associated with ancymidol and its degradates. It also describes the preliminary ecological risk hypothesis and analysis plan for evaluating and characterizing ri sk to non-target species in support of the registration review of ancymidol. This document also recommends studies that should be included in a generic data call-in (DCI) to addre ss uncertainties surrounding the environmental fate and potential ecological effects of ancymidol.

-2 of 46-

## Problem Formulation for the Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments in Support of the Registration Review of Ancymidol

alpha-Cyclopropyl-alpha-(4-met hoxyphenyl)-5-pyrimidylmethanol CAS Registry Number: 12771-68-5

PC Code: 108601

P

repared by: Alicia Korol, Biologist Faruque Khan, Ph.D., Senior Fate Scientist U.S. Environmental Protection Agency Office of Pesticide Programs

E nvironmental Fate and Effects Division

E nvironmental Risk Branch I V 1200 Pennsylvania Ave., NW

M

ail Code 7507P Washington, DC 20460 R eviewed by: Michael Lowit, Ph.D., Ecologist Christopher M. Koper, M.S., Chemist

March 28, 2011

-3 of 46-Table of Contents

1. Purpose ................................................................................................................... .................... 5

2. Problem Fo rmulation ....................................................................................................... .......... 5 2.1. Nature of Regulatory Action ............................................................................................. .. 5

2.2. Previous Assessments .................................................................................................... ..... 6 2.2.1. Ecological Risk Assessments ....................................................................................... 6 2.2.2. Drinking Water Exposure Assessments ....................................................................... 6

3. Stressor Source and Distribution .......................................................................................... ..... 6

3.1. Mechanism of Action .......................................................................................................... 6

3.2. Overview of Pesticide Use and Usage ................................................................................ 7

3.3. Environmental Fate and Transport...................................................................................... 8

3.5. Water Quality ................................................................................................................. ... 10 4. Receptors.................................................................................................................. ................ 10

4.1. Effects to Aquatic Organisms ........................................................................................... 11

4.2. Effects to Terrestrial Organisms ....................................................................................... 12

4.3. Incident Databases Review ............................................................................................... 14 4.4. Ecosystems Potentially at Risk .......................................................................................... 14 5. Assessment Endpoints ...................................................................................................... ....... 15 6. Conceptual Model .......................................................................................................... .......... 15 6.1. Risk Hypothesis ......................................................................................................... ....... 16 6.2. Conceptual Diagram ...................................................................................................... ... 16 7. Analysis Plan ............................................................................................................. .............. 18

7.1. Stressors of Concern .................................................................................................... ..... 18 7.2. Measures of Exposure .................................................................................................... ... 19

7.3. Measures of Effect ...................................................................................................... ...... 21 7.4. Integration of Exposure and Effects ................................................................................. 22

7.5. Deterministic and Probabi listic Assessment Methods ...................................................... 22 7.6. Endangered Species Assessments ..................................................................................... 23 7.7. Drinking Water Assessment ............................................................................................. 2 3 7.8. Preliminary Identifica tion of Data Gaps ........................................................................... 23

7.8.1. Environmental Fate .................................................................................................... 24

7.8.2. Effects Data .......................................................................................................... ...... 25

8. References ................................................................................................................ ................ 31 APPENDIX A: SIP v.1.0 Description, Assumptions, Inputs and Outputs .................................. 35

APPENDIX B: Data Call-In Tables ............................................................................................ 37

-4 of 46-1. Purpose

The purpose of this problem formulation is to pr ovide an understanding of what is known about the environmental fate and ecological effects of ancymidol, considering its currently registered uses. Ancymidol (alpha-cyclopropyl-alpha-(4 -methoxyphenyl)-5-pyrimidinemethanol; CAS No. 12771-68-5; PC Code 108601) is in the pyrimidine cl ass of pesticides which inhibit giberellin biosynthesis. When used as directed, ancymidol serves as a plant growth regulator that limits internode elongation. Ancymidol is currently registered for use on container-grown ornamentals, foliage, and bedding plants in nur series, greenhouses, shadehouses, and interiorscapes. There are no residential uses for ancymidol nor are there an cymidol formulations cla ssified as “restricted use.” This document provides a plan for an alyzing data relevant to ancymidol and for conducting environmental fate, ecological risk, endangered species, and drinking water exposure assessments for its registered uses. Additionally, this problem formulation identifies data gaps, uncertainties, and potential assumptions used to address those uncertainties relative to characterizing the potential ecological risk associat ed with the registered used of ancymidol on container-grown plants in nurseries, gr eenhouses, shadehouses, and interiorscapes.

2. Problem Formulation

2.1. Nature of Regulatory Action

Under the Federal Insecticide, F ungicide, and Rodenticide Act (FIF RA), all pesticid es distributed

or sold in the United States generally must be registered by the Environmental Protection Agency (Agency). In determining whether a pestic ide can be registered in the U.S., the Agency evaluates its safety to non-target species base d on a wide range of environmental and health effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act, and the Agency was mandated to implement a new program for the periodic review of pesticides, i.e

., Registration Review ( http://www.epa.gov/oppsrrd1/registration_review/ ). The Registration Review program is intended to ensure that, as th e ability to assess risk evolves and as policies and practices change, all register ed pesticides continue to meet the statutory standard of no

unreasonable adverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur ov er time. Through the new Registration Review program, the Agency periodically reevaluates pestic ides to make sure that as change occurs, products in the marketplace can be used safely.

As part of the implementation of the new Regist ration Review program purs uant to Section 3(g) of the Federal Insecticide, Fungi cide and Rodenticide Act (FIFRA), the Agency is beginning its evaluation of ancymidol to determine whether it continues to meet the FIFRA standard for registration. This problem formulation for the environmental fate, ecological risk, endangered species, and drinking water assessm ent chapter in support of the registration review of ancymidol will be posted in the initial docket which will open the public phase of the review process.

-5 of 46-2.2. Previous Assessments

2.2.1. Ecological Risk Assessments

Ancymidol was first registered by the Agency in 1973 by Elanco Products Co., division of Elli Lilly and Co. In 1993, the Agency issued a Data Call-In (DCI) to the re gistrant for submission of additional data. In 1995, ancymidol was gran ted reregistration. According the chemical’s Registration Eligibility Determin ation (RED), ancymidol use was determined to cause minimal adverse effects to Federally listed and nonlisted fi sh, aquatic invertebrates, aquatic plants, birds, mammals, and beneficial insects; Additionally, because very limited exposure was anticipated to terrestrial plants, minimal adverse effects we re expected to this taxa (USEPA, 1995).

After reviewing the previous risk assessment on ancymidol ( i.e. , RED), modifications to the previous risk analyses are expe cted. These changes are due to an evolution of Agency policy since ancymidol was re-registered ( e.g., evaluating drinking water exposure to birds and mammals). While taxa-specific risk assessments were conducted, these assessments were based on data sets now considered incomplete by current EPA policy, on coarse exposure estimates, and on qualitative risk determinations in some cases ( e.g. terrestrial plants). Further, label clarification of applicat ion rates is necessary for use in the final registration-review risk

assessment.

2.2.2. Drinking Water Exposure Assessments

Since no food or feed uses were registered, no dietary exposure was considered from the pesticide uses of ancymidol during the reregist ration evaluation phase. Therefore, a screening drinking water assessment has not been conducted for ancymidol. If a drinking water assessment is warranted by the Health Effects Division (HED ), a drinking water exposure assessment using up-to-date models and data will be completed during the registrati on review process. At that time, the HED will be consulted in order to determ ine which, if any, of ancymidol degradates are residues of toxicological concern and should be included in the drinking water exposure assessment in support of the human hea lth dietary risk assessment.

3. Stressor Source and Distribution

3.1. Mechanism of Action

Ancymidol is a plant growth regulator in the pyrimid ine chemical class of pesticides that inhibits gibberellin biosynthesis. When used as dire cted, ancymidol reduces internode elongation for plant height control. Hofmannova, et. al ., 2008, also demonstrated that ancymidol inhibits cellulose synthesis, which is independent of th e interference with gibe rellin biosynthesis, and which in turn inhibits cell elongation and cell wa ll deposition. Plants absorb ancymidol through the foliage, stems, roots, seed coats, and at the stage of seed germination; as such, ancymidol can be applied a multiple stages throughout a plant’s life cycle. Ancymidol is a systemic growth regulator and is translocated from point of upt ake to the terminal where it reduces internode elongation.

-6 of 46-3.2. Overview of Pesticide Use and Usage

Ancymidol is currently registered for use as a plant growth regulator in container-grown ornamental, foliage, and bedding plants in nurseries, greenhouses, shadehouses, and interiorscapes. Usages of ancymidol in nurse ries and shadehouses ar e considered as outdoor uses. Five labels are currently registered for use in the United States: two (2) manufacturing-use only products, and three (3) fo rmulated end-use products ( Table 1 ). All three end-use products contain the active ingredient, an cymidol, only, and are formulated as water based solutions for application to foliage (ABIDETM and A-Rest* Solution ® ) and seed (A-REST* Seed Treatment ® ).

Table 1. Currently Registered Ancymidol End-Use Products.

FORMULATION EPA REG.

NO. % ACTIVE METHODS OF

APPLICATION USE RESTRICTIONS

ABIDETM 62097-22 0.026 Foliar spray,

drench -Spray application must only be performed in enclosed areas, such as greenhouses, where spray

drift outside the treated area cannot occur. -Drench applications can be applied indoor or

outdoor

A-Rest* Solution ® 67690-2 0.026 Foliar spray, drench, chemigation -Chemigation is restricted in CA

ANCYMIDOL

Technical ® 62097-23 99.72 n/a -For the formulation of plant growth regulator solutions for manufacturing use only

A-REST* Seed

Treatment ® 67690-41 99.6 Seed treatment -Greenhous e use only for ornamental plant seeds

to be sown in containers

A-Rest*

Technical ® 67690-5 99.6 n/a -For the formulation of plant growth regulator products for manufacturing use only

The current formulations with labeled outdoor uses for spray, drench, and chemigation applications (ABIDETM and A-REST* Solution®) do not specify maximum application rates per plant type ( e.g. bedding plants) on the basi s of chemical weight ( e.g. lbs/pot). Instead, general guidelines are provided that recommend concentrat ions of ancymidol in solution that will be used for treatment ( i.e. 50 ppm). The labels explicitly state that the optimum rates will vary depending on the grower, desired plant height , growing conditions, ap plication technique, species, and variety or cultivar, and that the labele d use rates should act as a baseline for further

rate refinement. Maximum annual application rates per pot size, or application rates per growing season where appropriate, on a chemic al weight basis must be specified for the Environmental Fate and Effects Division (EFE D) to conduct an ecological risk assessment for all outdoor uses; maximum number of sequenti al applications per plant type must also

be defined. The risk assessment for outdoor spray, drench, and chemigation applications of ancymidol cannot be completed without this information.

For risk assessment purposes, rate sp ecifications as described above ( i.e. maximum annual application rates per pot size, or application rates per growi ng season where appropriate, on a chemical weight basis) are not necessary for labeled indoor ( i.e. greenhouse or interiorscape) uses, as these would not result in sufficient environmental exposure to necessitate an ecological

-7 of 46-risk assessment. The ancymidol seed treatment is labeled for greenhouse (indoor) use only and will not be assessed for outdoor exposures.

No national level usage data is available for an cymidol use. However, information on ancymidol

is available for the state of Ca lifornia from the California Depart ment of Pesticide Regulation for the years 2006 to 2008. From this data, ancy midol usage was reported for nursery and/or greenhouse use only (as of 07/20/10), at a to tal maximum quantity of 1.5, 1.8, and 0.8 pounds applied/entire state for the years 2006, -07, and -08, respectively. This information can be found publically at: http://www.cdpr.ca.gov /docs/pur/purmain.htm

.

3.3. Environmental Fate and Transport

Ancymidol is a pyrimidine class of pesticides and moderately sol uble (650 mg/L) compound. The vapor pressure (2.0 x 10 -7 mm Hg) and the estimated Henr y's Law Constant of 1.09 x 10 -10

atm m 3 /mol indicate that the compound is relatively non-volatile under field conditions. The noctanol water partition coefficient (Log K

ow =1.91) for ancymidol indi cates a low potential for

bioaccumulation.

