Contamination and potential toxicity of heavy metals in sediment of the ocean disposal site

This study investigates the distribution, and accumulation of heavy metals in sediments of ocean disposal site. Sediment samples which collected from eleven locations in the ocean disposal site pre quarterly in 2009 were analyzed for metal content (e.g., Hg, Pb, Cd, Cr, Cu, Zn, Ni and Al), organic matter, and grain size. Base on the research results, the metal concentrations varied from 0.11 mg/kg for Cd to 198 mg/kg for Zn. All heavy metal concentrations excluding Hg and Ni of dumping area center in ocean disposal site is higher than other sites. Referring to enrichment factor (EF) assessment, both Cu and Cr in sediments of disposal area showed minor enrichment (EF <3) when comparing with the reference point which is located at outside of disposal site. Moreover, referring to sediment quality guidelines (SQGs), and mean ERM quotient (m-ERM-q), the dredged sediment disposal site is classified as “Medium — low contamination levels” where most samples (97%) have a medium — low (30%) probability of toxicity pollution.