Contamination of fluoride in groundwater and its effect on human health: a case study in hard rock aquifers of Siddipet, Telangana State, India

Hydrogeochemical investigation has been carried out in the granitic terrain of Siddipet area, Medak district, Telangana State, India with an aim to understand the distribution of fluoride in the groundwater and to understand the relationship of fluoride with other major ions, and also to identify the high fluoride-bearing groundwater zones. 104 groundwater samples were analyzed in the study area for fluoride and other major ions like calcium, magnesium, chloride, carbonate, bicarbonate, sodium, potassium, sulfate, and nitrate in addition to pH and electrical conductivity. The studies revealed that the concentration of fluoride in groundwater is ranging from 0.2 to 2.2 mg L−1 with a mean of 1.1 mg L−1. Nearly 22 % of groundwater has more than the permissible limit of fluoride (1.5 mg L−1), which is responsible for the endemic dental fluorosis in the area concerned. Geochemical classification of groundwater shows that Na–HCO3, Ca–Cl, and Ca–HCO3–Na are the dominant hydrochemical facies. Gibbs diagram shows rock–water interaction dominance and evaporation dominance, which are responsible for the change in the quality of water in the hard rock aquifer of the study area. The groundwater in villages and its environs are affected by fluoride contamination, and consequently majority of the population living in these villages suffer from dental fluorosis. Hence, they are advised to consume drinking water which has less than 1.5 mg L−1 fluoride to avoid further fluorosis risks. © 2016, The Author(s).