Metal Distribution in Shallow Core Sediments of Mullipallam Creek, South East Coast of India

Over the past decades coastal wetland environment have more sediment contamination both nature and anthropogenic. Also sediment can absorb persistent and toxic chemicals to levels many times higher than water column. In order to we evaluated the metal distribution in two shallow core sediments of Mullipallam creek from south east coast of India by analyzing the concentrations of both major and trace elements (Ca, K, Cu, Pb, Zn, Mn, Zr, Sr and Ti). The sediments comprise of dominant mud (>90%) and the concentration of CaCO3 is low in upper half of the cores compared to the lower parts. Multivariate statistical analysis indicates significant correlation between sulfur and Fe indicating co-precipitation of both as Fe-sulfide or adsorption of Fe onto the finer sediments (clay minerals) in an anoxic environment of deposition. Correlation between sand and organic carbon (r=0.52, Core 2) indicates that it is either due to coarse vegetal organic debris or induced adsorption of organic matter on to the mineral grain surface. Similarly the association of CaCO3 and Mn (r=0.59, 0.42) indicates calcium carbonate precipitated as Mn carbonate in the sediment. Also the fine grained fraction facilitates the uptake of metals like Fe, Mn, Zn and Ti and coarse grain facilitates Ca, K, Sr and Zr in core sediments. Further quality of the sediments were evaluated based on the Enrichment factor (EF), Geo accumulation Index (Igeo) and Pollution load index (PLI). The result reveals that creek sediments show moderate level of pollution with respect to the Enrichment Factors of Pb, Zr ad Sr. Similarly, the Contamination Factor indicates moderate level contamination with respect to Pb and Zr. The dominant Pb in the sediments could be sourced from coal burning power generation plants and other minor industrial activities in the region close to wetland and from open coastal water. Keywords: Metal, contamination, coastal wetland, Mullipallam