Vestnik MGTU (Mar 2019)
Lakes hydrochemistry in the zone of influence of iron-mining industry waste waters
Abstract
To assess the current ecological state, a study has been conducted on the chemical composition of the lakes' waters which to varying degrees are influenced by the effluents of Olkon JSC (the town of Olenegorsk, the Murmansk region) mined and processed iron ores. The composition of the water of nearby reservoirs has undergone significant changes with the beginning of the activities of Olkon JSC. Mineralization (up to 100 mg/l) and pH values (up to 7.6) of the water of the studied lakes have increased. The qualitative composition of the water of these lakes also changed – the water class has changed from bicarbonate to sulphate. The biotites that make up the gneisses to which the ore bodies of ferruginous quartzites are confined are the main sources of cations K+ and Mg2+, and amphiboles – Ca2+ and Na+. Therefore, the increase in the content of basic ions and the mineralization of lake water is caused by the inflow of filtration water from tailing and waste dumps of Olkon JSC. The advanced content of the nitrogen group compounds (nitrate ion, ammonium ion and total nitrogen) has been recorded in the lakes' water. This increase is associated with the use of explosives containing nitrogen compounds during drilling and blasting operations for the extraction of iron ores. The content of NO3– in water of some lakes is higher than the content of the basic ions Na+, K+, Cl– in terms of equivalent concentrate ion. The flow of pollutants in the composition of wastewater has led to the suppression of biological activity and a decrease in the content of organic matter in the lake water. The highest levels of Ni, Cu, Co, Al, and Sr are recorded in lakes that receive iron ore production effluent. At the same time Fe concentrations are the smallest, which is associated with the pH value increase in the lake water (which decreases the solubility of Fe ions), and with the decrease in the content of organic material, as far as Fe in the lake waters of the Murmansk region is found mainly in the composition of organo-mineral compounds
Keywords
