Fracking chemicals can alter mouse development

DENVER — Wastewater from hydraulic fracturing, or fracking, may tote several hormone-disrupting chemicals that can alter the development of mice, researchers reported March 23 at the national meeting of the American Chemical Society.

Twenty-three chemicals used in fracking fluids can hamper at least one of five hormone signals tested in human cells, the researchers found. When the team gave pregnant mice a cocktail of the chemicals in their drinking water, their male offspring grew up to be overweight and to have heavier hearts compared with mice whose mothers didn’t drink the chemicals. (The researchers are still analyzing the data from female offspring.) Prenatally exposed male mice also had bigger testicles.

“This is not actually a good thing,” said endocrinologist Christopher Kassotis of the University of Missouri in Columbia, the study’s lead researcher. Larger testicles may be linked to cyst development and other health problems, he said. The other effects in mice echo health connections found in humans: Studies have linked other hormone disrupters to obesity. And epidemiologists have found an increased rate of heart defects in babies whose mothers live near natural gas wells, including fracking sites.

Oil and gas companies don’t readily share their recipes for fracking fluid, which is injected deep into wells to flush out shale gas and oil (SN: 9/8/12, p. 20). Hormone-disrupting ingredients can include biocides and corrosion inhibitors.

In lab-made mimics of fracking wastewater, Kassotis and colleagues combined the 23 hormone-disrupting chemicals, which were previously found to be used by oil and gas companies for fracking. The researchers tried to match the chemical concentrations of those chemicals to those of a handful of hormone-disrupting chemicals identified so far in a few samples of real fracking wastewater.

It’s unlikely that people would ever be exposed to doses quite as high, Kassotis said. But the doses might not be far off, he added. Fracking fluids often spill, contaminating ground and surface waters, he explained. In January, for example, a leaking pipeline let loose more than 11 million liters of fracking wastewater into a stream near Williston, N.D.

In a previous study, Kassotis and colleagues collected samples of ground and surface water from areas where spills had occurred in Garfield County, Colo., and found signs of hormone-disrupting chemicals.

The danger of exposure to humans is unknown, said environmental engineer Karl Linden of the University of Colorado Boulder. Linden is developing ways to clean up fracking wastewater, including removing hormone disrupters. He is experimenting with various cleansing processes, such as oxidation reactions. Scientists don’t know the identity of all of the hormone-disrupting chemicals in fracking fluid yet, Linden said. But, he added, they’re definitely there.