Biomarkers to assess effects of plant protection product mixtures on fish
The NAWA-SPEZ studies of 2012 to 2017 detected excessive amounts of plant protection product. s (PPP) in swiss streams that are under agricultural pressure. PPP occur in concentrations that pose a chronic risk to fish. In addition, most PPP are present as mixtures which are presumably more toxic than the individual substances. Additional stressors are increases in water temperature, habitat changes and diseases. To protect fish in Swiss surface waters, we need to know more about the effects of PPP mixtures on fish health, especially in combination with other stressors.
As a first step, a literature review and risk assessment were carried out to prioritise high-risk pesticides for fish and to identify sensitive native fish species and life stages. Based on this, this project aims to (i) assess the effects of a relevant mixture of PPP on the health of juvenile brown trout, (ii) assess whether PPP increase the susceptibility of fish to other stressors such as increased water temperature and proliferative kidney disease (PKD), (iii) identify which parameters are best suited to monitor the effects of PPPs in native fish. Using a set of sensitive molecular biomarkers, the sublethal effects of PPP on fish under the influence of additional stress factors will be assessed.