PCDD/Fs, non-ortho PCBs and Other Organochlorine Compounds in Eggs of Black-tailed Gull from Breeding Grounds, Nan-Do and Hong-Do, Korea

In a previous study, we concluded that the resident birds such as black-tailed gull (Larus crassirostris) in Nakdong River Estuary (NRE), Korea, were more contaminated by PCDD/Fs and PCBs than migratory gulls and snipes, which are periodical visitors in this estuary. The present study investigated on the contaminants in black-tailed gull from two major breeding grounds (NanDo and HongDo) in Korea. The objectives were to determine the levels of PCDD/Fs, non-ortho PCBs, total PCBs, DDTs, HCHs, chlordane compounds (CHLs) and HCB in eggs of black-tailed gull, and to assess the toxicological impact of PCDD/Fs and non-ortho PCBs on their eggs on the basis of TEQ. All target compounds were detected from all tested eggs from two breeding grounds. The main PCDD/F congeners detected in black-tailed gull and their eggs were 1, 2, 3, 7, 8-PeCDD, 2, 3, 4, 7, 8-PeCDF and 1, 2, 3, 6, 7, 8-HxCDD/F. These congeners also dominated in the same species from other NRE location studied earlier. Among organochlorines (OCs) analysed in this study, PCB concentrations was the highest, and PCB 126 (3, 3′, 4, 4′, 5-PeCB) was the most predominant of the non-ortho PCBs. It was found that the penta-chlorinated planar compounds such as 1, 2, 3, 7, 8-PeCDD, 2, 3, 4, 7, 8-PeCDF and 3, 3′, 4, 4′, 5-PeCB (PCB 126) gave remarkably higher contribution to bird-TEQWHO.1998, compared to the other PCDD/Fs and non-ortho PCBs. The majority of TEQ in all samples was contributed by non-ortho PCBs. PCB 126 was the most important contributor, accounting for 67-88% of TEQs.High levels of TEQs in some of eggs analysed in this study were in the range of LOAEL for adverse reproduction of wood duck. For some organochlorines, there are apparent geographical variations in pollution levels in eggs between both breeding sites.