The Colorado River flows through the town of Rifle in Garfield County, Colorado. Photo (taken 1972) by David Hiser, courtesy of U.S. National Archives, Flickr/Creative Commons.

Original article by Sandra Postel, National Geographic

This week, more evidence came in that hydraulic fracturing (or fracking) poses potentially serious risks to drinking water quality and human health.

A team of researchers from the University of Missouri found evidence of hormone-disrupting activity in water located near fracking sites – including samples taken from the Colorado River near a dense drilling region of western Colorado.

The Colorado River is a source of drinking water for more than 30 million people.

The peer-reviewed study was published this week in the journal Endocrinology.

Fracking is the controversial process of blasting water mixed with sand and chemicals deep underground at high pressure so as to fracture rock and release the oil and gas it holds. It has made previously inaccessible fossil fuel reserves economical to tap, and drilling operations have spread rapidly across the country.

The University of Missouri team found that 11 chemicals commonly used in the fracking process are “endocrine disrupters” – compounds that can affect the human hormonal system and have been linked to cancer, birth defects, and infertility.

“More than 700 chemicals are used in the fracking process, and many of them disturb hormone function,” said Dr. Susan Nagel, associate professor of obstetrics, gynecology, and women’s health at the University of Missouri School of Medicine and a co-author of the study, in a news release.

“With fracking on the rise, populations may face greater health risks from increased endocrine-disrupting chemical exposure.”

The research team collected samples from ground water and surface water from sites in Garfield County, Colorado, where fracking fluids had accidentally spilled, as well as from the nearby Colorado River, into which local streams and groundwater drain. They also took samples from other areas of Garfield County where little drilling has taken place, as well as from a county in Missouri where there had been no drilling at all.

They found that the samples from the spill site had moderate-to-high levels of endocrine-disrupting activity, and the Colorado River samples had moderate levels.  The other two samples, taken from areas with little or no drilling activity, showed low levels of endocrine-disrupting activity.

The new findings add urgency to calls for moratoriums on fracking until the risks have been fully assessed and regulations and monitoring put in place to safeguard water supplies and public health.

Due to the so-called “Halliburton loophole,” the oil and gas industry is exempt from important requirements under the federal Safe Drinking Water Act, and states have been slow to fill the regulatory gap.

Colorado, in particular, should exercise the utmost caution.

According to a report by Ceres, a Boston-based non-profit organization that educates investors about corporate environmental risks, 92 percent of Colorado’s shale gas and oil wells are located in “extremely high” water stress regions, defined as areas in which cities, industries and farms are already using 80 percent or more of available water.

Adding contamination risks to the high volume of water fracking wells require – typically 4-6 million gallons per well – argues strongly for a precautionary approach to future development and a pause in existing production until the full range of environmental health risks can be assessed.

But Colorado Governor John Hickenlooper has said the state will sue any city that bans fracking within its borders.  Indeed, in July 2012, the state sued the front-range town of Longmont, which had issued such a ban.

A statement about the new findings of endocrine-disrupting chemicals (EDCs) in waters near fracking sites issued by Concerned Health Professionals of New York, and posted here, concludes with this warning:

“These results, which are based on validated cell cultures, demonstrate that public health concerns about fracking are well-founded and extend to our hormone systems. The stakes could not be higher. Exposure to EDCs has been variously linked to breast cancer, infertility, birth defects, and learning disabilities. Scientists have identified no safe threshold of exposure for EDCs, especially for pregnant women, infants, and children.”

And environmental health expert Sandra Steingraber writes in a letter posted at the same site:

“[I]t seems to me, the ethical response on the part of the environmental health community is to reissue a call that many have made already:  hit the pause button via a national moratorium on high volume, horizontal drilling and fracking and commence a comprehensive Health Impact Assessment with full public participation.”