Docket Number: EPA-HQ-OPP-2010-0453 www.regulations.gov

United States Chemical Safety March 2011

Environmental Protection and Pollution Prevention Agency (7510P)



# Terbuthylazine Final Work Plan Registration Review

March 2011Docket Number: EPA-HQ-OPP-2010-0453 www.regulations.gov



### TABLE OF CONTENTS

Terbuthylazine Registration Review Team .................................................................... 1

I. INTRODUCTION ..................................................................................................... 2

II. SUMMARY OF COMMENTS RECE IVED ON PRELIMINARY WORK

PLAN

.............................................................................................................................. .... 2

III. RISK ASSESSMENT AND DATA NEEDS ........................................................... 2

IV. TIMELINE ................................................................................................................ 7

V. GLOSSARY of TERMS & ABBREVIATIONS .................................................... 8Docket Number: EPA-HQ-OPP-2010-0453 www.regulations.gov

Terbuthylazine Registration Review Team

Human Health & Environmental Effects

Nathan Mottl Najm Shamim

Risk Management

Eliza Blair

Lance Wormell

Office of General Counsel Philip Ross

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I. INTRODUCTION

This is the Environmental Protection Agency’s (EPA or “the Agency”) Final Work Plan (FWP) for the registration review of terbuthylazine (Case 2645). The FWP includes the expected registration review time line. The work plan also addresses public comments received concerning the Preliminar y Work Plan in the Summary Document which was posted in the terbuthylazine re gistration review docket, and any other comments concerning the ini tial docket postings. The Summary Document provided information on what EPA knows about the pest icide and what additional risk analyses and data or information the Agency believes are needed to make a registration review

decision.

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 year s to determine whether it continues to meet the FIFRA standard for registration. Changes in science, public policy and pesticide use practices will occur over time. The registrati on review program is intended to make sure that, as the ability to assess risk evolve s and as policies and practices change, all registered pesticides continue to meet th at statutory standard . The public phase of registration review begins when the initial docket is opened for each case. Information on this program is provided at: http://www.epa.gov/oppsrrd1/ registration_review/

.

The Terbuthylazine Preliminary Work Plan was entered into the docket for this registration review on September 29, 2010. The 60-day comment period ended on November 29, 2010. The Preliminary Work Plan document is available on www.regulations.gov , docket number EPA-HQ-OPP-2010-0453.

II. SUMMARY OF COMMENTS RE CEIVED ON PRELIMINARY WORK

PLAN

The Agency received no comments from registrants or the public during the comment period. The anticipated data needs, work plan and timeline described in the Preliminary Work Plan remain as they were presented initially.

In the Preliminary Work Plan, the Agen cy solicited comments on three specific topics: environmental justice, water body impairment, and trade irritants. No comments or information were received during the co mment period concerning these issues. This document makes final the work plan for the terbuthylazine registra tion review process.

III. RISK ASSESSMEN T AND DATA NEEDS

Terbuthylazine (PC Code 080814), first regi stered as an herbicide in 1975, is now registered for use solely as a slimicide in industrial recirculating cooling water applications and ornament al fountains. There are f our registered products. A Reregistration Eligibility Decision (RED) fo r terbuthylazine was issued by EPA in 1995.

The RED can be located at http://www.epa.gov/pesticides/reregistration/status.htm

.

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Human Health Risk

The Agency has reviewed all the availa ble information on toxicology and human exposure regarding terbuthylazin e and does not anticipate that additional data will be needed for this registration review case. If the results from the environmental fate data (see below) indicate that terbuthylazine has the pote ntial to pass through wastewater treatment plants and into drinking water, the need for a drinking water assessment will be

revisited.

Further information is available in “Summary of Human Health Effects Data for the Terbuthylazine Registration Review Decision Document”, dated July 19, 2010.

Dietary and Drinking Water Assessment

The need for a drinking water exposur e assessment will be revisited upon submission and review of the environmental fate data the Agency anticipates requiring through Registration Review. These environmenta l fate data will be us ed to determine if terbuthylazine has the potential to pass th rough wastewater treatment facilities into drinking water or migrate into residential gr oundwater wells as a resu lt of its current use

patterns.

