Landholders in Queensland are calling on the state government to find the cause of methane gas bubbling in a major river, which they say has intensified in recent months.
The so-called methane seeps in the Condamine River near Chinchilla were reported in 2012, triggering a series of investigations.
But the government has told the ABC that it does not have sufficient information to identify the cause of the seeps.
Professor Damian Barrett, the CSIRO’s lead researcher into unconventional gas, has been monitoring the Condamine gas seeps.
He confirmed to the ABC that the bubbling had intensified.
“There have been changes in the flux of methane through the river over the past 12 months,” he said.
The ABC visited the most prominent methane seep in the river about six kilometres west of the Chinchilla weir, observing large, concentrated bubbles rising to the water’s surface.
“From what I’ve visually seen since the first videos back when they were originally found, they were just minor bubbles in particular locations,” said Helen Bender, whose family owns two properties near the Condamine.
“In terms of the number of bubbles along the river, both upstream and downstream, [it] is increasing.”
A 2013 report by scientific analysis firm Norwest Corporation outlined several “scenarios” which could be contributing to the bubbling in the river.
These included natural events such as drought and the recharging of aquifers after floods.
Human activity such as coal seam gas (CSG) operations and water bore drilling were other possible contributing factors.
“We know that methane is coming to the surface along a fault line, a very small fault line that occurs and intersects with the river,” said Professor Barrett, who is also the director of the Gas Industry Social and Environmental Research Alliance, a partnership between the CSIRO and the CSG industry.
“We know that the methane that is bubbling in that river is varying in time and the reason for that – while it is unknown – could be perfectly natural.”
Origin Energy, which operates CSG wells in the district, is monitoring the bubbling in the Condamine.
“I have to question if Origin is doing the ongoing monitoring, why isn’t more of an independent person doing the ongoing monitoring so that there’s some real transparency with what’s actually happening?” Ms Bender said.
Western Darling Downs landholder and anti-coal seam gas activist John Jenkyn said the bubbling had worsened since the arrival of the CSG industry.
“I think [it’s] the de-watering. As [the CSG companies] take all the water out of the wells I presume the gas has found the easiest route out of the ground, which happens to be in the river. So up she comes,” he said.
A Queensland government report released in December 2012 found that the cause of the bubbles was “unlikely to be determined in the short-term, and that a long-term approach to find more science-based answers to the phenomenon was needed”.
“I think there’s a lot missing in those [methane seep] reports which we need to know the answers to now, because the bubbles are getting worse as the CSG activities continue,” Ms Bender said.
A spokesman for Queensland’s Department of Natural Resources and Mines confirmed that there was “currently insufficient information to identify the cause of the gas seeps” and that further investigation was warranted.
“Geological complexity and the requirement to gather and analyse surface and subsurface data make this a long-term investigation,” the spokesman said.