### Officeof Pmntion, Pesticides, and Toxic Substances



# Environmental Fate and Ecological Risk Assessment for the Registration of Florasulam

Florasulam CAS No. 145701-23-1 PC Code 129108

### I. Executive Summary A. Nature of the Chemical Stressor 

### B. Conclusions -Exposure Characterization C. Conclusions -Effects Characterization D. Potential Risks to Non-target Organisms E. Data Gaps and Uncertainties 11. Problem Formulation A. Previous Assessments 

### B. Stressor Source and Distribution 1. Source and Intensity 2. Physical/Chemical/Fate and Transport Properties 

### 3. Pesticide Type, Class, and Mode of Action 4. Usage Overview 

### B. Receptors C. Assessment Endpoints 

### D. Conceptual Model 1.Diagram 2. Risk Hypothesis E. Analysis Plan 11. Analysis A. Use Characterization 

### B. Exposure Characterization 1. Environmental Fate and Transport Characterization 

### 2. Aquatic Exposure 

### 3. Terrestrial Exposure C. Ecological Effects Characterization 1. Aquatic Effects 2. Terrestrial Effects 

### 3. ECOTOX 111. Risk Characterization 

### A. Risk Estimation 1. Aquatic Species 

### 2. Terrestrial 

### B. Risk Description 1. Aquatic 2. Terrestrial C. Uncertainties and Data Gaps IV. Conclusion V. Threatened and Endangered Species A. Action Area B. Taxonomic Groups Potentially at Risk C. Indirect Effects Analysis 

### D. Critical Habitat E. Co-occurrence Analysis VI. References

### I, EXECUTIVE SUMMARY
A. 

### Nature of the Chemical Stressor The Environmental Fate and Effects Division (EFED)has reviewed the proposed use of florasulam as an herbicide for the postemergent control of broadleafweeds in wheat, barley, rye and triticale crops. Florasulam, a sulfonamideALS inhibitor,isproposed for Section 

### 3 registration in the United States (U.S.) as an active ingredient in four formulated products. The proposed labels allow application as an aerial or ground spray at a maximum rate of 0.0045 lb ai/A. Florasulam was registered in Canada in 2001 and this assessmentdraws considerable support from Health Canada's Pesticide Management RegulatoryAgency (PMRA) Product Monograph and data evaluation records. However, all fate and toxicity studieswere reviewed and classified by EPA scientists for this assessment. 

### B. Conclusions 

### -Exposure Characterization Florasulam (XDE-570) is a very mobile compound that is not persistent in aerobic soil, rapidly degrading to the major degradate5-OH-XDE-570, which is in turn more slowly biodegraded to other degradates and eventually to C02and bound residues. Florasulam is not significantly degraded by abiotic processes. It readily degradesin aquatic systems, where it is biotransformed to 5-OH-XDE-570, which is then slowly furtherbiotransformed in some aerobic systems, but stable in other aerobic systems and in anaerobic systems. The degradate 5-OH-XDE-570 is more mobile in soil than the parent compound. Persistence or accumulation of the parent compound is not expected in the field based on laboratory soil studies and terrestrial field dissipation studies. The persistence and accumulation of 5-OH-XDE-570 ismore variable than that ofthe parent, indicating it may persist at some sites, but not others. Submitted data indicatethat the parent compound has a very low potential to bioaccumulate in aquatic organisms.
There is a potential for florasularn to reach surfacewater through spray drift and for both the parent compound and 5-OH-XDE-570 to reach surfacewater through runoff or subsurface flow, although this will be somewhat decreased for the parent due to its rapid biodegradationin aerobic soil. For 5-OH-XDE-570, the potential to reach surfacewater through runoffis greater than for the parent due to its slower biotransformationin aerobic soil and higher water solubility. For both compounds, the potential to reach surfacewater through runoff will be reduced by any leaching that occurs in the field. Based on the results of laboratoryand field studies, in which leachingwas observed, both florasulam and 5-OH-XDE-570 have the potential to leach to groundwater. However, for the parent, the potential to leach downward and to reach groundwaterwill be somewhat reduced by the fairlyrapid biotransformationofthe parent in aerobic soil. For 5-OH-XDE-570, the potential to leach is greater than that of the parent due to its slower biotransformationin aerobic soil and higher water solubility. For either compound, both ofwhich partition mainly to the water phase, the potential to leach will be greaterwhen there is excessiverainfall or irrigation, particularly if either of these occur close to the time of application. These concerns have alsobeen identified in the Canadian and 

### EU risk assessments for florasulam. 

### C. Conclusions -

### Effects Characterization Based on the data submitted in support of registration,florasularn is considered practically 3 of 44

### nontoxic on an acute exposure basis to aquatic and terrestrial wildlife. There was 40%, 60% and 100% mortality at the three highest (810, 1350and 2250 mg aikg)treatment levels in the avian acute oral study. There were no mortalities at the 175,292or 486 

### mgkgtreatment levels, but sublethal effects were noted at all but the lowest dose tested. No effects were observed in the avian subacute dietary or avian reproduction studies. No effectswere reported in the acute rat study. Sublethal effects on weight gain were observed in the two-generation rat reproduction study at the highest treatment level. Some mortality (<20%) was observed in the contact and oral bee studies at 100pglbee. No adverse effects attributable to florasulam were observed in acute and chronic studies with fish and aquatic invertebrates. As expected with an herbicide, effects were observed in both aquatic and terrestrialplant studies. The major degradate, 5-OH-XDE-570, is classified as practically nontoxic to aquatic invertebrates and fish based on submitted studies. 5-OH-XDE-570is considered not toxic to earthwormsup to 1120 mg ai/kg soil, and is less toxic to aquatic nonvascular plants (by several orders of magnitude) than the parent florasulam. The toxicity of 5-OH-XDE-570 to aquatic vascular and terrestrial plants is uncertain. A 

### 48-hr study of the toxicity of other degradates revealed no adverse effects to daphnids. D. Potential Risks to Non-target Organisms 

### Based on this screening-level assessment, the use of florasulam accordingto label direction should not result in direct acute or chronic effectsto aquatic or terrestrial wildlife. Based on the submitted guideline studies, the RQs for direct effectsto aquatic vascular and nonvascular plants are also below the level of concern (LOC). Adverse effectson sensitive terrestrialplant species cannot be precluded at distances of greater than 900 feet from the edge of field. Indirect effects to terrestrial or aquatic wildlife cannot be ruled out due to the potential for florasulam to effect changes in plant populations which may lead to changes in food supply or habitat. Table 1 

### summarizes the listed taxa potentially at risk from direct andlorindirect effects due to the use of florasulam on cereal grains.Table 1. Listed species risks associated with potential direct or indirect effects from the proposed use of florasulam on cereal grains.
Listed Taxon

Terrestrial and semi-aquatic Yes 

# I plants - dicots Terrestrial and semi-aquatic plants - monocots Direct Effects Acute

Yes

Insects

Birds Direct Effects Chronic yes'

Terrestrial-phase amphibians 

# I No Indirect Effects

No

NO

Reptiles

Mammals Aquatic plants No

Freshwater fish Aquatic-phase amphibians

Freshwater invertebrates

E. Data Gaps and Uncertainties No yes'

No

No

No

Mollusks

Marinelestuarine fish

Marinelestuarinecrustaceans

The environmental fate database is nearly complete and constitutes a strong point in this assessment, as both the degradation (type and rate) and mobility of the pesticide have been well established. Acceptable studies have been submitted for hydrolysis, photolysis (aqueous and on soil), aquatic metabolism (anaerobic and aerobic), mobility in soil, and terrestrial field dissipation (one site). Although multiple aerobic soil metabolism studies were submitted, each was classified "supplemental" (with the exception of one classified "not acceptable"). The single aerobic soil metabolism study conductedwith U.S. soils was classified "not acceptable"; none ofthe supplemental studies were conducted with U.S. soils. Because the parent degrades fairly rapidly, additional data for use in determining the half-life ofthe parent would not substantially decrease the 5 of 44 yes' yes1

No

NO

No No

No



### onli listed LOC is exceeded for terrestrial plants, thereforethere is potential for adverse effects to those species that rely either on a specificplant species or multiple plant species. Indirect effectsmay include general habitat modification, host plant loss, and food supply disruption. No

No

No - yes' yes' yes'

No

No

No yes1 yes' yes'

No

No

No yes1 yes1 yes'uncertainty associated with the exposure assessment. However, additional aerobic soil metabolism data would add to the available information on the degradates, as the submitted studies were incomplete in that respect. Terrestrial field dissipation data were submitted from only one 

### U.S. site. Although data for multiple foreign field sites were submitted, those studies were classified "supplemental" partially because the depth of sampling was insufficient to show the extent ofleaching that may occur in the field for both theparent and 5-OH-XDE-570. For cereal grains use, which covers a wide geographic area, data from additional 

### U.S. sites would decrease the uncertainty inherent in using data from a single location to determine terrestrial dissipation rates. The ecological effects database is largely complete and the effects on guideline taxa of exposure to the active ingredient the pesticide have been established. Additional data regarding degradates and formulation toxicity have been submitted and reviewed.
The seedling emergence study was highly variable in sometest species which likely contributed to a lack of statistical power. While there was no statistically significant effect greater than 25% on the emergence, shoot length orbiomass of any ofthe species tested in the seedling emergence study, several species (carrot, onion, soybean, cucumber, tomato) exhibited inhibitions ranging from 5%to 26% at rates as low as 0.00001 lbs ai/A. For example, at 0.00001 lbs ai/A (the lowest dose tested), tomatoes exhibited a mean 26% reduction in biomass relative to the control, but at 0.0029 lbs ai/A, a mean 5% increase in biomass relative to the control was observed. The replicate coefficients of variance (CV) for the treatments ranged from 12.4%to 80.5%, while the control CV was 

### 3.4%. The variability in this study is a source of uncertainty in this assessment, but is not thought to appreciably affect the risk conclusions.
This assessment assumes one growing season per year, based on common agricultural practices. However, the number of growing seasons per year is not limited by the label; areas with multiple growing seasons could result in greater exposures on an annual basis. Given that the parent is short-lived, the application rate is low, only one application is needed per season, and that the label has crop rotation restrictions, there may be herbicidal activity for longer than is suggested by fateproperties ofthe parent alone. The toxicity of the degradates to vascular plants is uncertain.



### 11. PROBLEM FORMULATION
A. Previous Assessments Florasulam has not previously been assessed for use in the United States by OPP. Although both fate and toxicity studies were reviewed and classified by EPA scientists, EPA, under a workshare agreement with Health Canada's Pesticide Management Regulatory Agency (PMRA), draws support from a previous environmental risk assessment by PMRA conducted in support of the registration of florasulam in Canada (Product Monograph, June, 2001). Overall risk conclusions are the same; any differences between the two risk assessments are based primarily on differing methods for estimating exposure and risk.

### B. StressorSource and Distribution


### 1. Source and Intensity This document evaluates the environmental fate and the potential ecological risk fkom the proposed use of florasulam for the postemergent control of broadleafweeds in wheat, barley, oat, rye and triticale crops. Application methods include both aerial and ground spray, at a maximum rate of 0.0045 lb ai/A. Because this would be the first time florasularn isregistered for use in the U.S.,the potential extent of use is not known. However, given the widespread distribution of areas that grow cereal grains, a nationwideuse is assumed. 

