Assessing metal contamination in recent creek sediments using fractionation technique along Mumbai coast, India

Abstract

Three sediment cores from a creek environment in Mumbai, extending from the head to the creek mouth, were studied with respect to elements (Fe, Mn, Cu, Pb, Co, Zn and Cr) along with organic matter (total organic carbon, total phosphorus, total nitrogen) and sediment components (sand, silt, clay). A sequential extraction procedure was also applied to understand the partitioning of trace metals among the different fractions of the sediment. Together with this data, pollution indices were also computed and comparison with numerical sediment quality guidelines carried out. Correlation analysis among the different variables displayed weaker relations of metals with the sediment components, while organic matter and Fe-Mn oxyhydroxides were found to act as important substrates for metal sequestration in the creek region. The fractionation results reveal almost all the elements were associated with the residual fraction, while Mn was high in the bioavailable fraction.