Harms unknown: health uncertainties cast doubt on the role of unconventional gas in Australia's energy future

To the Editor: Coram and colleagues' article makes a valuable contribution to understanding the health impacts of unconventional gas mining, highlighting the uncertainties and invoking the precautionary principle.1 In the absence of sufficient well designed epidemiological studies, information is nevertheless accumulating about its impacts on environmental determinants of health, particularly clean air and water.

Despite the incidence of spills, leaks and accidents, the industry has consistently downplayed the risk of aquifer contamination. Yet, in the United States, the US Environmental Protection Agency has documented detection of chemicals “consistent with gas production and hydraulic fracturing fluids” in an aquifer supplying a Wyoming gas-field community.2 Affected well owners were advised to use alternative sources of water for drinking and cooking and adequate ventilation when showering.

More recently, there has been documented contamination of an aquifer in New South Wales by a coal seam gas (CSG) operation, confirmed by the NSW Environment Protection Authority.3 Levels of heavy metals and uranium were found to be elevated in groundwater adjacent to a pond holding produced water (a by-product of gas mining). It is thought that saline produced water leaked out of the pond, mobilising elements from the soil into the groundwater. Numerous leaks or spills of produced water previously occurred at the same operation under a different operator.4 In this instance, there was no direct threat to potable water, livestock or crops. However the current operator is involved in a project elsewhere to use treated CSG water to irrigate crops for cattle fodder, and a trial in Queensland to reinject treated CSG water into Roma's drinking water aquifer.4

High-salinity CSG water can have significant impacts on waterways and soils.4,5 We cannot yet be certain that all contaminants will be removed by current treatment processes.4,5 CSG water may be used treated, untreated or blended with fresh water for watering livestock or fodder.4 Meat and Livestock Australia warns landowners about the potential for contamination of soil, pasture, groundwater and “livestock which, if then processed and consumed, could cause illness”.6 Thus, impacts on water and food security are real concerns. Australian doctors have been raising these and other health concerns about the risks of unconventional gas for some time.7-9