### 2. PhysicaUChernicaUFateand Transport Properties Florasulam (XDE-570) is a very mobile compound (all measured Kdsare <I) that is not persistent in aerobic soil, with laboratory half-lives of 0.7-8.3 days. It is stable to hydrolysis except at alkaline pHs, where it hydrolyzes slowly (half-life of 

### 99 days). Florasulam photodegrades slowly in water (half-life of 46 days), but is stable to photodegradation on soil. In aquatic environments, florasulam degrades readily (half-lives of 3-1

### 8 days in aerobic systemsand 2-13 days in anaerobic systems). In aquatic systems, florasulamis biotransformed to the major degradate 5-OH-XDE-570, which is then slowly biotransformedin some aerobic systems (half-life of 

### 169days),but stable in other aerobic systems and in anaerobic systems. Thus, the degradate is expected to be persistent in most aquatic systems. The 5-OH-XDE-570 degradate is also more persistent than florasulam in aerobic soil (half-lives of 10-56 days), and ismore mobile in soil than the parent compound. Persistence and accumulation of the parent compound are not expected in the field based on laboratory soil studies and terrestrial field dissipation studies. The persistence and accumulation of 5-OH-XDE-570 is more variablethan that of the parent, indicatingthat the compound may persist at some sites, but not others. Submitted data indicatethat the parent compound has a very low potential to bioaccumulate in aquatic organisms.
There is a potential for florasulam to reach surface water through spray drift, as the compound may be applied by ground or aerial sprays. Because both the parent compound and 5- OH-XDE-570 are very mobile in soil, there is also the potential for them to reach surface water through runoff or lateral subsurface flow, although this potential will be somewhat decreased for the parent due to its rapid biodegradation in aerobic soil. For 5-OH-XDE-570, the potential to reach surface water through runoffis greater than for the parent due to its slower biotransformation in aerobic soil and much higher water solubility. For both the parent and the degradate, however, the potential to reach surface water through runoffwill be reduced by any leaching that occurs in the field. Based on the results from the laboratorybatch equilibrium studies and column leaching studies, and supportedby the results of multiple terrestrial field dissipation studies in which leaching was observed, both florasulam and 5-OH-XDE-570have the potential to leach to groundwater. However, for the parent compound, the potential to leach will be somewhat reduced by the fairlyrapid biotransformation of the parent in aerobic soil. For 5-OH-XDE-570,the potential to leach is greater than for the parent due to its slower biotransformation in aerobic soil and much higher water solubility. For either compound, both ofwhich partition mainly to the water phase, the potential to leach will be greaterwhen there is excessiverainfall or irrigation, particularly if either of these occur close to the time of application. These concerns have also been identified inthe Canadian and 

### EU risk assessments for florasulam.

3. Pesticide Type, Class, and Mode of Action 

### a) Chemical Profile
Commonname: florasulam
IUPAC: 

### 2',6',8-trifluoro-5-methoxy[l,2,4]triazolo[l,5-c]pyrimidine-2-sulfonanilide
CAS name: 

### N-(2,6-difluorophenyl)-8-fluoro-5-methoxy[l,2,4] triazolo[l,5-clpyrimidine2-sulfonarnide
CAS NO.: 145701-23-1 Chemical structure:

b) 

### Mode 

### of Action Florasulam is a sulfonamide herbicide intended to control broadleaf weeds postemergence. Sulfonamides are one of several classes of chemicals (with sulfonylureas and imidazolinones) that kill plants through the inhibition of acetolactate synthase (ALS), an enzyme critical to the biosynthesis ofbranch-chain amino acids (valine, leucine, and isoleucine). These chemicals primarily affect plants or meristematictissues that are in an active growth stage. Older plants have been known to exhibitvaried signs ofmalformation, stunting, and reduced fruitheed production when exposed to ALS inhibitors. Weeds can become resistant to individual ALS inhibitors, presumably because these herbicides have a single mode of action and because many have long residual activity. Generally, grasses (Poaceae)tend to be more resistant to ALS inhibitors as they more rapidly metabolize the chemical to nontoxic metabolites than most other plant species. 4. Usage Overview Florasulam is not currently registered for use in the United States;however, the herbicide has been registered for use on cereal grainsin Canada. Thepesticide is proposed for use on wheat, barley, oat, rye and triticale crops for postemergent control ofbroadleaf weeds.

### B. Receptors Ecological effect endpoints are derived from registrant-submitted guideline studies as required for registration under the Federal Insecticide, Fungicide and RodenticideAct (FIFRA; 40 CFR Part 158),as well as a review of data available through acceptable open literature (ECOTOX; www.epa.gov/ecotox),when available. Themost sensitive endpoints (described below) from testing of surrogate species areused to estimate risk to the taxonomic group(s)represented by the surrogate tested. Toxicity testingreported in this document is intended to represent all terrestrial and aquatic organisms. However, only a few surrogate species areused to represent all freshwater fish (2000+), bird (680+) and plant (19,000+) species in the United States. 

### In addition, neither reptiles nor amphibians are routinely tested. Bird data areused as surrogates for reptiles and terrestrial-phase amphibians; fish data are used as surrogates for aquatic-phase amphibians. The Norway rat is typically the surrogate for all mammals. 

### C. Assessment Endpoints Assessment endpoints are defined,per Agency guidelines, as "explicit expressions of the actual environmental value that is to be protected" which are "operationally defined by an ecological entity and its attributes" (USEPA, 2004). The ecological entity can be a species, a functional group of species, a community, an ecosystem, or another entity of importance or concern. An attribute is the characteristic of the entity that is important to protect and ispotentially at risk. Defining an assessment endpoint involvestwo steps: 1) identifllng the valued attributes ofthe environment that are considered to be at risk, and 2) operationally defining the assessment endpoint in terms of an ecological entity (e.g., a community of fish and aquatic invertebrates) and its attributes (i.e., growth, survival and reproduction). Therefore, selection of the assessment endpoints is based on valued entities (i.e., ecological receptors), the ecosystems potentially at risk and the routes by which ecological receptors are exposed to the pesticide. The selection of clearly defined assessment endpoints is important because they provide direction and boundaries in the risk assessment for addressing risk management issues of concern. Typical assessment endpoints for screening-levelpesticide ecological risk assessments include reduced survival and/or reproductive impairment for both aquatic and terrestrial animal species from direct acute or direct chronic exposures. Aquatic animal groupsthat are typically characterized in the risk assessment include: freshwater and estuarine/marinefish and invertebrates. Terrestrial animal groups include birds, mammals, and, qualitatively,beneficial insects. All assessment endpoints are characterized at the individual level in order to protect threatened and endangered species. However, risks to higher biological levels (i.e.,populations and communities) can be inferred from this approach (e.g.,pesticide effects on individual survival and fecundity may impact population stability, growth, and/orhabitat carrying capacity). A species-specific assessment containing characterization of indirect effects to listed species and critical habitat isthe next step following completion ofthe screening-levelrisk assessment. For terrestrial and semi-aquatic plants, the baseline assessment endpoint is the perpetuation of populations ofnon-target species (crops and non-crop plant species). Existing test requirements only evaluate the seedling emergenceand vegetativevigor of annuals. Although it is recognized that the endpoints of seedlingemergence and vegetativevigor may not address all terrestrial and semi-aquaticplant life cycle components, it is assumed that impacts on plant emergence and/or onactive growth have the potential to impact individual competitive ability and reproductive success, from which population effects can be inferred. For aquatic plants, the assessment endpoint is the maintenance and growth of standing crop or biomass. Measurement endpoints for this assessment focus on nonvascular, e.g., algae, and vascular plants, e.g., duckweed (Lemna gibba), growth rates and biomass measurements.
The ecological relevance of the assessment endpoints assumes that complete exposure pathways exist for these receptors, that the receptorsmay be sensitive to pesticides in affected media and/or forage items and that the receptors could potentially inhabit areas where pesticides are applied, or areas where runoff andlor spray drift may impact the sites because suitable habitat is available. Ecological measurement endpoints for this screening-level risk assessment are based on a suite of registrant-submitted toxicity studiesperformed on a limited number of organisms, supplemented by the open literaturewhere applicable,in the followingbroad groupings: 1. Birds, e.g. Northern bobwhite quail (Colinusvirginiana) and mallard duck (Anas platyrhynchos), also used as surrogate species for terrestrial-phase amphibians and reptiles, 2. Mammals, e.g. laboratoryrat (Rattus nowegicus), 

### 3. Freshwater fish, e.g. rainbow trout (Oncorhynchusmykiss), also used as a surrogate for aquatic-phaseamphibians, 4. Freshwater invertebrates,e.g. waterflea (Daphnia magna), 5. Estuarinelmarinefish, 

### e.g.silverside (Menidia beryllina) 

### 6. Estuarinelmarineinvertebrates,e.g.Eastern oyster (Crassostrea virginica) 7. Terrestrial plants, 

### 8. Algae and aquaticplants. Within each ofthesebroad taxonomic groups, an acute and chronic endpoint is selected from the available test data. The selectionis made from the most sensitive species tested within a particular surrogate group. If additional toxicity data are available from other sources, the selection of an endpoint may not be limited to the surrogate species listed above, but maybe expanded to include those data for other groups or speciesthat have been deemed of sufficient quality by the Agency for use in the risk assessment. D. Conceptual Model In order for a chemical to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. Exposurepathways are defined as the means by which a contaminant moves in the environmentfrom a source to an ecological receptor. For an ecological exposure pathway to be complete,it must have a source, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure. Because florasulam's mode of action is the inhibition of branch-chain amino acid synthesis, a metabolic pathway not present in animals, florasulam is not expected to result in direct risk to terrestrial or aquatic fauna. However, florasulam applied in accordance with the proposed label may result in sufficient exposure to nontarget aquatic and terrestrial plants to result in adverse effects 10of 44(e.g.reduction in growth or survival). Additionally, nontarget speciesmay be indirectly affectedby florasulam usage due to a loss of food resources and/or changes to ecologically critical habitat resulting fi-omlabeled uses. 1. Diagram The conceptual model used to depict thepotential ecological risk associated with the use of florasulam (the stressor)assumes that as a pesticide, florasulamcan adversely affect terrestrial and aquatic organisms (thereceptors) if environmental concentrations exceed toxic thresholds as a result of application accordingto the label directions(Figure 1). Ecological receptors that may potentially be exposed to florasulam includeterrestrial and semi-aquatic wildlife (e.g.,mammals, birds, amphibians and reptiles),terrestrial and semi-aquaticplants, terrestrial invertebrates(e.g., honey bees), and terrestrial soil and aquatic sediment invertebrates. Additionally, given the mobility of florasulam and its primary degradate, aquatic organisms (i.e., ffeshwater and estuarine/marinefish and invertebrates,amphibians, and aquaticplants) are potential receptors in adjacent water bodies through off-site transport of florasulam from the application sitethrough runoff, erosion and/or spray drift.
Routes of exposureto terrestrial and aquaticorganisms can occur fi-omdirect application, spray drift and/orrunoff. Exposure maybe through ingestion of contaminated food or water sources,dermal contact or absorption, and/or inhalation. This assessment does not take into account potential atmospheric transport in estimating environmental concentrations or potential exposure via groundwater, nor does it account for ingestion of florasulam residues by animals in contaminated grit, ingestion through preening activities, or uptake through inhalation or dermal absorptionby terrestrial animals. Exposureto terrestrial animals isbased primarily on dietary consumption of foliar (and insect) residues. Aquatic assessments assumethat all potential routes of direct exposure are accounted for.Stressor Florasulam Applied as Aerial or Ground Spray to Target Crops

Sourcel Transport Pathways

Sourcel Exposure Media
Exposure Route

Receptors

Attribute Changes I

Terrestrial Food FoliageiRootslSeeds (foliage, fruits, insects)

Terrestrial Phase Amphibians

Individual Animals Reduced survival Reduced growth Reduced reproduction Reduced survival, dividual Vertebrates and Invertebrates Reduced survival Reduced growth Reduced reproduction



# L

Reduced growth

Bold lines indicate pathways ofprimary concern in this risk assessment Figure 1. Conceptual Model for a ScreeningLevel Assessment of Florasularn. Dashed lines indicate exposure routes not evaluated;bold lines indicate routes of exposure hypothesized to be of greatest importance.

2. 

### Risk Hypothesis Based on the mode ofaction, use ofjlorasulam according to label directions is not expected to result in direct adverse effects to non-target animal species; however, its use as directed may cause adverse effects to nontarget plant species in the environment. Indirect effectson aquatic and terrestrial animal communities may occur due to decreased primaryproductivity. E. 

### Analysis Plan The proposed label maximum application rates for the use of florasulam were selected for modeling environmental concentrations for this baseline, deterministic (risk-quotient based) assessment. The most sensitive toxicity endpointsfrom surrogate test species are used to estimate treatment-related effects on growth and survival assessment endpoints. Estimated environmental concentrations (EECs)used in terrestrial and aquatic ecological risk assessments arebased on florasulam parent compound, as no toxic effectswere reported in studies ofthe degradates. However, the toxicity ofthe primary degradate on terrestrial and aquatic vascular plants remains uncertain.A risk quotient-based approach is used in this assessment, comparing the ratio of exposure concentrationsto effects endpointswith predetermined levels of concern (LOCs). The use, laboratory environmental fate and laboratoryecological effects data, all ofwhich provide the basis for these risk quotients, are characterized in the assessment. Although risk is often defined as the likelihood and magnitude of adverse ecological effects, the risk quotient-based approach does not provide a quantitative estimate of likelihood and/ormagnitude of an adverse effect. 11. 

### ANALYSIS
A. Use 

### Characterization Florasulam is an active ingredient in four formulated productsproposed for the postemergent control ofbroadleaf weeds in wheat,barley, oat, rye and triticale crops. Florasulam is the sole active ingredient in formulatedproduct EF-1343 (4.84%;proposed EPA reg. # 62719-LAN), and is also formulated in combinationwith other active ingredients. EF-1383 (62719-LLI) contains 0.58% florasulam with 42.33% 2,4-D, GF-184 (62719-LAG) contains 0.25% florasulam with 14.53% fluroxypyr and GF-1727 (62719-LAE) contains 0.39% florasulam and 42.25% MCPA. This ecological risk assessment considers the potential for risk from florasulam alone. The other active ingredients have their own risk assessments; the potential for additiveor synergistic effects is not quantitatively consideredin this document. The application rate for florasulam is essentially the same for all four products, but was calculated from the proposed label for EF-1343. All four products are labeled for one application of 0.0045 Ibs ai/A per growing season. Application is limited by the label to one per growing season. While some areas may have more than one growing season per year, it would be an uncommon cultural practice to follow one of the target crops with another ofthe target crops in the same year. Application can be made by ground or aerial spray. Spray drift reduction practices are included on the labels. However, droplet size, 

### an important factor in spray drift, is not limited, although larger droplet size is recommended. Chemigationis specificallyprohibited by the labels. Warnings regarding potential hazard to non-target crop species and crop rotation intervals (0-12months, depending on crop) are included on the labels. An advisory regarding the potential for the products to leach to groundwater is also included on the proposed labels. Application information is presented in Table 2. Table 2. Summary use information for florasulam,based on EF-1343, GF-1727, EF-1383, and GF184 labels.

