Findings confirm health risks to people living near oil and gas wells
FRISCO — Careful air sampling near active natural gas wells in Carroll County, Ohio showed the widespread presence of toxic air pollution at higher levels than the Environmental Protection Agency considers safe for lifetime exposure, according to scientists from Oregon State University and the University of Cincinnati.
The study reinforces the need for more extensive air quality monitoring in fracking zones around the country, where exposure to the poisonous emissions are likely to lead to increased risk of cancer and respiratory ailments.
“Air pollution from fracking operations may pose an under-recognized health hazard to people living near them,” said the study’s coauthor Kim Anderson, an environmental chemist with OSU’s College of Agricultural Sciences.
Anderson and her colleagues collected air samples during a three-week period last February in a highly fracked area, with more than one active well site per square mile. The study was spurred by local residents who wanted to know more about possible health risks.
The air samplers were placed on the properties of 23 volunteers living or working at sites ranging from right next to a gas well to a little more than three miles away. The samples were sent to Anderson’s lab at OSU, where the analysis showed high levels of PAHs across the study area. Levels were highest closest to the wells and decreased by about 30 percent with distance.
Even the lowest levels — detected on sites more than a mile away from a well — were higher than previous researchers had found in downtown Chicago and near a Belgian oil refinery. They were about 10 times higher than in a rural Michigan area with no natural gas wells.
The scientists said they were able to differentiate between pollution coming directly from the earth and from other sources like wood smoke or auto exhausts, supporting the conclusion that the gas wells were contributing to the higher PAH levels.
The researchers then used a standard calculation to determine the additional cancer risk posed by airborne contaminants over a range of scenarios. For the worst-case scenario (exposure 24 hours a day over 25 years), they found that a person anywhere in the study area would be exposed at a risk level exceeding the threshold of what the EPA deems acceptable.
The highest-risk areas were those nearest the wells, Anderson said. Areas more than a mile away posed about 30 percent less risk.
Anderson cautioned that these numbers are worst-case estimates and can’t predict the risk to any particular individual.
“Actual risk would depend heavily on exposure time, exposure frequency and proximity to a natural gas well,” she said.
“We made these calculations to put our findings in context with other, similar risk assessments and to compare the levels we found with the EPA’s acceptable risk level.”
The study has other caveats, Anderson said, the main one being the small number of non-random samples used. In addition, findings aren’t necessarily applicable to other gas-producing areas, because PAH emissions are influenced by extraction techniques and by underlying geology.
The study, which appears in the journal Environmental Science & Technology‘s online edition, is part of a larger project co-led by the University of Cincinnati’s Erin Haynes, OSU’s Anderson, her graduate student Blair Paulik and Laurel Kincl, director of OSU’s Environmental Health Science Center.