The abundances of exchangeable, organic-bonded, and strongly bonded mineral species of Fe, Mn, Zn, Ni, Cr, Cu, Pb, and Co were determined in samples of bottom sediments from five estuaries of the basins of the White and Barents Seas by using a modified sequential extraction method, which was initially purposed for use in soils. The speciation of the heavy metals in the examined estuarine bottom sediments is dominated by strongly bonded mineral species, which account for 60–100% of the overall metal abundance. The preferred coprecipitation of metals with iron and manganese hydroxides seems to be responsible for this. Elevated abun- dances of heavy metals and organic carbon were measured in the estuaries of the Pechora River and, especially, of the Northern Dvina River. This allows the provisional inference to be made that these aquatic systems are anthropogenically polluted.