Groundwater Quality Evaluation with Special reference to Fluoride and Nitrate Pollution in Uravakonda, Anantapur District, Andhra Pradesh– a case Study

Abstract

Water is essential natural resource for sustaining life and environment which we have always thought to be available in abundance and free gift of nature. Though ground water is the major drinking water source, deterioration in its quality is going unchecked. In such agro-economy based rural areas, the nitrate contamination is rampant and much attention has not been drawn towards this anthropogenic pollution. In the study area ground water samples from different hydro geological set-up have been collected during the pre and post monsoon seasons and analyzed for the major ions such as Ca²⁺, Mg²⁺, Na⁺, K⁺, CO₃^2-, HCO₃^-, Cl^-, SO₄^2-, NO₃^- and F^-.The study revealed that 95% of the samples were found to be unsuitable for drinking purposes in the pre-monsoon season and 90% in the post monsoon due to excess nitrate (>45 mg/l) content in the ground water. Intense agriculture practices, improper sewerage and organic waste disposal methods were observed to contribute nitrate to the shallow and moderately deep aquifers. Fluoride concentrations in groundwater samples were determined in the study area. Fluoride concentrations in groundwater samples of these villages varied between 0.5 mg/l and 7.2 mg/l. Majority of the samples are exceeding the permissible limit of fluoride 1.5 mg/l [1]. Probable sources of fluoride are weathering and leaching of fluoride bearing minerals under the alkaline environment. Further the concentration of fluoride is aided by high rate of evaporation, longer residence time of waters in the aquifer zone, intensive and long term irrigation. Dental and skeletal fluorosis and deformation of bones in children as well as adults were observed in the study area indicating the health impact of fluoride in groundwater.