An overview of possible
impacts from coal seam gas development in
Northern Rivers, New South Wales
Integrated Project by Elfian
4.3 Contamination of Groundwater
Major threats to ground water quality are from salinity,
acidity, nutrients and contaminants such as heavy metals, industrial chemicals
Contamination of ground water can have significant economic
impacts through decreasing agricultural and horticultural productivity, causing
environmental damage in ground water dependent ecosystems and pose serious risks
to human and animal health (Geoscience Australia, 2011).
Opportunities for contamination from CSG occur via
interconnectivity between aquifers and gas wells, disposal of produced water and
leakages (NTN, 2011).
Problems such as borehole fractures and compression failures
(Asquith and Krygowski, 2004) may allow the transmission of fluids and gases
into permeable rock layers adjacent to gas wells.
Reports from the United States indicate that leakage from
holding ponds and wells has occurred into nearby streams and in some cases risen
to the surface in fields via aquifers (Bamberger and Oswald, 2012).
In Tara, QLD spraying produced water onto roads as a dust
suppressant is considered a viable option for disposal (Arrow Energy Pty Ltd,
Contaminants entering the environment through these channels
can be transported elsewhere via wind and water posing health risks to animals
and humans (see section 5.2 for details).
Queensland residents report of methane leaking into the
Condamine River in Western Downs region (Wroe, 2012).
Another Queensland resident reports that his domestic bore
experienced explosions and can catch fire if naked flame is held to it
Arrow Energy’s Environmental Impact Statement (2012) states
that the Condamine Aquifer overlies the Walloon Coal measures in several places
and that there is possible connectivity between the two.
According to the Queensland Government and Origin Energy, the
methane leaking through the river is naturally occurring due to a shallow coal
seam under the surface.
Origin Energy made clear it was their understanding the
leakage was natural because they had no production wells nearby, however, they
were unable to be absolutely certain and made no mention of possible locations
of exploration wells (Rego, 2012).
Research in America discovered that methane concentrations
have occurred in high to explosive levels (above 7-10mg/L) near to gas
Levels of 19.2 and 64 mg/L of methane were recorded from bore
wells in gas extraction areas in Pennsylvania and New York (Osborn et al, 2011).
An assessment of 58 gas wells in Tara in QLD identified 26
leaking wells, 5 of which were leaking above the lower explosive limits for
methane (Australian Department of Employment, Economic Development and
A NSW inquiry into coal seam gas concludes that the potential
impacts to water resources could be disastrous and that urgent scientific
research is needed to assess the potential for these impacts to occur (NSW
Queensland | Western Australia |
South Australia |