.6100 Analytical method in water and sediment3 TEP 12 

Special Acute honey bee larval feeding study TGAJ 12 study 

Special Acute oral honey bee adult toxicity TGAI 12 study 

Special Whole sediment: chronic invertebrates freshwater and TGAI 12 study marine4 

TGAI = techn1cal grade act1ve mgred1ent; TEP = typ1cal end-use product; 

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 some guideline studies. See "Final Test 

Guidelines; OCSPP 850 Series; Notice of Availability" 77 FR 38282, June 27, 2012. 

http://www .regulations.gov/#! documentDetaii;D=EP A-1-10-0PPT -2009-0 154-0028 

3 Independent laboratory validations are needed for submitted environmental chemistry methods in water and 

sediment. 4 Please refer to draft guidelines 850.1760 (Chironomus dilutus), 850.1770 (Hyale/la azteca), and 850. 1780 

(Leptocheirus plumulosus) for guidance pertaining to this anticipated data need. 

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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 abamectin. For human health, EPA 

will conduct a revised dietary, occupational, and aggregate risk assessments during registration 

review. If toxicological endpoints or points of departure are revised for registration review, they 

will be considered in the new assessments, as well as any changes to the standard operating 

procedures or default exposure assumptions. 

The Agency will also revise the abarnectin labels for consistency with respect to the restricted 

entry interval for grapes, environmental hazards language, use directions for fire ant 

bait/granules, and other application parameters as part of registration review. 

Table 2 below summarizes the registration review risk assessments that will be conducted based 

on the EFED Problem Formulation and HED Scoping Document. 

Table 2: Anticipated Risk Assessments for the Abamectin Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecological and Environmental Fate 

Comprehensive ecological y 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

endangered species 

Incidents y For a discussion of reported ecological incidents for 

abamectin, see page 12 of the Problem Formulation. 

The Agency will check for updates if new incidents 

occur. 

Human Health 

Dietary 

Food N Acute and chronic dietary exposure estimates for food 

Drinking water y and drinking water from the 2012 risk assessment 

were below the Agency's level of concern. Revised 

drinking water exposure estimates may be required 

with current modeling methods; estimates are not 

expected to change substantially or to result in dietary 

risks of concern. 

Occupational 

Handlers (mixers, loaders, y The most recent occupational assessments were 

applicators) protective of previously unassessed scenarios. An upPost -application y to-date quantitative occupational risk assessment may 

be required to account for any changes in application 

rates, unit exposures, transfer coefficients, endpoints, 

and safety factors. 

Residential 

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Handlers N There are no registered products that would lead to 

any residential handler risks. 

Post-application N Residential post-application exposure to adults and 

children are unlikely for all registered uses of 

abamectin. 

Other 

Aggregate y Evaluates the combined risk from dietary and 

residential exposures. The 2012 risk assessment did 

not identify exposure estimates of concern. A new 

aggregate risk assessment is not anticipated unless 

toxicological endpoints/points of departure are 

' revised, the drinking water exposure estimates change 

substantially, or the Agency develops new 

policies/procedures to calculate residential postapplication inhalation exposure. 

Cumulative N Abamectin has not been identified as a member of a 

cumulative group that shares a common mechanism 

of toxicity. 

Tolerances N Tolerances were revised for several commodities in 

March 2013. No additional tolerance revisions are 

anticipated for registration review. 

Incidents Will check for For a discussion of reported human incidents for 

updates abamectin, see page 9 of the Scoping Document and 

the Abamectin: Review of Human Incidents. 

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TIMELINE 

EPA has created the following estimated timeline for the completion of the abamectin 

registration review in Table 3 below. The projected timeline has been updated since the PWP to 

reflect impacts of recent Agency actions shortening the timeframe between FWP and DCI 

issuance and adding a quarter in between posting of PRAs and proposed decisions. 

Table 3: Registration Review for Abamectin- Projected Registration Review Timeline 

Activities Estimated Date 

Opening the Docket 

Open Docket and 60-day Public Comment Period June 20 I 3 -Completed 

Close Public Comment August 20 I 3 -

Completed 

Case Development 

Final Work Plan December 2013 -

Completed 

Issue DCI 20 14 January -- March 

Data Submission 20 16 January -- March 

60-day Public Comment Period for Draft Risk Assessments) 2017 July- September 

Registration Review Decision 

60-day Public Comment Period for Proposed Registration Review 20 18 January -- March 

Decision 

Registration Review Decision and Begin Post-Decision Follow-up 2019 

Total (years) 6 

NEXT STEPS 

As noted previously, the Agency plans to require several environmental fate, ecological effects, 

and human health studies for abamectin through a Data Call-In Notice, expected to be issued in 

early 2014. 

5 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 generally for draft risk assessments. 

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