Spatio-Temporal Variability and Pollution Assessment of Selected Metals in Freshwater Sediments, Pakistan

This study, describes the temporal and spatial variability of selected metals (Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sr, and Zn) and their origins in surface sediments collected from ten sites of Mangla Dam, Pakistan, during pre- and post-monsoon seasons. The metal contents were determined using atomic absorption spectrometry. Contamination factor (CF), pollution load index (PLI), enrichment factor (EF), and geoaccumulation index were calculated for the assessment of sediment pollution. Among the metals, Cd, Co, Pb, and Zn revealed higher CF values in the sediments from sites S7-S10 where the PLI also indicated heavy pollution. The EFs for Cd, Co, Ni, Pb, and Zn were >10, suggesting major anthropogenic contributions. In comparison with sediment quality guidelines, the measured concentrations of Cd, Ni, and Pb showed a probability of frequent adverse effects on sediment dwelling biota. Cluster analysis indicated that Cd, Co, Ni, Pb, and Zn were mostly contributed by human activities. The results of this study would drive urgent attention to develop preventive actions and remediation processes to stop the degradation to improve the quality of the reservoir.