Based on limited environmental fate data, the majo r route of dissipation of ancymidol in the soil is by microbial metabolism (aerobic half-life = 14.9 days). In the aerobic soil metabolism study, ancymidol mineralized to carbon dioxide, which in creased to a maximum of 44.89 percent of the applied ancymidol by 61 days post treatmen t and unextracted residues increased to approximately 43 percent at 61 days post treatment. Six unidentified degradates were detected at

≤ 0.01 ppm. Ancymidol is hydrolytically stable in pH 5, pH 7, and pH 9 buffered solutions. However, there is uncertainty about the fate of ancymidol in anaerobic soils as well as aerobic and anaerobic aquatic environments since no studies were submitted related to these conditions. No photolytic degradation in aqua tic and soil environments are avai lable at his time. In addition, the fate behavior of ancymidol under field conditions cannot be determined for lack of a field dissipation study. The chemical formula, struct ure, and the physical, chemical, environmental fate and transport characteristics associated with ancymidol are summarized in Table 2

.

Table 2. Physical, Chemical Properties and En vironmental Fate Properties of Ancymidol.

Parameter Value Reference Comments

Chemical Name Ancymidol MRID 417235-01

Chemical Family Pyrimidine MRID 417235-01

Empirical Formula C 15 H 16 N 2 O 2 MRID 417235-01

IUPAC ( RS )- α -cyclopropyl-4- methoxy- α -(pyrimidin-5- yl)benzyl alcohol MRID 417235-01

CAS Name α -cyclopropyl- α -(4- methoxyphenyl)-5- pyrimidinemethanol MRID 417235-01

-8 of 46-Parameter Value Reference Comments

Structure MRID 417235-01

Selected Physical/Chemical Parameters

Molecular mass 236.30 g/mol M RID 418212-01

Vapor pressure (25°C) 2.0 x 10 -7 mm Hg M RID 418212-01

Solubility (25°C) 650 mg/L (water) 2.5g/L (Acetone) 0.7g/L (Acetotrile) M RID 417235-01

Henry’s law constant (20°C, pH 7) 1.09 x 10 -10 Calculated HLC = (VAPR÷760) ÷ (SOL÷MWT)
Octanol-water partition coefficient (LogK O W ) (25°C) 1.91 MRID 00162638

Persistence

Hydrolysis pH 5: stable pH 7: stable pH 9: stable M RID 417235-03

Aqueous Photolysis (t 1⁄2 ) No data

--

Soil Photolysis (t 1⁄2 ) No data

--

Aerobic Soil Metabolism (t 1⁄2 ) 14.9 days M RID 420530-01 Sandy loam soil

Anaerobic Soil Metabolism No data

--

Anaerobic Aquatic Metabolism (t 1⁄2 ) No data

Aerobic Aquatic Metabolism No data

--

Mobility

Soil Partition Coefficient K f (mL/g)

0.11 (sand) 0.73 (loam) 0.55 (sandy loam) a 0.82 (clay loam soil)

K foc (mL/g )

58 (sand) 90(loam) 77 (sandy loam) 68 (clay loam soil) M RID 417235-02 There was correlation

between K f and % organic carbon. In general, adsorption appeared to increase with increasing organic

carbon content of soils.

Field Dissipation

-9 of 46-Parameter Value Reference Comments

Terrestrial Field Dissipation (t 1⁄2 ) No data

--

a MRID 419137-01, a soil column leaching study supports reported K f of 0.55 mL/g for sandy loam soil.

3.4. Degradates of Concern

Major degradates are compounds that form at greater than 10% of the applie d in at least one fate study, or are known to be toxicol ogically significant. There we re no major degradates except

CO 2 reported based on limited environmental fate studi es. No toxicity data is available for any degradate of ancymidol.

3.5. Water Quality

Ancymidol is not identified as a cause of impa irment for any water bodies under section 303(d)

of the Clean Water Act 1 . In addition, no Total Maximum Da ily Loads (TMDL) have been developed for ancymidol 2 and there are no aquatic life criteria for ancymidol 3 . More information on impaired water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/

. The Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Im paired Water Body and Other Water Quality Data in OPP’s Registration Review Risk A ssessment and Management Process (see: http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf ), in order to ensure they can be used quantitatively or qual itatively in pesticide risk assessments.

No monitoring data were available for ancymi dol. Neither the USGS’s National Water Quality Assessment (NAWQA) program nor the Califor nia Department of Pesticide Regulation monitoring programs included an cymidol as an analyte.

4. Receptors

Consistent with the process described in th e Overview Document (USEPA, 2004), the risk assessment for ancymidol relies on a surrogate speci es approach. Toxicological data generated from surrogate test species, which are intended to be representative of broad taxonomic groups, are used to extrapolate the pot ential effects on a variety of species (receptors) included under these taxonomic groupings.

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the available open literature are used to evaluate the potential direct and indirect effects of ancymidol to aquatic and terrestrial receptors. This includes toxicity on the technical grade

1 based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

, accessed January 26, 2011

2 based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl _pollutant_detail?p_pollutant_group_id=885&p_pollutant_ group_name=PESTICIDES , accessed January. 26, 2011

3 based on information provided at http://www.epa.gov/waterscien ce/criteria/aqlife/index.html

-10 of 46-active ingredient, degradates, and when available, formulated products ( e.g. , “Six-Pack” studies). The open literature studies are identified th rough EPA’s ECOTOXicology (ECOTOX) database, which employs a literature search engine for lo cating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data ma y also provide insight into the direct and indirect effects of ancymidol on biotic communities from loss of species that are sensitive to the chemical and from changes in structure and functiona l characteristics of the affected communities. Data from an ECOTOX run for ancymidol will be evaluated for possible quantitative and/or qualitative incl usion in the risk assessment in support of Registration Review. At that time, endpoints more sens itive than available guideline studies will be reviewed from the open literature studies.

A summary of the most sensitiv e data representing non-target or ganisms exposed to ancymidol in aquatic and terrestrial habita ts is provided in Section 4.1. A summary of ecological incidents associated with ancymidol and a description of ec osystems potentially at risk are provided in

Section 4.2.

4.1. Effects to Aquatic Organisms

Effects data are available on aquatic animals and plants for ancymidol; no data on aquatic organisms are available for the formulations or any degradate. Based on the available data, ancymidol is categorized as practically non-toxic on an acute exposure basis to freshwater fish

and invertebrates. There are no data available for estuarine/mari ne animals or chronic toxicity

data for freshwater animals. Da ta on aquatic vascular and nonvasc ular plants are available. A summary of all submitted aquatic animal toxicity studies are presented in Table 3.

Table 3. Summary of Submitted Aquatic Anim al Toxicity Studies for Ancymidol.

TAXON SPECIES ENDPOINT CHEMICAL/

FORMULATION MRID STUDY

CLASSIFICATION

Freshwater Fish (Acute) Rainbow Trout ( Oncorhynchu s mykiss ) 96-hr LC 50 >99.2 mg

a.i./L Ancymidol (99.9%) 41670603 Acceptable (“Core”)

Freshwater

Invertebrate (Acute) Daphnid ( Daphnia

magna ) 48-hr EC 50 >96.4 mg

a.i./L Ancymidol (99.9%) 41670601 Acceptable (“Core”)

Data from an acceptable 96-hour freshwater fish study is available for rainbow trout ( Onchorhynchos mykiss ) (MRID 41670603). The study was conduc ted as a limit test at 100 mg a.i./L (nominal) and no mortality was observed at a mean-measured concentration of 99.2 mg a.i./L for the duration of the study. Sublethal eff ects were observed in 5 of the 30 fish exposed to ancymidol and included labored re spiration, prostration, and a distended ventral surface. Based on this study, ancymidol is classi fied practically non-toxic to ra inbow trout on an acute exposure

basis.

One 48-hour freshwater invertebrate toxi city study was submitted for the daphnid, Daphnia

magna (MRID 41670601). By test termination, no mort ality or sublethal e ffects were noted. The reported EC 50 and NOAEC for this limit test were >96.4 and 96.4 mg a.i./L, respectively.

-11 of 46-Based on these results, ancymidol is cl assified practically non-toxic to Daphnia magna on an acute exposure basis.

The most sensitive species for both vascular and nonvascular aquatic plants for ancymidol from submitted toxicity studies are presented in Table 4.

Table 4. Summary of Submitted Aquatic Pl ant Toxicity Studies for Ancymidol.

TAXON ENDPOINT CHEMICAL/

FORMULATI

ON MRID STUDY

CLASSIFICATION

Aquatic Nonvascular Plants

Freshwater Green Alga ( Psuedo-kirchneriella subcapitata, formerly

Selenastrum capricornutum ) 96-hr EC 50 = 26.9 mg

a.i./L Slope: 2.91 NOAEC = 13.6 mg a.i./L (algal cell density) Ancymidol (99.8%) 43140502 Acceptable (“Core”)

Aquatic Vascular Plants

Duckweed ( Lemna gibba ) 14-day EC 50 = 0.292 mg a.i./L (frond number) Slope: 1.67 NOAEC = 0.0684 mg a.i./L (frond number) Ancymidol (99.8%) 43140501 Acceptable (“Core”)

Tier II aquatic nonvascular plant da ta on the freshwater green alga, P. subcapitata , is available for the TGAI (MRID 43140502). Algae were exposed to the six treatment concentrations of 8.14, 13.6, 23.2, 36.5, 58.4, and 98.6 mg a.i./L (mean-measured) plus a negative control for 120 hours. The resulting EC 50 and NOAEC based on cell dens ity were 26.9 (7.42-81.64) and 13.6 mg a.i./L, respectively.

Data on the TGAI from an acceptable 14-day Tier II aquatic vascular plant study is available for duckweed ( L. gibba ) (MRID 43140501). Duckweed was exposed to seven treatmentconcentrations of 0.0154, 0.0312, 0.0684, 0.151, 0.263, 0.523, and 1.06 mg a.i./L (meanmeasured) plus a negative c ontrol. The resulting EC 50 and NOAEC based on frond number were 0.292 (0.193-0.488) and 0.0684 mg a.i./L, respectively.

4.2. Effects to Terrestrial Organisms

Table 5 summarizes the all of the terrestrial animal ecological toxicity en dpoints for ancymidol and its formulations based on an evaluation of submitted studies. Ancymidol is categorized as practically nontoxic to birds on a subacute dietary exposure basis and is slightly toxic to mammals on an acute oral exposure basis. An cymidol is practically nontoxic to young adult honey bees on an acute contact exposure basis. No chronic data has been submitted for terrestrial animal exposure to ancymidol. Like wise, no data on exposures of ancymidol to terrestrial plants has been submitted.

Table 5. Summary of the Submitted Terrestria l Toxicity Studies for Ancymidol.

TAXON ENDPOINT CHEMICAL/

FORMULATION MRID STUDY

CLASSIFICATION

-12 of 46-TAXON ENDPOINT CHEMICAL/

FORMULATION STUDY MRID CLASSIFICATION

BIRDS Sub-Acute Dietary Bobwhite quail ( Colinus virginianus ) 8-day LC 50 > 5192 mg a.i./kg-diet Ancymidol (99.9%) 4167060 2 Acceptable (“Core”)

MAMMALS

Acute Laboratory Rat ( Rattus norvegicus ) LD 50 = 1016 mg/kgbw (females) Ancymidol (100%) 42480601 Acceptable

Laboratory Rat ( Rattus norvegicus ) LD 50 > 4965 mg/kg bw (males and females) A-Rest* Solution® (0.0264%) 00162642 Acceptable

Laboratory Rat ( Rattus norvegicus ) LD 50 > 2000 mg/kg bw (females) ABIDETM (0.0264%) 47331303 Acceptable

TERRESTRIAL INVERTEBRATES

Acute

Honey Bee (Apis melifera) 48-hr LD 50 >100 μg

a.i./bee Ancymidol (99.8%) 4314050 4 Acceptable (“Core”)

An acceptable avian dietary toxici ty study with bobwhite quail ( Colinus virginianus ) is available for ancymidol (MRID 41670602); the resulting 8-day LD 50 was > 5192 mg a.i./kg diet based on no mortality in the control and treatment groups. The corresponding NOAEC was 2638 mg a.i./kg-diet based on significant reduction in mean body weight in the 5192 mg a.i./kg diet treatment group. No reductions in feed consum ption were observed in any treatment group. Necropsy of birds was conducted on the eyes, and while one bird revealed bilate ral congenital cortical cataracts, this condition was not consider ed treatment related. All birds were normal in appearance and behavior throughou t the study except for one bird (at 5192 mg a.i./kg diet) who was constantly pacing the cage with its head droo ping. This effect was notconsidered treatmentrelated by the study author. Based on these result s, ancymidol is categorized as practically nontoxic to bobwhite quail on a subacute dietary basis.

