Pesticide Risk Assessment

What is FIFRA? Federal Insecticide, Fungicide, and Rodenticide Act Federal Insecticide, Fungicide, and Rodenticide Act Requires pesticides sold or used in U.S. to be registered by EPA Requires pesticides sold or used in U.S. to be registered by EPA EPA registration standard: will not cause “unreasonable adverse effects on the environment” EPA registration standard: will not cause “unreasonable adverse effects on the environment”

FIFRA REGISTRATION Section 3 - Authorizes EPA to register new pesticide products Section 3 - Authorizes EPA to register new pesticide products Section 4 - Reregistration of pesticides by EPA to ensure they meet current standards Section 4 - Reregistration of pesticides by EPA to ensure they meet current standards Section 18 - Emergency use requests can be granted by EPA for unregistered pesticide uses Section 18 - Emergency use requests can be granted by EPA for unregistered pesticide uses Section 24(C) - Special local needs requests can be granted by EPA for new uses of registered products Section 24(C) - Special local needs requests can be granted by EPA for new uses of registered products

EPA-OPP Standard Evaluation Procedure for Ecological Risk Assessment Assumes risk is a function of toxicity and exposure Assumes risk is a function of toxicity and exposure RQ = Estimated Environmental Concentration / Toxicity Endpoint RQ = Estimated Environmental Concentration / Toxicity Endpoint RQ compared to levels of concern (LOC’s) RQ compared to levels of concern (LOC’s)

Toxicity Tests Terrestrial Animals TestSpeciesExposureEndpoint LD50Bobwhite/Mallard Single oral Mortality LC50Bobwhite/Mallard 5-d Dietary Mortality Repro.Bobwhite/Mallard10-wkDietary LOEC, NOEC

Toxicity Tests: Aquatic Animals TestSpeciesExposureEndpoint LC50 Rainbow, bluegill, sheepshead 96 h Mortality LC50 Daphnia, mysid, eastern oyster h Mortality ELS Fathead, Rainbow, Sheepshead d LOEC,NOEC LifeCycle Daphnia, mysid, fish spp d LOEC,NOEC

Toxicity Tests: Terrestrial Invertebrate Honey bee Honey bee Acute oral LD50 Acute oral LD50 Acute dermal LD50 Acute dermal LD50 Residue studies LD50 Residue studies LD50

Toxicity Test: Plants Aquatic plants Aquatic plants Blue-green and green algae (EC50) Blue-green and green algae (EC50) Marine and freshwater diatom (EC50) Marine and freshwater diatom (EC50) Duckweed (EC50) Duckweed (EC50) Terrestrial plants (EC25, NOEC) Terrestrial plants (EC25, NOEC) Six dicots and four monocots (crops) Six dicots and four monocots (crops) Root-shoot length, weight, visual Root-shoot length, weight, visual

Other Sources of Toxicity Information Registrant generated test to satisfy registration requirements for other countries Registrant generated test to satisfy registration requirements for other countries OECD Studies: OECD Studies: Beneficial arthropods Beneficial arthropods Soil microorganisms Soil microorganisms Formulation/mixture studies Formulation/mixture studies Metabolite studies Metabolite studies

Human Health Toxicity Studies Rat LD50 Rat LD50 2 generation chronic rat 2 generation chronic rat 90-day sub-chronic rat 90-day sub-chronic rat Inhalation (rat/mouse) Inhalation (rat/mouse) Dermal (rabbit) Dermal (rabbit)

Other Sources of Toxicity Information Open Literature Open Literature Internet Sources (USGS acute toxicity test database, EXTOXNET, PAN pesticide database, WHO/FAO pesticide data sheets) Internet Sources (USGS acute toxicity test database, EXTOXNET, PAN pesticide database, WHO/FAO pesticide data sheets) EPA-OPP “One-liner” ecotoxicity and environmental fate databases EPA-OPP “One-liner” ecotoxicity and environmental fate databases

Laboratory Environmental Fate Studies Laboratory Environmental Fate Studies Aerobic Soil Metabolism - rate of degradation by soil microorganisms Aerobic Soil Metabolism - rate of degradation by soil microorganisms Hydrolysis - chemical reaction with water forming new molecule (often pH dependent) Hydrolysis - chemical reaction with water forming new molecule (often pH dependent) Aqueous Photolysis - breakdown of molecules in water through the absorption of light Aqueous Photolysis - breakdown of molecules in water through the absorption of light Aerobic and Anaerobic Aquatic Metabolism - rate of metabolism in aqueous environment with and without oxygen. Aerobic and Anaerobic Aquatic Metabolism - rate of metabolism in aqueous environment with and without oxygen.