The formulation of the products was not specifically stated on the proposed labels (each dated 3113/06 with the exception of GF-184, dated 3/07/06), but is assumed to be a liquid 13of44 cereal grains cereal grains 0.0045

0.0045 1

1 0.0045

0.0045 not applicable
not applicable ground spray aerial spray 0 (foliar)

0 (foliar)formulation (possibly a soluble concentrate)for each of the four products. Because florasulam is a new chemical not previously registered in the U.S., the potential extent ofuse cannotbe estimated. However, the widespread distribution ofthe target crops can serve as an index of potential use. According to the USDA National Agricultural Statistics Service (NASS, 2007), wheat is grown in 40 states, 11ofwhich cultivate over one million acres. The most acreage planted in wheat is in Kansas (9,100,000acres) and South Dakota (8,290,000 acres). Barley is grown in 

### 23 states, with the most acreage in North Dakota (1,100,000 acres) and Montana (770,000 acres). Triticale is planted in 27 states, the most acreage in Kansas (291,269 acres) and Oregon (140,062 acres). Rye is planted in two states, Oklahoma (3 10,000acres) and Georgia (230,000 acres). 

### B. Exposure Characterization
1. 

### Environmental Fate and Transport Characterization Florasulam (XDE-570) does not hydrolyze at acid or neutral pHs, but hydrolyzes slowly (half-life of 99 days) at pH 9. The major hydrolysis degradatesat pH 9 are

### N-(2,6-difluorpheny1)-8- fluoro-5-hydroxy(1,2,4)triazolo (13) 

### pyrimidine-2-sulphonamide (5-OH-XDE-570)and a second hydrolysis product for which the structurewas not confirmed. Florasulam photodegrades slowly (adjusted half-life of46 days) in water. The only major degradateis triazolopyrimidine sulphonic acid of florasulam (TSPA). Florasulam is stable to photodegradation on soil. Abiotic degradation (by hydrolysis or photolysis)is not expected to be a significant route of dissipation in the environment.
Florasulam is not persistent in aerobic soil, degrading rapidlyin such, with half-lives of 0.7- 8.3 days in 1 1 soils. Themajor degradates are 5-OH-XDE-570;

### N-(2,6-difluoropheny1)-5- aminosulphonyl- 1 H-

### l,2,4-triazole-3-carboxylic acid (DFP-ASTCA); 5-(aminosulphony1)- 1 H- 1,2,4- triazole-3-carboxylicacid (ASTCA); and 

### 1H-1,2,4-triazole-3-sulphonamide (TSA). Based on the study results and the chemical structures,florasulam appears to biotransfonn rapidly to 5-OH-XDE570, which is then further biotransformedto DFP-ASTCA, DFP-TSA, and polar compounds, eventually forming C02 (range of 5-12%;mean of 9% for 7 soils) and bound residues (range of 15- 57%, mean of 3 1 % for 11 soils). Themajor degradate5-OH-XDE-570 degrades more slowly than the parent in aerobic soil, with half-lives ranging from 10to 56 days in 11 soils, and is labile to moderately persistent. Biotransformation of florasulam is a significant route of dissipation in aerobic soils. Data were not submitted for anaerobic soils.
In aquatic systems, florasulamdegrades with half-lives of 3-1

### 8 days in aerobic systems and 2-13 days in anaerobic systems. In aerobic aquatic systems, florasulam is biotransformedto 5-OHXDE-570, which is then further biotransformed to DFP-ASTCA and STCA (tentative identification). However, 5-OH-XDE-570 degrades much more slowly than the parent, degrading with a half-life of 169days in one aerobic system and remaining stable in another aerobic system. In anaerobic aquatic systems, 5-OH-XDE-570 is stable. Thus, 5-OH-XDE-570 is expected to be persistent in both aerobic and anaerobic aquatic systems. There is a potential for florasulam to reach surfacewater through spray drift, as the compound may be applied by ground or aerial sprays. Because both the parent compound and 5-OH-XDE-570 are very mobile in soil, there is also the potential for them to reach surface water through runoff, although this potential will be somewhat decreased for the parent due to its rapid biodegradation in aerobic soil. For 5-OH-XDE-570, the potential to reach surface water through runoff is enhanced (relative to the parent) by slower biotransformation in aerobic soil. For both the parent and the degradate, however, the potential to reach surface water through runoff will be reduced by any leaching that occurs in the field. Based on the results from the laboratorybatch equilibrium studies and column leaching studies, and supportedby the results of multiple terrestrial field dissipation studies in which leaching was observed, both florasulam and 5-OH-XDE-570 are very mobile in soil and, thus, have the potential to leach to groundwater. 

### In batch equilibrium studies, all measured Kds are less than 1. In an unaged column leaching study,most ofthe applied radioactivityleached through the soil columns (67.7 - 92.1% of applied). The leachatescontained 41.4 

### - 54.3 % of the applied parent compound and 21.5 

### - 39.2% of applied as 5-OH-XDE-570. The parent and the major degradate have been observedto leach in the field as well. In multiple terrestrial field dissipation studies, the parent compound leached to depths as low as 46 cm and 5-OH-XDE-570 leached as low as 61 cm. Greater leaching depths may have occurred, but in several of the studies, the depth of sampling was insufficient. For the parent compound, the potential to leach downward and to reach groundwater will be somewhat reduced by the fairly rapid biotransformation of the parent in aerobic soil. For 5- OH-XDE-570, the potential to leach is enhanced (relative to the parent) by slower biotransformation in aerobic soil and by a much higher solubilityin water. For either compound, both ofwhich partition mainly to the water phase, the potential to leach will be greaterwhen there is excessive rainfall or irrigation, particularly if either of these occur close to the time of application. These concerns have also been identified in the Canadian and EU risk assessments for florasulam. Persistence and resulting accumulation ofthe parent compound is not expected in the field based on laboratory soil studies and terrestrial field dissipation studies. In the seven terrestrial field studies reviewed for this risk assessment 

### (an additional 3 are still in review, but show similar trends), parent DT5Os were 2-19 days (mean of 8.0 days) and DT90s were 16-61days (mean of 32.5 days). At six ofthe sites, the parent was completely dissipated (to below the LOQ 0.01 -0.05 p/kg) from the surface soil by 2 months; at the 7' site it was approximately20% ofthe initial concentration at 2 months and was completely dissipatedby 122 days. The persistence and accumulation of 5-OH-XDE-570 is more variable than that of the parent, indicating that the compound may persist at some sites, but not others. At two sites in Canada, the compound was completely dissipated from the surface soil by 5 months; at the other two Canadian sites, 17% and 28% of the applied (in parent equivalents) remained at the end of the 15-month studies. At two sites in France, the compound dissipated (i.e., fell below limits of quantitation) by 60 and 27 days, with respective half-lives of 17 and 9 days. In a study done in the United Kingdom, the compound was not completely dissipated until 122 days, with a half-life of 95 days. Based on bioconcentration in fish (BCF) values of 0.9-2.OX, florasulamis not expected to bioaccumulate in aquatic organisms. Physical/chemicalproperties of florasulam and the major degradate 5-OH-XDE-570 are presented in Tables 3a and 3b. Table 4 lists other major degradates detected in the environmental

### fate studies. More completeinformation on the submitted environmental fate studies maybe found in Appendix I.

CAS:N-(2,6-difluropheny1)-8- fluoro-5- methoxy[l,2,4]triazolo[1,5- clpyrimidine-2sulfonamide Chemical Name



# my in Water (20 IUPAC: 2N,6N,8-trifluoro-5- methoxy-s-triazolo[1,5- clpyrimidine-2-sulphonanilide

I I I

Hydrolysis Half-life (pH Proposed label

Product Chemistry Molecular Weight

*H 9: 98-100 days (n=2) at 25 "Cand 2 19-226 days (n=2) at 20 OC: 359.3

121mg/L (unbuffered water) @ pH 5 = 0.084 g/L @pH7 = 6.36 g/L @, pH 9 = 94.2 g/L 2.7 x 10'~ Pa pH 5, 7: stable

Aqueous Photolysis Halflife (@ pH 5; in days)

Soil Photolysis Half-life 

# I (days) Product Chemistry

Product Chemistry MRID 46808130

Half-life (days) Very soluble at all environmentally relevant pHs. Relatively non-volatile

Anaerobic Soil Metabolism Half-life

Metabolism Half-life

Metabolism Half-life

Coefficient (Kfor mean MRID 46808 132 Study conducted in natural light; corrected for light intensity,halflife is 46 days (40 ON in
Stable



# I 46827910. Each value is an average half-lifebased on data 0.7, 1.5, 1.7, 1.7,4.5; 3.9, 8.3; 1.0, 1.3; 4.0, 6.0

No data MRID 46808 134.
MRIDs 46808 135 (German and UK soils); 46808138 (Canadianand UK soils); 46808 136 (UK soils); 46808 137 (UK soils)


### -- summer) Study conducted in natural light

3 2, 13

Mean &:0.08, 0.14,0.33,0.35, 0.90,0.94 mL/g (associatedKf values: 0.13, 0.22,0.35,0.89, MRID 4682791 1 MRID 46808 140.

MRID 46827912.

1.4, 1.9d/g)
Mean &:0.02,0.07,0.08,0.09, 0.1,0.13,0.13,0.18,0.33 mL/g from two different labels.

MRID 46808145.

### Table 3b. Physical/chemicalproperties and environmental fate source data for the florasulam major degradate 5-OH-XDE-57( Property -% 2, 

### .., 

### . 3. 

## . YW4 :* 

## ... 

### ., , Log Kow (pH 7)

Henry's Law Constant

PK~

Bioconcentration Factor in Fish (BCF)

Chemical Name 

## I N-(2,6difluorphenyl)-8- @pH4or5- 1.00 @ pH 7 -1.85 @ pH 9 or 10 -2.06 2.93 x 10~'~ atm mbol-'

4.53 (pH 3.0-5.5) 7.22 (pH 6.0-8.5)

0.9-2.OX Product Chemistry

Calculated

Product chemistry

MRID 46808322

Molecular Weight Calculated from vapor pressure, solubility, and molecular weight; Nonvolatile from a water or moist soil surface. Neutral molecule will predominate at pH >4.53 and anionic form will predominate at pH >7.22, so less adsorption expected at higher pHs.

pyrimidine -2-sulphonamide 341.3 Solubility in Water (20 OC)

Vapor Pressure (25 OC) 

### 1 2.7 x 10.~ Pa Hydrolysis Half-life (pH 5, 

## 1 stable

Anaerobic Soil Metabolism Half-lifeAqueous Photolysis Halflife (@ pH 5; in days) Soil Photolysis Half-life (days) Aerobic Soil Metabolism Half-life (days)

No data Not available
Not available 10, 24,26, 29, 3 1; 34, 56;

(days) Aerobic Aquatic 

### 1 169, stable ~etabolism Half-life 

## I (days) I Reviewer-calculated value.

MFUDs 46808135 (German and UK soils); 46808138 (Canadian and UK soils); 46808 136 (UK soils); 46808 137 (UK soils) Product Chemistry.

assumed estimated

MRID 468279 1 1 In MRID 468279 10, data were too variable between labels to calculate a half-life for one s stem, and the 

# I Very soluble at environmentally relevant pHs (and much more soluble than parent cmpd.). Same asparent cmpd. value Conservative estimate based on data from MRID 46808 130. Compound reached its maximum levels (at pH 9) at the end of the 90-day study.Anaerobic Aquatic Metabolism Half-life (days) Soil Adsorption Coefficient (Kd)

Log Kow (pH 7)
Henry's Law Constant

PK~

Bioconcentration Factor in

~ Fish (BCF) stable

Kf:0.07, 0.21,0.24, 0.69, 1.55, 1.73mL/g (mean Kds 0.16, 0.20,0.23, 0.28,0.66, 0.72 mL/g) @ pH 5 = 0.32 @pH7= -1.85 @, pH 9 = -2.32 2.63 x Pa m3mol-'

4.53 (pH 3.0-5.5) 7.22 (pH 6.0-8.5)

No data MRID 46808 140.

MRID 46827912.

Product Chemistry

estimated

Product chemistry.

- compound was stable in the second system.

