Geographical distribution of polybrominated diphenyl ethers (PBDEs) and organochlorines in small cetaceans from Asian waters Natsuko Kajiwara a , Satoko Kamikawa a , Karri Ramu a , Daisuke Ueno a , Tadasu K. Yamada b , Annamalai Subramanian a , Paul K.S. Lam c , Thomas A. Jefferson d , Maricar Prudente e , Kyu-Hyuck Chung f , Shinsuke Tanabe a, * a Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan b National Science Museum, 3-23-1 Hyakunin-cho, Shinjuku-ku, Tokyo 169-0073, Japan c Center for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, HKSAR, China d Southwest Fisheries Science Center, NMFS, NOAA, 8604 La Jolla Shores Drive, La Jolla, CA 92037-1508, USA e Science Education Department, De La Salle University, 2401 Taft Avenue, 1004 Manila, Philippines f Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon, Kyonggi-do, 440-746, Republic of Korea Available online 24 January 2006 Abstract Polybrominated diphenyl ethers (PBDEs) are one of the flame retardants widely used in plastics, textiles, electronic appliances, and electrical household appliances. In this study, PBDEs and organochlorine compounds (OCs) were determined in the archived samples from the Environmental Specimen Bank for Global Monitoring (es-BANK) at Ehime University. The blubber of cetaceans found stranded along the coasts of Japan, Hong Kong, the Philippines and India during the period from 1990 to 2001 were employed for chem- ical analysis to understand the present status of contamination and the specific accumulation of PBDEs. PBDEs were detected in all the cetacean samples analyzed, and concentrations were one or two orders of magnitude lower than for PCBs and DDTs. Concentrations of PBDEs ranged from a low value of 6.0 ng/g lipid wt. in spinner dolphin (Stenella longirostris) from India to a high value of 6000 ng/g lipid wt. in Indo-Pacific humpback dolphin (Sousa chinensis) from Hong Kong. No difference in PBDE levels between coastal and off- shore species from Japan was observed, implying the existence of pollution sources in this region other than Japan. Highest concentra- tions of PBDEs were found in animals from Hong Kong, followed by Japan, and much lower levels from the Philippines and India, suggesting that developing nations may also have pollution sources of PBDEs. Geographical distribution of PBDEs in Asian waters was different from PCBs but similar to DDTs. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: PBDEs; POPs; Organochlorines; Cetacean; Asia-Pacific; Japan 1. Introduction Polybrominated diphenyl ethers (PBDEs), the popular flame retardants, are now a worldwide problem even in remote areas (Ikonomou et al., 2002a; Birnbaum and Staskal, 2004; Ueno et al., 2004). PBDEs are structurally similar to PCBs and DDT and, therefore, their chemical properties, persistence and distribution in the environment follow similar patterns. They have been found to bioaccu- mulate and there are concerns over the health effects in ani- mals from exposure to PBDEs. They also have potential endocrine disrupting properties (Hallgren et al., 2001; McDonald, 2004). Another social concern is that PBDEs have the potential to form polybrominated dioxins and fur- ans when burnt, and toxicity of the resultant compounds was estimated to be similar to chlorinated dioxins (Wata- nabe and Sakai, 2003). 0045-6535/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2005.12.013 * Corresponding author. Tel.:/fax: +81 89 927 8171. E-mail address: shinsuke@agr.ehime-u.ac.jp (S. Tanabe). www.elsevier.com/locate/chemosphere Chemosphere 64 (2006) 287–295