Buried just below the surface of wide stretches of the Midwest lies a natural resource that has only recently skyrocketed in value: silica sand. In the past decade it has played a major role in hydraulic fracturing or “fracking,” a drilling process that has helped the United States hit what many observers consider to be a domestic natural gas jackpot.
While fracking has ignited controversy because of its potential to taint water supplies near gas and oil wells, the environmental impact of extracting silica sand is not well understood. With mining companies poised to launch operations in northeast Iowa, concerned citizens there have called upon University of Iowa researchers to investigate.
Since about 2005, fracking has flourished in the United States. Energy companies using the technique have unlocked vast stores of natural gas and oil previously believed to be unreachable because they were embedded in shale rock and limestone. Fracking, a high-pressure application of water, chemicals, and silica sand (also known as “frac sand”), creates fissures in the rock, releasing the trapped gas and oil. The frac sand is essential because it infiltrates the cracks and keeps them propped open. One well can require hundreds or even thousands of tons of frac sand.
Constantly hungry for more of the sand, the burgeoning fracking industry has quickly spawned extensive sand mining outposts in Wisconsin, Minnesota, and Illinois. But when mining companies set their sights on deposits in Allamakee and Winneshiek counties in northeast Iowa, residents formed citizen-action groups and got in touch with David Osterberg, a member of the outreach team of the Environmental Health Sciences Research Center (EHSRC) based in the College of Public Health.
“Frankly, they’re very worried,” says Osterberg, clinical professor of occupational and environmental health. He says a key concern is crystalline silica.
Crystalline Silica and Silicosis
A fine dust that is the byproduct of the mining process, respirable crystalline silica is known to cause silicosis, an incurable scarring of tissue in the lungs that can lead to severe shortness of breath and, eventually, death. Silica exposure has also been linked to other diseases, such as emphysema, tuberculosis, lung cancer, and some immune-system ailments.
The U.S. Occupational Safety and Health Administration describes occupational exposure to crystalline silica as “a serious threat” to some 2 million American workers in mining and other industries. But very little is known about the impact of ambient exposure to the dust; that is, exposure to residents of communities surrounding the mining operations. To date, no conclusive evidence has been found that demonstrates that sand mining leads to silicosis in people living in surrounding communities. But silicosis has been identified in farm animals living downwind of sources of crystalline silica.
The citizens’ groups convinced the supervisors of Allamakee and Winneshiek counties to impose 18-month moratoria on frac sand mining until they’ve had a chance to consider development of local mining regulations and to assess the impact of mining on the region, which has an economy that depends heavily on tourism and second-home construction.
Study Sparks New Inventions
After establishing contacts with several fledgling efforts to monitor air quality around frac sand operations in Wisconsin, the EHSRC procured a $125,000 grant from the National Institute of Environmental Health Sciences in September 2013 to conduct a year-long air-quality study that will unify those projects and generate new research. Led by Peter Thorne, director of the EHSRC and professor and head of occupational and environmental health, the study funds UI researchers to develop novel methods for sampling and monitoring air around mining operations.
Tom Peters, associate professor of occupational and environmental health, is directing the exposure assessment portion of the research, which includes real-time monitoring of air affected by mining-related activities, development of low-cost detectors for long-term monitoring, and collection of particles through air sampling.
Ryan Grant, a graduate student in biomedical engineering, is working on the real-time monitoring leg, beginning with constructing and deploying a detection device that sits near railroad tracks that service frac sand operations.
“We’re inventing ways to associate airborne particle concentrations with events in the environment,” Peters says. “For example, when a train goes by, the sound from the train triggers a camera to take a picture, so we’re able to get an idea of whether it’s a sand train. Then it monitors the particulate matter levels in the air.”
They will try to identify particles with diameters that range from 2.5 to 10 micrometers and determine if any of the particulate matter includes crystalline silica. Crystalline silica smaller than 4 micrometers is the type most likely to reach the alveoli of the lungs and cause silicosis.
Other components of the study lend support to ongoing work. Patrick O’Shaughnessy, professor of occupational and environmental health, will extend current air-sampling efforts by conducting modeling of air conditions, extrapolating the Wisconsin data, for example, to determine how air-quality levels might change at the as-yet-undeveloped Iowa mine locations.
And Liz Swanton, a master’s student in the Department of Community and Behavioral Health, will develop training videos to teach public health department personnel how to employ standardized air-monitoring methods that will keep communities informed of whether their local mines are complying with standards.
“Mining permits require you to apply dust-suppression techniques to minimize fugitive emissions,” Peters says. “Some people do, some people don’t. There is no monitoring to check.” The low-cost monitors that the team develops will provide a way to check inexpensively. The video training will also ensure a continuing flow of reliable data.
Making It Public
All the data will come together into a risk assessment led by Thorne that will inform the public about the levels of exposure and the risks to public health. These findings will be presented at workshops, where UI researchers will advise stakeholders, including policymakers, mining industry representatives, citizens’ groups, and academic institutions.
Peters, who has worked on projects with national impact, takes pride in how the work he and his colleagues do on this study will have long-term local benefits.
“This is a unique, regional issue,” he says. “It’s the first time I’ve been on a project with this degree of community participation. It’s been fun.”