Dynamics of Cadmium and Lead in Some Soils of Chittagong, Bangladesh

Total, 1N NH 4 OAc and 0.1N HCl extractable Cd and Pb were determined in soils of four sites of Chittagong City contaminated by city sewage (Site-I), tannery (Site-II), fertilizer factory (Site-III) and cement factory (Site-IV) and collected on profile basis and distance from the source points. Total Cd contents of soils in different sites ranged from 0 to 2.48 mg kg -1 while the values for Pb varied from 7.14 to 54.31 mg kg -1 . Ammonium acetate and 0.1 N HCl extractable Cd in the surface soils were in the range between 0.01 and 0.62 mg kg -1 and between 0.03 and 1.66 mg kg -1 , respectively. Lead contents in surface soils extracted with 1N NH 4 OAc and 0.1N HCl varied from 0.18 to 2.72 mg kg -1 and 2.00 to 50.51 mg kg -1 respectively. A close relationship between the total amounts of Cd and Pb and their extractable amounts with 1N NH 4 OAc and 0.1N HCl was found. The concentrations of total and extractable Cd and Pb were inversely correlated with soil pH. Strong positive correlations were observed for Cd and Pb with CEC and organic matter contents of soil.