The Role of Manganese Dioxide in Secondary Pollution of Freshwater Basins (According to Experimental Modeling Data)

— Experimental modeling was carried out for reductive dissolution of manganese(IV) oxyhydroxides of bottom sediments during the periods of hypoxia in freshwater basins. Along with iron(III) oxyhydroxides, those of Mn cause the secondary pollution of the water mass. It was shown that the hypoxia periods in the water mass might cause the accumulation of not only dissolved forms of manganese but also of trace elements adsorbed on manganese(IV) oxyhydroxides. The mass ratios to manganese of trace element impurities passing into a (Δ[ i ]/Δ[Mn] × 10 3 ) solution were estimated: Li, 0.41; Rb, 1.65; Cs, 0.010; Sr, 31.7; Ba, 50.3; Co, 0.093; Ni, 0.65; Сd, 0.046; Y, 0.070; La, 0.030; Ce, 0.086; Tl, 0.015; and U, 0.23.