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Glyphosate and Triclopyr Herbicides: Regulatory Review of Human Health and Ecological Effects Glyphosate and Triclopyr Herbicides: Regulatory Review of.

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1 Glyphosate and Triclopyr Herbicides: Regulatory Review of Human Health and Ecological Effects Glyphosate and Triclopyr Herbicides: Regulatory Review of Human Health and Ecological Effects Hotze Wijnja, Ph.D. Division of Crop and Pest Services Massachusetts Department of Agricultural Resources Pesticide-Safety Workshop

2 Outline Review of Pesticides for Registration Review of Pesticides for Registration Federal level: EPA Pesticide Program Federal level: EPA Pesticide Program State Level: State Level: Registration by Pesticide Board Subcommittee Registration by Pesticide Board Subcommittee Special Reviews for Rights of Way and Aquatic herbicides Special Reviews for Rights of Way and Aquatic herbicides Glyphosate and Triclopyr Glyphosate and Triclopyr Human Health and Ecological Effects Human Health and Ecological Effects Risk assessment by US Forest Service Risk assessment by US Forest Service Risk assessment for use on Cape Cod Risk assessment for use on Cape Cod

3 Levels of Review for Registration of Pesticides 1.At the federal level by US EPA 2.At the state level by Pesticide Board Subcommittee 3.Special reviews for specific uses: Joint review with MassDEP for herbicide use in Rights-of-Way Rights-of-Way Lakes and Ponds Lakes and Ponds

4 1. EPA Regulates Pesticides Under Authority From: Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Federal Insecticide, Fungicide, and Rodenticide 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 pesticides used in or on food Requires EPA to set pesticide tolerances for all pesticides used in or on food Food Quality Protection Act (FQPA) Food Quality Protection Act (FQPA) Amended both FIFRA and FFDCA Amended both FIFRA and FFDCA

5 EPA Regulatory Authority for Pesticides EPA must find that a pesticides poses a "reasonable certainty of no harm" before that pesticide can be registered for use on food/feed. EPA must find that a pesticides poses a "reasonable certainty of no harm" before that pesticide can be registered for use on food/feed. Analysis of aggregate exposure, cumulative effects, sensitive populations (infants), and endocrine-disrupting effects Analysis of aggregate exposure, cumulative effects, sensitive populations (infants), and endocrine-disrupting effects

6 EPA Registration Program Evaluation of new and existing pesticides Evaluation of new and existing pesticides Registration of products for pest control Registration of products for pest control Ensure protection of human health and the environment Ensure protection of human health and the environment Registration permits the distribution, sale, and use according to specific use directions and requirements on the product label Registration permits the distribution, sale, and use according to specific use directions and requirements on the product label A product label is a legal document A product label is a legal document

7 Evaluation for Registration Human health risk Human health risk Short-term acute effects Short-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 risks Occupational risks Effects on wildlife, fish and plants Effects on wildlife, fish and plants Acute and chronic Acute and chronic Including endangered species Including endangered species

8 Evaluation for Registration Human Health Risk Human Health Risk Short-term acute effects Short-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 risks Occupational risks Effects on wildlife, fish and plants Effects on wildlife, fish and plants Acute and chronic Acute and chronic Including endangered species Including endangered species

9 EPA Risk Assessment Four-step process assessment: Step One: Hazard Identification Step One: Hazard Identification Step One Step One How toxic is the substance? How toxic is the substance? Step Two: Dose-Response Assessment Step Two: Dose-Response Assessment Step Two Step Two "The dose makes the poison.“ "The dose makes the poison.“ Step Three: Exposure Assessment Step Three: Exposure Assessment Step Three Step Three Dietary, residential, recreational, occupational Dietary, residential, recreational, occupational Step Four: Risk Characterization Step Four: Risk Characterization Step Four Step Four RISK = TOXICITY x EXPOSURE RISK = TOXICITY x EXPOSURE

10 Risk Cup Concept Each use of a pesticide contributes a specific amount of exposure (risk) to humans. Each use of a pesticide contributes a specific amount of exposure (risk) to humans. This is compared to the acceptable amount of risk (risk cup) which can not be exceeded. This is compared to the acceptable amount of risk (risk cup) which can not be exceeded.

