Risk Assessment of Heavy Metals in Sediments from Xiangshan Harbor, Sanmen Bay and Hangzhou Bay

• • Mean Cu and Cr concentrations in Xiangshan Harbor sediments exceeded the Class I marine sediment quality standard (GB 18668-2002) by 1.03× and 1.1×, respectively, indicating localized contamination that may threaten benthic organisms and necessitate targeted remediation. • • In Sanmen Bay, mean Cr exceeded the standard by 1.1×, while Cu did not; this differential accumulation suggests distinct sources and requires source-specific management strategies. • • Coefficients of variation for five heavy metals in Hangzhou Bay exceeded 30%, signifying strong anthropogenic influence; spatial analysis traced contamination to a chemical industrial park, with concentrations decreasing westward, directly implicating industrial discharge as the primary driver. • • The potential ecological risk indices (RI) for Xiangshan Harbor, Sanmen Bay, and Hangzhou Bay were 38.5, 36.7, and 31.1, respectively, all below the low-risk threshold (RI < 150), confirming overall low ecological risk but warranting continued monitoring due to localized hotspots.