Geospatial analysis of fluoride contamination in groundwater of southeastern part of Anantapur district, Andhra Pradesh

Abstract

The occurrence of fluoride (F-) concentration in groundwater is mainly due to natural or geogenic pollution and the source of contamination is often unknown (Handa 1975a; Saxena and Ahmed 2002). Geogenic contamination of groundwater depends mainly on the geological setting of an area. As rain water infiltrates through soil and reaches the water table, it can dissolve partly certain component of bedrock. The F- content of groundwater can thus originate from the dissolution of fluorine-bearing minerals in the bed rock. In other words, bed rock mineralogy is a primary factor in general for the variations in F- content of groundwater (Chae et al. 2007; Raju et al. 2012). F- contamination of groundwater is a function of many factors such as availability and solubility of fluorine-bearing minerals, temperature, pH, concentration of calcium and bicarbonate ions in water, etc. (Chandra et al. 1981; Largent 1961). In contrast to anthropogenic pollution of surface water, geogenic contamination of groundwater is difficult to detect and even more difficult to control. The presence of excessive concentrations of F- in groundwater may persist for years, decades or even centuries and can reach the food system (Todd 1980). In recent years, there has been an increased interest in F- research because high concentration of F- in groundwater causes adverse impact on human health. In order to mitigate the excessive F- in groundwater, it is essential to determine and monitor the casual factors of enrichment of F- concentration in groundwater in time and space (Ahmed et al. 2002; Raju et al. 2009).