11 Risk Management and Regulatory Decisions Consideration of risk assessment and peer review Consideration of risk assessment and peer review Consideration of risk mitigation measures Consideration of risk mitigation measures General Use or Restricted Use General Use or Restricted Use Consideration of existing alternative pesticides Consideration of existing alternative pesticides Coordination of risk management with registrants Coordination of risk management with registrants Label Review and Approval Label Review and Approval

12 Review of Registered Pesticides Programs for re-evaluation of registered pesticides Programs for re-evaluation of registered pesticides Ensure adherence to the highest standards for protection of human health and the environment Ensure adherence to the highest standards for protection of human health and the environment Registration review Registration review Re-evaluation on a regular cycle Re-evaluation on a regular cycle Special review Special review Initiated when unreasonable adverse effects occur Initiated when unreasonable adverse effects occur

13 2. Pesticide Regulation at the State Level MDAR is responsible for regulating the use of pesticides in Massachusetts MDAR is responsible for regulating the use of pesticides in Massachusetts Registration of pesticides Registration of pesticides Licensing and certification of applicators Licensing and certification of applicators Enforcing federal and state laws and regulations Enforcing federal and state laws and regulations Pesticide Program Objectives Pesticide Program Objectives Regulate the use of pesticides Regulate the use of pesticides Protect human health and the environment Protect human health and the environment

14 Pesticide Board Subcommittee Registration of Pesticides in MA Registration of Pesticides in MA Five members from the Pesticide Board Five members from the Pesticide Board Director of Food Protection Program, MDPH – Chairperson Director of Food Protection Program, MDPH – Chairperson Commissioner of MDAR or designee Commissioner of MDAR or designee Commissioner of MDPH or designee Commissioner of MDPH or designee Commissioner of MDCR or designee Commissioner of MDCR or designee Commercial Applicator Commercial Applicator

15 Subcommittee Registration Classification Subcommittee determines potential to cause unreasonable adverse effects when used as labeled Subcommittee determines potential to cause unreasonable adverse effects when used as labeled Classification of Registration Classification of Registration Not to register Not to register Register – unclassified/ General Use Register – unclassified/ General Use Register and classify for Restricted Use (e.g. classification as a potential groundwater contaminant) Register and classify for Restricted Use (e.g. classification as a potential groundwater contaminant) Register for Special Local Need Register for Special Local Need

16 Registration Classification Classification as State Restricted Use Pesticide based on: Classification as State Restricted Use Pesticide based on: Potential for groundwater contamination Potential for groundwater contamination Subsurface termiticide use Subsurface termiticide use Toxicity concerns Toxicity concerns Other Subcommittee concerns Other Subcommittee concerns For example, toxicity to specific non-targets such as honey bees

17 Groundwater Protection List April 3, 2009 CCCGA Winter Meeting

18 3. Special Review for Rights-of-Way and Aquatic Herbicides in MA Specific Regulations for Specific Regulations for Rights-of-Way management Sensitive Area Materials List Sensitive Area Materials List Aquatic Herbicides: Aquatic Herbicides: Licensed use of approved herbicides (those included in GEIR) Licensed use of approved herbicides (those included in GEIR) Special review process for herbicides to be approved for rights-of-way and aquatic use Special review process for herbicides to be approved for rights-of-way and aquatic use

19 Special Review Process Cooperative review by MDAR and MassDEP Cooperative review by MDAR and MassDEP Scientific review of herbicide products includes: Scientific review of herbicide products includes: Physical and chemical characteristics Physical and chemical characteristics EPA registration standard and status EPA registration standard and status Primary and secondary data sources Primary and secondary data sources If necessary, additional data will be requested from registrant If necessary, additional data will be requested from registrant Review addresses both active ingredients and “other” or “inert” ingredients Review addresses both active ingredients and “other” or “inert” ingredients

20 Rights-of-Way Management Regulations (333 CMR 11.00) Provide provisions for sensitive areas within rights-of-way Provide provisions for sensitive areas within rights-of-way Sensitive area restrictions include: Sensitive area restrictions include: Only herbicides listed on the “Sensitive Area Materials List” shall be used Only herbicides listed on the “Sensitive Area Materials List” shall be used Criteria and procedures for review of herbicides for use within sensitive areas are established in a Cooperative Agreement between MDAR and MassDEP (1987) Criteria and procedures for review of herbicides for use within sensitive areas are established in a Cooperative Agreement between MDAR and MassDEP (1987)

21 Sensitive Area Materials List Herbicides specified to be acceptable for use in sensitive areas Herbicides specified to be acceptable for use in sensitive areas Currently Listed Active Ingredients: Currently Listed Active Ingredients: Glyphosate Glyphosate Metsulfuron-methyl Metsulfuron-methyl Sulfometuron-methyl Sulfometuron-methyl Fosamine Fosamine Imazapyr Imazapyr Triclopyr Triclopyr

