Geochemical risks of diamond mining in Siberia

Geochemical risk is caused by the release of hazardous chemicals to the earth surface. Primary diamond deposits are located in difficult mining and geological conditions and represent natural geochemical anomalies associated with the mineral composition of rocks and groundwater, which contain a number of impurity elements with high toxic properties (Tl, Di, As, Cd, Hg), increased concentrations of heavy metals (Cu, Zn, Pb, Ti, V and others). The paper presents the physical-geographical and mining-geological conditions of the Sredne-Markhinsky diamondiferous region, where three large mining and processing divisions operate: Udachninsky, Aikhalsky and Nyurbinsky. In samples of soils, sediments, surface waters, drainage brines and vegetation were determined pH, organic matter (humus), total nitrogen, physical clay using potentiometric, photoelectric colorimetric, spectrophotometric methods and pipette method for particle size analysis. Gross and mobile forms of trace elements were determined by atomic absorption and atomic emission spectrometry. An assessment of the ecological and geochemical state of the study areas was carried out according to the indicator of total pollution (Zc), which is the sum of the excess of the concentration coefficients of chemical elements accumulating in anomalies. The zones of pollution and the greatest risk are localized. The groups of elements were identified that determined the natural and man-made anomalies.