[Summary translation prepared by Business & Human Rights Centre]

Assessment of the hazard of polymetallic contamination of mountain–meadow chernozem-like soils from the tailings storage facility of the Urupsky mining and processing plant, September 4, 2025

The Urupsky Mining and Processing Plant is the largest copper pyrite mining and processing enterprise in southern Russia, whose waste contains high concentrations of heavy metals. The conducted study made it possible, for the first time, to determine the zone of negative impact of the Urupsky plant’s tailings storage facility on the surrounding area, including the degree of contamination, priority pollutants, the distance from the tailings facility affected by pollution, and the distance at which changes in the biological properties of soils occur.

An assessment was carried out of the degree of contamination of the upper 0–10 cm layer of mountain–meadow chernozem-like soil (Mollic Leptosol) by 48 potentially toxic elements (PTEs), depending on distance from the tailings storage facility, as well as the impact of contamination on soil biological properties. Priority pollutants responsible for the highest levels of soil contamination were identified: at a distance of 5 m from the tailings facility, soil concentrations of Ag were 63 times higher than background levels; Sb 25 times higher; Hg 23; Cu 19; Te 19; Zn 14; Cd 14; As 13; Mo 12; and Pb 6 times higher. At the same time, at a distance of 300–400 m from the tailings facility, soil contamination was no longer observed.

Negative effects of the tailings storage facility on catalase and dehydrogenase activity, total bacterial counts, and root length of radish seedlings were not observed beyond 100 m from the facility; effects on urease activity, germination rate, germination energy and speed, and shoot length of radish seedlings were absent beyond 200 m; effects on invertase activity beyond 300 m; and effects on the abundance of Azotobacter bacteria beyond 400 m. The degree of decline in biological indicators of soil condition correlates with the content of PTEs in the soil.