Cause-effect relations of key pollutants on the European rivers biodiversity (KEYBIOEFFECTS)

The overall objective of the research and training network KEYBIOEFFECTS was to provide young scientists with the skills and knowledge needed to assess the effects of pollution (with specific focus on key pollutants) on the biodiversity of European rivers and to transfer this knowledge to different stakeholder groups. Recognizing the importance of understanding cause-effect relationships in protecting biodiversity, KEYBIOEFFECTS focused on the development of novel conceptual and methodological approaches in relating chemical pollution of aquatic ecosystems and ecological alterations in these systems. This understanding is essential for the analysis of the impairment of water quality and the good ecological status, demanded by Water Framework Directive (WFD). The network covered a wide range of scientific disciplines and more than 18 young scientists (among them 12 PhD students) were involved in research concerning the identification of key toxicants, assessment of their bioavailability, fate, transport and biological effects on different ecosystem levels (organisms, populations, ecosystems).

One of the PhD-positions was established at ECT. The main objective of this PhD was to evaluate the transfer of key toxicants and effects caused by this transfer along simplified food chains (sediment to fish via sediment-dwelling organisms) by assessing the internal concentrations and effects on fish using, for example, biomarkers as endpoints. Sediment bioaccumulation studies were performed with the benthic worm Lumbriculus variegatus exposed to selected model compounds. Subsequently, juvenile growth studies were performed with model fish species (zebrafish or rainbow trout) exposed via contaminated live worms. A newly established passive dosing method was used to produce worms with a known body burden of the compounds. Effects on fish mortality, growth, behaviour and feed conversion were investigated to link effect data to measured whole body concentrations. Specific effects on two biomarker genes involved in the defence mechanism of fish were also investigated: abcb1, encoding for P-glycoprotein, which is involved in the transport and excretion of xenobiotic compounds, and cyp1a, encoding for cytochrome P450-1A, which is involved in metabolisation of xenobiotic compounds. Overall, the results of KEYBIOEFFECTS demonstrated that chemical pollution still poses a risk for the ecological integrity of European rivers. As outcome of the project several innovative and sensitive tools (e.g. new sampling strategies, experimental approaches, analytical and bio-analytical methods, methods for data treatment and modelling) were developed and a guideline with practical recommendations was prepared, which may contribute to the improvement of environmental monitoring and risk assessment.