Assessment of heavy metal contamination in surface sediments of the west Guangdong coastal region, China

Heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn), organic carbon and grain size of 237 surface sediment samples and one sediment core, taken from the west Guangdong coastal region in January 2008, were analyzed to evaluate the spatial distribution and pollution status. Results show that the ranges of the measured heavy metal concentrations in sediments are as follows: 8.33-39.49 mg/kg for As, 0.1-1.49 mg/kg for Cd, 33-108 mg/kg for Cr, 11.5-78.8 mg/kg for Cu, 0.04-0.26 mg/kg for Hg, 21-73 mg/kg for Pb, 56-248 mg/kg for Zn. The heavy metal enrichment is closely associated with Corg and grain size. Both the metal enrichment factor and geoaccumulation index indicate that there was no detected pollution on metals As, Cr, Cu, Pb in our study area and a slight to moderate contamination of Cd, Hg and Zn. However, As, Cr and Cu have showed a certain risk.