Laboratory Environmental Fate Studies (continued) Kd and Koc - rate of soil adsorption Kd and Koc - rate of soil adsorption Bioconcentration Factor (BCF) - Ratio of concentration in organism (fish) compared to surrounding medium (water) Bioconcentration Factor (BCF) - Ratio of concentration in organism (fish) compared to surrounding medium (water)

Field Environmental Fate Studies Field Dissipation - evaluate pesticide mobility, degradation and dissipation under actual use conditions Field Dissipation - evaluate pesticide mobility, degradation and dissipation under actual use conditions agricultural, aquatic, forestry agricultural, aquatic, forestry Field Volatility - evaluate pesticide movement when volatilization is concern Field Volatility - evaluate pesticide movement when volatilization is concern Dislodgeable residue Dislodgeable residue

Chemical/Physical Studies Vapor pressure - measure of a chemicals volatility Vapor pressure - measure of a chemicals volatility Solubility - measure of ability to dissolve in a solvent (water) Solubility - measure of ability to dissolve in a solvent (water) Henry’s Law Constant - ratio of vapor pressure to water solubility Henry’s Law Constant - ratio of vapor pressure to water solubility Octanol-water partition coefficient (Kow) - ratio of partitioning in octanol to water Octanol-water partition coefficient (Kow) - ratio of partitioning in octanol to water

EPA-OPP Exposure Analysis Terrestrial: Terrestrial: Kenaga Nomogram Kenaga Nomogram Monitoring Data Monitoring Data Aquatic: Aquatic: GENEEC GENEEC PRZM/EXAMS PRZM/EXAMS Monitoring Data Monitoring Data Terrestrial/Aquatic: Terrestrial/Aquatic: AgDrift AgDrift

Kenaga Nomogram Review Dietary exposure model for liquid broadcast applications Dietary exposure model for liquid broadcast applications Determines maximum and median concentrations on various food items Determines maximum and median concentrations on various food items Residue based on application rate and structure of plant/insect Residue based on application rate and structure of plant/insect Residues independent of application method Residues independent of application method

Granular, Bait, and Treated Seed Exposure Applications In-furrow applications assume 1% of granules, bait or seed unincorporated In-furrow applications assume 1% of granules, bait or seed unincorporated Incorporated banded treatments assume 15% material unincorporated Incorporated banded treatments assume 15% material unincorporated Broadcast treatment w/o incorporation assumes 100% of granules, bait, seed unincorporated Broadcast treatment w/o incorporation assumes 100% of granules, bait, seed unincorporated

Terrestrial Plant Exposure Analysis Runoff based on solubility Runoff based on solubility Drift based on standard assumptions for ground (1%) and aerial (5%) applications Drift based on standard assumptions for ground (1%) and aerial (5%) applications Scenario based on runoff from 1-ha to adjacent hectare for terrestrial plants Scenario based on runoff from 1-ha to adjacent hectare for terrestrial plants Scenario based on runoff from 10-ha to adjacent hectare for semi-aquatic plants Scenario based on runoff from 10-ha to adjacent hectare for semi-aquatic plants

AgDrift Model Summary Model based on field and wind tunnel studies to determine drift from different application methods Model based on field and wind tunnel studies to determine drift from different application methods Simulates ground, orchard air blast and aerial applications Simulates ground, orchard air blast and aerial applications Predicts off-site terrestrial and aquatic concentrations into standard or user- defined waterbodies Predicts off-site terrestrial and aquatic concentrations into standard or user- defined waterbodies

Factors that affect drift Droplet size distribution Droplet size distribution Wind speed/direction Wind speed/direction Release height Release height Application method Application method Environmental factors (temperature, humidity) Environmental factors (temperature, humidity)

GENEEC Input Parameters Application Rate Application Rate Koc Koc Application Method Application Method # of applications # of applications Application Interval Application Interval Depth of Incorporation Depth of Incorporation Aerobic Aquatic Metabolism Aerobic Aquatic Metabolism Solubility Solubility Aquatic Photolysis Aquatic Photolysis Hydrolysis Hydrolysis Aerobic Soil Metabolism Aerobic Soil Metabolism

GENEEC Aquatic Screening Model Assumptions Applications occur on a 10 ha field that drains into a one hectare pond 2-m in depth Applications occur on a 10 ha field that drains into a one hectare pond 2-m in depth No buffer between the pond and treated field No buffer between the pond and treated field Runoff is from a single large rainfall event over a 24-hour period Runoff is from a single large rainfall event over a 24-hour period Soil type is considered a high runoff soil (MS silt loam) Soil type is considered a high runoff soil (MS silt loam) Drift contribution: Drift contribution: Based on contributions from AgDrift Based on contributions from AgDrift

