Temporal variation and biomagnification of organohalogen compounds in finless porpoises (Neophocaena phocaenoides) from the South China Sea Karri Ramu a , Natsuko Kajiwara a , Paul K.S. Lam b , Thomas A. Jefferson c , Kaiya Zhou d , Shinsuke Tanabe a, * a Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime Prefecture 790-8577, Japan b Department of Biology and Chemistry, Center for Coastal Pollution and Conservation, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China c Southwest Fisheries Science Center, NOAA, Fisheries, 8604 La Jolla Shores Drive, La Jolla, CA 92037, USA d Jiangsu Key Laboratory for Bioresource Technology, College of Life Sciences, Nanjing Normal University, Nanjing 210097, P.R. China Received 21 September 2005; received in revised form 16 January 2006; accepted 17 January 2006 Levels and temporal variations of organohalogen contaminants in the South China Sea. Abstract Polybrominated diphenyl ethers (PBDEs) and organochlorine compounds (OCs) were determined in the blubber of male finless porpoises (Neophocaena phocaenoides) collected in 1990 and 2000/01 from the South China Sea. Among the organohalogen compounds analyzed, DDTs and PCBs were the predominant contaminants in the porpoises, ranging from 26,000 to 260,000 and 1400 to 28,000 ng/g lipid wt., respectively. PBDEs ranged from a minimum of 84 ng/g lipid wt., in 1990 to a maximum of 980 ng/g lipid wt., in 2001, showing a significant increase during the time period investigated. Congener profiles in finless porpoises did not shift to higher BDE congeners during these years, implying a continuous discharge of lower BDE commercial mixtures, such as PentaBDE. For OCs, HCHs concentrations decreased significantly, while others did not exhibit any significant temporal variation. Biomagnification factors (BMFs) were found to be highest for CHLs and lowest for HCB. PBDEs and PCBs had comparable BMFs, indicating a similar potential for biomagnification through the food web. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: South China Sea; Finless porpoise; Organochlorines; Polybrominated diphenyl ethers; Temporal variation 1. Introduction Polybrominated diphenyl ethers (PBDEs) are man-made chemicals used as flame retardants in a variety of consumer products such as electronic equipment, building materials, automobiles and textiles (Haglund et al., 1997). High binding affinity to particles, and their lipophilic nature made PBDEs ubiquitous environmental contaminants in both aquatic and terrestrial environments (de Wit, 2002). Concerns have been mounting over the increasing concentrations of PBDEs in aquatic biota, because of the evidence that they may exert toxic effects similar to those of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins and furans (Darnerud et al., 2001). Although levels of organochlorine compounds (OCs) in various environmental matrices show declining trends due to the ban on their use and production, several temporal trend studies indicate the continuous increase of PBDE levels in the North American environment (Norstrom et al., 2002), Cana- dian Arctic (Ikonomou et al., 2002), Japan (Akutsu et al., 2003; Choi et al., 2003) and Sweden (Nore ´n and Meironyte ´, 2000). These studies indicate that PBDE concentrations in the environment increased substantially since the large scale PBDE production began in the early 1970s. * Corresponding author. Tel./fax: þ81 89 927 8171. E-mail address: shinsuke@agr.ehime-u.ac.jp (S. Tanabe). 0269-7491/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2006.01.027 Environmental Pollution 144 (2006) 516e523 www.elsevier.com/locate/envpol