Pesticide Risk AssessmentPesticide Risk Assessment

What is FIFRA?What is FIFRA?

Federal Insecticide, Fungicide, and Federal Insecticide, Fungicide, and Rodenticide ActRodenticide Act

Requires pesticides sold or used in Requires pesticides sold or used in U.S. to be registered by EPA U.S. to be registered by EPA

EPA registration standard: will not EPA registration standard: will not cause “unreasonable adverse effects cause “unreasonable adverse effects on the environment”on the environment”

FIFRA REGISTRATIONFIFRA REGISTRATION

Section 3 - Authorizes EPA to register new Section 3 - Authorizes EPA to register new pesticide products pesticide products

Section 4 - Reregistration of pesticides by Section 4 - Reregistration of pesticides by EPA to ensure they meet current standardsEPA to ensure they meet current standards

Section 18 - Emergency use requests can Section 18 - Emergency use requests can be granted by EPA for unregistered be granted by EPA for unregistered pesticide usespesticide uses

Section 24(C) - Special local needs requests Section 24(C) - Special local needs requests can be granted by EPA for new uses of can be granted by EPA for new uses of registered productsregistered products

EPA-OPP Standard Evaluation EPA-OPP Standard Evaluation Procedure for Ecological Risk Procedure for Ecological Risk

AssessmentAssessment Assumes risk is a function of toxicity Assumes risk is a function of toxicity

and exposureand exposure RQ = Estimated Environmental RQ = Estimated Environmental

Concentration / Toxicity EndpointConcentration / Toxicity Endpoint RQ compared to levels of concern RQ compared to levels of concern

(LOC’s)(LOC’s)

Toxicity Tests Toxicity Tests Terrestrial Animals Terrestrial Animals

TestTest SpeciesSpecies ExposureExposure EndpointEndpoint

LD50LD50 Bobwhite/Bobwhite/

MallardMallardSingle Single oraloral

MortalityMortality

LC50LC50 Bobwhite/Bobwhite/

MallardMallard5-d 5-d DietaryDietary

MortalityMortality

Repro.Repro. Bobwhite/Bobwhite/

MallardMallard10-wk10-wk

Dietary Dietary LOEC, LOEC, NOECNOEC

Toxicity Tests: Aquatic Toxicity Tests: Aquatic Animals Animals

TestTest SpeciesSpecies ExposurExposuree

EndpointEndpoint

LC5LC500

Rainbow, Rainbow, bluegill, bluegill, sheepsheadsheepshead

96 h96 h MortalityMortality

LC5LC500

Daphnia, Daphnia, mysid, eastern mysid, eastern oysteroyster

48-96 h48-96 h MortalityMortality

ELSELS Fathead, Fathead, Rainbow, Rainbow, SheepsheadSheepshead

30-100 30-100 dd

LOEC,LOEC,

NOECNOEC

Life Life

CyclCyclee

Daphnia, Daphnia, mysid, fish spp.mysid, fish spp.

21-300 21-300 dd

LOEC,LOEC,

NOECNOEC

Toxicity Tests: Terrestrial Toxicity Tests: Terrestrial InvertebrateInvertebrate

Honey beeHoney bee Acute oral LD50Acute oral LD50 Acute dermal LD50 Acute dermal LD50 Residue studies Residue studies

LD50LD50

Toxicity Test: PlantsToxicity Test: Plants

Aquatic plantsAquatic 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, visualRoot-shoot length, weight, visual

Other Sources of Toxicity Other Sources of Toxicity InformationInformation

Registrant generated test to Registrant generated test to satisfy registration requirements satisfy registration requirements for other countriesfor other countries OECD Studies:OECD Studies:

Beneficial arthropodsBeneficial arthropods Soil microorganismsSoil microorganisms Formulation/mixture studiesFormulation/mixture studies Metabolite studiesMetabolite studies

Human Health Toxicity Human Health Toxicity StudiesStudies

Rat LD50Rat LD50 2 generation chronic rat2 generation chronic rat 90-day sub-chronic rat90-day sub-chronic rat Inhalation (rat/mouse)Inhalation (rat/mouse) Dermal (rabbit)Dermal (rabbit)

