Concentration and Ecological Risk of Heavy Metals in River Sediments of a Developing Country: A Meta-Analysis

Heavy metals (HMs) contamination in sediment presents a straightforward issue, particularly noticeable in developing nations. Addressing this problem requires an extensive inquiry into the present situation and potential remedies to keep safe environment. This document compiles statistical procedures concerning various heavy metals such as chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd), lead (Pb), and arsenic (As) that are available in sediments from Bangladesh spanning the years from 1998 to 2021. The average levels of Ni, Cu, Cd, Pb, and As in sediments of the available data exceeded the corresponding background values, upper continental crust values, and toxicity reference values, indicating severe contamination of sediment by heavy metals. Metal concentrations (Cr, Ni, Cu, and As) generally remained lower than the average shale values, except for Cd and Pb. By utilizing the Pearson correlation coefficient (CCA) and principal component analysis (PCA), it was evidenced that human activities, apart from natural ecological factors, stand as the primary sources of heavy metal pollution in sediment from Bangladeshi waterways. Cd emerged as the key contributor to heightened contamination levels in riverine sediments, as indicated by pollution indices, signifying an ecological hazard. Overall, the data underscored the significant ecological risk posed by the considered hazardous metals. To mitigate sediment heavy metal levels, strategies such as reducing heavy metal discharges at their origins and implementing phytoremediation techniques in sediment, along with improving effluent treatment facilities, could aid in alleviating the issue.