Several years into the modern "fracking" era in the United States (US), there still isn't enough rigorous research to determine whether or how the practice may threaten human health, according to a recent commentary.
Investigators have begun trying to tease out the long-term effects of this natural gas extraction technology, but answers on whether people who live near fracking sites are at increased risk of disease are likely several more years away, given the complexity of this research - and the fact that many people who have allowed companies to lease their land for fracking have signed confidentiality agreements, says the lead author.
"For the most part, they're not allowed to talk about any ill effects to themselves, to their water, to their land, even to their animals," Madelon Finkel, an epidemiologist at Weill Cornell Medical College in New York City, told Reuters Health in an interview. "That in a sense is hampering the ability to do good research."
Finkel and her colleague Jake Hays of PSE Healthy Energy in New York City co-authored a call for high quality epidemiological research on the environmental and health impacts of fracking in the Journal of Epidemiology and Community Health.
"The available science raises substantial questions about the potential for harm to health," they write. And people living near drilling sites "are presenting with symptoms (e.g., skin rashes, nausea, abdominal pain, respiratory difficulties, headaches, dizziness, eye irritations, throat irritations, nosebleeds, anxiety and stress) that demand further investigation."
High-volume hydraulic fracturing involves pumping millions of gallons of water, chemicals and sand or silica at high pressure into holes drilled into rock formations. This causes small fractures in the rock that allow natural gas or oil to escape. The fluid that flows back after fracking contains "thousands of gallons of toxic chemicals, the vast majority of which are not identified," Finkel and Hays write in their commentary.
"Wells have blowouts, spills are common, and methane is leaked and vented into the atmosphere at all stages of the extraction process," they add. Finkel is combing through Pennsylvania Department of Health data from the heavily fracked southwest portion of the state to investigate whether there is any association between fracking and cancers that are known to be linked to environmental contamination, such as bladder cancer, thyroid cancer and leukemia.
She has identified higher-than-expected rates of cancer in Washington County post-fracking, but she also learned that cancer rates had been high before fracking was introduced to the region. "As I dug deeper, I realised that in a lot of these communities and counties there was a lot of coal mining going on in that area, and there were a lot of chemical industries that were in operation there," she said. For example, uranium tailings had been dumped in one site - and a golf course built on top of the dump.
In addition to sorting out these environmental factors, investigators must look at lifestyle factors such as smoking, alcohol use and diet among people living in the area, Finkel added. She hopes to perform a case-control study to hone in on the potential health effects of fracking. This involves matching people with an illness to similar individuals who are free from the illness, and figuring out whether the two groups have different "exposures."
For example, Finkel said, it's possible to measure the distance between a person's home and the closest fracking fluid well, to see if people who live closer to these wells are at greater risk of disease.
"Until we do that, what we have is 'he says, she says,'" Finkel said. "We just have to be careful not to airbrush things and say, 'well, you're sick because of the fracking."
For now, she added, "safeguards should be put in place to minimise the potential for harm." This would involve, for example, storing, treating and disposing of fracking fluid carefully to avoid contaminating drinking water supplies, and taking steps to capture methane.
"I'm not anti-fracking per se," Finkel said. "I'm just saying, do it cleanly and appropriately and correctly."
