Hydrogeochemistry and heavy metal contamination in groundwaters of Dhaka metropolitan city, Bangladesh: Assessment of human health impact

Abstract

A total of 47 groundwater samples were collected in Dhaka metropolitan city, Bangladesh to determine the drinking quality in terms of pH, EC, TDS, hardness, CO3, HCO3, Cl, SO4, PO4, Ca, Mg, Na, K, Fe, Mn, Cu, Zn, Cr, Pb and As, and to assess their impact on human health. Groundwater samples of the study area were predominantly influenced by the Ca-Mg-HCO3 hydrochemical facies. According to WHO guidelines, 100 and 6.4% of groundwater samples were rated as unsuitable for drinking usages due to higher contents of Pb and As, respectively. All water quality indices showed highly significant positive correlations with each other and heavy metals. The contribution of heavy metals to the non-carcinogenic health risk for both adult and child was in the sequence of Pb > As > Mn > Cr > Cu > Fe > Zn. The spatial distribution of hazard index (HI) values revealed that the city's central-western part is a more vulnerable zone for public health issues.

Keywords

• Drinking quality
• Water quality indices
• Piper diagram
• Hazard quotient
• Hazard index