What is a Safe Level of Polycyclic Aromatic Hydrocarbons for Fish: Subchronic Toxicity Study on Winter Flounder (Pseudopleuronectes americanus)

Dose–response relationships were evaluated for a variety of biological and biochemical indices in a subchronic toxicity study with winter flounder (Pseudopleuronectes americanus) exposed to sediments contaminated with a petroleum source of polycyclic aromatic hydrocarbons (PAH). Indices investigated were biologically meaningful and included muscle and liver levels of energy reserves, organ weight – body weight relationships, and general condition indices. Results support the hypothesis that many point sources of sediment hydrocarbon contamination worldwide could be harmful to fish health. Biochemical effects such as change in mixed-function oxygenase (MFO) enzyme levels and fat content of liver were altered at very low hydrocarbon levels (~1.0 μg/g), levels that we reason will likely be found in sediments over much wider geographical areas than polluted harbors, or oil development and sewage outfall sites. We hypothesized that hydrocarbons in both coastal waters and food species may often occur in sufficient concentrations to affect biological responses in fish. The fact that very low levels of hydrocarbons in sediments, water, or foods may produce biological responses in fish attests to the importance of developing criteria for assessing the toxicological significance of sublethal effects or otherwise defining genuine harmful effects in contrast with effects per se.