UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C.,20460 

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MEMORANDUM
Subject: RegistrationReview -Preliminary Problem Formulation for the Ecologic Assessment of Clethodim To: Susan Lewis, Chief ReregistrationBranch 1 SpecialReview and Reregistration Division Office of PesticidePrograms From: Ron Dean, Biologist JonathanAngier, Environmental S EnvironmentalRisk Branch 2 Environmental Fate and Effects Division 

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- Office of Pesticide Programs 

# i Through: Tom Bailey, Branch Chief Environmental Risk Branch 2 Environmental Fate and EffectsDivision Office of PesticidePrograms 

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Attached is the preliminaryproblem formulation for the ecological risk assessment to be conducted as part of the registrationreview ofthe herbicide clethodim.

## ECOLOGICAL RISK ASSESSMENT 

## PROBLEM FORMULATION FOR:

Ron Dean, Biologist Jonathan Angier, Environmental Scientist Environmental Risk Branch 2 Environmental Fate and Effects Division Office of Pesticide Programs

Tom Bailey, Chief Environmental Risk Branch2 Environmental Fate and Effects Division Office of Pesticide Programs

### STRESSOR SOURCE AND 

### DISTRIBUTION



## ............................................................................ INTEGRATION OF 

### AVAILABLE INFORMATION



## ................................................................... ECOLOGICAL EFFECTS



## ........................................................................................................ Toxicity Studies



## .................................................................................................... EXPOSURE CHARACTERISTICS



## ...........................................................................................

............................................. CHARACTERISTICS OF 

### ECOSYSTEMS POTENTIALLY AT 

### RISK CONCEPTUAL MODEL



## ........................................................................................................



## ................................................................................................. ANALYSIS PLAN OPTIONS ANTICIPATED DATA NEEDS



## ........................................................................................... LITERATURE CITED



## ............................................................................................................ 4 4 

### 5 

### 1



## ......... 5 

### 8 9 12 14 

### 15 

### 23

## STRESSOR SOURCE AND 

## DISTRIBUTION Clethodimis currentlyregistered for use as a post-emergence selective herbicide against a wide range of annual and perennial grasses (monocotyledon plant species)in a variety ofbroad leaf crops including soybeans, cotton, flax,peanuts, sunflowers, s gar beets, potatoes, alfalfa and vegetables. It is a member of the cyclohexenone or 

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cyclohexanedione class ofherbicides. The mode of action for this herbicide is lipi biosynthesis inhibition. Sensitivityor selectivityof grasses has been demonstrate to be due to a greater susceptibilityat the acetyl-CoA carboxylase (ACCase) enzyme of ass species. These grass species are killed by the inhibitionof the ACCase enzyme, w ich is a key enzyme in the lipid biosyntheticpathway. Clethodimis typically applied as irrigation systems). 

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spray, aerial spray, as spot treatment by hand spray, or by chemigation (via sprinkl r

I



### The most recent risk assessments available in the docket which serve as the basis f r this problem formulation include the following: 

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Use on Field Corn completed on October 1,2007 (DP Barcode: 333334) 

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Use on Asparagus, Herbs, Hops, Leafy Greens, Safflower,Sesame, and Su Beans and Peas completed on January 31,2007 (DP 

### Barcode: 3 13467) The ecologicalrisk assessment for the use on field corn found that clethodim pose risks above the Agency's Level of Concern (LOC) of 1.0to listed and non-listed monoc t terrestial plant species inhabiting semiaquatic areas that receive drainage fiom us sites (RQ = 

### 3.13). Clethodim does not exceed the Agency's LOC for direct toxic effect to birds, mammals, freshwaterinvertebrates, freshwater fish, aquatic dicot plants, or lgae for this use. No data were availableto evaluate potential risks to estuarinelrnarine

acute estuarinelmarine invertebrate data by which to perform th~s analysis. 

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organisms or to assess chronic risks to freshwater fish. Approaches for extrapolati g chronic toxicity values fiom existing data were exploredbut none were found to b appropriate. An 

### acute to chronic ratio cannotbe employed to estimatethese values due to the fact that there are no chronic aquatic invertebratedata, acute estuarinelmarine sh or 

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~ Based on the ecological risk assessment for uses on flax, 

### leafy greens, sesame, safflower, herbs, hops, asparagus, and legumes, clethodimwas predicted to pose risks above Agency's LOC to listed and non-listedmonocot terrestrial plant species inhabiting pland areas adjacentto clethodim use sites as well as semiaquatic areas that receive drain ge from clethodim use sites. Risk quotients which exceed the Agency's LOC 

### for mon cot species were 2.3 1 for non-listed and 3.8 

### for listed species inhabiting upland areas

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adjacentto clethodim applications,and 16.67 for non listed and 26.25 for listed spe semi aquatic areas exposed to clethodim runoff. Clethodim was not found to

### Toxicity Studies Agency's LOC for birds, mammals, fieshwaterinvertebrates, freshwater fish, aqutic plants, and algae for these uses. However, no data were available to evaluatepotebtial risks to estuarinelrnarine organisms or to assess chronic risks to fieshwater fish. 

