Environmental geochemistry of the copper slag old dump in the Middle Urals

Abstract

Relevance of the work. Wastes from mining and processing industries occupy vast areas and cause serious environmental damage. The research results will contribute to the development of biological reclamation of industrial areas and environmental monitoring. Purpose of the work: study of the geochemical features of soils and plants formed on old slags of the Polevsky copper smelter (Middle Urals). Methods of the study. We laid the plot in the relatively flat section of the base of the steep slope of the dump. Complex samples were taken at equal intervals on the transect and included blocks of technogenic soil along with growing plants. The material of the complex sample was divided into fractions by nature (soil, plants) and by size of fragments of copper smelting slag, dried to air-dry state and weighed. The chemical composition of the samples was determined by inductively coupled plasma mass spectrometry. Results. The man-made soil with a thickness of 10–15 cm has formed on the cast copper smelting slag old dump. More than a third of its mass is fine soil (particles less than 1 mm), which is a sorption geochemical barrier. The most elements concentration in fine soil is 1–2 orders of magnitude higher than their concentration in slag stone. Lead, cadmium, bismuth are especially effectively delayed. In the fine soil, the strongest excesses of the maximum permissible concentrations for all regulated elements have been established. It has been confirmed that under unlimited supply conditions of elements migration from slag, plant has an upper accumulation threshold. For the aboveground plant parts, the highest values of the biological absorption coefficient were found for selenium, potassium, calcium, and phosphorus. Conclusions. An environmental assessment of the Polevsky smelter (Middle Urals) old dump was carried out, the geochemical features of the soil and plants were investigated.