Naptalam and Naptalam Sodium Reregistration Ecological Risk Assessment Prepared by:

Michelle Embry, Biologist Dana Spatz, Chemist United States Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division Environmental Risk Branch 2 1200 Pennsylvania Avenue, N. W. Mail Code 7507C Washington, DC 20460 Reviewed by:

Thomas Bailey, Ph. D Chief, Environmental Risk Branch 2  ii Table of Contents I. EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1 A. Potential Risks to Non target Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1 1. Nature of Chemical Stressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1 2. Exposure Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  2 3. Effects Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  2

II. PROBLEM FORMULATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 A. Stressor Source and Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 1. Chemical and Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 2. Mode of Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 3. Overview of Pesticide Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 B. Assessment Endpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 1. Ecosystems Potentially at Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4 2. Ecological Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4 C. Conceptual Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6 1. Risk Hypotheses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6 2. Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  7 D. Analysis Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9 1. Key Uncertainties and Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9 2. Measures of Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9 3. Measures of Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  9 4. Measures of Ecosystem and Receptor Characteristics . . . . . . . . . . . . . . . . . . . . . . .  9

III. ANALYSIS PHASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12 A. Use Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12 B. Exposure Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12 1. Environmental Fate and Transport Characterization . . . . . . . . . . . . . . . . . . . . . . .  12 2. Aquatic Resource Exposure Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14 a. Aquatic Organism Exposure Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . .  14 b. Aquatic Organism Exposure Monitoring ( Field Data) . . . . . . . . . . . . . . . .  16 3. Terrestrial Organism Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16 4. Non target Plant Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 C. Ecological Effects Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 1. Aquatic Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 a. Aquatic Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 b. Aquatic Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19 2. Terrestrial Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20 a. Terrestrial Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20 b. Terrestrial Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  21

IV. RISK CHARACTERIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  21 A. Risk Estimation   Integration of Exposure and Effects Data . . . . . . . . . . . . . . . . . . . . . . .  21 1. Non target Aquatic Animals and Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22 2. Non target Terrestrial Animals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22 3. Avian Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22  iii 4. Non target Terrestrial and Semi aquatic Plants . . . . . . . . . . . . . . . . . . . . . . . . . . .  23 5. Freshwater Fish and Invertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23 6. Mammals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24 B. Risk Description   Interpretation of Direct Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27 1. Risks to Aquatic Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27 2. Risks to Terrestrial Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27 3. Review of Incident Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28 4. Endocrine Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28 5. Threatened and Endangered Species Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . .  29 a. Taxonomic Groups Potentially at Risk . . . . . . . . . . . . . . . . . . . . . . . . . . .  29 b. Probit Slope Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30 c. Critical Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  31 d. Indirect Effect Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  31 C. Description of Assumptions, Uncertainties, Strengths, and Limitations . . . . . . . . . . . . . . .  32

V. Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34

Appendices APPENDIX A. Environmental Fate Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  A 1

APPENDIX B. Aquatic Exposure Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  B 1

APPENDIX C. Terrestrial Exposure Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  C 1

APPENDIX D. TerrPlant Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  D 1

APPENDIX E. Ecological Effects Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  E 1

APPENDIX F. The Risk Quotient Method and Levels of Concern . . . . . . . . . . . . . . . . . . . . . . . . . .  F 1

APPENDIX G. Summary of Threatened and Endangered Species . . . . . . . . . . . . . . . . . . . . . . . . . .  G 1

APPENDIX H. Data Requirements Tables   Environmental Fate and Effects . . . . . . . . . . . . . . . . .  H 1  1 I. EXECUTIVE SUMMARY A. Potential Risks to Non target Organisms A Tier 1 screening level risk assessment focusing on maximum proposed uses of naptalam on curcubits ( cucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba) and ornamental woody plant stock suggests that concentrations of naptalam in the environment, when compared with minimum toxicity values, are unlikely to result in acute adverse effects to freshwater aquatic organisms. Insufficient toxicity data are available to characterize the risk of chronic adverse effects to freshwater organisms and no data are available to characterize the risk to estuarine/ marine fish and invertebrates. Risks to terrestrial species may occur and are summarized below.

° The exposure to naptalam sodium salt on short grass, tall grass, broadleaf plants, and small insects from curcubit application exceeds the endangered species and acute restricted use levels of concern ( LOC) for maximum residue conditions for 15 and 35 gram mammals. Additionally, the acute risk LOC is exceeded for 15g mammals that feed on short grass. The acute restricted use LOC is exceeded for mean residue conditions for 15 and 35 gram mammals that feed on short grass.

° The exposure to naptalam sodium salt on short grass, tall grass, broadleaf plants, and small insects resulting from ornamental woody plant application exceeds endangered species and acute restricted use levels of concern for maximum residue conditions for 15 and 35 gram mammals, and for 1000 gram mammals on short grass. Additionally, the acute LOC is exceeded for 15 and 35 gram mammals based on maximum residues on short grass, broadleaf plants, and small insects. Exposure to naptalam on short grass, broadleaf plants, and small insects for 15 and 35 gram mammals from ornamental woody plant application also exceeds the endangered species levels of concern for mean residue conditions.

° Chronic exposure to naptalam from curcubit application on short grass for maximum residue conditions poses a chronic risk to wild mammals ( RQ = 1.74).

° Chronic exposure to naptalam from ornamental woody plant application exceeded the LOC based on maximum residue conditions on short grass, tall grass, broadleaf plants, and small insects. Additionally, the LOC is exceeded based on mean residue conditions on short grass.

The naptalam acid is practically non toxic to mammalian species. Due to its environmental fate properties, it is assumed that most of the naptalam sodium salt will dissociate at environmental pH levels to form the non toxic naptalam acid and sodium cations. It is therefore possible that the naptalam sodium salt acute endpoint ( 1,700 mg/ kg bw) overestimates risk, due to the fact that very little of this chemical will persist in the environment long enough to lead to mammalian exposure.

1. Nature of Chemical Stressor Naptalam ( CAS number 132 66 1; 132 67 2 [ naptalam sodium]) is a soil acting herbicide that controls broadleaf weeds at germination and early growth stage. It is absorbed by seeds and primary roots and  2 interferes with normal growth. Naptalam exhibits minimal foliar activity and minimal activity on grassy weeds. This report focused on assessing and characterizing potential risks resulting from the agricultural uses of naptalam on cucumber, watermelon, honeydew, and cantaloupe.

2. Exposure Characterization Conclusions The environmental fate and mobility of naptalam is pH dependent. Naptalam is formulated as a sodium salt and predominantly exists as an anion in the environment. Based on the pKa ( 4.6), naptalam sodium salt will dissociate under most environmental conditions and the predominant species will be the naptalam acid. Anions often possess high mobility in soils, tend to have significant leaching potential and will not volatilize from water or soil surfaces. The hydrolysis of naptalam appears to occur slowly under alkaline and neutral conditions but proceeds rapidly under acidic conditions with a half life on the order of a few days. Biodegradation appears to be insignificant under anaerobic conditions, but may be an important environmental fate process in soil and water under aerobic conditions. A major degradation product of naptalam is 1 naphthylamine which has been classified as a carcinogen by the Occupational Safety and Health Administration ( OSHA).

3. Effects Characterization Conclusions Results of acute toxicity studies suggest that naptalam is practically non toxic to freshwater fish and invertebrates. No chronic toxicity data were submitted for freshwater organisms and no acute or chronic testing of estuarine/ marine fish or invertebrates was submitted.

Naptalam sodium salt is categorized as slightly toxic to small mammals on an acute oral basis and the potential for chronic reproductive effects appears to be low, whereas naptalam acid is practically non toxic to mammalian species on an acute oral basis. Results of acute oral toxicity studies suggest that naptalam is practically non toxic to birds. Results of reproductive studies of naptalam in birds are not available. Based on contact LD50 studies for the honey bee ( Apis mellifera), naptalam is classified as practically nontoxic on an acute contact basis.

Because naptalam is an herbicide, it is anticipated that non target plants may be particularly susceptible to adverse effects; however, no data were submitted to assess the toxicity of naptalam toward aquatic or terrestrial non target plants.  3 II. PROBLEM FORMULATION A. Stressor Source and Distribution 1. Chemical and Physical Properties Naptalam is formulated as a sodium salt in order to increase its solubility. Based on the pKa ( 4.6), the salt will dissociate under most environmental conditions and the predominant species will be the naptalam acid. Therefore, naptalam will exist primarily as an anion in water and moist soils. Since the vapor pressure and Henry's law constant of anions are infinitesimally small, no volatilization from soil or water surfaces will occur. Anions tend to have much greater mobility in soils than neutral species or cations; therefore, it is expected that naptalam will be highly mobile and may have the potential to leach into groundwater. Hydrolysis occurs in a matter of a few days under acidic conditions, in distilled water, but metal ions that are ubiquitous in natural waters tend to retard the rate of hydrolysis. Photolysis and biodegradation under aerobic conditions also occur in a matter of days to a few weeks, however under anaerobic conditions naptalam appears to be stable.

The naptalam acid is practically non toxic to mammalian species, and due to its environmental fate properties, it is assumed that most of the naptalam sodium salt will dissociate at environmental pH levels to form the non toxic naptalam acid and sodium cations. It is therefore possible that the naptalam sodium salt acute endpoint ( 1,700 mg/ kg bw) overestimates risk, due to the fact that very little of this chemical will persist in the environment long enough to lead to mammalian exposure.

2. Mode of Action Naptalam is a selective herbicide absorbed predominantly by the roots, but also to some extent by the foliage, with accumulation in the meristematic tissue. It works by inhibiting seed germination and IAA transport.

3. Overview of Pesticide Usage Naptalam use is largely limited to the eastern region of the United States with its highest use in the southeastern states particularly in Florida and Georgia. It is most frequently applied to cucumber and watermelon, but has also been used as a selective herbicide in honeydew and cantaloupe. It has additional uses on ornamental woody plant nursery stock.

B. Assessment Endpoints Assessment endpoints are defined as " explicit expressions of the actual environmental value that is to be protected." Defining an assessment endpoint involves two steps: 1) identifying the valued attributes of the environment that are considered to be at risk; and 2) operationally defining the assessment endpoint in terms of an ecological entity ( i. e., a community of fish and aquatic invertebrates) and its attributes ( i. e., survival and reproduction). Therefore, selection of the assessment endpoints is based on valued entities ( i. e., ecological receptors), the ecosystems potentially at risk, the migration pathways of pesticides, and the routes by which ecological receptors are exposed to pesticide related contamination. 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.  4 1. Ecosystems Potentially at Risk Ecosystems potentially at risk are expressed in terms of the selected assessment endpoints. The typical assessment endpoints for screening level pesticide ecological risks are reduced survival, and reproductive and growth impairment for both aquatic and terrestrial animal species. Aquatic animal species of potential concern include freshwater fish and invertebrates, estuarine/ marine fish and invertebrates, and amphibians. Terrestrial animal species of potential concern include birds, mammals, beneficial insects, and earthworms. For both aquatic and terrestrial animal species, direct acute and direct chronic exposures are considered. In order to protect threatened and endangered species, all assessment endpoints are measured at the individual level. Although all endpoints are measured at the individual level, they provide insight about risks at higher levels of biological organization ( e. g. populations and communities). For example, pesticide effects on individual survivorship have important implications for both population rates of increase and habitat carrying capacity.

For terrestrial and semi aquatic plants, the screening assessment endpoint is the perpetuation of populations of non target species ( crops and non crop plant species). Existing testing requirements have the capacity to evaluate emergence of seedlings and vegetative vigor. Although it is recognized that the endpoints of seedling emergence and vegetative vigor may not address all terrestrial and semi aquatic plant life cycle components, it is assumed that impacts at emergence and in active growth have the potential to impact individual competitive ability and reproductive success.

For aquatic plants, the assessment endpoint is the maintenance and growth of standing crop or biomass. Measurement endpoints for this assessment endpoint focus on algal and vascular plant ( i. e., duckweed) growth rates and biomass measurements.

The ecological relevance of selecting the above mentioned assessment endpoints is as follows: 1) complete exposure pathways exist for these receptors; 2) the receptors may be potentially sensitive to pesticides in affected media and in residues on plants, seeds, and insects; and 3) the receptors could potentially inhabit areas where pesticides are applied, or areas where runoff and/ or spray drift may impact the sites because suitable habitat is available.

2. Ecological Effects Table 1 gives examples of taxonomic groups and test species evaluated for ecological effects in screening level risk assessments.  5 Table 1. Taxonomic groups and test species evaluated for ecological effects in screening level risk assessments.

Taxonomic group Example( s) of representative species Birdsa Mallard duck ( Anus playtrhynchos) Bobwhite quail ( Colinus virginianus)

Mammals Laboratory rat Freshwater fishb Bluegill sunfish ( Lopomis macrochirus) Rainbow trout ( Oncorhynchus mykiss)

Freshwater invertebrates Water flea ( Daphnia magna)

Estuarine/ marine fish Sheepshead minnow ( Cypridodon variegatus)

Estuarine/ marine invertebrates Eastern Oyster ( Crassostrea virginica) Mysid Shrimp ( Americamysis bahia)

Terrestrial plantsc Monocots   corn ( Zea mays) Dicots   soybean ( Glycine max)

Aquatic plants and algae Duckweed ( Lemna gibba) Green algae ( Selenastrum capricornutum)

aBirds may be surrogates for amphibians ( terrestrial phase) and reptiles. bFreshwater fish may be surrogates for amphibians ( aquatic phase). cFour species of two families of monocots, of which one is corn; six species of at least four dicot families, of which one is soybeans.

Within each of these very broad taxonomic groups, an acute and/ or chronic endpoint is selected from the available test data. Additional ecological effects data for naptalam are available for honey bees ( Apis mellifera) and have been incorporated into the risk characterization as an additional line of evidence. Studies on acute toxicity to plants that were classified as invalid were not included in the risk characterization.