# ! Approaches for extrapolatingchronic toxicity values from existing data were not 1



### Acute and chronic toxicity data from studies submittedby pesticide registrants the available open literature are used to evaluate the potential direct er'fects of to the aquatic and terrestrial receptors identified in this section.This includes data on the technical grade active ingredient, degradates, and when available, products (e.g. "Six-Pack" studies).' 

### The open literature studies are identified EPA7s ECOTOX database (http://c~ub.eva.aov/ecotox/), 

### which employs a litera search engine for locatingchemical toxicity data for aquatic life, terrestrial wildlife. The evaluation ofboth sources of data can also provide insight and indirect effects of clethodim on biotic communities fiom loss of sensitiveto the chemical and 

### from changes in 

### structure and the affected communities. appropriate due to lack of chronic aquatic invertebrate, acute estuarinelmarinefish acute estuarinelmarine invertebrate data.

Clethodirn and its metabolites containing the 

### 5-(2-ethylthiopropyl)cyclohexene-3-dne and 

### 5-(2-ethylthiopropy1)-5-hydroxycyclohexene-3-one moieties and their sulfoxides sulfones are all expressed as clethodim and will be modeled as total residues. Tab e 1 

### provides a summary ofthe taxonomic groups and the surrogate species tested to h lp understand potential acute ecological effects of pesticides to these non-targettaxo omic groups. In addition, this table provides a preliminary overview ofthe potential ac e toxicity of clethodimby providing the acute toxicity classifications. 

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i 

### andTable 1. Test SpeciesEvaluated for Assessing Potential Ecological Effects of Clethodim and AssociatedAcute Animal Toxicity Classification

Taxonomic Group 

## ( Example(s) of Surrogate Species 

# I Acute Toxicity CIassification I I

Bobwhite Quail (Colinus virginianus) PracticallyNon-Toxic MRID 409745-26 Bobwhite Quail (Colinus virginianus) MRID 409745-25 PracticallyNon-Toxic

Mammals the

Insects Laboratory rat (Rattus novvegicus) MRID 409745-07 Slightly Toxic Honey bee (Apis rnellifea) MRID 410302-05

Freshwater fish2

~reshwiter fish may be surrogatesfor aiuatic-ph&e amphibians.&PracticallyNon-Toxic

Freshwater invertebrates



### Monocot plants are of special concern due to the fact that clethodim is an mode of action specificto them. Clethodim is slightly toxic to moderately toxic to 

### freshwater invertebrates. There are no data to evaluate acute chronic effects to estuarinelmarinefish and estuarinelmarine endpoint values are summarized in Table 2. Assessment endpoints for Clethodi Rainbow trout (Oncorhynchus mykiss) MRID 409745-28



### I 1. Abundance (i.e., ( la. Acute 

### I Bobwhitequail 

### I Single oral 

### 1 >2000 ( 409745-25 

## I slightly ~~~i~

Birds represent surrogates for terrestrial-phase amvhibians and reutiles. Water flea (Daphnia magna) MRID 416851-01

survival, reproduction, and (Dose growth) of individual birds based) Moderately Toxic

2. Abundance (i.e., survival, reproduction, and growth) of individual mammal (Dietarybased)

Chronic(Dietarybased)

Chronic



# r (Colinus dose virginianus)
(Colinus virginianus) Bobwhite quail Avian 250 ppm 410302-06 

### * (Colinus reproduction (NOAEC) (Supple iental) virginianus) study I I I I Rat (Rattus 

### I Single oral ( 1,360mg ( 409745-47 nomegicus) dose I Rat (Rattus 2-Generation 500ppm a.i norvegicus) reproduction (NOAEC)reproductionof iYeshwater fish and invertebrates

populations of non-target terrestrial plants (crops and non-crop plant(Selenastmm capricomutum) Freshwater diatom (Navicula pelliculosa) - 

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(NOAEC) 6d. Algae

adequately explained. 

