The results of a survey of the mineral phases of the sediments of the Lake Nudjavr contaminated by the sewage waters of the Severonickel Company using a scanning electron microscope are presented. The samples show the presence of mineral grains of round shape, containing Ni, Cu, Co, Cr, Fe. In a number of cases, sulfur nickel (Ni3S2), nickel (NiO) and iron (FeO) oxides were identified in the samples. Other findings are probably particles of matte and a mixture of oxides of Fe, Ni, Cu, Co and other elements. The shape and composition of the particles found gives reason to indicate their technogenic origin.
Key words: mineral phases, lacustrine sediments, heavy metals