A complete discussion of all toxicity data available for this risk assessment and the resulting measurement endpoints selected for each taxonomic group are included in Appendix E. A summary of the assessment and measurement endpoints selected to characterize potential ecological risks associated with exposure to naptalam is provided in Table 2.  6 Table 2. Summary of assessment and measurement endpoints.

Assessment Endpoint Measurement Endpoint 1. Abundance ( i. e., survival, reproduction, and growth) of individuals and populations of birds. 1a. Bobwhite quail acute oral LD50. 1b. Bobwhite quail and mallard duck subacute dietary LD50. 1c. Bobwhite quail and mallard duck chronic reproduction NOAEC and LOAEC.

2. Abundance ( i. e., survival, reproduction, and growth) of individuals and populations of mammals. 2a. Laboratory rat acute oral LD50. 2b. Laboratory rat developmental and chronic NOAEC and LOAEC.

3. Survival and reproduction of individuals and communities of freshwater fish and invertebrates. 3a. Rainbow trout and bluegill sunfish acute LC50. 3b. Rainbow trout chronic ( early life) NOAEC and LOAEC. 3c. Water flea ( and other freshwater invertebrates) acute EC50. 3d. Water flea chronic ( life cycle) NOAEC and LOAEC.

4. Survival and reproduction of individuals and communities of estuarine/ marine fish and invertebrates. 4a. Sheepshead minnow acute LC50. 4b. Estimated chronic NOAEC and LOAEC values based on the acute to chronic ratio for freshwater fish. 4c. Eastern oyster and mysid shrimp acute LC50. 4d. Mysid shrimp chronic ( life cycle) NOAEC and LOAEC. 4e. Estimated NOAEC and LOAEC values for mollusks based on the acute to chronic ratio for mysids.

5. Perpetuation of individuals and populations of non target terrestrial and semi aquatic species ( crops and non crop plant species). 5a. Monocot and dicot seedling emergence and vegetative vigor EC25 values.

6. Survival of beneficial insect populations. 6a. Honeybee acute contact LD50.

7. Abundance ( i. e., survival, reproduction, and growth) of earthworm populations. 7a. Acute and subchronic earthworm LC50 values.

8. Maintenance and growth of individuals and populations of aquatic plants from standing crop or biomass. 8a. Algal and vascular plant ( i. e., duckweed) EC50 values for growth rate and biomass measurements.

LD50 = Lethal dose to 50% of the test population. NOAEC = No observed adverse effect level. LOAEC = Lowest observed adverse effect level. LC50 = Lethal concentration to 50% of the test population. EC50/ EC25 = Effect concentration to 50/ 25% of the test population.

C. Conceptual Model 1. Risk Hypotheses In order for a chemical to pose an ecological risk, it must reach ecological receptors in biologically  7 significant concentrations. An exposure pathway is the means by which a contaminant moves in the environment from a source to an ecological receptor. For an ecological exposure pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure. In addition, the potential mechanisms of transformation ( i. e., which degradates may form in the environment, in which media, and how much) must be known, especially for a chemical whose metabolites/ degradates are of greater toxicological concern. The assessment of ecological exposure pathways, therefore, includes an examination of the source and potential migration pathways for constituents, and the determination of potential exposure routes ( e. g., ingestion, inhalation, dermal absorption).

Ecological receptors that may potentially be exposed to naptalam and its degradates include terrestrial and semi aquatic wildlife ( i. e., mammals, birds, and reptiles), terrestrial and semi aquatic plants, and soil invertebrates. In addition to terrestrial ecological receptors, aquatic receptors ( e. g., freshwater and estuarine/ marine fish and invertebrates, and amphibians) may also be exposed to potential migration of pesticides from the site of application to various watersheds and other aquatic environments via runoff and spray drift.

2. Diagram The conceptual site model shown in Figure 1 generically depicts the potential source of naptalam, release mechanisms, abiotic receiving media, biological receptor types, and effects endpoints of potential concern.  8 Source: spray on several crops, spray drift, and runoff Potential Exposure: runoff, drift, residue in the water column, sediments and/ or pore water Potential Exposure: shortgrass, tallgrass, forage, small insects Receptor: freshwater and estuarine/ marine fish and invertebrates Receptor: small mammals, birds Predicted Effects ( Direct): acute morbidity and chronic effects on growth, development, and reproduction 1) Possible effects to recreational fisheries 2) Possible effects to aquatic population 3) Possible effects to commercial aquaculture Predicted Effects ( Indirect): food chain alterations that could affect fish populations Predicted Effects: acute morbidity, chronic effects on growth, development, and reproduction Figure 1. General conceptual model for a screening level ecological risk assessment.  9 D. Analysis Plan 1. Key Uncertainties and Data Gaps The adequacy of the submitted data was evaluated relative to Agency guidelines. The following identified data gaps for environmental fate and toxicity endpoints result in a degree of uncertainty in evaluating the ecological risk of naptalam.

° Hydrolysis half lives are not available at neutral and alkaline pH levels. However, no degradation was observed in the dark control for the aqueous photolysis study conducted at pH 7. Therefore, stability to hydrolysis is assumed at neutral pH.

° No data are available to assess the acute or chronic risk of naptalam to estuarine/ marine fish and invertebrates.

° No data are available to assess the chronic risk of naptalam to freshwater fish and invertebrates and aquatic and terrestrial plants.

° No data are available on the potential for naptalam to bioaccumulate in fish. Given the very high log Kow, we expect that naptalam, once dissociated, will accumulate in fish tissue.

2. Measures of Exposure Exposure concentrations for aquatic ecosystems assessments were estimated based on EFED's aquatic Tier I model GENEEC Version 2.0 ( GENEEC2, 2001). This program uses the soil/ water partition coefficient and degradation kinetic data to estimate runoff from a ten hectare field into a one hectare by two meter deep ` standard' pond. This Tier I model was designed as a screen and estimates protective pesticide concentrations in surface water from a few basic chemical parameters and pesticide label use and application information. Residues in potential dietary sources for mammals and birds ( e. g., vegetation, insects) were estimated using the conceptual approach given in the Tier 1 model ELL FATE Version 1.4 ( ELL FATE, 2004).

3. Measures of Effect Measures of effect are generally based on the results of a toxicity study, although monitoring data may also be used to provide supporting lines of evidence for the risk characterization. A complete summary of the measures of effect based on toxicity studies for different ecological receptors and effect endpoints ( acute/ chronic) is given in Table 2. Examples of measures of acute effects ( e. g., lethality) include an oral LD50 for mammals and LC50 for fish and invertebrates. Examples of measures of chronic effects include a NOAEL for birds or mammals based on reproduction or developmental endpoints, and an EC50 for plants based on growth rate or biomass measurements.

4. Measures of Ecosystem and Receptor Characteristics For the Tier 1 assessment using GENEEC2 and ELL FATE, the ecosystems that are modeled are intended to be generally representative of any aquatic or terrestrial ecosystem associated with areas where naptalam  10 is used. The receptors addressed by the aquatic and terrestrial risk assessments are summarized in Figure 2. For aquatic assessments, generally fish and aquatic invertebrates in both freshwater and estuarine/ marine environments are represented. For terrestrial assessments, three different size classes of small mammals are represented, along with four potential foraging categories ( see Appendix E for a detailed description).  11 Figure 2. Agricultural uses of naptalam in 1992 ( USGS, 2004).  12 III. ANALYSIS PHASE A. Use Characterization The agricultural uses of naptalam in the United States are for watermelon, cucumber, cantaloupe, and honeydew crops. The total amount of naptalam increased from 1992 to 1997 according to data supplied by the National Center for Food and Agricultural Policy Pesticide Use Database and the USGS National Pesticide Use Synthesis project illustrated in Table 3 and Figure 2. The total weight of naptalam applied to watermelon, the crop with the highest naptalam application, increased in 1992 from approximately 88,000 to 97,000 pounds in 1997. Naptalam use is limited to the eastern region of the United States with the highest use in the southeastern states, particularly in Florida and Georgia. Information provided by the registrant ( EFED, 2004), Crompton, describes the highest single application rate of naptalam as 4 lb a. i./ A with a maximum of two applications per season. Applications may occur 2 to 6 weeks between treatments. The highest sales of naptalam in 2003 were in Texas, North Carolina, and Georgia for use on watermelon, cucumber, cantaloupe, and honeydew crops. The average area that is treated with naptalam per season is 23,400 acres, based on registrant data for 2000  2003. Naptalam is also currently approved for use on woody ornamental nursery stock.

Table 3. Agricultural uses of naptalam in 1997 ( NCFAP, 2004).

Crop State ( Top 3) Pounds of naptalam applied per state Total pounds of naptalam applied Watermelon Florida Georgia Texas 37910.0 25011.3 8387.7 97133.2 Cucumber Florida Georgia Michigan 19981.2 13812.0 10398.7 78895.0 Cantaloupe Indiana Colorado Maryland 2235.3 2055.0 1194.0 8387.3 Honeydew Texas 960.9 960.9 B. Exposure Characterization 1. Environmental Fate and Transport Characterization Environmental fate properties of naptalam are shown in Table 4.  13 Table 4. Physical and chemical properties of naptalam.

Property Value Reference Structure ( sodium salt)

CAS number 132 66 1 132 67 2 ( sodium salt)

Pesticide classification Herbicide SMILES notation OC(= O) c1ccccc1C(= O) Nc2cccc3ccccc23 ( naptalam)

[ Na] OC(= O) c1ccccc1C(= O) Nc2cccc3ccc cc23 ( sodium salt)

Molecular weight 291.3 g/ mol ( naptalam) 313.3 g/ mol ( sodium salt) Tomlin, 1997 Tomlin, 1997 Molecular formula C18H13NO3 ( naptalam) C18H12NO3Na ( sodium salt) Tomlin, 1997 Tomlin, 1997 Water solubility ( 20 ° C) 200 mg/ L ( naptalam) 300,000 mg/ L ( sodium salt) 249,000 mg/ L at 25 ° C ( sodium salt) Tomlin, 1997 Tomlin, 1997 Weed Science Society of America, 1994 Dissociation constant ( pKa) 4.6 Tomlin, 1997 Vapor pressure ( 25 ° C) 9.1x10 11 mm Hg EPIWIN Henry's law constant 2.4x10 15 atm m3/ mol EPIWIN log Kow 5.42 ( naptalam)  0.39 ( sodium salt) Tomlin, 1997 EPIWIN Hydrolysis half life pH 5 pH 7 pH 9 2.9 days No data No data MRID 43647701 Na+

 O O O HN Table 4. Physical and chemical properties of naptalam.

Property Value Reference  14 Aqueous photolysis half life 6.2  6.9 days 10.3 days MRID 41385401 MRID 41385401 Soil photolysis half life 15.9 days MRID 41385402 Aerobic soil metabolism half life 36.7 days MRID 41427201 Anaerobic soil half life 246 days MRID 41427202 Adsorption coefficient ( Koc) 20 Weber, 1994 At pH 7, naptalam appears to be stable to chemical hydrolysis based on information from the dark control in the aqueous photolysis study; however, at pH 5 naptalam hydrolyzed with a half life of approximately 3 days. Experiments have shown that metal ions such as copper and zinc may inhibit the rate of hydrolysis, therefore, this reaction may occur more slowly in natural waters and soils than under laboratory conditions using distilled, deionized water. Three degradation products have been observed during the degradation of naptalam : 1 naphthylamine, N( 1 naphthyl) phthalimide, and phthalic acid. Photolysis of naptalam may be an important environmental fate process based on aqueous photolysis half lives in the range of 6.2 to 10.3 days, and a soil photolysis half life of 15.9 days. 1 Naphthylamine and N( 1 naphthyl) phthalimide were observed as degradation products in both aqueous and soil photolysis experiment. Naptalam degraded with a half life of 36.7 days in a sandy loam soil under aerobic conditions. Two non volatile degradates were identified ( N 1 naphthylphtalimide and 1 naphthylamine). Under anaerobic conditions the half life of naptalam is considerably longer ( 246 days).

Naptalam is formulated as a sodium salt in order to increase its solubility. Based on the pKa ( 4.6), the salt will dissociate under most environmental conditions and the predominant species will be the naptalam acid. Therefore, naptalam will exist primarily as an anion in water and moist soils. The high solubility of the sodium salt and a reported Koc value of 20 from the open literature indicates that naptalam may leach into groundwater. Field dissipation experiments submitted to EFED do not satisfy the data requirements of Guideline 164 1 and the results of the submitted experiments have been deemed of uncertain value due to experimental deficiencies.

2. Aquatic Resource Exposure Assessment a. Aquatic Organism Exposure Modeling To determine ecological risks associated with agricultural uses of naptalam, estimated environmental concentrations ( EECs) in surface water were modeled using the Tier I model Generic Estimated Environmental Concentrations ( GENEEC, Version 2.0, dated August 1, 2001). Input parameter values are based on the data presented in Table 5. The product label for ` Alanap' describes an aerial and ground application. Of these two application methods, aerial applications are more likely to yield higher EECs due to the potential for spray drift. Therefore, GENEEC2 was run for aerial applications of naptalam. The peak ( 24 hour), 21 day and 60 day surface water EECs for curcubit application of naptalam are 452.4,  15 442.2, and 423.1 ppb, respectively. The peak ( 24 hour), 21 day and 60 day surface water EECs for ornamental woody plant application of naptalam are 470.7, 460.1, and 440.2 ppb, respectively. Table 6 shows the output of the model.

Table 5. Input parameters for naptalam used in GENEEC2.

