Identifying naturally occurring radioactive materials (NORM)
such as radon and uranium in groundwater should form an
important component of baseline research prior to unconventional
gas development. Groundwater radon concentrations
(0.14e20.33 Bq/L) and groundwater uranium levels (0.001 and
2.77 mg/L) were highly variable across the catchment and were well
below the Australian Drinking Water Guideline values (radon;
100 Bq/L and uranium; 17 mg/L). Radon samples higher than 10 Bq/L
(n ¼ 5) were from the basalt units. The Lismore Basalt had low
uranium concentrations (0.04 mg/L) yet relatively high radon activities
(7.88 Bq/L) likely due to recoil and increased radon migration
in the highly vesicular and fractured rocks, resulting in a
decoupling between radon activities and uranium concentrations.
A positive correlation between U and HCO3
(r2 ¼ 0.49, p < 0.01)
indicated uraniumwas present in uranylecarbonate complex forms
in the Quaternary Sediments aquifers. Reduced conditions and low
uranium concentrations in theWoodburn Sand aquifer implied the
presence of the sparingly soluble uraninite. However, therewere no
correlations between uranium and radon for the entire dataset or
individual geological units. Monitoring radon and uranium activities
in groundwater may contribute to detecting potential long
term chemical changes in CSG production areas