ORGANOHALOGEN COMPOUNDS Vol. 58 (2002) 117 POLYCHLORINATED NAFTALENES AND DLPCBs FOOD CHAIN ACCUMULATION OF POLYCHLORINATED NAPHTHALENES IN THE RAISIN RIVER, MICHIGAN, USA Nobuyasu Hanari 1 , Kurunthachalam Kannan 2 , Yuichi Horii 1 , Sachi Taniyasu 1 , Nobuyoshi Yamashita 1 , David J. Jude 3 , John P. Giesy 2 1 National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba, Japan 2 National Food Safety and Toxicology Center, Michigan State University, East Lansing, Michigan, USA 3 Center for Great Lakes and Aquatic Sciences, 501 East University, Ann Arbor, Michigan, USA Introduction Polychlorinated naphthalenes (PCNs) are widespread, persistent environmental pollutants. PCNs have been detected in air, water and biota samples collected from the remote oceans including the Arctic and the Antarctic oceans 1-3 . An earlier study has reported bioaccumulation of PCNs in a marine food web of the Baltic Sea 4,5 . Patterns of PCNs retained in biota vary widely. It has been suggested that PCNs tend to bioconcentrate and biomagnify in lower trophic level organisms including fish, while biomagnification is less (<1) in biota at the higher trophic level in the food chain such as predatory birds, marine mammals and fishes. While the earlier study has made been in the marine food web, in this study, aquatic organisms collected in the Raisin River, Michigan, were analyzed for PCN congeners to examine food chain accumulation. Food chain accumulation of PCNs was compared with those of polychlorinated biphenyls (PCBs). Material and Methods The food chain samples analyzed in this study include, smallmouth bass, largemouth bass, round goby, zebra mussel, amphipods, phytoplankton and benthic algae. Muscle tissues were analyzed for fishes and soft tissues were analyzed for zebra mussel. Samples were collected from the Raisin River in Michigan during Sep-Oct 1999. A few samples collected in Sep-Oct 1998 were also used. Tissues from several individuals were pooled to obtain representative samples. Chloronaphthalene (CN) and chlorobiphenyl (CB) congeners were analyzed following the method described elsewhere with some modifications 6 . PCB congeners were identified and quantified using a gas chromatograph (Perkin Elmer series 600) equipped with 63 Ni electron capture detector (GC-ECD). Identification and quantification of individual PCN congeners were accomplished with a Hewlett Packard 6890 series high resolution gas chromatograph (HRGC) coupled to a JEOL JMS-700D high resolution mass spectrometer (HRMS). The mass resolution of the spectrometer was greater than 10 -4 mass units. Separation of PCN congeners was achieved by DB-17. The column oven temperature was programmed from 70 (1 min) to 180 o C at a rate of 15 o C /min, and then to 270 o C at 2 o C /min with a final hold time of 10 min. CN and CB congeners were determined by selected ion monitoring (SIM) at the two most intensive ions of the molecular ion cluster. Results and Discussion Concentrations of total PCNs in biota from the Raisin River were 30 to 6000 times less than those of total PCB concentrations. Total PCN concentrations were the greatest in zebra mussel and round