Trace metals and organochlorines in the bamboo shark Chiloscyllium plagiosum from the southern waters of Hong Kong, China Andrew S. Cornish a,b , W.C. Ng a , Valerie C.M. Ho a , H.L. Wong c , James C.W. Lam c , Paul K.S. Lam c , Kenneth M.Y. Leung a, ⁎ a The Swire Institute of Marine Science, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong, China b Present address: WWF Hong Kong, 1 Tramway Path, Central, Hong Kong, China c Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China Received 7 August 2006; received in revised form 6 January 2007; accepted 11 January 2007 Abstract The bamboo shark Chiloscyllium plagiosum is an abundant benthic species along the shallow continental shelf of Southeast Asia. It is commonly taken by fishermen in China, India, Taiwan and Thailand for human consumption. This study measured trace metal and organochlorine concentrations in C. plagiosum collected from the southern waters of Hong Kong, China. Metals (Ag, Cd, Cr, Cu, Mn, Ni, Pb and Zn) were measured in three different tissues: dorsal muscle, spleen and liver. Polychlorinated biphenyls (PCBs) and chlorinated pesticides in the dorsal muscle were identified and quantified using gas chromatography. Metal concentrations varied among the three different tissues, with liver having higher levels of Ag and Cd, and spleen possessing higher levels of Cu and Mn. Both Ni and Pb in all tissues were below the detection limit. Tissue concentrations of Cr, Cu, Mn and Zn generally decreased with increasing body weight whilst no significant concentration-size relationship was found for other metals. In muscle tissues, total PCBs ranged from 1.056–4.771 ng/g (wet wt.) with a median of 1.801 ng/g, while total DDTs ranged from 0.602–23.55 ng/g with a median of 1.109 ng/g, in which p,p′-DDE was the predominant metabolite. Levels of total hexachlorohexanes and cyclodienes were low. The pesticide p,p′-DDT was the only compound found to be positively correlated with body weight, indicating temporal bioaccumulation of this compound. Zn concentrations in the muscle of C. plagiosum were comparatively higher than recorded in other shark species, however, concentrations of other metals and organochlorines were relatively low. C. plagiosum feeds primarily on polychaetes, shrimps and small fishes, and thus is unlikely to contain levels of contaminants of human health concern. © 2007 Elsevier B.V. All rights reserved. Keywords: Seafood safety; Ecological risk; Marine pollution; Chiloscyllium plagiosum 1. Introduction Trace metals in coastal waters of many Southeast Asian countries pose a potential threat to marine ecosystems, and to coastal inhabitants who rely heavily on seafood as a source of protein (Phillips and Tanabe, Science of the Total Environment 376 (2007) 335 – 345 www.elsevier.com/locate/scitotenv ⁎ Corresponding author. Tel.: +852 2299 0607; fax: +852 2517 6082. E-mail address: kmyleung@hkucc.hku.hk (K.M.Y. Leung). 0048-9697/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2007.01.070