Heavy Metals Distribution and Contamination in Groundwater of the South Eastern Coastal Area of Bangladesh

Abstract

Groundwater provides the largest source of usable water storage in Bangladesh. Groundwater samples have been analyzed for Fe, Mn, Zn, Ni, Cr, Cu, Cd, Pb, and Co using atomic absorption spectrophotometer to evaluate the heavy metal distribution and contamination level at the southeastern coastal area of Bangladesh. Heavy metals in water samples are in the range of Fe (490–4710 µg/L), Mn (13–1970 µg/L), Zn (70–550 µg/L), Ni (42–255 µg/L), Cr (25–133 µg/L), Cu (34–95 µg/L), Cd (7–26 µg/L), Pb (0–20 µg/L), and Co (43–141 µg/L). The mean concentration of Cr, Cd, Fe, Mn, and Ni exceeded the Bangladesh standards for drinking water. Application of Pearson correlation, principal component analysis (PCA), cluster analysis (CA) and hierarchical cluster analysis (HCA) indicate that groundwater of the study area are influenced by both geogenic and anthropogenic sources of the heavy metals. Heavy metal evaluation index (HEI), degree of contamination (C_d) and heavy metal pollution index (HPI) are employed to evaluate the overall pollution level of groundwater estimating 40, 27 and 60% of samples respectively and exhibit the medium degree of pollution.