ELIMINATION OF SEDIMENT-ASSOCIATED BENZO[A]PYRENE AND ITS METABOLITESBY POLYCHAETE WORMS EXPOSED TO 3-METHYLCHOLANTHRENE

Polychaete worms can be important vectors for the accumulation and tra nsfer of sediment-associated organic contaminants, including polycycli c aromatic hydrocarbons (PAHs). Differences between species in ability to metabolize and eliminate organic compounds may contribute to diffe rences in steady state body burdens of parent compound and metabolites . In this study, three species of polychaete worms, Leitoscoloplos fra gilis, Marenzellaria viridis, and Nereis diversicolor, were exposed to trace quantities of the radiolabelled PAH, benzo[a]pyrene (BaP) in se diment, with or without 3-methylcholanthrene (3MC), a compound known t o induce metabolism of PAHs in other species. After exposure, worms we re transferred to clean sediment and the rate of elimination of parent compound and disposition of metabolites was followed for up to 17 day s. Elimination of parent compound was slowest in L. fragilis (half-lif e = 10.3 d), the species with the most limited ability to metabolize B aP. Elimination of parent BaP was more rapid in M. viridis (half-life = 5.1 d) and N. diversicolor (3.7 d), species which metabolize BaP ext ensively. Aqueous-soluble metabolites appeared to be eliminated very s lowly in M. viridis. Treatment with 3MC did not to enhance the rate el imination of parent compound, suggesting that metabolism of BaP was no t induced by exposure to 3MC. (C) 1997 Elsevier Science B.V.