Geochemical Assessment of the Modern Sediments of a Lake in the North of Russia

Core sediment (sapropel) samples were collected from Lake Okunozero, the Republic of Karelia, Russia, to assess distribution heavy metals and their main fractions, probable sources pollution, potential ecological toxicological risks for water body. Heavy metal concentrations measured by mass spectrometry method using an XSeries-2 ICP-MS. The sequential extraction sapropel was performed scheme Tessier. According Russian Interstate Standard (GOST), Okunozero is suitable use in agriculture. exceedances regional background levels detected only Pb Cd. In accordance with Pollution Load Index (PLI) Potential Ecological Risk (RI), no ecotoxicological risk researched sediments found. A significant correlation between some investigated established. Most insoluble mineral phase (Mn et al.) or associated organic matter (Cu, Zn, Mo, Ni). Only Mn, Cd, found available fraction 13 24% total content sediments. Other less fraction.