Contaminated sites and pollution
Contaminated waste disposal is a product of past practices of Antarctic expeditions, and is referred to as legacy contamination. Before the Madrid Protocol was signed in 1991, rubbish was dumped at various locations near the stations, or was disposed of by leaving it on the sea ice until it broke out.
Because of past practices, waste material is present in the terrestrial and nearshore marine environments. Some contaminants are known to be present in quantities that are potentially hazardous to the environment. Although frozen for much of the year, these contaminants can be mobilised during the summer months when there is increased water flow through areas from the snowmelt.
The largest ongoing risk and source of new pollution in Antarctica is associated with bulk fuel storage. Large quantities of SAB fuel (more than 1 million litres per year) is transferred from the ship and stored at the stations. The climate in Antarctica presents significant challenges for infrastructure and operations, and there is always the risk of spills when transporting or storing fuel. Land-based fuel spills, some as large as 11,500 litres, have occurred in the past 5 years, because of mechanical failures or human error during transfer from ship to shore. A review of spill incidents from the 1980s to 2013 identified:
- 1 spill of more than 100,000 litres (234,000 litres from MV Nella Dan sinking off Macquarie Island in 1987)
- 6 spills of 10,000–90,000 litres
- 10 spills of 1000–9000 litres
- 6 spills of 200–900 litres
- 32 spills of less than 200 litres.
Approximately 65 per cent of spills are the result of equipment or mechanical failure, and the remaining 35 per cent are because of human error. In some instances, fuel storage tanks leaked during winter, and the leaks went unnoticed until the summer melt revealed that they had drained their contents. Today, all tanks are bunded (surrounded by a secondary containment that minimises or eliminates any fuel leakage). Hence, the environmental damage is reduced or avoided altogether.
Recently, several tip sites and old fuel spill sites have been assessed and remediated, including the Casey tip site. The most significant fuel spill remediation under way at the time of writing is at Casey Station; in late 2015, a connection in the fuel transport infrastructure leaked and contaminated the site. This incident is the subject of an investigation, and a comprehensive risk assessment has been conducted to identify the best course of action in containing and remediating the site.
The AAD has successfully remediated soils contaminated from several fuel spill events, and used remediated soils in building projects at Davis (Box ANT8) and Casey stations.
Some station buildings contain asbestos, and the AAD has started to identify how to address this. For example, asbestos removal from the former living quarters at Davis Station resulted in a significant amount of asbestos being returned to Australia in 2015. Other areas, such as Heard Island, present a greater challenge. The decay of buildings and structures, and the extent of asbestos debris on the island was assessed in 2012. However, there has not yet been an opportunity to undertake any clean-up activity at the site of the former Australian National Antarctic Research Expeditions station at Atlas Cove on Heard Island. The AAD provides warning and advice to government and nongovernment operators that intend to visit the site, as part of the assessment and authorisation process provided for in the Heard Island and McDonald Islands Marine Reserve Management Plan, and the Environment Protection and Management Ordinance 1987 to the Heard Island and McDonald Islands Act 1953.
Despite the large distances that separate Antarctica from the rest of the world, pollution generated elsewhere on Earth can travel to Antarctica by air or water. Some persistent organic pollutants, such as the insecticide DDT and its derivatives, can be transported to the polar regions through a process known as ‘global distillation’. This process occurs when volatile chemicals evaporate in the warmer places in which they are used and condense in colder places.
Antarctica provides an important site for monitoring global background levels of known contaminants that are controlled by the Stockholm Convention on Persistent Organic Pollutants. Antarctica also serves as an early warning of the global environmental build-up of new and emerging contaminants.