Contamination in remote cold regions has only recently become a widely recognized problem. In the Arctic, extraction of oil and gas, mining, and disposal of nuclear wastes are well known sources of contamination in the ground.
Perhaps less well known is the legacy of old waste dumps in Antarctica associated with early exploration and the establishment of Antarctic stations. It is now acknowledged that historic practices of waste disposal in Antarctica, such as ‘sea-icing’ (dumping rubbish on the ice until it blows out to sea or the ice melts) or dumping waste in low-lying areas adjacent to the stations, has left a legacy of waste.
For Antarctica as a whole, the extent of contamination is much less than any other continent. But for a continent that is widely regarded as being of global environmental significance and a symbol of good environmental stewardship, any amount of waste and contamination needs to be carefully assessed and placed in the context of the unique Antarctic environment.
It is only very recently (1991) that the Antarctic Treaty nations, including Australia, agreed to a protocol (the Madrid Protocol) that established that past and present work sites should be cleaned up unless to do so would create a greater adverse environmental impact than leaving in its existing location or condition.
At present it is too early to tell how different Antarctic Treaty Nations will respond to the this obligation, or if they are financially or technically able to respond in a way that would satisfy the condition that clean-up should not lead to greater adverse environmental impacts.
Australia, as a leading Antarctic Treaty nation has taken this obligation seriously and has initiated ground breaking research and has embarked on a full-scale trial to clean-up abandoned waste sites in the Australian Antarctic Territory. But a cautious approach is required so that well-intentioned but poorly designed clean-up operations do not lead to increased contamination problems, even temporarily.
With this in mind, Australia is hosting the Third International Conference on Contaminants in Freezing Ground next week. The conference will promote exchange of scientific, technical and practical expertise in dealing with contaminants in freezing ground between northern and southern hemisphere scientists, environmental managers, industry stakeholders, and national Arctic and Antarctic operators.
One of the significant technological innovations that Australia will present at the meeting involves the development of a water treatment system for use in remote cold regions. Through a collaboration between Australian Antarctic Division scientists and engineers, researchers from the University of Melbourne, and the private company IntelEco, we have developed a pilot water treatment plant that will be taken to Casey station in Antarctica as part of the Australia’s to clean-up efforts.
One of the biggest problems we have to manage is the dispersal of unwanted contaminated water during site clean up operations. When excavation machinery begins to dig at a site, heavy metals such as copper, lead and zinc, in the rubbish and soil can easily become entrained by summer melt water and disperse from the site.
To prevent this transient contamination entering the nearby marine environment, we need to trap the water and process it to remove the contaminants. This is particularly challenging for the clean-up operation that is planned for Casey next season. Because of the volumes involved, it is too expensive to simply bring the water back to Australia for treatment, so it has to be treated on site in Antarctica. That limits the size of the plant we can develop to about 8 tons, which is the most that can be easily lifted at Casey.
Because the tip site at Casey, like other sites in Antarctica, is some distance from the main station, the water treatment plant must be have low energy requirements and be capable of running off a small generator. The materials need to withstand air temperatures of below -20C, but be able to process water at temperatures of only a few degrees when the snow melts. This places constraints on the types of technology that can be used because chemical reactions are often very sluggish at such low temperatures, and even fairly well established water treatment technologies need to be assessed for how well they cope with such cold temperatures.
This sort of applied research must underpin the design and optimisation of techniques for site management and remediation in cold regions, because clean up is inherently more difficult and expensive than elsewhere. The water treatment plant we have designed has been specifically built for the rigors of Antarctica but the reality is that the design will probably need refining during its trial operation because of the difficulties in predicting how these sorts of systems perform in the challenging Antarctic environment.
The key to success then is to have well-trained versatile people on hand to help solve problems as they arise to ensure that the operation achieves it’s goal - to reduce the amount of contaminants in freezing ground without causing greater adverse environmental impacts in the process of doing so.