Assessment of heavy metal contamination in the surficial sediments from the lower Meghna River estuary, Noakhali coast, Bangladesh

Sediment samples were collected from ten selected sites of the lower Meghna River estuary, and six heavy metals were analyzed with Atomic Absorption Spectrophotometry (AAS) to assess the contamination level and the metals’ association with sediment grain size. The current results revealed that the mean concentrations of the studied metals were ranked in descending order of iron (Fe) (1.29 × 103 mg/kg) > zinc (Zn) (42.41 mg/kg) > lead (Pb) (12.48 mg/kg) > chromium (Cr) (10.59 mg/kg) > copper (Cu) (6.22 mg/kg) > cadmium (Cd) (0.28 mg/kg). The geo-accumulation, contamination, and pollution load indexes suggested that the lower Meghna river estuary was not contaminated by Fe, Zn, Pb, Cr, and Cu. The mean size of the sediment ranged from 28.92 to 126.2 μm, and the Pearson correlation coefficient showed a significant association between Fe and Pb (coefficient of determination, r2 = 0.836; p