title: An assessment of the risks associated with polychlorinated biphenyls found in the stomach contents of stranded Indo-Pacific Humpback Dolphins (Sousa chinensis) and Finless Porpoises (Neophocaena phocaenoides) from Hong Kong waters.
abstract: The risks to Indo-Pacific Humpback Dolphins and Finless Porpoises associated with polychlorinated biphenyls (PCBs) were assessed. Stomach contents from twelve stranded Humpback Dolphins and sixteen stranded Finless Porpoises were collected. Concentrations of total and isomer-specific PCBs in the stomach contents were determined using dual-column gas chromatography equipped with electron capture detectors (GC-ECD). Risks due to the PCBs were assessed in three scenarios, based on total PCBs (summation of 41 PCB congeners), total toxicity equivalency (TEQs) and PCB 118, using the toxicity reference values (TRVs) as the threshold effects benchmarks. The calculated risk quotients (RQs) showed that risks due to PCBs were generally low or negligible. Specifically, RQs from total TEQs and total PCBs for Finless Porpoises are below one, suggesting that PCBs should be a low risk for the Finless Porpoise in Hong Kong waters. However, the Humpback Dolphin has RQs larger than 1 for total TEQs and total PCBs when the 95th percentile data were used in the evaluation. This indicates that further investigation may be needed to examine more closely the potential impact of toxic contaminants in the habitat of the Humpback Dolphin.
authors.affiliation: Department of Biology and Chemistry, Centre for Coastal Pollution and Conservation, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
authors.forename: Craig L H
authors.initials: CL
authors.lastname: Hung
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: James C W
authors.initials: JC
authors.lastname: Lam
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Jefferson
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Hung
authors.forename: Leo W Y
authors.initials: LW
authors.lastname: Yeung
authors.forename: Michael H W
authors.initials: MH
authors.lastname: Lam
authors.forename: Desmond K
authors.initials: DK
authors.lastname: O'Toole
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Lam
mesh_terms: D000818:Animals; D004289:Dolphins; D005766:Gastrointestinal Contents / Q000737:chemistry*; D006723:Hong Kong; D010140:Pacific Ocean; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000633:toxicity; D019576:Porpoises; D012016:Reference Values; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls