Biotransformation and genotoxicity of fluoranthene in the deposit-feeding polychaete Capitella sp. I

Polycyclic aromatic hydrocarbons, such as fluoranthene (Flu), are of environmental concern because of their persistence, toxicity, and mutagenic properties. In this study we examined the genotoxicity of Flu to Capitella sp. I using the comet assay. We assessed patterns of DNA damage as a function of uptake route and as a function of exposure and depuration time and related levels of DNA damage to published information on Flu-metabolite formation. Exposure to approximately 30 μg Flu/g dry-weight sediment or 50 μg Flu/L seawater resulted in significant DNA damage. The degree of DNA damage was time dependent during both exposure and depuration, and although exposure route had no effect on the maximum degree of DNA damage occurring, it did influence the time course of damage. Levels of damage declined despite continued exposure to Flu, providing evidence for the induction of one or more DNA repair mechanisms. Comparison with Flu-metabolite profiles suggests that DNA damage is associated with the production of aqueous metabolites. The transitory nature of the DNA damage and repair process may contribute important insights into the mechanisms of toxicant effects at the molecular level but limits the usefulness of such endpoints as biomarkers of exposure or effect in ecotoxicological studies.