GEOCHEMICAL SPECIFIC FEATURES OF AQUATIC LANDSCAPES OF THE NORTHERN DVINA RIVER MOUTH AREA.

The paper is based on results of long-term complex environmental-geochemical studies of aquatic landscapes in the Northern Dvina River mouth area. Northern Dvina River is one of the major waterways European territory of Russian Subarctic. Specific natural conditions and a high level of human impact have a significant impact on the formation and operation of complex aquatic landscape-geochemical systems of the Northern Dvina. In this connection, the authors considered in detail both natural and anthropogenic factors of migration priority pollutants - heavy metals - in the river waters and sediments. The features simultaneous spatial and radial distribution of Cu, Ni, Zn, Pb, Cd and Cr components in the aquatic landscapes of the Northern Dvina mouth area are studied. The values of the main physical and chemical parameters, levels of gases content, organic substances in water and bottom sediments, their lithology and granulometric composition were determined. Researches have shown a high spatial and temporal variability in conditions of distribution of heavy metals in aquatic landscapes of the Northern Dvina mouth area, caused by influence of specific physical and chemical conditions, hydrodynamic conditions and lithology water systems, as well as features of the geography of industrial and residential areas. In the waters identified exceedances of existing maximum permissible concentrations for fishery waters for copper throughout the study area, and chromium and zinc in the river mouth area. The relationship between the increase of the heavy metals concentrations in the bottom sediments and the increase of the fine silt fraction and anthropogenic influence has been found. The highest concentrations of several heavy metals found in the sediments at the site the waters of the Bakaritsa port - Arkhangelsk city, as well as in the river mouth area near of large power generation enterprises and woodworking industries. In the sediments of the river mouth area have been found to have elevated lead concentrations relative to the geochemical background of the study area. Thus, the content of heavy metals in aquatic landscapes of the Northern Dvina River mouth area is low and the pollution is local. [ABSTRACT FROM AUTHOR]