Calculated from vapor pressure, solub., and mol. wt.;non-volatile from a water or moist soil surface. Neutral molecule will predominate at pH ~4.53; anionic form will predominate at pH >7.22, so less adsorption expected at higher pHs
-Degradate Structures Aerobic Aquatic Metabolism Anaerobic Aquatic Metabolism

Terrestrial Field Dissipation

'~e~radate data are included only for compounds which were degradates in the respective studies. 25-~~-~~~-570 = N-(2.6difluorphenyl)-8- fluoro-5-hydroxy (1,2,4)triazolo (1.5~) pyrimidine 2-sulphonamide; TPSA = (triazolopyrimidine sulphonic acid) of florasulam; DFP-ASTCA = N-(2.6- ditluorophenyl)-5-aminosulphonyl-lH-l.2,4triazole-3-carboxylic acid; ASTCA = 5-(aminosulphonyl)-lH-I,2,4-triazole-3-carboxylic acid; TSA = I H1,2,4-triazole-3-sulphonamide 90-99% (60-1 00 d); 77% (10 d)

83-87% (97 d)

2.98 uglkg (3 d); 0.66 uglkg (14 d); 1.77uglkg (20 d); 18-59%of applied (14-28 d) -

- -

- 14.6% (100 d); 30%(1 yr)

- 16-21% (1 yr)

- -

- MRIDs 46827910, 4680,8143, 46287911

MRID 46808 140

MRIDs 46808 148, 46808 149, 46808 150, 46808206DFP-TSA

DFP-ASTCA

ASTCA

TSA 2. Aquatic 

### Exposure Modeling was conducted to estimate environmental concentrations of florasulam based on the proposed cereal grains use. Estimated Environmental Concentrations (EEC) ofparent florasulam were determined using the Tier 1 screening-level model GENEEC2 (v.2.0; dated 8/1/2002). Input parameter values used in this assessment were selected from the environmental fate data submitted by the registrant and in accordance with US EPA-OPP EFED water model parameter selection guidelines, 

### Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport ofPesticides, Version 11, February 28,2002.
GENEEC2 is a screening-level model designed to estimate the pesticide concentrations found in surface water for use in ecological risk assessments. As such, the model provides upper bound estimates ofthe environmental concentrations (acute and longer-term) in surface water that might occur followingthe use of a pesticide. GENEEC2 uses basic environmental fate data ai-ld pesticide label use and application information to estimate the EECs following the treatment of a 10-hectare field with subsequent runoff into an adjacent 1-hectare, 2-meter-deep "standard" pond with no outlet. GENEEC2 is a single event model (onerunoff event), but can account for spray drift from multiple applications. In the model, the single runoff event occurs two days after the last application and can move a maximum of 10%of the applied pesticide into the pond, with the

### amount dependent on the degradation and adsorption of the pesticide which occurs in the field prior to the event. The model also accounts for degradation which may occur in the pond following the runoff event. Spraydrift (resultingin direct deposition of the pesticide into the pond) in the model is equivalentto 1 % 

### of the applied for ground spray application,and 5% for aerial. Tier I screening-level modelingwas conducted using the maximumproposed application rate of 0.0045 lb ai/A for florasulam, applied onceby aerial spray or ground spray applicationto foliage. Modeling input parametersused with the model GENEEC2 

### are presented in Table 

### 5. The 

### EFED defaults were used for droplet size and boom height, and refinements were modeled based on information in the "Use Precautions and Restrictions" section of the proposed label. Table 5. 

### Input values used for estimating surfacewater concentrations with the Tier I model GENEEC2 

### based on florasulam use on cereal grains.

Application Rate (lb a.i./A) Number of Applications

Interval between Applications (days) Soil Partition Coefficient (b; mL/g)

Aerobic Soil Metabolism Half-life (days)

Wetted in? Depth of Incorporation (inches) Method of Application

Solubilityin Water @ 20 OC, unbuffered (mg/L or ppm) Aerobic Aquatic Metabolism Halflife (days)

Hydrolysis Half-life @ pH 7 (days) 0.0045 1

Not applicable 0.02

4.1

No 0 Aerial or ground spray 121

19.3

stable Proposed label. Proposed label.

Not applicable

MRIDs 46827912 46808 145

MRIDs 46808135 46808138 46808136 46808137 Proposed label. Proposed label. Proposed label.

Product Chemistry. MRIDs 46827910 46827910 MRID 46808130 - Assumed that maximum seasonal application was equal to maximum annual application for the crops listed on the proposed label.

-
Representsthe lowest non-sand 

### I& value among 9 mean 

### &values ranging from 0.02 to 0.33 mL/g or 6 mean 

### I&values ranging from 0.08 to 0.94 (with associated Kfvalues ranging from 0.13 to 1.9). Represents the 90' percentile of the upper confidence bound on the mean of 1 1 half-life values

-

-

-

-



## - Represents the 9oth percentile of the upper confidencebound on the mean of 3 half-life values

-Tier 1 surface water modeling results for both ground spray and aerial spray applications of florasulam to cereal grains are presented in Table 

### 6. Outputs include both estimated environmental concentrations (EECs) derived using the EFED default values and the refinements as noted in table footnotes and based on label restrictions. Complete output files are presented in Appendix 11. Aquatic Photolysis Half-life @ pH 5 (days)

Table 

### 6. Maximum Estimated Environmental Concentrations (EECs) in surface water based on aerial and ground applications of florasulam to cereal grains. Results are reported in parts per 46

Aquatic Exposure Monitoring billion (ppb) and were estimated using the model GENEEC2.

There are no 

### U.S. monitoring data available for florasulam, which is not yet registered for use in the U.S. Monitoring data has reportedly been required as a condition ofregistration by some OECD member countries; however, these data are not yet available. MRID 46808 132

Application Type

Ground spray (w1EFED defaults1) Groundspray (wlrefinements) Aerial spray (wlEFED defaults2) Aerial spray (wlrefinements)

3. Terrestrial Exposure Study was conducted in natural light; value is corrected for light intensity (40°N in summer).

a) Animals Terrestrial wildlife exposure estimates are typically calculated for birds and mammals emphasizing a dietary uptake ofpesticide through residues on vegetative and insect forage items. Avian terrestrial EECs are considered representative ofpotential exposure for terrestrial-phase amphibians and reptiles as well, unless more appropriate data are available through ECOTOX. For exposure to terrestrial organisms, pesticide residues on food items are estimated, based on the assumption that organisms are exposed to a single pesticide residue in a given exposure scenario. Exposure was evaluated using EECs generated from a spreadsheet-based screening model (TREX v. 1.3.1)that calculates the dissipation of a chemical applied to foliar surfaces for single or multiple 

### he EFED default for ground spray is "fine droplets"; the refinement is "medium to coarse droplets." 

### he EFED defaults for aerial spray are "high sprayboom" and ''fine droplets"; the refinements are "low sprayboom" and "coarse droplets." Refinements were selectedbased on proposed label "Use Precautionsand Restrictions." Acute (ppb)

0.1937

0.1751
0.20 17

0.1926 Maximum 4-day Concentration (PP~) 0.1882

0.1700
0.1963

0.1874 Maximum 21- day Concentration (ppb) 0.1602

0.1446
0.1671

0.1595 Maximum 60- day Concentration (ppb) 0.1 145

0.1033
0.1 194

0.1 140 Maximum 90- day Concentration (ppb) 0.0913

0.0823
0.0952

0.0909applications. The terrestrial animal exposure assessment is based on the methods of Hoerger and Kenaga (1972) as modified by Fletcher et 

### al. (1994). When data are absent, as in this case, EFED assumes a 35-day foliar dissipationhalf-life. However, since only one applicationis modeled, the foliar dissipation half-life is not used in calculations for florasulam. Thepredicted maximum residues of florasulam that maybe expectedto occur on selected avian or mammalian food items immediately following application at the maximum rate for a single growing season are presented in Table 

### 7. Since the number of growing seasonsper year is not limited by the label, areas with multiple growing seasons could result in greater exposureson an annual basis. Further details of the model are presented in Appendix 

### IV. Table 7. Unadjusted dietary-based estimated environmental concentrations (EECs) on terrestrial animal forage items following application of florasulam based on TREX (version 1.3.2). I Application Rate Food Items Upper-bound EEC Mean EEC (PP~)~ (PP~)" 0.0045 lbs ai/A Short grass One application Tall grass 

# I Broadleafplants/small insects 0.61 0.20 

# I Fruits, pods, seeds, and large insects 0.07 0.03

a Predicted residues based on Hoerger and Kenaga (1972) as modified by Fletcher et al. (1994). 

### b) Plants Exposure to upland and wetland plants is estimated using the TerrPlant (v1.2.2) screening model. TerrPlant estimatespotential exposure from a single application using default assumptions for runoff and spray drift (Table 8). For runoffplus drift, TerrPlant incorporatestwo similar conceptual models for depicting dry and semi-aquatic areas of terrestrial habitats. For both models, a non-target area is adjacent to the treated field. Pesticide exposures to plants adjacent to the treated field are estimated to include runoff and drift from the treated field. For a dry area adjacent to the treated field, runoff exposure is estimated as sheet runoff. In the model, sheet runoff is defined as the amount of pesticide in water that runs off ofthe soil surface of a treated field which is equal in size to the non-target area (1 :1ratio of areas). For semi-aquaticareas, runoff exposure is estimated as channelized runoff. In the model, channelized runoffis the amount ofpesticide that runs off of a treated field 10times the size ofthe area adjacent to the treated field (10:1ratio of areas). The drift component is calculated as 1 % of applied mass (for ground spray) or 5% of applied mass (for aerial spray). Estimated exposuresthrough runoffplus drift and drift alone are then compared to measures of plant survival and growth (e.g. effects to seedlingemergence and vegetative vigor) to develop RQ values. See Appendix V for more information. Table 8. Estimated environmental concentrations (EECs) on plants following label-specified applications of florasulam determined using the TerrPlantmodel (lbs ai1A) - 

## I Rate 

## I Application Method 

## I Adjacent Upland 

## I Adjacent Wetland 

## I Drift Only

0.0045 lbs ai/A aLoadingis runoff plus drift (lbs aiiA) Aerial Ground Loadings 0.00045 0.00027 Loading 0.00248 0.00230 0.00023 0.00005

### C. Ecological Effects Characterization In screening-levelecological risk assessments, the effects characterization describes the types of effects a pesticide can potentially produce in an animal or plant. This characterization is typicallybased on registrant-submitted studiesthat describe acute and chronic effects information for various aquatic and terrestrial animals and plants; however, registrant-submitted data may also be supplementedby data reported in ECOTOX that have met Agency criteria for acceptability. Toxicity testing reported in this section does not include all species potentially affected by florasulam usage. Only a few surrogate species for fish, aquatic invertebratesand birds are used to represent all species in the United States. For mammals, effects are typically extrapolated from laboratory rat studies. Also, neither reptiles nor amphibians are tested. The risk assessment assumes that avian and reptilian and terrestrial-phaseamphibian sensitivities to the chemical are similar. A similar assumptionis made for fish and aquatic-phase amphibians. Terrestrial plant data are derived from the vegetativevigor and seedlingemergence tests, typically on 10 agricultural crop species, and do not account for potential chronic or reproductive effects. Typically, five aquatic plant species are used to represent potential toxicity to all aquaticplant species.
Most of the studies with non-target organismswere conducted with florasulam technical. The typical end-use product (TEP), EF-1343, was the test material in the terrestrial plant seedling emergence and vegetative vigor studies. These studies provide the effects basis for risk estimation. Further characterizationispossible due the submission ofnon-guideline toxicity studies. The TEP was tested in a daphnid acute study, a rainbow trout acute study, a green algae biomass study, and four qualitative predatory and parasitic arthropod studies. The toxicity of 5-OH-XDE-570was examined in an earthworm acute study, a daphnid acute study, a rainbow trout acute study and a green algae acute study. The transformationproducts DFP-ASTCA, ASTCA, TSA, STA and STCA were also tested in an acute earthworm study. None of the degradates demonstrated greater toxicity than the parent. The studies are summarized in this section; for more detail see

### Appendix 111. 

### PMRA conducted the primary review of these studies; EFED conducted secondary review. 

### ,while generally consistent with PMRA, the OPP study classification is used in this document. A summary of the most sensitive endpoints in this risk assessment arepresented in Table 9. 

