Trace element concentration in surface sediments of Palk Strait, southeast coast of Tamil Nadu, India

• The metal accumulation was investigated in the coral and mangrove ecosystem.
• The elemental accumulation was chiefly controlled by CaCO3 content and riverine input.
• The marine sediments are chiefly enriched by Ni, Mn, Cu, Pb, Cd, Cr, followed by Zn.
• Pollution Load Index (PLI) values reveal that all the samples are falling under moderately to unpolluted category.

The present work was carried to decipher the trace element accumulation in surface sediments of Palk Strait, southeast coast of Tamil Nadu, India. The elemental concentration and correlation results suggest that fine fractions with CaCO3 content followed by organic matter (OM) of the surface sediments control the trace element accumulation in the study area. In addition, Fe and Mn concentration is chiefly contributed from riverine process and controlled by the mangrove ecosystem. The other elements are derived into marine environment through confluence of untreated industrial pollutants into the river system. The EF result shows that the studied marine sediments are enriched by Ni, Mn, Cu, Pb, Cd, Cr, followed by Zn. The order of the pollution intensity with respect to geo-accumulation index suggests the following ascending order: Ni > Mn > Fe > Cu > Pb > Cd > Cr > Zn. Pollution Load Index (PLI) values reveal that all the samples are falling under moderately to unpolluted category.