Monitoring and remediation of hydrocarbon contamination at the former site of Greenpeace's World Park Base, Cape Evans, Ross Island, Antarctica

摘要

This paper describes the results of a program for the monitoring and remediation of hydrocarbon contamination at the former Greenpeace base site, located at Cape Evans, Ross Island, Antarctica (77°38′S, 166°24′E). World Park Base operated year-round between 1987 and 1991. It was entirely removed in 1991-92. Increased levels of hydrocarbons occurred in sediments nearby the base. The total volume of fuel spilt during Greenpeace operations, estimated at less than 200 L, was less than what would now require reporting according to existing guidelines for national programs. Some fuel spills might have predated Greenpeace activities. Hydrocarbon contamination was highly localised and largely contained in the active layer. However, in one site hydrocarbons were detected to a depth of 70 cm into the permafrost. Low impact, low technology remedial action applied at some sites removed a significant percentage of fuel in the active layer, thus reducing the potential for secondary effects. The fuel that remains in the subsurface post-remediation, estimated in the order of some tens of litres, is contained in 'lenses' of contaminated sediment at the bottom of the active layer. These subsurface hydrocarbons may mobilise into the backfill cover above or in the upper part of the permafrost. Hydrocarbons were detected in previously uncontaminated backfill, which may have resulted from upward migration and re-deposition of hydrocarbons. During the monitoring period the interaction of contaminated sites with meltwater and aeolian processes did not significantly change the hydrocarbon distribution at spill sites, although limited mobilisation of hydrocarbons is likely to occur by these or other mechanisms. The difficulty of removing hydrocarbons from permafrost terrain underscores the legal (under the Protocol on Environmental Protection to the Antarctic Treaty) and ethical responsibility of all operators to avoid their release into the Antarctic wilderness, including the areas that have been subject to earlier impacts. A no-action approach might in some cases be the best option available to deal with contaminants in freezing ground, but it is not acceptable unless it is preceded by the thoughtful consideration of all other alternatives. Ultimately, there is a need to find environmentally friendly alternatives to using fossil fuels as the primary source of energy in Antarctic stations.