### Table 9. The most sensitive endpointsused in the florasulam risk estimation. 

### Type Type of 

### Environment Taxa Endpoint Units MRID 

### of Risk Endpoint Freshwater Aquatic Fish Acute LC50 >lo0 mg ai/L 468083-13 Chronic NOAEC 119 mg ai/L Freshwater Invertebrates Acute ECSO >292 mg ai/L 468083-1 5 Chronic NOAEC 38.9 mg ai/L 468083-2 1 Plants Acute EC5o 1.18 pg ai/L 468083-26 Listed NOAEC 0.62 UE ai/L 468083-26 Terrestrial Avian Acute LD5o 1047 mg aikg-bw 468083-05 Chronic NOAEC 1500 mg aikg-diet 468083-08 Mammalian Acute LDSO 6000 mg aikg-bw 468082-09 Chronic NOAEC 100 mg aikg-bw 468082-35Type Type of Environment Taxa Endpoint Units of Risk Endpoint 

### MRID Plants Acute ECzs 0.00005 lb ai/A 468083-24 Listed NOAEC 0.000009 lb ai/A 468083-24

1. Aquatic Effects 

### a) Fresh water Fish In 96-hour acute static toxicity studies, rainbow trout (Oncorhynchusmykiss) and bluegill sunfish (Lepomis macrochirus) were exposed to florasulam at a concentrationof 100 mg ai/L. No mortality or other adverse effects were observed. The 96-h LCSo and NOAEC values, based on mortality and non-lethal adverse effects, were >I00 and 100 mg ai/L,respectively. Florasulam is classified as practically non-toxic to freshwater fish on an acute exposure basis. The chronic toxicity of florasulam to rainbow trout was assessed in a 28-day fish early life stage toxicity study, conductedunder flow-through conditions. The fish were exposed to meanmeasured concentrationsof 9.6, 14.8,25.9,43.8,70.9and 119 mg ai/L. Although there were three mortalities in the negative control, there were no mortalities or sublethal effects observed at any test concentration. The 28-day NOAEC was 119 mg ai/L.


### TEP and Transformation Products A 96-h acute toxicity studywas conducted in which rainbow trout were exposed to the TEP, EF-1343, at a concentration of 100 mg EF-1343/L under semi-static conditions. No mortality or other adverse reactions were observed. The 96-h and NOAEC values, based on mortality and non-lethal adverse effects, were >lo0 and 100 mg EF- 1343/L,respectively. The formulated product, EF-1343, is classified as practically non-toxicto rainbow trout.
In a 96-hour acute static toxicity study, rainbow trout were exposed to 5-hydroxy-XDE-570 at a concentration of 100 mg ai/L. No mortality or other adverse reactions were observed. The 96- hour LCsoand NOAEC values were >lo0 and 100mg/L, respectively. The transformation product 5-Hydroxy-XDE-570 is practically non-toxic to rainbow trout.


### b) Freshwater Invertebrates An acute 48-hour static toxicity studywas conducted to determine the effects of florasulam on water fleas (Daphnia magna). The mean-measured test concentrations were 0 (control), 38, 63, 104, 174 and 292 mg ai/L. At 48 hours, there was 20% immobilization observed at the highest concentration. No effects were observed at test concentrations of 174 mg ai/L and lower. Therefore, the 48-h ECS0 value was >292 and the 48-h NOAEC was 174 mg ai/L. Florasulam is classified as practically non-toxic to daphnidson an acute exposure basis.
A chronic 21-day (life-cycle) semi-static toxicity studywas conducted to determine the effects of florasulam on daphnids. The nominal test concentrations were 0 (control), 14,23.3,38.9, 64.8, 108, and 180 mg ai/L (mean-measured 13.7-1 76 mg ai/L),to which first instars were exposed.Ten replicates of one daphnid each were used to evaluate effects on reproduction and growth, and three replicates of five daphnids each were used to evaluate effects on mortality. The 21-day NOAEC for the length and weight of adult daphnidswas 38.9 mg ai/L.


### TEP and Transformation Products
An acute 48-hour static toxicity studywas conducted to determine the effects ofthe TEP, EF-1343 on daphnids. The daphnids were exposed to a singlenominal concentrationof 100mg EF1343lL [(mean measured concentrationwas 5.5 mg ai/L (1 10%of nominal)]. No immobilization or other sub-lethal reactions were observed in the treatment for 48 hours. The 48-h ECSo and NOAEC were >100 and 100 mg EF- 1343/L,respectively. EF- 1343is classified as practically non-toxic to daphnids.
An acute 48-hour static toxicity studywas conducted to determine the effects of 5-hydroxyXDE-570 on daphnids. A singlemeasured concentrationof 96.7 mg ai/L was tested. No mortality or sublethal effects were observed over 48 hours. The 48-hour ECsoand NOAEC values were >96.7 and 96.7 mg aiIL, respectively. Therefore, 5-Hydroxy-XDE-570is classified as practically nontoxic to daphnids. In another study, the acute toxicity of five transformation products of florasulam to daphnids was assessed over a 48-hour test period. Daphnids were exposed to two nominal concentrations of 3 and 30 pg ai/L each of DFP-ASTCA, ASTCA, TSA, STA, and STCA. There was no mortality or immobility observed following 48 hours of exposureto either of the two concentrations of any of the transformationproducts tested. The 48-hour ECSOs and NOAECs were >30 and 30 pg ai/L, respectively, for each of these transformation products.


### c) Estuarinemarine Fish In an acute static toxicity study, silverside (Menidia beryllina) were exposed to florasularn at a mean measured concentration of 122mg ai/L, prepared with filtered natural sea water. No mortality or other adverse reactions were observed. The 96-hour LCsoand NOAEC values were >I22 and 122 mg ai/L,respectively. Florasulam is classified as practically non-toxic to estuarinelmarine fish on an acute exposure basis. d) 

### EstuarinemarineInvertebrates A 96-hour acute toxicity studywas conducted under static conditionsto determine the effect of florasulam on the grass shrimp (Palaemonetes pugio). The shmpwere exposed to a mean measured concentration of 120mg ailLprepared using natural sea water. There was no mortality or other adverse effects. The 96-hour LCsO and NOAEC were >I20 and 120 mg aiIL, respectively. Florasulam is classified as practically non-toxicto estuarinelmarineinvertebrates on an acute exposure basis. 

### e) Aquatic Plants In a 72-hour static laboratory toxicity test, the freshwater unicellular green alga, Selenastrum capricornutum, was exposed to the end-useproduct EF-1343 at mean measured concentrations of 0 (control), 0.458, 0.92, 1.75,3.59, 6.9 and 11.9pg ai1L. Exposure to EF-1343 at concentrations greater than or equal to 3.59 pg ai1Lresulted in a significant reduction in both the average growth rate and the biomass compared to those ofthe control. TheNOEC and ECSo values, based on biomass, were 1.75 and 3.45 pg aiIL, respectively. 26 of 44In a 14-day static toxicity test, duckweed (Lemnagibba) was exposed to florasulam technical at measured concentrations of 0 (control), 0.137, 0.306,0.6 16, 1.35,2.3 and 4.59 pg ai/L. After 14 days, inhibition of growthranged from -5.4% at 0.137 pg ai/L to 93.3% at 4.59 pg ai/L when compared to the solvent control. The NOEC and ECsovalues,based on frond number, were 0.62 and 1 .18 pg aiIL, respectively.
Transformation Products Cultures of the freshwater unicellular green alga, S. capricornutum, were exposed to 5-hydroxyXDE-570 at measured concentrations of 0 (control), 3.48,6.64, 13,25.4,49.5 and 96.1 mg/L under static conditions for up to 96 hours. Significant inhibition of growth was evident in cell count data at 13mg/L and above. There were no other compound-related phytotoxic effects. The NOEC, EC2S and EC5() values, based on cell count, were 6.64, 11.59 and 25.57 mg 5-hydroxy-XDE-570/L, respectively.

2. 

### Terrestrial Effects a) Avian Acute Oral, Dietary and Chronic The acute oral toxicity of florasulam to 8-week-old Japanese quail (Coturnix japonica) was assessed over 14days. Florasulam was administered to the birds by gavage in corn oil as a single oral dose at nominal concentrations of 0 (control), 175,292,486, 810, 1350 and 2250 mg aikg-bw. Toxic sublethal effects (lower limb weakness, wing droop,reduced reaction to sound and movement) were observed at 292 mg a.i./kg-bw and above, and were more severe at 2250 mg a.i./kg-bw. Mortality was 40,60, and 100 % in the 810, 1350, and 2250 mg ailkg treatments, respectively. The NOAEL (based on sublethal effects) and LDS0were 175 and 1047mg aikg-bw, respectively. Florasulam is classified as slightly toxic to Japanese quail on an acute oral exposure basis. The subacute dietary toxicity of florasulam to 11 -day-old Japanese quail and mallard duck (Anusplatyrhynchos) was assessed over 8 days. Florasulam was administered to the birds in the diet at nominal levels of 0 (control), 312, 625, 1250,2500and 5000 mg aikgdiet. There were no compound-related toxic effects. TheNOAEC and LCso were 5000 and >5000 mg aikgdiet, respectively. Florasulam is classified as practically non-toxic to Japanese quail and mallard duck on a subacute dietary exposurebasis. The chronic toxicity of florasulamto 20-week-old bobwhite quail (Colinus virginianus) and 28-week-old mallard duck were assessed over 21 and 23 weeks, respectively. The adult bobwhite quail and mallard duck were fed diets containingflorasulam at nominal concentrations of 0 (control), 240, 600 and 1500mg aikgdiet prepared with the aid of acetone and corn oil. There were no compound-related toxic effects at any of the concentrations tested. The NOAEC for chronic toxicity to birds is 1500 mg aikgdiet.

### b) 

### Mammalian Acute and Chronic Florasulam is classified as practically non-toxic to rats (Rattus nowegicus; MRID 46808209) with acute oralNOAEL and LDSO values of 6000 mg aikg-bw and >6000 mg aikg-bw, respectively. No adverse effects were observed at any of the doses tested. A 2-generation reproduction (MRID 46808235) study on rats reported a parental NOAEL of 100mg aiikgbwld and a NOAEL of 500 mg ailkgbwld for offspring and reproductive effects. The effects on the parental generation were reduced growth (weight loss) at the highest concentration tested. However, effects on these parameters were accompanied by an observed reduction in food consumption. Whether the reduced feed consumption was a result of a palatability issue or a chemical-induced anorexia is uncertain, although other chronic and subchronic studies (dog, rabbit) reviewed by the Health Effects division report similar observations.



### c) Nun-target Invertebrates Honeybees
In a 48-hour acute oral toxicity study, honey bees (Apis mellifera) were exposed to florasulam via diet at the rate of 100pg aihee. After 48 hours, 10% mortality was observed in the two replicate groups which had consumed the equivalent rate of 100pg aihee. 

### In the third replicate group, bees consumed only 80 pg aihee. Mortality in this group was 20%. The mortalities were not dose-related, but a NOAEC could not be estimated from these data. The was >I00 pg aihee;therefore, florasulamis classified as practically non-toxic to honeybees on an acute oral exposure basis.
In a 48-hour acute contact toxicity study,honeybees were exposed to florasulam, administered topically at the nominal rates of 0 (control), 

### 6.3, 12.5,25,50 and 100pg aihee. There was 5% mortality in both the negative and positive controls as well as the 100pg aihee treatment level. The mortalities were not considered to be dose-related. The 48-hourNOAEC and LCs0 were, therefore, 100 and >I00 pg aihee, respectively. Florasulam is classified as practically non-toxic to honey bees on an acute contact exposure basis. Degradate and formulation toxicity
For the major transformationproducts, two 14-dayacute earthworm toxicity studies were conducted. In one study, earthworms were exposed to 5-hydroxy-XDE-570 at the measured rates of 0 (control), 141,225, 399,678, and 1120 mg ailkg artificial soil. In another study, earthworms were exposed to each ofthe transformation products, DFP-ASTCA, ASTCA, TSA, STA, and STCA, at concentrations of 0 (control), 10 and 100 yg ailkg artificial soil. For the test with 5-hydroxy-XDE570, no significant mortalities or sub-lethal effects were observed in treatment and control groups during the 14-day exposure period. The NOEC and LC50 were 1120 and >I120 mg aiikg soil, respectively. Survival of worms exposed to each of the other five transformation products averaged 93 to 100% after 14days. Thel4-day LCSOs were >I00 pg aikg. For sublethal effects, significant lethargy was noted at the 100pg aikgtreatment levels of DFP-ASTCA, ASTCA, and TSA at the end ofthe test. Therefore, the 

### NOAEC values were 10pg aikgfor these three transformation products and 100yg aikgfor STA and STCA. 28 of44In addition to the above studieswith the technical active, five studies were conducted with the TEP (EF-1343) to test the effect ofthe herbicideproduct on earthworms (one study) and honey bees (four studies). Results of these studies were consistent with the studies conducted with the technical florasulam, as no dose-related deleterious effects were noted in these studies.
Four studies were also conducted to test the effect of the end-use formulation on the predatory green lacewing (one study), a predatory phytoseiid mite (one study), a parasitic wasp (one study) and a predatory carabid beetle (one study). These supplementary qualitative data did not demonstrate toxicity to these beneficial predators or parasites.