Occupational and Resi dential Assessment

An occupational and/or residential expos ure assessment is required for an active ingredient if (1) cert ain toxicological criteria are triggered and (2) there is potential exposure to handlers (mixers, loaders, applicators, etc.) during use.

Currently, application to recirculating cooling water systems and ornamental fountains is required by the label to be clos ed-system only. In the event that the product needs to be handled, personal protective equipm ent is required by the label in the form of a long-sleeved shirt, long pants, shoes, socks, chemical-resistant gloves, and the availability of a chemical-resistant apron fo r spills. As a result, the Agency does not anticipate the need to conduct occupational and residential ha ndler dermal and inhalation risk assessments since exposure is minimized by the required engineer ing controls as well as the required personal protectiv e equipment. At this time, the Agency anticipates that no additional exposure data will be n eeded for this registration review.

Tolerances

There are no current tolerances or exemptions from tolerances for the active ingredient terbuthylazine, a nd no registered food uses.

Aggregate/Cumulative Exposure & Risk

In examining aggregate exposure, EP A takes into account the available and reliable information concerning exposures to pesticide residues in food and drinking

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water, as well as non-occupationa l pesticide exposures. Base d on current use patterns, an aggregate risk assessment will not be needed for terbuthylazine. Residential exposure is not expected and the need for a drinking water exposure assessment will be determined upon submission and review of the environmen tal fate data the Agency anticipates requiring.

Section 40(b)(2)(D)(v) of FFDCA require s that, when considering whether to establish, modify, or revoke a tolerance, th e Agency considers “available information” concerning the cumulative effects of a part icular pesticide’s residues and “other

substances that have a common mechanism of toxicity.” EPA has not yet determined whether terbuthylazine has a common m echanism with other compounds; however, during the risk assessment stage for regist ration review, the Agency will address the possibility that terbuthylazi ne shares a common mechanis m of toxicity with other

members of the Triazine Common Mechanis m Group (CMG) and whether terbuthylazine should be included in a cumulative exposur e group with the t hose triazines.

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EP A has not yet examined terbuthylazine for a possible common mechanism of toxicity with other chemicals. Terbuthylazine is a member of a class of pesticid es collectively referred to as “triazine” pesticides, and is structurally similar to some of them. The Ag ency has examined the some members of the triazine class of pesticides w ith respect to a potential common mechanism of toxicity; this examination may be found at http://www.epa.gov/oppsrrd1/REDs /triazine_cumulative_risk.pdf . Several members of

this class have been identifie d as causing toxicity through a similar mechanism of action; specifically, they disrupt endoc rine hormone production and have been shown to cause mammary gland tumors in rats.

For information regarding EPA’s efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by EPA’ s Office of Pesticide Programs concerning common mechanism determinations and procedures for cumulating effects from

substances found to have a common mechanism on EPA’s website at http://www.epa.gov/pesticides/cumulative/.

Because a data call-in program already ex ists to specifically address endocrine concerns (“Endocrine Disruptor Screening Pr ogram”, described below) the Agency does not anticipate that it will ask for endocrine-related data at th is time. However, if studies are received in response to an Endocrine Disr uptor Screening Program data call-in, such data will be considered as part of a future risk assessment.

Anticipated Human Health Data Needs:

All human toxicology and exposure data requirements have been fulfilled for the active ingredient terbuthylazine. The Agen cy has reviewed the available data for

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terbuthylazine and expects that no additional toxicity or exposure data will be needed for registration review.

Further information is available in “Summary of Human Health Effects Data for the Terbuthylazine Registration Review Decision Document”, dated July 19, 2010.

Anticipated Physical/ Chemic al Property Data Needs

All product chemistry data requirements have been fulfilled for the active ingredient terbuthylazine. Ther efore, the Agency does not an ticipate needing additional product chemistry data at this time.

