Predicting the environmental fate and ecotoxicological and toxicological effects of pesticide transformation products

摘要

Following the application of pesticides during normal agricultural practice theseudcompounds can degrade to form transformation products. When assessing theudrisks posed by pesticides it is important to include any additional risks posed byudthese compounds. Current guidance within the EU suggests that dataudrequirements for transformation products during the risk assessment do notudnecessarily need to be addressed with experimental studies but alternativeudtechniques can be explored and used. Therefore the aim of this research was toudinvestigate and develop pragmatic approaches for assessing the fate and effectsudof transformation products in the absence of experimentally determined data.udApproaches designed to provide information on the physico-chemical properties,udenvironmental parameters, ecotoxicology and toxicology of pesticideudtransformation products are explored and evaluated, and recommendations madeudon how to obtain the most appropriate estimates of these factors.udHydrophobicity, dissociation constant, soil sorption, daphnid aquaticudecotoxicology and rat oral lethality can all be estimated with confidence.udMoreover, approaches were developed to I) indicate whether a transformationudproduct may exhibit pesticidal activity and subsequently estimate its acuteudaquatic ecotoxicity in the absence of experimental data, 2) combine well knownudtechniques and experimental data to obtain estimates of transformation productudmutagenicity with limited risk of obtaining false negatives and 3) prioritiseudtransformation products of most concern to drinking water supplies and itsudconsumers.udOverall, recommendations are made throughout this thesis on appropriateudapproaches and methods for generating estimates of transformation productudproperties, ecotoxicity and toxicity for use in risk assessment and prioritisationudframeworks.ud