Atrazine estimated environmental concentrations (1 lb/ai)

PRZM/EXAMS Aquatic Exposure Model Site specific model that determines pesticide load from agricultural applications Site specific model that determines pesticide load from agricultural applications Each simulation is conducted using 36 years of rainfall data to determine variability in loading Each simulation is conducted using 36 years of rainfall data to determine variability in loading Calculates edge of field pesticide loadings in surface water and sediment Calculates edge of field pesticide loadings in surface water and sediment

PRZM/EXAMS Aquatic Exposure Model Environmental fate model that simulates the process that occur in the water body Environmental fate model that simulates the process that occur in the water body Steady state model that has a constant volume Steady state model that has a constant volume Calculates peak maximum, 96-hour, 21- day and 60-day average. Calculates peak maximum, 96-hour, 21- day and 60-day average. The 1 in 10 year maximum value is used in calculating risk quotient values The 1 in 10 year maximum value is used in calculating risk quotient values

Use of Monitoring Data in Pesticide Risk Assessment Typically used for currently registered pesticides (reregistration, special review) Typically used for currently registered pesticides (reregistration, special review) Sources: Sources: NAWQA – USGS NAWQA – USGS open literature open literature registrants registrants Considerations for use: Considerations for use: temporal and spatial sampling temporal and spatial sampling storm events vs. base flow storm events vs. base flow

Temporal variability of atrazine and chlorpyrifos in water and sediment

Risk Presumption for Terrestrial Animals Risk Presumption RQLOC Acute High Risk EEC/LC50 or LD50/ft Acute Restricted Use EEC/LC50 or LD50/ft Acute Endangered Species EEC/LC50 or LD50/ft Chronic RQ EEC/NOEC1

LOC and Dose Response

Risk Presumption for Aquatic Animals Risk Presumption RQLOC Acute High Risk EEC/LC50 or EC Acute Restricted Use EEC/LC50 or EC Acute Endangered Species EEC/LC50 or EC Chronic RQ EEC/NOEC1

Risk Presumption for Terrestrial Plants Risk Presumption RQLOC Terrestrial and semiaquatic plants Acute high risk EEC/EC251 Acute ES EEC/NOEC1 Aquatic plants Acute high risk EEC/EC501 Acute ES EEC/NOEC1

Exceedance of LOC’s in the Screening Assessment Request additional effects data Request additional effects data Request additional environmental fate data Request additional environmental fate data Ex. aerobic aquatic metabolism, foliar dissipation Ex. aerobic aquatic metabolism, foliar dissipation Use higher tier modeling/monitoring to refine exposure analysis and provide site specific exposure distribution Use higher tier modeling/monitoring to refine exposure analysis and provide site specific exposure distribution

NAWQA Maximum Atrazine Concentrations for 40 Agricultural Sites Exceedence % % Sites w/ Atrazine Concs >= Y Measured Concenrations (ug/L) * Mortality in Phytoplankton & Macrophytes Estimated to Occur at 32 µg/L * Invertebrate Populations Likely to be Reduced at 22 µg/L * Mortality to Macrophytes Estimated to Occur at 18 µg/L * Reduction in Primary Production Likely to Occur at 10 µg/L * Reduction in Primary Production Likely to Occur at 2.62 µg/L and Reductions in Primary Productivity & Macrophytes Estimated to Occur at 2.3 µg/L Source: Reregistration Eligibility Decision: Environmental Fate and Effects Chapter

EPA-OPP Risk Mitigation for Fish and Wildlife Eliminate use on specific crop Eliminate use on specific crop Buffer zones Buffer zones Time of application Time of application Application method and rates Application method and rates Number of applications Number of applications Spray drift best management practices Spray drift best management practices

OPP Endangered Species Protection Program (ESPP) Goal is to implement mitigation measures to eliminate adverse impact to listed spp. Goal is to implement mitigation measures to eliminate adverse impact to listed spp. Currently ESPP defers to “county bulletins” Currently ESPP defers to “county bulletins” Program in place since 1989 Program in place since 1989 Voluntary BMPs for listed species Voluntary BMPs for listed species Very few county bulletins complete Very few county bulletins complete Service has not consulted on county bulletins Service has not consulted on county bulletins Service currently working with OPP to review ESPP Service currently working with OPP to review ESPP