PMRA Environmental Risk Assessment Pest Management Regulatory Agency Environmental Risk Assessment Daniel G Sauvé, MSc. Senior Evaluation Officer, Environmental Risk Section III Environmental Assessment Directorate Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Overview o The PMRA o Role of EAD o Exposure assessment o Toxicology assessment o Risk characterization o Risk mitigation o Conclusion 2 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada PMRA History Prior to April 1995: Environment Canada Agriculture and Terrestrial environment risk assessment Agri-Food Canada Efficacy & phytotoxicity Coordination, assessment Fisheries and Oceans and Registration Aquatic environment risk assessment Health Canada Human health risk assessment PMRA April 1995 Health Canada 3 1
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada PMRA Organizational Chart Executive Director Registration Directorate (RD) Chief Registrar Office (CRO) Strategic Planning, Financial and Business Policy, Communications and Operations Division (SPFBOD) Regulatory Affairs Directorate (PCRAD) Compliance, Laboratory Services and Regional Operations Directorate Value Assessment and Re- (CLSROD) evaluation Management Directorate (VRD) Health Evaluation Directorate (HED) Environmental Assessment Directorate (EAD) 4 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Mandate of PMRA • Protecting the health and environment of Canadians and supporting Canadian competitiveness by regulating pest control products (pesticides) and their use in an effective and transparent manner. 5 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Environmental Assessment Directorate (EAD) Main Activities o Assess scientific data on the ecotoxicology and environmental fate and behaviour of pesticides; o Conduct environmental risk assessments 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. 6 2
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Objectives of environmental risk assessment o Evaluate the likelihood that adverse ecological effects may occur (or are occurring) following exposure to pesticides and/or their transformation products o Determine if changes in the use pattern (or proposed use pattern) are required to better protect the environment 7 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Risk assessment framework Problem formulation Exposure assessment Hazards assessment Risk characterization Risk mitigation options 8 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Environmental exposure assessment o Evaluate the potential exposure (direct and indirect) to plants, insects and other animals of pesticide residues in water, food, soil and air; o Includes information on the quantity of pesticides to which an organism can be exposed and the frequency and duration of exposure; o Based on data on the fate and behaviour in the environment, modelling and monitoring in the field; o Information on the active ingredient and the end-use product(s) o For new chemicals and older already registered products 9 3
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Fate and Behaviour in the Environment Phototransformation Foliar Interception air, surfaces, and dissipation soil, water Volatilisation Surface Runoff Wash-off Applied Pesticide Plant uptake Lateral flow Sorption / Transformation Retention microbial (biotic) chemical (abiotic) Leaching 10 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Data that may be required to assess exposure o Physical-chemical properties o Solubility, vapour pressure, K ow , pK a , UV absorption. o Transformation (abiotic and biotic) o Hydrolysis, phototransformation, biotransformation (soil and water) aerobic/anaerobic. o Mobility o Leaching, volatilization. o Field Dissipation (DIR2006-01) o Fate and mobility at sites representative of pesticide use in various regions in Canada o Bioaccumulation Ref: 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). 11 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Abiotic Transformation o Phototransformation o Soil o Water o Air 12 4
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Abiotic Transformation o Hydrolysis o The pH can significantly influence the rate of hydrolysis (half- life) 500 4 450 3.5 400 3 350 2.5 300 Days days 250 2 200 1.5 150 1 100 0.5 50 0 0 4.5 7 9 pH Chemical a Chemical b 13 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Biotransformation (20-30 ° C) o Soil o Aerobic o Anaerobic (flooded) o Aquatic systems o Aerobic water o Water/sediment anaerobic o Provides information on the identity, formation and persistence of transformation products 14 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Mobility o Adsorption/desorption o Leaching in soil column o Thin layer soil Chromatography o Volatilization 15 5
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Adsorption/desorption o The tendency of a pesticide to be a d sorbed on soil particles can be expressed as the soil water-organic carbon 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 16 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Terrestrial field Dissipation Studies • Shows the fate and mobility of pesticides and their transformation products on sites representative of areas where the proposed product is to be used in Canada. 17 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Terrestrial field Dissipation Studies Applicants MUST consider the ecological regions of Canada 18 6
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Dissipation (aquatic environment) 19 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Characteristics of a chemical that has the potential to leach into the soil, Cohen et al . 1984 • Water solubility > 30 ppm • K d < 5 and most often < 1 or 2 mL/g • K oc < 300 to 500 mL/g • Henry’s Law Constant < 10 -2 atm· m 3 /mole • Negatively charged (either completely or partially) at environmentally relevant pH • Hydrolysis half-life > 25 weeks • Photolysis half-life > 1 week • Soil half-life > 2 to 3 weeks 20 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Calculated GUS score classification system (Gustafson, 1989) (DIR2006-01) log log GUS t 4 K 1 2 OC 10 10 soil • GUS : Groundwater Ubiquity Score • t½ soil = time required for the chemical to decline by 50% under field conditions; • Koc = soil water-organic carbon coefficient GUS Leaching potential > 2.8 Leacher >1.8 and < 2.8 Borderline leacher < 1.8 Non leacher 21 7
PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Assessment of the potential for leaching We consider: o The Cohen et al . 1984 criteria; o The GUS scores; o Field dissipation studies and modelling; o Studies conducted with lysimeters; o Other field studies o e.g.: Prospective groundwater studies o And, for re-evaluations, ground water monitoring data. 22 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Risk assessment framework Problem formulation Exposure assessment Hazards assessment Risk characterization Risk mitigation options 23 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Environmental Hazards Assessment o Describes the types of effects that a pesticide may elicit on organisms and how these effects may vary according to the exposure; o Based on internationally accepted guidelines and surrogate species; o Determine ecotoxicological endpoints and dose- response (e.g.: LD 50 , NOEC, EC 25 ) o Identifies the most sensitive organisms and helps predict the potential adverse effects to non-target organisms 24 8
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