Ecotoxicological endpoints for contaminated site remediation.

Use of chemical criteria in assessing the potential for adverse toxic effects in contaminated sites can under or overestimate the necessary level of site cleanup required. The use of ecotoxicity testing provides a more direct assessment of adverse environmental impact. A multi-trophic level soil ecotoxicity assessment was done on soil contaminated with crude oil distilled into five different fractions based on hydrocarbon chain lengths. Results indicate that the fraction above C26 was not toxic to microbes, plants, and earthworms, when present in concentrations far above the 1000 mg/kg total petroleum hydrocarbon criterion. Our ecotoxicity test battery results indicate that weathered heavy crude oils can be much less toxic than lighter, freshly spilled diesel oils, yet using a gross measure of total petroleum hydrocarbons would not detect this differences.