Alkylated phenanthrene distributions in black rockfish (Sebastes schlegelii) and biotransformation into hydroxylated metabolites after intragastric administration

Highlights: • Methylated phenanthrenes were detected in blood and liver but not in bile. • Parent methylated phenanthrene concentrations decreased by >98% 8 d after exposure. • Hydroxylated metabolites were found in bile but not in blood and liver. • Metabolite concentrations in bile remained constant for >8 d after exposure. Marine organisms such as fish are at risk of exposure to petrogenic polycyclic aromatic hydrocarbons (PAHs) released in oil spills. PAH toxicities are affected by the rates of PAH biotransformation and elimination in fish tissues, but little information on these rates is available. In this study, the biotransformation and tissue distribution of methylated phenanthrenes—typical petrogenic PAHs found after oil spills—in black rockfish (Sebastes schlegelii) were investigated. Two groups of fish were used. Each fish in one group was given a single intragastric dose of 3-methylphenanthrene, and each fish in the other group was given a single intragastric dose of 3,6-dimethylphenanthrene. The fish were allowed to recover in purified sea water for 196 h. Methylated phenanthrenes were detected in only blood and liver for 24 h after dosing, but the concentrations decreased over time and > 98% had been eliminated by the end of the study. Four mono-hydroxylated metabolites of 3,6-dimethylphenanthrene and six mono-hydroxylated metabolites of 3-methylphenanthrene were tentatively identified for the first time from tandem mass spectrometry analyses of fish bile. The concentrations of these metabolites in bile remained constant for 192 h, suggesting that the metabolites could be used as biomarkers of rockfish exposure to petrogenic PAHs.