Heavy Metals and Arsenic in Fluvisols of the Norilsk Industrial District

The research is aimed at the pattern of heavy metal and arsenic distribution and assessment of the ecological state of Fluvisols in the watercourses with the headstreams situated within the area of the largest mining and metallurgy center in the Russian Arctic, the Norilsk industrial district (NID). The bulk content of As, Pb, Zn, Cd, Cu, Ni, Co, and Cr and the concentrations of their mobile species are determined in the rhizosphere (0–20 cm). Their concentrations are severalfold higher than the clarke, approximate, and maximum permissible concentrations. Note that the share of mobile forms relative to the bulk content does not exceed 13.5% and decreases in the following order: Cd > Cr > Ni > Cu > Co > Zn > Pb. The concentrations and shares of mobile species of chemical elements in soils increase downstream in each of studied watercourses. Single-factor (Kc/PI and Igeo) and complex (Zc, NPI, PLI, and PERI) soil pollution indices are calculated and analyzed. The studied objects are grouped according to the degree of pollution using cluster analysis and principal component method; the objects with prevalent geogenic accumulation of chemical elements are identified. According to the results of the study, the regional background values of bulk content and concentrations of mobile forms of heavy metals in Fluvisols of the NID are proposed. The identified specific features of floodplain landscapes increase the risk of pollution spreading over large areas, while the use of appropriate regional standards can improve the accuracy of soil ecological assessments and the efficiency of environmental protection measures.