3/1/2016 Pest Management Regulatory Agency Overview Environmental Risk Assessment o The PMRA o Role of EAD • Daniel G Sauvé, MSc. • Senior Evaluation Officer, Environmental Risk Section III o Exposure assessment • Environmental Assessment Directorate o Toxicology assessment o Risk characterization March 11 th , 2016 o Risk mitigation o Conclusion 2 Environmental Assessment Directorate Mandate of PMRA (EAD) • Protecting the health and environment of Canadians and o Assess scientific data on the ecotoxicology and supporting Canadian competitiveness by regulating pest environmental fate and behaviour of pesticides; control products (pesticides) and their use in an effective o Conduct environmental risk assessments and transparent manner. o Recommend mitigation measures; o Document scientific literature o Participate in scientific committees within PMRA, HC and other departments and institutions (USEPA, OECD, NAFTA, etc.) o Other projects: Improvment of risk assessment methods, buffer zones, water modeling, Tech teams, etc. 3 4 Objectives of environmental risk Risk assessment framework assessment o Evaluate the likelihood that adverse ecological effects may Problem formulation occur (or are occurring) following exposure to pesticides and/or their transformation products Exposure assessment Hazards assessment o Determine if changes in the use pattern (or proposed use pattern) are required to better protect the environment Risk characterization Risk mitigation options 5 6 1
3/1/2016 Environmental exposure assessment Fate and Behaviour in the Environment Phototransformation Foliar Interception o Evaluate the potential exposure (direct and indirect) to plants, insects air, surfaces, and dissipation and other animals of pesticide residues in water, food, soil and air; soil, water o Includes information on the quantity of pesticides to which an organism Volatilisation can be exposed and the frequency and duration of exposure; o Based on data on the fate and behaviour in the environment, modelling Surface Runoff Wash-off and monitoring in the field; Applied Pesticide o Information on the active ingredient and the end-use product(s) Plant uptake o For new chemicals and older already registered products Lateral flow Sorption / Transformation Retention microbial (biotic) chemical (abiotic) Leaching 7 8 Data that may be required to assess Exposure Assessment exposure Abiotic Transformation o Physical-chemical properties o Solubility, vapour pressure, K ow , pK a , UV absorption. Phototransformation o o Transformation (abiotic and biotic) o Soil o Hydrolysis, phototransformation, biotransformation (soil and water) aerobic/anaerobic. o Water o Mobility o Air o Leaching, volatilization. o Field Dissipation (DIR2006-01) o Fate and mobility at sites representative of pesticide use in various Hydrolysis regions in Canada o o The pH can significantly o Bioaccumulation influence the rate of Ref: hydrolysis (half-life) 1. Guidelines for Determining Environmental Chemistry and Fate of Pesticides (T- 1-255). 2. Harmonization of environmental chemistry and fate data requirements for chemical pesticides under NAFTA(DIR2003-03). 9 10 Exposure Assessment Exposure Assessment Mobility Biotransformation (20-30 ° C) o Adsorption/desorption o Soil o Aerobic o Anaerobic (flooded) o Leaching in soil column o Aquatic systems o Volatilization o Aerobic water/sediments o Anaerobic Water/sediment o Provides information on the identity, formation and persistence of transformation products 11 12 2
