Hotze Wijnja, Ph.D . Division of Crop and Pest Services

Glyphosate and Triclopyr Glyphosate and Triclopyr Herbicides: Herbicides:

Regulatory Review of Human Regulatory Review of Human Health and Ecological Effects Health and Ecological Effects

Hotze Wijnja, Ph.DHotze Wijnja, Ph.D..

Division of Crop and Pest ServicesDivision of Crop and Pest Services

Massachusetts Department of Agricultural Massachusetts Department of Agricultural ResourcesResources

Pesticide-Safety Workshop

OutlineOutline

Review of Pesticides for RegistrationReview of Pesticides for Registration Federal level: EPA Pesticide ProgramFederal level: EPA Pesticide Program State Level: State Level:

Registration by Pesticide Board SubcommitteeRegistration by Pesticide Board Subcommittee Special Reviews for Rights of Way and Aquatic herbicides Special Reviews for Rights of Way and Aquatic herbicides

Glyphosate and TriclopyrGlyphosate and Triclopyr Human Health and Ecological EffectsHuman Health and Ecological Effects Risk assessment by US Forest ServiceRisk assessment by US Forest Service Risk assessment for use on Cape Cod Risk assessment for use on Cape Cod

Levels of Review for Registration Levels of Review for Registration of Pesticidesof Pesticides

1.1. At the federal level by US EPAAt the federal level by US EPA

2.2. At the state level by Pesticide Board At the state level by Pesticide Board Subcommittee Subcommittee

3.3. Special reviews for specific uses: Special reviews for specific uses: Joint review with MassDEP for Joint review with MassDEP for herbicideherbicide use in use in

Rights-of-Way Rights-of-Way

Lakes and PondsLakes and Ponds

1. EPA Regulates Pesticides 1. EPA Regulates Pesticides Under Authority From:Under Authority From:

Federal Insecticide, Fungicide, and Rodenticide Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Act (FIFRA) Requires registration of all pesticides by EPA Requires registration of all pesticides by EPA

Federal Food, Drug and Cosmetic Act (FFDCA)Federal Food, Drug and Cosmetic Act (FFDCA) Requires EPA to set pesticide tolerances for all Requires EPA to set pesticide tolerances for all

pesticides used in or on foodpesticides used in or on food

Food Quality Protection Act (FQPA)Food Quality Protection Act (FQPA) Amended both FIFRA and FFDCAAmended both FIFRA and FFDCA

EPA Regulatory Authority for EPA Regulatory Authority for Pesticides Pesticides

EPA must find that a pesticides poses a EPA must find that a pesticides poses a ""reasonable certainty of no harmreasonable certainty of no harm" before that " before that pesticide can be registered for use on food/feed.pesticide can be registered for use on food/feed.

Analysis of aggregate exposure, cumulative Analysis of aggregate exposure, cumulative effects, sensitive populations (infants), and effects, sensitive populations (infants), and endocrine-disrupting effectsendocrine-disrupting effects

EPA Registration ProgramEPA Registration Program

EvaluationEvaluation of new and existing pesticides of new and existing pesticides

RegistrationRegistration of products for pest control of products for pest control

EnsureEnsure protection of human health and the protection of human health and the environmentenvironment

Registration permits the distribution, sale, Registration permits the distribution, sale, and use according to specific use directions and use according to specific use directions and requirements on the product labeland requirements on the product label A product label is A product label is a legal documenta legal document

Evaluation for RegistrationEvaluation for Registration

Human health riskHuman health risk Short-term acute effectsShort-term acute effects Long-term effects such as cancer and reproductive Long-term effects such as cancer and reproductive Aggregate exposure (food, water and residential)Aggregate exposure (food, water and residential) Cumulative risks (includes other pesticides)Cumulative risks (includes other pesticides) Occupational risksOccupational risks

Effects on wildlife, fish and plantsEffects on wildlife, fish and plants Acute and chronicAcute and chronic Including endangered speciesIncluding endangered species

Evaluation for RegistrationEvaluation for Registration

Human Health RiskHuman Health Risk Short-term acute effectsShort-term acute effects Long-term effects such as cancer and reproductive Long-term effects such as cancer and reproductive Aggregate exposure (food, water and residential)Aggregate exposure (food, water and residential) Cumulative risks (includes other pesticides)Cumulative risks (includes other pesticides) Occupational risksOccupational risks

Effects on wildlife, fish and plantsEffects on wildlife, fish and plants Acute and chronicAcute and chronic Including endangered speciesIncluding endangered species

EPA Risk AssessmentEPA Risk Assessment

Four-step process assessment: Four-step process assessment:

Step One: Hazard Identification: Hazard Identification How toxic is the substance?How toxic is the substance?

