Radon-222 concentrations in potable groundwater in Australia

A considerable amount of controversy exists concerning the level, or even necessity, of drinking water guidelines for dissolved radon-222. Radon-222 has a half life of 3.8 days, and has been the subject of a great deal of research in North America and Europe with respect to its contribution to indoor radon gas concentrations where water is sourced from groundwater supplies. Because radon readily escapes when in contact with the atmosphere, radon-222 in surface water supplies is usually negligible. In 1981, the US EPA suggested an interim maximum permissible level of 11 Becquerels/Litre (1 Bq/L = 1 disintegration per second), although this was later revised to an 'action level' 147 Bq/L pending a National Academy of Sciences Toxicity Assessment of drinking water radon. The current Australian ARMCANZ/NHMRC recommended value is 100 Bq/L, which is more in keeping with European standards. This study set out to measure radon-222 concentrations in some of Australia's groundwater supplies, as well as assess any areas or lithological aquifer types that may have high radon concentrations.