• RETRACTION: The paper described in this article has since been retracted (Environ. Sci. Technol. 2016, DOI: 10.1021/acs.est.6b02342).
    To read C&EN’s coverage of this retraction, click here.
Latest News
Web Date: April 8, 2015

Fracking Activities Pollute Nearby Air With Carcinogenic Hydrocarbons

Environmental Health: Air in the backyards of residents near Ohio fracking sites contains polycyclic aromatic hydrocarbons at levels that could pose increased cancer risk
Department: Science & Technology
News Channels: Environmental SCENE, Analytical SCENE
Keywords: hydraulic fracturing, fracking, natural gas extraction, polycyclic aromatic hydrocarbons, PAHs, carcinogens, air pollution, air quality, monitoring
Citizen Science
A passive air sampler attached to a tree (left) measures airborne polycyclic aromatic hydrocarbons in the backyard of a volunteer living close to a fracking site (right) in Carroll County, Ohio.
Credit: Blair Paulik
Photo of a passive air sampler at a hydraulic fracturing site in Carroll County, Ohio.
Citizen Science
A passive air sampler attached to a tree (left) measures airborne polycyclic aromatic hydrocarbons in the backyard of a volunteer living close to a fracking site (right) in Carroll County, Ohio.
Credit: Blair Paulik

Hydraulic fracturing activities to extract natural gas can release carcinogenic polycyclic aromatic hydrocarbons (PAHs) into the air, a new study shows (Environ. Sci. Technol. 2015, DOI: 10.1021/es506095e). In some cases, the estimated exposure of nearby residents to these compounds exceeded the Environmental Protection Agency’s maximum acceptable risk level for cancer.

Many researchers and community leaders are concerned about the human health impacts of air and water pollution from hydraulic fracturing, often called fracking, and the limited environmental regulation of the industry in the U.S. Fracking can release carcinogens such as benzene into the air along with other volatile organic compounds that are precursors of smog, which can contribute to asthma and other respiratory illnesses (Sci. Total Environ. 2012, DOI: 10.1016/j.scitotenv.2012.02.018).

But few studies have examined the impact of fracking on airborne PAHs, larger molecules that are also linked with cancer and respiratory illness (Atmos. Environ. 2008, DOI: 10.1016/j.atmosenv.2007.12.010). The compounds are present in fossil fuels and are also products of their combustion—for example, they’re found in the exhaust of truck traffic near fracking sites.

Kim A. Anderson, a researcher at Oregon State University, wanted to understand how these compounds might affect workers and residents near fracking operations. So she and her colleagues designed a citizen-science study in Carroll County, Ohio, a community with especially high fracking activity. As of June 2014, the county had 421 natural gas drilling leases, a density of more than one well per square mile. Many community members were concerned about their health impacts, Anderson says.

In February 2014, Anderson and colleagues installed passive air samplers on the properties of 23 volunteers living within 3 miles of active wellheads in the county. The samplers included low-density polyethylene strips to absorb the volatile compounds in air that a person would breathe in. After three weeks, the participants sent the samplers back to the lab in air-tight bags. The team analyzed the collected compounds for 62 PAHs using gas chromatography with tandem mass spectrometry. The researchers then calculated average total concentrations of a set of 14 PAHs for three groups of volunteers on the basis of how far they live from an active well: within 0.1 mile, between 0.1 and 1 mile away, and between 1 and 3 miles away.

For all three groups, the average total PAH concentrations were higher than those measured by a previous study in downtown Chicago and about 10 times greater than those measured in rural areas without fracking activity. The concentrations were 57% higher for the group that lived closest to a well than for the group that lived farthest away.

The researchers also examined the ratios of individual PAHs to determine whether they came from natural gas extraction or car exhaust. At sites closer to the wells, the main source of PAHs was the natural gas itself, whereas sites farther away showed a mixture of exhaust and natural gas signatures.

The researchers then estimated excess lifetime cancer risk for various levels of exposure to all the PAHs they measured using a standard EPA method. For maximum residential exposure of 350 days per year over 26 years, the calculated risk at every distance exceeded EPA’s acceptable range. In all the scenarios they considered, the excess risk for the group closest to wells was about 45% greater than that for the group farthest from them.

David O. Carpenter, an environmental health scientist and physician at the University at Albany, SUNY, says the study provides important new data on PAHs near fracking sites and supports the growing evidence that the process poses added health concerns to people living around the sites. He was surprised by the finding that PAHs are coming mainly from the natural gas itself, because earlier studies of the compounds near fracking sites assumed that vehicle exhaust was the main source. “It opens up a whole new area of research,” he says.

RETRACTION: The paper described in this article has since been retracted (Environ. Sci. Technol. 2016, DOI: 10.1021/acs.est.6b02342).

To read C&EN’s coverage of this retraction, click here.

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John Campbell (Wed Apr 08 14:41:07 EDT 2015)
This is interesting but with 7 or 8 homes in each group it hardly statistically useful. I am staggered though that fracking with an active wellhead was allowed within 176 yards of someone's home.
Mark (Fri Apr 10 10:16:02 EDT 2015)
And yet the average lifespan of people in the area keeps rising. Quite a conundrum.
Court Sandau (Wed Apr 15 14:19:14 EDT 2015)
The first line of the paper is actually not correct. The first line of the paper states: 'Natural gas extraction, often referred to as “fracking" has increased rapidly in the U.S. in recent years.'. Fracking is not the same as natural gas extraction. Fracking is a process to help with natural gas extraction. It is a process that usually happens initially when the well is drilled and takes days to complete. Natural gas extraction would be the all the time the well is in production which can be years of production.

The first line of the paper causes some readers to incorrectly associate the buzz word 'fracking' with PAHs. This paper does not prove that fracking causes PAHs. The production of natural gas and oil causes increases in PAHs in surrounding areas. It is the production process, the on site activities and fugitive emissions that cause the increase in PAHs in and around oil and gas production wells. Fracking may lead to a short term surge of PAHs due to the diesel emissions from the equipment used during the frack or from incineration processes during the frack but this article, as the data has presented doesn't conclusively show that the fracking process caused the increase in PAHs for this study.
Tom Willingham (Sun Jun 26 17:37:43 EDT 2016)
The experimental design is sound. The location of the sampling stations incorporated spatial and temporal factors affecting the results. Both intrinsic and extrinsic factors which could have influenced the results were adequately addressed.

Hydraulic fracturing is an integral predicate to the extraction of hydrocarbons, including PAHs, in situ.

A more thorough, less biased, read of the paper might allow you to better understand the conclusions.
Charles H Bucknam  (Mon Oct 19 18:51:13 EDT 2015)
I think there is a link between fracking and PAHs,fracking releases PAHs from the shale and PAHs could be fracking reagents.
Mark Richardson (Mon Oct 19 19:22:25 EDT 2015)
Actually, US life expectancy is falling for both men and women based on annual income. Income groups below upper middle class have seen life expectancy fall off, more heavily for men than for women. I doubt that living near oil & gas wells either being drilled, fracked, in-production, or abandoned does any good for anyone based on high levels of benzene, methane, VOC emissions, or now these new emissions does anyone any good either, especially not O & G workers, who lately are being injured and dying on the job at record rates too.
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