by Alex Frumkin
There has been a rapid increase in shale gas development in the united States due to the increase in use of hydraulic fracturing to access these shale beds. The rise of hydraulic fracturing has lead to intense public debates about the potential environmental and human health effects from hydraulic fracturing. Vengosh at el. (2014) identifies four potential areas of risks for water resources from hydraulic fracturing: contamination of shallow aquifers due to stray gas contamination, contamination of surface water and shallow groundwater from spills, leaks, and/or the disposal of inadequately treated shale gas wastewater, accumulation of toxic and radioactive elements in soil near disposal or spill sides, and the over extraction of water resources that could induce water shortages. To be able to fully understand the water contamination risks associated with hydraulic fracturing there needs to be an in depth investigation of the hydrology, hydrogeology, water chemistry, and isotopic tracers for identifying what the cause of the water contamination is.
The review of the literature identified four possible risks to water resources. Hydraulic fracturing could lead to stray gas leaking into shallow aquifers due to poorly constructed or failing gas wells. This process could happen over a long time so any current evidence of stray gas contamination could be a clue for future water degradation. Water resources could also be contaminated in areas where hydraulic fracturing is occurring because of spills, leaks, or disposal of hydraulic fracturing fluids and/or inadequately treated wastewater. Both of these are full of chemicals that can be highly damaging for both human and environmental health. There’s also the possibility of metal and radioactive element accumulation in water-ways due to disposal or spill sites. This is problematic because this accumulation can release toxic elements and radiation into the environment. The last identified risk is the overexploitation of limited or diminished water resources due to huge withdrawals of valuable fresh water that is necessary for hydraulic fracturing to be done.
There is still debate around whether hydraulic fracturing does pose these risks to water resources, and if the risks are there, how severe the risks really are. In order to put an end to this debate, it’s necessary to develop a data for baseline water chemistry in aquifers before hydraulic fracturing begins. It is imperative that a comprehensive investigation is completed on the hydrology, hydrogeology, water chemistry, and isotopic tracers to identify whether water contamination has occurred near hydraulic fracturing sites. In order to fully put a rest to this debate, these investigations need to happen at shale gas developments across the country, not just at a few geographic locations.
Vengosh, Avner. Jackson, Robert. Warner, Nathaniel. 2014. A Critical Review of the Risks to Water Resources from Unconventional Shale Gas Development and Hydraulic Fracturing in the United States. doi.org/10.101021/es405118y