Presentation is loading. Please wait.

Presentation is loading. Please wait.

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

Similar presentations


Presentation on theme: "Hotze Wijnja, Ph.D. Division of Crop and Pest Services"— Presentation transcript:

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

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

4 1. EPA Regulates Pesticides Under Authority From:
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Requires registration of all pesticides by EPA Federal Food, Drug and Cosmetic Act (FFDCA) Requires EPA to set pesticide tolerances for all pesticides used in or on food Food Quality Protection Act (FQPA) 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. Analysis of aggregate exposure, cumulative effects, sensitive populations (infants), and endocrine-disrupting effects

6 EPA Registration Program
Evaluation of new and existing pesticides Registration of products for pest control 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 A product label is a legal document

7 Evaluation for Registration
Human health risk Short-term acute effects Long-term effects such as cancer and reproductive Aggregate exposure (food, water and residential) Cumulative risks (includes other pesticides) Occupational risks Effects on wildlife, fish and plants Acute and chronic Including endangered species

8 Evaluation for Registration
Human Health Risk Short-term acute effects Long-term effects such as cancer and reproductive Aggregate exposure (food, water and residential) Cumulative risks (includes other pesticides) Occupational risks Effects on wildlife, fish and plants Acute and chronic Including endangered species

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

10 Risk Cup Concept 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.

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

12 Review of Registered Pesticides
Programs for re-evaluation of registered pesticides Ensure adherence to the highest standards for protection of human health and the environment Registration review Re-evaluation on a regular cycle Special review 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 Registration of pesticides Licensing and certification of applicators Enforcing federal and state laws and regulations Pesticide Program Objectives Regulate the use of pesticides Protect human health and the environment

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

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

16 Registration Classification
Classification as State Restricted Use Pesticide based on: Potential for groundwater contamination Subsurface termiticide use Toxicity 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 Rights-of-Way management Sensitive Area Materials List Aquatic Herbicides: Licensed use of approved herbicides (those included in GEIR) 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 Scientific review of herbicide products includes: Physical and chemical characteristics EPA registration standard and status Primary and secondary data sources If necessary, additional data will be requested from registrant 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 Sensitive area restrictions include: 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)

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

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

23 Environmental Fate Evaluation
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 Chemical properties Application characteristics Soil and meteorological input

24 Toxicity Criteria Mammalian toxicity
Acute: LD50 values; Irritant effects Chronic/ Subchronic No Observed Adverse Effect Levels (NOAEL) Lowest Observed Adverse Effect Levels (LOAEL) Reproductive and developmental toxicity Carcinogenicity Mutagenicity

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

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

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

28 Risk Characterization
Based on comparison of predicted environmental concentrations with: “No Observed Effect Levels” or “Lowest Observed Effect Levels” LC50 values Hazard Index (HI), or Risk Quotient (RQ) 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 Concerns for potential effects on aquatic organisms Review protocol similar to active ingredient protocol Environmental fate and toxicological information will be considered 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 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

32 List of Approved Surfactants
Polyethoxylated ethylamines (POEA) Alkylphenol ethoxylates (APE) Alcohol ethoxylates (AE) Phosphate ester ethoxylates (PE) Organosilicones (OS) The need for re-evalution will be considered when new data become available

33 Herbicide Reviews for ROW
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 Active Ingredient & Product Surfactants & other adjuvants Approved Not Approved Apply use restrictions Acceptable Still unacceptable

34 Components of Herbicide Review Process for Sensitive Areas of Rights-of-Way
Legislation: 333 CMR Rights-of-Way Management Regulations DEQE/DFA Cooperative Agreement Relative to Section 4(1) (E) of 333 CMR Rights-of-Way Management Regulations. July 1987 HERBICIDE EVALUATION TECHNICAL UPDATE No. 1 Methods for the Evaluation of Herbicides for Use in Sensitive Areas of Rights-of-Way June 2010 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 Surfactant Ecological Risk Assessment (Wijnja, 2010) HERBICIDE EVALUATION TECHNICAL UPDATE No. 2 List of Approved Surfactants for Use in Sensitive Areas of Rights-of-Way – June 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 February 2011 Ver 2.0

