Geographical distribution and accumulation features of organochlorine residues in bivalves from coastal areas of South Korea.

As a part of Mussel Watch Program in Korea, the contamination levels and accumulation features of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed for 82 bivalve samples collected from 66 sites along the entire coast of Korea. The dry weight based sigmaPCBs and sigmaOCPs ranged from 4.4 ng g(-1) to 422.0 ng g(-1) (geometric mean = 36.9 ng g(-1)) and from 9.95 ng g(-1) to 131.37 (34.88) ng g(-1), respectively. PCB was predominant in Korean coast, followed by DDTs, HCHs, and Chlordanes. From the observed log normal distribution of PCB and each OCP, low- and high-levels were defined as geometric mean +/- 1 S.D., respectively. The levels at the sites near urban and/or industrial areas often exceeded the high-levels and the spatial distributions of sigmaDDTs and sigmaCHLs were correlated with that of sigmaPCBs, indicating terrestrial input pathways. Even distribution of sigmaHCHs suggested a possibility of atmospheric input pathway of HCHs. The observed isomer ratios of DDTs, HCHs, and CHLs indicated that aging has occurred.