Step Two: Dose-Response Assessment: Dose-Response Assessment "The dose makes the poison.“"The dose makes the poison.“

Step Three: Exposure Assessment: Exposure Assessment Dietary, residential, recreational, occupationalDietary, residential, recreational, occupational

Step Four: Risk Characterization: Risk Characterization RISK = TOXICITY x EXPOSURERISK = TOXICITY x EXPOSURE

Risk Cup ConceptRisk Cup Concept

Each use Each use of a pesticide contributes a specific of a pesticide contributes a specific amount of exposure (risk) to humans. amount of exposure (risk) to humans.

This is compared to the This is compared to the acceptable amount of acceptable amount of risk risk (risk cup) which can not be exceeded. (risk cup) which can not be exceeded.

Risk Management and Risk Management and Regulatory DecisionsRegulatory Decisions

Consideration of risk assessment and peer reviewConsideration of risk assessment and peer review

Consideration of risk mitigation measuresConsideration of risk mitigation measures General Use or Restricted UseGeneral Use or Restricted Use

Consideration of existing alternative pesticides Consideration of existing alternative pesticides

Coordination of risk management with registrantsCoordination of risk management with registrants

Label Review and ApprovalLabel Review and Approval

Review of Registered PesticidesReview of Registered Pesticides

Programs for re-evaluation of registered Programs for re-evaluation of registered pesticides pesticides Ensure adherence to the highest standards for Ensure adherence to the highest standards for

protection of human health and the environmentprotection of human health and the environment

Registration reviewRegistration review Re-evaluation on a regular cycleRe-evaluation on a regular cycle

Special reviewSpecial review Initiated when unreasonable adverse effects occurInitiated when unreasonable adverse effects occur

2. Pesticide Regulation at the 2. Pesticide Regulation at the State LevelState Level

MDAR is responsible for regulating the use of MDAR is responsible for regulating the use of pesticides in Massachusettspesticides in Massachusetts Registration of pesticidesRegistration of pesticides Licensing and certification of applicatorsLicensing and certification of applicators Enforcing federal and state laws and regulationsEnforcing federal and state laws and regulations

Pesticide Program ObjectivesPesticide Program Objectives Regulate the use of pesticidesRegulate the use of pesticides Protect human health and the environment Protect human health and the environment

Pesticide Board SubcommitteePesticide Board Subcommittee

Registration of Pesticides in MARegistration of Pesticides in MA

Five members from the Pesticide BoardFive members from the Pesticide Board

Director of Food Protection Program, MDPH – Director of Food Protection Program, MDPH –

ChairpersonChairperson

Commissioner of MDAR or designeeCommissioner of MDAR or designee

Commissioner of MDPH or designeeCommissioner of MDPH or designee

Commissioner of MDCR or designeeCommissioner of MDCR or designee

Commercial ApplicatorCommercial Applicator

Subcommittee Registration Subcommittee Registration ClassificationClassification

Subcommittee determines potential to Subcommittee determines potential to cause unreasonable adverse effects when cause unreasonable adverse effects when used as labeledused as labeled

Classification of RegistrationClassification of Registration Not to registerNot to register

Register – unclassified/ Register – unclassified/ General UseGeneral Use

Register and classify for Register and classify for Restricted Use Restricted Use (e.g. (e.g.

classification as a classification as a potential groundwater contaminantpotential groundwater contaminant))

Register for Special Local NeedRegister for Special Local Need

Registration ClassificationRegistration Classification

Classification as State Restricted Use Pesticide Classification as State Restricted Use Pesticide based on:based on:

Potential for groundwater contaminationPotential for groundwater contamination

Subsurface termiticide useSubsurface termiticide use

Toxicity concernsToxicity concerns

Other Subcommittee concernsOther Subcommittee concernsFor example, toxicity to specific non-targets such as For example, toxicity to specific non-targets such as honey bees honey bees