## I

Incident Reports Marine alga (Skeletonema costatum) 

## I I (NOAEC) 

## I

Incident # 

### 1002969-058 

### In 1995 the use of Select 2EC 

### (a.i. Clethodim) allegedly caused damage to after direct application in Florida. The certainty that clethodimcaused this was 

### "possible"; however the legality ofthis applicatiofiis 

### undetermined. only incidentreported involving clethodim.

Important physical/chemical properties of clethodim are listed in Table 

### 3. 120 hours



### * The study is classified as supplemental because it was determined to be scientificallysound but does not fulfill requirements for an avianreproductive test, since a high rate of adult mortality in both control and test subjects



### Table 3 

### Nature of 

### the Chemical Stressor I i the

was not 8.6mg a.i./L (EC,) 5.4 mg a.i./L



### Persistence: With a soil aerobic half-life of 

### <3 days and an aerobic aquaticha1 -life of 

### 5 days, clethodim is fairly non-persistent under aerobic conditions. However, t is 

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much more persistent in anaerobic conditions; half-life in anaerobic waterlsedipent Common name Chemical name
Pesticide type Chemical class CAS number Empirical formula Molecular mass (glmol) Vapor pressure Henry's Law Constant (atm-m3/mol) Solubilityin water (mg/L) pKa 420297 Accept

Clethohm (E,E)-(~)-2-[1-[[(3-chloro-2-propenyl)oxy]imino]propyl]-5-[~2- (ethy1thio)propyll-3-hydroxy-2-cyclohexen- 1 -one herbicide cyclohexenoneor cyclohexanedione 99129-21-2 c17H26c1N03s 359.9 4.2mPa at 20 OC 1.2~1 0-l1 atm-m3/mol 5400 at pH 7 (solubility is highly pH dependent) 4.47 04 'ble

Log Kow 4.2

### systems was 177days (at 25OC). Two toxic degradates of concern, clethodim I 

### sulfoxide and clethodim sulfone, are much more persistent than parent, with s aerobic half-lives of -35 days. Both parent clethodim and degradates of conc (sulfoxide & 

### sulfone) are mobile, with Koc 

### values ranging from 5-270 ml/g Mobile" to "Moderately Mobile" according to FA0 classification scheme). 1 

### The major degradationpathway for clethodim is microbial in additionto phot Clethodim is essentially stableto hydrolysis and photolysis is dependant upon exposureto direct sunlight (although photolysis may be a significant mechanism for foliar applicationsinbright sunlight, as occurs too rapidly to establish a half-life). Aqueous ranged fi-om 1.4days (at pH 5) to 9.3 

### days (at 

### pH 9) 

### pH 7 were approximately4-6 days. The main routes of dissipation in the environment are likely to be microbial degradation, leaching and runoff. Volatilization is not expected to be an imp0 ant dissipationpathway. 

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The major degradatesof clethodim that qualify as degradates of concern are clethodim sulfoxide and clethodim sulfone (Federal Register / 

### Vol. 62, No. 29 February 12, 1997). Both ofthese toxic degradates are more mobile and persi tent than the parent, so are more likely to present risk in aquatic and terrestrial environments. 

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### No surface water monitoring data for clethodim or its major degradates were the literature or the U.S. Geological SurveyNAWQA database. Clean 

### Water Act: 

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Clethodimis not identified as a cause of impairment for any water bodies listed as

# ~ impaired under section 303(d) of the Clean Water Act, based on informationpro~ired 

### at: http://oaspub.epa.gov/Wwaters~~ist.impaiments?pimpid=3. The Agency invi es 

# X submission of water quality data for this pesticide. To the extent possible, data sh uld conform to the quality standards in Appendix A ofthe OPP Standard Operating 

# ~ Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in O~P'S 

### Registration Review Risk Assessment and Management Process (see: 

### ht.tp://www.epa.gov/oppfeadl/cb/ppdc/2006/novemberO6/sessionl -sop.pdf), in ensure they can be used quantitatively or qualitativelyin pesticiderisk

Clethodimis currentlyregistered for use on a variety of crops. A map of the US is represented in Figure 1. This map is based on 2002 data and is map available. New uses on Asparagus, Corn, Herbs, Hops, Leafy Sesame, SucculentBeans and Peas have been registered since this

### In 2008, estimated annual agricultural use was roughly 424,500 pounds of applied in the United States. The majority is applied to Soybeans Beets (80,000 lbs), Sunflowers (40,000 lbs), Alfalfa (30,000), and (20,000 lbs each). Screeninglevel estimates of agricultural uses of clethodim are 