### d) Terrestrial Plants In a seedling emergenceand 2 1 -day vegetativevigor laboratory toxicity test, a total of four monocotyledonous species [corn (Zea mays), oat (Avena sativa), onion (Allium cepa) and ryegrass (Lolium spp.)] and six dicotyledonous species [carrot (Daucus carota), cucumber (Cucumis sativus), radish (Raphanus sativus), soybean (Glycine max), sunflower (Helianthus annuus) and tomato (Lycopersicon esculentum)] were exposed to a single application of the TEP, EF-1343. The rates of EF-1343 (4.84% a.i.) applied to all speciesin both tests ranged from 0.00001 lbs ailA to 0.0089 lbs ailA (which bracket the proposed application rate of 0.0045 lbs a.i./A) in a natural soil. EF-1343 demonstrated no statistically significant inhibition on the emergence, length or biomass of any species tested, except radish emergence. While the EC25 for radish is >0.0089 lbs aiIA, the NOEC is 0.001 1 lbs ai1A; for the remaining species tested, the NOAEC and EC25 are at treatment concentrations equivalentto application rates of 0.0089 and >0.0089 lbs a.i/A,respectively,
In the vegetativevigor test, the most sensitive endpoints,based on an EC25of 0.00005 lbs ai/A, were sunflower and tomato shoot length and carrot shoot weight (biomass). The NOEC, based on sunflower and tomato shoot length, was 0.000009 lbs ai1A. The other dicot specieshad EC25 values ranging from 0.00006 lbs ai1A (tomato biomass) to 0.0015 lbs ai/A (soybean shoot length). Onion, a monocot, had an EC25for biomass of 0.0006 lbs ailA and a NOEC of 0.0001 lbs ailA. The three grass species were unaffected in terms of biomass or shoot length,but all were reported to show visual signs of phytotoxicity (chlorosis, stunting) at 0.0089 lbs ailA, the highest treatment rate. While the grass species (Family: Poaceace) were tolerant of florasulam treatment, the other monocot tested, onion (Family: Liliaceae) was sensitive to florasulam. 

### 3. 

### ECOTOX The Agency's publicly-availableECOTOX database (www) was reviewed for toxicological endpoints. There were no data on florasulamin the database when accessed 0311312007.
Four open literature papers characterizing the efficacyand selectivityof florasulam were identified by ORD as passing the OPP and EFED ECOTOX relevance screen. In one oftwo papers on efficacy, Paterson et al. (2001) conducted field tests [conducted in four countries] of florasulam's effect on Galium aparine, a common weed species. The study found that while most G. aparine was controlled with at least 80% effectiveness(EC8O)at application rates between 0.0027 and 0.0009 lbs ai/A (based on wet weight), four of the 20 test populationsrequired an application rate ashigh as 0.0045 lbs ai/A to achieve control. In the second paper, Paterson et al. (2002) conducted 

### a greenhouse study with field poppies (Papaver rhoeas) and reported an ECsorange from 0.0016 to 0.0077 lbs ai/A, based on visual assessments. Three of the 15populations studied required application rates greaterthan 0.0045 lbs ai/A.
In the selectivity studies, Rijckaert and Lepiece (2003) applied florasulam to Festuca rubra and ryegrass (Loliumperenne) cultivarsintended for grass seed production at 1 

### X and 

### 2X the proposed label rate (0.0045 lbs ai/A) and found no significant difference in seed production or straw yield. Additionally,Rijckaert and Lepiece (2001) treated bentgrass (Agrostis stolonifera), fescue 

### (F. rubra), prairie Junegrass (Koeleria macrantha) and Italian ryegrass (Lolium multzflorum) with 

### 1X and 2X the proposed label rate and concluded that there was no significant difference in seed production or straw yield. These are desirablegrass species and these studies are intended to emphasize that at the proposed applicationrate, florasulam will not adversely affect these species. 111. RISK CHARACTERIZATION The risk quotient (RQ) approach is used in this assessment, comparing the ratio of exposure concentrationsto effects endpoints with predetermined levels of concern (LOCs). Laboratory environmental fate, laboratoryecological effects, and use data that provide the basis for these risk quotients have been discussed previously in the assessment. Although risk is often defined as the likelihood and magnitude of adverse ecological effect, the risk quotient-based approach does not provide a quantitative estimate of likelihood andlormagnitudeof an adverse effect. Estimated environmental concentrations (EECs) are divided by acute and chronic toxicity values to calculate RQs. If the RQs exceed the LOCs, the Agency presumes potential for risk to the taxa. These LOCs (Table 10)are the Agency's interpretive policy and are used to determine the need to consider regulatory action by indicating whether a pesticide,used as directed on the label, has the potential to cause adverse effects on non-target organisms. Table 10. Levels of concern (LOCs) for various taxa. 

### Risk Presumption 

### RQ LOC BirdsAcute Risk EEC/LC50 or LDso/sqft or LDsdday 0.5 Acute Restricted Use EEC/LCSo or LDSO/sqft or LDsdday (or LDsO < 50 mglkg) 0.2 Acute Endangered Species EEC/LCSo or LD5a/sqftor LDsdday 0.1 Chronic Risk EECNOAEC 1 Wild Mammals Acute Risk EEC/LCSo or LD5dsqfior LD,dday 0.5 Acute Restricted Use EEC/LCSo or LDSdsqftor LD5dday(or LDS0 < 50 mgtkg) 0.2 Acute Endangered Species EEC/LCSo or LD50/sqft or LD~dday 0.1 Chronic Risk EECNOAEC 1 

# IAquatic Animals 30 of 44Risk Presumption 

### RQ LOC Acute Risk EEC/LCSo or ECsO 0.5 Acute Restricted Use EEC/LCSo or ECSo 0.1 Acute Endangered Species EEC/LCSo or ECS0 0.05 Chronic Risk EEC/NOAEC 1 Terrestrial and Semi-Aquatic Plants Acute Risk EECIEC25 1 Acute Endangered Species EECNOAEC or ECoS 1 Aquatic Plants Acute Risk EEC/ECSo 1 Acute Endangered Species EEC/NOAEC or ECos 1 A. Risk Estimation Based on the most sensitive endpoint for each ofthe taxa evaluated, only the RQ values for non-target terrestrial plants exceed the LOC for the proposed uses of florasularn. 1. Aquatic Species 

### a) FreshwaterFish Florasulam is classified as practically nontoxic on an acute exposure basis to freshwater fish, 

### i.e. the LCsois greater than 100mg/L, and the potential for acute risk to freshwater fish is presumed to be low. An RQ calculated using 100mglL (thehighest dose tested) is several orders of magnitude below (calculated RQ <2x10-~) even the acute risk to listed species LOC of 0.05. The RQ for chronic effects to freshwater fish is also orders ofmagnitude below (calculated RQ~lxlo-~) the chronic risk LOC of 1.O. b) FreshwaterInvertebrates Florasulam is classified aspractically nontoxic on an acute exposure basis to freshwater invertebrates (LCso>292 mg/L), and the potential for acute risk to freshwater invertebrates is presumed to be low. RQs calculated from the most sensitive endpoint in the submitted studies are several orders ofmagnitude below (calculated ~~<6.9x1 o-~) even the acute risk to listed species LOC of 0.05. The RQ for chronic effects to freshwater invertebrates is also orders ofmagnitude below (calculated RQ<~X~ o-) the chronic risk LOC of 1

### .O. c) Estuarine/MarineFish Florasulam is classified as practically nontoxic on an acute exposure basis to estuarinelmarine fish, i.e. the LCsois greater than 100mg/L, and the potential for acuterisk to estuarinelmarine fish ispresumed to be low. The RQ calculated using 100mg/L (the highest dose tested) is several orders ofmagnitude below (calculated RQ<~x~o-~) even the acuterisk to listed species LOC of 0.05. There are no chronic toxicity data available with which to calculate a chronicRQ for estuarinelmarine fish. 

### d) Estuarinemarine Invertebrates Florasulam is classified as practically nontoxic on an acute exposure basis to estuarinelmarine invertebrates, i.e. the LC50 is greaterthan 100mg/L, and the potential for acute risk to estuarinelrnarine invertebrates is presumed to be low. The RQ calculated using 100mg/L (the highest dose tested) is several orders of magnitudebelow (calculated RQ<~x~o-~) even the acute risk to listed species LOC of 0.05. There are no chronic toxicity data available with which to calculate a chronic RQ for estuarinelmarine invertebrates. 

### e) Aquatic Plants No RQ for aquatic plants exceeds the LOC. Using the highest modeled aquatic EEC (0.202 ppb) for florasulam, the RQ for listed nonvascular aquatic plants is 0.17 and is well below the acute risk to listed species LOC of 1.O. The RQ for listed vascular aquatic plants is 0.33 and is again below the acute risk LOC of 1.O. Since protections for listed species are greater than for non-listed species, the presumption of low risk to listed species extends to non-listed species as well. 

### 2. Terrestrial a) Avian Acute and Chronic When both dose-based and dietary-based toxicity estimates are available for birds, acute risk quotients are calculated using both a dose-based and dietary-based approach. The dose-based RQs are calculated using a body weight-adjusted and consumption-weighted equivalent dose. The adjustments account for the fact that smaller-sized animals have to consume more food in terms of their body weight than larger animals and that differential amounts of food have to be consumed depending on the water content and nutritive value ofthe food. By expressing the Kenaga nomogram (Fletcheret al. 1994)estimated residues in terms ofdaily equivalent dose, estimated environmental concentrationscan then be compared to the dose-based LD50. However, florasulam is classified as practically nontoxic to birds on a subacute dietary exposure basis; therefore, the potential for risk is presumed low. Themost vulnerable birds (small birds foraging on short grass) with the greatest exposure have RQ values of <0.0002 based on the highest dietary concentration tested. While florasulam is classified as slightly toxic to birds on an acute oral exposure basis, the highest dose-based RQ is 0.001 6 and is two orders of magnitude lower than the acute risk to listed species LOC of 0.1. No effects on any adult, offspring or reproductive parameter were observed at the highest dose tested in the two submitted avian reproduction studies (NOAEC=l500 mgkg-diet). All chronic RQ values are ~0.01 and as such are more than two orders of magnitude below the chronic risk LOC of 1.O. 

### b) MammalianAcute and Chronic No adverse effects were seen at the highest dose tested (6000 mg ailkg-bw) in the rat acute oral toxicity study, and florasulam is classified as practically nontoxic to mammals on an acute oral exposure basis; therefore, risk is presumed to be low. Using the highest dose tested, the highest RQ (small mammals foraging on short grass) would be <0.00009 and is well below the acute risk to listed species LOC of 0.1.Although parental effects were observed at the highest dose tested (500 mg ailkg-bw) in the rat reproduction study,no effects on reproductive or growth~survival of offspring were observed. Using the parental NOAEL (100 mg aikg-bw), all chronic mammalian RQs are <0.01 and are below the chronic risk LOC of 1.O. c) Nontarget Plants RQs for upland plants 

### (Table ll),as well as for monocots and unlisted dicots adjacent to the application site, are below the non-listedplant speciesLOC of 1.O. RQs for listed dicots inhabiting wetlands exceed the listed speciesLOC of 1.0by more than a factor of two for both aerial and ground applications. RQ values for non-listedmonocots from drift alone do not exceed the LOC. The RQ for listed monocots is 2.25 when florasulam is applied aerially, but does not exceed the listed species LOC for ground application. The RQ for non-listed dicot species exposed to florasularn drift is 4.5 for aerial application,but the LOC for non-listed dicots is not exceeded for ground application. RQ values for listed dicot species from drift alone, 25 for aerial and 5.1 for ground, exceed the LOC for listed plant species.


