TP12 Toxicity of Complex Mixtures
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(KAN-1117-814904) Development of Novel Dose-Based Toxicity Benchmarks for Exposure of Fish to PAHs.

Kane Driscoll, S¹, Reiss, M.², Steevens, Jeffery³, ¹ Menzie-Cura & Assoc., Inc., Winchester, MA, USA² U.S. Environmental Protection Agency, New York, NY, USA³ U.S. Army Corps of Engineers, Vicksburg, MS, USA

ABSTRACT- Risk managers are eager to develop toxicity benchmarks that are based on concentrations of contaminants, such as PAHs, in fish tissue. However, because fish rapidly metabolize and eliminate PAHs, toxicity studies do not typically report concentrations of unmetabolized PAHs in tissue as a measure of exposure. The goal of this project is to develop a distribution of measures of exposure, other than tissue concentrations, that can be used to assess risk to fish from exposure to PAHs in sediment. The approach uses an uptake model to convert various measures of exposure reported in toxicity studies (e.g., concentrations of PAHs in food or water) to a common dose metric of mg PAHs taken up/kg fish/day. Collected data for various PAHs (e.g., dimethylbenz[a]anthracene, fluoranthene, phenanthrene, and benzo[a]pyrene) and fish species are used to develop a cumulative distribution function (CDF) of doses at which adverse effects occur (e.g., neoplasms, decreased growth, and biochemical effects) . The CDF may be used to identify doses of PAHs that are protective of a selected proportion of fish species. This dose-based benchmark will be compared to estimated dietary doses of PAHs for fish that consume invertebrate prey at dredged material disposal sites. The CDF will also be used to calculate the uncertainty associated with these protective levels. Issues, such as the application of Fish Potency Factors (FPF) to convert doses of individual PAHs to equivalent units of benzo[a]pyrene will be discussed.

Key words: PAHs, fish, sediment, Cummulative distribution function