Pesticide mixtures in the Swedish streams: environmental risks, contributions of individual compounds and consequences of single-substance oriented risk mitigation
- Published
- Accepted
- Subject Areas
- Agricultural Science, Ecotoxicology, Environmental Contamination and Remediation, Environmental Sciences
- Keywords
- Kaplan-Meier method, mixture risk assessment, concentration addition, maximum cumulative ratio, chemical monitoring, mixture risk management
- Copyright
- © 2017 Gustavsson et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2017. Pesticide mixtures in the Swedish streams: environmental risks, contributions of individual compounds and consequences of single-substance oriented risk mitigation. PeerJ Preprints 5:e2779v1 https://doi.org/10.7287/peerj.preprints.2779v1
Abstract
The paper presents the ecotoxicological assessment and environmental risk evaluation of complex pesticide mixtures occurring in freshwater ecosystems in southern Sweden. The evaluation is based on the data collected between 2002 and 2013 by the Swedish pesticide monitoring program and includes 1308 individual samples, detecting mixtures of up to 54 pesticides (modal=8). The environmental risk of 77% of the samples exceeded acceptable levels, based on an assessment using Concentration-Addition and Swedish Water Quality Objectives (WQO) for the individual pesticides. Algae were the most sensitive organism group. However, the analytical detection limits, especially for insecticides, are currently insufficient to analyze concentrations at or near their WQO’s. Thus, the risk of the analyzed pesticide mixtures to crustaceans and fish is currently systematically underestimated.
Throughout the monitoring the risk associated with pesticide mixtures is often driven by only 1-3 compounds. However, the risk-drivers differ substantially between sites and samples, so that 83 of the 141 monitored pesticides need to be included in the assessment to account for 95% of the risk at all sites and years.
Single-substance oriented risk mitigation measures that would ensure that each individual pesticide is present at 95% of its individual WQO at maximum, would also reduce the mixture risk, from a median risk quotient of 2.7 to a median risk quotient of 2.3. However, acceptable total risk levels would still be exceeded in more than 70% of the samples.
Author Comment
This is a preprint version of a manuscript submitted to a peer-reviewed journal.