ACCUMULATION AND METABOLISM OF CARBON-14 LABELED BENZENE, NAPHTHALENE, AND ANTHRACENE BY YOUNG COHO SALMON (ONCORHYNCHUSKISUTCH) WILLIAM T. ROUBAL,TRACYK. COLLIER and DONALD C. MALrNS Northwest and Alaska Fisheries Center National Marine Fisheries Service National Oceanic and Atmospheric Administration 2725 Montlake Boulevard East Seattle. Washington 98112 Carbon-14 labeled benzene, naphthalene, and anthracene were administered to young coho salmon (Oncorhynchus kisutch) in the food and by intraperitoneal injection. Regardless of the mode of application the accumulated carbon-14 (% administered dose) in key organs (e.g., liver and brain) increased in the order anthracene > naphthalene > benzene over vari- ous time periods. The metabolic fate of the hydrocarbons after intraperitoneal injection was studied. It was shown that the highest percentages of metabolites occurred in the gall bladder; however, significant amounts were also found in the liver, brain, flesh, and "carcass." Solvent partition and thin-layer chromatographic techniques were developed to determine the structure of individual metabolites. In brain, liver, and gall bladder, l-naphthol and 1-naphthyl glucuronic acid were major products of naphthalene metabolism; however, glycoside/sulfate fractions and mercapturic acid were indicated. The heart and flesh were rich in l-naphthol and the former organ contained significant amounts of 1,2-dihydro-l,2- dihydroxynaphthalene. The findings indicated that the aromatic hydrocarbons in key organs increased in relation to the number of benzenoid rings. Further, it appears that aromatic metabolites are broadly distributed throughout fish exposed to polynuclear aromatic hyd- rocarbons. It is well known that hydrocarbons induce physiological and biochemical changes in aquatic organisms (Struhsaker et al. 1974, Anderson et al. 1974, Heitz et al. 1974, Dun- ning and Major 1974, Jacobson and Boylan 1973, Brocksen and Bailey 1973, Roubal and Collier 1975); however, only a few studies present detailed information on the metabolic fate of ingested petroleum hydrocarbons (Malins 1977a and 1977b, Varanasi and Malins 1977). Lee et al. (1972b) studied the uptake and discharge of hydrocarbons by mudsucker, sculpin, and sanddab. Also, Lee et al. (1972a) studied the uptake of 14C-heptadecane and 14C-naphthalene in the mussel, Mytilus edulis. Moreover, Comer et al. (1973) investigated the uptake and metabolism of naphthalene by the spider crab, Maia squinado. Recently, Lee (1975) provided data on the metabolic fate of petroleum hydrocarbons in marine zooplankton. Archives of Environmental Contamination and Toxicology Vol. 5. 513-529 (1977) 9 1977 by Springer-VerlagNew YorkInc.