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Oksana Stoylar, her students and other University colleagues focus their efforts on identifying the presence of potential toxins in surface waters, and freshwater fauna. Using unionids and other freshwater bivalves as indicator organisms they use biochemical and molecular techniques to assess the health of freshwater ecosystems and the potential human risks associated with use of these streams for drinking water or recreation. Metallothioneins, metal buffering and stress proteins, are studied by the size-exclusion chromatography and by ion-exchange liquid chromatography. Their content in the tissue and metal content in them are also measured. The oxidative defense system is characterised by examining levels of superoxide dismutase (Cu,Zn-SOD and Mn-SOD), measuring catalase activity, glutathione levels (GSH and GSSG), lipid peroxidation measured as thiobarbituric acid reacting substance (TBARS) production; protein carbonyls. The microsomal biotransformation system is studied by the ethoxyresorufin-O-deethylase (EROD) and GSH-transferase activity, and other biomarkers, such as lysosomal membrane stability, acetylcholinesterase activity (neurotoxicity), vitellogenin level (endocrine disruption), DNA damage are also used as indicators of stream health. By correlating levels of these contaminants with routine measurements of temperature, manganate oxydizability, pH, hardness, nitrites, nitrates, phosphates metals (Cu, Zn, Mn, Fe, Cd, Pb) in water, the laboratory provides a broad assessment of overall ecosystem health.
Dreissana considered invasive in the US, are native to the streams in the Eastern Europe, but no less destructive in their native habitat.