Summary
There have been a number of fuel spills (diesels and lubricating oils) on sub-Antarctic Macquarie Island associated with fuel storage and power generation for the island’s research station. The Australian Antarctic Division is currently working to remediate these sites over the next 5-10 years. In order to develop appropriate target levels for remediation, this study examines the response of soil invertebrates to Special Antarctic Blend (SAB) diesel. As organic carbon is known to play a crucial role in determining the bioavailability of organic contaminants in soils, the response of invertebrate communities to SAB was examined in 20, one m² plots across a natural organic carbon gradient with total organic carbon (TOC) ranging from 0 to 50%. Vegetation cover was determined and 7 pairs of soil cores (75 mm wide x 70 mm deep) sampled from each plot. Pairs of cores were spiked with SAB by injection (control and 6 target concentrations between 500 and 40000 mg/kg) and kept in growth cabinets under field-simulated conditions (8°C, 16 h light / 8 h dark). After 10 days exposure, surviving invertebrates were removed from one of each of the paired cores using a high temperature gradient extraction cabinet. Invertebrates were counted and identified to species (Collembola), genus or to the family level. Remaining cores were analysed for physical and chemical properties including total petroleum hydrocarbons (TPH), TOC, nutrients, moisture content and particle size. Community assemblage response to SAB contamination and interactions with TOC and other physical and chemical variables were determined. This work contributes to a multi-national project investigating hydrocarbon contamination in cold region soils aimed at developing site specific clean-up and remediation guidelines based on contaminant concentration and soil composition and chemistry.
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