Monitoring radiation exposure in Kakadu

Some of the bush tucker found in Kakadu.

 

 

 

 

 

 

 

Welcome to Part Two in a two-part feature on radon, a chemical element associated with radiation.

SCIENTISTS from Supervising Scientist are tasked with monitoring radiation levels in the Alligator Rivers Region, to make sure that the environment and people are protected from radiation arising from uranium mining.

Radon, for example, is a naturally occurring radioactive gas that is emitted from soils, natural rocks and also from uranium ore that is stockpiled on the Ranger mine site. Most radon stays in the ground or rocks, but some escapes into the atmosphere and is spread around naturally by the wind. Breathing in radon gas is harmless, however, radon decays into different metals, known as ‘radon progeny’, and these can be inhaled and then stay within the lungs.

Radioactivity levels in dust are very low but breathing dust is also a way in which people can be exposed to radiation. For these reasons, radiological monitoring of the air for radon progeny and dust occurs all year round just west of Mudginberri community, in the town of Jabiru and at the Supervising Scientist’s Jabiru field station. To date the levels of radon gas and progeny measured have been low, and consistent with natural levels.

There are two additional ways a person can be exposed to radioactivity: through ingestion and through external radiation (gamma radiation).

Bush foods naturally incorporate some radioactivity from the environment

Bush tucker such as fish, mussels, wallaby, yams and buffalo make up part of the diet of people living near Ranger mine, and these bush foods naturally incorporate some radioactivity from the environment. Ingestion of this radioactivity can be of concern, in particular in mussels, which naturally accumulate heavy metals and radioactivity as part of their feeding and digestion processes. Therefore, mussels are regularly tested by our scientists. Although samples have been collected in the region over many years, no significant change to radioactivity levels has occurred downstream of the mine, since mining began in 1981.

People can also be exposed to radioactivity from external sources, for example by walking on areas that have higher radioactivity levels. Post-production rehabilitation plans for Ranger mine site include plans to push soil back on top of the old pits and tailings dam and revegetate the decommissioned site to minimise the risks of external exposure and air-borne dust being inhaled, and limit the amount of radioactivity getting into the surrounding environment.

Water and air monitoring results for the Ranger and Jabiluka sites are available on the Department of the Environment website.

Supervising Scientist conducts research on the impact of uranium mining on the environment of the Alligator Rivers Region. Questions? Call us: 08 8920 1100

From the pages of The Monitor, the Supervising Scientist’s ARR monitoring update.

In Part One of this two-part feature we looked at naturally occurring radon gas, Radon Springs in Kakadu National Park, and radon in history.