Other Sources of Toxicity Other Sources of Toxicity InformationInformation

Open LiteratureOpen Literature Internet Sources (USGS acute toxicity Internet Sources (USGS acute toxicity

test database, EXTOXNET, PAN test database, EXTOXNET, PAN pesticide database, WHO/FAO pesticide database, WHO/FAO pesticide data sheets)pesticide data sheets)

EPA-OPP “One-liner” ecotoxicity and EPA-OPP “One-liner” ecotoxicity and environmental fate databases environmental fate databases www.epa.gov/pesticides/www.epa.gov/pesticides/

Laboratory EnvironmentalLaboratory Environmental Fate Studies Fate Studies

Aerobic Soil Metabolism - rate of degradation Aerobic Soil Metabolism - rate of degradation by soil microorganismsby soil microorganisms

Hydrolysis - chemical reaction with water Hydrolysis - chemical reaction with water forming new molecule (often pH dependent)forming new molecule (often pH dependent)

Aqueous Photolysis - breakdown of molecules Aqueous Photolysis - breakdown of molecules in water through the absorption of lightin water through the absorption of light

Aerobic and Anaerobic Aquatic Metabolism - Aerobic and Anaerobic Aquatic Metabolism - rate of metabolism in aqueous environment rate of metabolism in aqueous environment with and without oxygen.with and without oxygen.

Laboratory EnvironmentalLaboratory Environmental Fate Studies (continued) Fate Studies (continued)

Kd and Koc - rate of soil adsorption Kd and Koc - rate of soil adsorption Bioconcentration Factor (BCF) - Bioconcentration Factor (BCF) -

Ratio of concentration in organism Ratio of concentration in organism (fish) compared to surrounding (fish) compared to surrounding medium (water)medium (water)

Field Environmental Fate Field Environmental Fate StudiesStudies

Field Dissipation - evaluate pesticide Field Dissipation - evaluate pesticide mobility, degradation and dissipation mobility, degradation and dissipation under actual use conditions under actual use conditions agricultural, aquatic, forestry agricultural, aquatic, forestry

Field Volatility - evaluate pesticide Field Volatility - evaluate pesticide movement when volatilization is movement when volatilization is concern concern

Dislodgeable residueDislodgeable residue

Chemical/Physical Studies Chemical/Physical Studies

Vapor pressure - measure of a Vapor pressure - measure of a chemicals volatility chemicals volatility

Solubility - measure of ability to dissolve Solubility - measure of ability to dissolve in a solvent (water)in a solvent (water)

Henry’s Law Constant - ratio of vapor Henry’s Law Constant - ratio of vapor pressure to water solubility pressure to water solubility

Octanol-water partition coefficient (Kow) Octanol-water partition coefficient (Kow) - ratio of partitioning in octanol to water- ratio of partitioning in octanol to water

EPA-OPP Exposure AnalysisEPA-OPP Exposure Analysis

Terrestrial:Terrestrial: Kenaga Nomogram Kenaga Nomogram Monitoring DataMonitoring Data

Aquatic:Aquatic: GENEECGENEEC PRZM/EXAMSPRZM/EXAMS Monitoring DataMonitoring Data

Terrestrial/Aquatic:Terrestrial/Aquatic: AgDriftAgDrift

Kenaga Nomogram ReviewKenaga Nomogram Review

Dietary exposure model for liquid Dietary exposure model for liquid broadcast applicationsbroadcast applications

Determines maximum and median Determines maximum and median concentrations on various food itemsconcentrations on various food items

Residue based on application rate and Residue based on application rate and structure of plant/insectstructure of plant/insect

Residues independent of application Residues independent of application method method

Granular, Bait, and Treated Granular, Bait, and Treated Seed Exposure ApplicationsSeed Exposure Applications

In-furrow applications assume 1% of In-furrow applications assume 1% of granules, bait or seed unincorporatedgranules, bait or seed unincorporated

Incorporated banded treatments Incorporated banded treatments assume 15% material unincorporatedassume 15% material unincorporated

Broadcast treatment w/o Broadcast treatment w/o incorporation assumes 100% of incorporation assumes 100% of granules, bait, seed unincorporatedgranules, bait, seed unincorporated

