Impact of coal mining activities on the water quality: A case study of Jharia Coalfield, Dhanbad, India

Coal mining is a major industrial activity that significantly contributes to India's economic growth, particularly in the Jharia Coalfield area of Dhanbad, Jharkhand. However, the environmental impact of such activity, especially on groundwater and surface water quality, remains a matter of serious concern. In this study, we conducted a hydrogeochemical analysis of water samples collected from 15 locations, which include active collieries, washery units, overburden dumps, and the Damodar River. Various physicochemical parameters, major cations, anions, and heavy/toxic metals were assessed. Results show increased total dissolved solids (TDS) in all samples except Damodar River water sample, hardness in 13 samples, and BOD levels in 10 samples, all of which surpass the permissible limits set by WHO. This makes the water unsafe for direct drinking. Contamination by aluminium and cadmium was observed (all samples exceeded the WHO permissible limit), while chromium and nickel levels marginally exceeded safe limits. Gibbs diagrams and correlation matrices identified rock weathering, coal washery discharge, and acid mine drainage as the primary factors influencing water chemistry. The above results highlight the need for ongoing monitoring and remediation techniques as well as the significant decline in water quality in mining zones. This comprehensive assessment further underscores the urgent need for monitoring of water quality in coal mining areas, emphasising the balance between energy security and environmental health.