Aliphatic hydrocarbons in sediments: a chronic toxicity study with winter flounder (Pleuronectes americanus) exposed to oil well drill cuttings

Most studies on the chronic toxicity of hydrocarbons have focused on the polycyclic aromatic component; however, information is also required on the chronic toxicity of ether classes of hydrocarbons. This need has been brought to the forefront by the controversy about the use of aliphatic hydrocarbon-based drilling fluids at petroleum development sites in the marine environment. Dose-response relationships were studied for a variety of indices in a chronic toxicity study with winter flounder (Pleuronectes americanus) exposed to sediments contaminated with drill cuttings enriched in hydrocarbons. The indices investigated were biologically meaningful and included organ and body condition indices, muscle and liver energy reserves, mixed-function oxygenase detoxification enzymes, blood parameters, and liver and gill histopathology. There was no evidence of dose-response relationships and most indices remained unaffected even at the highest exposure level. The study supports the hypothesis that the aliphatic component of complex hydrocarbon mixtures is relatively nontoxic, and it will be of particular interest for evaluating the scope of environmental risks associated with the use of oil-base drilling fluids in the marine environment.