Heavy metal contamination in surface water and sediment of the Meghna River, Bangladesh

Globally alarming ten heavy metal (Zn, Al, Cd, Pb, Cu, Ni, Fe, Mn, Cr, Co) concentrations were estimated in surface water and sediment of the Meghna River in Bangladesh from September 2015 to March 2016. Heavy metals were analyzed by Atomic Absorption Spectrophotometer (AAS). Results indicated that, all the metals in water were found below the safe limit of drinking water standard of WHO (1993) and EU (1998) with the exclusion of Fe, Ni and Al. In sediment, all the trace metals were recorded below the limit compared to other scientific results. For three seasons at two sampling points no significant difference in heavy metals was founded at the significance level (p > 0.05). Multivariate statistical analyses such as principal component analysis and correlation matrix disclosed prevalent anthropogenic interferences of Zn, Al, Cd, Pb, Cu, Ni, Fe, Mn, Cr, Co in water and sediment. The very strong positive correlation was recorded between Fe vs Al (0.992), Mn v's Cu (0.948), Fe vs Mn (0.939), Zn vs Al (0.929), Fe vs Zn (0.920) in water. In sediment, very strong linear relationships were found in Cd vs Zn (0.999), Cd vs Cu (0.998), Zn vs Cu (0.996), Cd vs Ni (0.995), Ni vs Cu (0.994), Ni vs Zn (0.993) etc. at the 0.05 significance level which direct their common origin exclusively from industrial effluents, municipal wastes and agricultural inputs. Necessary steps should be taken to protect this River from pollution and also to reduce the environmental risk.