Review lists four basic risks involved in hydraulic fracturing that can lead to water contamination

Understanding the risks of hydraulic fracturing to water sources can be a confusing process. A review by scientists at Duke University published last month in the journal Environmental Science & Technology breaks down those risks, making it easier to understand, and providing a helpful took for journalists covering fracking in the current oil and gas boom.

“Most studies so far have found that fracking itself, narrowly defined, does not pose a risk. However, there is evidence that improper drilling techniques, especially faulty surface casing and cementing, can contaminate aquifers," Gayathri Vaidyanathan reports for EnergyWire. "Scientists have found elevated levels of hydrocarbon gases in some groundwater supplies, likely from leaks in well casings, the review states. Gas could also escape through abandoned oil and gas wells or through pre-existing fractures and faults that are adjacent to the formations being fracked.”

The study found four main areas, as described by EnergyWire, that could be a risk:

• Stray methane gas from formations could leak from improperly constructed gas wells into shallow aquifers.
• Wastewater from shale gas drilling could spill at the surface or could be improperly disposed of in streams and rivers.
• Metals or radioactive elements could collect in rivers and streams where partially treated wastewater effluent is released.
• Freshwater withdrawals for fracking could stress groundwater availability in drought-prone regions."

Many areas where fracking occurs have previously been drilled for oil and gas, and lax state regulation could have led to leaks from old wells. (Read more)