Integrative assessment of sediment contamination by toxic substances in Ulsan Bay

Abstract

In order to assess the contamination status and identify the priority substances in Ulasn bay, an intensive sediment sampling was conducted and thirty two contaminants were analyzed. The sediment quality index (SQI) was derived based onthe contaminant data by comparing with sediment quality guidelines (SQGs) established in Korea, Canada, and Autstraila/Newzealand (ANZECC). Toxic contaminants were found to be widely distributed across the coast. Among the target compounds,butyltins showed the highest concentration, followed by PAHs, nonylphenols, PCBs, DDTs, HCHs and CHLs. Heavy metals were also abundantly detected with the highest concentration of Zn followed by Cu > Pb > Cr > Ni > As > Cd > Hg. Compared toorganic contaminants, most heavy metals, except for Cu and Hg, were homogeneously distributed along the coast in a good relationship with total organic carbon of sediment particles. The sites located near industrial and large shipyard area showed relatively higher concentrations than those of other sites. In general, the concentrations of organic compounds and metals were highest at inner coastal stations with a tendency of declining from inside to outside, indicating a great loading of pollutants from inland activities. The high exeedance for low-SQGs and high-SQGs was found for TBT, Zn, Cu, As, Hg and Pb. The SQI scores calculated from low-SQGs and high-SQGs were in the range of 25 - 100 and 71 - 100, resphe contaminant data by comparing with sediment quality guidelines (SQGs) established in Korea, Canada, and Autstraila/Newzealand (ANZECC). Toxic contaminants were found to be widely distributed across the coast. Among the target compounds,butyltins showed the highest concentration, followed by PAHs, nonylphenols, PCBs, DDTs, HCHs and CHLs. Heavy metals were also abundantly detected with the highest concentration of Zn followed by Cu > Pb > Cr > Ni > As > Cd > Hg. Compared toorganic contaminants, most heavy metals, except for Cu and Hg, were homogeneously distributed along the coast in a good relationship with total organic carbon of sediment particles. The sites located near industrial and large shipyard area showed relatively higher concentrations than those of other sites. In general, the concentrations of organic compounds and metals were highest at inner coastal stations with a tendency of declining from inside to outside, indicating a great loading of pollutants from inland activities. The high exeedance for low-SQGs and high-SQGs was found for TBT, Zn, Cu, As, Hg and Pb. The SQI scores calculated from low-SQGs and high-SQGs were in the range of 25 - 100 and 71 - 100, resp