SEASONAL VARIATION AND ECOLOGICAL RISK ASSESSMENT OF HEAVY METAL CONTAMINATION IN SURFACE WATERS OF THE GANGES RIVER (NORTHWESTERN BANGLADESH)

The present work is evaluating the seasonal variation in metal pollution and the ecological risk indices of surface water of the Ganges River (Northwestern Bangladesh). Concentrations of Cr, Pb, Ni, Cd, As, Cu and Zn in surface water samples were determined by Flame Atomic Absorption Spectrophotometry. The level of heavy metals did not exceed the permissible limits of drinking water according to Department of Environment (DOE), Bangladesh and World Health Organization (WHO). Only Cr and Cd concentrations exceeded the permissible limits for aquatic life standards of the United States Environmental Protection Agency (USEPA) and Canadian Council of Ministers of the Environment (CCME). The heavy metal pollution index (HPI) showed that the seasonal contamination level followed the order: summer (136.13 (DoE),…