. 2016. Comparison and evaluation of pesticide monitoring programs using a process-based mixture model. Environmental Toxicology and Chemistry, 35 (12). 3113-3123. 10.1002/etc.3492 Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.This article is protected by copyright. All rights reserved
Accepted PreprintThis article is protected by copyright. All rights reserved Abstract: A number of European countries run large scale pesticide monitoring schemes in watersheds aimed at identifying and evaluating the presence of pesticide residues in the environment. These schemes provide national and regional scale assessments of pesticide concentrations within the context of environmental quality assessment, aiming to ensure some degree of ecological protection. This study is aimed at evaluating the joint effects of the pesticide mixtures detected in monitoring programs, using a process based mixture modelthat was parameterised for Daphnia magna. In total over 15,000 samples containing over 1 million individual measurements were evaluated for effects.It was found that there are only a small number of places where we can expect to have effects on daphnids, based on measured concentrations. The most polluted samples would cause extinction of a daphnid population within only 30 hrs. The results show that effects are mostly triggered by a limited nr of pesticide residues at locations with high emissions. It was also shown that the analytical detection limits are basically too high to exclude mixture effects. So despite all the effort that is put into chemical monitoring programmes it remains a challenge to make statements on whether or not the environment is protected. The paper ends with recommendations for a different setup of monitoring programs to improve on this. This article is protected by copyright. All rights reserved