title: Ecotoxicological assessment of persistent organic and heavy metal contamination in Hong Kong coastal sediment.
abstract: The aim of the present project is to determine the feasibility of measuring hepatic cytochrome P4501A1 (CYP1A1) and metallothionein (MT) mRNA in fish as an integrative measurement of persistent organic pollutants (POPs) and heavy metal contamination in sediment arising in Hong Kong. Sediment samples were collected from different sites, including Victoria Harbour (VS6), Yim Tin Tsai (YTT) at Tolo Harbour, Mai Po marshes (MPM) at Deep Bay, and Southern Waters (SS6) of coastal waters. The samples were analyzed for total and extractable concentrations of Cd, Cu, Ni, Zn, and Pb, as well as PCBs and PAHs. In addition, biomarker responses were studied in tilapia exposed experimentally to coastal sediment for 7 days. Using RT-PCR technique, hepatic CYP1A1 and MT mRNA were measured. Three control groups were used, including one negative control group maintained in sea water only; the second and third positive control groups were in sea water but were intraperitoneally injected with either beta-naphthoflavone (40 microg/g body weight) or cadmium chloride (10 microg/g body weight), respectively. The chemical data showed that VS6, YTT, and MPM were classified as Class C sediment according to the sediment quality criteria defined by the Hong Kong Environmental Protection Department, indicating the sites were heavily polluted. The exposure of tilapia to the sediment induced hepatic CYP1A1 (VS6 > YTT > MPM > SS6) and MT (VS6 > MPM > YTT > SS6) levels. The induction patterns were comparable to the levels of POPs and metal contamination in the sediment, indicating that the biomarker responses could be used to differentiate low to high levels of contamination among sediment.
authors.affiliation: Department of Biology and Institute for Natural Resources and Waste Management, Hong Kong Baptist University, Kowloon Tong.
authors.forename: C K
authors.initials: CK
authors.lastname: Wong
authors.forename: H Y
authors.initials: HY
authors.lastname: Yeung
authors.forename: R Y
authors.initials: RY
authors.lastname: Cheung
authors.forename: K K
authors.initials: KK
authors.lastname: Yung
authors.forename: M H
authors.initials: MH
authors.lastname: Wong
mesh_terms: D000818:Animals; D019256:Cadmium Chloride / Q000633:toxicity; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D005069:Evaluation Studies as Topic; D019015:Geologic Sediments / Q000737:chemistry*; D006723:Hong Kong; D008099:Liver / Q000201:enzymology; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D019216:Metals, Heavy / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017210:Tilapia / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis*; D019324:beta-Naphthoflavone / Q000633:toxicity
chemical_list: D017931:DNA Primers; D019216:Metals, Heavy; D011084:Polycyclic Aromatic Hydrocarbons; D012333:RNA, Messenger; D014874:Water Pollutants, Chemical; D019324:beta-Naphthoflavone; D004247:DNA; D008668:Metallothionein; D011078:Polychlorinated Biphenyls; D019363:Cytochrome P-450 CYP1A1; D019256:Cadmium Chloride