Radioactivity in Helidon spa waters

The spa water area near Helidon, Queensland has been historically used for the commercial supplies of mineral water. Many bores are still in use, generally for cattle feeding. The hydrogeology of the area is complex. The spa water aquifer system is located at the junction of two geological units differing in age and formation. Results of 18O and 2H measurements of the spa water indicates the water originates from the aquifers of the Great Artesian Basin. The 226Ra activity concentrations of the spa waters, determined by a special liquid scintillation counting technique, lie in the range 0.5 -1.3 BqL-1 exceeding the recommended drinking water guidelines for livestock. At one site the overland flow and ponding of water has improved the water quality through the sorption of radioactivity onto the sediment. Further research is in progress on the potential benefits of this natural filtration method. (author)