Evaluation of aqueous geochemistry of fluoride enriched groundwater: A case study of the Patan district, Gujarat, Western India (original) (raw)

High fluoride (F −) groundwater causes fluorosis which might at severe stages lead to deformation of bones, bilateral lameness. The concentration of F − ranged from 0.4 to 4.8 mg/L. This study suggests that high HCO 3 − and Na + in alkaline medium along with water-rock interaction plays important role in enrichment of F − in groundwater. Na-HCO 3 is the dominant water type followed by Ca-HCO 3 suggesting dominance of Na + , Ca 2+ and HCO 3 − ions in groundwater. Factor analysis of water quality parameters suggests that four principal components account for 74.66% of total variance in the dataset. Factor 1 shows higher positive loading for pH, HCO 3 − negative loading for F − , Ca 2+ , SO 4 2− depicting ion-exchange and HCO 3 dominant water type responsible for F enrichment in groundwater. Saturation index for selected minerals suggests that most of the samples are oversaturated with calcite and undersaturated with fluorite. Calcite precipitation leads to the removal of Ca 2+ from solution thus allowing more fluorite to dissolve. These released Ca 2+ ions combine with CO 3 2− ions to further enhance the precipitation of CaCO 3 .