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: 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

36 Glyphosate First registered by EPA in 1974
Widely used non-selective herbicides Mode of Action: Inhibition of plant enzyme Acute Toxicity (mammalian) Low by oral exposure (LD50 >4320 mg/kg (rat) Low by dermal exposure (skin, eye) (2 g/kg) Not a skin sensitizer Very low by inhalation (4.43 mg/L) Product formulations may cause irritation due to other ingredients

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

38 Glyphosate: Chronic Effects
Carcinogenicity: Animal studies have not shown evidence that exposure to glyphosate is linked to cancer Classified as “Evidence of non-carcinogenicity in humans” Endocrine Disruption: no evidence of effects Fate in the Human Body: 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 CO2, water and salts Typical field half-life ranges is about 47 d Binds strongly to soil, immobile in soil In water: microbial break down Half-life: few days to 90 days No significant exposure to air expected (very low volatility)

40 Glyphosate: Ecotoxicity
Birds: Practically non-toxic (LD50 >200 mg/kg) 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) Amphibians: Moderately to slightly toxic to product formulations (LC mg/L) Honey bees: practically non-toxic Earthworm: practically non-toxic

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

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

43 Triclopyr: Chronic Effects
Rat study (13 weeks); Effects on kidneys and liver at 20 mg/kg Dog study: ( d) 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 Fate in body: Elimination with 2 – 3 days

44 Triclopyr: Chronic Carcinogenicity
No tumors in male rats and mice (2 yr study) Increase of number of tumors in female rats and mice Classified as: “Not classifiable as to human carcinogenicity” Reproductive and Developmental Effects Rat and rabbit studies show low potential for 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 CO2, water and salts Half-life ranges from 1.1 to 90 days Mobile in soil In water, breaks down by exposure to sunlight Half-life is 1-10 days No significant exposure to air expected (low volatility)

46 Triclopyr: Ecotoxicity
Birds: Practically non-toxic (LD50 >735 mg/kg) Fish: TEA: practically non-toxic LC50 >100 mg/L); BEE: moderately to highly toxic (LC mg/L ) Aquatic Invertebrates: TEA: practically non-toxic (LC mg/L) BEE: moderately toxic (LC mg/L) 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 Glyphosate Human Health Assessment: Low mammalian toxicity, very few specifics can be identified Developmental effects are most sensitive endpoint 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) HQ = Estimated Dose/ Reference Dose Level of concern HQ > 1 Workers: minimal concern General public: only concern for exposure by consuming vegetation shortly after treatment Ecological LOC exceeded for Aquatic organisms for product formulations with POEA; Care should be taken with the use of such formulations near water bodies

49 Forest Service Risk Assessment
Triclopyr Level of Concern exceeded for: Workers based on worst-case scenarios General public: only concern for exposure by consuming vegetation shortly after treatment Ecological: Level of Concern exceeded for large mammals and birds consuming contaminated vegetation 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 effects on groundwater and surface water for: Human health Ecological (aquatic life) effects

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

52

53

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

55 Simulated 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 1750 1 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 324,000 x lower 2450 x lower 106,060 x lower 2,380 x lower Glyphosate Note the Y-axis is expressed on a log-based scale!!

57 Surface Water Evaluation
Exposure of herbicides to surface water was simulated with PRZM-EXAMS 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: From initial peak concentration up to 90 day-concentration

58 Simulated Surface Water Concentrations
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

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

60 Conclusions ROW herbicide are applied at relatively low rates
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

61 Further Reduction of Exposure
Simulations represent worst-case scenario or high-end of exposure potential Exposure is reduced by limited-spray zones and no-spray zones No-spray zones include: 50 ft from private well 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 Properties and effects have been well characterized 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

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

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


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

Similar presentations


Ads by Google