22 Protocol for Active Ingredients Environmental fate and transport characteristics Environmental fate and transport characteristics Transport Transport Water solubility Water solubility Partitioning characteristics Partitioning characteristics Vapor pressure (volatility) Vapor pressure (volatility) Speciation at ambient pH Speciation at ambient pH Persistence Persistence Hydrolysis half-life Hydrolysis half-life Photolysis half-life Photolysis half-life Soil half-life Soil half-life

23 Environmental Fate Evaluation Supported by computer modeling by using EPA- approved models for environmental exposure assessments. Supported by computer modeling by using EPA- approved models for environmental exposure assessments. Models generate predicted environmental concentrations in soil and water for situations specified with the input parameters, including Models generate predicted environmental concentrations in soil and water for situations specified with the input parameters, including Chemical properties Chemical properties Application characteristics Application characteristics Soil and meteorological input Soil and meteorological input

24 Toxicity Criteria Mammalian toxicity Mammalian toxicity Acute: LD50 values; Irritant effects Acute: LD50 values; Irritant effects Chronic/ Subchronic Chronic/ 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 toxicity Reproductive and developmental toxicity Carcinogenicity Carcinogenicity Mutagenicity Mutagenicity

25 Aquatic Life Toxicity Criteria Acute (fish and invertebrates) Acute (fish and invertebrates) Lethal Concentration (LC50) values Lethal Concentration (LC50) values Chronic/Subchronic Chronic/Subchronic No Observed Effect Concentration No Observed Effect Concentration Lowest Observed Effect Concentration Lowest Observed Effect Concentration Reproductive and developmental toxicity Reproductive and developmental toxicity

26 AvianToxicity Criteria Acute Acute Lethal Dose (LD50) values Lethal Dose (LD50) values Chronic/Subchronic Chronic/Subchronic No Observed Effect Concentration No Observed Effect Concentration Lowest Observed Effect Concentration Lowest Observed Effect Concentration Reproductive and developmental toxicity Reproductive and developmental toxicity

27 Amphibian Toxicity Criteria Acute Acute Lethal Dose (LD50) values Lethal Dose (LD50) values Chronic/Subchronic Chronic/Subchronic No Observed Effect Concentration No Observed Effect Concentration Lowest Observed Effect Concentration Lowest Observed Effect Concentration Reproductive and developmental toxicity Reproductive and developmental toxicity

28 Risk Characterization Based on comparison of predicted environmental concentrations with: Based on comparison of predicted environmental concentrations with: “No Observed Effect Levels” or “Lowest Observed Effect Levels” “No Observed Effect Levels” or “Lowest Observed 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 established for various classes of organisms Comparison of HI or RQ with Levels of Concern established for various classes of organisms

29 Sensitive Area Materials List Examples of Active ingredients and approved products

30 Review Criteria for “Other” Ingredients Surfactants and detergents are a common component of herbicide formulations Surfactants and detergents are a common component of herbicide formulations Concerns for potential effects on aquatic organisms Concerns for potential effects on aquatic organisms Review protocol similar to active ingredient protocol Review protocol similar to active ingredient protocol Environmental fate and toxicological information will be considered Environmental fate and toxicological information will be considered Supplemental information may be obtained through use predictive tools approved by EPA Supplemental information may be obtained through use predictive tools approved by EPA

31 List of Approved Surfactants Recently completed a risk assessment of commonly used surfactants in herbicide products Recently completed a risk assessment of commonly used surfactants in herbicide products Resulted in a list of approved surfactants for use in Sensitive Areas of Rights-of-Way Resulted in a list of approved surfactants for use in Sensitive Areas of Rights-of-Way New requests for herbicide products containing surfactants that are not listed will have to undergo a review following the same criteria New requests for herbicide products containing surfactants that are not listed will have to undergo a review following the same criteria

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

33 Herbicide 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 ApprovedNot Approved Apply use restrictions Still unacceptable Acceptable Surfactants & other adjuvants

34 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 Rights-of-Way Management Regulations. July 1987 Legislation: 333 CMR 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-Way June 2010 Surfactant Ecological Risk Assessment (Wijnja, 2010) Reference: Wijnja, H Ecological Risk Assessment of Surfactants Associated with Herbicide Application in Rights-of-Way Areas. Massachusetts Department of Agricultural Resources. Boston, MA Ver 2.0 February 2011

35 Summary of Regulatory Review These levels of review and evaluation for registration and addition to the Sensitive Area Materials List and the rigorous regulatory process for rights-of-way are in place to ensure: These levels of review and evaluation for registration and addition to the Sensitive Area Materials List and the rigorous regulatory process for rights-of-way are in place to ensure: Protection from potential impacts on human health and the environment from the selective use of these herbicides Protection from potential impacts on human health and the environment from the selective use of these herbicides Allow the benefits of selective use of herbicides to maintain rights-of-way Allow the benefits of selective use of herbicides to maintain rights-of-way

36 Glyphosate First registered by EPA in 1974 First registered by EPA in 1974 Widely used non-selective herbicides Widely used non-selective herbicides Mode of Action: Inhibition of plant enzyme Mode of Action: Inhibition of plant enzyme Acute Toxicity (mammalian) Low by oral exposure (LD 50 >4320 mg/kg (rat) Low by oral exposure (LD 50 >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 sensitizer Not 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 ingredients Product formulations may cause irritation due to other ingredients

37 Glyphosate: Chronic Toxicity Dog study 1(yr): No effects; NOEL > 500 mg/kg/d Dog study 1(yr): No effects; NOEL > 500 mg/kg/d Rat (2 yr): decreased body weight, effects on eyes and liver at high doses (NOEL = 362 mg/kg/d Rat (2 yr): decreased body weight, effects on eyes and liver at high doses (NOEL = 362 mg/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 abnormalities Some fetuses had skelatal abnormalities No reproductive effects by glyphosate, AMPA, POEA No reproductive effects by glyphosate, AMPA, POEA

38 Glyphosate: Chronic Effects Carcinogenicity: Carcinogenicity: Animal studies have not shown evidence that exposure to glyphosate is linked to cancer Animal studies have not shown evidence that exposure to glyphosate is linked to cancer Classified as “Evidence of non-carcinogenicity in humans” Classified as “Evidence of non-carcinogenicity in humans” Endocrine Disruption: no evidence of effects Endocrine Disruption: no evidence of effects Fate in the Human Body: Fate in the Human Body: Any glyphosate taken in through skin or mouth goes through the body in less than a day Any glyphosate taken in through skin or mouth goes through the body in less than a day

39 Glyphosate: Environmental Fate In soil: break down by microbes to several smaller compounds, ultimately to CO 2, water and salts In soil: break down by microbes to several smaller compounds, ultimately to CO 2, water and salts Typical field half-life ranges is about 47 d Typical field half-life ranges is about 47 d Binds strongly to soil, immobile in soil Binds strongly to soil, immobile in soil In water: microbial break down In water: microbial break down Half-life: few days to 90 days Half-life: few days to 90 days No significant exposure to air expected (very low volatility) No significant exposure to air expected (very low volatility)

40 Glyphosate: Ecotoxicity Birds: Practically non-toxic (LD 50 >200 mg/kg) Birds: Practically non-toxic (LD 50 >200 mg/kg) Fish: slightly to practically non-toxic (LC mg/L); products: 1.3 – 1000 mg/L Fish: slightly to practically non-toxic (LC mg/L); products: 1.3 – 1000 mg/L Aquatic Invertebrates: Slightly to practically non- toxic (LC mg/L; products: 3-16 mg/L) Aquatic Invertebrates: Slightly to practically non- toxic (LC mg/L; products: 3-16 mg/L) Amphibians: Moderately to slightly toxic to product formulations (LC mg/L) Amphibians: Moderately to slightly toxic to product formulations (LC mg/L) Honey bees: practically non-toxic Honey bees: practically non-toxic Earthworm: practically non-toxic Earthworm: practically non-toxic

41 Triclopyr First registered by EPA in 1979 First registered by EPA in 1979 Selective herbicide used to control woody and herbaceous weeds in non-crop areas Selective herbicide used to control woody and herbaceous 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 hormones (auxins) Mode of Action: Mimics the effects of plant hormones (auxins)

42 Triclopyr Acute Toxicity (mammalian) Acute Toxicity (mammalian) Low by oral exposure (LD mg/kg (rat)) Low by oral exposure (LD mg/kg (rat)) Mildly irritating to corrosive to the eyes Mildly irritating to corrosive to the eyes Non-irritating to the skin of rabbits; skin sensitizer on guinea pigs Non-irritating to the skin of rabbits; skin sensitizer on guinea pigs Low toxicity by inhalation Low toxicity by inhalation Fate in body: Fate in body: Low rate of absorption Low rate of absorption Rapidly eliminated Rapidly eliminated

43 Triclopyr: Chronic Effects Rat study (13 weeks); Rat study (13 weeks); Effects on kidneys and liver at 20 mg/kg Effects on kidneys and liver at 20 mg/kg Dog study: ( d) Dog study: ( d) Effects on body weight, food consumption, blood chemistry, liver and kidneys at 20 mg/kg. Effects on body weight, food consumption, blood chemistry, liver and kidneys at 20 mg/kg. No effects at lower at 2.5 and 5.0 mg/kg doses No effects at lower at 2.5 and 5.0 mg/kg doses Fate in body: Elimination with 2 – 3 days Fate in body: Elimination with 2 – 3 days

44 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 carcinogenicity” Classified as: “Not classifiable as to human carcinogenicity” Reproductive and Developmental Effects Reproductive and Developmental Effects Rat and rabbit studies show low potential for effects Rat and rabbit studies show low potential for effects At high levels, decrease in live fetuses and skelatal effects At high levels, decrease in live fetuses and skelatal effects

45 Triclopyr: Environmental Fate In soil: breaks down to several smaller compounds, ultimately to CO 2, water and salts In soil: breaks down to several smaller compounds, ultimately to CO 2, water and salts Half-life ranges from 1.1 to 90 days Half-life ranges from 1.1 to 90 days Mobile in soil Mobile in soil In water, breaks down by exposure to sunlight In water, breaks down by exposure to sunlight Half-life is 1-10 days Half-life is 1-10 days No significant exposure to air expected (low volatility) No significant exposure to air expected (low volatility)

46 Triclopyr: Ecotoxicity Birds: Practically non-toxic (LD 50 >735 mg/kg) Birds: Practically non-toxic (LD 50 >735 mg/kg) Fish: Fish: TEA: practically non-toxic LC 50 >100 mg/L); TEA: practically non-toxic LC 50 >100 mg/L); BEE: moderately to highly toxic (LC mg/L ) BEE: moderately to highly toxic (LC mg/L ) Aquatic Invertebrates: Aquatic Invertebrates: TEA: practically non-toxic (LC mg/L) TEA: practically non-toxic (LC mg/L) BEE: moderately toxic (LC mg/L) BEE: moderately toxic (LC mg/L) Honey bees: practically non-toxic Honey bees: practically non-toxic

47 USDA Forest Service Risk Assessments Use Pattern Conifer release, site preparation, noxious weed control, and rights-of-way management Conifer release, site preparation, noxious weed control, and rights-of-way managementGlyphosate Human Health Assessment: Human Health Assessment: Low mammalian toxicity, very few specifics can be identified Low mammalian toxicity, very few specifics can be identified Developmental effects are most sensitive endpoint Developmental effects are most sensitive endpoint Formulations vary around the world; some studies from South America suggest potential endocrine and genotoxic effects Formulations vary around the world; some studies from South America suggest potential endocrine and genotoxic effects

48 Forest Service Risk Assessment Risk characterization: Hazard Quotient (HQ) Risk characterization: Hazard Quotient (HQ) HQ = Estimated Dose/ Reference Dose HQ = Estimated Dose/ Reference Dose Level of concern HQ > 1 Level of concern HQ > 1 Workers: minimal concern Workers: minimal concern General public: only concern for exposure by consuming vegetation shortly after treatment General public: only concern for exposure by consuming vegetation shortly after treatment Ecological Ecological LOC exceeded for Aquatic organisms for product formulations with POEA; LOC exceeded for Aquatic organisms for product formulations with POEA; Care should be taken with the use of such formulations near water bodies Care should be taken with the use of such formulations near water bodies

49 Forest Service Risk Assessment Triclopyr Level of Concern exceeded for: Level of Concern exceeded for: Workers based on worst-case scenarios Workers based on worst-case scenarios General public: only concern for exposure by consuming vegetation shortly after treatment General public: only concern for exposure by consuming vegetation shortly after treatment Ecological: Ecological: Level of Concern exceeded for large mammals and birds consuming contaminated vegetation Level of Concern exceeded for large mammals and birds consuming contaminated vegetation Sensitive non-target plants can be affected Sensitive non-target plants can be affected

50 MDAR Herbicide Assessment on Cape Cod Objectives: Evaluate the fate of herbicides used in utility rights-of-way in common soil on Cape Cod Evaluate the fate of herbicides used in utility rights-of-way in common soil on Cape Cod Evaluate the effects on groundwater and surface water for: Evaluate the effects on groundwater and surface water for: Human health Human health Ecological (aquatic life) effects Ecological (aquatic life) effects

51 Modeling of Pesticide Fate in Soils Fate in soil was simulated by EPA’s Pesticide Root Zone Model (PRZM) Fate in soil was simulated by EPA’s Pesticide Root Zone Model (PRZM) Input parameters include: Input parameters include: Application rate, chemical and environmental fate properties, soil and vegetation characteristics, meteorological data Application rate, chemical and environmental fate properties, soil and vegetation characteristics, meteorological data Output includes: Output includes: Herbicide concentration profile in soil Herbicide concentration profile in soil

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54 Groundwater Evaluation Exposure of herbicides to groundwater was simulated with SCI-GROW model Exposure of herbicides to groundwater was simulated with SCI-GROW model EPA-approved generic screening level model EPA-approved generic screening level model Simulates high-end estimates for groundwater concentration levels Simulates high-end estimates for groundwater concentration levels Simulates behavior on a vulnerable site: Simulates behavior on a vulnerable site: – Sandy soils – Low organic content (<1%) – Shallow groundwater (avg. 14 ft)

55 Simulated Groundwater Concentrations HerbicideSimulated Concentration (parts-per-billion, ppb) Health-Based Standard 1 or Health Value 2 (ppb) Imazapyr Glyphosate Fosamine Metsulfuron- methyl Triclopyr 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.

56 Comparison with Health-Based Standards 13,700 x lower 106,060 x lower 2,380 x lower 324,000 x lower 2450 x lower Note the Y-axis is expressed on a log-based scale!! Glyphosate

57 Surface Water Evaluation Exposure of herbicides to surface water was simulated with PRZM-EXAMS Exposure of herbicides to surface water was simulated 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 off, and volatilization; selected value for off-site drift – Input includes soil, vegetation and local climate data – Does not consider buffer zone Output includes simulated herbicide concentrations at various time intervals: Output includes simulated herbicide concentrations at various time intervals: – From initial peak concentration up to 90 day-concentration

58 Simulated Surface Water Concentrations Herbicide Simulated Concentration (parts-per-billion, ppb) Ecological Benchmark 1 or Toxicological Endpoint 2 (ppb) (Fish, acute effects) Imazapyr0.86>50,000 1 Glyphosate0.7321,500 1 Fosamine- ammonium 1.5>150,000 2 Metsulfuron- methyl ,000 2

59 Comparison with Aquatic Life Benchmarks Acute Effects Fish Invertebrates 800 x lower 29,000 x lower 3500 x lower 36,000 x lower

60 Conclusions ROW herbicide are applied at relatively low rates ROW herbicide are applied at relatively low rates Simulated concentrations in ground- and surface water are well below health-based and ecological standards Simulated concentrations in ground- and surface water are well below health-based and ecological standards These low exposure levels indicate minimal risk to human health and non-target organisms These low exposure levels indicate minimal risk to human health and non-target organisms

61 Further Reduction of Exposure Simulations represent worst-case scenario or high-end of exposure potential Simulations represent worst-case scenario or high-end of exposure potential Exposure is reduced by limited-spray zones and no-spray zones Exposure is reduced by limited-spray zones and no-spray zones No-spray zones include: No-spray zones include: 50 ft from private well 50 ft from private well 10 ft from surface water or wetland 10 ft from surface water or wetland

62 Summary Herbicides for vegetation in rights-of-way, aquatic systems and similar areas undergo rigorous regulatory review Herbicides for vegetation in rights-of-way, aquatic systems and similar areas undergo rigorous regulatory review Properties and effects have been well characterized Properties and effects have been well characterized Conservative risk assessments indicate low risks for humans and non-target organisms, except plants Conservative risk assessments indicate low risks for humans and non-target organisms, except plants Following all applicable regulations and label instructions should provide sufficient protection while allowing herbicides as effective tools Following all applicable regulations and label instructions should provide sufficient protection while allowing herbicides as effective tools

63 Hotze Wijnja, Ph.D. Environmental Chemist Massachusetts Department of Agricultural Resources Phone:

64 Resources MDAR, Division of Crop and Pest Services MDAR, Division of Crop and Pest Services es_pest_services.htm es_pest_services.htm es_pest_services.htm es_pest_services.htm EPA Office of Pesticide Programs EPA Office of Pesticide Programs National Pesticide Information Center (NPIC) National Pesticide Information Center (NPIC) and and USDA Forest Service USDA Forest Service


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