Heavy metal pollution assessment in the groundwater of the Meghna Ghat industrial area, Bangladesh, by using water pollution indices approach

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Heavy metal pollution in groundwater is a substantial environmental risk for Bangladesh. The Meghna Ghat industrial area in Bangladesh becomes a promising site for installing various industries for few decades. It was necessary to assess the heavy metal level in the groundwater of this area, and current study took the initiative. We collected 20 groundwater samples and tested pH, DO, TDS, EC, turbidity, COD, and DOC as well as four heavy metals (Cr, Cd, Pb, and Ni) to calculate four water quality indices, i.e., water quality index (WQI), degree of contamination (DC), heavy metal evaluation index (HEI), and heavy metal pollution index (HPI). Ni was too low to detect by the instrument, whereas the mean concentrations of Cr, Cd, and Pb were 0.07, 0.007, and 0.18 mg/L which exceeded the drinking water standards set by Bangladesh. According to the water quality indices, only 10% samples were good according to WQI; 30% and 15% samples were subjected to low level of pollution considering DC and HEI, respectively. Although according to HPI 35% samples were unsuitable for drinking, rest of the values were very close to characterize as unsuitable. Finally, we proposed two best-fitted models that can represent relationships between the metals and water quality indices. Water quality was comparatively better near the open spaces of the study area. The area needed to be under continuous monitoring for checking further pollution distribution.