Coal seam gas extraction and coal mining may release chemicals into the environment. These chemicals could be toxic to aquatic and terrestrial organisms or affect water quality, which could also adversely impact on human health. The toxicity of chemicals must be evaluated in order to properly understand and manage the risks.
Coal seam gas extraction and coal mining may also inadvertently mobilise naturally occurring underground chemicals and bring them to the surface in co-produced water or mine discharge water.
As well as chemical and ecotoxicological investigations, this theme includes potential cross-contamination of drinking water and other water resources through the interconnection of previously isolated aquifers and surface waters.
Consideration is given to how these issues contribute to the overall cumulative impacts of coal seam gas extraction and coal mining, according to different scales (local-regional) and timeframes (tens to thousands of years).
Projects
Projects commissioned to date include:
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Background Review: Hydraulic Fracturing Techniques
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This review captures the state of knowledge of hydraulic fracturing associated with coal seam gas extraction, including:
- the techniques involved
- risks and how they are managed
- regulatory environment
Background Review:
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National assessment of chemicals associated with coal seam gas extraction in Australia
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The Assessment was led by the Department of the Environment and Energy in collaboration with the National Industrial Chemicals Notification and Assessment Scheme, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), and in an advisory role, Geoscience Australia. It drew on the expertise of scientists in the fields of chemistry, hydrogeology, hydrology, geology, toxicology, eco-toxicology, natural resource management and risk assessment.
The Assessment examined human health and environmental risks from chemicals used in drilling and hydraulic fracturing for CSG in Australia between 2010 and 2012. It aimed to increase the knowledge base about chemicals used in the industry and provide information to the Australian Government, the IESC, industry, and the public about the use and potential risks of these chemicals.
The Assessment:
- helps to develop understanding among stakeholders of the public, occupational and environmental risks arising from chemicals used in drilling and hydraulic fracturing for CSG extraction in Australia
- provides an evidence base for the appropriate management of chemicals as part of the broader management of CSG activities; and
- improves the public access to information about chemicals used in hydraulic fracturing operations.
- developed improved, targeted methods for assessing the risks of chemicals used in coal seam gas operations, and included release of a consultation draft Chemical Risk Assessment Guidance Manual.
Find out more about the Assessment:
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Deeper groundwater hazard screening research
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This work provides information to help characterise risks from chemicals associated with coal seam gas extraction in Australia to deeper groundwater, associated surface and subsurface water sources, and water dependent assets such as bores and aquifers. The project does not assess risks from any individual project or chemical.
The research includes:
- Conceptual models to help screen hazards associated with the chemicals used in coal seam gas extraction and deeper groundwater.
- Spatial analyses of coal seam gas extraction activities, hydraulic fracturing operations, and water dependent assets in selected study areas to help understand how likely chemicals are to move between different bodies of water.
- Improved understanding of chemical, biological and geological processes that affect the movement of chemicals in deeper groundwater.
Report and Appendices: