| Abstract Submission No. | ABS-3.1-0056 |
| Title of Abstract | Seasonal and spatial variations in geochemical fractionation of heavy metals (Ni, Cr, Pb, & Cu) in Coastal sediments of the central and south-west coast of India |
| Authors | Krushna Vudamala*, Khulood Thahani, Sarang S. Deep, PrajinPrakash, Karnan Chinnadurai, Kanakam Anil |
| Organisation | CSIR-National Institute of Oceanography |
| Address | Dona paula North Goa, Goa, India Pincode: 403004 E-mail: krushna.nio@csir.res.in |
| Country | India |
| Presentation | Oral |
| Abstract | Heavy metals in coastal sediments pose significant ecological risks due to their persistence and potential bioavailability. This study investigates the seasonal and spatial variations in the distribution and geochemical fractionation of nickel (Ni), chromium (Cr), lead (Pb), and copper (Cu) in sediments from off the coast of Kochi and off the coast of Goa, along the central and southwest coasts of India. Sampling was conducted during the post-southwest monsoon (September 2022), northeast monsoon (December 2022), and spring inter-monsoon (March 2023) seasons. Physicochemical parameters (TC, TIC, TN, pH, salinity, and temperature) and sediment texture (sand, silt, and clay) were evaluated to understand their role in metal enrichment. Sequential extraction followed by ICPMS analysis (recoveries: Ni 105%, Cu 105%, Pb 104%, Cr 97.4%) showed that Ni, Cu, and Cr were predominantly associated with organic matter, whereas Pb was mainly confined to the residual fraction. Seasonal differences were more pronounced in Goa, particularly post¿southwest monsoon, where metals followed the order (Fraction: Fr) Fr4 > Fr3 > Fr2 > Fr1. Total concentrations at several sites approached or exceeded the Effect Range Median (ERM) values. Correlation analysis revealed strong associations between metals, organic matter, and nitrogen under aerobic conditions. While Ni, Cu, and Pb showed affinity for finer silt and clay fractions, Cr was preferentially linked to sand. These findings highlight the influence of organic matter and sediment texture on metal binding and underscore the need for continuous monitoring to assess long-term impacts. |
| Keywords | Heavy metals; Fractionation; Seasonal variability; Coastal sediments; Central west; and coast of India |