# ~ described in Table 4. 

## 1 Figure 

### 1. 2002 EstimatedAnnual AgriculturalUse 

### Map for clethodim (Sourc USGS).

CLETHODIM

### - herbicide 2002estimated annualagriculhualuse

Average annual use of actve ingredient (pomdspersquare mileof aglcultural land incounty) - k.! noestimateduse o.oo1 to 0.008 0.- to 0.038 0.039 to 0.132 0.133 to 0.322 

### 1>=0.323 

# 1 miion alfalfa hav Total DoundsawM

### Screening Level Estimates of Agricultural Uses of Clethodirn January 28,2008 Screening Level Estimates ofAgricultura1 Uses of CLETHODIM 121011 Sorted Alphabetically Crop Alfalfa Almonds Apples Asparagus Barley+ Beans, Green Beets ( NPUD '02 ) Broccoli Brussels Sprouts

### * Cabbage CanolaIRapeseed Cantaloupes Carrots Celery Cherries Corn Cotton Cucumbers Dry Beandpeas Garlic Lettuce Mint (NPUD '02 ) Nectarines

### * + Olives 

### * Onions Oranges+ Peanuts Peas, Green peppers Pistachios

### * Potatoes Pumpkins Sod (NPUD '02 ) + Sorghum Soybeans Squash Strawbemes Sugar Beets Sunflowa Sweet Corn Sweet Potatoes ( NPUD '02 ) Tomatoes Walnuts Lbs. A.I.

All numbersrounded. '1500' indicates lessthan 500 pounds of active ingredient. '<2.5' indicates less than 2.5 percent of crop is treated. '4' indicates less than 1percent of crop is treated. 

### * CA data only, but 95% or more of U.S. acres are in California Percent CropTtd. Avg. Max.

<I <2.5 <1 <2.5 <1 c2.5

5 10 <1 <2.5 <I 5 N/C <1 10 10 N/C NIC <1 <2.5

5 5 <1 5 15 35 5 5 <1 <2.5 <1 <2.5 <I <2.5 <1 12.5

5 5 5 5 <1 <2.5 NIC 5 N/C N/C N/C N/C 15 30 <1 c2.5

10 10 <1 c2.5

5 10 NIC NIC <l 5 10 20 N/C <1 <1 (2.5

5 5 5 5 5 5 45 45 20 25 <1 <2.5 N/C <1 il 5 <1 12.5

SLUA data sources include: USDA-NASS (United StatesDepartment of Agriculture's National Agricultulal StatisticsService); 2001-2006 Private PesticideMarket Research, 2001-2006 NPUD 2002 (National PesticideUse Database) ofthe CropLife Anerica Foundation and California DPR data. These results reflect amalgamated data developedby the Agency and are releasable to the public. NIC =Not calculated + = These crops were not listed as activeproduct regismtiom when this report was run

### Assessment endpoints are defined as "explicit expressions ofthe actual environmjntal value that is to be protected." Defining an assessment endpoint involves two st identifying the valued attributes ofthe environment that are considered to be at 2) operationally definingthe assessment endpoint in terms of an ecological enti community of fish and aquatic invertebrates) and its attributes (i.e., survival and reproduction). Therefore, selection ofthe assessment endpoints is based on value entities (i.e., ecological receptors), the ecosystems potentially at risk, the migatio pathways ofpesticides, and the routes by which ecological receptors are expos pesticide-related contamination. The selection of clearly defined assessment important because they provide direction and boundaries in the risk assessment fo addressing risk management issues of concern. Changes to assessment endpoints typically estimated from the available toxicity studies, which are used as the effects to characterizepotential ecological risks associated with exposureto such as clethodim. To estimate exposure concentrations, the ecological risk assessment considers at the maximum rate to fields that have vulnerable soils. Ifmultiple applications allowed, the maximum amount per application and minimum intervalbetween applications are used -

### provided that maximumtotal annual application included in this configuration. Several EFED exposure models (e.g., EXAMS, T-REX) areused to estimate likely high-end exposureto sensitive toxicity endpoints are used from surrogate test species to related direct effects on acutemortality and chronic reproductive, assessmentendpoints. Toxicity tests are intended to determine exposure on birds, mammals, fish, 

### tests include short-term acute, sub-acute, and arranged in a hierarchical or tiered system applied field studies. The toxicity studies to cause adverse effects, to determine whether further testing is required, and to determine the need for precautionarylabel effects to non-target animals and plants.

