ASSESSMENT OF FLUORIDE DISTRIBUTION AND IONIC BALANCE IN GROUND WATER OF SIRUGUPPA TALUK, BALLARI DISTRICT, KARNATAKA, INDIA – A CASE STUDY

A total, 44 different ground-water samples collected in Siruguppai taluk in of Ballari district, Karnataka, India to appraise the distribution of Fluoride. pH of collected groundwater are shown alkaline in nature and ranged between 7.4 and 8.5 with a mean value of 8.0. Fluoride content ranged between 0.16 to 2.76 mg/L in ground water samples, with minimum value 0.16 mg/L (SWG38) and maximum value 2.76 mg/L (SWG17). 64% of samples indicated fluoride content below 1.0 mg/ L and 20% samples indicated fluoride content in between 1.0 and 2.0 mg/L. Followed by 16% of the samples showed fluoride content ranges above 2.0 mg/L. The public from villagers have been used high fluoride-bearing groundwater for drinking prolonged period and suffering from fluorosis. Analytical values also predict that, occurrence of minerals like apatite, fluorspar, topaz and mica get processed naturally and releases fluoride into the lithosphere and percolates into ground water. The present study also helps find out a suitable adsorbent for removal of Fluoride in ground water. However, with respect to chemistry of water, the cation and anion balance of all the 44 groundwater samples were inside the recognized limit of ± 10%. The fluoride content is maximum in Na+– HCO3−- type and low in Ca2+–HCO3−. type groundwater in the Siruguppa Taluk. Furthermore, F− shown a significant positive correlation with pH, EC, TDS, Ca2+, HCO3- and negative correlation with Mg2+ and NO3−, which shows that the alkaline condition of water is the key role for leachate forming of fluoride-bearing minerals. Gibbs chart shows all groundwater values are fall under dominance of rock weathering group with a tendency towards the evaporation dominance class. Hence, interaction of rock–water is the pioneer cause of raised fluoride in the groundwater of the study area. Furthermore, the study showed no such substantial relation present between F− and NO3− these variables are further process to groundwater from different sources, F− from geological minerals and NO3− from manmade activities.