Groundwater Protection ListGroundwater Protection List

April 3, 2009 CCCGA Winter Meeting

3. Special Review for Rights-of-Way 3. Special Review for Rights-of-Way and Aquatic Herbicides in MAand Aquatic Herbicides in MA

Specific Regulations for Specific Regulations for

Rights-of-Way managementRights-of-Way management Sensitive Area Materials ListSensitive Area Materials List

Aquatic Herbicides: Aquatic Herbicides: Licensed use of approved herbicides (those included Licensed use of approved herbicides (those included

in GEIR)in GEIR)

Special review process for herbicides to be Special review process for herbicides to be approved for rights-of-way and aquatic useapproved for rights-of-way and aquatic use

Special Review ProcessSpecial Review Process

Cooperative review by MDAR and MassDEPCooperative review by MDAR and MassDEP

Scientific review of herbicide products includes:Scientific review of herbicide products includes: Physical and chemical characteristicsPhysical and chemical characteristics EPA registration standard and statusEPA registration standard and status Primary and secondary data sourcesPrimary and secondary data sources If necessary, additional data will be requested from If necessary, additional data will be requested from

registrantregistrant Review addresses both Review addresses both active ingredients active ingredients and “and “otherother” ”

or “or “inertinert” ingredients” ingredients

Rights-of-Way Management Rights-of-Way Management Regulations (333 CMR 11.00)Regulations (333 CMR 11.00)

Provide provisions for sensitive areas within Provide provisions for sensitive areas within rights-of-wayrights-of-way

Sensitive area restrictions include:Sensitive area restrictions include: Only herbicides listed on the “Sensitive Area Materials Only herbicides listed on the “Sensitive Area Materials

List” shall be usedList” shall be used

Criteria and procedures for review of herbicides Criteria and procedures for review of herbicides for use within sensitive areas are established in for use within sensitive areas are established in a Cooperative Agreement between MDAR and a Cooperative Agreement between MDAR and MassDEP (1987)MassDEP (1987)

Sensitive Area Materials ListSensitive Area Materials List

Herbicides specified to be acceptable for use in Herbicides specified to be acceptable for use in sensitive areassensitive areas

Currently Listed Active Ingredients:Currently Listed Active Ingredients: GlyphosateGlyphosate Metsulfuron-methylMetsulfuron-methyl Sulfometuron-methylSulfometuron-methyl FosamineFosamine ImazapyrImazapyr TriclopyrTriclopyr

Protocol for Active IngredientsProtocol for Active Ingredients

Environmental fate and transport characteristicsEnvironmental fate and transport characteristics TransportTransport

Water solubilityWater solubility Partitioning characteristics Partitioning characteristics Vapor pressure (volatility)Vapor pressure (volatility) Speciation at ambient pHSpeciation at ambient pH

PersistencePersistence Hydrolysis half-lifeHydrolysis half-life Photolysis half-lifePhotolysis half-life Soil half-lifeSoil half-life

Environmental Fate EvaluationEnvironmental Fate Evaluation

Supported by computer modeling by using EPA-Supported by computer modeling by using EPA-approved models for environmental exposure approved models for environmental exposure assessments. assessments.

Models generate predicted environmental Models generate predicted environmental concentrations in soil and water for situations concentrations in soil and water for situations specified with the input parameters, includingspecified with the input parameters, including Chemical propertiesChemical properties Application characteristicsApplication characteristics Soil and meteorological inputSoil and meteorological input

Toxicity CriteriaToxicity Criteria

Mammalian toxicityMammalian toxicity

Acute: LD50 values; Irritant effectsAcute: LD50 values; Irritant effects

Chronic/ SubchronicChronic/ Subchronic

No Observed Adverse Effect Levels (NOAEL)No Observed Adverse Effect Levels (NOAEL)

Lowest Observed Adverse Effect Levels (LOAEL)Lowest Observed Adverse Effect Levels (LOAEL)

Reproductive and developmental toxicityReproductive and developmental toxicity

CarcinogenicityCarcinogenicity

MutagenicityMutagenicity

Aquatic Life Toxicity CriteriaAquatic Life Toxicity Criteria

Acute (fish and invertebrates)Acute (fish and invertebrates)

