Harmful metals concentration in sediments and fishes of biologically important estuary, Bay of Bengal

Study on the accumulation level of heavy metals was conducted on sediment and fishes from estuaries of Bay of Bengal. Heavy metals were determined by using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and the results were compared to permissible limits of WHO/USEPA. The accumulation patterns of Fe and Cd were found predominantly in all samples tested when correlated with other metals. It was found that the concentration of metals such as Cd (3.90 ± 0.25 μg/g), Cr (0.44 ± 0.05 μg/g), Ni (0.33 ± 0.01 μg/g), and Mn (1.1 ± 0.11 μg/g) were exceeding the permissible limit, whereas Fe, Co, Pb, and Zn were found within the limit of WHO/USEPA at station 1. In station 2, Cd (16.5 ± 0.4 μg/g), Mn (0.67 ± 0.11 μg/g), and Cr (0.80 ± 0.01 μg/g) were exceeding the permissible limit, whereas Fe, Co, Pb, Ni, and Zn were found within the limit. This study emphasizes that Cd and Mn levels in both stations, are far higher than the acceptable values set by WHO/USEPA and may therefore present human health hazards. It is therefore mandatory to carry out extensive research to evaluate the possible environmental risk factors in the vicinity of both estuaries with respect to heavy metals.