State to assess human health risks of fracking
The results of a three-year Colorado State University study on air emissions from natural gas extraction will fuel a state assessment of the human health risks posed by fracking.
A team of CSU researchers carried out the $1.7 million study in Garfield County in northwest Colorado, a major hub for oil and gas activity.
The team's goal was to collect and quantify emissions of volatile organic compounds, a major player in smog development, and methane, a potent greenhouse gas that traps more heat than carbon dioxide. As explained in a CSU press release, they examined emissions from three natural gas extraction activities: drilling, fracking and flowback.
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Fracking is the controversial practice of sending high-pressure water, sand and chemicals into underground formations to extract oil and gas. Flowback refers to the last step of completing the well, when groundwater and fracking fluids flow to the surface after injecting water and chemicals into the well.
"We wanted to look at drilling, fracking and flowback, because emissions from these activities have received little prior study, especially for VOCs," said study leader Jeffrey Collett, professor and head of CSU's Department of Atmospheric Science, in a CSU press release.
The study was unique not only because of its length but also because it received full cooperation — and funding — from Garfield County and oil and gas operators.
Some notable takeaways from the study included:
- The team saw higher emission rates of methane and many volatile organic compounds — they tracked 48 — during flowback than during drilling or fracking.
- Methane was the most abundant in emissions of all the compounds tracked. Methane emissions during flowback were 20 times the rate during drilling and 13 times the rate during fracking.
- Among the VOCs tracked, the researchers noted wide ranges of emission rates both across and within the three activities.
The Colorado Department of Public Health and Environment will put the team's air emissions data to use in an upcoming health assessment.
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"This evaluation will improve our understanding of the potential for health risks directly attributable to air emissions from oil and gas," said Mike Van Dyke, the department's branch chief of environmental epidemiology, occupational health and toxicology, in the release.
The CSU field team conducted 21 experiments at various operating sites in Garfield County, using a "tracer ratio method" to figure out emission rates. They used acetylene as the tracer gas, releasing it downwind of well pads via "mobile plume trackers" — hybrid SUVs equipped with specialized instruments.
And they employed a host of other complex research tactics, including taking constant meteorological measurements to predict where emissions would travel.
Full findings will be available from CSU by July 1, and the team is preparing peer-reviewed journal articles about the study. They're also working on a similar study of oil and gas emissions along the northern Front Range.