Lethal Concentration (LC50) valuesLethal Concentration (LC50) values

Chronic/SubchronicChronic/Subchronic

No Observed Effect Concentration No Observed Effect Concentration

Lowest Observed Effect ConcentrationLowest Observed Effect Concentration


AvianToxicity CriteriaAvianToxicity Criteria

AcuteAcute

Lethal Dose (LD50) valuesLethal Dose (LD50) values





Amphibian Toxicity CriteriaAmphibian Toxicity Criteria

AcuteAcute

Lethal Dose (LD50) valuesLethal Dose (LD50) values





Risk CharacterizationRisk Characterization

Based on comparison of predicted Based on comparison of predicted environmental concentrations with:environmental concentrations with: “ “No Observed Effect Levels” or “Lowest Observed No Observed Effect Levels” or “Lowest Observed

Effect Levels” Effect Levels” LC50 values LC50 values

Hazard Index (HI), or Hazard Index (HI), or Risk Quotient (RQ)Risk Quotient (RQ)

Comparison of HI or RQ with Levels of Concern Comparison of HI or RQ with Levels of Concern established for various classes of organismsestablished for various classes of organisms

Sensitive Area Materials ListSensitive Area Materials List

Examples of Active ingredients and approved products

Review Criteria for “Other” IngredientsReview Criteria for “Other” Ingredients

Surfactants and detergents are a common Surfactants and detergents are a common component of herbicide formulationscomponent of herbicide formulations

Concerns for potential effects on aquatic Concerns for potential effects on aquatic organismsorganisms

Review protocol similar to active ingredient Review protocol similar to active ingredient protocol protocol Environmental fate and toxicological information will Environmental fate and toxicological information will

be consideredbe considered Supplemental information may be obtained through Supplemental information may be obtained through

use predictive tools approved by EPAuse predictive tools approved by EPA

List of Approved SurfactantsList of Approved Surfactants

Recently completed a risk assessment of Recently completed a risk assessment of commonly used surfactants in herbicide commonly used surfactants in herbicide productsproducts

Resulted in a list of approved surfactants for use Resulted in a list of approved surfactants for use in Sensitive Areas of Rights-of-Wayin Sensitive Areas of Rights-of-Way

New requests for herbicide products containing New requests for herbicide products containing surfactants that are not listed will have to surfactants that are not listed will have to undergo a review following the same criteriaundergo a review following the same criteria

List of Approved SurfactantsList of Approved Surfactants

Polyethoxylated ethylamines (POEA)Polyethoxylated ethylamines (POEA) Alkylphenol ethoxylates (APE)Alkylphenol ethoxylates (APE) Alcohol ethoxylates (AE)Alcohol ethoxylates (AE) Phosphate ester ethoxylates (PE)Phosphate ester ethoxylates (PE) Organosilicones (OS)Organosilicones (OS)

The need for re-evalution will be considered The need for re-evalution will be considered when new data become availablewhen new data become available

Herbicide Reviews for ROWHerbicide Reviews for ROW

Active Ingredient &

Product

• Fate & transport

• Toxicological characterizations – humans, non-target organisms

• Use & application characteristics (e.g., Limited and No-Spray Zone; Application Rate and Frequency)

• Exposure assessments & risk characterization

Approved Not Approved

Apply use restrictions

Still unacceptableAcceptable

Surfactants & other

adjuvants

Components of Herbicide Review Process for Sensitive Areas of Rights-of-Way

DEQE/DFA Cooperative Agreement Relative to Section 4(1) (E) of 333 CMR 11.00 Rights-of-Way Management

Regulations. July 1987

Legislation: 333 CMR 11.00 Rights-of-Way Management Regulations

Statement of Policy on Restricting the Use of Surfactants as Part of the Evaluation Process for Herbicides Proposed for Use in Sensitive Areas of

Rights-of-Way. March 1989

HERBICIDE EVALUATION TECHNICAL UPDATE No. 2

List of Approved Surfactants for Use in Sensitive Areas of Rights-of-Way – June 2010

HERBICIDE EVALUATION TECHNICAL UPDATE No. 1

Methods for the Evaluation of Herbicides for Use in

Sensitive Areas of Rights-of-WayJune 2010

Surfactant Ecological Risk Assessment

(Wijnja, 2010)

Reference: Wijnja, H. 2010. Ecological Risk Assessment of Surfactants Associated with Herbicide Application in Rights-of-Way Areas.

