Front Range groundwater likely contains hormone-disrupting chemicals due to oil and gas activity

One of many gas wells along the front range
Joel Dyer


A recent study shows evidence of hormone-disrupting chemicals in water near hydraulic fracturing sites in western Colorado, bringing into question the safety of water in Boulder’s heavily drilled backyard of Weld County.

At certain doses, so-called endocrine-disrupting chemicals can interfere with the human hormone system, causing cancer, a number of developmental disorders and birth defects. In a press release, Susan Nagel, an associate professor at the University of Missouri School of Medicine and lead author of the study, said more than 700 chemicals are used in the fracking process, and many of them disrupt hormone function.

With nearly 21,000 active oil and gas wells, Weld County boasts nearly half of the state’s total number of wells. According to the Colorado Oil and Gas Conservation Commission spill database, there were a total of 559 spills in the state in 2013, with more than 307 of those occurring in Weld County.

While the Missouri team didn’t sample water from Weld County, Nagel says there’s cause for concern.

“We bank, based on the statistics that since [spills] are common, that it is highly relevant to Weld County — that where you have spills you will have increased endocrine disrupting activity in water,” she says.

Weld County spokeswoman Jennifer Finch said that she had not heard of the study, but intended to pass the publication on to the five county commissioners for review and comment.

Christopher Kassotis, a doctoral student in Nagel’s lab and co-author of the study, said that of the hundreds of chemicals found in fracking fluid, approximately 150 chemicals are suspected endocrine disruptors.

Prior to taking water samples, the Missouri team performed tests on 12 suspected or known endocrine-disrupting chemicals found in fracking fluid and measured the chemicals’ ability to mimic or block the effects of the reproductive sex hormones estrogen and androgen. Results showed that 11 chemicals blocked estrogen, 10 blocked androgen and one mimicked estrogen.

“We suspect that there are considerably more out there that act as [endocrine-disrupting chemicals],” Kassotis says. He added that the team has continued to test chemicals, confirming a total of 24 compounds found in fracking fluid react with specific hormone interceptors.

Ground- and surface-water samples for the study were taken from accident sites in Garfield County where hydraulic fracturing fluid had been spilled, and also from nearby portions of the Colorado River, which is the main drainage source for the region. As controls, water was sampled from other parts of Garfield County with little drilling activity, and from Boone County, Mo., where there is no natural gas drilling.

“We found more endocrine-disrupting activity in the water close to drilling locations that had experienced spills than at control sites,” Nagel said in the press release. “This could raise the risk of reproductive, metabolic, neurological and other diseases, especially in children who are exposed to endocrine-disrupting chemicals.”

Adding to the damning data from the Missouri study, a team at the Colorado School of Public Health published a study in late January that linked fracking to an increase in birth defects for children born near heavily drilled cities and towns in rural Colorado (See “Born to bad odds,” Boulder Weekly, Feb. 6).

The study used more than 124,000 birth records from the Colorado Department of Public Health and Environment (CDPHE) from 1996 to 2009. The conclusion was “a positive association between greater density and proximity of natural gas wells within a 10-mile radius of maternal residence and greater prevalence of [congenital heart defects].”

The study has come under fire by state public health officials who say that the researchers ignored important factors outside of natural gas development and made questionable interpretations with the data.

When asked about what the study meant in relation to the Missouri study, Kassotis says that other researchers have linked specific endocrine-disrupting chemicals to birth defects in laboratory animals. However, he knows of no studies that have assessed whether the 12 confirmed chemicals from their study are capable of causing birth defects.

Nagel said that while the study, which was produced by the Colorado School of Public Health, didn’t find a correlation between preterm birth, low birth weight and miscarriage, research has shown a positive correlation between those occurrences and exposure to endocrine-disrupting chemicals.

Nagel said her team’s follow-up study would focus on locations that haven’t experienced large spills and determining if there are there other routes of contamination.

“There is the acute exposure that we tend to think of when we think of a spill, but something that we’re also very interested in is the chronic, long-term exposure of folks that live in these areas,” Nagel says. “I think a little bit of that work is being done, but we desperately need more research on the long-term health outcomes of living in these areas.”