Bioaccumulation and biotransformation of pyrene and 1-hydroxypyrene by the marine whelk buccinum undatum

The fates of a phenolic contaminant and its hydrocarbon precursor have rarely been compared, especially in an invertebrate species. Two groups of Buccinum undatum were exposed to equimolar amounts of pyrene and 1-hydroxypyrene over 15 d through their diets. Tissue extracts from the muscle and visceral mass were analyzed by liquid chromatography with fluorescence and mass spectrometry detection. Nine biotransformation products were detected in animals from both exposures. These included 1-hydroxypyrene, pyrene-1-sulfate, pyrene-1-glucuronide, pyrene glucose sulfate, two isomers each of pyrenediol sulfate and pyrenediol disulfate, and one isomer of pyrenediol glucuronide sulfate. These compounds represent a more complex metabolic pathway for pyrene than is typically reported. Diconjugated metabolites were as important in animals exposed to pyrene as in those exposed to 1-hydroxypyrene. Biotransformation products represented >90% of the material detected in the animals and highlight the importance of analyzing metabolites when assessing exposure. A mean of only 2 to 3%of the body burden was present in muscle compared with the visceral mass of both groups. The analytical methods were sufficiently sensitive to detect biotransformation products both in laboratory control whelks and in those sampled offshore. The tissue distribution of [ ¹⁴C]pyrene was also studied by autoradiography. Radioactivity was present primarily in the digestive and excretory system of the whelks and not in the gonads or muscle tissue.