Further information and detailed justificat ions for the studies that are anticipated as being needed are available in “Terbut hylazine: Product Chemis try / Environmental Fate and Eco-Effects Scoping Document”, dated July 28, 2010 .

Environmental Fate and Ecotoxicity

No environmental fate and ecological risk assessments have been performed for terbuthylazine. The Agency has reviewed th e environmental fate and ecological hazard databases for terbuthylazine. Based on its review, EPA believes the following environmental fate and ecological hazard risk assessments are needed to ensure that the registration review case meets FIFRA standards:

• Environmental fate

• Ecological hazard

• Endangered species assessment

The Agency expects that it will need to conduct environmental fate and ecological risk assessments for slimicides that potent ially pass through waste water treatment plants (WWTPs) and may be discharged into te rrestrial and aquati c environments.

Endangered Species

The Agency has not conducted a risk assessment that supports a complete endangered species determination for terbut hylazine. The ecological risk assessment planned during registration review will a llow the Agency to determine whether terbuthylazine’s use has “no effect” or “may affect” federally listed threatened or endangered species (listed species) or their designated critical habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or

National Marine Fisheries Services (the Services), as appropriate.

On January 19, 2011, the Center for Biologi cal Diversity and the Pesticide Action

Network North America filed a lawsuit in th e United States District Court for the Northern District of California, against th e Environmental Protection Agency (EPA) for

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allegedly failing to undergo consultation with the United States Fish and Wildlife Service

and the National Marine Fisheries Service re garding the effects of over 350 pesticides, including terbuthylazin e, on over 200 endangered and th reatened species throughout the United States (Center for Biological Dive rsity, et al. v. EPA, et al., No. C 11-00293 (N.D.Cal.).

Anticipated Environmental Fate and Ecological Data Needs

The Agency anticipates needing the followi ng data in order to conduct a complete environmental fate and ecotoxicity asse ssment, including an endangered species

assessment for all uses:

Environmental Fate Risk Assessment Data Needs :

o (GLN 835.3110) Ready Biodegradability

o (GLN 835.1110) Activated Sludge Isotherm

Ecological Risk Assessment Data Needs :

o (GLN 850.5400) Aquatic plant growth (algal), Tier II

Further information and detailed justificat ions for the studies that are anticipated as being needed are available in “Terbut hylazine: Product Chemis try / Environmental Fate and Eco-Effects Scoping Document”, dated July 28, 2010 .

Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and chronic toxicit y, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endpoints which may be susceptible to endocrine influence

, including effects on endocrine target or gan histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductiv e loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effect s in different taxonomic groups. As part of its most recent registration decision

, EPA reviewed these data and selected the most sensitive endpoints for relevant risk asse ssment scenarios from the existing hazard database. However, as required by FFDCA s ection 408(p), terbuthyl azine is subject to the endocrine screening part of the Endocri ne Disruptor Screeni ng Program (EDSP).

EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingred ients) may have an effect in humans or wildlife similar to an effect produced by a “natur ally occurring estrogen, or othe r such endocrine effects as the Administrator may designate.” The ED SP employs a two-tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays

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to identify the potential of a chemical substa nce to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to inte ract with E, A, or T hormonal systems will proceed to the next stage of the EDSP wher e EPA will determine which, if any, of the Tier 2 tests are necessary based on the avai lable data. Tier 2 te sting is designed to identify any adverse endocrine-related eff ects caused by the substance, and establish a dose-response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency mu st screen all pesticide chemicals. Between October 2009 and February 2010, EPA issu ed test orders/data call-ins for the first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. terbuthylazine is not among the group of 58 pe sticide active ingredients on

the initial list to be screened under the EDSP. Accordingly, as part of registration review, EPA will issue future EDSP orders/data call-ins, requiring the submission of EDSP screening assays for terbuthylazine. For further inform ation on the status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/

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IV. TIMELINE

The Agency has created the following estimated timeline for the completion of the terbuthylazine registration review:

Activities Estimated Month/Year

Phase 1: Opening the docket
Open Public Comment Period for Terbuthyl azine Docket Completed September 2010