Parameter Value Source Crop Cucurbitsa Ornamental woody plants Master label Water solubility ( mg/ L at 25 ° C) 249,000 Weed Science Society of America, 1994 Hydrolysis half life ( days) stable ( at pH 7) MRID 41385401 Aerobic soil metabolism half life ( days) 110b 36.7 days x 3 ( MRID 41427201) USEPA, 2002 Aerobic aquatic metabolism half life ( days) 220 No study; value calculated as 2 x aerobic soil t ½ ( USEPA, 2002)

Aqueous photolysis half life ( days) 6.2 MRID 41385401 Adsorption coefficient ( Koc) c 20 Weber, 1994 Pesticide is wetted in Yes Master label Application method ( for maximum application rate) Aerial Master label Application rate ( lb a. i./ A) Cucurbitsa: 4 Ornamental woody plants: 8 Master label Maximum number of applications per year Cucurbitsa: 2 Ornamental woody plants: 1 Master label Application interval ( days) 14 Master label Depth of incorporation ( cm) 0 Master label aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba. bMRID 00145416 ( 1978) not used in this calculation because of analytical issues and extraction problems. cNo study available on the adsorption/ desorption coefficient ( lowest non sand Kd).  16 Table 6. Summary of crop application scenario and estimated environmental concentrations ( EECs) of naptalam obtained from GENEEC2.

Crop Application rate ( lb a. i./ A) Maximum # of applications EEC ( ppb)

Peak 21 day 60 day Cucurbitsa 4 2 452.4 442.2 423.1 Ornamental woody plants 8 1 470.7 460.1 440.2 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba b. Aquatic Organism Exposure Monitoring ( Field Data)

No data were identified to provide information on aquatic organism monitoring.

3. Terrestrial Organism Exposure The EFED terrestrial exposure model, ELL FATE ( ELL FATE, Version 1.4, dated April 7, 2004), is used to estimate exposures and risks to avian and mammalian species. Input values on avian and mammalian toxicity as well as chemical application and foliar half time data are required to run the model. The model provides estimates of both exposure concentrations and risk quotients ( RQs). Specifically, the model provides estimates of concentrations ( maximum and average) of chemical residues on the surface of different types of foliage that may be sources of exposure to avian, mammalian, reptilian, or terrestrial phase amphibian receptors. The surface residue concentration ( ppm) is estimated by multiplying the application rate ( pounds active ingredient per acre) by a value specific to each food item. These values ( termed the Hoerger Kenaga estimates) along with a more detailed discussion of the methodology implemented by ELL FATE, are presented in Appendix C ( ELL Fate Model and Results).

For multiple applications, the EEC is determined by adding the mass on the surface immediately following the application to the mass of the chemical still present on the surfaces on the day of application ( determined based on first order kinetics using the foliar half life as the rate constant). It should be noted that because the EEC represents the concentration immediately following a direct application, the foliar half life variable is only influential for scenarios involving multiple applications. The following table describes the input values used for estimating avian and mammalian exposure risks to naptalam.

A maximum single application rate of 8 lbs a. i./ A was used ( consistent with currently labeled uses on woody ornamentals), as well as a scenario involving an application rate of 4 lbs a. i./ A, for a maximum of two applications per season with a minimum interval of 14 days for curcubit crops. Although no information was available on the foliar dissipation rate of naptalam, two values were identified from a study of dislodgable foliar residue. The upper 90% confidence interval of the mean of the two values is approximately 4 days. Given the uncertainty in using data from a dislodgable foliar residue study to estimate dissipation rates, two scenarios were considered to explore the plausible range of concentrations. Scenarios were run with a foliar half life of 4 days.  17 A summary of the input parameters used in ELL FATE for each scenario is presented in Table 7. Naptalam concentrations on foliar surfaces ranged from 65  1,920 ppm for conditions of maximum residues and 30  680 ppm for conditions of mean residues. Naptalam concentrations are highest on the surfaces of short grass and lowest on the surfaces of fruits, pods, and large insects. Table 8 shows the EECs of naptalam applied to cucurbits and Table 9 shows the output for ornamental woody crops. A thorough description of the ELL FATE model is provided in Appendix C.

Table 7. Input parameters used in ELL FATE v1.4 to determine terrestrial EECs for naptalam.

Input variable Parameter value Source Maximum application rate Cucurbitsa: 4 lbs a. i./ A Ornamental woody plants: 8 lbs a. i./ A Product label Maximum number of applications per year Cucurbitsa: 2 Ornamental woody plants: 1 Product label Frequency of applicationb 14 days Product label Foliar half life 35 days 4 days ( for cucurbits only) c Default ( ELL FATE, 2004) MRID 44972501, 90% UCL aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba bInterpreted as the interval ( days) between successive applications. For single application scenarios, this variable is set to 0. c90% UCL = 90% upper confidence limit on the mean: t t s n n 1 2 90 1 166 288 2 3 078 0 8267 2 415 / , ( ) ( . . ) ( . . ) . + = + + × =

Table 8. Acute, 24 hour average terrestrial EECs for naptalam applied to CUCURBITSa estimated using Kenaga valuesb.

Foliage type Maximum residues ( ppm) Mean residues ( ppm)

Short grass 1,045 370 Tall grass 479 157 Broadleaf plants and small insects 588 196 Fruits/ pods/ large insects 65 30 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, and casaba. bApplication rate = 4 lbs a. i./ A, 2 applications, 14 day inverva; half life = 4 days  18 Table 9. Acute, 24 hour average terrestrial EECs for naptalam applied to ORNAMENTAL WOODY CROPS estimated using Kenaga valuesa.

Foliage type Maximum Residues ( ppm) Mean Residues ( ppm)

Short grass 1,920 680 Tall grass 880 288 Broadleaf plants and small insects 1,080 360 Fruits/ pods/ large insects 120 56 aApplication rate = 8 lbs a. i./ A, 1 application; half life = 35 days 4. Non target Plant Exposures Due to the lack of acceptable studies on plant toxicity, exposure modeling was not conducted for non target terrestrial plants.

C. Ecological Effects Characterization In screening level ecological risk assessments, effects characterization describes the types of effects a pesticide can produce in an aquatic or terrestrial organism. This characterization is based on registrantsubmitted studies that describe acute and chronic effects toxicity information for various aquatic and terrestrial animals and plants. Appendix E summarizes the results of the registrant submitted toxicity studies used to characterize effects for this risk assessment. Toxicity testing reported in this section does not represent all species of birds, mammals, or aquatic organisms. Only a few surrogate species for both freshwater fish and birds are used to represent all freshwater fish ( 2000+) and bird ( 680+) species in the United States. For mammals, acute studies are usually limited to Norway rat or the house mouse. Estuarine/ marine testing is usually limited to a crustacean, a mollusk, and a fish. Also, neither reptiles nor amphibians are tested. The risk assessment assumes that avian and reptilian toxicities are similar. The same assumption is used for fish and amphibians.

In general, categories of acute toxicity ranging from " practically nontoxic" to " very highly toxic" have been established for aquatic organisms ( based on LC50 values), terrestrial organisms ( based on LD50 values), avian species ( based on LC50 values), and non target insects ( based on LD50 values for honey bees) ( EPA 2001). These categories are presented in Appendix E.

1. Aquatic Effects The most sensitive acute and chronic toxicity reference values associated with naptalam exposure to freshwater and estuarine/ marine species are summarized in Table 10. A more detailed summary of the aquatic toxicity data available to characterize risks associated naptalam applications is given in Appendix E ( Ecological Effects Data).

a. Aquatic Animals The acute toxicity of naptalam to freshwater fish was evaluated in two species, with 96 hour LC50 values  19 of 76.1 mg/ L for rainbow trout ( Oncorhynchus mykiss) and 118.5 mg/ L for bluegill sunfish ( Lepomis macrochirus). The acute toxicity of naptalam to freshwater invertebrates was evaluated in the daphnid ( Daphnia magna), with a 48 hour LC50 value of 118.5 mg/ L. Based on the acute toxicity classifications established by EPA ( 2001) ( see Appendix E), these results suggest that naptalam is slightly toxic to fish and practically nontoxic to aquatic invertebrates.

No data were submitted on the chronic toxicity of naptalam to freshwater fish or invertebrates. In addition, no data were submitted on the acute or chronic toxicity of naptalam to marine/ estuarine fish or invertebrates.

b. Aquatic Plants No data were submitted on the toxicity of naptalam to non target aquatic plants.

Table 10. Naptalam toxicity reference values ( TRVs) for aquatic organisms. a Exposure scenario Species Exposure duration Toxicity reference value ( mg/ L) Reference Freshwater fish Acute Rainbow trout ( Oncorhynchus mykiss) 96 hour 76.1 MRID 00070193 Core Chronic No test data submitted Freshwater invertebrates Acute Daphnia ( Daphnia magna) 48 hour 118.5 MRID 00082971 Core Chronic No test data submitted Estuarine/ marine fish No test data submitted Estuarine/ marine invertebrates No test data submitted Aquatic plants No test data submitted aA more detailed summary of the aquatic toxicity data available to characterize risks associated with naptalam applications is given in Appendix E.  20 2. Terrestrial Effects a. Terrestrial Animals The most sensitive acute and chronic toxicity references values associated with naptalam exposure to terrestrial organisms are summarized in Table 11. A more detailed summary of these studies, along with additional toxicity data on terrestrial species exposed to naptalam, is given in Appendix E ( Ecological Effects Data).

Table 11. Naptalam toxicity reference values ( TRVs) for terrestrial organisms.

Effects Endpoint Species Exposure Duration Toxicity Reference Value Reference Mammals Acute Rat ( Rattus norvegicus) Single dose SODIUM SALT LD50 = 1,700 mg/ kg bw MRID 29172 Acute Rat Single dose ACID LD50 = > 8,192 mg/ kg bw MRID 76205 Chronic Rat ( Rattus norvegicus) Multigeneration reproduction and fertility effects NOAEL = 30 mg/ kg bwday LOAEL = 150 mg/ kg bw day based on reduced mean pup body weights. MRID 00031684 Core Birds Acute Mallard duck ( Anas platyrhynchos) 96 hours LD50 = > 4,640 mg/ kg bw MRID GS 0183 01 Core Acute Mallard duck ( Anas platyrhynchos) 5 days LC50 = > 10,000 mg/ kg diet MRID 00108853 Core Chronic No test data submitted Non target insects Acute Honeybee ( Apis mellifera) Acute contact LD50 = 113.2 µ g/ bee MRID 00028772 Core Terrestrial plants No test data submitted  21 Mammalian Species Both an acute oral toxicity study in the rat ( Rattus norvegicus) and a multigeneration reproduction study in the rat ( Rattus norvegicus) are available for naptalam. The acute toxicity of naptalam sodium salt ( MRID 29172) as well as naptalam acid ( MRID 76205) were examined. The chronic study was classified as a core ( acceptable) study. Based on the acute toxicity categories established by EPA ( 2001) ( Appendix E), the oral LD50 is 1,700 mg/ kg body weight.

Based on the results in Table 11, naptalam sodium salt is categorized as slightly toxic to small mammals on an acute oral basis ( LD50 = 1,700 mg/ kg bw), naptalam acid is practically non toxic ( LD50 > 8,192), and the potential for chronic reproductive effects appears to be low. In a multigeneration reproduction study in the rat ( Rattus norvegicus) possible systemic toxicity was observed in the offspring in the form of a statistically significant reduction in the mean pup body weights in the high dose group ( 3,000 mg/ kg in the diet or 150 mg/ kg bw). This is equal to the lowest observed adverse effect level ( LOAEL). The noobserved adverse effect level ( NOAEL) for naptalam for reproductive effects was 600 mg/ kg diet or 30 mg/ kg bw ( MRID 00031684). Results of this study along with others are presented in Appendix B, Table B 3. The value of 1,700 mg/ kg bw is used as the toxicity value for assessing acute risks to mammals from exposure to naptalam sodium salt. RQ values were not calculated for naptalam acid because there were no deaths in the study. The systemic NOAEL of 30 mg/ kg bw is used as the toxicity value for assessing chronic risks.

Avian Species For avian species, acute toxicity studies have been conducted in two species, as summarized in Appendix B, Tables B1 to B2. For the mallard ( Anas platyrhynchos), the acute oral LD50 value is > 4,640 mg/ kg bw. The acute dietary LC50 values for the mallard and the bobwhite quail ( Colinus virginianus) are greater than 10,000 mg/ kg diet. These values suggest that naptalam is practically non toxic to birds. Results of reproductive studies of naptalam in birds ( Guideline 71 4) are not available.

Non target Insects Based on the contact LD50 value of 113.2 : g/ bee for the honey bee ( Apis mellifera), naptalam is classified as practically non toxic on an acute contact. Currently, EFED does not assess risk to non target insects. Results of acceptable studies are used for recommending appropriate label precautions. Based on the results of this study in honey bees, the concern for acute toxicity to non target insects is very low.

b. Terrestrial Plants Toxicity data for terrestrial plants was not submitted by the registrant.

IV. RISK CHARACTERIZATION A. Risk Estimation   Integration of Exposure and Effects Data Results of the exposure and toxicity effects data are used to evaluate the likelihood of adverse ecological effects on non target species. For the assessment of naptalam risks, the risk quotient ( RQ) method is used to compare exposure and measured toxicity values ( see Appendix F). Estimated environmental  22 concentrations ( EECs) are divided by acute and chronic toxicity values. The RQs are then compared to the Agency's levels of concern ( LOCs). These LOCs, summarized in Appendix F, are the Agency's interpretive policy and are used to analyze potential risk to non target organisms and the need to consider regulatory action. For non target aquatic animals ( i. e., fish and invertebrates), surface water EECs were obtained from the Tier I GENEEC2 model ( see Table 6). For non target terrestrial animals ( i. e., birds and mammals), the EECs were obtained from ELL FATE ( see Table 8 and Table 9). Toxicity reference values for aquatic and terrestrial organisms exposed to naptalam are summarized in Table 10 and Table 11, respectively.

