Heavy metals in the Ulyuk-Bar gold deposit soils (Southern Urals)

The assessment of the leptosols composition and the increased concentrations of heavy metals in them at the Ulyuk-Bar gold deposit was carried out. The mineral components of the soils are represented by quartz, illite, kaolinite, goethite and iron-manganese nodules. The minerals concentrating of As, which represents the greatest potential danger in the deposit and exceeding (maximum allowable concentration) MAC by 159.5 times, are goethite, and rarely kaolinite. The chemical composition of soils is close to that of soil-forming sandstones. In general, in the process of soil formation, accumulation or minor removal occurs for most elements. The contents of As, Co, Pb, K, Zr, Cu, Mn, Zn, Ni exceed сlark for continental soils. The degree of mobility for soil elements decreases in the range Sb (46.25) – Ca (36.84) – S (31.48) – Sr (27.91) – Mn (15.38) – Pb (8.84) – Ba (5.41) – Mg (2.88) – Zn (2.70) – Ni (1.70) – P (1.55) – Cu (0.76) – Cr (0.45) – Si (0.42) – K (0.39) – Na (0.20) – Al (0.07) – Fe (0.05) – Co (0.05); Ti, V, Zr, As are immobile. The mobile forms of Mn are 2.22 times higher, the gross contents of S are 3.71 times higher than the MAC. Concentrations of heavy metals such as Fe, Mn, Sr, Ba and Cr in soil ammonium acetate extracts increase with increasing alkalinity of the salt extract, and Zn, Cu, Pb and Sb − acidity. To prevent the mobility of heavy metals to an environmentally sustainable level, an effective reclamation program should include a set of methods for selecting the optimal ratios of chemicals added to the soil.