In order for a chemical to pose an ecological risk, it must reach ecological pesticide moves in the environment from a sourceto an ecological receptor. For biologically significantconcentrations. An 

### exposure pathway is the means by ecological exposurepathway to be complete, it must have a source, a release an environmental transport medium, a point of exposure for ecological receptors, feasibleroute of exposure. The conceptualmodel (Figure 2) 

### depicts the potential pathways for ecological risk 

### associated with clethodim use. The conceptual model provides an overview ofthe

### expected exposureroutes for organisms within the clethodim action area. For tenestrial organisms, the major route of exposure (aside fiom direct contact to insects fiom applications) considered here is ingestion of food items such as grasses, other gee vegetation, seeds, and insects that harbor clethodim residues as 

### a result of direct 

# p application or drift. For aquatic organisms, the major routes of exposureare consi ered to be via the respiratory surface (gills) or the integument. Aquatic plants may be e posed via direct uptake and adsorption. Estimated exposure concentrations for all organi ms are obtained through the use of several Agency exposure models. Note that only aeriallground spray and chemigation applications are depicted here; hand spray (s ot treatment) is expectedto result in much less exposure. 

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Figure 2. 

### Ecological conceptual diagramfor clethodirn I

Stressor
Source1 Transport Direct Runoff1 Leaching Erosion drift (Infil:&tion/ Pathways 

## A A - Percolation I

Source/ Terrestrial Food Media Clethodim Applied by Ground SprayIAir Spray/Chemigationto Field

Exposure Route 

### 1

Receptors Upland and Surface Water 

# + ingestion 

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- ingestion

Birds, Mammals, Reptiles, Terrestrial Phase Amphibians 

# + contact

Beneficial

lnsects 

# I + contacuroot

uptake

L------ 

# t

Upland and 

# + gill/integument 

# +

uptake and co tactlroot

cot

## I Aquatic 

### lhp?ke

Vertebrates and

Invertebrates 

# L-r' T

Reduced growth emergence and Reduced survival Reduced growth

### Based on an examination of the physicavchemical properties of clethodim, the fatg and disposition in the environment, and mode of application, a conceptual model was developed that represents the possible relationships between the stressor, receptors, and the assessment endpoints. For clethodim, the following hypothesis is being employed for thisbaseline risk assessment: Clethodim,when used in accordance with the label, results in 

### potential adverse effectsupon the survival, growth, and reproduction ofnon-target monocot plants exposed to runoff and drift 

### from areas treated with clethodim. There are no data to assess the effects of clethodim exposure to passerine birds, estuarinelmarine organisms or the chronic risks that clethodim may pose to freshwater fish. Due to the fact that the sensitivity to chemicalsmay vary greatlybetween groupings oftqxa, and that the acute sensitivity of an organism may not accurately predict the chronic sensitivity,the Agency must make the assumptionthat there will be acute and chronic risks to species for which there are no data. Although clethodimis fairly non-persistent, it is mobile and is expected to occur in adjacent aquatic ecosystems on a continuous or recurrent basis. Also, the major toxic degradates of concern (clethodim sulfoxideand clethodim sulfone) are much more mobile and persistent than the parent. Thus, there is a possibility for exposure to terrestrial and aquatic organisms.

In registration review, pesticide ecological risk assessments will follow the Agenc Guidelines for Ecological Risk Assessment, will be in compliance with the paper "Overview ofthe Ecological Risk Assessment Process in the Office of Pesticide 

## 1 Programs, U.S. Environmental Protection Agency" ("Overview Document") (Januky 2004), and will be done in accordance with Section 7 

### of the Endangered Species~bt. Results from aquatic and terrestrial exposure models (GENEEC 2, Rex) will be used to determine likelyhigh-end exposure clethodim use (and compared with results from previous exposure model PRZM-EXAMS will likelybe used screeningmodel GENEEC 2 had been used in the most D333334 NU 

### on Corn; 10/1/2007). These predicted determine the possible environmental effects of clethodim use. If the planned ecological risk assessmentindicatesthat clethodim exceeds the Level of Concern for Listed species, either directly or Affect" determinationwill be made for the affected taxa (e.g., invertebrates, etc). A map of the clethodimuse 

### "footprint," types for which the LOC is exceeded will be generated, along with a narrative

### ofthe area outside the footprintwhere effects are expected to occur. These maps kd narrative descriptionswill be provided to the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (the Services) for them to determine which listdd species may be affected. The Agency will then consult with the Services,formal14 or informally,to refine the Effects Determination.
,



### The Agency does foresee requiring additional ecological effects studies prior to conductingthe planned assessments. Data gaps, uncertainties and potential paths for the assessment of clethodim are described below.

aquatic, forestry, and residential turfuse patterns when those uses can lead to exposure in estuarine andlor marine habitats. 40 

### CFR Part 158now requires acute toxicity data on one estuarinelmarinemollusk, one

or runoff is expectedto enter estuarine and marine ecosystems. 

