Long-term dynamics of total mercury in surficial bottom sediments of the Volga River’s reservoir in central Russia

The long-term dynamics of mercury in bottom sediments of Uglich Reservoir were examined. Samples of the 0–5-cm surface layer of bottom sediment collected during research expeditions in 1958, 1977, 1991, and 2012 were analyzed. An increase in the average mercury concentration from 1958 to 1977 (0.440 ± 0.039 and 0.668 ± 0.065 mg/kg d.w., respectively) was followed by a decrease in 2012 (0.260 ± 0.021 mg/kg d.w.). During all years except 1991, a significant correlation was found between mercury content and the amount of organic matter in the sediments ( r = 0.54–0.87, p