Massachusetts Department of Agricultural Resources. Boston, MA

Ver 2.0February 2011

Summary of Regulatory ReviewSummary of Regulatory Review

These levels of review and evaluation for These levels of review and evaluation for registration and addition to the Sensitive Area registration and addition to the Sensitive Area Materials List and the rigorous regulatory Materials List and the rigorous regulatory process for rights-of-way are in place to ensure:process for rights-of-way are in place to ensure:

Protection from potential impacts on human Protection from potential impacts on human health and the environment from the selective health and the environment from the selective use of these herbicidesuse of these herbicides

Allow the benefits of selective use of herbicides Allow the benefits of selective use of herbicides to maintain rights-of-wayto maintain rights-of-way

GlyphosateGlyphosate

First registered by EPA in 1974First registered by EPA in 1974 Widely used non-selective herbicidesWidely used non-selective herbicides Mode of Action: Inhibition of plant enzymeMode of Action: Inhibition of plant enzyme

Acute Toxicity Acute Toxicity (mammalian)(mammalian) Low by oral exposure (LDLow by oral exposure (LD5050 >4320 mg/kg (rat) >4320 mg/kg (rat) Low by dermal exposure (skin, eye) (2 g/kg)Low by dermal exposure (skin, eye) (2 g/kg) Not a skin sensitizerNot a skin sensitizer Very low by inhalation (4.43 mg/L)Very low by inhalation (4.43 mg/L) Product formulations may cause irritation due to other Product formulations may cause irritation due to other

ingredientsingredients

Glyphosate: Chronic Toxicity Glyphosate: Chronic Toxicity

Dog study 1(yr): No effects; NOEL > 500 Dog study 1(yr): No effects; NOEL > 500 mg/kg/d mg/kg/d

Rat (2 yr): decreased body weight, effects on Rat (2 yr): decreased body weight, effects on eyes and liver at high doses (NOEL = 362 eyes and liver at high doses (NOEL = 362 mg/kg/dmg/kg/d

Reproductive and Developmental Effects:Reproductive and Developmental Effects: No link to effects in rats except at very high doses No link to effects in rats except at very high doses Fetuses gained weight more slowly Fetuses gained weight more slowly Some fetuses had skelatal abnormalitiesSome fetuses had skelatal abnormalities No reproductive effects by glyphosate, AMPA, POEANo reproductive effects by glyphosate, AMPA, POEA

Glyphosate: Chronic EffectsGlyphosate: Chronic Effects

Carcinogenicity:Carcinogenicity: Animal studies have not shown evidence that Animal studies have not shown evidence that

exposure to glyphosate is linked to cancerexposure to glyphosate is linked to cancer Classified as “Evidence of non-carcinogenicity in Classified as “Evidence of non-carcinogenicity in

humans”humans”

Endocrine Disruption: no evidence of effectsEndocrine Disruption: no evidence of effects

Fate in the Human Body: Fate in the Human Body: Any glyphosate taken in through skin or mouth goes Any glyphosate taken in through skin or mouth goes

through the body in less than a daythrough the body in less than a day

Glyphosate: Environmental FateGlyphosate: Environmental Fate

In soilIn soil: break down by microbes to several : break down by microbes to several smaller compounds, ultimately to COsmaller compounds, ultimately to CO22, water and , water and

saltssalts Typical field half-life ranges is about 47 d Typical field half-life ranges is about 47 d Binds strongly to soil, immobile in soilBinds strongly to soil, immobile in soil

In waterIn water: microbial break down : microbial break down Half-life: few days to 90 daysHalf-life: few days to 90 days

No significant exposure to air expected (very low No significant exposure to air expected (very low volatility)volatility)

Glyphosate: EcotoxicityGlyphosate: Ecotoxicity

Birds: Practically non-toxic (LDBirds: Practically non-toxic (LD5050 >200 mg/kg) >200 mg/kg)

Fish: slightly to practically non-toxic (LCFish: slightly to practically non-toxic (LC5050 24-140 24-140

mg/L); products: 1.3 – 1000 mg/L mg/L); products: 1.3 – 1000 mg/L

Aquatic Invertebrates: Slightly to practically non-toxic Aquatic Invertebrates: Slightly to practically non-toxic (LC (LC5050 55-780 mg/L; products: 3-16 mg/L) 55-780 mg/L; products: 3-16 mg/L)

Amphibians: Moderately to slightly toxic to product Amphibians: Moderately to slightly toxic to product formulations (LCformulations (LC5050 6.6-18.1 mg/L) 6.6-18.1 mg/L)