3/1/2016 Exposure Assessment Exposure Assessment Adsorption/desorption Terrestrial field Dissipation Studies • Shows the fate and mobility of pesticides and their o The tendency of a pesticide to be a d sorbed on soil particles transformation products on sites representative of areas can be expressed as the soil water-organic carbon where the proposed product is to be used in Canada. coefficient (K oc ) – Koc = Kd ÷ % OC – Kd = distribution coefficient between soil and water – % OC= % organic carbon A high Koc = strong affinity to soil particle; A low Koc = highly mobile in the soil 13 14 Exposure Assessment Exposure Assessment Dissipation (aquatic environment) Terrestrial field Dissipation Studies • Applicants MUST consider the ecological regions of Canada • Crosswalk with EU countries 15 16 Leaching Leaching Calculated GUS score classification system (Gustafson, 1989) Characteristics of a chemical that has the potential to leach into (DIR2006-01) the soil, Cohen et al . 1984 • Water solubility > 30 ppm log log GUS t 4 K • K d < 5 and most often < 1 or 2 mL/g 1 2 OC 10 10 soil • K oc < 300 to 500 mL/g • GUS: Groundwater Ubiquity Score • Henry’s Law Constant < 10 -2 atm· m 3 /mole • t½ soil = time required for the chemical to decline by 50% under • Negatively charged (either completely or partially) at field conditions; environmentally relevant pH • Koc = soil water-organic carbon coefficient • Hydrolysis half-life > 25 weeks GUS Leaching potential • Photolysis half-life > 1 week > 2.8 Leacher • Soil half-life > 2 to 3 weeks >1.8 and < 2.8 Borderline leacher < 1.8 Non leacher 17 18 3
3/1/2016 Leaching Risk assessment framework Assessment of the potential for leaching We consider: The Cohen et al . 1984 criteria; o Problem formulation The GUS scores; o Field dissipation studies and modelling; o Studies conducted with lysimeters; o Exposure assessment Hazards assessment Other field studies o o e.g.: Prospective groundwater studies And, for re-evaluations, ground water monitoring data. o Risk characterization Risk mitigation options 19 20 Environmental Hazards Assessment Toxicity Tests o Short term (acute) o Describes the types of effects that a pesticide may elicit on organisms and how these effects may vary o e.g.: LC 50 , LD 50 , LR 50 according to the exposure; LD 50 = dose at which 50% of the population dies o Based on internationally accepted guidelines and surrogate species; o Long term (chronic) o Determine ecotoxicological endpoints and dose- o e.g.: NOEC, LOEC, NOEL, LOEL response (e.g.: LD 50 , NOEC, EC 25 ) o Identifies the most sensitive organisms and helps NOEL= No effect level predict the potential adverse effects to non-target o Species Sensitivity Distribution (SSD) when data is organisms available o E.g.: HD 5 o Lab vs. Field 21 22 Non-Target Organisms: Terrestrial Non-Target Organisms: Invertebrates Terrestrial Invertebrates Beneficial Predators and parasites Honey bee ( Apis mellifera) Wasps: The Crab spider, Tricogramma – predator of aphids (parasitic wasp) Misumena vatia The Ladybird beetle Earth worms predator of aphids and ( Eisenia sp) scale insects Harmonia axyridis 23 24 4
3/1/2016 Non-Target Organisms: Non-Target Organisms: Terrestrial vertebrates Terrestrial vertebrates Mammals o Mammalian toxicity studies are assessed by the Health o Birds Bobwhite quail Evaluation Directorate for human safety ( Colinus virginianus) Zebra finch o The typical endpoints used by EAD to Mallard duck ( Taeniopygia guttata ) assess the risk to wild mammals are the ( Anas platyrhynchos) acute oral toxicity and 2-generation Reproduction. o Studies conducted with rats and/or mice 25 26 Non-Target Organisms: Non-Target Organisms: Freshwater Terrestrial Vascular plants o Invertebrates Daphnia Crustaceans: Daphnia (Water flea) o Seedling emergence (Acute toxicity and reproduction) o Vegetative vigour Bluegill Sunfish o Fish o Warm water (Blue-gill sunfish) o Cold water (Rainbow trout) Rainbow Trout (Acute toxicity, Early life stage (ELS) and full life cycle) o Amphibian o Often, fish study is used as a surrogate 27 28 Non-Target Organisms: Non-Target Organisms: Estuarine / marine Freshwater plants (Algae and vascular plants) o Crustaceans: Acute toxicity and Chronic Green alga (Selenastrum capricornutum) o Mollusc embryo Larvae or shell deposition o Fish o Acute toxicity Cyanobacteria ( Anabaena sp.) o Salinity challenge test o Algae (1 species) o Marine diatom Duckweed (Lemna gibba) Sheepshead minnow Cyprinodon variegatus 29 30 5
Recommend
More recommend
