The article presents the results of a comprehensive survey of the trench at the Tuvakobalt plant, which contains waste from the hydrometallurgical processing of Cu-Co-Ni arsenide ores from the Khovu-Aksy deposit. Using electrical resistivity tomography, geoelectric maps and cross-sections were obtained, and a 3D model of the storage was constructed. A highly conductive (low-resistance) zone has been delineated in the central part of the trench – a substance with relatively higher moisture content than the surrounding side parts. The groundwater uncovered in the pit faces consists of mineralized solutions with a high arsenic content (up to 15 mg/l), which indicates active processes of interaction between seasonal waters and the trench material, as well as the accumulation of dissolved forms of metals and metalloids in the liquid phase of the highly conductive zone. This zone, which is narrow at the surface, widens towards the bottom of the trench and extends deeper than 40 m, which indicates the possibility of high-mineralized solutions entering the underground aquifers. Another pathway for the migration of pollutants is through emanations from the surface of the storage. A high concentration of chemical elements, including potentially toxic ones, enters the surface layer of the atmosphere with vapor-gas flows, as established by collecting and analyzing condensates. The forms of element migration in these flows were determined through laboratory experiments involving the capture and deposition of substances carried by the flows. The composition of the flows is primarily made up of amorphous organic compounds, with a small proportion of chlorides and sulfates; metals and arsenic are transported in the true gas flows in combination with organic ligands. The results of field and laboratory studies of the storage state indicate the presence of channels for water migration into underlying horizons, and under favorable conditions, a vapor-gas mixture rises from the surface, carrying metals and arsenic in a volatile, bioavailable form.