### Table 11.Risk auotients for terrestrial ~lants from Termlant v1.2.2. 

# I Application

# I Adjacent Upland 

# I Adjacent Wetland Method Drift Only

Nonlisted

"bold indicates RQ exceeds LOC Listed Nonlisted Listed

Because the use of florasularn indicatesrisk to plants using the default drift assumptions in TerrPlant, A~DRIFT@ was used to refine the drift assumptions and risk estimates. Using the EECs derived from the 

### A~DRIFT@ model (v.2.01; default inputs), the RQ (1.1;Table 12) exceeds the LOC (1-0)for non-listed species at 900 ft from the site of aerial application. The RQ for listed plants exceeds the LOC more than 6-fold. For ground applications, the RQ for non-listed plants (0.8; Table 13) is below the LOC at 100

### fi from the application site, but the RQ for listed plants exceeds the LOC out to 500 

### ft from the treated field. Aerial



### Table 12. Terrestrial Plant RQs at Listed Distance from Site of Aerial Florasulam Application

aboldindicates RQ exceeds LOC Ground Monocot <0.05 0.05 c0.03 0.03 Dicot 0.05 0.41 c0.03 0.25 Monocot <0.28 0.28 <0.26 0.26 Dicot c0.28 2.25" c0.26 2.09 Monocot 0.38 Dicot 4.50 2.25 0.08 0.45 25.3 0.90 5.06Table 

### 13. Terrestrial Plant RQs at Listed Distance from Site of Ground Florasulam Application based on 

### A~DRIFT@ Modeling. 

# I Unlisted 

# I Listed 

# I

- - 

# rDistance EEC RQ RQ

"bold indicatesRQ exceedsLOC B. Risk Description Florasulam is being proposed for the post-emergent control ofbroadleaf weeds in wheat, barley, rye and triticale crops. The compound is not persistent in aerobic soils and degrades to 5- OH-XDE-570. Both florasulam and its primary degradate are very mobile. Florasulam can move to surface water through spraydrift. Although florasulamis not persistent in aerobic soils, the compound and its degradate can move to surfacewater through runoff or subsurface lateral flow following high rainfall events soon after application,and may leach into groundwater. The potential for leaching to groundwater is greater for the degradate, due to its greater persistence in aerobic soils and its much higher water solubility. Florasulam is practically nontoxic to aquatic and terrestrial animals on an acute exposure basis. Toxicity studies with florasulam degradates suggest that they are no more toxic than the parent. Consistent with the intended use of the compound as an herbicide, both aquatic and terrestrial plants exhibit a range of sensitivities to florasulam.
In spite ofthe mobility of florasulam,estimated exposure concentrations combined with low toxicity to both terrestrial and aquatic animalsresult in RQ valuesbelow acute and chronic risk LOCs. However, the increased sensitivity of plants to florasulam results in RQ values which exceed LOCs for plants. Based on this baseline deterministicrisk assessment,EFED cannot refute the risk hypothesis that the proposed label uses of florasulam may pose risk of adverse effects to non-target terrestrial plant species. Consistentwith the risk hypothesis, potential direct risk to aquatic and terrestrial animals appears to be low. Contrary to the risk hypothesis, the potential for adverse effects to aquatic plants also appears to be low. However, indirectrisk from potential changes in food availability or habitat through effects on plant populations or communities cannot be precluded and remains an uncertainty. 1. Aquatic As presumed in the risk hypothesis, the potential for direct effects to aquatic animals from the use of florasulam appears to be low. RQs are at least four orders of magnitudebelow the listed species 

### LOC for both acute and chronic effectsto fish and invertebrates. However, because of the potential for florasulam to alter terrestrial plant communities, aquatic animals could be adversely affected through changes in habitat. These changes could include loss of spawning habitat, shelter or food sources, or increases in water temperaturethrough reduction in stream-side shade plants. RQs for listed aquatic vascular and nonvascular plant species are well below the LOC of 1.O.The application rate would need to be approximately 10Xthe proposed label rate of 0.0045 lbs ai/A for the listed nonvascular plant LOC to be exceeded, and roughly 3X the proposed label rate in order for the listed vascular plant LOC to be exceeded. Conversely, the NOAEC for aquatic vascular plants would need to be 113 the NOAEC from the Lemna gibba study for the LOC to be exceeded. While florasularn is not considered highly toxic to aquatic vascular plants based on the study submitted for this assessment, the guidelinerequirement is limited to a single study evaluating the response ofLemna gibba, a small monocot. Although not all monocots share the ability of wheat and some other grasses to rapidly degradeALS inhibitors to less toxic forms, the degree to which the sensitivity ofLemna spp. isrepresentative of other aquatic vascular plants is uncertain. Fairchild et al. (1998), in a comparative study of several herbicides, reports that Lemna minor is of intermediates sensitivity, as much as five-fold less sensitivethan other aquatic vascular plant species in the study. However, relative species sensitivitywas dependent on the chemical used, and ALS inhibitors were not evaluated. If other species of aquatic vascular plants are more sensitive to florasulam than Lemna gibba, the potential for risk would be higher then indicatedby the RQs derived for this assessment. 2. Terrestrial Based on the analysispresented in this risk assessment,the potential for direct risk to listed and non-listed terrestrial animal species appears to be low. Calculated acute and chronic RQs, based on the upper-bound EECs, are several orders ofmagnitudebelow LOCs. The highest RQ for terrestrial animal species is 0.0016 for small (20-g) birds foraging on short grass. While effects, including mortality, were observed in the avian acute oral toxicity study and sublethal effects on adult weight were observed in the chronicrat study, the EECs for florasulam are well below those effect thresholds. Toxic effects, including some mortality (20% or less), were observed in the bee studies, the effects occurred at the highest dose tested (100 pghee), and the LDS0 was >I00 pghee in both studies. However, EFED considers an LDjO 

# > 11pg/bee to indicate a chemical is practically nontoxic to bees; therefore risk to bees appearsto be low. As expected with an herbicide, there is a potential for risk to listed and unlisted terrestrial plant species from the use of florasulam. While the onlyrunoff-based RQs that exceed the LOC are for listed dicots in wetland habitats, variabilityin the seedlingemergence study (as discussed below) introduces uncertainty as to whether the most sensitive endpoint was defined. Due to the nature of exposure in the vegetativevigor study (foliar spray), endpointsderived from that study are inappropriate for estimating risk from runoff exposure; only the seedling emergence results are used to evaluate potential risk from runoff. Since florasulam is a systemic herbicide, uptake through the roots is a potential source of exposure to plants, but current guideline studies do not address potential effects from this route of exposure. However, if effects were seen on vegetative vigor at the same exposure threshold via root uptake as via foliar spray, RQs would exceed the LOC for every category except upland monocots. While there was statisticallyno effect greater than 25% on the emergence, shoot length or biomass of any of the species tested in the seedlingemergence study, several species (carrot, onion, soybean, cucumber, tomato) exhibited inhibitionsranging from 5% to 26% in these parameters at rates as low as 0.00001 lbs ai/A. The seedlingemergence studywas highly variable which likely 

### 35 of 44contributedto a lack of statisticalpower. Despite the fact that florasulam is not labeled as a preemergent herbicide, ALS inhibitors are typically most effective in actively growing plants, such as seedlings. Therefore, there may be potential for deleterious effects on sensitive non-target plant populations through decreased seedlingemergence and possibly decreased vigor in the young seedlings. Because ofthe high degree of variability in the study, it cannot be definitively determined to what degree these effectsmay occur in the field. For instance, at 0.00001 lbs ai/A (the lowest dose tested), tomatoes exhibited a mean 26% reduction in biomass relative to the control, but at 0.0029 lbs ai/A, a mean 5% increase in biomass relative to the control was observed. The replicate coefficients of variance (CV) for the treatmentsranged from 12.4% to 80.5%, while the control CV was 3.4%. This suggeststhat the control data are closely clustered and that the variability observed in the treatment groups is related to the chemical treatment. The variability in this study is a source of uncertainty in this assessment. Using the default assumption of fine-medium(ASTM S572) droplet size in AgDRIFT modeling, the LOC for terrestrial plants is exceeded even at 900 

### ft from the site when florasulam is applied aerially. The proposed label recommends that drift can be controlledby the use of larger droplet sizes, although it is not directive, statingthat applications should be made "with a minimum of fine spray droplets." When medium-coarseand coarse-very coarse droplet-size spectra are modeled, the RQs are reduced (Table 14). For non-listed plants, increasing the droplet size to medium-coarse reduces the RQ below the LOC by 500 

### ft from the application site. When the coarse-very coarse droplet size is modeled, the LOC is not exceeded at 300 

### ft fiom the treated field. The LOC for listed species is exceeded at 900 

### ft (the limit of the model) from the treated field following aerial application regardless of the droplet size modeled,but is reduced by approximately half with each increase in droplet size (Table 15). 

### Table 14. RQs for non-listed plants at listed distance from aerial application site of florasulam using various droplet-size spectrabased on AgDRIFT EECs and the vegetative vigor endpoints. Droplet Size Spectrum (ASAE S572) Coarse-Very 

# I Fine-Medium 

# I Medium-Coarse 

# I
coarse

"boldindicates exceeds LOC

Distance 100' 300'



### Table 15. RQs for listed plants at listed distance from aerial application site of florasularn using various droplet-size spectrabased on AgDRIFT EECs and the vegetative vigor endpoints. Droplet Size Spectrum (ASAE S572) Coarse-Very 

# I Fine-Medium 

# I Medium-Coarse 

# I Coarse EEC 0.0004 0.0001 RQ 8.0a 2.0

Distance 100' EEC 0.0003 0.000068

EEC 0.0004 RQ 6.0 1.4

RQ 44.4a EEC 0.0002 0.000041

EEC 

## I RQ 0.0003 

## 1 33.3 RQ 4.0 0.8

EEC 0.0002 RQ 22.2For ground applications (Table 16)' the LOC is not exceeded for non-listed plant species. The listed species LOC is exceeded out to 500 

### ft when the default (fine) droplet size is modeled. Using the medium-coarse droplet-size spectrum reduces the LOC exceedance to less than 300 

### ft from the treated field. -- - 700' 900'

Table 

### 16. RQs for listed and non-listed plants at specified distance from application site using a ground application of florasulam with various droplet-size spectra based on AgDRIFT EECs and the vegetative vigor endpoints. 

## [ Droplet Size Spectrum (ASAE S572) aboldindicates exceeds LOC 0.000066 0.000056



## I I Non-listed 

## I Listed 

## I Listed 

## I 7.3 6.2

"boldindicates exceeds LOC

Distance

Because the proposed florasulam label identifies a potential for the chemical to reach groundwater, potential risk to other crops irrigated with contaminated groundwater was considered. Thehighest modeled groundwater concentrations (from the Drinking Water Assessment, D332069), 0.0135 ng/L, assuming 1 acre-inch of water, converts to an application rate of 3~10-~ lbs ai/A (Appendix VI). Using the most sensitive endpoint from the vegetative vigor study, the resulting RQ would be 0.0001 7; thus, risk to non-target crops from irrigation with contaminated groundwater appears to be low. Irrigation with surface water contaminated with florasulam at the EEC derived from GENEEC (0.202 ppb; see Aquatic Exposure) results in an RQ for sensitiveplant species of 2.6. Should undiluted irrigation return flow containing the modeled concentration of florasulam be used to irrigate sensitive crop species, there is a potential for crop damage. However, due to the conservative nature of the model and common agricultural practices regarding the target crops, irrigation with contaminated surface water is not likely. 0.00003 0.000026

The PMRA assessment, from which this assessment draws support, uses visual phytotoxicity ratings as the most sensitive endpoints for terrestrial plant species. EFED uses visual ratings qualitatively for characterization, but not for RQ calculation. Risk estimation isbased on growth, or occasionally survival, endpoints. Because visual signs ofphytotoxicity are commonly apparent at lower treatment rates than growth or survival endpoints, the PMRA assessment uses lower EC25 and NOEC values in their assessment. Their assessment uses a vegetative vigor EQs of 0.00002 lbs ai/A (tomato) and an undefined NOEC of<0.00001 lbs ai/A (converted from 0.02 and <0.014 g ailha, respectively). Were non-listed plant RQs to be calculated with the visual phytotoxicity endpoint, the drift-only RQs for dicots would increase to 2.25 for ground application (up from 0.90) and 11.25 for aerial application (up from 4.5), while the listed species RQs would be undefined. 37 of 44 Fine-Medium EEC 

# I RQ 

### 3.3 

### 2.9

Fine-Medium EEC 

# I RQ 0.000018 0.000014

Medium-Coarse

EEC 

# I RQ 

### 2.0 1.6While the PMRA assessment also uses lower endpoints for the seedling emergence study, RQs calculated with those endpoints are well below the LOC. 

### Endocrine Disruption Screening The EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to determine whether certain substances (including all pesticide active and other ingredients) 

### "may have an effect in humans that is similar to an effectproduced by a naturally occurring estrogen, or other such endocrine effects as the Administrator may designate." Following the recommendations of its EndocrineDisruptor Screeningand Testing Advisory Committee (EDSTAC), EPA determinedthat there was scientific basis for including, as part of the program, the androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC's recommendationthat the Program include evaluations of potential effects in wildlife. For pesticide chemicals,EPA will use FIFRA and, to the extent that effects in wildlife may help determine whether a substance may have an effect in humans, FFDCA authority to require the wildlife evaluations. As the science develops and resources allow, screening of additional hormone systems may be added to the Endocrine Disruptor ScreeningProgram (EDSP). When the appropriate screeningandlor testing protocols being considered under the Agency's EDSP have been developed, florasulammay be subjected to additional screening and/or testing to better characterize effects related to endocrine disruption. Based on the available data, there are no indicationsthat exposure to florasulam results in any effect on endocrine-mediated processes.

