Evaluation of water quality index for drinking purposes of river Subernarekha in Singhbhum District

An attempt has been made to develop water quality index (WQI), using six water quality parameters Dissolved oxygen (DO), Biochemical oxygen Demand (BOD), Most Probable Number (MPN), Turbidity, Total Dissolved Solids (TDS) and pH measured at five different stations along the river basin from November 2006 to November 2007. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method was used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Subernarekha varied from Excellent to Marginal range by Bhargava WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites,high anthropogenic activities and and direct discharge of industrial effluent.