title: Additive toxicity of binary mixtures of phototoxic polycyclic aromatic hydrocarbons to the oligochaete Lumbriculus variegatus.
abstract: Toxicity of some polycyclic aromatic hydrocarbons (PAHs) can increase by an order of magnitude, or more, in the presence of solar ultraviolet (UV) radiation. In the environment, PAHs exist as complex mixtures, which generally would include multiple PAHs that could cause photoinduced toxicity. Hence, to accurately predict the potential ecological risk of phototoxic PAHs, it is critical to understand their joint toxicity. In this study, we exposed the oligochaete Lumbriculus variegatus to the phototoxic PAHs anthracene, fluoranthene, and pyrene, both singly and as binary mixtures for 96 h. Following this, the animals were exposed to UV light for an additional 96 h, during which periodic observations of mortality were made. Time-dependent phototoxicity of the binary PAH mixtures, expressed as a function of the product of UV light intensity and PAH dose (in the tissue of the animals), was adequately described using a concentration addition model. Given the probability that the PAHs examined acted via a common mechanism of action, this result was consistent with expectations. These data highlight the need to consider the combined photoactivation potential of PAH mixtures and provide the technical basis for a modeling approach to predict their ecological risk.
authors.affiliation: National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Duluth, Minnesota, 55804, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Erickson
authors.forename: G T
authors.initials: GT
authors.lastname: Ankley
authors.forename: D L
authors.initials: DL
authors.lastname: DeFoe
authors.forename: P A
authors.initials: PA
authors.lastname: Kosian
authors.forename: E A
authors.initials: EA
authors.lastname: Makynen
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000008:administration & dosage / Q000633:toxicity; D005449:Fluorenes / Q000008:administration & dosage / Q000633:toxicity; D009835:Oligochaeta / Q000187:drug effects*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D011721:Pyrenes / Q000008:administration & dosage / Q000633:toxicity; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D000873:Anthracenes; D005449:Fluorenes; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; C007738:fluoranthene; C030984:pyrene; C034020:anthracene