Summary
Special Antarctic Blend (SAB) is a light end diesel fuel, comprised mainly of petroleum hydrocarbons (alkanes nC9-C14, trace levels of nC15-23). It is used as the main source for power generation at Australia’s Research Stations in Antarctica and the subantarctic, including Macquarie Island. Three major spills have occurred on Macquarie Island associated with storage of SAB between 1994 and 2002. In situ remediation of these contaminated sites commenced in 2009. This study investigates the sensitivity of native plant species to total petroleum hydrocarbons (TPH) in soils, using seed germination based toxicity testing. In the summer field season of 2012/13, native seeds were collected from various uncontaminated sites on the island. Seeds from five different target species that are common to the spill sites were exposed to 0 – 25 000 mgSAB/kg dry soil. Both a sandy soil (representative of soil at the spill sites) and a standard soil mix (based on Environment Canada guidelines) were spiked with SAB and aged for 2 weeks in the dark at 15°C. Actual TPH concentrations in the spiked soils were determined using Gas Chromatography – Flame Ionisation Detection (GC-FID). Germination bioassays were performed at 15°C on a 16:8 h light:dark cycle over 21 days. Germination was deemed successful upon the emergence of the radicle (root) and/or epicotyl (stem). This study will identify the threshold tolerance concentrations of TPH for seed germination of a range of native plants from Macquarie Island. Data obtained will inform and direct remediation activities by providing protective end points for contaminated sites.
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