SPATIAL AND TEMPORAL DISTRIBUTION OF HEAVY METALS IN THE BURIGANGA RIVER

This article represents the spatial distributions of heavy metals in water at sixteen different sites spread over the whole stretch of the Buriganga River (27km). The concentrations of seven metals, Cr, Cd, Pb, Ni, Fe, Zn, and Cu, were analyzed using an Atomic Absorption Spectrophotometer (Thermo-Scientific, 3000 series) in the RRI laboratory. The concentrations were compared with several standard guidelines provided by organizations like WHO, DoE, FAO, and CCME. The visualization of the spatial pattern of individual metal throughout the Buriganga was primed using ArcGIS 10.3 software. The result showed that these heavy metals severely polluted the surface water of the whole stretch of the Buriganga in the dry season except Cu and Zn. The statistical analysis showed a wide variation of concentrations among Cr, Cd, Pb, Ni, Fe, Zn, and Cu but slightly differed among the locations. Anthropogenic activities are mainly responsible for elevated levels of the measured metals in river water. A lower heavy metal concentration was found in the post-rainy season compared to the dry season. Even though the concentration has decreased post rainy season, some severe toxic heavy metals like Cr and Cd concentrations are far above the safe recommended values