title: Nereis virens (Annelida: Polychaeta) is not an adequate sentinel species to assess the genotoxic risk (comet assay) of PAH exposure to the environment.
abstract: Polychaetes, because of their bioturbation capacity, play an important role in the distribution of anthropogenic contaminants (including polycyclic aromatic hydrocarbons [PAHs]) throughout the sediments. In this work the use of Nereis virens (Annelida: Polychaeta) as a bioindicator to assess the genotoxic risk of PAH exposure for the environment was evaluated. For this purpose the alkaline single cell gel electrophoresis [comet] assay was applied on the coelomocytes of in vivo exposed Nereis virens. Benzo[a]pyrene (B[a]P) was chosen because it is classified by the IARC (International Agency for Research on Cancer) as "probably carcinogenic to humans" and because its mechanisms of action are well-known. Nereis virens was exposed to B[a]P in concentrations of 0.3, 0.6, 10, 20, 35 and 45 mg/ml by an intracoelomic injection of B[a]P (20 microliters) dissolved in dimethyl sulphoxide (DMSO). A solvent control with DMSO, a positive control with ethyl methane sulphonate (EMS) (12.1 mg/ml) and a negative control were included in each experiment. For each treatment four animals were analysed. After 1 hr treatment coelomocytes were harvested by puncturing the coelomic cavity with a sharpened Pasteur pipette, mixed with 0.5% low melting point agarose and sandwiched between two other gel layers. Ethidium bromide stained nuclei were analysed for tail length and tail moment. 12.1 mg/ml EMS, pure DMSO (98.9%) and B[a]P in all tested concentrations induced a statistically significant increase of DNA single strand breaks in the comet assay. The effect of B[a]P, however, was only at the highest concentration (45 mg/ml) significantly stronger than the effect of DMSO alone. Although a relatively large heterogeneity in the results could be observed, these experiments clearly showed that Nereis virens is not suited as a sentinel species for the assessment of the genotoxic risk of PAH exposure because this species seems to be very resistant to benzo[a]pyrene.
authors.affiliation: Laboratory of Anthropagenetics, Free University of Brussels, Belgium. mdboeck@vnet3.vub.ac.be
authors.forename: M
authors.initials: M
authors.lastname: De Boeck
authors.forename: M
authors.initials: M
authors.lastname: Kirsch-Volders
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity; D004121:Dimethyl Sulfoxide / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects*; D004784:Environmental Monitoring; D005020:Ethyl Methanesulfonate / Q000633:toxicity; D007928:Lethal Dose 50; D051379:Mice; D009152:Mutagenicity Tests; D011077:Polychaeta / Q000187:drug effects* / Q000235:genetics*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D018570:Risk Assessment; D013045:Species Specificity
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D001564:Benzo(a)pyrene; D005020:Ethyl Methanesulfonate; D004121:Dimethyl Sulfoxide