Fracking Chemicals May Disrupt Hormonal Activity

Marlene Busko

December 23, 2013

Twelve chemicals used in hydraulic fracturing, or "fracking," operations to extract natural gas all showed endocrine-disrupting chemical (EDC) activity in laboratory cell studies, researchers report.

Moreover, surface and groundwater samples from sites near spills at controversial drilling operations contained higher levels of the 12 EDCs than samples from control sites.

"While these chemicals were selected because of their suspected or known EDC activity, very few had been shown to have direct receptor activity," the researchers write."Thus, this is the first demonstration of antiestrogenic or antiandrogenic activity for most of these chemicals."

The surface and groundwater samples from "sites that have experienced some kind of spill related to natural gas drilling had on average about 2 times the endocrine-disrupting activity than [samples from] sites that had not experienced a spill," senior author Susan C. Nagel, PhD, University of Missouri School of Medicine, Columbia, told Medscape Medical News.

"There is no way at this time to quantify the [potential] effect [on health] other than to say that this is a highly used process in some areas, such as Colorado, where there are up to 50,000 natural gas wells — 10,000 in Garfield County alone," where the water samples were taken, she explained. Spills are common. "There have been 500 spills this year alone in Garfield the potential for exposure is very great."

"Our data suggest that natural-gas drilling operations may result in elevated EDC activity in surface and groundwater," the study, published online December 16 in Endocrinology, concludes.

Focus on 12 Chemicals Used in Fracking


In hydraulic fracturing, several million gallons of water combined with chemicals and solids are pumped into wells under high pressure to fracture shale rock to release natural gas or oil, Nagel and colleagues explain.

"The use of this process has dramatically increased over the past 20 years," and the number of natural gas wells in Colorado has increased almost 10-fold, Dr. Nagel said. Importantly, in 2005, hydraulic fracturing was exempted from multiple federal-regulatory acts including the Safe Drinking Water Act, Clean Water Act, and Clean Air Act.

Reports suggest that more than 750 chemicals are being used for hydraulic fracturing, including over 100 known or suspected EDCs. Exposure to estrogenic chemicals has been linked to decreased fertility and increased cancer incidence, and exposure to antiandrogenic chemicals has been tied to decreased sperm quality and quantity, according to Nagel and colleagues.

They hypothesized that 12 chemicals commonly used in natural-gas drilling operations in Colorado would exhibit estrogen- and androgen-receptor activities. They further hypothesized that surface and groundwater samples collected from 5 sites in Garfield County, Colorado, near hydraulic fracturing operations with reported spills would have greater hormonal-receptor activities than samples from control sites with no or sparse drilling in Boone County, Missouri and Garfield.

Hormonal activity was measured using a gene assay in human cell lines.

Of the 12 chemicals analyzed, 1 (bisphenol A) exhibited estrogenic activity, 11 had antiestrogenic activity, 10 had antiandrogenic activity, and none had androgenic activity. To the researchers' knowledge, this is the first report of antiestrogenic activity of 10 chemicals, including 3 types of ethylene glycol, as well as novel antiandrogenic activity in 6 chemicals, including naphthalene.

In the second part of the analysis, of 39 unique water samples, 89% exhibited estrogenic activity, 41% exhibited antiestrogenic activity, 12% exhibited androgenic activity, and 46% exhibited antiandrogenic activity.

Moderate to high estrogen- or androgen-receptor activities were measured in water samples from the Garfield County spill sites. Moderate-activity levels were also measured in samples collected from the Colorado River, the drainage basin for the region. In contrast, very little receptor activity was measured in water samples where there was no or sparse drilling.

"We identified EDC activity of several individual chemical components used in natural-gas operations that may contribute to the activity that we measured in water," the researchers summarize. They call for more impact studies: "There is evidence that hydraulic fracturing fluids are associated with negative health outcomes, and there is a critical need to quickly and thoroughly evaluate the overall human and environmental health impact of this process."

The study was supported by a grant from the Passport Foundation Science Innovation Fund, and the University of Missouri and STAR Fellowship Assistance Agreement awarded by the United States Environmental Protection Agency.

Endocrinology. Published online December 16, 2013. Abstract


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