Pollution of water and bottom sediments of the polar front area in the Barents Sea with heavy metals

Pollution of the Barents Sea water and bottom sediments in the Polar Front area with heavy metals including Cu, Ni, Co, Cd, Hg, Zn, Pb and Cr has been considered based on the long-term data. The existence of a voluminous own database of Knipovich Polar Research Institute of Marine Fisheries and Oceanography (PINRO) on the content of metals in the surface layer of water and bottom sediments of the Barents Sea is the prerequisite for carrying out the research. At the first stage of the study, the data from 32 stations located in the Polar Front zone and obtained in the period from 2001 to 2013 have been derived and processed using GIS technologies and mathematical statistics from the database. Further, based on methods previously proposed by PINRO, the background values of the content of the listed metals in water and bottom sediments of the Polar Front, the zone of contact and transformation of the Atlantic and Arctic water masses have been calculated. In most cases, the values obtained have exceeded those established for neighboring water masses. As a result of the research, the maps of distribution of the pollution of sea water and bottom sediments with heavy metals have been made. Pollution is understood as the content of metals in concentrations exceeding the background level. It has been concluded about the persistent anthropogenic contamination of the Barents Sea Polar Front waters with some heavy metals, as well as of its bottom sediments with mercury in autumn period. The assumption has been made that the frontal zone accumulated the pollution coming from neighbouring contacting Atlantic and Arctic water masses. It has been shown that the pollution of the water in the frontal zone is mostly not accompanied by contamination of the underlying bottom sediments. With respect to the content of Ni, Cr and Pb in bottom sediments, one can speak of the detection of positive local geochemical anomalies.