DENVER, Colo. — Fracking is a procedure used to extract oil or gas from deep underground. The process uses lots of water and lots of chemicals. This means it also produces lots of watery wastes. A series of new tests now show those wastes may be toxic.
Scientists found the wastewater can contain chemicals that alter the action of the body’s hormones. In mice exposed in the womb, the heart and reproductive tissues did not develop normally. Researchers described their new findings here on March 23 at the national meeting of the American Chemical Society.
Many energy companies around the world use hydraulic fracturing — or fracking — to release oil, and especially gas. (That gas usually comes from deposits of shale, a type of rock.) But this process has been controversial. Oil and gas companies inject chemicals deep into wells to flush out the gas and oil. Those chemicals can contaminate groundwater, some studies have shown.
For the new study, researchers worked with human cells and mice. First, they looked for signs in cells that the chemicals altered signaling by any of five different hormones. Hormones are natural chemicals produced by the body’s endocrine system. That system produces hormones that tell various tissues when to turn on or off a particular important action.
For instance, hormones help people process food, identify hunger and recognize when it’s time to sleep. Hormones also tell tissues when it’s time to grow. Puberty and reproduction, for instance, are controlled by a complex series of hormonal changes.
In the new lab tests, the fracking-fluid ingredients each altered the effects of at least one hormone.
Signs of animal impacts
Christopher Kassotis works at the University of Missouri in Columbia. He’s also the study’s lead researcher and an endocrinologist (EN-doh-krin-OLL-uh-gizt), someone who studies hormone impacts. For the new study, his team combined 23 hormone-disrupting chemicals known to have been used by oil and gas companies for fracking.
Hormone-like pollutants can do harm in one of two ways. Some may block a true hormone’s signal. Others may fake out the body, turning on some activity normally triggered by a real hormone.
Energy companies seldom disclose the precise recipe of chemicals in their fracking fluids. But lists of some fracking chemicals have been published. (Such ingredients can include chemicals that kill microbes or that inhibit rust and other forms of corrosion.) Kassotis and his coworkers tried to mix these chemicals in amounts that might roughly match levels in real fracking wastewater.
For their new study, the researchers gave pregnant mice drinking water that contained a cocktail of these fracking chemicals. Male offspring of these mice grew up overweight. Those males also had heavier hearts compared to mice whose mothers hadn’t drunk water containing fracking chemicals. (The researchers are still analyzing the data from female offspring.)
Finally, male mice exposed in the womb to the fracking chemicals developed bigger testes. “This is not actually a good thing,” said Kassotis. Larger testes can lead to cysts and other health problems, he says.
The effects seen in the male offspring echo health problems seen in people: 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.
It’s unlikely people would ever encounter doses of fracking chemicals as high as those given to the mice, Kassotis says. But some human exposures might not be too much lower, he adds. