The development of coal deposits is accompanied by negative environmental changes. In the territory of the Kizel coal basin (Perm Region, Russia), the problem of contamination of water sources by acid mine waters and runoff from rock dumps is particularly acute. Mine waters are acidic (pH 2–3), with high mineralization (up to 25 g/L) and significant content of sulfate ions, iron, aluminum, manganese, toxic trace elements (As, Co, Ni, Pb and Zn). They are formed as a result of the interaction of underground waters from flooded mines of the Kizel basin with coal and rocks of dumps with high sulfur content (15%). Uncontrolled inflow of mine water into rivers (about 22 million m3 annually) leads to significant amounts of iron and aluminum hydroxide precipitation. These precipitations are in active interaction with river water, polluting the rivers tens of kilometers downstream and are entering the Kama reservoir. Studies of alluvial precipitation can be considered as a method of control and predictors of technogenic water pollution. The mineral composition of river sediments was studied with the application of different methods, including studies of sand-gravel and silty-clayey sediments. The sandy-gravel grains in the bottom load are mainly composed by natural minerals and are represented by a significant number of particles of coal dumps, slags and magnetic spherules. The silty-clayey material, mixed with natural minerals, contains a significant number of amorphous phases with a predominance of iron-rich substances, which may actively concentrate toxic elements. The presence of jarosite, goethite, basaluminite, lepidorocite and copiapite in silty-clayey sediments are indicators of the influence of mine waters.
In terms of anthropogenic impact of mining and processing enterprises, the adjacent territories are contaminated by upstream tailings dams. The contamination is developed by active seepage of liquid waste through the body of the dams. The authors have analyzed water balance at the Kachkanar Mining and Processing Plant tailings dump (Russia, Ural Region). The company develops vanadium-containing titanium-magnetite iron ores with low ore (15%). This, along with high productivity, has determined the formation of a large number of tailings and significant amount of wastewater. The purpose of the studies is to substantiate the need to manage the seepage discharge process by means of enclosing dams to ensure environmentally safe operation of the tailings dump. The research objectives included field measurements of seepage volumes, their evaluation by computational methods and analysis of anthropogenic geochemical load on natural waters. The obtained results show an increase in seepage discharge volume from 41.91 million m3 (in 2017) to 81.44 million m3 (in 2026) as the height of the dams increases. These losses will lead to water shortages in the enterprise’s water recycling system. Calculation of pollutants in wastewater with the exception of natural component showed the leading role of technogenic factor in the content of Ti (up to 84%), V (up to 96%), Co (up to 86%) and Mo (up to 93%). Increasing the volume of seepage discharge will lead to an increase in natural water pollution within the area. Ecologically efficient management of the enterprise’s water balance is ensured by the use of tailings thickening technology and implementation of closed water supply systems.
The Kosva Bay is permanently affected by acid mine drainage (AMD) from Kizel Coal Basin in the Perm Krai of Russia. This discharge is released in the middle part of the Kosva River from the abandoned mines. This study investigates the current trace element (TE) concentrations for Zn, Cu, Pb, Ni, Cr, Cd, As, and Hg and the mineral composition, major oxides, grain size of sediments, and acute toxicity using two test organisms within the site of AMD downstream from the Kosva River and up to the Kosva Bay of Kama Reservoir. The objectives of this study were to analyze the quality of sediment and level pollution of Kosva Bay using pollution and ecotoxicological indices. The environmental indices, namely the contamination factor (CF), the geoaccumulation index (Igeo), and the potential ecological risk factor ( indicate contamination by Cr and Pb in sediments at the site of AMD, with the highest values for Cr, Cu, and As in the Kosva Bay sediments downstream of abandoned coal mines. The results of Igeo and CF average values in bay of sediments showed different degrees of contamination, from moderate contamination to considerable contamination, respectively. According to the potential ecological risk index (RI) values, the Kosva Bay sediments exhibited low to moderate risk, and As and Cd have the highest contribution rate. According to LAWA and the Polish geochemical classification of sediments, sediments of the bay correspond to the highest levels (IV–III classes) for Cr, Ni, and Hg. Based on the SQGC, Hg, Cd, Cr, and Ni are the most probable for resulting in adverse effects on aquatic organisms in this study. The results of this study indicate that complex pollution and ecotoxicological indices must be supported by ecotoxicologal tests. High precipitation totals, low evaporation rates, and flow regulation stream by the Shirokovsky Reservoir located upstream from abandoned coal mines provide significant fluctuations in streamflow, which is probably the most important factor controlling the distribution and mobility of TE in the studied sediments.
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