Radon detection in Antarctica

OUR ENVIRONMENT Radon detection in Antarctica

An Australian-Korean collaboration

While Antarctica remains one of the cleanest places in the world, increasingly large amounts of natural and man-made atmospheric pollutants are finding their way to the frozen continent. Pollutants enter via a number of pathways; some direct, others more convoluted.

Since 2012, ANSTO researchers have been collaborating with the Korea Polar Research Institute (KOPRI) to identify and characterise the source regions of anthropogenic pollution making its way to Antarctica from distant continents, and to determine the fate and impact of this pollution when it arrives.

The main investigative tool to track the pollution back to its source regions is the naturally-occurring radioactive gas radon (222Rn). Radon is emitted continuously from all soils and rock (i.e. ice-free land surfaces), with almost none coming out of the ocean. Due to its short radioactive half-life of 3.8 days, radon levels decay away almost completely within 20 days after emission. By measuring the radon concentration of an air mass arriving at Antarctica, researchers are able to deduce the degree of land contact it has had over the past two-to-three weeks, and therefore the pollution sources to which it may have been exposed.

An ANSTO-built radon detector has been operating since February 2013 at the Korean-owned King Sejong station on King George Island, at the fringe of Antarctic territory (62°S). Furthermore, in December 2015, a second ANSTObuilt radon detector was installed at the newly-established Korean base at Jang Bogo Station in Terra Nova Bay (75°S) on the Antarctic mainland.

Measurements from these radon detectors, together with a comprehensive suite of aerosol and trace gas monitoring equipment operated by KOPRI, are being used to gain a better understanding of pollution pathways all the way into the Antarctic heartland, more than 3000 km from the nearest continent.

The radon detector at King Sejong station is part of a global suite of radon detectors operated by ANSTO as a contribution to the World Meteorological Organisation’s Global Atmospheric Watch (WMO-GAW) program. ANSTO’s unique technology for highly sensitive measurements of atmospheric radon is recognised by WMO as the best in the world for global and regional atmospheric composition baseline studies.

Other key WMO-GAW stations featuring ANSTO radon measurements include Cape Grim in Tasmania, Mauna Loa Observatory in Hawaii, Cape Point Observatory in South Africa, Gosan Island in South Korea, Jungfraujoch in the Swiss Alps and Baring Head in New Zealand. As an unambiguous tracer of terrestrial influence on air mass composition, radon is an essential component of baseline studies for: selection of least terrestrially perturbed marine air masses; tracing and analysis of air mass history and fetch; calibration / constraint of regionally-integrated emission estimates for important distributed trace gases; and evaluation of transport and mixing schemes in climate and chemical transport models.

ANSTO also operates radon detectors at Macquarie Island and aboard the new Australian National Marine Facility RV Investigator. Together, this network of detectors represents a unique tracer facility for aiding the characterisation of sources and movement of atmospheric pollutants in the Southern Ocean region.

Contact

scott.chambers@ansto.gov.au

COLLABORATORS

1

ANSTO

RESEARCH FACILITY / TECHNIQUE

Isotopic tracing techniques

2

Korea Polar Research Institute (KOPRI)

King George Island

RESEARCHER TEAM

Dr Scott CHAMBERS

Dr Sangbum HONG Dr Alastair WILLIAMS

1

2

1

PUBLICATIONS

Atmospheric Chemistry and Physics 2014 Aerosol Air Quality Research 2016