Sulfuric Compounds in the Surface Layer of Bottom Deposits in the Mouth Reach of the Northern Dvina River

The distribution of reduced sulfuric compounds in the surface layer of bottom deposits in the Northern Dvina mouth was examined. The natural biogeochemical processes and anthropogenic pollution are found to cause the formation and accumulation of reduced sulfuric compounds (mostly pyrite and organic forms) in bottom deposits. The concentration of individual forms of sulfur and its total concentration are found to vary widely from year to year. The most intense accumulation of the total reduced sulfur is recorded near the wastewater discharge sites of pulp and paper mills.