Assessment of groundwater quality of two selected villages of Nawada district of Bihar using water quality index

Abstract

Unplanned discarding of industrial effluent, sewage, domestic and industrial solid waste, unwise use of insecticides, herbicides, pesticides, and fertilizer in agriculture are the major causes of groundwater quality reduction. In the present paper groundwater quality of the two selected village of Rajauli subdivision of Nawada district of Bihar was assessed using water quality index (WQI). The samples were figured out for the parameters such as temperature, pH, electrical conductivity (EC), total dissolved solids (TDS), alkalinity, dissolved oxygen (DO), total hardness (TH), chloride, calcium (Ca), magnesium (Mg), biochemical oxygen demand (BOD), and fluoride. All the parameters were found below the standard limits of Bureau of Indian Standard (BIS, 2012) except total hardness (328.1mg/l to 346.6mg/l), calcium (105.3mg/l to 122.6mg/l), magnesium (46.1mg/l to 55.7mg/l) and fluoride (4.8 to 4.9mg/l). Fluoride was observed more than 3 times than the standard permissible limit (1.5mg/l). Water quality index (WQI) was also applied on the obtained data to make it easy to understand. Based on WQI (including the fluoride), all the four sites fall in unfit for drinking category (250.79, 258.78, 281.78, 247.30) and in poor to very poor category (80.23, 88.19, 88.59, 64.60) excluding the fluoride from WQI calculation. Both the values of WQI shows that fluoride alone is not responsible for the degraded quality of water but other high concentration of salts is also responsible.