Multi-marker study of the responses of the Unio tumidus from the areas of small and micro hydropower plants at the Dniester River basin, Ukraine

The aim of this study was to evaluate the environmental impact of the hydropower plants (HPPs) utilizing the bivalve mollusk Unio tumidus. The upstream and downstream of the dam sites of small HPPs and micro HPPs were examined. The indices of stress and toxicity were determined in the digestive gland, hemocytes (lysosomal integrity) and honads (alkali-labile phosphates, ALP). The mollusks from the reservoirs of small HPPs show the depletion of the cholinesterase, the highest glutathione S-transferase, ALP (by ~5 times) and metallothionein levels, low concentration of glutathione, the highest extralysosomal activity of the cathepsin D (CTD), the loss of the lysosomal integrity and a high copper concentration, indicating pollution from agricultural and municipal wastes. The specimens from the micro HPP area had the highest level of glutathione and lipid peroxidation and a low Cu,Zn-SOD activity and low morphological indexes.