title: Effects of Nereis diversicolor on the transformation of 1-methylpyrene and pyrene: transformation efficiency and identification of phase I and II products.
abstract: Transformation of nonsubstituted and alkyl-substituted polycyclic aromatic hydrocarbons (PAHs) by the benthic invertebrate Nereis diversicolor was compared in this study. Pyrene and 1-methylpyrene were used as model compounds for nonsubstituted and alkyl-substituted PAHs, respectively. Qualitative and quantitative analyses of metabolites and parent compounds in worm tissue, water, and sediment were performed. Transformation of 1-methylpyrene generated the benzylic hydroxylated phase I product, 1-pyrenecarboxylic acid that comprised 90% of the total metabolites of 1-methylpyrene, and was mainly found in water extracts. We tentatively identified 1-methylpyrene glucuronides and 1-carbonylpyrene glycine as phase II metabolites not previously reported in literature. Pyrene was biotransformed to 1-hydroxypyrene, pyrene-1-sulfate, pyrene-1-glucuronide, and pyrene glucoside sulfate, with pyrene-1-glucuronide as the most prominent metabolite. Transformation of 1-methylpyrene (21% transformed) was more than 3 times as efficient as pyrene transformation (5.6% transformed). Because crude oils contain larger amounts of C₁-C₄-substituted PAHs than nonsubstituted PAHs, the rapid and efficient transformation of sediment-associated 1-methylpyrene may result in a high exposure of water-living organisms to metabolites of alkyl-substituted PAHs, whose toxicities are unknown. This study demonstrates the need to consider fate and effects of substituted PAHs and their metabolites in risk assessments.
authors.affiliation: Department of Environmental, Social and Spatial Change, Roskilde University, Universitetsvej 1, PO Box 260, DK-4000 Roskilde, Denmark. lmvm@ruc.dk
authors.forename: Linus M V
authors.initials: LM
authors.lastname: Malmquist
authors.forename: Jan H
authors.initials: JH
authors.lastname: Christensen
authors.forename: Henriette
authors.initials: H
authors.lastname: Selck
mesh_terms: D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D006900:Hydroxylation; D011721:Pyrenes / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011721:Pyrenes; C030984:pyrene; C053035:1-methylpyrene