Assessing the utilization potential of pumped-out minewater for potability in the water-stressed coal mining region of Jharia, India: a quantitative, qualitative and probabilistic health risk assessment

Extensive mining operations coupled by a steady rise in local population have rendered the Jharia Coalfield water-stressed with limited access to potable water, risking the outbreak of waterborne diseases from prolonged inaccessibility. A quantitative assessment was done to utilize the pumped-out minewater by harvesting it in mine voids underlying the coalfield, preventing further loss as surface runoff. A total void volume of 13 billion gallons was identified and mapped using Digital Elevation Model-CARTOSAT. Analysis of minewater in the region revealed variations in hydrochemical parameters, indicating heterogeneity in the underlying hydrosystems of the region due to the synergistic influence of geological formations and anthropogenic processes on the region's water chemistry. Qualitative evaluation of the hydrochemical parameters of minewater using Heavy Metal Pollution Index (HPI) and a novel Integrated Water Quality Index (IWQI) revealed mostly poor minewater quality across the region, barring Shatabdi (IWQI-1.97; HPI-25.30). A comprehensive quantitative and qualitative assessment of utilizing harvested minewater for potability in a water-stressed region while appraising its probabilistic risk to the local populace formed the theme of this study. Monte Carlo simulation-based health risk assessment revealed that children were more prone to non-carcinogenic risk from As and Mn, with hazard index (HI) values reaching up to 5.33 in some locations. The contribution of carcinogenic risk from the trace/heavy metals were in the order Ni > As > Cr > Pb > Cd and exceeded the maximum acceptable level (10(-6)) in majority of the locations, warranting continual monitoring and appropriate treatment to ameliorate health risks.