Impact of Kara-Keche lignite mining on the Kara-Keche River water composition and properties

Abstract

On the evidence of the earlier research findings, as well as the full-scale and lab-scale test data of 2019–2020, this article describes the ecological situation at Kara-Keche lignite field being developed by five mining companies in the Jumgal district of the Naryn Region in the Kyrgyz Republic. It is found that the field development proceeds with insufficient adherence to legal documents and has a considerable adverse influence on the environment and water bodies. Many large-volume refuse dumps have no isolation from natural water bodies, which ends with acute pollution of the latter. Contamination of local rivers exists both below the coal mining sites and above them, because of winnowing of coal dust. The river water has the increased pollution indexes—the coliform indexes are 55–70, even in winter, and in summer, these indexes reach a few thousands units. The solid residue, suspended matters, chemical oxygen demand as well as the carbonate and total hardnesses at the points below the major pollution sources as against the averaged values at the points located above the pollution sources have very high values: 14% for the chemical oxygen demand; 43 for the dry residue; 86 and 35 for the carbonate and total hardness, respectively; 108 % for the suspended matter. The concentrations of all macro elements–cations (and anions) grow at a relatively small distance (~5 km) below the major pollution sources: by 11.2 % for sodium; 22 % for potassium 42.2 % for calcium and 79.9 % for magnesium. The analyses revealed no one of 22 trace elements (Ag, As, B, Be, Cd, Co, Cr, Cu, Hg, Mo, Ni, P, Pb, S, Sb, Se, Sn, Ti, U, V, W, Zn) in the Kara-Keche river water, supposedly, because of low sensitivity of the spectrometer. The concentrations of some trace elements (aluminum and barium) are noticeably lower (almost by 2 times) below the major pollution sources. The concentrations of the other trace elements at the points below the major pollution sources are higher than the averaged values at the points above the pollution sources: by 2.2 % for silicon; by 28.3 % for iron; by 76 % for strontium and by 83.4 % for lithium.