Contamination and ecological risk assessment of heavy metals in water and sediment from hubs of fish resource river in a developing country

Abstract River water and sediment embody environmental characteristics that give valuable information about the eco-environment. Due to rapid unplanned urbanization and industrialization, the aquatic environment of any urban river can be seriously polluted by heavy metals. Four heavy metals (As, Cr, Cd, and Pb) were analyzed in surface sediments and water from the Kirtankhola River located in the coastal area of Bangladesh. The decreasing pattern of metals was observed as Cr > Pb > As > Cd in both water and sediment. The heavy metal ranges were 1.67–7.31, 12.64–45.69, 0.01–1.59, and 8.03–35.68 μg/L in the water and 2.09–6.89, 14.76–47.08, 0.01–1.77 and 6.37–41.43 mg/kg in sediments for As, Cr, Cd, and Pb. The number of metals tested in water samples surpassed the acceptable limits of drinking water quality, indicating that water from this river is not safe for drinking and cooking and could pose a risk to the riverine ecosystem. The pollution load index (PLI) values were close to one, indicating that the sediment of the study river was low contamination. Contamination factor (CF) has reported that As, Cd, and Pb have been moderate to extremely polluted by sediment samples and metals level implied that the condition is much alarming and probably severely affecting the aquatic ecology of this riverine ecosystem.