1. Non target Aquatic Animals and Plants All acute RQ values for freshwater fish and aquatic invertebrates are well below the level of concern for acute high risk ( LOC 0.5), acute restricted risk ( LOC 0.1), or acute endangered risk ( LOC 0.05). Detailed tabular summaries of the RQ calculations for each crop use scenario, receptor, and effects endpoint, are given in Appendix F.

Toxicity data are either inadequate or unavailable to calculate RQs based on the following measurement endpoints ( e. g., acute or chronic toxicity reference values) and receptors:

° chronic ( early life) NOAEC or LOAEC for freshwater fish; ° chronic ( life cycle) NOAEC or LOAEC for freshwater invertebrates; ° acute LC50 for estuarine/ marine fish or invertebrates; ° chronic ( early life) NOAEC or LOAEC for estuarine/ marine fish; ° chronic ( life cycle) NOAEC or LOAEC for estuarine/ marine invertebrates; ° algal and vascular plant EC50 values for growth rate and biomass measurements.

2. Non target Terrestrial Animals RQs for birds and mammals were calculated by comparing toxicity values with EECs representing multiple exposure scenarios for naptalam sodium salt:

° two different crop uses ( cucurbits, with 4 lbs a. i./ A, 2 applications, and 14 day interval; woody ornamentals, with 8 lbs a. i./ A, 1 application); ° foliar dissipation half life of 4 days for curcubits ( 90% UCL from two values reported from dislodgable residue studies); ° default half life of 35 days for ornamental woody plant application ( ELL FATE); ° maximum and mean residue levels; and ° four different foliage types representing potential food/ habitat categories ( short grass; tall grass; broadleaf plants and small insects; and fruits/ pods/ large insects).

Terrestrial mammal acute RQ values were not calculated for naptalam acid because there were no deaths in the study at concentrations as high as 8,192 mg/ kg.

3. Avian Species Avian acute toxicity studies indicate that the LC50 is > 10,000 mg/ kg diet, and no deaths were observed in the study. Therefore, naptalam is classified as practically non toxic and RQ values were not calculated  23 based on the results of the acute toxicity studies.

4. Non target Terrestrial and Semi aquatic Plants Results of the exposure and toxicity effects data are used to evaluate the likelihood of adverse ecological effects on non target species. For the assessment of naptalam risks, the risk quotient ( RQ) method is used to compare exposure and measured toxicity values. Estimated environmental concentrations ( EECs) are divided by acute and chronic toxicity values. The RQs are compared to the Agency's levels of concern ( LOCs). These LOCs are the Agency's interpretive policy and are used to analyze potential risk to nontarget organisms and the need to consider regulatory action. The surface water EECs were obtained from the Tier I GENEEC2 model ( see Table 6) and the EECs for calculating avian and mammalian RQ values were obtained from ELL FATE ( see Table 8 and Table 9).

5. Freshwater Fish and Invertebrates Acute RQ values for freshwater fish and aquatic invertebrates are well below the level of concern for acute high risk ( LOC 0.5), acute restricted risk ( LOC 0.1), or acute endangered risk ( LOC 0.05). These data are summarized in Tables 12 and 13.

Table 12. Acute RQs for evaluating toxic risk of naptalam exposure to freshwater fish. RQs are based on the rainbow trout ( Oncorhynchus mykiss) LC50 = 76.1 ppm. EEC values are generated from GENEEC2.

Crop Application Rate Organism LC/ EC50 ( ppm) EEC Peak ( ppm) Acute RQ ( EEC/ LC50)

Cucurbitsa ( 4 lbs a. i./ A) x 2 ( 14d int) Freshwater fish ( Oncorhynchus mykiss) 76.1 0.452 0.01 Ornamental woody plants ( 8 lbs a. i./ A) x 1 Freshwater fish ( Oncorhynchus mykiss) 76.1 0.471 0.01 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba. 96 hour LC50 for rainbow trout: 76.1 mg/ L.  24 Table 13. Acute RQs for evaluating toxic risk of naptalam exposure to freshwater invertebrates. RQs are based on waterflea ( Daphnia magna) LC50 = 118.5 ppm. EEC values ( ppm) are generated from GENEEC2.

Crop Application Rate Organism LC50 ( ppm) EEC Peak ( ppm) Acute RQ2 Cucurbitsa ( 4 lbs a. i./ A) x 2 ( 14d int) Freshwater invertebrates ( Daphnia magna) 118.5 0.452 0.004 Ornamental woody plants ( 8 lbs a. i./ A) x 1 Freshwater invertebrates ( Daphnia magna) 118.5 0.471 0.004 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba. 48 hour LC50 for Daphnia magna: 118.5 mg/ L.

6. Mammals The RQs for mammalian acute toxicity are provided in Tables 14 and 15. An acute LD50 value of 1,700 mg/ kg for rats was used to calculate acute mammalian RQs for naptalam sodium salt. The RQs based on maximum residues range from 0.001 to 0.42 while the RQs based on mean residues range from 0.0004 to 0.15. The exposure to naptalam sodium salt on short grass, tall grass, and broadleaf plants and small insects appear to pose risks to endangered species and to pose acute restricted use risk for maximum residue conditions for 15 and 35 gram mammals. Exposure to naptalam sodium salt on short grass for 15 and 35 gram mammals poses acute risk to endangered species for mean residue conditions. RQ values were not calculated for naptalam acid because no mortality occurred in the study (> 8,192 mg/ kg bw).  25 Table 14. Acute RQs for mammalian toxicity to naptalam sodium salt applications to CURCUBITSab using a foliar half life value of 4 daysc. RQs estimated using ELL FATE Version 1.4 with an acute LC50 value of 1,700 mg/ kg body weight.

RQs based on maximum residuesd RQs based on mean residues Foliage Type 15 g 35 g 1,000 g 15 g 35 g 1,000 g Short grass 0.58 0.41 0.09 0.21 0.14 0.03 Tall grass 0.27 0.19 0.04 0.09 0.06 0.01 Broadleaf plants and small insects 0.33 0.23 0.05 0.11 0.08 0.02 Fruits/ pods/ large insects 0.04 0.03 0.006 0.02 0.01 0.003 Seeds ( granivores) 0.01 0.006 0.001 0.004 0.003 0.0005 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba. bCurcubit application = 4 lbs a. i./ A, 2 applications, 14 day interval c90% UCL = 90% upper confidence limit on the mean: dThe latest version of ELL FATE, Version 1.4, estimates EEC's and RQs based on maximum and mean residues. The distinction is made by using different Kenaga values for maximum and mean residues. The Kenaga values are lower for the mean residues than the maximum residues. A table of the Kenaga values is included in Appendix E. exceedances are indicated in bold type  26 Table 15. Acute RQs for mammalian toxicity to naptalam sodium salt applications to ORNAMENTAL WOODY PLANTSa using a foliar half life value of 35 daysb. RQs estimated using ELL FATE Version 1.4 with an acute LC50 value of 1,700 mg/ kg body weight.

RQs based on maximum residuesc RQs based on mean residues Foliage Type 15 g 35 g 1,000 g 15 g 35 g 1,000 g Short grass 1.07 0.75 0.17 0.38 0.26 0.06 Tall grass 0.49 0.34 0.08 0.16 0.11 0.03 Broadleaf plants and small insects 0.60 0.42 0.10 0.20 0.14 0.03 Fruits/ pods/ large insects 0.07 0.05 0.01 0.03 0.02 0.00 Seeds ( granivores) 0.01 0.01 0.00 0.01 0.00 0.00 aOrnamental woody plant application = 8 lbs a. i./ A, 1 application;; half life = 35 days bELL FATE default half life cThe latest version of ELL FATE, Version 1.4, estimates EEC's and RQs based on maximum and mean residues. The distinction is made by using different Kenaga values for maximum and mean residues. The Kenaga values are lower for the mean residues than the maximum residues. A table of the Kenaga values is included in Appendix E. exceedances are indicated in bold type The RQs for naptalam mammalian chronic toxicity are provided in Tables 16 and 17. A chronic NOAEL, representing reproduction and fertility effects, of 30 mg/ kg/ day or 600 ppm for rats was used to calculate the chronic mammalian RQs for naptalam. The RQs based on maximum residues for curcubit application range from 0.11  1.74 while the RQs based on mean residues range from 0.05  0.62. The RQs based on maximum residues for ornamental woody plant application range from 0.20  3.20 while the RQs based on mean residues range from 0.09  1.13.

Table 16. Chronic RQs for mammalian toxicity to naptalam applications to CUCURBITSab. RQs estimated using ELL FATE Version 1.4 with an acute LC50 value of 600 ppm.

Foliage Type RQs based on maximum residuesc RQs based on mean residues Short grass 1.74 0.62 Tall grass 0.80 0.26 Broadleaf plants and small insects 0.98 0.33 Fruits/ pods/ large insects 0.11 0.05 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba. bCurcubit application = 4 lbs a. i./ A, 2 applications, 14 day interval cThe latest version of ELL FATE, Version 1.4, estimates EEC's and RQs based on maximum and mean residues. The distinction is made by using different Kenaga values for maximum and mean residues. The Kenaga values are lower for the mean residues than the maximum residues. A table of the Kenaga values is included in Appendix E. exceedances are indicated in bold type  27 Table 17. Chronic RQs for mammalian toxicity to naptalam applications to ORNAMENTAL WOODY PLANTSa. RQs estimated using ELL FATE Version 1.4 with an acute LC50 value of 600ppm.

Foliage Type RQs based on maximum residuesb RQs based on mean residues Short grass 3.20 1.13 Tall grass 1.47 0.48 Broadleaf plants and small insects 1.80 0.60 Fruits/ pods/ large insects 0.20 0.09 aOrnamental woody plant application = 8 lbs a. i./ A, 1 application;; half life = 35 days bThe latest version of ELL FATE, Version 1.4, estimates EEC's and RQs based on maximum and mean residues. The distinction is made by using different Kenaga values for maximum and mean residues. The Kenaga values are lower for the mean residues than the maximum residues. A table of the Kenaga values is included in Appendix E. exceedances are indicated in bold type B. Risk Description   Interpretation of Direct Effects 1. Risks to Aquatic Organisms Naptalam is used as an herbicide on cucumber and watermelon crops, particularly in states such as Florida, Georgia and Texas ( see Section 3( a), Use Characterization); therefore, exposure to this herbicide will primarily occur in the southern regions of the United States where these crops are frequently grown. Addionally, naptalam is applied to ornamental woody plant nursery stock. Following the application of naptalam, spray drift or field runoff may contaminate adjacent ponds, streams, or lakes. Naptalam degrades fairly readily ( half life on the order of a few days) at low pH, but may be more persistent at neutral or alkaline conditions. Naptalam has also been shown to undergo direct photolysis with half lives on the order of several days. However, photolysis in water will be an important degradation pathway only in clear shallow water bodies. In soil, photolysis is only important if the chemical is near the surface. Since naptalam is watered in, photolysis is not expected to play a significant role in its degradation. The environmental persistence of naptalam is expected to be a few weeks to months under most environmental conditions with photolysis, hydrolysis and aerobic biodegradation contributing to its removal from soil and water. Volatilization from soil and water surfaces is not expected to be an important fate process since naptalam exists as an anion in the environment. Naptalam is expected to possess high mobility in soils and leaching to groundwater is a possibility.

Freshwater fish and aquatic invertebrates do not appear to be at acute risk from exposure to naptalam ( risk quotients were orders of magnitude less than the levels of concern). No chronic toxicity data are available for freshwater species and no acute or chronic data are available for estuarine/ marine fish or invertebrates and aquatic plants.

2. Risks to Terrestrial Organisms Naptalam is classified as practically non toxic to birds. RQ values were not calculated based on the results of the acute toxicity studies. The RQs for mammals based on maximum residue EECs calculated with ELL FATE for naptalam application to curcubits range from 0.001 to 0.58 while the RQs based on mean  28 residues range from 0.0005 to 0.21. The exposure to naptalam sodium salt on short grass, tall grass, broadleaf plants, and small insects resulting from curcubit application exceeds endangered species and acute restricted use levels of concern for maximum residue conditions for 15 and 35 gram mammals, and the LOC for acute risk is exceeded for 15g mammals that feed on short grass based on maximum residues. Exposure to naptalam sodium salt on short grass, broadleaf plants, and small insects for 15 and 35 gram mammals also exceeds the endangered species levels of concern for mean residue conditions.

The exposure to naptalam sodium salt on short grass, tall grass, broadleaf plants, and small insects resulting from ornamental woody plant application exceeds endangered species and acute restricted use levels of concern for maximum residue conditions for 15 and 35 gram mammals, and for 1000 gram mammals on short grass. Additionally, the acute LOC is exceeded for 15 and 35 gram mammals based on maximum residues on short grass, broadleaf plants, and small insects. Exposure to naptalam on short grass, broadleaf plants, and small insects for 15 and 35 gram mammals from ornamental woody plant application also exceeds the endangered species levels of concern for mean residue conditions.

Chronic RQ values from naptalam curcubit application based on maximum residues range from 0.11  1.74, while the RQs based on mean residues range from 0.05  0.62. Chronic mammalian RQs from naptalam ornamental woody plant application based on maximum residues range from 0.2  3.2 and 0.09  1.13 for maximum and mean residues, respectively.

