Soil biogeochemical toxicity end points for sub-Antarctic islands contaminated with petroleum hydrocarbons

The purpose of the present study was to identify soil biogeochemical toxicity end points for petroleum hydrocarbon contamination in Sub-Antarctic soil. Soil from Macquarie Island, a sub-Antarctic island south of Australia, was collected end exposed to concentrations of Special Antarctic Blend (SAB) diesel fuel, ranging from 0 to 50,000 mg fuel/kg soil, for a 21-d period.

The sensitivity of nitrification, denitrification, carbohydrate utilisation, and total soil respiration to SAB fuel was assessed. Potential nitrification activity was the most sensitive indicator of SAB contamination assessed for nitrogen cycling, with an IC20 (concentration that results in a 20% change from the control response) of 190 mg fuel/kg soil. Potential denitrification activity was not as sensitive to SAB contamination, with an IC20 of 950 mg fuel/kg soil for nitrous oxide production.