Assessment of sediment contamination by persistent organic pollutants in Gyeonggi Bay, Korea

Persistent organic pollutants were determined in 33 surface sediments from Gyeonggi Bay, Korea. The concentrations (ng/g dry weight-range, mean in brackets) of PCBs, DDTs and HCHs in sediments were 0.16–41.9 (2.22), 0.03–5.17 (0.67) and 0.03–0.88 (0.29), respectively. Sum of 24 PAHs ranged from 6.37 to 648 ng/g (111 ng/g). Tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) were detected in 10, 3 and 31 out of 33 stations surveyed. TBT, DBT, and MBT were in the range of non detectable (n.d.)-122 ng Sn/g, n.d.-84 ng Sn/g, and n.d.-41 ng Sn/g respectively. t-octylphenol, nonylphenol and bisphenol-A were in range of 0.1–15.4 ng/g, 3–1070 ng/g and 0.2–15.9 ng/g, respectively. These levels are lower than in other Korean bays. Station K8, located close to a wastewater reservoir showed the highest concentration. Molecular tracers such as nonylphenol, t-octylphenol, bisphenol-A, indicated that PCBs and PAHs entered the bay through sewage discharge, while butyltins, DDTs and HCHs entered either through atmospheric depositions or from shipping activities. According to international sediment quality guidelines, the noted concentrations may not impact benthic life.