Geological Environment Role in the Formation of Hydrogeoecological Conditions within Large Industrial Zones

Abstract

© 2020 Published under licence by IOP Publishing Ltd. Natural and man-made conditions of the Nizhnekamskaya industrial zone are discussed in the article. This zone includes large petrochemical and oil refineries, PJSC «Nizhnekamskneftekhim» is one of the largest companies in Europe. The article shows that significant changes in the composition of natural waters are manifested within the territory of a large operating surface landfill for industrial waste and in its vicinity. Here, the salinity of underground water can reach 12 g/l, and the concentration of petroleum products and phenols, which are characteristic pollutants, reaches 982 and 14 mg/l. Within the industrial site, underground water salinity reaches 1.25 g/l, their hardness is 18 mmol/l, and permanganate index is 17.3 mgO/l. The intensity of pollution of natural waters decreases with increasing distance from the boundaries of industrial zones. There are no signs of pollution of natural waters at a distance of 1.0-1.5 km from the landfill. The composition of natural waters has not changed over the past 40 years outside the industrial zone. Here, HCO3/Ca and HCO3/Mg-Ca are developed; waters with mineralization up to 0.5-0.6 g/l and total hardness up to 7 mmol/l are favorable for drinking. Natural water pollution is local, since the geological environment has high buffer properties. The nature of the geological section, consisting mainly of clay rocks, the favorable quality of precipitation at their rate of 550 mm/year determine these properties. The predominant type of pollutants, represented mainly by organic substances (petroleum products, phenols, etc.), which are subjected to chemical and biological degradation, also determine these properties. In addition, vertical hydrogeochemical zonality plays an important role. It changes with an increase in the depth of the HCO3/Ca waters of the waters of HCO3/Na composition. At the same time, the salinity of underground water is in the range of 430-600 mg/l, and the hardness decreases from 6.4-7.3 to 0.5-2.3 mmol/l. This determines the possibility of obtaining potable quality water in any part of the industrial zone, where the optimal depths of wells' filters are 140-160 m.