# ~ I The requested data would allow EPA to estimate acute risks to estuarinelmarinemollusks, I invertebrates, and fish, including defining an action area for endangered species. Risk miti ation strategies (e.g., determiningthe maximum clethodimapplicationrate that results in an RQ elow the LOC) cannot be evaluated without these data. 

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IPractic 

### J Utility ofthe Data 

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How 

### will the data be used? These data are needed for a registration review decision and for an endangered species asshssment, which will be conducted as part ofthat decision. The data would allow the Agency to dete ne acute risk to estuarinelrnarineorganisms from water exposure to clethodim. The effects d a would be used to determinethe likelihood that the acute risks can potentially impact aquat'c communities, either by direct effects or by indirect effects on other organismsby reducing heir food sources. 

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~I How could the data impact the Agency9s future decision-making? Risk assessment and mitigation strategies (e.g., determiningthe maximum clethodim appl' ation rate that results in Risk Quotients (RQs) below the Level of Concern (LOC)) cannotbe ev luated without these data. If future endangered species risk assessments are performed without t se data, the Agency would have to assume that clethodim "may affect" endangered saltwater

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mollusks, fish, and invertebrates directly (and endangered species from other taxa use of clethodim might need to be restricted in areas where endangered species The lack ofthese data will limit the flexibility the Agency and registrants have compliancewith the Endangered SpeciesAct and could result in use restrictions for cletho which are unnecessarily severe.

Sincethe registration of clethodim,the Agency has worked to finalize its update to the da requirements in 40 CFR Part 158. These updated data requirements were promulgated in

# $ ctober 2007. Now one freshwater invertebrate life-cycle study is required to support all terrestridl use patterns. i The Agency had conditionally required fish early-lifestage and aquatic invertebrate life-c$cle studies (guidelines 850.1300, 850.1350, and 850.1400) for terrestrial food and nonfood, a uatic food and nonfood, forestry, and domestic outdoor uses. These studies still are not require for the applicabilityofthe requirements. 

# 4 greenhouse food andnonfood, and indoor uses. The Agency has made several revisions to1 clarify 

## I The first is to list the fish early-life stage and aquatic requirements in the data table; then identify each species. For the freshwater fish early-life stage and changed the conditional requirement for terrestrial and aquatic forestryuses to required, and changedthe aquatic nonfood Previously, the freshwater invertebrate life cycle and fish early life stage tests required for terrestrial, aquatic (food crop and 1984, one basis for the conditional nature of was required, depending on whether fish or However, when a pesticide enters the aquatic environment, both groups of organisms are exposed. Moreover, acute sensitivity is not when looking across different groups of results of acutetesting. The change to to the fact that the previous "aquaticoutdoor and aquatic nonfood residential. As the latterrepresents a much smalleruse patte&, the Agency has reduced or eliminated the datarequirement for aquaticnonfood residential uses. In addition, the Agency now requires both of these tests for all turf uses includingresidentlad, since exposure varies. I This change was warranted because the relative sensitivity of fish and invertebratescanv ry widely across chemicals.Previously, only the more sensitive ofthe two organisms, either ish or aquatic invertebrates, as determined by Tier 

### I acute studies, was tested. However, since b th organisms are exposed when a pesticide enters an aquatic environment and the acute sensi ivity of an invertebratemay not accurately predict the chronic sensitivity in fish and vice versa, b th

would suggest. Practical Utilify 

### of the Data How will the data be used? 

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species must now be tested for chronic effects. The Agency cannot make the assumption hat a chemical is not chronically toxic at much lower concentrations than some ratio ofthe LC5 value

The data will be used to estimate potentialrisks to freshwater aquatic invertebratesand to keduce uncertainties associatedwith the current ecologicalrisk assessment. ,
I How could the data impact the Agency's future decision-making? I 

### I Without these data, the Agency cannot determinethe levels of clethodimthat could result 

# i. adverse effects to freshwater aquatic invertebrates. The lack ofthese data will limit the flyxibility the Agency and registrants have in coming into compliance with the Endangered Species could result in use restrictions for clethodim which may otherwisebe avoided, or which are unnecessarily severe.