An acute oral toxicity study with rats has b een submitted for the TGAI, and the formulations ARest* Solution® (0.0264%) and ABIDETM (0.0264%). The test design of the study using the TGAI (MRID 42480601) included three treatments groups at 750, 1375, and 2500 mg a.i./kg bw and a vehicle control group. Deaths of all rats occurred after oral gavage at the highest treatment level by day 4, and in 1/5 males and 5/5 fema les in the 1375 mg a.i./kg bw dose group. The resulting male and female LD 50 = 1721 mg a.i./kg bw and 1016 mg a.i./kg bw, respectively. Clinical signs of toxicity were observed in th e three highest dose groups; both males and females in the 750 mg ai/kg bw dose group exhibited hypo activity, tremors, generalized leg weakness, ataxia, lethargy, bloody tears, colo red nasal discharge, and hunched posture (females only). In the 1375, and 2500 mg a.i./kg bw dose groups, clonic convulsions and salivation was observed in all animals; other clinical signs of toxicity exhibited by some rats included coma, lethargy, hunched posture, immobilization, bloody tears, colored nasal discharge, poor grooming, piloerection, lack of feces , and anterior soiling.

In the acute oral rat toxicity study on A-Rest* Solution® (0.0264%) (MRID 00162642), two groups of 5 male and 5 female rats were oral dosed with either 479 or 4965 mg form/kg bw. No

-13 of 46-mortality occurred in either group. Toxic signs of dosing included leg weakness and soft stools. The resulting LD 50 for both male and female rats was > 4965 mg form/kg bw. In an acute oral toxicity study on ABIDETM (0.0264%) (MRID 47331303) , two groups of three female rats were given single oral gavage doses of 2000 mg/kg bw. There were no deaths, abnormal clinical signs, or treatment-related gro ss necropsy findings at the end of the study (end of the 14 day observation period). The resulting LD 50 based on female rats was > 2000 mg a.i./kg bw.

Ancymidol is classified practically non-toxic to young adult honey bees ( Apis mellifera ) based on the one acute contact toxicity stud y (MRID 43140504). The resulting 48-hour LD 50 and NOAEL based on mortality in bees is >100 μg a.i./b ee and 100 μg a.i./bee, re spectively. Clinical observations in all treatment groups were comparable to the control groups.

4.3. Incident Databases Review

Preliminary reviews of the Ecological Incident Information System (EIIS, version 2.1) and the Avian Incident Monitoring System (AIMS) 4 were conducted on January 21, 2011. No incidents involving ancymidol were f ound in these databases.

In addition to the incidents recorded in EIIS, ad ditional incidents are reported to the Agency in aggregated form. Pesticide registrants report certain types of incide nts to the Agency as aggregate counts of incidents occu rring per product per quarter. Ecological incidents reported in aggregate reports include those categorized as ‘mi nor fish and wildlife’ (W -B), ‘minor plant’ (PB), and ‘other non-target’ (ONT) incidents. ‘O ther non-target’ incidents include reports of

adverse effects to insects and ot her terrestrial invertebrates. For ancymidol, as of January 21, 2011, there have been no reported aggregated incidents associated with ancymidol.

The total number of actual incide nts associated with the use of ancymidol may be higher than what is reported to the Agency. Incident s may go unreported since effects may not be immediately apparent and/or readil y attributed to the use of a chem ical. As such, the absence of incident reports cannot be construe d as the absence of incidents.

4.4. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scop e; therefore, it may not be possible to identify specific ecosystems during the development of a nation-wide ecological risk assessment. However, in general terms, terrestrial ecosyst ems potentially at risk from ancymidol exposure could include the treated nursery ground and adja cent areas that may receive drift or runoff. Areas adjacent to the treated containerized plants within or beyond the nursery grounds could include cultivated fields, fen cerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats a nd other uncultivated areas.

4 http://www.abcbirds.org/abcprograms/ policy/pesticides/aims/aims/index.cfm

-14 of 46-Aquatic ecosystems potentially at risk include wa ter bodies adjacent to, or downstream from, the treated area and could include impounded bodies such as ponds, lakes and reservoirs, or flowing waterways such as streams or rivers. For uses in coastal areas, aquati c habitat also includes marine ecosystems, including estuaries.

5. Assessment Endpoints

Assessment endpoints represent the ac tual environmental value that is to be protected, defined by an ecological entity (species, community, or othe r entity) and its attri bute or characteristics (USEPA, 1998 a ). For ancymidol, the ecological entitie s may include the following: birds, mammals, terrestrial-phase amphibian s, reptiles, freshwater fish a nd invertebrates, aquatic-phase amphibians, estuarine/marine fish and invertebrate s, terrestrial plants, terrestrial invertebrates, and aquatic plants. The attributes for each of these entities include growth, reproduction, and

survival.

6. Conceptual Model

For a pesticide to pose an ecological risk, it mu st reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a pesticide moves in the environment from a source to an ecological recepto r. For an ecological pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, an d a feasible route of exposure.

The conceptual model for ancymidol provides a wr itten description and visual representation of the predicted relationships betw een ancymidol, potential routes of exposure, a nd the predicted effects for the assessment endpoint. A conceptual model consists of two major components: risk hypothesis and a conceptual diagram (USEPA, 1998).

Based on the limited submitted environmental fate data, ancymidol is not expected to volatilize and ancymidol persistence in surface waters is uncertain. Dissipati on and degradation of ancymidol in aquatic environments cannot be de termined due to lack of environmental fate studies. Column leaching study suggests that ancymidol has potential to leach through subsurface to ground water. Due to ancymidol’s log K

ow value of 1.91, more information is needed to determine the potential of the chemi cal to bioaccumulate in aquatic or terrestrial

environments.

The previous ecological risk assessment for ancy midol identified minimal adverse effects to listed and nonlisted fish, aquatic i nvertebrates, aquatic plants, birds, mammals, beneficial insects, and terrestrial plants from nursery use on containe rized plants only. Howeve r, this determination was based on an incomplete dataset and undeterm ined maximum applicati on rates, and risks to most taxa ( i.e. , birds, mammals, fish, aquatic invertebra tes, and plants) are uncertain. These preliminary conclusions are used to derive the risk hypothesis a nd conceptual diagram discussed

below.

-15 of 46-6.1. Risk Hypothesis

A risk hypothesis describes the predicted re lationship among the stre ssor, exposure, and assessment endpoint response along with the rationale for their selection. Because data are either not available or are incomplete with which to assess acute and chronic effects across multiple taxa ( i.e. birds, mammals, fish, aquatic invertebrates, and plants), and because exposures levels to non-target organisms have not been determine d, there is uncertainty re garding potential risks to these taxa. Based on the lack of data, th e following ecological risk hypothesis is being employed for this ecological risk assessment:

Given the uses of ancymidol as a plant grow th regulator in container-grown plants in nursery production and its environmental fate properties, there is potential exposure from ancymidol and its degradates of con cern to non-target terrestrial and aquatic organisms. When used in accordance with the label, ancymidol and its degradates may result in potential adverse ef fects upon the survival, gr owth, and reproduction of nontarget terrestrial and aquatic organisms.

6.2. Conceptual Diagram

The environmental fate properties of ancymidol i ndicate that runoff, spray drift and direct spray represent potential transport mechanisms to aquatic and terrestrial habitats where non-target organisms may be either directly or indir ectly exposed. These transport mechanisms ( i.e

., sources) are depicted in the conceptual diagrams below ( Figures 1 and 2 ) along with the receptors of concern and the potential attribute changes in the receptors due to exposures of ancymidol. While not captured in Figure 2 , exposure of terrestrial vertebrates from drinking water containing ancymidol and degradates of con cern is also a route of exposure that will be

assessed.

-16 of 46-Stressor

Source

Receptors

Attribute Change Ancymidol and Degradates of Concern applied to use site

Spray drift

Aquatic animals

Invertebrates

Vertebrates

Individual organisms

Reduced survival Reduced growth Reduced reproduction Food chain

Reduction in nonvascular and vascular plants Reduction in prey

Modification of PCEs

related to prey availability Habitat integrity Reduction in primary productivity

Reduced cover Community change

Modification of PCEs related to

habitat Surface water/

Sediment Runoff

Aquatic Animals

Invertebrates

Vertebrates Exposure

Media

Uptake/gills or integument

Ingestion Ingestion Atmospheric transport

Wet/dry deposition Soil Leaching to

Groundwater

Uptake/gills or integument

Aquatic Plants

Non-vascular

Vascular Uptake/cell,
roots, leaves Riparian plants

terrestrial

exposure pathways see Figure 2

FIGURE 1. Conceptual Model for Ancy midol and Degradate Effects on Aquatic Organisms. Dotted Lines Indicate Exposure Pathwa ys that Have a Low Likelihood of Contributing to Ecological Risk.

-17 of 46-Stressor

Source

Attribute Change Ancymidol and Degradates of Concern applied to use site

Direct application Spray drift

Terrestrial

vertebrates Terrestrial

inverts

Individual organisms

Reduced survival Reduced growth Reduced reproduction Food chain Reduction in prey and food

Modification of PCEs

related to prey availability Habitat integrity Reduction in primary productivity

Reduced cover Community change

Modification of PCEs related

to habitat Terrestrial plants grasses/forbs, fruit, seeds (trees, shrubs) Runoff

Terrestrial

Vertebrates Exposure Media & Receptors Soil

Ingestion Ingestion Ingestion Dermal uptake/Ingestion Atmospheric transport

Root uptake/contact

Wet/dry deposition

Ingestion Leaching to

Groundwater Irrigation

water

FIGURE 2. Conceptual Model for Ancymi dol and Degradate E ffects on Terrestrial Organisms . Dotted Lines Indicate Exposure Path ways that Have a Low Likelihood of Contributing to Ecological Risk.

7. Analysis Plan

In order to address the risk hypot hesis, the potential for adverse effects on the environment will be estimated. The use, environmental fate, and ecological effects of ancymidol will be characterized and integrated to assess the ri sks. Risk quotients (RQ) will be derived for ancymidol by dividing estimated environmental concentrations (EEC) by the most sensitive endpoint from the relevant, availa ble toxicity data for ancymidol.

This analysis plan will be re visited and may be revised dependi ng upon a full review of the data available in the open literature and the inform ation submitted by the public in response to the opening of the Registration Review docket.

7.1. Stressors of Concern

The stressors, or residues, of concern in th is assessment will incl ude ancymidol and any degradates determined to be of toxicological concern. Limited environmental fate data of

-18 of 46-ancymidol suggest that CO 2 is the major degradate with si x unidentified minor degradates formed in soil. Thus, the stressors of concern fo r this assessment will include ancymidol, as well as any other degradates determined to be of t oxicological concern at the time the risk assessment is completed. Data sources which will be used in future assessment in cluded: 1) registrant submissions in support of registration review, 2) publicly available l iterature on ecological effects, 3) monitoring data for freshwater stream s, lakes, reservoirs, and estuarine areas, 4) incident reports of adverse effects on aquatic and terrestrial organisms associated with the use of ancymidol.