Honey bees: practically non-toxic Honey bees: practically non-toxic

Earthworm: practically non-toxicEarthworm: practically non-toxic

TriclopyrTriclopyr

First registered by EPA in 1979First registered by EPA in 1979

Selective herbicide used to control woody and Selective herbicide used to control woody and herbaceous weeds in non-crop areasherbaceous weeds in non-crop areas

Two common forms: Two common forms: Triethylamine (TEA) Triethylamine (TEA) Butoxyethyl ester (BEE)Butoxyethyl ester (BEE)

Mode of Action: Mimics the effects of plant Mode of Action: Mimics the effects of plant hormones (auxins)hormones (auxins)

TriclopyrTriclopyr

Acute Toxicity (mammalian)Acute Toxicity (mammalian) Low by oral exposure (LDLow by oral exposure (LD5050 830-1847 mg/kg (rat)) 830-1847 mg/kg (rat)) Mildly irritating to corrosive to the eyesMildly irritating to corrosive to the eyes Non-irritating to the skin of rabbits; skin sensitizer on Non-irritating to the skin of rabbits; skin sensitizer on

guinea pigsguinea pigs Low toxicity by inhalation Low toxicity by inhalation

Fate in body:Fate in body: Low rate of absorption Low rate of absorption Rapidly eliminatedRapidly eliminated

Triclopyr: Chronic EffectsTriclopyr: Chronic Effects

Rat study (13 weeks); Rat study (13 weeks); Effects on kidneys and liver at 20 mg/kgEffects on kidneys and liver at 20 mg/kg

Dog study: (183- 228 d) Dog study: (183- 228 d) Effects on body weight, food consumption, blood Effects on body weight, food consumption, blood

chemistry, liver and kidneys at 20 mg/kg. chemistry, liver and kidneys at 20 mg/kg. No effects at lower at 2.5 and 5.0 mg/kg dosesNo effects at lower at 2.5 and 5.0 mg/kg doses

Fate in body: Elimination with 2 – 3 daysFate in body: Elimination with 2 – 3 days

Triclopyr: Chronic Triclopyr: Chronic

Carcinogenicity Carcinogenicity No tumors in male rats and mice (2 yr study)No tumors in male rats and mice (2 yr study) Increase of number of tumors in female rats and mice Increase of number of tumors in female rats and mice Classified as: “Not classifiable as to human Classified as: “Not classifiable as to human

carcinogenicity”carcinogenicity”

Reproductive and Developmental EffectsReproductive and Developmental Effects Rat and rabbit studies show low potential for effectsRat and rabbit studies show low potential for effects At high levels, decrease in live fetuses and skelatal At high levels, decrease in live fetuses and skelatal

effects effects

Triclopyr: Environmental FateTriclopyr: Environmental Fate

In soilIn soil: breaks down to several smaller : breaks down to several smaller compounds, ultimately to COcompounds, ultimately to CO22, water and salts, water and salts Half-life ranges from 1.1 to 90 days Half-life ranges from 1.1 to 90 days Mobile in soilMobile in soil

In waterIn water, breaks down by exposure to sunlight, breaks down by exposure to sunlight Half-life is 1-10 daysHalf-life is 1-10 days

No significant exposure to air expected (low No significant exposure to air expected (low volatility)volatility)

Triclopyr: EcotoxicityTriclopyr: Ecotoxicity

Birds: Practically non-toxic (LDBirds: Practically non-toxic (LD5050 >735 mg/kg) >735 mg/kg)

Fish: Fish: TEA: practically non-toxic LCTEA: practically non-toxic LC5050 >100 mg/L); >100 mg/L);

BEE: moderately to highly toxic (LCBEE: moderately to highly toxic (LC5050 0.1 - 10 mg/L ) 0.1 - 10 mg/L )

Aquatic Invertebrates: Aquatic Invertebrates: TEA: practically non-toxic (LCTEA: practically non-toxic (LC5050 1496 mg/L) 1496 mg/L)

BEE: moderately toxic (LCBEE: moderately toxic (LC5050 1.7-12 mg/L) 1.7-12 mg/L)

Honey bees: practically non-toxic Honey bees: practically non-toxic

USDA Forest Service USDA Forest Service Risk Assessments Risk Assessments

Use PatternUse Pattern Conifer release, site preparation, noxious weed Conifer release, site preparation, noxious weed

control, and rights-of-way managementcontrol, and rights-of-way management

GlyphosateGlyphosate Human Health Assessment:Human Health Assessment:

