Exposure and toxicity of mixtures of plant protection products (PPPs) in the environment under Norwegian conditions. Evaluation of a cumulative environmental risk assessment of PPPs

This project was performed to improve the environmental cumulative risk assessment (CRA) of mixtures of plant protection products detected by the Norwegian Agricultural Environmental Monitoring Programme (JOVA) in Norwegian surface waters. Existing ecotoxicity data were compiled and reduced the assessment uncertainty compared to previous risk assessments. Ecotoxicity tests verified that the cumulative toxicity of ecologically-relevant environmental mixtures was fairly well predicted for algae, daphnia and aquatic plants. The results from the ecotoxicity tests were used to evaluate the assessment factor used in the risk assessment, and the improved data used in the CRA of plant protection products in the JOVA monitoring performed in 2013. Three of the six investigated sites had risk quotients indicative of environmental risk. Mitigation measures based on the identification of the main risk drivers were discussed and include consideration of no-spray zones, grassed buffer strips, reduced doses and patch spraying, and pesticide risk maps.