, 

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,,,, RationaleforRequiring the Data Since the registration of clethodim, the Agency has worked to finalize its update to the data requirements in 40 CFR Part 158. Theseupdated datarequirements were promulgated in 2007. Now one estuarinelmarineinvertebratelife-cycle study is required to support all aquatic, forestry, and residentialturf use patterns when those uses can lead to exposure in estuarine and/or marine habitats. Act, and 

## 4;Jj;$;$!?4it? "t:e&> ~~;~b~ra;~6~,j*hh;~,*b:~~*~+~~'

October terrestrial,

I 40 CFR Part 158 was revised to list the fish early-life stage and aquatic invertebrate studies as separaterequirements in the data table; then identify each test organism or saltwater species. For the saltwater fish early-life stage and saltwater invertebratelifedata requirements, the Agency requires testing of one fish species and one aquatic species, respectively, for the terrestrial, aquatic, forestry, and residentialturf use estuarine or marine habitats may be exposed to the chemical. Previously, the saltwater invertebrate life cycle and saltwater fish early life stage tests were combined requirement with testing required of only the more sensitive species in acute studies. Hovlewr, when a pesticide entersthe aquatic environment,both groups of organisms are exposed. Moreover, acute sensitivityis not a reliable indicator of chronic sensitivity, particularly wden looking across different groups of organisms, so chronic data are needed regardless ofthe results of acutetesting. I This change was warranted because the relative sensitivityof fish and invertebrates can vary widely across chemicals. Previously, only the more sensitive ofthe two organisms, either fish oraquatic invertebrates, as determined by Tier 

### I acute studies, was tested. However, sincebbth organisms are exposed when a pesticide enters an aquatic environment and the acute sensitivity of an invertebratemay not accuratelypredict the chronic sensitivityin fish and vice versa, bgth species must now be tested for chronic effects. The Agency cannot make the assumptionthat a chemical is not chronically toxic at much lower concentrations than someratio of the LCSp value would suggest. Practical Utility of

### theData How will the data be used? The data will be used to estimatepotential risks to estuarinelmarine aquatic invertebrates ~nd to reduceuncertainties associated with the current ecological risk assessment. How could the data impact the Agency's future decision-making?
, Without these data, the Agency cannot determine the levels of clethodimthat could result kn adverse effectsto estuarinelmarineaquatic invertebrates. The lack ofthese data will limit)the flexibilitythe Agency and registrantshave in coming into compliance with the Endangere 

# id Species Act, and could result in use restrictions for clethodim which may otherwisebe avoided, or which are unnecessarily severe. I

estimates for freshwater fish, and allow it to define an action area for endangered species. Risk mitigation strategies (e.g., determining maximum clethodim application rate that results an RQ below the LOC) cannot be evaluated without these data. 

# 4

I Sincethe registration of clethodim, the Agency has worked to finalize its update to the datp requirements in 40 CFR Part 158. Theseupdated data requirements were promulgated in Qctober 2007. Now one freshwaterfish early life stage study is required to support all terrestrial, aquatic, forestry, and residentialturf use patterns.
II 40 

### CFR Part 158was revised to list the fish early-life stage and aquatic invertebrate life-c cle studies as separaterequirements in the data table; then identify each test organism as a fre hwater or saltwater species. For the freshwater fish early-life stage and freshwater invertebrateli e-cycle data requirements,the Agency requires testing of one fish species and one aquatic inverte rate species, respectively, for the terrestrial, aquatic, forestry, and residential turf use patterns.

# 1

Previously, the freshwater invertebrate life cycle and freshwater fish early life stagetests ere 

# 7 combinedunder one data requirement with testing required of only the more sensitive spe ies in acute studies. However, when a pesticide enters the aquatic environment,both groups of 

# , organisms are exposed. Moreover, acute sensitivityis not a reliable indicatorof chronic sensitivity, particularly when looking across different groups of organisms, so chronic dat are needed regardless of the results of acute testing. 

# 4
This change was warranted because the relative sensitivity of fish and invertebrates can va~ widely across chemicals. Previously, only the more sensitive ofthe two organisms, either 

### .- 

# I fish orable to determinethe appropriatemitigation for clethodirn. How could the data impact the Agency's futime decision-making? If future endangered species risk assessments are performed without these data, the Ag

aquatic, forestry, and residential turf use patterns when thoseuses can lead to exposure in estuarine and/or marine habitats. 

