Environmental impact of heavy metal contamination in coastal sediments and saltmarshes of Palk Bay and Gulf of Mannar, Southeast India

This current study investigates the bioaccumulation of heavy metals in salt marsh plants from Palk Bay and the Gulf of Mannar, Southeast India, emphasizing seasonal variations (Monsoon and Summer) in metal uptake. Eleven plant species, including A. halimus, S. littoreus, and S. maritima, were analysed across two seasons for cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) concentrations in plant tissues and sediments. Results indicate higher metal accumulation during monsoon, with substantial uptake of Cu, Zn, and Cr by A. halimus and S. littoreus. Igeo standards for sediments suggests negligible Cd contamination, low Cr and Cu contamination, and moderate Zn contamination during summer. The investigation concluded that the heavy metal contamination in sediments was noted as, Cd > Pb > Cr > Cu > Zn for monsoon; Cr > Cu > Zn > Pb > Cd for summer seasons. The Contamination Degree (CD) and Potential Ecological Risk (PER) indices identified stations S5, S8, and S9 as areas of concern, especially in summer. This study highlights salt marsh plants as effective bioindicators of heavy metal pollution in coastal ecosystems.