Terrestrial Plant Exposure Terrestrial Plant Exposure AnalysisAnalysis

Runoff based on solubilityRunoff based on solubility Drift based on standard assumptions for Drift based on standard assumptions for

ground (1%) and aerial (5%) applicationsground (1%) and aerial (5%) applications Scenario based on runoff from 1-ha to Scenario based on runoff from 1-ha to

adjacent hectare for terrestrial plantsadjacent hectare for terrestrial plants Scenario based on runoff from 10-ha to Scenario based on runoff from 10-ha to

adjacent hectare for semi-aquatic plantsadjacent hectare for semi-aquatic plants

AgDrift Model SummaryAgDrift Model Summary

Model based on field and wind tunnel Model based on field and wind tunnel studies to determine drift from studies to determine drift from different application methodsdifferent application methods

Simulates ground, orchard air blast Simulates ground, orchard air blast and aerial applicationsand aerial applications

Predicts off-site terrestrial and Predicts off-site terrestrial and aquatic concentrations into standard aquatic concentrations into standard or user-defined waterbodies or user-defined waterbodies

Factors that affect driftFactors that affect drift

Droplet size distributionDroplet size distribution Wind speed/directionWind speed/direction Release heightRelease height Application methodApplication method Environmental factors (temperature, Environmental factors (temperature,

humidity)humidity)

GENEEC Input ParametersGENEEC Input Parameters

Application RateApplication Rate KocKoc Application Application

MethodMethod # of applications# of applications Application IntervalApplication Interval Depth of Depth of

IncorporationIncorporation

Aerobic Aquatic Aerobic Aquatic MetabolismMetabolism

SolubilitySolubility Aquatic PhotolysisAquatic Photolysis HydrolysisHydrolysis Aerobic Soil Aerobic Soil

MetabolismMetabolism

GENEEC Aquatic Screening GENEEC Aquatic Screening Model AssumptionsModel Assumptions

Applications occur on a 10 ha field that drains Applications occur on a 10 ha field that drains into a one hectare pond 2-m in depthinto a one hectare pond 2-m in depth

No buffer between the pond and treated fieldNo buffer between the pond and treated field Runoff is from a single large rainfall event Runoff is from a single large rainfall event

over a 24-hour periodover a 24-hour period Soil type is considered a high runoff soil (MS Soil type is considered a high runoff soil (MS

silt loam)silt loam) Drift contribution:Drift contribution:

Based on contributions from AgDrift Based on contributions from AgDrift

Atrazine estimated Atrazine estimated environmental concentrations environmental concentrations

(1 lb/ai)(1 lb/ai)

Days

0 20 40 60 80 100

Atr

azi

ne

[u

g/l]

0

2

4

6

8

10

12

Aerial (Koc = 39)Aerial (Koc = 155)Ground (Koc = 39)Ground (Koc = 155)

PRZM/EXAMS Aquatic PRZM/EXAMS Aquatic Exposure ModelExposure Model

Site specific model that determines Site specific model that determines pesticide load from agricultural pesticide load from agricultural applicationsapplications

Each simulation is conducted using 36 Each simulation is conducted using 36 years of rainfall data to determine years of rainfall data to determine variability in loadingvariability in loading

Calculates edge of field pesticide Calculates edge of field pesticide loadings in surface water and sediment loadings in surface water and sediment

PRZM/EXAMS Aquatic PRZM/EXAMS Aquatic Exposure ModelExposure Model

Environmental fate model that Environmental fate model that simulates the process that occur in the simulates the process that occur in the water bodywater body

Steady state model that has a constant Steady state model that has a constant volumevolume

Calculates peak maximum, 96-hour, Calculates peak maximum, 96-hour, 21-day and 60-day average. 21-day and 60-day average.

The 1 in 10 year maximum value is The 1 in 10 year maximum value is used in calculating risk quotient valuesused in calculating risk quotient values

Use of Monitoring Data in Use of Monitoring Data in Pesticide Risk AssessmentPesticide Risk Assessment

Typically used for currently registered Typically used for currently registered pesticides (reregistration, special review)pesticides (reregistration, special review)

Sources:Sources: NAWQA – USGSNAWQA – USGS open literatureopen literature registrants registrants

Considerations for use:Considerations for use: temporal and spatial samplingtemporal and spatial sampling storm events vs. base flowstorm events vs. base flow

