Water quality evaluation in a rural stretch of Tezpur, Assam (India) using water quality index and correlation matrix

Abstract

Groundwater resources have a major role in ensuring livelihood security across the world, especially in economies that depends on agriculture. In India it is the major source of drinking water in both urban and rural and its importance cannot be over emphasized. It accounts for more than 85 % of the rural domestic water needs, and 50 % of the urban water needs (Ganeshkumar and Jaideep 2011). With an estimated use of 230 km3 of groundwater every year, i.e. more than a quarter of the global level, India is the largest user of groundwater in the world. At present apart from depletion of groundwater level, India is also facing problems regarding the increments of pollutant concentration present in it. In the North Eastern region of India, natural springs and dug wells are the only cost effective viable means of fulfilling the domestic needs for present population. Information on groundwater quality of northeast India is scanty (Suryawanshi et al. 2004). It has been reported that the concentration of fluoride (F-), and iron [Fe(II)] in the groundwater is much higher than the permissible limits of drinking water at different areas of Assam (Sushella 2001). Fluoride in the groundwater of Assam has been reported in the range of 5–23 mg/L (Meenakshi and Maheshwari 2006) and iron in the range of 1–25 mg/L (Das et al. 2003; Mahanta et al. 2004). The permissible limit in drinking water is 1–1.5 mg/L for fluoride and 0.3 mg/L for iron (IS 10500 1991; WHO 1993). The iron present in the groundwater causes visible colouration to the water, but fluoride doesn’t impart any colour to the water. Therefore the quality of drinking water is of vital importance for human being, though most consumers are unaware of the various pollutants present in the groundwater.