PMRA Environmental Risk Assessment Scientific Evaluation and - PDF document

PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Overview Pest Management Regulatory Agency o The PMRA o Role of EAD Environmental Risk Assessment o Exposure assessment o Toxicology assessment Daniel G Sauvé, MSc. o Risk characterization Senior Evaluation Officer, Environmental Risk Section III Environmental Assessment Directorate o Risk mitigation o Conclusion 2 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada PMRA Organizational Chart PMRA History Executive Director Prior to April 1995: Environment Canada Agriculture and Terrestrial environment Registration Directorate (RD) Chief Registrar Office (CRO) Agri-Food Canada risk assessment Efficacy & phytotoxicity Strategic Planning, Financial and Business Policy, Communications and Coordination, assessment Fisheries and Oceans Operations Division (SPFBOD) Regulatory Affairs Directorate (PCRAD) and Registration Aquatic environment risk assessment Compliance, Laboratory Services and Regional Operations Directorate Value Assessment and Re- (CLSROD) evaluation Management Health Canada Directorate (VRD) Health Evaluation Human health risk assessment PMRA Directorate (HED) April 1995 Health Canada Environmental Assessment Directorate (EAD) 3 4 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Environmental Assessment Directorate Mandate of PMRA (EAD) • Protecting the health and environment of Canadians Main Activities and supporting Canadian competitiveness by o Assess scientific data on the ecotoxicology and environmental regulating pest control products (pesticides) and their fate and behaviour of pesticides; o use in an effective and transparent manner. 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. 5 6 1

PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Objectives of environmental risk Risk assessment framework assessment o Evaluate the likelihood that adverse ecological effects Problem formulation may 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 Risk characterization environment Risk mitigation options 7 8 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Environmental exposure assessment Fate and Behaviour in the Environment o Evaluate the potential exposure (direct and indirect) to plants, Phototransformation Foliar Interception insects and other animals of pesticide residues in water, food, air, surfaces, and dissipation soil and air; soil, water Volatilisation o Includes information on the quantity of pesticides to which an organism can be exposed and the frequency and duration of Surface Runoff Wash-off exposure; Applied Pesticide o Based on data on the fate and behaviour in the environment, Plant uptake modelling and monitoring in the field; Lateral flow Sorption / Transformation o Information on the active ingredient and the end-use product(s) Retention microbial (biotic) o For new chemicals and older already registered products chemical (abiotic) Leaching 9 10 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Data that may be required to assess Exposure Assessment exposure Abiotic Transformation o Physical-chemical properties o Phototransformation o Solubility, vapour pressure, K ow , pK a , UV absorption. o Soil o Transformation (abiotic and biotic) o Hydrolysis, phototransformation, biotransformation (soil and water) o Water aerobic/anaerobic. o Mobility o Air 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 12 2

PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Exposure Assessment Biotransformation (20-30 ° C) Abiotic Transformation o Hydrolysis o Soil o The pH can significantly influence the rate of hydrolysis (half- o Aerobic life) o Anaerobic (flooded) 500 4 450 3.5 400 o Aquatic systems 3 350 2.5 300 o Aerobic water Days days 250 2 200 o Water/sediment anaerobic 1.5 150 1 100 0.5 50 0 0 o Provides information on the identity, formation 4.5 7 9 pH and persistence of transformation products Chemical a Chemical b 13 14 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Exposure Assessment Mobility Adsorption/desorption o 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 ) o Leaching in soil column Koc = Kd ÷ % OC • o Thin layer soil Chromatography • Kd = distribution coefficient between soil and water • % OC= % organic carbon o Volatilization A high Koc = strong affinity to soil particle; A low Koc = highly mobile in the soil 15 16 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Exposure Assessment Terrestrial field Dissipation Studies 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. Applicants MUST consider the ecological regions of Canada 17 18 3

PMRA Environmental Risk Assessment Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Exposure Assessment Characteristics of a chemical that has the potential to leach into the soil, Cohen et al . 1984 Dissipation (aquatic environment) • 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 19 20 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Calculated GUS score classification system Assessment of the potential for leaching (Gustafson, 1989) (DIR2006-01) We consider: log log GUS t 4 K 1 2 OC 10 10 o The Cohen et al . 1984 criteria; soil • GUS : Groundwater Ubiquity Score o The GUS scores; • t½ soil = time required for the chemical to decline by 50% under o Field dissipation studies and modelling; field conditions; o Studies conducted with lysimeters; • Koc = soil water-organic carbon coefficient o Other field studies GUS Leaching potential o e.g.: Prospective groundwater studies > 2.8 Leacher o And, for re-evaluations, ground water monitoring >1.8 and < 2.8 Borderline leacher data. < 1.8 Non leacher 21 22 Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Scientific Evaluation and Decision-Making Process for Pest Control Products in Canada Risk assessment framework Environmental Hazards Assessment o Describes the types of effects that a pesticide Problem formulation may elicit on organisms and how these effects may vary according to the exposure; o Based on internationally accepted guidelines and Exposure assessment Hazards assessment surrogate species; o Determine ecotoxicological endpoints and dose- response (e.g.: LD 50 , NOEC, EC 25 ) Risk characterization o Identifies the most sensitive organisms and helps predict the potential adverse effects to non-target Risk mitigation organisms options 23 24 4