## i 40 CFR Part 158was revised to list the fish early-life stage and aquatic invertebratelife-c cle studies as separaterequirements in the data table; then identify each test organism as a fre hwater or saltwater species. For the saltwater fish early-life stage and saltwater invertebrate life- ycle data requirements,the Agency requires testing of one fish species and one aquatic kverte rate species,respectively, for the terrestrial,aquatic, forestry, and residential turf use patterns estuarine or marine habitats may be exposed to the chemical. Previously, the saltwater \hen invertebrate life cycle and saltwater fish early life stage tests were combined under one daa requirement with testing required of only the more sensitive species in acute studies. Ho

# 4 ever, when a pesticide enters the aquatic environment, both groups of organisms are exposed. 

### I Moreover, acute sensitivityis not a reliable indicator of chronic sensitivity, particularly w4en looking across different groups of organisms, so chronic data are needed regardless ofthe bults of a~ute'testin~. This change was warranted because the relative sensitivity of fish and invertebrates can v widely across chemicals. Previously, onlythe more sensitive ofthe two organisms,How could the data impact the Agency's future decision-making? registrationreview decision and for an endangered species assessment, which will be conducted as part of that decision. The effects data would be u ed to determine the likelihoodthat the chronic risks canpotentially impact aquatic communities by direct effects on fish and their reproduction. By refining the assessment, the Agency wou d be able to determine the appropriatemitigation for clethodim. 

# I

i How could the data impact the Agency's future decision-making? I If future endangered species risk assessments are performed without these data, the Agenc 

# I would have to assume that clethodim "may affect" endangered fish directly (and 1 endangered species from other taxa indirectly). Thus, use of clethodim might need to be 1 restricted in areas where endangered species could be exposed. The lack ofthese data will. the flexibilitythe Agency and registrants have in coming into compliance with the Endanyed limit Species Act and could result in use restrictions for clethodim which are unnecessarily sevqre.

### unnecessary use restrictions, and the use of clethodimmay 

### need to be restricted in 

### areas wgere endangered species occur unless these data are provided. The Agency will conduct a search of the open literatureto ensure that all best ava science is utilized. The Agency uses the ECOTOX database as its mechanism for searching the open literature for ecological effects information. ECOTOX integri three previously independentdatabases 

### - AQUIRE, PHYTOTOX, and TERRETC a system which includes toxicity data derived predominately from the peer-reviev literature, for aquatic life, terrestrial plants, and terrestrial wildlife, respectively. ible

:s 

## :

- into d

2 1

### There is specific informationthat will assist the Agency in refining the ecological assessment, including any species-specific effects determinations. The Agency is much interested in obtaining the followinginformation: 1. confirmationon the followinglabel information l 

### a. sites of application b. formulations c. application methods and equipnent d. maximum application rates e. frequencyof application, application intervals, and maximum nurn er of applications per season 

### f. geographic limitations on use relevant crops) 3. use history national, state, and county 

# !

2. use or potential use distribution (e.g., acreage and geographical distributio of

4. 

### median and 9oth percentile reported use rates (lbs. a.i.lacre) from usage dat - 

### 5. 

### application timing (date of first application and application intervals)by cr I 

### p - 

### national, state, and county 6. sub-countycrop location data of-way) 

# !

7. 

### usageluse information for non-agricultural uses (e.g., forestry, residential, r ghts8. directly acquired county-level usage data (not derived from state level data

# i

a. maximum reported use rate (lbs. a.i./acre) from usage data - 

### county b. percent crop treated - 

### county c. median and 9oth percentile number of applications - 

### county 

# I

d. total pounds per year - 

### county 

### e. the year the pesticide was last used in the countylsub-county area f. the years in which the pesticide was applied in the countylsub-coun y area 9. typical interval (days) 10. 

### state or local use restrictions 

# t

11. ecological incidents (non-target plant damage and avian, fish, reptilian, 

### am hibian and mammalian mortalities)not already reported to the Agency 

## Ip 12. monitoring data I 

### The analysisplan will be revisited and may be revised depending upon the data av in the open literature and the information submitted by the public in response to th opening of the Registrationreview docket.

### Flickinger, E.L., D.H. White, C.A. Mitchell, and T.G. Lamont. 1984. ~onocrotobhos and clethodim residues inbirds as a result of misuse of organophosphates i Matagorda County, Texas. J. Assoc. Off. Anal. Chem. 672327-828. U. S. Environmental Protection Agency. 1 

### 998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of Research and Developme Washington, D.C. EPAl630lR-951002F. April 1998. U.S. Environmental Protection Agency. 2000. Risk Characterization Handbook. Science Policy Council, U.S. Environmental Protection Agency, Washingt D.C. 20460. EPA 100-B-00-002. December 2000. U.S. Environmental Protection Agency. 2004. Overview of the Ecological Risk Assessment Process 

### in the Office of Pesticide Programs, U.S. Office of Prevention, Pesticides and Toxic Substances, Office ofPesticide Programs, Washington, D.C. January 23,2004. ProtectionAgency. Endangered and Threatened Species Effects Determin