Trace metals in water, sediment and fishes of the Ganges-Brahmaputra-Meghna Delta, Bangladesh: A Review

Author: Md. Kawser Ahmed, Seema Rani, Makidul Islam Khan, Pierre Failler, Md. Monirul Islam, Gordon Watson
DOI: doi.org/10.70279/bmj-v5-i2-1024
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The Ganges-Brahmaputra-Meghna (GBM) Delta, a transboundary delta, is the world’s largest delta which is believed to be contaminated with many pollutants including heavy metals. This study systematically reviewed heavy metal pollution in water, sediments and fish in different rivers of the GBM Delta, Bangladesh. This study evaluated total 12 heavy metals (Cr, Cd, Hg, As, Zn, Cu, Fe, Co, Pb, Ni, Mn and Ba) which are mostly reported in different rivers of the GBM Delta. Most of the heavy metals’ mean concentration in water, sediments and fish exceeded the maximum permissible limits (MPLs) in the Buriganga, Bangshi, Dhaleshawri, Karnaphuli and Korotoa rivers because of direct or indirect discharge of significant levels of untreated industrial effluents, municipal sewage, domestic wastes and agricultural runoffs. However, the level of heavy metal contamination in water and sediments of the upper Ganges were below the MPLs. This might be caused by the effects of higher water flow in the river. The concentration of heavy metals in sediments and fish were reported much higher than waters as metals tend to deposit to the bottom of the water column and also accumulate in the fishes’ tissues. We conclude that a few of the rivers of GBM delta are highly contaminated by heavy metals and there is potential risk concern for ecosystem and public health. This study recommends effective waste management strategies to control heavy metals pollution in different rivers of the GBM Delta in future.