Appraisal of heavy metal contamination in sediments of the Shitalakhya River in Bangladesh using pollution indices, geo-spatial, and multivariate statistical analysis

Rapid urbanization and industrialization have aggravated heavy metal contamination in river sediments of the riverine ecosystem in developing countries like Bangladesh owing to their toxicity and persistence. Sediments are dynamic components and useful indicators to understand the level of contamination and their associated ecological risks in the aquatic environment. The study was conducted to investigate the heavy metal contamination in sediments for assessing the ecological risks of an urban river of Bangladesh using principal component analysis (PCA), Pearson's correlation matrix, geo-accumulation index (I-geo), contamination factor (CF), contamination degree (CD), pollution load index (PLI), enrichment factors (EF), and potential ecological risk factor (RI). The ranges of Zn, Cr, Cu, Pb, and Cd in sediments were 42.22-99.55, 11.12-57.83, 7.98-53.31, 6.76-22.41, and 0.38-0.87 mg/kg, respectively. In the present study, heavy metal concentration in sediments followed the descending order of Zn > Cr > Cu > Pb > Cd, while the concentrations of Cu, Cr, and Cd were higher and the concentrations of Pb and Zn were lower than the toxicity reference value (TRV). Geoaccumulation index (I-geo) demonstrated that most of the sediment samples were unpolluted to moderately polluted. The PLI ranged from 0.334 to 1.209 that stated that sediments were moderately polluted by studied metals. The multivariate statistical analysis revealed that heavy metal contamination was influenced by multiple pollution sources. The extent of heavy metal pollution in the Shitalakhya River implies that the condition is much frightening to both the aquatic biota and inhabitants in the vicinity of the river.