Low mammalian toxicity, very few specifics can be Low mammalian toxicity, very few specifics can be identifiedidentified

Developmental effects are most sensitive endpointDevelopmental effects are most sensitive endpoint Formulations vary around the world; some studies from Formulations vary around the world; some studies from

South America suggest potential endocrine and genotoxic South America suggest potential endocrine and genotoxic effectseffects

Forest Service Risk AssessmentForest Service Risk Assessment Risk characterization: Hazard Quotient (HQ)Risk characterization: Hazard Quotient (HQ)

HQ = Estimated Dose/ Reference DoseHQ = Estimated Dose/ Reference Dose Level of concern HQ > 1Level of concern HQ > 1

Workers: minimal concernWorkers: minimal concern General public: only concern for exposure by General public: only concern for exposure by

consuming vegetation consuming vegetation shortly after treatmentshortly after treatment

EcologicalEcological LOC exceeded for Aquatic organisms for product LOC exceeded for Aquatic organisms for product

formulations with POEA; formulations with POEA; Care should be taken with the use of such formulations near Care should be taken with the use of such formulations near

water bodieswater bodies

Forest Service Risk AssessmentForest Service Risk Assessment

TriclopyrTriclopyr Level of Concern exceeded for:Level of Concern exceeded for:

Workers based on worst-case scenariosWorkers based on worst-case scenarios General public: only concern for exposure by General public: only concern for exposure by

consuming vegetation shortly after treatmentconsuming vegetation shortly after treatment

Ecological:Ecological: Level of Concern exceeded for large mammals and Level of Concern exceeded for large mammals and

birds consuming contaminated vegetationbirds consuming contaminated vegetation Sensitive non-target plants can be affected Sensitive non-target plants can be affected

MDAR Herbicide Assessment MDAR Herbicide Assessment on Cape Codon Cape Cod

ObjectivesObjectives::

Evaluate the fate of herbicides used in utility Evaluate the fate of herbicides used in utility rights-of-way in common soil on Cape Codrights-of-way in common soil on Cape Cod

Evaluate the effects on groundwater and surface Evaluate the effects on groundwater and surface water for: water for: Human health Human health Ecological (aquatic life) effectsEcological (aquatic life) effects

Modeling of Pesticide Fate Modeling of Pesticide Fate in Soilsin Soils

Fate in soil was simulated by EPA’s Pesticide Fate in soil was simulated by EPA’s Pesticide Root Zone Model (PRZM) Root Zone Model (PRZM)

Input parameters include:Input parameters include: Application rate, chemical and Application rate, chemical and

environmental fate properties, soil and environmental fate properties, soil and vegetation characteristics, meteorological vegetation characteristics, meteorological data data

Output includes:Output includes: Herbicide concentration profile in soil Herbicide concentration profile in soil

Groundwater EvaluationGroundwater Evaluation

• Exposure of herbicides to groundwater was Exposure of herbicides to groundwater was simulated with SCI-GROW modelsimulated with SCI-GROW model

• EPA-approved generic screening level modelEPA-approved generic screening level model• Simulates high-end estimates for groundwater Simulates high-end estimates for groundwater

concentration levelsconcentration levels

• Simulates behavior on a vulnerable site:Simulates behavior on a vulnerable site:– Sandy soils Sandy soils – Low organic content (<1%) Low organic content (<1%) – Shallow groundwater (avg. 14 ft)Shallow groundwater (avg. 14 ft)

Simulated Groundwater ConcentrationsSimulated Groundwater Concentrations

Herbicide Simulated Concentration

(parts-per-billion, ppb)

Health-Based Standard1 or Health Value2 (ppb)

Imazapyr 1.46 20000

Glyphosate 0.0066 700

Fosamine 0.147 350

Metsulfuron-methyl

0. 027 8750

Triclopyr 0.713 17501 Health-based standards represent concentrations at which a lifetime of exposure does not result in adverse effect to human health; 2 Health value calculated based on RfD value.

Comparison with Health-Based Comparison with Health-Based StandardsStandards

13,700 xlower

106,060 xlower

2,380 xlower

324,000 xlower 2450 x

lower

Note the Y-axis is expressed on a log-based scale!!