The Agency does not routinely include an evalua tion of mixtures of act ive ingredients in its ecological risk assessments, either those mixtur es of multiple active ingredients in product formulations or those in the applicator’s tank. In the case of the product formulations of active ingredients (that is, a registered product contai ning more than one active ingredient), each active ingredient is subject to an indi vidual risk assessment for regula tory decision regarding the active ingredient on a particular use site. If eff ects data are available for a formulated product containing more than one active ingredient, the da ta may be used qualitatively or quantitatively in accordance with the Agency’s Overview Document and the Services’ Evaluation Memorandum (USEPA, 2004; U SFWS/NMFS, 2004).

Ancymidol is not currently formulated with other pesticide active ingredients. An evaluation of environmental mixtures of ancymidol with other pe sticides will not be presented as part of the ecological risk assessment.

7.2. Measures of Exposure

In order to estimate risks of an cymidol exposures in aquatic and terrestrial environments, all exposure modeling and resulting risk conclusion s will be made based on maximum application rate for the currently registered use as discusse d in Section 3.2. Measures of exposure are based on aquatic and terrestrial models that estimate environmental concentrations of ancymidol using the maximum labeled application ra te and application methods that have the grea test potential for off-site transport of the chemical. The models used to generate aquatic estimated environmental concentrations ( EEC) are the Pesticide Root Zone Model (PRZM) coupled with the EXposure Analysis Model System (EXAMS). The EECs will be based on the parent compound as well as any other degradates that ar e determined to be of toxicological concern based on information available at the time of the assessment. The model used to produce

terrestrial EECs on food items is T-REX. The model used to derive EECs relevant to terrestrial and wetland plants is TerrPlant. These models are parameterized using relevant reviewed registrant-submitted environmental fate data.

PRZM (v3.12.2, May 2005) and EXAMS (v2.98.4.6, Ap ril 2005) are screening simulation models coupled with the graphical user interf ace, PE (v5.0, November 2006) to generate daily exposures and 1-in-10-year EECs of ancymidol (a nd residues of concern) that may occur in surface water bodies adjacent to application sites receiving ancy midol through runoff and spray drift. PRZM simulates pesticide application, movement and transformation on an agricultural field and the resultant pesticide loadings to a receiving water body via runoff, erosion, and spray

drift. EXAMS simulates the fate of the pesticide and resulting concentrati ons in the water body. The standard watershed geometry used for ecolo gical pesticide assessments assumes application

-19 of 46-to a 10-hectare agricu ltural field that drains into an adjace nt 1-hectare water body that is 2 meters deep (20,000 m 3 volume) with no outlet. The com posite model PRZM/EXAMS is used to estimate screening-level exposure of aquatic orga nisms to ancymidol. The measure of exposure for aquatic species is the 1-in-1 0-year peak or rolling mean concentration. The 1-in-10-year peak is used for estimating acute exposures of di rect effects to aquatic organisms. The 1-in-10- year 60-day mean is used for assessing the eff ects to fish and aquatic-phase amphibians from chronic exposure. The 1-in-10-year 21-day mean is used for assessing the effects on aquatic invertebrates from chronic exposure.

Exposure estimates for terrestrial an imals assumed to be in the target area or in an area exposed to spray drift are derived using the T-REX model (version 1.4.1, 10/08/2008). This model incorporates the Kenaga nomogr aph, as modified by Fletcher et al. (1994), which is based on a large set of actual field residue data. The upper limit values from the nomograph represent the

95 th percentile of residue values from actual field measurements (Hoerger and Kenaga 1972).

The Fletcher et al. (1994) modifications to the Kenaga nomograph are based on measured field residues from 249 published research papers, including information on 118 species of plants, 121 pesticides, and 17 chemical classes. For input into T-REX, the defa ult foliar dissip ation half-life of 35 days will be used due to insufficient foliar dissipation rate data on ancymidol. If terrestrial plant toxicity data are available, EECs for terr estrial plants inhabiting dry and wetland areas are derived using TerrPlant (version 1.2.2, 12/26/2006). This model uses estimates of pesticides in runoff and in spray drift to calculate EECs. EEC s are based upon solubilit y, application rate and minimum incorporation depth.

The AgDRIFT spray drift model (v2.01; May, 2001) is used to assess exposures of organisms to ancymidol deposited on terrestrial habitats by spray drift.

The Screening Imbibition Program (SIP v.1.0, Released June 15, 2010) was used to calculate an upper bound estimate of drinking wa ter exposure alone using ancymi dol’s solubility (650 mg/L at 20°C), the most sensitive acute and ch ronic avian toxicity endpoints (avian LD 50 unavailable; avian NOAEC unavailable) and the most sensit ive acute and chronic mammalian toxicity endpoints (laboratory rat LD 50 >1,016 mg a.i./kg-bw; labor atory rat NOAEL unavailable). Appendix A provides a description of the model a nd assumptions in deriving an upper bound exposure estimate. Due to lack of data, SIP generated results for acu te exposure to mammals, only. When more toxicity data become ava ilable, upper bound estimates of chronic drinking water exposure to mammals and acute and chronic exposure to birds will be generated. Drinking water exposure alone was determined to be a potential concern for mammals on an acute basis (see Appendix A for model results). This pathway will be explored further with the development of SIP v.2.0 in the Ecological Risk Assessment fo r ancymidol. Detailed information about the SIP v.1.0, as well as the tool, can be found on the EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial

.

STIR v.1.0, S creening T ool for I nhalation R isk, is used to provide an upper bound estimate of exposure of birds and mammals to pesticides th rough inhalation of spray drift or vapor. The upper bound exposure estimate requires a number of input parameters including the vapor pressure and molecular weight for the vapor- phase pesticide; additionally it requires the application rate and method of application ( i.e. , ground or aerial) for spra y drift. The toxicity

-20 of 46-aspect of the tool requires an avian acute oral LD 50 value (the model provides an estimate of avian inhalation toxicity in the absence of such data), the chemical specific avian allometric scaling factor to adjust toxicity based on body we ight for the chemical (i f available), the weight of the tested bird, a rat acute oral LD 50 value, a rat acute inhalation LC 50 value, the duration of the rat inhalation study, and the weight of the tested rat. This tool was designed for use in the Problem Formulation phase of th e ecological risk assessment proc ess to quantitat ively evaluate the need for further analysis of inhalation as a pot ential pathway of concern for birds and mammals. Because the maximum application rates for ancymidol are unknown, a screening analysis of inhalation risk with STIR v.1.0 will be conducted at th e final risk assessment stage of registration review once the maximum applica tion rates for all outdoor uses have been determined. If further analys is of the inhalation exposure pa thway is recomm ended, additional data will be requested to address uncertainty related to this route of exposure. Detailed information about the SIP v.1.0, as well as th e tool, can be found on the EPA’s website ( http://www.epa.gov/pesticides/s cience/models_pg.htm#terrestrial ).

7.3. Measures of Effect

Ecological effects data are used as measures of di rect and indirect effects to biological receptors. As discussed previously, data are obtained from registrant-submitted studies or from literature studies identified by ECOTOX. The ECOTOX databa se provides more ecological effects data in an attempt to bridge existing data gaps. EC OTOX is a source for locating single chemical toxicity data and potential chemical mixture toxicity data for aqua tic life, terrestrial plants, and

wildlife. ECOTOX was created and is mainta ined by the USEPA, Office of Research and Development, and the National Health and Envi ronmental Effects Research Laboratory's MidContinent Ecology Division.

Also as discussed previously, information on the potential eff ects of ancymidol on non-target animals is also collected from the Ecologica l Incident Information System (EIIS; USEPA,

2007 c ). The EIIS is a database containing advers e effect (typically mortality) reports on nontarget organisms where such effects have b een associated with the use of pesticides.

Incidents reported in the aggreg ate incident reports and the Av ian Incident Monitoring System (AIMS) will also be searched. AIMS is a database administered by the American Bird Conservancy with partial funding from EPA). It contains public ly available data on reported avian incidents involving pesticides ( http://www.abcbirds.org/abcprograms/ policy/pesticides/aims/aims/index.cfm ).

Where available, sub-lethal effects observed in both registrant-submitted and open literature studies will be evaluated qualitatively. Such effects may include behavioral changes ( e.g. , lethargy and changes in colora tion). Quantitative assessments of risks, though, are limited to those endpoints that can be di rectly linked to the Agency’s assessment endpoints of impaired survival, growth and reproduction.

-21 of 46-The assessment of risk for direct effects to non-target organisms makes the assumption that toxicity of ancymidol to birds is similar to te rrestrial-phase amphibians and reptiles. The same assumption is made for fish a nd aquatic-phase amphibians.

The acute measures of effect used fo r animals in this assessment are the LD 50 , LC 50 and EC 50

. LD stands for "Lethal Dose", and LD 50 is the amount of a material, given all at once, that is

estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration”

and LC 50 is the concentration of a chemical that is estimated to kill 50% of the test organisms.

EC stands for “Effective Concentration” and the EC 50 is the concentration of a chemical that is estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic measures of exposure for listed and non-lis ted animals are the NOAEL/NOAEC and NOEC.

NOAEL stands for “No Observed-Adverse-Effect-Level ” and refers to the hi ghest tested dose of a substance that has been reported to have no harm ful (adverse) effects on test organisms. The NOAEC ( i.e. , “No-Observed-Adverse-Effect-Concentration” ) is the highest test concentration at

which none of the observed effects were statistically different fr om the control. The NOEC is

the No-Observed-Effects-Concentration. Fo r non-listed plants, only acute exposures are assessed ( i.e. , EC 25 for terrestrial plants and EC 50 for aquatic plants); for listed plants either the

NOAEC or EC 05 is used.

7.4. Integration of Exposure and Effects

Risk characterization is the inte gration of exposure and ecological effect characterizations to determine the potential ecological risk from the use of ancymidol and the likelihood of direct and indirect effects to non-target organisms in aquatic and terrestrial habitats. The exposure and effects data are integrated in order to evaluate pot ential adverse ecological effects on non-target species. For the assessment of ancymidol risks, the risk quotie nt (RQ) method is used to compare estimated exposure and measured toxicity values. Acute and chronic EECs are divided by acute and chronic toxicity values. The resu lting RQs are then compared to the Agency’s Levels of Concern (LOC) (USEPA 2004). These criteria are used to indicate when ancymidol’s use, as directed on the labels, ha s the potential to cause adverse di rect or indirect effects to nontarget organisms. In addition, incident data from EIIS, aggregate inci dent reports, and AIMS will be considered as part of the risk characterization.

7.5. Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the deterministic point estimatebased approach described in th e risk assessment. Depending on the risk manager’s need for additional information regarding risk, an effort will be made to further qualitatively describe risk using probabilistic tools that the Agency has developed. These tools have been reviewed by FIFRA Scientific Advisory Panels ( http://www.epa.gov/sc ipoly/sap/index.htm ) and have been deemed as appropriate means of refining asse ssments where deterministic approaches have

identified risks.

-22 of 46-7.6. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to Federally-listed th reatened and/or endangere d (listed) species from registered uses of ancymidol. This assessmen t will be conducted in accordance with the Overview Document (USEPA, 2004), provi sions of the ESA, and the Services’ Endangered Species Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associ ated with the registration of ancymidol is based on an action

area. The action area is considered to be the ar ea directly or indirectly affected by the federal action, as indicated by the exceedance of Agency Le vels of Concern (LOCs) used to evaluate

direct or indirect eff ects. The Agency’s approach to defi ning the action area under the provisions of the Overview Document (USEPA, 2004) consider s the results of the ri sk assessment process

to establish boundaries for that action area with the understanding that exposures below the Agency’s defined LOCs constitute a no-effect threshold. For th e purposes of this assessment,

attention will be focused on the footprint of the action ( i.e ., the area where ancymidol application occurs), plus all areas where offsite transport ( i.e ., spray drift, runoff, etc .) may result in potential exposure that exceeds the Agency’s LOCs. Specific measures of ecological effect that define the action area for listed species include any direct and indi rect effects and/or potential modification of its critical habitat, including reduction in survival, growth, and reproduction as well as the full

suite of sub-lethal effects availabl e in the effects literature. Ther efore, the action area extends to a point where environmental exposures are below any measured lethal or sub-lethal effect threshold for any biological entity at the whole organism, organ, tissue, and cellular level of organization. In situations where it is not po ssible to determine the threshold for an observed effect, the action area will be assumed to encompass the entire United States.

