Throughout the world, attitudes towards the environment have changed markedly over the last thirty to forty years. Nowhere is this more obvious than in Antarctica. In the past, consistent with contemporary attitudes towards the environment, it was accepted practice to dispose of waste from Antarctic stations by dumping in convenient low-lying areas. Disposal also commonly involved pushing rubbish on to the sea-ice ('sea-icing') so that it would be dispersed as the ice broke up in summer. As a consequence, many stations in Antarctica now have large abandoned waste disposal sites, some of which extend into the marine environment. Unfortunately the types of materials that were disposed of in this way are sources of contamination that are persistent in the environment. Although it is no longer accepted practice to dump waste in the Antarctic, and all Australian rubbish is now returned to Australia, contamination from old sites still spreads each year into environmentally sensitive areas where impacts can occur. To begin the process of cleaning up the legacy of contamination in Antarctica, the Australian Antarctic Division has established a Contaminated Sites Taskforce to oversee the clean-up of abandoned waste disposal sites. Before clean-up can proceed, three key questions need answers:
- What are the practical options for remediation of abandoned waste under Antarctic conditions?
- What is the current impact of these sites?
- How should we monitor to ensure that removal does not cause greater adverse environmental impact?
Together these questions are the focus of research by the Human Impacts Program at Casey station this year. Casey was chosen because it includes two old stations and their waste disposal sites — Wilkes (1957–69) and Old Casey (1969–88). One of our highest priorities is to clean up the abandoned station and waste at Wilkes. But before we do that we need to undertake research on a smaller scale to perfect our methods.
The Old Casey tip in Thala Valley has been chosen as a stepping stone in the lead up to Wilkes and other sites. It was chosen because the tip is relatively small (~2500m3) and because it was disturbed during recent attempts to clean-up in 1995–1996. The site in Thala Valley will be used as a case study to investigate the processes of contaminant dispersal, remediation treatment design and performance, and chemical and biological monitoring. Research in Australia this year will focus on improving pilot-scale water treatment technologies that were tested in Antarctica in 2000–2001. These technologies aim to remove contaminants from snow that melts in the tip and that cannot otherwise be diverted. To complement this work, the field team at Casey will be developing chemical and biological monitoring techniques prior to the disturbance that will be associated with clean-up of Thala Valley — which is planned for 2002–2003. This will enable real-time feedback as the clean-up progresses and will help ensure that contaminants are not released into the environment when the tip is removed.
The process of cleaning up the tip will enable us to develop techniques in a controlled way before attempting much larger sites, such as those at Wilkes. A cautious approach is necessary to ensure that a well intentioned but poorly designed clean-up does not cause greater environmental impacts than leaving sites untouched.
Martin Riddle and Ian Snape
Human Impacts Research,
Australian Antarctic Division