Chronic LOCs are exceeded for naptalam application to curcubits for mammals that feed on short grass based on maximum residue values. Additionally mammalian chronic LOCs are exceeded for naptalam application to ornamental woody plants at maximum residue conditions on short grass, tall grass, broadleaf plants, and small insects. Mean residue values generate an LOC exceedance for mammals that feed on short grass.

This risk may be overestimated because naptalam acid is practically non toxic to mammalian species. Due to its environmental fate properties, it is assumed the most of the naptalam sodium salt will dissociate at environmental pH levels to form the non toxic naptalam acid and sodium cations. It is therefore possible that the naptalam sodium salt acute endpoint ( 1,700 mg/ kg bw) overestimates risk, due to the fact that very little of this chemical will persist in the environment long enough to lead to mammalian exposure.

3. Review of Incident Data There have been no incidents related to naptalam reported to the Environmental Incident Information System ( EIIS) database ( reported to the Agency from 1991 to 2003).

4. Endocrine Effects Due to the lack of available data, it cannot be determined whether naptalam exhibits endocrine toxicity in aquatic organisms. Studies on the effects of naptalam on avian reproduction were not submitted to the Agency; thus, no conclusion can be made regarding the potential for naptalam to cause endocrine disruption in avian species. In a multigeneration reproduction study in the rat ( Rattus norvegicus) possible systemic toxicity was observed in the offspring in the form of statistically significant reduction in the mean pup body weights in the high dose group ( 3,000 mg/ kg in the diet or 150 mg/ kg bw) ( MRID 00031684).  29 Under the Federal Food, Drug and Cosmetic Act ( FFDCA), as amended by the Food Quality Protection Act ( FQPA), EPA is required 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 effect produced by a naturally occurring estrogen, or other such endocrine effects as the Administrator may designate." Following the recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee ( EDSTAC), EPA determined that 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 recommendation that 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 Screening Program ( EDSP). When the appropriate screening and or testing protocols being considered under the Agency's Endocrine Disruptor Screening Program have been developed, naptalam may be subjected to additional screening and or testing to better characterize effects related to endocrine disruption.

5. Threatened and Endangered Species Concerns a. Taxonomic Groups Potentially at Risk The registrant must provide information on the proximity of Federally listed endangered species to the naptalam use sites. This requirement may be satisfied in one of three ways: 1) having membership in the FIFRA Endangered Species Task Force ( Pesticide Registration Notice 2000 2); 2) citing FIFRA Endangered Species Task Force data; or 3) independently producing these data, provided the information is of sufficient quality to meet FIFRA requirements. The information will be used by the OPP Endangered Species Protection Program to develop recommendations to avoid adverse effects to listed species.

Curcubit Applications The Agency's acute levels of concern ( LOC) for endangered/ threatened species are exceeded for 15g and 35g mammals that feed on short grass, tall grass, broadleaf plants, and small insects in or near curcubit fields based on maxiumum naptalam residues. Mean naptalam residue values lead to endangered species acute LOC exceedances for 15g and 35g mammals that feed on short grass, and maximum residue levels lead to endangered species LOC exceedances for 15g and 35g mammals that feed on short grass, long grass, broadleaf plants, and small insects.

The chronic endangered species LOC is exceeded for mammals that feed on short grass in or near curcubit fields based on maximum naptalam residue values.

Ornamental Woody Plant Applications The Agency's acute levels of concern ( LOC) for endangered/ threatened species are exceeded for 15g and 35g mammals that feed on short grass, tall grass, broadleaf plants, and small insects where ornamental woody plants are grown based on maxiumum and mean naptalam residues. Large ( 1000g) mammal LOC exceedances occur for animals that feed on short grass, broadleaf plants, and small insects based on maximum naptalam residues.

The chronic endangered species LOC is exceeded for endangered/ threatened mammals that feed on short grass, tall grass, broadleaf plants, and small insects where ornamental woody plants are grown based on  30 maximum naptalam residue values. The chronic LOC is also exceeded for mammals that feed on short grass based on mean naptalam residue values.

Listed species Fifty six endangered or threatened mammal species inhabit states where naptalam is used. However, many of these listed species are not at risk through naptalam exposure based on size, food items, and habitat. The entire list of listed endangered/ threatened mammalian species can be found in Appendix G. Those species whose size and feeding habits lead to possible acute naptalam exposure include the following ( 25 species):

° Ferret, Black Footed ° Kangaroo Rat ( Fresno, Giant, Morro Bay, San Bernardino, Stephens', and Tipton) ° Mouse ( Alabama Beach, Choctawhatchee Beach, Pacific Pocket, Perdido Key Beach, Preble's Meadow Jumping, Salt Marsh Harvest, and Southeastern Beach) ° Prarie Dog, Utah ° Rabbit ( Pygmy and Riparian Brush) ° Shrew, Buena Vista ° Squirrel ( Carolina Northern Flying, Delmarvia Peninsula Fox, Mount Graham Red, and Virginia Northern Flying) ° Vole ( Amargosa and Florida Salt Marsh) ° Woodrat, Riparian b. Probit Slope Analysis The probit slope response relationship is evaluated to calculate the chance of an individual event corresponding to the listed species acute LOCs. If information is unavailable to estimate a slope for a particular study, a default slope assumption of 4.5 is used as per original Agency assumptions of typical slope cited in Urban and Cook ( 1986). Analysis of raw data from the rat naptalam acute toxicity study ( MRID 29172) estimate a slope of 7.94 ( 95% C. I. 3.9  11.9). Based on this slope, the corresponding estimate chance of individual mortality of mammals following naptalam exposure is 1 in 1 x 1015. To explore possible bounds to such estimates, the upper and lower values for the mean slope estimate ( 3.9  11.9) can be used to calculate upper and lower estimates of the effects probability associated with the listed species LOC. These values are 1 in 20,800 and 1 in 1x1016. RQ exceedances only occur for 15g and 35g mammals, with RQ values ranging from 1.07 to the LOC ( 0.1). The estimated individual mortality associated with the calculated RQ values ( 0.1 to 1.07) range from 1 in 1 x 1015 to 1 in 1 ( 100%), respectively.  31 c. Critical Habitat In the evaluation of pesticide effects on designated critical habitat, consideration is given to the physical and biological features ( constituent elements) of a critical habitat identified by the U. S Fish and Wildlife and National Marine Fisheries Services as essential to the conservation of a listed species and which may require special management considerations or protection. The evaluation of impacts for a screening level pesticide risk assessment focuses on the biological features that are constituent elements and is accomplished using the screening level taxonomic analysis ( risk quotients, RQs) and listed species levels of concern ( LOCs) that are used to evaluate direct and indirect effects to listed organisms.

The screening level risk assessment has identified potential concerns for indirect effects on listed species for those organisms dependant upon small ( 15g) and medium ( 35g) sized mammals. In light of the potential for indirect effects, the next step for EPA and the Service( s) is to identify 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 any listed species. If so, EPA would examine whether the pesticide's potential impacts on non endangered species would affect the listed species indirectly or directly affect a constituent element of the critical habitat. Alternatively, the agencies could determine which listed species depend on biological resources, or have constiuent elements that fall into, the taxa that may be directly or indirectly impacted by the pesticide. 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 reviewed by EPA does not permit use of either analytical approach to make a definitive identification of species that are potentially impacted indirectly or critical habitats that is potentially impacted directly by the use of the pesticide. EPA and the Service( s) are working together to conduct the necessary analysis.

This screening level risk assessment for critical habitat provides a listing of potential biological features that, if they are constituent elements of one or more critical habitats, would be of potential concern. These correspond to the taxa identified above as being of potential concern for indirect effects and include small and medium sized mammals. This list should serve as an initial step in problem formulation for further assessment of critical habitat impacts outlined above, should additional work be necessary" d. Indirect Effect Analysis The Agency acknowledges that pesticides have the potential to exert indirect effects upon the listed organisms by, for example, perturbing forage or prey availability, altering the extent of nesting habitat, creating gaps in the food chain, etc.

In conducting a screen for indirect effects, direct effect LOCs for each taxonomic group are used to make inferences concerning the potential for indirect effects upon listed species that rely upon non endangered organisms in these taxonomic groups as resources critical to their life cycle.

Because screening level acute RQs for mammals exceed the endangered species acute LOCs, the Agency uses the dose response relationship from the toxicity study used for calculating the RQ to estimate the probability of acute effects associated with an exposure equivalent to the EEC. This information serves as a guide to establish the need for and extent of additional analysis that may be performed using Servicesprovided " species profiles" as well as evaluations of the geographical and temporal nature of the exposure to ascertain if a " not likely to adversely affect" determination can be made. The degree to which additional analyses are performed is commensurate with the predicted probability of adverse effects from the  32 comparison of the dose response information with the EECs. The greater the probability that exposures will produce effects on a taxa, the greater the concern for potential indirect effects for listed species dependent upon that taxa, and therefore, the more intensive the analysis on the potential listed species of concern, their locations relative to the use site, and information regarding the use scenario ( e. g., timing, frequency, and geographical extent of pesticide application).

Screening level chronic RQs for mammals that feed on short grass exceed the LOC; therefore, there may be a potential concern for indirect effects. The Agency considers this to be indicative of a potential for adverse effects to those listed species that rely either on a specific plant species ( plant species obligate) or multiple plant species ( plant dependent) for some important aspect of their life cycle. The Agency may determine if listed organisms for which plants are a critical component of their resource needs are within the pesticide use area. This is accomplished through a comparison of Service provided " species profiles" and listed species location data. If no listed organisms that are either plant species obligates or plant dependent reside within the pesticide use area, a no effect determination on listed species is made. If plant species obligate or dependent organism may reside within the pesticide use area, the Agency may consider temporal and geographical nature of exposure, and the scope of the effects data, to determine if any potential effects can be determined to not likely adversely affect a plant species obligate or dependent listed organism.

Indirect effects to terrestrial animals may result from reduced food items to animals, behavior modifications from reduced or a modified habitat, and from alterations of habitats. Alterations of habitats can affect the reproductive capacity of some terrestrial animals.

C. Description of Assumptions, Uncertainties, Strengths, and Limitations Data Gaps There are several environmental fate data gaps that lead to uncertainties with regards to exposure and predicted environmental concentrations. Information on the hydrolysis of naptalam under neutral and alkaline conditions is lacking. Also missing are batch equilibrium studies on naptalam and its major degradates. Therefore, assumptions were made, based upon information in the open literature, about the mobility of naptalam in soil. There are also no studies available on the potential for naptalam to accumulate in fish. Based on the very high octanol water partition coefficient, it is assumed that naptalam will bioaccumulate. Accumulation in fish studies, which provide bioconcentration factors, would reduce the uncertainties in this area. Finally, scientifically valid terrestrial field dissipation studies have not been submitted. As a result, we have no information on the fate and transport of naptalam and its degradates under actual field conditions. While the laboratory studies are designed to address one dissipation process at a time, terrestrial field dissipation studies address pesticide loss as a combined result of chemical and biological processes ( e. g., hydrolysis, photolysis, microbial transformation) and physical migration ( e. g., volatilization, leaching, plant uptake). Pesticide dissipation may proceed at different rates under field conditions and may result in formation of degradates at levels different from those observed in laboratory studies. Data from these studies can reduce potential overestimation of exposure and risk and can confirm assumptions of low levels of toxic degradates.

Ecotoxicity data for terrestrial and aquatic animals are limited by the number of species tested. Species variability in toxicity to chemicals can, at times, be quite high. Additionally, using only one species to characterize risk for all animals in a species category may result in the underestimation of risks for a particularly sensitive animal while overestimating the risks of others. In addition, use of laboratory rats as surrogates for wild animals has inherent uncertainties because laboratory animals are generally bred to  33 minimize genetic variability and to be sensitive to chemical exposures ( i. e., likely to exhibit responses at lower doses). In these cases, toxicity may be overstated. Although it appears that naptalam is relatively non toxic to freshwater aquatic organisms, chronic risk from naptalam exposure and risk to estuarine/ marine animals cannot be assessed due to a lack of data.

The screening level assessment strongly suggests that risks to freshwater aquatic organisms are well below levels of concern for acute or chronic effects. Even though naptalam may not degrade rapidly in water ( hydrolysis is pH dependent), the toxicity data suggest naptalam may be slightly toxic to fish and is nontoxic to aquatic invertebrates.

The screening level assessment for mammals suggests that there are several scenarios in which both acute and chronic LOCs are exceeded. The greatest source of uncertainty in the assessment of acute mammalian risks stems from the single reported acute oral LD50 value of the naptalam sodium salt ( 1,700 mg/ kg body weight), and the study needs to be more closely evaluated to confirm that it can be classified as acceptable for use in quantitative risk assessment. The naptalam acid is practically non toxic to mammalian species, and due to its environmental fate properties, it is assumed the most of the naptalam sodium salt will dissociate at normal environmental pH levels to form the non toxic naptalam acid and sodium cations. It is therefore possible that the naptalam sodium salt acute endpoint ( 1,700 mg/ kg bw) overestimates risk, due to the fact that very little of this chemical will persist in the environment long enough to lead to mammalian exposure. Other sources of uncertainty related to the protective assumptions inherent in the use of ELLFATE as screening level model ( e. g., maximum residues, first order kinetics, etc.). This model is intended to yield high end estimates of exposure, and the marginal exceedance of the LOCs ( i. e., < 2X) suggest that a more refined assessment of exposure may yield a more refined estimate of the acute and chronic risks.  34 V. Literature Cited Open Literature and Governmental Reports Applegate VC, Howell JH, Hall AE Jr, et al. 1957. Toxicity of 4,346 chemicals to larval lampreys and fishes. U. S. Fish Wildlife Service Special Scientific Report  Fisheries 207: 1  157.

ELL FATE. 2004. Terrestrial Exposure and Risk Model Version 1.4. April 7, 2004. Environmental Fate and Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C.

