Assessment of vulnerable freshwater ecosystems and various aquatic effluents by means of ecotoxicological assays

Abstract

A battery of ecotoxicological assays of different trophic chain levels has been performed for water and sediment samples of two Greek vulnerable freshwater ecosystems (Karla Lake in Thessaly Region and Koronia Lake in Central Macedonia Region, respectively). These lakes, despite remediation programs, are still characterized by varied water quality. Furthermore, the quality of aquatic reservoirs aimed for human consumption as well as this of treated and untreated wastewater samples was also assessed through these bioassays. The outcome of the present research shows that condition of the studied lake ecosystems is still poor and intervention is needed for rectification of their continuous decline. Samples from treated municipal wastewater from the same regions were of medium to satisfactory quality, as measured by ecotoxicological assays. Despite causative relationships between burdened physicochemical parameters and increased toxicity, this toxicity could not always be attributed to these parameters. Results of bioassays in combination with standard physicochemical measurements of water samples may aid the integrated assessment of environmental risk arising from presence or release of these water samples in the ecosystem.