7.7. Drinking Water Assessment

If a drinking water assessment is warranted by the Health Effects Division (HED), a drinking water exposure assessment using up-to-date m odels and data will be completed during the registration review process. The drinking wate r assessment will incorporate model estimates of ancymidol residues of concern, including parent and any degradates of to xicological concern, in surface water and ground water. Concentrations of ancymidol and its residues of concern in surface water will be estimated using PRZM/EXAMS (see description in Section 7.2 ). Ground water exposure estimates for ancymidol and its re sidues of concern will be estimated using the Screening Concentration in Ground Water (SCI -GROW) model (v.2.3, July 2003) followed by a higher tier model if necessary. The drinking wa ter assessment will also include a summary of available surface and ground water monitoring data.

7.8. Preliminary Identification of Data Gaps

The following two sections, 7.8.1. and 7.8.2. , identify the remaining fate and effect studies needed to complete an environmental fate a nd ecological risk assessment in support of the registration review of the labe led outdoor uses of ancymidol. No fate and effect studies are

-23 of 46-needed to support registration revie w of the labeled indoor uses ( i.e. , seed treatment, greenhouse, and/or interiorscape uses).

7.8.1. Environmental Fate Data

The studies submitted to fulfill environmental fate data requirements for labeled outdoor uses of ancymidol are not sufficient for an environm ental exposure assessment. Eight guideline requirements have not been satisfied: (1) There is no acceptable photolytic degradation in water; (2) There is no acceptable photoly tic degradation in soil; (3) The current supplemental aerobic soil metabolism study will be used for risk assessment purposes, however an additional acceptable study with multiple soils is required to fulfill the guideline and better understand the potential variability in the biotic degradation of ancymidol in terrestrial environment; (4) There is no acceptable anaerobic biotic degradation in soil; (5) There is no acceptable aerobic aquatic metabolism study in sediment; (6) There is no an aerobic aquatic metabolism study in sediment; (7) There is no acceptable terrestrial field di ssipation study; (8) There is no bioaccumulation study.

Table 6 identifies studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not furthe r data are needed in order to support risk assessment ( i.e. , whether there is a data gap). Draft Data Call-In (DCI) tables for requested data are provided in APPENDIX B

.

TABLE 6. Environmental Fate Data Requirement Table for Ancymidol.

OPPTS

Guideline Data Requirement Submitted

Studies (MRID) Classification Data Gap? Comment

835.2120 Hydrolysis 4 17235-03 Acceptable No

835.2240 Aqueous photolysis Nneo
-- Yes

835.2410 Soil photolysis None
-- Yes

835.4100 Aerobic soil

metabolism 420530-01 Acceptable Yes Aerobic soil metabolism study was performed on one soil only. OSCPP requires multiple soils to reduce uncertainty. Three more studies are required.

835.4200 Anaerobic soil

metabolism None
-- Yes Data requirements include both studies.

835.4300 Aerobic aquatic

metabolism None
-- Yes Multiple deficiencies including inadequate duration of study and failure to demonstrate patterns of formation and decline of degradates.

835.4400 Anaerobic aquatic

metabolism None
-- Yes Data are needed for two additional sediment systems, one each at a neutral and an acidic pH.

835.1230 Adsorption/ desorption and leaching 417235-02 Acceptable

No Also includes ancillary data on aerobic soil

metabolism.

419137-01 Acceptable Also includes ancillary data on aerobic soil

metabolism.

-24 of 46-OPPTS

Guideline Data Requirement Submitted

Studies Classification Data Gap? Comment (MRID)

835.6100 Terrestrial field dissipation None
--

Yes A frozen storage stability study has not been

submitted.

Currently under review

Freezer storage stability None -- Data from another study (MRID 43003434)

show extracted residues decreased as a result of frozen storage prior to analysis. An acceptable freezer storage stability study using

the soils used in the TFD studies is needed.

Analytical method

– soil None

-- Yes

Analytical method

– water None

-- Yes

Analytical method

- sediment None
-- Yes

850.1730 Fish

bioconcentration None
-- No Log K

ow value of 1.91 indicates a low potential for ancymidol to bioconcentrate in fish (log Kow > 3); therefore a study is not required under 40 CFR part 158 Subpart G.

7.8.2. Ecological Effects Data

Only six (6) ecological effect data requirements have been fulfilled for the currently registered outdoor uses of ancymidol; 15 add itional data gaps remain across aquatic and terrestrial plant and animal taxa ( Tables 7-9 ). Data gaps include the following tests: avian acute oral, avian subacute dietary, avian reproduction, acute freshw ater and estuarine/marine fish, acute estuarine/marine invertebrates, chronic freshwater fish and invertebrates, algae, and terrestrial plants. No chronic toxicity data on ancymidol has yet been submitted the Agency. Although not an ecological effects data gap, a chronic 2-ge neration toxicity study in mammals is also unavailable. The data gaps are di scussed in detail below. Draf t Data Call-In (DCI) tables for requested data are provided in APPENDIX B

.

-25 of 46-TABLE 7. Available Ecological Effects Da ta for Terrestrial Animals Exposed to Ancymidol and Remaining Data Gaps.

Guideline Description MRID/

Accession Classification Data Gap? Comments

850.2100 Avian acute oral toxicity – upland game

or waterfowl species None Not applicable Yes *Avian acute oral toxicity data

are not available for passerines, which are required

under the new 40 CFR Part 158. Therefore, this is identified as a data gap. Avian acute oral toxicity – passerine species None Not applicable Yes*

850.2200 Avian sub-acute dietary toxicity – upland game species 41670602 Acceptable No

Avian sub-acute dietary toxicity – waterfowl species None Not applicable Yes

850.2300 Avian reproduction – upland game species None Not applicable Yes

Avian reproduction –

waterfowl species None Not applicable Yes

850.3020 Honeybee acute contact toxicity 43140504 Acceptable No

-26 of 46-TABLE 8. Available Ecological Effects Data for Aquatic Animals Exposed to Ancymidol and Remaining Data Gaps.

Guideline Description MRID/

Accession Classification Data Gap? Comments

850.1075 Acute freshwater fish – cold water species 41670603 Acceptable No * Toxicity data for freshwater fish and invertebrates, which are required, are not currently available. Therefore, these are identified as data gaps.

**Conditional data requirement not triggered based on available ecotoxicity data, anticipated environmentally relevant concentrations, and use pattern criteria; Conditional data requirement will be

reconsidered once additional fate and toxicity data, and application information have

been submitted. Acute freshwater fish – warm water species None Not applicable Yes*

850.1010 Freshwater

invertebrates – acute toxicity 41670601 Acceptable No

850.1075 Acute estuarine/

marine fish None Not applicable Yes*

850.1025

850.1055 Acute estuarine/

marine mollusk None Not applicable Yes*

850.1035

850.1045 Acute estuarine/

marine invertebrate None Not applicable Yes*

850.1300 Freshwater

invertebrate – life cycle test None Not applicable Yes*

850.1350 Saltwater invertebrates

– life cycle test None Not applicable No**

850.1400 Freshwater fish – early life stage test None Not applicable Yes*

850.1400 Saltwater fish – early life stage test None Not applicable No**

850.1500 Fish life cycle test None Not applicable No**

850.1735

850.1740 Whole Sediment Acute

Invertebrates None Not Applicable No**

-27 of 46-TABLE 9. Available Ecological Effects Data for Plants Exposed to Ancymidol and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? Comments

850.4100 Terrestrial Plant toxicity: Tier I seedling

emergence None Not applicable No Tier I toxicity data for terrestrial plants are not required for known phytotoxicants , such as plant growth regulators

850.4225 Terrestrial Plant toxicity: Tier II seedling

emergence None Not applicable Yes Study is required on the TEP (typical end-use product)

850.4150 Terrestrial Plant toxicity: Tier I vegetative vigor None Not applicable No Tier I toxicity data for terrestrial plants are not required for known phytotoxicants, such as plant growth regulators

850.4250 Terrestrial Plant toxicity: Tier II vegetative vigor None Not applicable Yes Study is required on the TEP (typical end-use product)

850.5400 Aquatic Plant Growth: algae – freshwater green alga 43140502 Acceptable No Data were submitted on P. subcapitata using the TGAI.

Aquatic Plant Growth:

algae – freshwater

diatom None Not applicable Yes Study is required with either the TGAI or TEP; EFED prefers a representative TEP

Aquatic Plant Growth: algae – saltwater diatom None Not applicable Yes Study is required with either the TGAI or TEP; EFED prefers a representative TEP

Aquatic Plant Growth: algae –Cyanobacteria None Not applicable Yes Study is required with either the TGAI or TEP; EFED prefers a representative TEP

850.4400 Aquatic Plant Growth: vascular plants 43140501 Acceptable No Data were submitted on L. gibba using the TGAI

Avian Acute Oral, Sub-ac ute Dietary, and Reproduction Toxicity Studies

Acute avian oral toxicity data ar e not available for ancymidol. Av ian acute oral toxicity data on passerines are required under the current 40 CFR Part 158 (July 1, 2009) data requirements for conventional pesticides (72 FR 60934; USEPA 2007 d ). The Part 158 data requirements specify that avian acute oral toxicity data (OCSPP Guideline 850.2100) be submitted for either an upland game or waterfowl species and a passerine spec ies. Due to the reported sublethal effects (reduction in mean body weight) in bobwhite quail to ancymidol , adverse sub-acute dietary

effects to birds have been demonstrated and risk to birds from ancymidol use is uncertain. EFED recommends requesting two avian acute oral st udies at this time according to the data requirements for an outdoor use chemical. The re gistrant will need to submit a passerine study

-28 of 46-protocol for review by the Agency prior to ini tiation of the passerine study. EFED will assume

risk to birds on an acute oral basi s in the absence of these data.

Under the 40 CFR Part 158 (July 1, 2009) data re quirements for conventional pesticides, avian sub-acute dietary toxicity da ta are required on waterfowl and upland game species (OCSPP Guideline 850.2200). Currently, an acceptable st udy on the bobwhite quail (upland game) is available (MRID 41670602), which demons trates effects to bobwhite on a sublethal basis. Data should also be submitted on a waterfowl species for guideline 850.2200 to test for differences in interspecies sensitivity to ancymi dol on a subacute dietary basis.

Under the 40 CFR Part 158 (July 1, 2009) data re quirements for conventional pesticides, avian reproduction data are required on waterfowl and upland game species (OCSPP Guideline 850.2300). Because no chronic data on birds have been submitted to date, EFED recommends requesting two avian reproduction st udies according to the data requirements for an outdoor use

chemical. EFED will assume risk to birds on a chronic basis in the absence of these data.

Acute and Chronic Freshwater Inverteb rate and Fish Toxicity Studies

Two acute freshwater fish (OCSPP Guideline 850 .1075) and one acute estuarine/marine fish are required for registration of pestic ides with outdoor uses (CFR Part 158). Both a cold and warm water species of freshwater fish are required for testing; to date, only data on the rainbow trout (MRID 41670603), a cold water species, is availabl e. The study on rainbow trout was conducted as a limit test with a resulting LD 50 of > 99.2 mg a.i./L. Clinical signs of toxicity exhibited by fish at this concentration were labored respiration, prostration, and a distended ventral surface. Due to these effects, and because of the uncerta inty in application rates and exposure levels,

adverse effects to listed freshw ater fish cannot currently be determined; however, because additional information labeled application rates ar e being requested in add ition to data on a warm water fish species, a second acute freshwater fish study with a cold water species is not requested

at this time. Acute data on fr eshwater invertebrates, estuarine/marine invertebrates, and estuarine/marine mollusks are also required for re gistration of pesticides with outdoor uses (CFR Part 158). Acceptable data on the freshwater invertebrate, Daphnia magna , have already been

submitted. Data should be submitted for the remain ing two acute fish (warm freshwater species and marine/estuarine species) and two acute invert ebrate toxicity studies (at least one mollusk and one as specified by the 850.1035 or 850.1045 guidelines ( i.e. a species of shrimp); in the absence of these data, EFED will presume risk to estuarine/marine fish and invertebrates on an acute exposure basis.