EPA ( U. S. Environmental Protection Agency). 2000. Quantitative Usage Analysis for Naptalam, Case Number: 0183. PC Code: 30703. Analyst: Jihad Alsadek. September 19, 2000.

EPA ( U. S. Environmental Protection Agency). 2001. Ecological Risk Assessor Orientation Package, Draft. Montague M., Ecological Fate and Environmental Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C. August.

EPA ( U. S. Environmental Protection Agency). 2002a. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides. Version II. Support Document # 9. Ecological Fate and Environmental Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C.

EPA ( U. S. Environmental Protection Agency). 2002b. ECOTOX User Guide: ECOTOXicology Database System. Version 3.0. Available at: http:// www. epa. gov/ ecotox/. Accessed: May 2004.

EPA ( U. S. Environmental Protection Agency). 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U. S. Environmental Protection Agency: Endangered and Threatened Species Effects Determinations. Office of Prevention, Pesticide, and Toxic Substances. January 23.

FIRST. 2001. FQPA Index Reservoir Screening Tool, Version 1.0. August 1, 2001. Environmental Fate and Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C.

GENEEC. 2001. Generic Estimated Environmental Concentrations, Version 2.0. August 1, 2001. Environmental Fate and Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C.

Granados A., Nasseta M., DeRossi R. H. 1995. Kinetic study of the hydrolysis of 1 naphthylphthalamic acid ( naptalam). J. Agric. Food Chem. 43: 2493  2496.

Huang CH., Stone AT. 1999. Hydrolysis of naptalam and structurally related amide: Inhibition by dissolved metal ions and metal ( hydr) oxide surfaces. J. Agric. Food Chem. 47: 4425  4434.

Loeb, H. A., and W. H. Kelly. 1963. Acute oral toxicity of 1,490 chemicals force fed to carp. U. S. Fish Wildlife Service Special Scientific Report  Fisheries 471: 1  124.  35 Lysak, A., and J. Marcinek. 1972. Multiple toxic effect of simultaneous action of some chemical substances on fish. Roczniki Nauk Rolniczych 94: 53  63.

NCFAP. 2004. National Center for Food and Agricultural Policy. National Pesticide Use Database. Naptalam  1997 National Summary of Pesticide Use in Crop Production by Active Ingredient and Crop. Information taken on September 8, 2004 from the website: http:// www. ncfap. org/ database/ default. htm.

SCI GROW. 2001. Screening Ground Water Model, Version 2.2. November 1, 2001. Environmental Fate and Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C.

Tomlin, C. D. S. ( Ed.). 1997. The Pesticide Manual  World Compendium, 11th ed., British Crop Protection Council, Surrey, England.

Tonogai Y, Ogawa S, Ito Y, Iwaida M. 1982. Actual survey on TLm ( Median Tolerance Limit) values of environmental pollutants, especially on amines, nitriles, aromatic nitrogen compounds and artificial dyes. J. Toxicol. Sci. 7: 193  203.

USGS ( U. S. Geological Survey). 2004. National Water Quality Assessment Program ( NAWQA) Pesticide National Synthesis Project. National assessment of pesticides in the streams, rivers, and ground water of the United States. Available at http:// ca. water. usgs. gov/ pnsp/. Accessed: September 2004. Weber 1994. Properties and behavior of pesticides in soil. In: Mechanisms of Pesticide Movement into Ground Water. Honeycutt, RC & Schadebacker, DJ, eds. Ann Arbor, MI: Lewis Publ., CRC press, inc. pp. 15  41.

Weed Science Society of America. 1994. Naptalam 2[( 1 napthalenylamino) carbonyl)] benzoic acid. Herbicide Handbook, 7th Edition. Editor, W H Ahrens.  A 1 APPENDIX A. Environmental Fate Studies Hydrolysis 161 1 ( MRID 43647701)

Non radiolabeled naptalam and naphthalene ring labeled [ 14C] naptalam, at a nominal concentration of 51.9 ppm, degraded with a reviewer calculated half life of 2.9 days in sterilized pH 5 aqueous buffer solution incubated in darkness at 25 ° C for up to 21 days. The registrant calculated half life was approximately 1 day. The parent compound initially present ( mean of duplicate) at 96.6% of the applied radioactivity, decreased to 48.5% by 1 day, 25% by 4 days, and 5.0% by 8 days, and was 1.1% ( one replicate) at 21 days post treatment. Three main degradates were observed. The major degradate 1 naphthylamine was a maximum ( mean of duplicate) of 86.9% of the applied radioactivity at 21 days post treatment. The major degradate N( 1 naphthyl) phthalimide was a maximum of 13.5% of the applied radioactivity at 2 days post treatment and was 3.4% at 21 days. The major degradate ( non radiolabeled) phthalic acid was a maximum ( mean of duplicate) of 20.4 ppm at 21 days post treatment. This study is considered supplemental since no data were provided at pH 7 and 9.

Huang and Stone ( 1999) demonstrated that dissolved metal ions ( Cu2+ and Zn2+) inhibit the rate of hydrolysis for naptalam when compared to metal free solutions. The hydrolysis half life of naptalam in pH 5 solution containing 1 mM ( millimolar) CuCl2 was over 200 hours, while the half life in metal free solution was about 100 hours. The pH dependence of naptalam hydrolysis was also investigated and it was concluded that hydrolysis is an acid catalyzed reaction, which occurs much more rapidly under acidic conditions as compared to neutral or alkaline pH. Over the course of a 14 day incubation period, the hydrolysis of naptalam was considered negligible at pH 7.5, but increased dramatically as the pH was lowered to 4. At pH 4 approximately 90% of the initially applied amount of naptalam was converted to its main degradate 1 naphthylamine in about a day in metal free solutions. In solutions containing either 1 mM ZnCl2 or CuCl2, only about 80% conversion was observed in the same time frame. It was also noted that as the levels of ZnCl2 and CuCl2 were increased from 1 to 4 mM, the amount of hydrolysis to 1 naphthylamine decreased.

The mechanism and rate of hydrolysis of naptalam was studied at pH range 0.9 to 5. At pH 5 the hydrolysis half life was calculated as 29 hours, while at lowest pH ( pH 0.9) the half life was about 46 minutes ( Granados et al., 1995).

Aqueous Photolysis 161 2 ( MRID 41385401)

Naptalam photodegraded with half lives in the range of 6.2  6.9 days in sterile aqueous pH 7 buffered 0.001 M and 0.01 M phosphate solutions and 10.3 days in 0.1 M phosphate solutions that were continuously irradiated with a xenon arc lamp ( 890 W/ m2). Naptalam did not degrade in dark control samples. At 15 days post treatment naptalam comprised 18.6  21.3% of the applied radioactivity. The major degradation product observed was 1 naphthylamine comprising 47.5  49.8% of the applied radioactivity 15 days post treatment. N( 1 naphthyl) phthalimide was also observed, comprising 7.3  7.5% of the applied radioactivity post treatment. The study was considered supplemental since not all the radioactivity was accounted for in the test samples.  A 2 Soil Photolysis 161 3 ( MRID 41385402)

Naptalam degraded with an observed half life of 15.9 days in a sandy loam soil ( 63% sand, 31% silt, 6% clay, 4.7% organic matter, pH 6.8) that was continuously irradiated with a xenon arc lamp ( 700  750 W/ m2). In a dark control the degradation half life was 22.4 days; therefore, it was concluded that biodegradation had occurred even though the soil samples had been autoclaved. The degradates 1 naphthylamine and N( 1 naphthyl) phthalimide were detected in both the irradiated samples and dark control at levels less than 7% of the initially applied amount. The study was considered supplemental since not all the radioactivity was accounted for in the test samples.

Aerobic Soil Metabolism 162 1 ( MRID 41427201)

Naptalam degraded with a half life of 36.7 days in a sandy loam soil ( 62% sand, 28% silt, 10% clay, 5% organic matter, pH 6.5) that was incubated in the dark at moisture content of 75% field capacity. 14C labeled naptalam degraded from 93% ( 5.98 ppm) of the applied radioactivity at day 0 to 39.4% ( 2.53 ppm) at 41 days post application, to 3.6% ( 0.23 ppm) at 135 days post application. Two non volatile degradates were identified: N( 1 naphthyl) phthalimide which was a maximum of 6.1% of the applied radioactivity at day 41 and 1 naphthylamine, which reached a maximum of 2.2% of the applied radioactivity slightly after application. At 135 days post application 14CO2 accounted for 39.5% of the initially applied radioactivity.

Anaerobic Soil Metabolism 162 2 ( MRID 41427202)

Naptalam degraded with a half life of 246 days in a sandy loam soil ( 62% sand, 28% silt, 10% clay, 5% organic matter, pH 6.5) that was incubated anaerobically in the dark following 30 days of aerobic incubation. Naptalam declined from 5.98 ppm ( immediately following application) to 4.14 ppm 30 days post application ( just prior to establishing anaerobic conditions). The concentration declined over the following 60 days under anaerobic conditions to 3.48 ppm. Two non volatile degradates were identified, N 1 naphthylphtalimide and 1 naphthylamine, which reached maximum levels of 0.42 and 0.12 ppm, respectively, after 31 days of anaerobic incubation.

Adsorption/ Desorption 163 1 No data were submitted regarding the adsorption/ desorption of naptalam from soil surfaces. Although no experimental details were provided a soil Koc value of 20 has been reported ( Weber, 1994), which indicates naptalam will have very high mobility in soils. It is noted that naptalam exists as an anion in water and moist soil surfaces and anionic species tend to have very high mobility in soils.

Terrestrial Field Dissipation 164 1 ( 41385403; 40488901)

MRID 40488901 Naptalam ( Alanap L, formulation not further identified) was sprayed at 4 lb ai/ A as a tank mix with bensulide ( Prefar, formulation and source unidentified, 6 lb ai/ A) to a field plot ( 75 x 200 feet) of silty clay loam soil ( 8.8 % sand, 55.6% silt, 35.6 % clay, 1.43% organic matter, pH 6.2) planted to honeydew ( type and growth stage unspecified) and located in Lafayette, Indiana; the application occurred on May 20, 1985. Immediately following treatment, the soil was cultivated to a 2 inch depth to incorporate the  A 3 herbicides plus a soil conditioner ( undescribed). An untreated plot ( size and location unspecified) was maintained as a control. Ten to fifteen soil cores ( diameter unspecified; 0 to 6 and 6 to 12 inch depths) were taken from the treated plot prior to treatment and at 0, 3, 7, 14, 30, and 60 days post treatment. Soil samples were stored ( storage conditions were not adequately described) approximately 520 days prior to analysis. Total naptalam residues dissipated in the 0  6 inch soil core with half lives of 3  7 days. This study was deemed unacceptable since sampling intervals were inadequate to accurately establish the halflife and the analytical method did not distinguish between naptalam and its degradation products.

MRID 413854031 Naptalam ( Alanap L, 2 lb/ gallon SC/ L, Uniroyal Chemical) was surface applied twice at a rate of 4 lb ai/ A/ application to two field plots ( 50 x 50 feet) located near Kerman, California. The first plot was sandy loam soil ( 69% sand, 21% silt, 10% clay, 0.66% organic matter, pH 6.1, CEC 4.1 meq/ 100 g) and was treated on June 28, 1988. The second field plot was loamy sand soil ( 83.6% sand, 10.0% silt, 6.4% clay, 0.3% organic matter, pH 6.3, CEC 3.5 meq/ 100 g) and was treated on July 6, 1988. The plots were harrowed prior to treatment; immediately following the applications, the plots were cultivated ( weasel) to a 2 inch depth and hand planted watermelon. The second application was made to each plot post emergence ( 26  27 days post planting); the first plot was treated on July 25, 1988, and the second plot was treated on August 1, 1988. Following the second application, the plots were cultivated to a 2 inch depth. Total naptalam residues dissipated in the 0  6 inch soil core with a half life of 37.4 days in the California sandy loam and dissipated in the 0  6 inch soil core of the California loamy sand with a half life of 10.6 days. These studies were deemed unacceptable for several reasons including sampling intervals that were inadequate to accurately establish the half life and the analytical method did not distinguish between naptalam and its degradation products.

Literature Cited MRID 43647701 Kabler, A. K. 1995. N 1 Naphthylphthalamic acid ( Naptalam): determination of the rate of hydrolysis at pH 5. Performed by Toxikon Environmental Sciences. Sponsored by Uniroyal Chemical Co. Project ID: J9501005.

MRID 41427201 Cohen, S.; Levine, A. ( 1990) Aerobic Soil Metabolism of ALANAP: Lab Project Number: 8966: 008/ 005/ 004/ 89. Unpublished study prepared by University of Pittsburgh Applied Research Center. 144 p.

MRID 41427202 Cohen, S.; Levine, A. ( 1990) Anaerobic Soil Metabolism of ALANAP: Lab Project Number: 8967: 008/ 005/ 005/ 89. Unpublished study prepared by University of Pittsburgh Applied Research Center. 11pp.

MRID 41385401 Gaydosh, K. ( 1989) Aqueous Photolysis of Naptalam Sodium Salt Lab Project Number: 8992. Unpublished study prepared by Uniroyal Chemical Co., Inc. 35 p.

MRID 00145416 Gerecke, D.; Lacadie, J.; Dzialo, D.; et al. ( 1978) Aerobic Soil Study of Carbon 14 Alanap in Sandy Loam Soil: Project No. 7761. Unpublished study prepared by Uniroyal Chemical. 13p.

       Granados A., Nasseta M., DeRossi R. H. 1995. Kinetic study of the hydrolysis of  A 4 1 naphthylphthalamic acid ( naptalam). J. Agric. Food Chem. 43: 2493  2496.