Temporal variability of atrazine Temporal variability of atrazine and chlorpyrifos in water and and chlorpyrifos in water and

sedimentsediment

Risk Presumption for Risk Presumption for Terrestrial AnimalsTerrestrial Animals

Risk PresumptionRisk Presumption RQRQ LOCLOC

Acute High RiskAcute High Risk EEC/LC50 or EEC/LC50 or LD50/ftLD50/ft22

0.50.5

Acute Restricted Acute Restricted UseUse

EEC/LC50 or EEC/LC50 or LD50/ftLD50/ft22

0.20.2

Acute Acute Endangered Endangered

SpeciesSpecies

EEC/LC50 or EEC/LC50 or LD50/ftLD50/ft22

0.10.1

Chronic RQChronic RQ EEC/NOECEEC/NOEC 11

LOC and Dose ResponseLOC and Dose Response

Concentration [ppm]

0 2000 4000 6000 8000 10000 12000

% M

orta

lity

0

20

40

60

80

100

120

Pesticide APesticide B

LC50LOC

Risk Presumption for Risk Presumption for Aquatic AnimalsAquatic Animals

Risk PresumptionRisk Presumption RQRQ LOCLOC

Acute High RiskAcute High Risk EEC/LC50 or EEC/LC50 or EC50EC50

0.50.5

Acute Restricted Acute Restricted UseUse

EEC/LC50 or EEC/LC50 or EC50EC50

0.10.1

Acute Endangered Acute Endangered SpeciesSpecies

EEC/LC50 or EEC/LC50 or EC50EC50

0.050.05

Chronic RQChronic RQ EEC/NOECEEC/NOEC 11

Risk Presumption for Risk Presumption for Terrestrial PlantsTerrestrial Plants

Risk Risk PresumptionPresumption

RQRQ LOCLOC

Terrestrial and semiaquatic plantsTerrestrial and semiaquatic plants

Acute high Acute high riskrisk

EEC/EC25EEC/EC25 11

Acute ESAcute ES EEC/NOECEEC/NOEC 11

Aquatic plantsAquatic plants

Acute high Acute high riskrisk

EEC/EC50EEC/EC50 11

Acute ESAcute ES EEC/NOECEEC/NOEC 11

Exceedance of LOC’s in the Exceedance of LOC’s in the Screening AssessmentScreening Assessment

Request additional effects dataRequest additional effects data Request additional environmental fate Request additional environmental fate

datadata Ex. aerobic aquatic metabolism, foliar Ex. aerobic aquatic metabolism, foliar

dissipationdissipation Use higher tier modeling/monitoring to Use higher tier modeling/monitoring to

refine exposure analysis and provide refine exposure analysis and provide site specific exposure distributionsite specific exposure distribution

NAWQA Maximum Atrazine NAWQA Maximum Atrazine Concentrations for 40 Concentrations for 40

Agricultural SitesAgricultural Sites

0

10

20

30

40

50

60

70

80

90

100

110

120

130

0 10 20 30 40 50 60

Exceedence % % Sites w/ Atrazine Concs >= Y

Mea

sure

d C

on

cen

rati

on

s (u

g/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. 2002.

EPA-OPP Risk Mitigation for EPA-OPP Risk Mitigation for Fish and WildlifeFish and Wildlife

Eliminate use on specific cropEliminate use on specific crop Buffer zonesBuffer zones Time of applicationTime of application Application method and ratesApplication method and rates Number of applicationsNumber of applications Spray drift best management Spray drift best management

practicespractices

METHAMIDAPHOS

0

50

100

150

200

250

300

350

400

450

1 8 15 22 29

Days

Co

ncen

trati

on

(p

pm

)

grass <20cm

grass >20 cm

leaves, insects

seeds, fruits

Avian LC50 (42 ppm)

Egg shell effects (5 ppm)

Mammal survival(33 ppm)

.

OPP Endangered Species OPP Endangered Species Protection Program (ESPP)Protection Program (ESPP)

Goal is to implement mitigation measures Goal is to implement mitigation measures to eliminate adverse impact to listed spp.to eliminate adverse impact to listed spp.

Currently ESPP defers to “county bulletins”Currently ESPP defers to “county bulletins” Program in place since 1989Program in place since 1989 Voluntary Voluntary BMPs for listed speciesBMPs for listed species Very few county bulletins completeVery few county bulletins complete Service has not consulted on county bulletinsService has not consulted on county bulletins

Service currently working with OPP to Service currently working with OPP to review ESPPreview ESPP