Chronic toxicity studies for ancymidol with freshw ater fish or invertebra tes are not available at this time and are required for registration of pest icides with outdoor uses (CFR Part 158). EFED

will assume risk to these taxa on a chronic basis in the absence of these data. Chronic toxicity studies for ancymidol with estuarine/marine fish or invertebrates are conditional requirements and are not triggered for ancymidol based on th e available ecotoxicity data, the anticipated environmentally relevant concentrations, and us e pattern criteria; based on this information,

chronic risk to estuarine/marine fish and invertebrates will be determined in the final risk assessment. EFED reserves the right to request chronic toxicity studies on these taxa in the

future once additional fate and eco toxicity data, as well as app lication information have been

-29 of 46-submitted. A freshwater invertebrate life cycle test (Guideline 850.1300) and a freshwater fish early life stage test (Guidelin e 850.1400) should be submitted.

Aquatic and Terrestrial Plant Toxicity Studies

Aquatic plant toxicity studies and associated risk analysis of plants ar e required for registration of pesticides with out door uses. For known phytotoxicants, such as plant growth regulators, a Tier II aquatic vascular pl ant toxicity study (OCSPP Guide line 850.4400) and four Tier II nonvascular plant toxicity studies (OCSPP Guid eline 850.5400) on either the TGAI or a TEP are required. The available Tier II vascular aquatic plant study with the TGAI using L. gibba , MRID 43140501, was reviewed and fully meets OCSPP Guide line standards. Like wise, the available Tier II freshwater green al ga toxicity study with the T GAI (MRID 43140502) is classified Acceptable. However, three more nonva scular plant studies are required, i.e ., freshwater diatom, saltwater diatom, and a nitrifying cyanobacteria . Because ancymidol is a known phytotoxicant, EFED recommends requesting three additional toxi city studies on nonvascular aquatic plants. Because of the ingredients typically co-formulate d with herbicides and plant growth regulators ( e.g. surfactants), EFED prefers that these studies are conduc ted on a representative TEP ( i.e. ABIDETM or A-Rest* Solution®). EFED will assume risk to aquatic nonvascular plants in the

absence of these data.

Terrestrial plant toxicity studies are required for regi stration of pesticides with outdoor uses (CFR Part 158). For known phytotoxicants, such as plant growth regulator s, Tier II vegetative vigor (OSCPP 850.4250) and Tier II seedling emer gence (OCSPP 850.4225) studies are required on a TEP ( i.e. ABIDETM or A-Rest* Solution®) to investig ate the effects of the pesticide end-use product on the growth and survival of terrestrial plants. No data is currently available for these guidelines and the extent of risk s to non-target (as well as target ) terrestrial plants cannot be determined. Risk to terrestrial plants is assumed in the absence of data.

-30 of 46-8. References

Hofmannova, Jana, Katerina Schwarzerova, Lenka Havelkova, Petra Borikova , Jan Petrasek, and Zdenek Opatrny, 2008. A novel, cellulose sy nthesis inhibitory action of ancymidol impairs plant cell expansion. Journal of Experimental Botany , Vol. 59, No.14:3963-3974.

ChemBlink. 2011. Online database of chemicals fr om around the world (ancymidol structure) Accessed on January 21, 2011. Online at: h ttp://www.chemblink.com/products/12771-

68-5.htm

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the EPA food-chain (Kenaga) nomogram, an instru ment for estimating pesticide residues on plants. Environ. Tox. Chem. 13 :1383-1391.

Hoerger, F. and E. E. Kenaga. 1972. Pe sticide Residues on Plants: Correlation of Representative Data as a Basis for Estimation of their Magnitude in the Environment. In F. Coulston and F. Korte, eds., Environmental Quality and Safety: Chemistry, Toxicology, and Technology, Georg Thieme Publ., Stuttgart, West Germany, pp. 9-28.

USEPA. 1995. Reregistration Eligibility Decision for Ancy midol: Division Director’s Concurrence Copy. U.S. Environmental Pr otection Agency, Office of Pesticide Programs. July 28, 1995.

USEPA. 1998. Guidelines for Ecological Risk A ssessment. Risk Assessment Forum, Office of Research and Development, Washi ngton, D.C. EPA/630/R-95/002F. April 1998. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. U.S. Environmental Protection Ag ency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004.

USEPA. 2007a. Ecological Incident Information System. http://www.epa.gov/espp/consultation/ecorisk-overview.pdf

USEPA. 2007 b . ECOTOXicology Database . Office of Research and Development National

Health and Environmental Effects Research Laboratory’s (NHEERL’s) Mid-Continent Ecology Division (MED). http://cfpub.epa.gov/ecotox/

.

USEPA. 2010. Ancymidol (108601): Screening Level Usage Analysis. U.S. Environmental Protection Agency, Office of Prevention, Pes ticides and Toxic Substances, Biological and Economic Analysis Division. Dec 01, 2010.

U.S. Fish and Wildlife Service (USFWS) and Na tional Marine Fisheries Service (NMFS). 1998. Endangered Species Consultation Handbook: Procedures for Conducting Consultation

and Conference Activities Under Section 7 of the Endangered Sp ecies Act. Final Draft.

March 1998.

-31 of 46-USFWS/NMFS/NOAA.2004. 50 CFR Part 402. Join t Counterpart Endangered Species Act Section 7 Consultation Regulations; Final Rule. Federal Register Volume 69. Number 20.Pages 47731-47762. August 5, 2004.

U.S. Geological Survey (USGS). 2010. Pesticide Use Maps. U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Program, Pe sticide National Synt hesis Program. Accessed on January 26, 2011. Online at: http://water.usgs.gov/nawqa/pnsp/ usage/maps/compound_listing.php?year=02

-32 of 46-SUBMITTED ENVIRONMENTAL FATE STUDIES:

MRID: Citation:

00162638 Day, E., 1986. Ancymidol Techincal Product chemistry Data: Report No. EWD8604. Unpublished study prepared by Lilly Research Laboratories.

41723501 Kazee, B. (1990) Determination of Sol ubility of Ancymidol: Final Report: Lab. Project Number: SC900027. Unpublished study prepared by Battelle.

41723502 Davis, M. (1990) Ancymidol: Adsorption/Desorption of Carbon 14 -Ancymidol on Soils by the Batch Equilibrium Method: Lab Project Number: SC900026. Unpublished study prepared by Battelle.

41723503 Kazee, B. (1990) Hydrolysis of Ancy midol in Water: Lab Project Number: SC900028. Unpublished study prepared by Battelle.

41821201 Chakrabarti, A. (1990) Vapor Pressure of Ancymidol Measured by the KnudsenEffusion/Weight Loss Method: La b Project Number: ML-AL- 90-020336. Unpublished study prepared by Dow Chem ical, Analytical Sciences Div.

41913701 Zwick, T., Saxena, A.; Marsh, S. (1991) Mobility Study: Soil Column Leaching Study on a Soil Dosed With 14C-Ancymi dol and Aged: LabProject Number: SC900025. Unpublished study prepared by Ba telle Memorial Institute.

42053001 Saxena, A., Malik, N., Lofthouse, T. (1991) Aerobic Soil Metabolism of Ancymidol: Lab Project Number: SC900021. Unpublished study prepared by

Battelle Memorial Institute.

SUBMITTED EFFECTS STUDIES:

MRID: Citation:

00162642 Kehr, C.C., D.S. Negilski, T.L. Bridge , and T.F. Markey, 1986. The Acute Oral, Dermal, Ocular, and Inhalation Toxicity of A-rest® Solution, a Formulation (FN7086) Containing 0.0264% Ancymidol. Study IDs: R-O-286-85, B-D-204-85, BE-207-85, and R-H-099-85. Toxicity Divisi on, Lilly Research Laboratories, Division of Eli Lilly and Co mpany, Greenfield, IL. 44 p.

41670601 Murray, A.; Seacat, J.; Brown, G. (1990) The Acute Toxicity of An- cymidol to Daphnia magna in a Static Test System: Lab Project Number: C00690. Unpublished study prepared by Lilly Research Laboratories. 35 p.

41670602 Murray, A.; Seacat, J.; Grothe, D. (1990) Th e Toxicity of Ancymi- dol to Juvenile Bobwhite in a 5-Day Dietary Study: Lab Project Number: A00790. Unpublished study prepared by Lilly Research Laboratories. 40 p.

-33 of 46-41670603 Murray, A.; Seacat, J.; Brown, G. (1990) The Acute Toxicity of An- cymidol to Rainbow Trout (Salmo gairdneri) in a St atic Test System: Lab Project Number: F02890. Unpublished study prepared by Lilly Research Laboratories. 38 p.

43140501 Milazzo, D.; Servinski, M.; Hugo, J.; et al. (1994) Ancymidol: Toxicity to the Aquatic Plant, Duckweed, Lemna gibba L: Lab Project Number: DECO/ES/2725. Unpublished study prepared by The Dow Chemical Environmental Toxicology & Chemistry Research Lab. 31 p.

43140502 Milazzo, D.; Servinski, M.; Hugo, J.; et al. (1994) Ancymidol: Toxicity to the Green Alga, Selenastrum capricornutum Printz: Lab Project Number: ES/2724. Unpublished study prepared by The Dow Chemical Environmental Toxicology & Chemistry Research Lab. 31 p.

43140504 Palmer, S.; Beavers, J. (1993) Ancymidol: An Acute Contact Toxicity Study with the Honey Bee: Lab Project Number: 103/402: ES/2687. Unpublished study prepared by Wildlife International Ltd. 21 p.

42480601 Wright, F.L., R.G. Poulsen, and R.L. St. Clair, 1992. The Acute Toxicity of Ancymidol (Compound 069231) Administered Orally to Fischer 344 Rats. Laboratory Project ID: R23391. Performe d by Lilly Research Laboratories, Division of Eli Lilly and Company, Gr eenfield, IN. Submitted by DowElanco, Indianapolis, IN. Study Completed August 31, 1992.

47331303 Farkas, Beáta, 2007. Acute Oral Toxici ty Study (Acute Toxic Class Method) of Test Item Ancymidol (0.0264% SL Formula tion in Rats. Test Performed by LAB International Research Centre Hungary Ltd. H-8200 Veszprém, Szabadságpuszta. Lab Study No: 07/395-001P. Study Sponsored by Fine Agrochemicals Ltd. Wocester, Worcestershire, UK.

-34 of 46-APPENDIX A: SIP v.1.0 Description, Assumptions, Inputs and Outputs

SIP v.1.0 provides an upper bound estimate of ex posure of birds and mammals to pesticides through drinking water alone. This model is intended for use in problem formulation to determine whether or not drinking water exposure alone is a po tential pathway of concern. This does not aggregate drinking water exposure with other exposure routes (i.e., diet, inhalation, dermal).

Assumptions:

SIP employs the following conservative assumptions to derive upper bound exposure

estimates:
1) The chemical concentration in drinking wate r is at the solubility limit in water (at 25 o C).
2) The assessed animals obtain 100% of thei r daily water needs through drinking water. 3) The daily water need is equivalent to the da ily water flux rate as calculated by Nagy and Peterson (1988). 4) The body weight of the assessed bird is equiva lent to the smallest generic bird modeled in T-REX (i.e., 20 g). This assumpti on results in the highest ratio of exposure to toxicity for the 3 assessed avian body weights of T-REX (i.e., 20, 100, 1000 g).

5) The body weight of the assessed mammal is equivalent to the largest generic mammal modeled in T-REX (i.e., 1000 g). This results in the highest ratio of exposure to toxicity for the 3 assessed mammalian body weights of T-REX (i.e., 15, 35, 1000 g).