       Huang CH., Stone AT. 1999. Hydrolysis of naptalam and structurally related amide: Inhibition by dissolved metal ions and metal ( hydr) oxide surfaces. J. Agric. Food Chem. 47: 4425  4434.

MRID 41385402 Korpalski, S. ( 1989) Soil Photolysis of Carbon 14 Naptalam Sodium Salt Lab Project 89109. Unpublished study prepared by Uniroyal Chemical Co., Inc. 42 p.

MRID 40488901 McManus, J. ( 1987) Soil Field Dissipation of Alanap in Lafayette, Indiana: Laboratory Project ID 8627. Unpublished study performed by Uniroyal Chemical Company, Inc. 44 p.

       Weber 1994. Properties and behavior of pesticides in soil. In: Mechanisms of Pesticide Movement into Ground Water. Honeycutt, RC & Schadebacker, DJ, eds. Ann Arbor, MI: Lewis Publ., CRC press, inc. pp. 15  41.

MRID 41385403 White, C.; Beevers, M.; Noon, P. ( 1989) Terrestrial Field Dissipation of Alanap on Two California Melon Fields: Lab Project Number: 8782. Unpublished study prepared by Uniroyal Chemical Co., in cooperation with California Agricultural Research, Inc., and North Coast Laboratories, Inc. 188 p.  B 1 APPENDIX B. Aquatic Exposure Model ( FIRST, SCI GROW, and GENEEC2)   Inputs, Results, Output 1. Surface Water Modeling a. Background Information on FIRST Version 1.0 FIRST Version 1.0 ( 2001) was used to estimate concentrations that may occur in vulnerable surface waters. FIRST is a screening model designed to estimate the pesticide concentrations found in water for use in human health drinking water assessments. It provides high end estimates of the concentrations that might be found in a small drinking water reservoir due to the use of pesticide. Like GENEEC2, the model previously used for Tier I screening level assessments, FIRST is a single event model ( one run off event). It can also account for spray drift from multiple applications. FIRST takes into consideration the so called Index Drinking Water Reservoir ( see below) by representing a larger field and pond than the standard GENEEC2 scenario. The FIRST scenario includes a 427 acre field immediately adjacent to a 13 acre reservoir, 9 feet deep, with continuous flow ( two turnovers per year). The pond receives a spray drift event from each application plus one runoff event. The runoff event moves a maximum of 8% of the applied pesticide into the pond. This amount can be reduced due to degradation on the field and the effect of binding to soil. Spray drift is equal to 6.4% of the applied concentration from the ground spray application and 16% for aerial applications.

FIRST also makes adjustments for the percent crop area ( PCA). While FIRST assumes that the entire watershed would not be treated, the use of a PCA is still a screen because it represents the highest percentage of crop cover of any large watershed in the United States, and it assumes that the entire crop is being treated. Various other protective assumptions of FIRST include the use of a small drinking water reservoir surrounded by a runoff prone watershed, the use of the maximum application rate, no buffer zone, and a single large rainfall.

I. Index Reservoir The index reservoir represents potential drinking water exposure from a specific area ( Illinois) with known cropping patterns, weather, soils, and other factors. One source of uncertainty is the extent to which this index reservoir is representative of areas with different climates, crops, pesticides used, sources of water ( e. g., rivers instead of reservoirs, etc.), and hydrogeology. In general, because the index reservoir represents a fairly vulnerable watershed, the concentration estimated with the index reservoir will likely be higher than the actual concentration for most drinking water sources. However, the index reservoir is not a worst case scenario. Communities that derive their drinking water from smaller bodies of water with minimal outflow, or with more runoff prone soils, would likely receive higher drinking water exposures. Areas with a more humid climate that use a similar reservoir and cropping patterns may also receive higher exposures in their drinking water than predicted using this scenario.

A single steady flow has been used to represent the flow through the reservoir. Discharge from the reservoir also removes chemicals so this assumption will underestimate removal from the reservoir during wet periods and overestimate removal during dry periods. This assumption can both underestimate or overestimate the concentration in the pond depending upon the annual precipitation pattern at the site.  B 2 The index reservoir scenario uses the characteristics of a single soil to represent the soil in the basin. In fact, soils can vary substantially across even small areas, and this variation is not reflected in these simulations.

The index reservoir scenario does not consider tile drainage. Areas that are prone to substantial runoff are often tile drained. Portions of the cotton growing regions of Mississippi are known to have tile drains. Tile drainage contributes additional water and in some cases, additional pesticide loading to the reservoir. This may cause either an increase or decrease in the pesticide concentration in the reservoir. Tile drainage also causes the surface soil to dry out faster. This will reduce runoff of the pesticide into the reservoir. The watershed used as the model for the index reservoir ( Shipman City Lake) does not have tile drainage in the cropped areas.

ii. Percent Crop Area The PCA is a watershed based modification to the results of the index reservoir. Implicit in its application is the assumption that field scale models currently in use reflect basin scale processes consistently for all pesticides and uses. In other words, we assume that the large field simulated by FIRST are reasonable approximations of pesticide fate and transport within a watershed that contains a drinking water reservoir. If the models fail to capture pertinent basin scale fate and transport processes consistently for all pesticides and all uses, the application of a factor that reduces the estimated concentrations predicted by modeling could, in some instances, result in inadvertently passing a chemical through the screen that may actually pose a risk. A preliminary survey of water assessments which compared screening model estimates to readily available monitoring data suggest uneven model results. In some instances, the screening model estimates are more than an order of magnitude greater than the highest concentrations reported in available monitoring data; in other instances, the model estimates are less than monitoring concentrations. Because of these concerns, the Scientific Advisory Panel recommended using the PCA only for ` major' crops in the Midwest. For other crops, development of PCAs will depend on the availability of relevant monitoring data that could be used to evaluate the result of the PCA adjustment.

The spatial data used for the PCA came from readily available sources and have a number of inherent limitations related to the size of the watershed, the distance between the treated fields and the water body is not addressed, and data from the 1992 Census of Agriculture was used. The PCA adjustment is only applicable to pesticides applied to agricultural crops. Contributions to surface waters from nonagricultural uses such as urban environments are not well modeled. Currently, non agricultural uses are not included in the screening model assessments for drinking water.

b. Model Inputs and Results FIRST was run for row crops using the proposed label application rate ( 4lb a. i./ A). An aerial application was chosen in accordance with the product label and the default setting for the depth of incorporation of 0 inches was used. According to the Agency's guidelines for selecting inputs for Tier 1 models ( EPA, 2002a), the default PCA of 0.87 was used. Table B 1 shows the input parameters used in the FIRST and GENEEC2 models ( see Aquatic Exposure Assessment for GENEEC2 results).

The peak, 24 hour expected EEC generated from FIRST is 685.5 ppb and the annual average is 250.7 ppb ( see Table B 2). The 24 hour peak, 21 day and 60 day EECs estimated from GENEEC2 are 452.4, 442.2, and 423.1 ppb, respectively.  B 3 Table B 1. Input parameters for naptalam used in GENEEC2 and FIRST.

Parameter Value Source Crop Cucurbitsa Ornamental woody plants Master label Water solubility ( mg/ L at 25 ° C) 249,000 Weed Science Society of America, 1994 Hydrolysis half life ( days) stable ( at pH 7) MRID 41385401 Aerobic soil metabolism half life ( days) 110 36.7 days x 3 ( MRID 41427201) EPA, 2002a Aerobic aquatic metabolism half life ( days) 220 No study; value calculated as 2 x aerobic soil t ½ ( EPA, 2002a)

Aqueous photolysis half life ( days) 6.2 MRID 41385401 Adsorption coefficient ( Koc) c 20 Weber, 1994 Pesticide is wetted in Yes Master label Application method ( for maximum application rate) Aerial Master label Application rate ( lb a. i./ A) Cucurbitsa: 4 Ornamental woody plants: 8 Master label Maximum number of applications per year Cucurbitsa: 2 Ornamental woody plants: 1 Master label Application interval ( days) 14 Master label Depth of incorporation ( cm) 0 Master label aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba bNo study available on the adsorption/ desorption coefficient ( lowest non sand Kd).  B 4 Table B 2. Surface water environmental concentrations ( EECs) for drinking water risk assessment for naptalam generated from FIRST.

Surface water concentrations ( ppb)

Crop Peak, 24 hour Annual average Cucurbitsa 685.5 250.7 Ornamental woody plants 716.7 262 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba.

Table B 3. Summary of crop application scenario and EECs of naptalam obtained from GENEEC2.

Crop Application rate ( lb a. i./ A) Maximum # of applications EEC ( ppb)

Peak 21 day 60 day Cucurbitsa 4 2 452.4 442.2 423.1 Ornamental woody plants 8 1 470.7 460.1 440.2 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba.

2. Groundwater Modeling a. Background Information on SCI GROW Version 2.3 Groundwater concentrations were estimated using the Tier 1 model SCI GROW Version 2.3. SCIGROW provides a groundwater screening exposure value to be used in determining the potential risk to human health from drinking water contaminated with the pesticide. Since the SCI GROW concentrations are likely to be approached in only highly vulnerable aquifers, which constitute a very small percentage of drinking water sources, it is not appropriate to use SCI GROW for national or regional exposure estimates.

SCI GROW estimates likely groundwater concentrations if the pesticide is used at the maximum allowable rate in areas where groundwater is exceptionally vulnerable to contamination. In most cases, a large majority of the use area will have groundwater that is less vulnerable to contamination than the areas used to derive the SCI GROW estimate.  B 5 b. Model Inputs and Results SCI GROW was run for naptalam for row crops. Input values for naptalam are presented in Table B 4. The modeling results of naptalam by SCI GROW are summarized in Table B 5. The peak 24 hour concentration is 3.3 ppb.

Table B 4. Input parameters used in SCI GROW.

Input variable Parameter value Comment Application rate ( lbs a. i./ A) Curcurbitsa: 4 Ornamental woody plants: 8 Proposed label Maximum applications per year Curcurbitsa: 2 Ornamental woody plants: 1 Proposed label Koc ( mL/ g) 20 Weber, 1994 Aerobic soil metabolism half life ( days) 36.7 MRID 41427201 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba Table B 5. Ground water concentrations of naptalam estimated using SCIGROW v. 2.3.

Crop Peak 24 hour Concentration ( ppb)

Cucurbitsa ( 4 lbs a. i./ A, 2 applications, 14 day interval) 11.1 Ornamental woody plants ( 8 lbs a. i./ A, 1 application) 11.1 aCucumber, watermelon, muskmelon, cantaloupe, honeydew melon, Persian melon, casaba  B 6 RUN No. 1 FOR naptalam sodium ON cucurbits * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  4.000( 7.662) 2 14 20.0******* AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  110.00 0 N/ A 6.20 768.80 220.00 171.05 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.0 AUG 1, 2001  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  685.548 250.739 FIRST v. 1.0 Model Output  B 7 SCIGROW VERSION 2.3 ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U. S. ENVIRONMENTAL PROTECTION AGENCY SCREENING MODEL FOR AQUATIC PESTICIDE EXPOSURE SciGrow version 2.3 chemical: naptalam sodium time is 9/ 30/ 2004 10: 25: 46  Application Number of Total Use Koc Soil Aerobic rate ( lb/ acre) applications ( lb/ acre/ yr) ( ml/ g) metabolism ( days)  4.000 2.0 8.000 2.00E+ 01 36.7  groundwater screening cond ( ppb) = 1.11E+ 01 ************************************************************************ SCI GROW Version 2.3 Model Output  B 8 GENEEC2 Model Output RUN No. 34 FOR naptalam ON curcubits * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE NO SPRAY INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) ( FT) ( IN)  4.000( 7.662) 2 14 20.0******* AERL_ B( 13.0) .0 .0 FIELD AND STANDARD POND HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( POND) ( POND EFF) ( POND) ( POND)  110.00 0 N/ A 6.20 768.80 220.00 171.05 GENERIC EECs ( IN MICROGRAMS/ LITER ( PPB)) Version 2.0 Aug 1, 2001  PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC  452.40 450.94 442.24 423.08 409.11  C 1 APPENDIX C. Terrestrial Exposure Model ( ELL FATE)   Inputs, Results, Output The model output from ELL FATE for naptalam is in the attached Microsoft Excel spreadsheet Naptalam ELLFATE Version 1.4.

Kenaga Estimates and ELL FATE Model   Explanation Hoerger and Kenaga estimates ( 1972) as modified by Fletcher, Nellessen, and Pfleeger ( 1994) were used to approximate the residues on plants and insects. Hoerger Kenaga categories represent preferred foods of various terrestrial vertebrates: fruits and bud and shoot tips of leafy crops are preferred by upland game birds; leaves and stems of leafy crops are consumed by hares and hoofed mammals; seeds, seed pods and grasses are consumed by rodents; and insects are consumed by various birds, mammals, reptiles and terrestrial phase amphibians. Terrestrial vertebrates also may be exposed to pesticides applied to soil by ingesting pesticide granules and/ or pesticide laden soil when foraging. Rich in minerals, soil comprises 5 to 30% of dietary intake by many wildlife species ( Beyer and Conner, 1994).

