Gas leaks spark call for probe
COAL seam gas fields around Tara in Queensland's Darling Downs are leaking radon gas at levels three times higher than non-CSG zones, new research from Southern Cross University has found.
Published in the international journal Environmental Science and Technology and available online, the paper is the first peer-reviewed study in Australia reporting the potential influences of CSG on the chemistry of the atmosphere.
Radon is a radioactive gas and is naturally and continuously emitted from the ground and rapidly dissipates, making it an excellent tracer for scientists to observe changes in soil structure.
When disrupted, soils release far higher levels of radon than normal, for example during earthquakes or from human activities such as mining.
"Coal seam gas drilling is about enhancing gas pathways by reducing water pressure and creating fractures in the soil, either through drilling or hydraulic fracturing, and we hypothesize that both of these processes would increase the release of radon as well," the paper's lead author Douglas Tait said.
The higher presence of radon may signify the release of other gases such as methane through the same pathways in the soil.
This connects the paper with research released last year (yet to be peer-reviewed) which showed methane levels in the air around Tara were three times higher than normal.
Co-author Dr Damien Maher said the findings suggested leakage from gas pathways in the soil had yet to be accounted for.
Emissions from gas wells are currently recorded but not the general area around gas operations.
"Fixing the infrastructure is relatively easy. Fixing up the changes in the soil structure is much more difficult," Dr Maher said.
"Methane, for instance, is 100 times more powerful than carbon dioxide as a greenhouse gas, and if there are unidentified pathways for methane release this can have significant ramifications for greenhouse gas budgets."
The researchers have called for urgent baseline studies across areas slated for coal seam gas extraction to track the changes in atmospheric chemistry as CSG activity increases.