Summary
Fuel spills have occurred in Antarctic and sub-Antarctic regions, and comprehensive remediation strategies have recently been established to clean-up fuel spills at Australia’s Casey Station and Macquarie Island. However, there are currently no environmental quality guidelines specific for Antarctic soils and the sensitivity of Antarctic flora and fauna to petroleum hydrocarbons is unknown. This research developed routine toxicity test procedures with native Antarctic terrestrial flora to guide remediation activities, with a view to establish remediation target concentrations for hydrocarbons using local flora, and for subsequent use in environmental risk assessments. The sensitivity and response of various native plant species to soil contaminated with Special Antarctic Blend (SAB) fuel was investigated using three Antarctic mosses, one Antarctic terrestrial alga, and seven Macquarie island grass and shrubs. Artificial soils with high and low organic carbon content were spiked with SAB fuel and used either immediately to represent a fresh fuel spill, or after two weeks to simulate an aged spill. Toxicity tests were performed for 21-28 days under controlled conditions (15°C; 16/8 hours photoperiod) to simulate growth conditions during Antarctic summer months. Several endpoints were investigated: photosynthetic efficiency, pigment content and visual health used for slower growing mosses and algae, and germination and root and shoot length investigated for faster growing grasses and shrubs. The early life stages of grasses and shrub identified that germination, and root and shoot length varied in response to fuel-contaminated soil, with root and shoot length exhibiting greater sensitivity than germination. Thus moss and algae may be under limited threat from present hydrocarbon contamination, however, future contamination from fresh spills are more problematic, particularly if the Antarctic climate continues to get drier. In general, fresh fuel was more toxic than aged fuel, with moss and algal communities eliciting tolerance to exposures up to 25,500 mgSAB/kg.
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