Hoerger Kenaga pesticide environmental concentration estimates ( EECs) were based on residue data correlated from more than 20 pesticides on more than 60 crops. Representative of many geographic regions ( seven states) and a wide array of cultural practices, Hoerger Kenaga estimates also considered differences in vegetative yield, surface/ mass ratio, and interception factors. In 1994, Fletcher, Nellessen, and Pfleeger reexamined the Hoerger Kenaga simple linear model ( y= B1x, where x= application rate and y= pesticide residue in ppm) to determine whether the terrestrial EECs were accurate. They compiled a data set of pesticide day 0 and residue decay data involving 121 pesticides ( 85 insecticides, 27 herbicides, and 9 fungicides from 17 different chemical classes) on 118 species of plants. They found that Hoerger Kenaga estimates needed only minor modifications to elevate the predictive values for forage and fruit categories from 58 to 135 ppm and from 7 to 15 ppm, respectively. Otherwise, the Hoerger Kenaga estimates were accurate in predicting the maximum residue values after a 1 lb ai/ A application. Mean values represent the arithmetic mean of values from samples collected the day of pesticide treatment. These values, summarized in Table C 1, are the predicted 0 day maximum and mean residues of a pesticide that may be expected to occur on selected avian, mammalian, reptilian, or terrestrial phase amphibian food items immediately following a direct single application at a 1 lb ai/ A application rate. For pesticides applied as a nongranular product ( e. g., liquid, dust), the EECs on food items following product application are compared to LC50 values to assess risk.

Spreadsheet based Terrestrial Exposure Values A first order decay assumption is used to determine the concentration at each day after initial application based on the concentration resulting from the initial and additional applications. The decay is calculated from the standard first order rate equation:

CT = Cie kT or in integrated form: ln ( CT/ Ci) =  kT Where:

CT = concentration at time T on day zero.  C 2 Ci = concentration in parts per million ( ppm) present initially ( on day zero) on the surfaces.

Ci = is calculated based on Kenaga and Fletcher by multiplying the application rate, in pounds active ingredient per acre, by 240 for short grass, 110 for tall grass, 135 for broad leaf plants/ insects, and 15 for seeds. A similar approach is used to calculate mean residues ( see Table C 1). Additional applications are converted from pounds active ingredient per acre to ppm on the plant surface and the additional mass is added to the mass of the chemical still present on the surfaces on the day of application.

k = degradation rate constant determined from studies of hydrolysis, photolysis, microbial degradation, etc. Since degradation rate is generally reported in terms of half life, the rate constant is calculated from the input half life ( k = ln 2/ T1/ 2) instead of being input directly. Choosing which process controls the degradation rate and which half life to use in terrestrial exposure calculations is open for debate and should be done by a qualified scientist.

T = time, in days, since the start of the simulation. The initial application is on day 0. The simulation is set to run for 365 days.

ELL FATE calculates the maximum and mean residue concentrations on each type of surface on a daily interval for one year.

Table C 1. Kenaga values used in ELL FATE ( 2004) Version 1.4.

Foliage type Maximum residues Mean residues Short grass 240 85 Tall grass 110 36 Broadleaf plants and small insects 135 45 Fruits/ pods/ large insects 15 7 Literature Cited Beyer and Conner. 1994 ELL FATE. 2004. Terrestrial Exposure and Risk Model Version 1.4. April 7, 2004. Environmental Fate and Effects Division, Office of Pesticide Programs, U. S. Environmental Protection Agency, Washington, D. C.

Fletcher, JS; Nellessen, JE; Pfleeger, TG. 1994. Literature review and evaluation of the EPA food chain ( Kenaga) Nomogram, an instrument for estimating pesticide residues on plants. Environ Toxicol Chem  C 3 13( 9): 1383  1391.

Hoerger F; Kenaga, EE. 1972. Pesticide Residues on Plants: Correlation of Representative Data as a Basis for Estimation of Their Magnitude in the Environment. Agricultural Department, Dow Chemical Corporation, Midland, MI. 18 pgs.  D 1 APPENDIX D. TerrPlant Model   Inputs, Results, Output No plant toxicity data was submitted, therefore, TerrPlant was not run.  E 1 APPENDIX E. Ecological Effects Data I. Toxicity to Terrestrial Animals a. Birds, Acute and Subacute One acute oral toxicity study using the technical grade of the active ingredient ( TGAI) is required to establish the toxicity of naptalam to birds. The preferred test species is either mallard duck ( a waterfowl) or bobwhite quail ( an upland gamebird). Results of these studies are tabulated in Table E 1.

Table E 1. Avian acute oral toxicity.

Species % a. i. LD50 ( mg/ kg bw) Toxicity Category MRID Number Study Classificationa Mallard duck ( Anas platyrhynchos) 94 > 4,640 Practically nontoxic GS 0183 01 Core aCore: study satisfies guideline; Supplemental: study is scientifically sound, but does not satisfy guideline The data that were submitted show that the LD50 values fall in the range of > 2,000 mg/ kg, therefore, naptalam is categorized as practically non toxic to avian species on an acute oral basis, therefore, Guideline 71 1 is fulfilled.

Two subacute dietary studies using the TGAI are required to establish the toxicity of naptalam to birds. The preferred test species are mallard duck and bobwhite quail. Results of these tests are tabulated in Table E 2.

Table E 2. Avian subacute dietary toxicity.

Species % a. i. LC50 ( mg/ kg diet) a Toxicity Category MRID Number Study Classificationb Northern bobwhite quail ( Colinus virginianus) 94 > 10,000 Practically non toxic 00082969 Core Mallard duck ( Anas platyrhynchos) 94 > 10,000 Practically non toxic 00108853 Core a5 day dietary exposure followed by additional 3 day observation period. bCore: study satisfies guideline; Supplemental: study is scientifically sound, but does not satisfy guideline.  E 2 The data that were submitted show that the LC50 values fall in the range of > 5,000 ppm, therefore, naptalam is categorized as practically non toxic to avian species on a subacute dietary basis. Therefore, Guideline 71 2 is fulfilled.

b. Birds, Chronic Avian reproduction studies using the TGAI are required for naptalam because the following conditions are met: ( 1) birds may be subject to repeated or continuous exposure to the pesticide, especially preceding or during the mating season; ( 2) the pesticide is stable in the environment to the extent that potentially toxic amounts may persist in animal feed; and ( 3) the pesticide is stored or accumulated in plant or animal tissues. The preferred test species are mallard duck and bobwhite quail.

c. Mammals, Acute and Chronic Wild mammal testing is required on a case by case basis, depending on the results of lower tier laboratory mammalian studies, intended use pattern and pertinent environmental fate characteristics. In most cases, rat or mouse toxicity values obtained from the Agency's Health Effects Division ( HED) substitute for wild mammal testing. The toxicity values for mammalian oral, dermal, and inhalation toxicity tests are reported in Table E 3.

Table E 3. Mammalian toxicity.

Species Study Type/ Doses Results MRID No.

Rat ( Rattus norvegicus) Acute oral LD50 = 1,700 mg/ kg/ day ( salt) LD50 > 8,192 mg/ kg/ day ( acid) 29172 76205 Rat ( Rattus norvegicus) Acute dermal   rat LD50 > 2 g/ kg 00068402 Rat ( Rattus norvegicus) Acute inhalation   rat LC50 > 2.0 mg/ L 43936401 Rabbit Acute eye irritation   rabbit Slight irritation 00078530 Rabbit Acute dermal irritation   rabbit Non irritant 00060403 Guinea pig ( Cavia porcellus) Skin sensitization   Guinea pig Dermal sensitizer 00015185 Rat ( Rattus norvegicus) 90 Day oral toxicity rat; 0, 25, 50, 250 mg/ kg/ day NOAEL = 1,000 ppm ( 50 mg/ kg/ day) LOAEL = 5,000 ppm ( 250 mg/ kg/ day) based on reduced body weight gain, reduced food efficiency, and decreased organ weights. 00106276 Table E 3. Mammalian toxicity.

Species Study Type/ Doses Results MRID No.

 E 3 Rat ( Rattus norvegicus) 90 Day oral toxicity dog; Males: 0, 11.4, 29.7, 124.7 mg/ kg/ day Females: 0, 9.7, 29.9, 123.6 mg/ kg/ day NOAEL = 1,000 ppm ( 29.7  29.9 mg/ kg/ day) LOAEL = 3,000 ppm ( 123.6  124.7 mg/ kg/ day) based on reduced body weight gains, reduced food efficiency, and increased absolute and relative liver weights. 00106277 Dog ( Canis familiarus) 90 Day oral toxicity; 0, 5.3, 25.8, 121 mg/ kg/ day NOAEL = 200 ppm ( 5.3 mg/ kg/ day) LOAEL = females: 1,000 ppm ( 25.8 mg/ kg/ day); males 5,000 ppm ( 121 mg/ kg/ day) based on liver weights, increased enzyme activity and bilirubin. 41057501 Rat ( Rattus norvegicus) Teratology study in the rat; 0, 15, 115, 500 mg/ kg/ day Maternal NOAEL = 15 mg/ kg/ day LOAEL = 115 mg/ kg/ day based on reduced body weight gain ( minimal and not supported by other observations). Developmental NOAEL = 115 mg/ kg/ day LOAEL = 500 mg/ kg/ day based on reduced fetal weights, increased skeletal observations. 000106320 Rabbit Teratology study in rabbits Maternal NOAEL = 200 mg/ kg/ day LOAEL = 650 mg/ kg/ day based on reduced body weight gain, mortality, and clinical observations. Developmental NOAEL = 200 mg/ kg/ day LOAEL = 650 mg/ kg/ day based on increased skeletal observations. 00157186 Table E 3. Mammalian toxicity.

Species Study Type/ Doses Results MRID No.

 E 4 Rat ( Rattus norvegicus) Multigeneration reproduction and fertility study in the rat; 0, 6, 30, 150 mg/ kg/ day Parental/ Systemic NOAEL = 600 ppm ( 30 mg/ kg/ day) LOAEL = 3,000 ppm ( 150 mg/ kg/ day) based on reduced body weights. Reproductive NOAEL > 3,000 ppm ( 150 mg/ kg/ day) LOAEL > 3,000 ppm ( 150 mg/ kg/ day) Offspring NOAEL = 600 ppm ( 30 mg/ kg/ day) LOAEL = 3,000 ppm ( 150 mg/ kg/ day) based on reduced mean pup body weights. 00031684 Rat ( Rattus norvegicus) 104 Week chronic toxicity in the rat; 0, 5.6, 27, 140 mg/ kg/ day NOAEL > 140 mg/ kg/ day LOAEL > 140 mg/ kg/ day. 00077053 Dog ( Canis familiaris) 12 Month oral chronic toxicity study in the dog; 0, 5.3, 25.8, 121 mg/ kg/ day NOAEL = 1,000 ppm ( 25.8 mg/ kg/ day) LOAEL = 5,000 ppm ( 121 mg/ kg/ day) based on increased liver weights, increased levels of alkaline phosphatase and bilirubin. 41057501 Rat ( Rattus norvegicus) Metabolism and pharmacokinetics   rat 14C naptalam was rapidly absorbed, distributed and excreted with 7 day recovery of 85% 40274502 1Core: study satisfies guideline; Supplemental: study is scientifically sound, but does not satisfy guideline; NA: not available Based on these results naptalam is categorized as slightly toxic to small mammals on an acute oral basis ( LD50 = 1,700 mg/ kg bw) and the potential for chronic reproductive effects appears to be low. In a multigeneration reproduction study in the rat ( Rattus norvegicus) possible systemic toxicity was observed in the offspring in the form of statistically significant reduction in the mean pup body weights in the highdose group ( 3,000 mg/ kg in the diet or 150 mg/ kg bw). This is equal to the lowest observed adverse effect level ( LOAEL). The no observed adverse effect level ( NOAEL) for naptalam for reproductive effects was 600 mg/ kg diet or 30 mg/ kg bw ( MRID 00031684).  E 5 d. Terrestrial Insects, Honeybee Acute A honey bee acute contact study using the TGAI is required for naptalam because its use on crops will result in honey bee exposure. The acute contact LD50, using the honey bee ( Apis mellifera) is an acute contact, single dose laboratory study designed to estimate the quantity of toxicant required to cause 50% mortality in a test population. The TGAI is administered by one of two methods: whole body exposure to technical pesticide in a non toxic dust diluent; or topical exposure to technical pesticide via microapplicator The median lethal dose ( LD50) is expressed in micrograms of active ingredient per bee (: g a. i./ bee). Results of this test are tabulated below ( Table E 4). Toxicity category descriptions for honey bee acute contact toxicity are from Atkins ( 1981):

The following toxicity category descriptions were developed by Atkins ( 1981) and have been used by EFED to characterize honey bee acute contact toxicity values ( EPA, 2004):

LD50 ( : g a. i./ bee) Toxicity Category < 2 Highly toxic 2 < 11 Moderately toxic > 11 Practically nontoxic Table E 4. Honey bee acute contact toxicity.

Species % a. i. 48 hour LD50 ( µ g/ bee) Category MRID Number Study Classificationa Honey bee ( Apis mellifera) Technical 113.2 Practically non toxic 00028772 Core aCore: study satisfies guideline; Supplemental: study is scientifically sound, but does not satisfy guideline.

The data that were submitted show that the LD50 for the honey bee falls in the range of > 11 : g/ bee, therefore, naptalam is categorized as practically non toxic to the honeybee on an acute contact basis. Therefore, Guideline 141 1 is fulfilled. Further acute oral toxicity testing and foliar residue toxicity testing with the honeybee were not required. A honey bee foliar residue toxicity study is required on an end use product for any pesticide intended for outdoor application when the proposed use pattern indicates that honey bees may be exposed to the pesticide and when the formulation contains one or more active ingredients having an acute contact honey bee LD50 which falls in the moderately toxic or highly toxic range.  E 6 II. Toxicity to Freshwater Animals a. Freshwater Fish, Acute Two freshwater fish toxicity studies using the TGAI are required to establish the acute toxicity of naptalam to fish. The preferred test species are rainbow trout ( Oncorhynchus mykiss) ( a coldwater fish) and bluegill sunfish ( Lepomis macrochirus) ( a warmwater fish). Results of these tests are tabulated below in Table E 5.

Table E 5. Freshwater fish acute toxicity.