MD. REZAUL HAQUE, JASIM UDDIN AHMAD, MD. DIDARUL ALAM CHOWDHURV, MD. KAWSER AHMED AND MD. SAFIUR RAHMAN
Abstract
Concentrations of Cu, Zn, Fe, Pb, Cd, Cr and Ni were determined from sediment of the Rivers and Estuaries of the Sundarban mangrove forest located in the southwest coastal region of Bangladesh. At seven different locations the concentration of Cu, Zn, Fe, Pb, Cd, Cr and Ni seasonally varied from 9.91 to 26.64, 26.22 to 53.39, 1198 to 12984, 11.88 to 45.53, 0.093 to 0.784, 13.4 to 44.65 and 9.05 to 33.81 i.tg.g-1 respectively. Fe was the most abundant metal found and almost at all stations the higher concentration of heavy metals were observed during summer except Cu and Pb. The concentration of Fe, Cr, Pb, Cd and Ni were exceeded the certified values. Concentration of Cd and Ni in sediment were found higher in the Sea and Hironpoint which might be due to the fact that the numerous rivers and their tributaries that cress-cross Sundarban carry pollutants from the neighbouring area. This implies that with flood tides in the Sundarbans there is a possibility that pollutant discharged from the Hoogly estuary enters into the sea could be carried far into the Sundarban. Sundarban mangrove ecosystem become a sump for pollutants because the normal structure and circulation of currents in Bay of Bengal tend to prevent the mixing of these shallow waters with the rest of the ocean.