The fracking concern with water quality
Gas and hydraulic fracturing, or fracking, in the United States, such as this site in California, raise concerns about possible chemical pollution of surface water and groundwater sources.
PHOTO: DAVID MCNEW/GETTY IMAGES
Unconventional oil and gas development (UOGD) has revolutionized resource extraction over the past two and a half decades. Although these methods to recover oil and gas began in the 1980s, only recently have technological innovations in horizontal drilling and hydraulic fracturing (HF) made it financially feasible to extract resources from difficult-to-access rock formations with low permeability ( 1 ). These innovations have massively increased the availability of oil and gas resources for consumption, yielding energy cost savings, employment, and income ( 2 ). One estimate finds per household benefits to be about 4.9% of income annually ( 3 ). Many have cautioned that human and ecological health may be damaged by the negative environmental impacts that come with these benefits. On page 896 of this issue, Bonetti et al. ( 4 ) report that UOGD has increased salt concentrations in surface waters across the United States. The findings have broad implications for research and policy going forward.
The investigation of four specific UOGD chemicals was motivated in part by best available data. As Bonetti et al. note, however, there may be other chemicals associated with HF that are potentially more dangerous ( 5 ). This highlights the need to expand the set of chemicals measured in the current monitoring system. Moreover, precise measurement of causal effects is dictated by the availability of water monitors, which are spatially sparse. Expanding the geographical scope of water quality surveillance would also improve understanding of the distribution of these effects across regions, different socioeconomic strata, and time. Furthermore, UOGD technology is dynamic. There has been considerable innovation in this industry since UOGD's mass deployment, which has yielded substantial changes in, for example, the lateral and vertical length of oil and gas wells, the number of wellheads per well pad, whether and how water is reused, and the duration of each stage in the life cycle of a well ( 6 ). Notably, these developments affect environmental exposures, and these data are needed to identify the mechanisms of effect. Understanding the exposure pathways at play is necessary for policy to effectively control the environmental damages from these operations.
A looming question also remains regarding whether the water impacts from UOGD translate into health damages or damages on other measures of well-being. Evidence of UOGD water impacts ( 7 ) along with studies of the health impacts of drinking water ( 8 , 9 ) provide indirect evidence that UOGD-related water contamination influences health. Direct evidence is needed. More broadly, continued research in this domain would lend insight into the health benefits of surface water pollution control. A review finds that 67% of US surface water regulations fail a benefit-cost test ( 10 ). That these calculations ignore health benefits is among the hypothesized reasons behind the understatement of net benefits.
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The findings of Bonetti et al. also suggests a need to rethink regulation. Expanding data collection might be achieved by requiring regulatory agencies to collect and report releases of additional chemicals. Because the magnitude of effects reported by Bonetti et al. are below regulatory thresholds that the US Environmental Protection Agency has for drinking water, tightening the stringency of currently regulated chemicals should be considered. Whether it is advantageous to do so depends on whether the associated chemical emissions yield human and ecological health impacts (information that is not yet known). There are also many UOGD chemicals that are unknown to the public. All state regulations allow exemptions for trade secrets to incentivize companies to invest in expensive research and development so that they may recoup the benefits of their investment ( 11 ).
For regulators, these challenges to setting pollution targets may be overcome by requiring firm disclosure of HF chemicals. Enacting any regulation, however, requires consideration of its cost-effectiveness. At 0.8% of gross domestic product in an average year, water-quality regulation is already among the most expensive environmental policies in the United States ( 10 ). Additional regulation may overburden state and local governments. Moreover, firm disclosure of HF fluids may stifle UOGD innovation ( 12 ).
It is not an overstatement to say that UOGD has affected all dimensions of life for those in exposed communities ( 3 ). Many of the impacts have lifelong consequences on individual well-being, including future health, education, and labor market outcomes. The mounting evidence on environmental impacts demonstrates a need to quantify and synthesize the associated health and socioeconomic impacts using a common metric. Benefit-cost analysis is particularly useful to facilitate a comprehensive assessment of the consequences of these innovations ( 13 ). This type of analysis also requires the clarification of alternative scenarios for comparison and the time frame of consideration. For example, would increasing UOGD regulation cause companies to revert to coal-based energy production (thereby exacerbating pollution) or would it instead spur the transition to a renewables-based future to aid the longer-term battle with climate change? The counterfactual scenario of comparison changes the net-benefit calculation and the optimal policy choice.
It has been more than two decades since the rapid expansion of UOGD, but we are only now beginning to grasp the full scope and extent of the costs associated with these innovations. An understanding of the environmental effects of UOGD is a necessary first step toward a comprehensive assessment of UOGD. Going forward, the mechanisms of impact and their consequences must be clarified to translate this evidence into actionable policy.
This is an article distributed under the terms of the Science Journals Default License.
References and Notes
US Geological Survey (USGS), “When did hydraulic fracturing become such a popular approach to oil and gas production?”; www.usgs.gov/faqs/when-did-hydraulic-fracturing-become-such-a-popular-approach-oil-and-gas-production?qt-news_science_products=0#qt-news_science_products.
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Science 20 Aug 2021:
Vol. 373, Issue 6557, pp. 853-854