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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.

Natural radioactivity concentrations in recent alluvial soils from swampy areas and Tertiary rocks from Jaintiapur were measured using gamma-ray spectrometer equipped with HPGe detector. The average radioactivity concentration of 226 Ra, 232 Th and 40 K were 47 ± 6, 64 ± 5 and 762 ± 40 Bqkg −1 in soils, whereas, 25 ± 2, 37 ± 4 and 884 ± 41 Bqkg −1 in rock samples, respectively. Average radioactivity concentrations of studied soil and rock samples exceeded the world average except 226 Ra for rocks. Radio-elemental ratios suggest that an oxic depositional environment with low uranium and high thorium content. Regarding radiological hazard indices, radium equivalent activities (Ra eq ), external hazard index ( H ex ) and internal hazard index ( H in ) was found to be below the world permissible limits. Whereas, absorbed dose rate (D), and annual effective dose equivalent (AEDE) averages exceeded the world admissible values. Statistical studies show that radioactivity for 226 Ra and 232 Th linked to a source enriched in radioactive minerals and 40 K related to a different sources high in K enriched minerals.

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