Table 1. Inputs

Parameter Value

Chemical name Ancymidol

Solubility (in water at 25 o C; mg/L) 650

Mammalian LD 50 (mg/kg-bw) 1016
Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 0
Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg-bw) 0
Avian test species mallard duck Body weight (g) of "other" avian species
Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 0 Bobwhite quail NOAEC (mg/kg-diet) 0 NOAEC (mg/kg-diet) for other bird species 0 Body weight (g) of other avian species 0 NOAEC (mg/kg-diet) for 2nd other bird species 0 Body weight (g) of 2nd other avian species 0

-35 of 46-Table 2. Mammalian Results

Parameter Acute Chronic
Upper bound exposure (mg/kg-bw) 111.8000 111.8000 Adjusted toxicity value (mg/kg-bw) 781.4671 0.0000 Ratio of exposure to toxicity 0.1431 0.0000

Conclusion* Exposure through drinking water alone is a potential concern

for mammals Due to insufficient data, risk cannot be precluded

Table 3. Avian Results

Parameter Acute Chronic
Upper bound exposure (mg/kg-bw) 526.5000 526.5000 Adjusted toxicity value (mg/kg-bw) 0.0000 0.0000 Ratio of exposure to acute toxicity 0.0000 0.0000

Conclusion* Due to insufficient data, risk cannot be precluded Due to insufficient data, risk cannot be precluded

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non-target animals.

-36 of 46-APPENDIX B: Data Call-In Tables

The Environmental Fate and Effects Division (EFE D) has completed a Data Call-In (DCI) table for the ancymidol environmental fate and effects data gaps identified in Registration Review. The attached DCI table, which includes the gu ideline number and study t itle for required data, also provides a rationale for requi ring the data, an explanation of how the data will be used, and a brief description of how the data could im pact the Agency’s future decision-making.

Guideline Number: 835.2240 Study Title: Photodegradation in water
Rationale for Requiring the Data Acceptable data on the photodegradation in water of ancymidol are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Currently, there are no submitted studies that satisfy the guideline. Theref ore, the Agency has a li mited understanding of the how ancymidol behaves in aquatic environments in presence of light. Photodegradation studies determine the potential to degradate in when exposed to sunlight. During these studies, data are also collected concerning the identity, formation and persistence of major degradates. Depending on how quickly, to what extent, and to which transformation products the compound degrades, ancymidol may or may not pose a potential for surface water contaminat ion. Because photodegradation of ancymidol in water is not well understood, the Agency is requiri ng an OCSPP guideline-compliant photodegradation in water study. Practical Utility of the Data

How will the data be used? Photolytic degradation data will facilitate a better understanding of th e fate of ancymidol residues in aquatic environment. If data indicate that degrad ation in water occurs ra pidly and produces nontoxic transformation products, then the Agency could poten tially determine that ancymidol residues of concern do not persist in aquatic systems. If data indicate that degradation is not appreciable in aquatic systems or that the transformation products are of similar or higher toxicity than the parent compound, then the Agency could conclude that ancymidol residu es of concern persist in aquatic systems.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? In the absence of the requested data, ancymidol phot olytic degradation half-lives will be conservatively assumed stable. If the required data indicate that ancy midol is rapidly degrade in presence of sunlight to nontoxic degradation products, then risk assessment conclusions and associated labeled use precautions

and/or restrictions could be made less restrictive.

Guideline Number: 835.2410 Study Title: Photodegradation in soil
Rationale for Requiring the Data Acceptable data on the photodegradation in soil of ancymidol are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Currently, there are no submitted studies that satisfy the guideline. Theref ore, the Agency has a li mited understanding of the how ancymidol behaves in soil in presence of sun light. This study provi des data on photolytic degradation and on nature and persistence of photoproducts formed on soil surface through photolysis. During these studies, data are also collected concerni ng the identity, formation and persistence of major degradates. Depending on how quickly, to what extent, and to which transformation products the compound degrades, ancymidol may or may not pos e a potential exposure on soil surface. Because

-37 of 46-photo-degradation of ancymidol in soil is not we ll understood, the Agency is requiring an OCSPP guidelinecompliant photodegradation in soil study. Practical Utility of the Data

How will the data be used? Photolytic degradation data will f acilitate a better understanding of the fa te of ancymidol residues in soil surface. If data indicate that degradation in soil surface occurs rapidly and produces nontoxic transformation products, then the Agency could poten tially determine that ancymidol residues of concern do not persist in soil surface. If data indicate that degr adation is not appreciable in soil surface or that the transformation products are of similar or higher to xicity than the parent compound, then the Agency could conclude that ancymidol residues of c oncern persist in terrestrial environment.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? In the absence of the requested data, ancymidol phot olytic degradation half-lives will be conservatively assumed stable. If the required data indicate that ancy midol is rapidly degrade in presence of sunlight to nontoxic degradation products, then risk assessment conclusions and associated labeled use precautions

and/or restrictions could be made less restrictive.

Guideline Number: 835.4100 Study Title: Aerobic Soil Metabolism
Rationale for Requiring the Data Four acceptable data on the aerobic soil metabolism of ancymidol are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Currently, one submitted studies that satisfy the guideline to evaluate the rate of transformation of ancymidol in soil. Therefore, the Agency has a limited understanding of how ancymidol behaves in aerobic soil environments once applied. Because ancymidol degradation in aerobic so il systems is not fully understood, the Agency is requiring an OCSPP guideline-compliant additional aerobic soil metabolism studies. Practical Utility of the Data

How will the data be used?

Additional aerobic soil metabolism data will facilitate a better understanding of the fate of ancymidol residues in soil. If data indicate that degradation in aerobic conditions occu rs rapidly and produces nontoxic transformation products, then the Agency could potentially determine that ancymidol residues of concern do not persist in these systems. If data indicate that degradation is not appreciable in aerobic soil systems or that the transformation products are of similar or higher toxicity than the parent compound, then the Agency could conclude that an cymidol residues of concern persist in aerobic soil

systems.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? In the absence of the requested additional data, currently available aerobic soil metabolism half-live for ancymidol will be multiplied by to reduce uncertainty . If the required data indicate that ancymidol in aerobic soil environments is rapidly biodegraded to nontoxic degradation products, then risk assessment conclusions and associated labeled use precautions and/ or restrictions could be made less restrictive.

Guideline Number: 835.4200 Study Title: Anaerobic Soil Metabolism
Rationale for Requiring the Data Acceptable data on the anaerobic soil metabolism of ancymidol are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Currently, there are no submitted studies that satisfy the guideline. Theref ore, the Agency has a li mited understanding of how ancymidol behaves in anaerobic soil environments once applied. Depending on how quickly, to what

-38 of 46-extent, and to which transformation products the compound degrades, ancymidol may or may not pose a potential for ground water contamination. Because an cymidol degradation in anaerobic soil systems is not well understood, the Agency is requiring an OCSPP guideline-compliant anaerobic soil metabolism study. Practical Utility of the Data

How will the data be used?

Anaerobic soil metabolism data will facilitate a better understanding of the fate of ancymidol residues in subsurface soil, and anaerobic sediments. If data indica te that degradation in anaerobic conditions occurs rapidly and produces nontoxic transformation products, th en the Agency could potentially determine that ancymidol residues of concern do not persist in these systems. If data indicate that degradation is not appreciable in anaerobic systems or that the transforma tion products are of similar or higher toxicity than the parent compound, then the Agency could conclude that ancymidol residues of concern persist in anaerobic soil systems.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? In the absence of the requested data, ancymi dol anaerobic soil metabolism half-lives will be conservatively assumed stable. If the required data indicate that ancymidol in anaerobic soil environments is rapidly biodegraded to nontoxic de gradation products, then risk assessment conclusions and associated labeled use precautions and/or r estrictions could be made less restrictive.

Guideline Number: 835.4300 Study Title: Aerobic Aquatic Metabolism
Rationale for Requiring the Data Acceptable data on the aerobic aquatic metabolism of ancymidol in two sediment systems are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. No aerobic aquatic metabolism study was submitted. Th e Agency has a limited understanding of how ancymidol behaves in aerobic aquatic environments once applied. Data are needed for two sedimentwater systems conducted (one each) at neutral and acidic pHs. Practical Utility of the Data

How will the data be used? Aerobic aquatic metabolism data will facilitate a better understanding of the fate of ancymidol residues in water. If data indicate that degradation in aerobic co nditions occurs rapidly in neutral and acidic aquatic systems and produces nontoxic transformation products, then the Agency could pot entially determine that ancymidol residues of concern do not persist in these systems. If data indicate that degradation is not appreciable in aquatic systems or that the transformati on products are of similar or higher toxicity than the parent compound, then the Agency could conclude that ancymidol residues of concern persist in acidic aquatic systems under anaerobic conditions.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? In the absence of the requested data, ancymidol aerobic aquatic metabolism half-lives will be conservatively assumed to be stable at a neutral pH, or less conservatively at two times the aerobic soil metabolism half-life modeling input value. If the requ ired data indicate that ancymidol in aerobic aquatic environments is rapidly biodegraded to nontoxic de gradation products, then risk assessment conclusions and associated labeled use precautions and/or restrictions could be made less restrictive.

-39 of 46-Guideline Number: 835.4400 Study Title: Anaerobic Aquatic Metabolism
Rationale for Requiring the Data Acceptable data on the anaerobic aquatic metabolism of ancymidol are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Currently, there are no submitted studies that satisfy the guideline. The Agency has a limited understanding of how ancymidol behaves in anaerobic aquatic environments once a pplied. Thus, the Agency is requiring an OCSPP guideline-compliant anaerobic aquatic metabolism study with two systems, one each at a neutral pH and one at an acidic pH. Practical Utility of the Data

How will the data be used? Anaerobic aquatic metabolism data w ill facilitate a better understanding of the fate of ancymidol residues in water. If data indicate that degradation in anaerob ic conditions occurs rapidly in acidic and/or neutral aquatic systems and produces nontoxic transformation products, then the Agency could potentially determine that ancymidol residues of concern do not persist in these systems. If data indicate that degradation is not appreciable in aquatic systems or that the transformation products are of similar or higher toxicity than the parent compound, then the Agency could conclude that ancymidol residues of concern persist in acidic aquatic systems under anaerobic conditions.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? In the absence of the requested data, ancymidol anaerobic aquatic metabolism half-lives will be conservatively assumed to be stable at a neutral pH If the required data indicate that ancymidol in anaerobic aquatic environments is rapidly biodegra ded to nontoxic degradation products, then risk assessment conclusions and associated labeled use pr ecautions and/or restrictions could be made less

restrictive.

Guideline Number: 850.2100 Study Title: Avian Acute Oral Toxicity Test Rationale for Requiring the Data Acceptable avian acute oral toxicity data were not submitted for exposures of either bobwhite quail or mallard ducks to ancymidol; additio nally, data are not available for a passerine species, which is now required under the 40 CFR Part 158 (Oct. 26, 2007) da ta requirements for conventional pesticides. The new Part 158 data requirements specify that acute avian oral toxicity data be submitted for either mallard duck or bobwhite quail and a passerine species. Therefor e, an avian oral toxicity test is required for either mallard duck or bobwhite quail and a passerine species, as specified in 40 CFR Part 158. A passerine study protocol must be submitted for review by the Agency prior to initiation of this study. Practical Utility of the Data

How will the data be used? Avian acute oral toxicity data will be used to dete rmine the lethal dose of ancymidol to birds on a body weight basis. Acute oral toxicity information accounts for eating differences among birds, which cannot

be estimated based on the available subacute dietar y data for ancymidol. Additionally, data on avian species in two different taxa will determine whether there are differences in sensitivity to ancymidol between passerines and upland game or waterfowl species. If oral acute toxicity data are not submitted, risk will be assumed for all avian species.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed birds di rectly (and listed species from other taxa indirectly), and use of ancymidol and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for

-40 of 46-ancymidol use that are unnecessarily severe.

