Hydrogeochemical evaluation of groundwater quality and seasonal variation in East Bokaro coalfield region, Jharkhand

Abstract

Groundwater samples collected from the East Bokaro coalfield of Jharkhand state, India during the dry and rainy seasons of the year 2012. Samples were analyzed for the assessment of groundwater quality in the study area. The results of the chemical analysis indicate that the pH values were found alkaline in nature during both the season. The major cations in groundwater was in the order of Na+>Ca2+>Mg2+>K+ during the dry season while Ca2+>Na+>Mg2+>K+ during the rainy season. The abundance of the major anions was of HCO3->SO42->Cl->NO3->F- did not change on the seasonal basis. The average NO3-concentration was exceeded the desirable limit for drinking water as per Indian standard in the rainy season. Silicate weathering was inferred to be a dominant process, controlling the groundwater chemistry in both seasons, with lesser contributions by carbonate weathering and ion exchange. Leaching of salts from the unsaturated zone also has a major impact on groundwater quality during the rainy season. The water quality data indicate that groundwater is generally suitable for irrigation. However, higher salinity and residual sodium carbonate values at some sites may limit groundwater use and therefore an adequate drainage and water management plan for the study area is required.