C. Uncertainties and Data Gaps


### Environmental Fate Database The environmental fate database is relatively complete and constitutes a strong point in this assessment, as both the degradation (type and rate) and mobility of the pesticide have been well established. Acceptable studies have been submitted for hydrolysis, photolysis (aqueous and on soil), aquatic metabolism (anaerobicand aerobic), mobility in soil, and terrestrial field dissipation (one site). Although multiple aerobic soil metabolism studieswere submitted, each was classified "supplemental" (with the exception of one classified "not acceptable"). The single aerobic soil metabolism study conducted with U.S. soils was classified "not acceptable;" none of the supplemental studies were conducted with U.S. soils. Because the parent degrades fairly rapidly, additional data for use in determining the half-life of the parent would not be likely to significantly decrease the uncertainty of the exposure assessment. However, additional aerobic soil metabolism data would add to the available information on the degradates, as the submitted studies were incomplete in that respect. Terrestrial field dissipation data were submitted from only one U.S. site. Although data for multiple foreign field sites were submitted, those studies were classified "supplemental" partially because the depth of samplingwas insufficient to show the extent of leaching that may occur in the field for both the parent and 5-OH-XDE-570. Although the field dissipation studies conducted in the past were not necessarily designed to show the extent of leaching, newer guidelines allow for 38 of44separate modules to help distinguishbetween routes of dissipation such as leaching or runoff. For a cereal grains use, which covers a wide geographic area, data from additional

### U.S. sites would decrease the uncertainty inherent in using data from a single location to determine terrestrial dissipation rates. Environmental Effects The environmental effects database is largely complete and the effects on guideline taxa of exposure to the active ingredient the pesticide have been established. Additional data regarding degradates and formulation toxicity have been submitted. As discussed in the Risk Description, the seedlingemergence study was highly variable which likely contributed to a lack of statisticalpower, adding uncertainty to the seedling emergence endpoints. The uncertainty is not thought to appreciably change the risk conclusions. There appearsto be a range of sensitivitiesto florasulam across the plant species tested. While the guideline vegetativevigor study demonstrates variable sensitivity across a diverse set of species, the two Paterson et al. papers on efficacy show up to five-fold sensitivity within the species field poppies and over a three-fold difference in sensitivity within the weed species G. aparine. Neither species was more sensitivethan the most sensitive species in the vegetative vigor study, as the studies were based on the EC8O. However, if the same variabilityin sensitivityis present in other species, it is possible that the endpointsused in this risk assessment do not represent the most sensitive ECZ5 values of the species tested. The toxicity of the degradates, especially5-OH-XDE-570,to aquatic and terrestrial vascular plants is uncertain. Given that the parent is short-lived, the application rate is low, only one application is needed per season, and that the label has appreciable crop rotation restrictions, there maybe herbicidal activity for longerthan is suggested by fate properties ofthe parent alone. While submitted data indicate 5-OH-XDE-570 is less phytotoxic to unicellular algae than the parent, the parent is also less phytotoxic to unicellular algaethan it is to Lemna gibba. There are no data submitted regarding the phytotoxicity of 5-OH-XDE-570to terrestrial plants. Data submitted regarding the phytotoxicity of 5-OH-XDE-570 would reduce some of the uncertainty in this assessment. Although synergistic effects of tank mixes of active ingredients are not typically evaluated, it is possible that florasulam can exhibit greaterphytotoxicity mixed with other herbicides than that evaluated in this assessment. Three ofthe four labelsproposed for registration are for formulations containing other herbicides, and tank mixing is allowed on all the labels. In a patent application for an unrelated herbicide 

### (US Patent 62971 97), Dow AgroSciences LLC states that one of the preferred tank mix chemicals for their new product is florasulam because there maybe synergistic effects (httv://www.~atentstorm.us/~atents/6297 197-descriwtion.html;accessed 04.19.2007). General This assessment assumes one growing seasonper year, based on common agricultural practices. However, the number of growing seasonsper year is not limited by the label; areas with multiple growing seasons could result in greater exposures on an annual basis. 39 of44IV. CONCLUSION
This baseline risk assessment for the proposed use of florasulam on cereal grains indicates potential risk to terrestrial plants. There is a low potential for directrisk to aquatic plants, and aquatic and terrestrial animals,but there is a potential for indirect effects on these taxa based on florasulam's potential effect on primary productivity and habitat.

V. THREATENEDAND ENDANGERED SPECIES
Levels of concern for threatened and endangered species are exceeded for terrestrial plants. Exceedance of LOCs for plants indicates concern for indirect effects on Federally-listed terrestrial animal species reliant on susceptibleplant populations or communities, or those solely dependent on a sensitive plant for some portion of their life cycle (obligate relationships). The Overview of Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency (USEPA 2004, the 'Overview Document') discusses methods for providing the U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS), collectively 'the Services,' with additional information regarding the listed animal species acute levels of concern (LOCs). A tool has been developedby EFED in consultation with the Services to evaluate the chance of an individual organism being affected given the toxicity of the chemical to the organism and the dose-response curve (see Appendix VII for more detail). For the present time, the Excel spreadsheettool IEC vl.1 allows for such calculations by entering the mean slope estimate and the 95 percent confidence bounds ofthat estimate as the slope parameter for the spreadsheet. In cases where dose-response curves are unavailable, event probabilities are calculated for the listed speciesLOC based on a default slope assumption of 4.5 as per original Agency assumptions oftypical slope cited in Urban and Cook (1986).
The only animal toxicity studyused in this risk assessmentthat reports mortality is the acute avian oral study. Since the only other mortalitywas observed in the acute oral bee study, which is not quantitatively evaluatedby the Agency at this time, IEC modelingwas only done for birds. For birds, the acute risk to listed speciesLOC is 0.1. The chance of one individual being affected at an 

### RQ equal to the LOC is 1 in 294,000 (assuming the default slope). Forbirds, the highest acute 

### RQ in this assessment is 0.0016, for small-sized birds foraging on short grass. If listed birds are as sensitive to florasulam as the endpointused in the model indicates, and exposed to the concentration modeled, the chance of an individual being affected is approximately 1 in 7.5~10"' or less. The screening-level risk assessment indicatesthat the acuterisk LOC for terrestrial plants is exceeded. The Agency considers this to be indicative of a potential for adverse effects to those listed species that rely either on a specificplant species (plant species obligate) or multiple plant species (plant dependant) for some important aspect oftheir life cycle (indirect effects). Indirect effects may include general habitat modification,host plant loss, and food supply disruption. Further analysis regarding the overlap of individual specieswith each use site is required prior to determining the likelihood ofpotential impact to listed species. Such a refinement is outlined in the following sections. 40 of 44A. Action Area For listed species assessmentpurposes, the action area is considered to be the area affected directly or indirectly by the Federal action and not merely the immediate area involved in the action. At the initial screening level, the risk assessment considers broadly described taxonomic groups and so conservatively assumesthat listed species within those broad groups are co-located with the pesticide treatment area. This means that terrestrial plants and wildlife are assumed to be located on or adjacent to the treated site and aquatic organisms are assumed to be located in a surface water body adjacent to the treated site. The assessment also assumes that the listed species are located within an assumed area, which has the relatively highest potential exposure to the pesticide, and that exposures are likely to decrease with distance from the treatment area.
Ifthe assumptions associated with the screening-level action area result in RQs that are below the listed species LOCs, a "no effect" determination conclusion could be made with respect to listed species in that taxa, and no furtherrefinement of the action area is necessary. Furthermore, RQs below the listed species LOCs for a given taxonomic group indicateno concern for indirect effects upon listed species that depend upon the taxonomic group covered by the RQ as a resource. However, in situations where the screening assumptionslead to RQs in excess of the listed species LOCs for a given taxonomic group, a "may affect" designation cannot be precluded and may be associated with direct effects on listed species belongingto that taxonomic group or may extend to indirect effects upon listed speciesthat depend upon that taxonomic group as a resource. In such cases, additional information on the biology of listed species, the locations of these species, and the locations of use sites need to be considered along with available information on the fate and transport properties of the pesticide to determine the extent to which screening assumptions regarding 

### an action area applyto a particular listed organism. These subsequent refinement steps could delineate how this informationwould impact the action area for a particular listed organism and may potentially include areas of exposurethat are downwind and downstreamofthe pesticide use site. B. Taxonomic Groups Potentiallyat Risk The RQs calculatedbased on the ratio of EECs to toxicity endpoints, in this case the NOAEC from terrestrialplant toxicity studies, exceed the LOC. Should estimated exposure levels occur in proximity to listed resources, direct risk to listed plant species and indirect effects on animal species (aquatic and terrestrial; Table 17) is possible. Appendix 

### VIII provides a tabulation of species for each taxon that maybe affected by this action. This Level 

### I screening assessment is based on the initial assumptionthat listed species within the taxonomic groups of concern are actually present in areas for which the estimated exposure levelsused for RQ calculation can be expected to occur. A specific determination of "may affect" for any RQ in excess of listed species LOCs cannot be made until a determinationofthe co-occurrence of the listed species with the action area has been determined. This was not done for this assessment. Table 17. Listed species risks associated with potential direct or indirect effects from to the proposed use of florasulam on cereal grains. Listed Taxon Terrestrial and semi-aquatic plants - monocots Direct Effects Acute

Yes Direct Effects Chronic yes1 Indirect EffectsTerrestrial and semi-aquatic Yes plants - dicots 

# I

Insects

Birds Terrestrial-phase amphibians Reptiles
Mammals Aquatic plants

Freshwater fish

modification,host plant loss, and food supply disruption. No

No

No

Aquatic-phase amphibians
Freshwater invertebrates
Mollusks

Marinelestuarinefish

Marinelestuarinecrustaceans



### C. Indirect Effects Analysis No

No

No

No

Because terrestrialplant RQs are aboverisk to non-endangered speciesLOCs, the Agency considers this to be indicative of a potential for adverse effects to those listed species that are plant species obligates or plant dependant for some important aspect of their life cycle. The extent to that the new uses of florasulamwill indirectlyaffect listed animal specieswill require identification of listed species that co-occur in areas of florasularn use and an evaluation of critical habit as described below. Because of the potential extent of the use of florasulam,

### EFED cannot preclude the possibility of a 'may affect' designation for listed speciesbased on this assessment. No

No



### onli listed LOC exceeded for terrestrialplants, therefore there is potential for adverse effects to those species that rely either on a specific plant species or multipleplant species. Plant indirect effectsmay include general habitat No

No

No

No

No



### D. Critical Habitat yes' yes' yes'

No

No

No

No

The screening-levelrisk assessment has identifiedpotential concerns for direct and indirect effects on listed species associated with action areas where florasularn is used. In light ofthe potential for effects on listed species, the next step for EPA and the Services is to identi@ which listed species and critical habitat are potentially implicated. Analytically, the identification of such species and critical habitat can occur in either of two ways. First, the agencies could determine whether the action area overlaps critical habitat or the occupied range of each listed species. If so, 42 of44 - yes' yes' yes' yes'

No

No

No

No

No yes' yes' yes' yes' yes'EPA would examine the potential impact of the use of florasulam on listed species and whether impacts on non-endangered specieswould affect the listed species indirectly or directly affect a constituent element of the critical habitat. Then EPA would determine whether use of the pesticide overlaps the critical habitat or the occupied range of those listed species. At present, the information reviewedby EPA does not permit use of either analytical approach to make a definitive identification of speciesthat are potentiallyimpacted indirectlyor critical habitats that are potentially impacted directly by the use of the pesticide. EPA and the Serviceswill work together to conduct the necessary analysis. 

### E. Co-occurrence Analysis The goal of the analysis for co-location is to determinewhether sites ofpesticide use are geographically associatedwith known locations of listed species. At the screening level, this analysis is accomplished using the Agency's LOCATES (v. 2.10.3) database. The database uses location information for listed species at the county level and compares it to agricultural census data for crop production at the same county level of resolution. The database contains Federally-listed species that are located within statesknown to produce the crop upon which the pesticide will be used. Because the Level-I screeningassessment considers

### both direct and indirect effects across generic taxonomic groupings, it is not possible to exclude any taxonomic group from a LOCATES database query for a screening-levelrisk assessment. Because the registration of florasulam would be the first in the U.S., the extent of its potential use has not yet been determined. As noted previously, at the screening level, it is not possible to evaluate all the potential direct and indirect effectsthat could impact endangered animals. Therefore, a 'may affect' designationcannot be precluded for listed animals based on this assessment.

### VI.

### REFERENCES
Fairchild 

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### Environ. Toxicol. Chem. 13: 1383-1391. Hoerger, F. and E.E. Kenaga. 1972. Pesticide residues on plants: correlation ofrepresentative data as a basis for estimation oftheir magnitude in the environment. 

### Environmental Quality and Safety. 1:9-28.
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### http://www.nass.usda.gov/Census~~f~Agriculture/index.asp. Accessed on March 3,2007. Urban D.J. and N.J. Cook. 1986. Hazard Evaluation Division Standard Evaluation Procedure Ecological Risk Assessment. EPA 54019-85-001.U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC.
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### http://www.epa.gov/oppefed1/models/water/input_guidance2~28~02.htm/.
USEPA. 2004. Overview of Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency. Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington, DC.
USEPA. 2006. Water Models. U.S. Environmental Protection Agency, Pesticides: Science and Policy. Last updated May 2,2006. Online at: 

### http://www.epa.gov/oppefedl/models/water/. Willis, Guye 

### H., and Les1ie.L. McDowell. 1987. Pesticide Persistence on Foliage. in 

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