Health Impact Assessment of Shale Gas Extraction Workshop Summary (2014) / Chapter Skim
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6 Water Quality
6 Water Quality
Pages 61-82
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From page 61... ...
is discussed as a framework for assessing the impact of hydraulic fracturing on water. Studies to address public concerns regarding water contamination are also described.
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From page 62... ...
. In addition to the fracturing water cycle, it is also important to consider the entire life cycle of water included in the processes of well construction, sand mining, water acquisition, and treatment and disposal during shale gas extraction, Dr.
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From page 63... ...
FIGURE 6-1 Water cycle of hydraulic fracturing.
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From page 64... ...
Reprinted with permission from Shutterstock. It is estimated that between 2 and 4 million gallons of water are used in the lifetime of a shale gas extraction well.
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From page 65... ...
Some localities use wastewater treatment plants to dispose of the water, but it has been said that not all wastewater treatment plants are capable of treating all chemicals found in the wastewater from fracturing. Wastewater treatment plants were not designed to treat for some of those contaminants.
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The current situation is that either they are not on the safe drinking water list or they are not on the list of what is being measured for wastewater treatment. Many of the well sites also use a pit to collect their wastewater.
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From page 67... ...
Not only with wells that are used for shale gas extraction, but in general all wells of similar construction present the most noticeable weaknesses in their physical structure. Most reports on contamination of aquifers pinpoint the cause of contamination as a leak of the well casing, pipes, or storage tanks.
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From page 68... ...
These areas include understanding the fate of the fracturing fluid; toxic burden for exposure analysis; impact of flowback water and produced water; effectiveness of contaminant removal and disposal technologies; cumulative impacts of refracturing; research alternatives to the current hydraulic fracturing practices; effective monitoring strategies to be implemented; fingerprints of chemicals and fracturing fluids; exposure modeling of populations, including vulnerable populat ions; and social impacts and outcomes. There are many knowledge gaps and much research is needed, she said.
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From page 69... ...
Used with permission from Taylor & Francis. TABLE 6-1 Percent of Chemicals in Fracturing Fluids Identified in Colborn et al.
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From page 70... ...
Those waters should be kept from contaminating the surface groundwater where drinking water is obtained. Fracturing fluids used in the hydraulic fracturing process interact with water sources.
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Management of Produced Water Dr. Jackson turned to discuss produced waters which are primarily a combination of naturally occurring deep formation waters and fracturing fluids.
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It is not recommended to dispose of produced waters in municipal wastewater treatment plants, Dr. Jackson said.
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From page 73... ...
This practice reduces the amount of water needed to be acquired and also reduces the expense of wastewater treatment. The challenge of reusing the water is monitoring the concentrations of chemicals in the produced water.
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FIGURE 6-8 No evidence of brines or fracturing fluids was present, but methane concentrations in drinking water were higher near gas wells. The gray band is the Department of the Interior hazard mitigation recommendation.
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Jackson briefly noted the situation in Pavillion, Wyoming. As mentioned earlier, one of the biggest public concerns is organics from fracturing fluids leaking into drinking water.
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76 HEALTH IMPACT ASSESSMENT OF SHALE GAS EXTRACTION In concluding his remarks, Dr. Jackson identified a number of positive developments on the water front: industry-driven initiative to recycle and reuse water for fracturing the next well; greater disclosure of the chemicals in fracturing fluids (except those that are trade secret)
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From page 77... ...
As the technologies evolve, the possibility of acquiring more of the shale gas deposits has become more viable. To clarify many of the concerns from the public and to develop a standardized practice for industry, Congress asked the EPA to study the impact of hydraulic fracturing on drinking water resources.3 Dr.
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From page 78... ...
Laboratory studies can be used to understand the interaction of hydraulic fracturing fluids and shale formations. There are different types of hydraulic fracturing fluids and each of the fluids interacts with the different types of shale formations.
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From page 79... ...
Hydraulic fracturing is only regulated under the Safe Drinking Water Act if diesel fuel is used. When diesel fuel is used, a permit is required through the Underground Injection Control Program.4 As was stated earlier, there is cause for concern if drinking water is contaminated with diesel because of human health effects.
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From page 80... ...
PowerPoint presentation at the Institute of Medicine workshop on the Health Impact Assessment of New Energy Sources: Shale Gas Extraction, Washington, DC. 5 See http://www.epa.gov/hfstudy (accessed May 30, 2013)
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From page 81... ...
PowerPoint presentation at the Institute of Medicine workshop on the Health Impact Assessment of New Energy Sources: Shale Gas Extraction, Washington, DC.
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