Glyphosate

Surface Water EvaluationSurface Water Evaluation

• Exposure of herbicides to surface water was Exposure of herbicides to surface water was simulated with PRZM-EXAMSsimulated with PRZM-EXAMS

• The field-scale runoff/leaching model that simulates:The field-scale runoff/leaching model that simulates:– Runoff, erosion, plant uptake, leaching, decay, foliar wash Runoff, erosion, plant uptake, leaching, decay, foliar wash

off, and volatilization; selected value for off-site driftoff, and volatilization; selected value for off-site drift– Input includes soil, vegetation and local climate dataInput includes soil, vegetation and local climate data– Does not consider buffer zoneDoes not consider buffer zone

• Output includes simulated herbicide concentrations Output includes simulated herbicide concentrations at various time intervals:at various time intervals:– From initial peak concentration up to 90 day-concentration From initial peak concentration up to 90 day-concentration

Simulated Surface Water Simulated Surface Water ConcentrationsConcentrations

Herbicide

Simulated Concentration

(parts-per-billion, ppb)

Ecological Benchmark1 or

Toxicological Endpoint2 (ppb)

(Fish, acute effects)

Imazapyr 0.86 >50,0001

Glyphosate 0.73 21,5001

Fosamine-ammonium

1.5 >150,0002

Metsulfuron-methyl

0.006 670,0002

Comparison with Aquatic Life Comparison with Aquatic Life Benchmarks Acute EffectsBenchmarks Acute Effects

Fish Invertebrates80

0 x

low

er

29,0

00 x

low

er

3500

xlo

wer

36,0

00 x

low

er

ConclusionsConclusions

ROW herbicide are applied at relatively low ratesROW herbicide are applied at relatively low rates

Simulated concentrations in ground- and surface Simulated concentrations in ground- and surface

water are well below health-based and water are well below health-based and ecological standardsecological standards

These low exposure levels indicate minimal risk These low exposure levels indicate minimal risk to human health and non-target organismsto human health and non-target organisms

Further Reduction of ExposureFurther Reduction of Exposure

Simulations represent worst-case scenario or Simulations represent worst-case scenario or high-end of exposure potentialhigh-end of exposure potential

Exposure is reduced by limited-spray zones and Exposure is reduced by limited-spray zones and no-spray zonesno-spray zones

No-spray zones include:No-spray zones include: 50 ft from private well50 ft from private well 10 ft from surface water or wetland 10 ft from surface water or wetland

SummarySummary

Herbicides for vegetation in rights-of-way, aquatic Herbicides for vegetation in rights-of-way, aquatic systems and similar areas undergo rigorous systems and similar areas undergo rigorous regulatory review regulatory review

Properties and effects have been well characterizedProperties and effects have been well characterized Conservative risk assessments indicate low risks for Conservative risk assessments indicate low risks for

humans and non-target organisms, except plantshumans and non-target organisms, except plants Following all applicable regulations and label Following all applicable regulations and label

instructions should provide sufficient protection instructions should provide sufficient protection while allowing herbicides as effective tools while allowing herbicides as effective tools

Hotze WijnjaHotze Wijnja,, Ph.D. Ph.D.

Environmental ChemistEnvironmental ChemistMassachusetts Department of Agricultural Massachusetts Department of Agricultural

ResourcesResourcesPhone: 617-626-1771Phone: 617-626-1771

[email protected]@state.ma.uswww.Mass.gov/AGRwww.Mass.gov/AGR

ResourcesResources

MDAR, Division of Crop and Pest ServicesMDAR, Division of Crop and Pest Services http://www.mass.gov/agr/divisions/http://www.mass.gov/agr/divisions/

crop_inspec_services_pest_services.htmcrop_inspec_services_pest_services.htm

EPA Office of Pesticide ProgramsEPA Office of Pesticide Programs http://www.epa.gov/pesticides/index.htmhttp://www.epa.gov/pesticides/index.htm

National Pesticide Information Center (NPIC)National Pesticide Information Center (NPIC) http://npic.orst.edu/ and 1.800.858.7378http://npic.orst.edu/ and 1.800.858.7378

USDA Forest ServiceUSDA Forest Service http://www.fs.fed.us/foresthealth/pesticide/risk.shtmlhttp://www.fs.fed.us/foresthealth/pesticide/risk.shtml

Documents

Hotze Wijnja, Ph.D . Division of Crop and Pest Services