Sediment Characteristics and Heavy Metal Distribution in a Tropical Coastal Environment: Ecological and Human Health Risk Assessment

Heavy metal (HM) contamination in coastal sediments presents significant environmental and human health concerns This study provides a site-specific integrated assessment of physicochemical properties, sediment texture, HM concentrations (Cu, Zn, Mn, Fe, Pb, Cd), contamination status, ecological risks, and human health implications in surface sediments from Sugandha Beach, Cox’s Bazar. Pollution status was evaluated using enrichment factor, geo-accumulation index, contamination factor, and pollution load index, while ecological and human health risks were assessed using deterministic and Monte Carlo simulation approaches. The sediments were predominantly alkaline (pH 8.15–8.41) and sandy (88.69–93.72%), with low organic matter content. Elevated Pb concentrations were observed at all sites, with localized enrichment of Cu and Zn, whereas Cd remained below detection limits. Contamination indices indicated moderate pollution at S-5 to S-6 and S-12, primarily driven by Pb and Cu. Ecological risk ranged from low to moderate, with Pb as the major contributor. Health risk assessments indicated acceptable non-carcinogenic and carcinogenic risks, although children exhibited higher exposure sensitivity. Multivariate analyses revealed that HM distribution was associated with mixed anthropogenic and natural inputs. These findings provide baseline data for a highly dynamic sandy beach system and support targeted monitoring and management strategies for coastal environmental protection.