WATER QUALITY ANALYSIS AND EVALUATION OF GANGASAGAR LAKE OF DARBHANGA DISTRICT IN BIHAR (INDIA)

The present study was conducted to evaluate the water quality for the purpose of the conservation of Gangasagar Lake of Darbhanga town of Bihar, India. Several physicochemical parameters such as pH, total dissolved solids (TDS), Dissolved oxygen (DO), Biochemical Oxygen Demand (BOD), total alkalinity, chloride content, total hardness were meticulously determined during various seasons for the year 2019. The TDS level exceeded     the permissible limit set by Bureau of Indian Standards. The dissolved oxygen was found to be the highest (7.8 mgl-1) and the lowest (6.4 mgl-1) in winter and summer season, respectively. Likewise, Biochemical oxygen demand was recorded to be the lowest (15.20 mgl-1) and the highest (25.67 mgl-1) in monsoon season and summer season, respectively. DO showed negative correlation (r=-0.71) with BOD. Water quality index was also estimated and its value was found in the range between 169.9 mgl-1 and 256.9 mgl-1 in monsoon and summer season, respectively which indicated greater impact of pollution in the lake. The result indicated the lake was getting polluted due to continuous discharge of certain junk materials, debris of construction materials and anthropogenic activities affecting the quality of aquatic life.