Guideline Number: 850.2200 Study Title: Avian Subacute Dietary Toxicity Test Rationale for Requiring the Data Acceptable avian subacute dietary toxicity data were submitted for exposures of bobwhite quail to ancymidol; no data are available for exposures of ma llard duck to ancymidol. Based on the results of the available bobwhite quail study, the LC 50 > 5192 mg a.i/kg diet and the NOAEC = 2638 mg a.i/kg diet due to reductions in body weight. A second subacute diet ary study on mallard duck is required for pesticides with outdoor uses, as specified in 40 CFR Part 158. Practical Utility of the Data

How will the data be used? Avian subacute dietary toxicity data for mallard duck will be used to refine the screening-level assessment by determining whether there are diffe rences in avian species sensitivity to ancymidol between upland game and waterfowl species. If subacute dietary toxicity data are not submitted, risk will be assumed for certain avian species.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed birds di rectly (and listed species from other taxa indirectly), and use of ancymidol and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for ancymidol use that are unnecessarily severe.

Guideline Number: 850.2300 Study Title: Avian Reproduction Test Rationale for Requiring the Data Under the 40 CFR Part 158 (July 1, 2009) data requirements for conventional pesticides, avian reproduction data are required on wa terfowl and upland game species (O CSPP Guideline 850.2300). No data are available to assess chronic or reproductive eff ects of ancymidol exposure to any species of bird.

Based on the results of the availabl e bobwhite quail dietary study, the LC 50 > 5192 mg a.i/kg diet and the NOAEC = 2638 mg a.i/kg diet due to reductions in body weight. These sublethal effects suggest that birds may be sensitive to ancymidol on a reproductiv e or chronic basis. Therefore, two avian onegeneration reproduction studies of bobwhite quail and mallard duck are recommended. Practical Utility of the Data

How will the data be used? Due to lack of data, chronic risk to birds ha s not been quantitatively assessed. Neither has chronic risk to mammals, which may have provided inferences into potenti al chronic effects in

birds. The avian reproduction studies are needed to a llow the Agency to quantify the potential for chronic risk, as measured by effects on reproduction a nd hatchling survival, from the use of ancymidol. Without this data, chronic risk to birds will be assumed for outdoor ancymidol uses.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed birds, reptiles, and terrestrial-phase amphibians directly (and listed species from other taxa indirectly), and u se of ancymidol and its formulated products may

-41 of 46-need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act

and could result in use restrictions for ancymidol use that are unnecessarily severe.

Guideline Number: 850.1025 Study Title: Estuarine/marine Mollusk (Oyster)Acute Toxicity Test (Shell Deposition)

or Guideline Number: 850.1055 Study Title: Bivalve acute (embryo-larval) EC 50 Rationale for Requiring the Data The CFR Part 158 data requirements specify that acute toxicity data on estuarine/marine mollusks are required for the registration of pesticides with outdoor uses. Scientifically valid acute toxicity data are

not available for this taxon. Either an acute estuarine/marine oyster (OCSPP 850.1025) or estuarine/marine bivalve (OCSPP 850.1055) toxici ty test is requested at this time. Practical Utility of the Data

How will the data be used? Acute freshwater invertebrate toxicity data will be used to determine the potential for ancymidol to affect mollusk and other invertebrate species in saltwater environments. Marine/estuarine invertebrates are likely to be exposed to ancymidol because of its use in nurseries. The data will inform the current risk

assessment for estuarine/marine invertebrates and will improve the Agency’s understanding of the potential effects of ancymidol on aquatic animals. In the absence of data specific for these invertebrates, risk to freshwater invertebrates will be presumed.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed fresh water invertebrates directly (and listed species from other taxa indirectly), and use of ancymidol and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for ancymidol use that are unnecessarily severe.

Guideline Number: 850.1035 Study Title: Mysid Acute Toxicity Test

or Guideline Number: 850.1045 Study Title: Penaeid Acute Toxicity Test Rationale for Requiring the Data Under the 40 CFR Part 158 (July 1, 2009), data are re quired on an estuarine/marine invertebrate other than a mollusk for pesticides with outdoor uses. The data will inform the current risk assessment for estuarine/marine invertebrates and will improve the Agency’s understanding of the potential effects of ancymidol on aquatic animals. As a result, one fr eshwater invertebrate life-cycle study on mysid or penaeid shrimp, OCSPP 850.1035 or 8501045, respectively, is require d to support all outdoor use

patterns. Practical Utility of the Data

How will the data be used? The data would allow the Agency to quantify the potential for risk to saltwater invertebrates. Marine/estuarine invertebrates are likely to be expo sed to ancymidol because of its use in nurseries. Because of the lack of marine/estuarine toxicity data, the Agency is unable to definitively determine whether ancymidol exposure will pose a risk to aquati c invertebrates inhabiting marine/estuarine water bodies. In the absence of data specific for these invert ebrates, risk to freshwater invertebrates will be

-42 of 46-presumed.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed fresh water invertebrates directly (and listed species from other taxa indirectly), and use of ancymidol and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for ancymidol use that are unnecessarily severe.

Guideline Number: 850.1075 Study Title: Fish Acute Toxicity Test, Freshwater Rationale for Requiring the Data Acceptable freshwater fish acute toxicity data we re submitted for exposures of rainbow trout, a cold water species, to ancymidol; data were not subm itted for a warm water species, required under the 40 CFR Part 158 (July 1, 2009) data requirements for conve ntional pesticides. The available data show that

test fish exhibited sublethal effects at the lim it dose. A second dose-response study on a warm water species should be submitted to the Agency under OCSPP Guideline 850.1075. Practical Utility of the Data

How will the data be used? Acute freshwater fish toxicity data with a warm water species will be used to refine the screening-level assessment by determining whether there are differences in fish species sensitivity to ancymidol. If acute toxicity data are not submitted, risk may be assumed for listed freshwater fish species.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed fresh water invertebrates directly (and listed species from other taxa indirectly), and use of ancymidol and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for ancymidol use that are unnecessarily severe.

Guideline Number: 850.1075 Study Title: Fish Acute Toxicity Test, Estuarine/Marine Rationale for Requiring the Data The CFR Part 158 data requirements specify that acute toxicity data on estuarine/marine fish are required for the registration of pesticides with outdoor uses. No data has been submitted on the acute exposure of ancymidol to estuarine/marine fish. A fish acute toxicity test under OCSPP Guideline 850.1075 with an estuarine/marine fish species is requested at this time. Practical Utility of the Data

How will the data be used? The data would allow the Agency to quantify the potential for risk to saltwater fish. Marine/estuarine fish are likely to be exposed to ancymidol because of its use in nurseries. Because of the lack of marine/estuarine toxicity data, the Agency is un able to definitively determine whether ancymidol exposure will pose a risk to fish inhabiting marine/estuarine water bodies. In the absence of data specific for this taxon, risk to estuarine/marine fish will be presumed.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that ancymidol “may affect” listed fresh water invertebrates directly (and listed species from

-43 of 46-other taxa indirectly), and use of ancymidol and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for ancymidol use that are unnecessarily severe.

Guideline Number: 850.4225 Study Title: Terrestrial Plant Seedling Emergence Test (Tier II) Rationale for Requiring the Data Terrestrial plant toxicity studies are required for re gistration of pesticides with outdoor uses (CFR Part 158). For known phytotoxicants, a Tier II seedling em ergence study (OCSPP 850.4225) is required on a

TEP ( i.e. ABIDETM or A-Rest* Solution®) to investigate the effects of the pesticide end-use product on the emergence, growth, and survival of terrestrial plants. No data is currently available for this guideline and the extent of risk s to non-target terrestrial pl ants cannot be determined.
Practical Utility of the Data

How will the data be used? Tier II seedling emergence data for terrestrial plants will be used to determine the potential for ancymidol to affect non-target plant species in the terrestrial environment and to reduce uncertainties associated with the current risk assessment to terrestrial plants. In the absence of data specific to the emergence and initial growth life stages, the spatial extent of risk to terrestrial plants off the application site cannot be

determined.

How could the data impact the Agency’s future decision-making? Because plants form the basis of most habitats and significantly contribute to overall environmental quality, a solid understanding of the potential risks to terrestrial plants is essential for sound environmental management. If the data indicate that registered ancymidol usage poses an even greater risk of adverse effects to non-target terrestrial plan ts above the Agency Level of Concern, the Agency may further explore decision options to mitigate this risk . The lack of data on the spatial extent of risk will limit the flexibility the Agency and registrants ha ve in coming into compliance with the Endangered Species Act.

Guideline Number: 850.4250 Study Title: Terrestrial Plant Vegetative Vigor Test (Tier II) Rationale for Requiring the Data Terrestrial plant toxicity studies and associated risk analysis of plants are required for registration of pesticides with outdoor uses (CFR Part 158). For know n phytotoxicants, a Tier II vegetative vigor study (OSCPP 850.4250) is required on a TEP ( i.e. ABIDETM or A-Rest* Solution®) to investigate the effects of the pesticide end-use product on the growth and survival of terrestrial plants. No data is currently available for this guideline and the extent of risk of spray drift to non-target terrestrial plants cannot be determined.

-44 of 46-Practical Utility of the Data

How will the data be used? Tier II vegetative vigor data for terrestrial plants w ill be used to determine the potential for ancymidol to affect non-target plant species in the terrestrial e nvironment and to reduce uncertainties associated with the current risk assessment to terrestrial plants. In the absence of data specific to the emergence and initial growth life stages, the spatial extent of risk to terrestrial plants off the application site cannot be

determined.

How could the data impact the Agency’s future decision-making? Because plants form the basis of most habitats and significantly contribute to overall environmental quality, a solid understanding of the potential risks to terrestrial plants is essential for sound environmental management. If the data indicates that registered ancymidol usage poses an even greater risk of adverse effects to non-target terrestrial plan ts above the Agency Level of Concern, the Agency may further explore decision options to mitigate this risk . The lack of data on the spatial extent of risk will limit the flexibility the Agency and registrants ha ve in coming into compliance with the Endangered Species Act.

Guideline Number: 850.5400 Algal Toxicity Tier II Study Rationale for Requiring the Data Aquatic (both vascular and non-vascular species) toxicity studies and associated risk analysis of plants are required for registration of pesticides with outdoor uses (CFR Part 158). For known phytotoxicants,

four Tier II nonvascular toxicity studies (OCSPP Guidelin e 850.5400) on either the TGAI or TEP are required. There is currently only one available stud y on freshwater green algae for the TGAI to determine levels of ancymidol that could result in effects to aquatic non-vascular plants. Three more nonvascular plant studies are required as specified in 40 CFR Part 158; these include a study on a freshwater diatom, saltwater diatom, and nitrifying cyanobacteria. Because of potential changes in novaluron’s bio-availability in water while formulat ed as an end-use product, EFED prefers these studies be conducted with a representative TEP ( i.e. ABIDETM or A-Rest* Solution®) instead of the TGAI.
Practical Utility of the Data

How will the data be used? This Tier II data will be used to adequately assess risks to aquatic nonvascular plants from ancymidol exposure. The data will reduce uncertainties associat ed with the current risk assessment for aquatic nonvascular plants based currently on only one species and will improve our understanding of the potential effects of ancymidol use to aquatic plants. In the absence of data specific to freshwater diatoms, saltwater diatoms, and a nitrifying cyanobacteria, the extent of effects to nonvascular plants would be unknown and the extent of risk to aquatic plants could potentially be underestimated. Because plants form the basis of most habitats and significantly contribute to overall environmental quality, a solid understanding of the potential risks to aquatic plants is essential for sound environmental management. As a known phytotoxicant, risk to aquatic plants from ancymidol use would be presumed in the absence

of these data. The data will also be used in dete rmining whether a “may affect” to Federally-listed threatened and endangered species is likely under the Endangered Species Act.

How could the data impact the Agency’s future decision-making? Without additional nonvascular aquatic plant toxicity data for ancymidol, the Agency cannot determine

-45 of 46--46 of 46- with certitude the levels of ancymidol that result in effects to nonvascular aquatic plants. If this data is not available, the extent of risk to aquatic nonvascu lar plants from ancymidol use could potentially be underestimated. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in severe use restrictions for ancymidol, a known phytotoxicant, which may otherwise be avoided.