Summary
One of the serious threats to the Antarctic marine ecosystem is the release of large volumes of petroleum fuel. Numerous fuel spill incidents have occurred and risks of a major spill are increasing due to continued expansion of human activity in the Antarctic region. The sensitivities of Antarctic marine organisms to pollution are largely unknown, and water quality guidelines for management of hydrocarbon contamination in Antarctic marine waters have not been developed. To address this knowledge gap, toxicity tests were conducted on a range of marine invertebrates, including the amphipod Paramoera walkeri, at Davis and Casey Stations. Three fuels were mixed with cold seawater to generate water accommodated fractions (WAF) of Special Antarctic Blend (SAB) diesel, Marine Gas Oil (MGO) diesel and intermediate fuel oil (IFO 180). Adult and juvenile amphipods were sensitive to WAFs of all three fuels. Amphipod mortality and total hydrocarbon concentrations were highest in SAB WAFs compared to the MGO and IFO. Results showed differing responses between life-stages and over time, and sub-lethal effects occurred at lower concentrations than did mortality in WAFs of all three fuels. Point estimates of the concentration of hydrocarbons in WAFs causing mortality (LC5 and LC50) and behavioural effects (EC5 and EC50) to 5% and 50% of test organisms were derived. These results can be used to assess the potential risk of fuel contamination on Antarctic marine invertebrates, to develop spill contingency plans, and will provide a scientific basis for better management of fuel carriage and transfer in the Antarctic.