Characterization, variations, fluxes, and sources of contaminants in coal mine water of Korba basin, Chhattisgarh, India

Several million tons of coal are extracted which discharge the contaminated mineral water into the environment in the coal mines located in the Korba basin (Chhattisgarh, India) chosen as the study area. The aim of this work is to describe: (i) the physico-chemical characteristics (pH, EC, TDS, DO, RP, CC (carbonate carbon), OC (organic carbon) F-, Cl-, NO3-, SO42-, SiO44-, PO43-, Na+, K+, Mg2+, Ca2+, Al, As, Sb, Fe, Mn, Zn, Cd, Pb, and Hg) of the coal mine water samples, (ii) spatial, seasonal (i.e. PrM (pre-monsoon), M (monsoon) and PtM (post monsoon) and temporal (over the period of 2012-2017) variations, (iii) sources of contaminants from fourteen coal mines, (iv) suitability of the water for drinking and other uses, and (v) health impact of the mine water in view of developing remedial approaches.The mine water is neutral in nature with high TDS (total dissolved solid) values ranging from 620 to 13711 mg L-1 due to mainly high carbon content. The concertation of all species lies between 519-11432 mg L-1 with maximum value of OC. The most dominating species were OC, CC, Cl-, NO3-, SO42-, Na, and Ca. Species, that is, F-, OC, Al, Fe, As, Sb, Cd, Pb, and Hg occurred beyond their limits. Their higher concentration in the PtM is observed. Water quality index (WQI) values ranged from 17.52 to 95.68 in the PtM period. 42.85%, 21.42%, and 7.14% of water samples represent "excellent water", "good water" and "poor water" respectively in the PtM period. In addition, the fertilizer and trace element concentrations in the water samples were compared with the limit values determined for usability as drinking water. Accordingly, it was concluded that it is not suitable for use as drinking water in terms of TDS, F-, and NO3- concentrations. In addition, AsT (total arsenic), F- and NO3- pollutants were detected in the water samples, and it was observed that F- and NO3- ions did not have a carcinogenic effect. A health risk assessment of As has been made, and it is found that adults and children have a low risk of developing cancer from the exposure. However, arsenic has high non-carcinogenic and potentially harmful effects.