SCU releases CSG baseline atmospheric and groundwater studies

New internationally peer-reviewed research from Southern Cross University has provided some of the first Australian baseline methane datasets for atmospheric and groundwater chemistry, giving a snapshot that will enable future comparisons.

The air and groundwater samples collected in two separate studies showed no evidence of methane gas leaking naturally from coal seams in the Richmond River catchment (extending from the Byron Shire in the north, Evans Head in the south, and west to Casino and Kyogle) where decommissioned exploration wells are in place but production has not yet commenced.

The research has appeared in separate journals: the just-published ‘Seasonal and diurnal dynamics of atmospheric radon, carbon dioxide, methane, δ13C-CO2, and δ13C-CH4 in a proposed Australian coal seam gas field in Water, Air, & Soil Pollution and recently, ‘Groundwater methane in a potential coal seam gas extraction region' in the Journal of Hydrology: Regional Studies.

The study on atmospheric chemistry, led by Dr Douglas Tait, measured atmospheric trace gas concentrations near Casino over a period of one year. Dr Tait focused his research on the Dobies Bight area north-west of Casino where there are inactive exploration wells.

“We measured atmospheric radon, methane and carbon dioxide concentrations to look at how these gases are currently being released to the atmosphere,” Dr Tait said.

“All evidence points towards natural processes controlling atmospheric methane concentrations in the region.

“Factors such as the time of day, season and the amount of rain all influenced the measured gas concentration. Therefore future programs designed to capture baseline data must be done over the long term.”

A separate groundwater study provided crucial baseline information on groundwater chemistry in an area earmarked for future CSG extraction. Leading that study was PhD candidate Marnie Atkins.

“To assess the impacts of any development on the environment we need to know the conditions prior to that development, we need baseline data,” said Ms Atkins.

“We measured groundwater chemistry from 91 groundwater bores throughout the Richmond River catchment, with a particular focus on methane, the dominant gas in CSG. The aim was to provide a snapshot of existing groundwater chemistry that will allow future comparisons to be made against.

“We found no evidence of methane moving from the coal seams into the overlying groundwater. Overall, we found good groundwater quality throughout the catchment,” she said.

Dr Damien Maher, co-author of both papers, said the findings revealed that more work needed to be done.

“While these two studies put us in a better position to assess long term impacts, we sampled only existing groundwater bores, and our atmospheric monitoring was limited to one area.

“Ideally, new groundwater monitoring bores should be drilled at strategic locations near CSG wells, and atmospheric monitoring should be undertaken across a range of locations,” said Dr Maher.

Professor of Hydrogeology Isaac Santos said the studies relied on the support of landholders who allowed SCU researchers onto their properties to sample groundwater bores and install atmospheric monitoring equipment.

“We were amazed at the level of community support for this project. Ms Atkins led the fieldwork activities where we sampled about five groundwater bores per week. Additional bores could not be sampled due to timing constraints. This was a great example of how SCU engages with the local community, and vice versa,” he said.

“Community members whose properties were involved in the study have been sent detailed information on the chemical composition of their groundwater resource.

“Several SCU student volunteers came on board as part of our research team and gained valuable training on how to sample and analyse groundwater and air samples. They will be part of the future workforce as they can now operate cutting-edge instruments that are quickly becoming standard techniques everywhere,” said Professor Santos.

The research was funded through a collaborative grant between Southern Cross University and the Northern Rivers Regional Organisation of Councils (NOROC).

Photo: PhD candidate Marnie Atkins (right) testing groundwater bores near Casino in September 2013 with environmental science (Honours) graduate Ben Stewart.