Researchers from IMDEA Water (Spain), Wageningen University and Alterra (The Netherlands), and the University of Natural Resources and Life Sciences (Austria), have carried out a study in the Danube River with benthic invertebrates to identify key stress factors that impact the aquatic ecosystem.
The study evaluated correlations between several groups of chemical and non-chemical stressors (i.e., hydromorphological alterations, physico-chemical parameters, organic and inorganic pollutants) and biological indices commonly used for the ecological status assessment of aquatic ecosystems. It also evaluated the relative contribution of contaminants and other abiotic parameters to the structural and biological trait variation of the invertebrate community.
The results show that the variation in the structure and trait composition of the invertebrate community is mainly explained by habitat and water quality parameters, whereas hydromorphological alterations play a less important role. Among the water quality parameters, physico-chemical parameters such as suspended solids, nutrients or dissolved oxygen contributed to a larger part of the variation in the invertebrate community, as compared to metals or the organic contaminants that were measured.
The research also indicated that most biological indices significantly correlate to parameters related to habitat and physico-chemical conditions, thus having less relevance for the identification of hot-spots primarily impacted by emerging pollutants. Moreover, this study points out some key multiple stressor groups (e.g. pharmaceuticals and nutrients) that should be further investigated in ecotoxicological studies.
The full article can be downloaded from here.