Assessment and regulation of the ecological state of soils in the impact zone of mining and metallurgical enterprises of Norilsk Nickel Company

An assessment of the ecological state of soils has been performed in the area of mining and metallurgical enterprises of Norilsk Nickel Company with respect to the level of soil contamination by heavy metals, the state of the vegetation, and the biological activity of the soils. The territory within 4 km from Norilsk is characterized by high concentrations of heavy metals, the absence of trees, and the disturbance of the organic matter mineralization. This zone corresponds to level 5 of the loss of environmental quality. At distances of 4–16 km from the city, the state of the environment corresponds to level 4, and, at distances of 16–25 km, to level 3. In the latter zone, the soils are characterized by increased concentrations of acid-soluble and mobile metal compounds, though the concentrations of water-soluble metal compounds do not exceed the maximum permissible levels; the soil microbiological activity is normalized. The state of the environment at a distance of 25 km from Norilsk is close to level 2. Soil contamination with heavy metals is accompanied by a rise in the portion of Cu, Ni, and Co compounds bound with amorphous iron oxides and hydroxides, as well as in the portion of their mobile forms.