The lowest observed effect concentrations (LOECs; lowest treatment concentration that is statistically different from the control exposure) for PAHs frequently occur in the low part per billion (ppb; ngml-1) range for water concentrations and the low part per million (ppm; mg g~ ) or high ppb range for sediment/soil and dietary concentrations. LOECs are generally applied to sublethal toxicity tests; however, they can be used to express a low percentile for the lethality response. Several recent review articles provide summary data showing biochemical, histopathological, immunological, genetic, reproductive, and developmental effects due to PAH exposure in a variety of species exposed to individual PAHs and mixtures by several methods (e.g., water, sediment, dietary, and injection).
A number of review articles report a wide range in the administered dose (0.04-3300 mg/gbw) causing adverse effects for lab animals and wildlife that are species and compound specific. Consequently, this variability precludes any generalizations that can be made about sublethal toxic responses to PAHs. Because PAHs are readily metabolized by most species, there are very few established tissue concentrations associated with sublethal responses that could be used to determine a threshold concentration for environmental protection.
Was this article helpful?