Close Public Comment Peri od Completed November 2010
Phase 2: Case Development

Develop Final Work Plan (FWP) Completed January 2011

Issue DCI March 2012

Data Submission March 2013
Open Public Comment Period for Prelim inary Risk Assessments September 2015

Close Public Comment Period December 2015

Phase 3: Registration Review Decision
Open Public Comment Period for Propos ed Reg. Review Decision March 2016

Close Public Comment Period June 2016 Final Decision and Begin Post-Decision Follow-up 2016 Total (years) 6

Next Steps:

A Data Call-In (DCI) will be developed regarding the data gaps listed under the

“Risk Assessment and Data Needs” section. Also, human health and ecological risk

assessments will be conducted for all uses.

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V. GLOSSARY of TERMS & ABBREVIATIONS

ai Active Ingredient AR Anticipated Residue ASTM American Society for Testing and Materials

AWPA American Wood Preserver’s Association

CFR Code of Federal Regulations cPAD Chronic Population Adjusted Dose

CSF Confidential Statement of Formula CSFII USDA Continuing Surveys for Food Intake by Individuals

DCI Data Call-In DEEM Dietary Exposure Evaluation Model DFR Dislodgeable Foliar Residue DNT Developmental Neurotoxicity DWLOC Drinking Water Level of Comparison

EC Emulsifiable Concentrate Formulation EDWC Estimated Drinking Water Concentration

EEC Estimated Environmental Concentration EPA Environmental Protection Agency

EUP End-Use Product FDA Food and Drug Administration FIFRA Federal Insecticide, Fungicide, and Rodenticide Act FFDCA Federal Food, Drug, and Cosmetic Act FQPA Food Quality Protection Act FOB Functional Observation Battery GENEEC Tier I Surface Water Computer Model

IR Index Reservoir

LC 50 Median Lethal Concentration. A statistically derived concentration of a substance that can be expected to cause death in 50% of test animals. It is usually expressed as the weight of substance per weight or volume of water, air or feed, e.g., mg/l, mg/kg or ppm.

LD 50 Median Lethal Dose. A statistically deri ved single dose that can be expected to

cause death in 50% of the test animals when administered by the route indicated (oral, dermal, inhalation). It is expressed as a weight of substance per unit weight of animal, e.g., mg/kg.

LOC Level of Concern

LOAEL Lowest Observed Adverse Effect Level μg/g Micrograms Per Gram μg/L Micrograms Per Liter mg/kg/day Milligram Per Kilogram Per Day mg/L Milligrams Per Liter MOE Margin of Exposure

MRID Master Record Identifi cation (number). EPA's system of recording and tracking

submitted studies. MUP Manufacturing-Use Product

NA Not Applicable NAWQA USGS National Ambient Water Quality Assessment NPDES National Pollutant Discharge Elimination System

NR Not Required

NOAEL No Observed Adverse Effect Level

OPP EPA Office of Pesticide Programs OPPTS EPA Office of Prevention, Pesticides and Toxic Substances PAD Population Adjusted Dose PAIRA Pure Active Ingredient Radiolabelled PCA Percent Crop Area

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9 PDP USDA Pesticide Data Program PHED Pesticide Handler's Exposure Data

PHI Preharvest Interval ppb Parts Per Billion

PPE Personal Protective Equipment

ppm Parts Per Million PRZM/EXAMS Tier II Surface Water Computer Model Q 1 * The Carcinogenic Potential of a Compound, Quantified by the EPA's Cancer

Risk Model RAC Raw Agriculture Commodity RASSB Risk Assessment and Science Support Branch RED Reregistration Eligibility Decision

REI Restricted Entry Interval

RfD Reference Dose RQ Risk Quotient SCI-GROW Tier I Ground Water Computer Model

SAP Science Advisory Panel SF Safety Factor

SLN Special Local Need (Registrati ons Under Section 24©) of FIFRA) TGAI Technical Grade Active Ingredient

TEP Typical End-Use Product USDA United States Department of Agriculture UF Uncertainty Factor

WPS Worker Protection Standard