Deleneation of groundwater quality in the presence of fluoride in selected villages of Simlapal block, Bankura district, West Bengal, India

Fluoride contamination and other physicochemical parameters in groundwater of Simlapal block of Bankura district were investigated. A total of 50 deep tube well (DTW) samples were collected from 18 villages of Simlapal. The higher concentration of iron values was recorded, 9.40 mg/L with an average value of 2.11 mg/L. Drastically, 58 % of water samples exceed the permissible limit of 1.5 mg/L (Guidelines for drinking water quality, World Health Organization, Geneva, 2004). Spatial distribution of F⁻ (Guidelines for drinking water quality, World Health Organization, Geneva, 2004) concentration classes is represented by the simple Inverse Distance Weighting (IDW) interpolation method. The affinity between the pH and F⁻ in groundwater suggests the dissolution of fluoride-bearing minerals in groundwater. Furthermore, the pH has a good positive correlation with HCO₃ ⁻ (r = 0.224). This indicates a prevailing condition of alkalinity (caused by HCO₃ only here) in the groundwater, which promotes a mineral dissolution. The F⁻ shows a significant positive correlation with pH (r = 0.313, p < 0.05) and HCO₃ ⁻ (r = 0.224), while it has a negative correlation with Ca and Mg ions (r = −0.225 and −0.226). PCA accounts for 74.21 % of the variability for the first four components. F1 values have high loading (32.71 %), second component (F2) exhibits 19.98 %, third component (F3) shows 12.74 %, and fourth component (F4) shows only 8.72 % of the total variability to justify the significant correlation between chemical constituents. In terms of quality of water, sodium adsorption rate (SAR) showed that all the samples are from the group of excellent to good. With respect to permeability, sodium percentages show that 18 % are permissible but doubtful and 2 % are unsuitable for irrigation purposes.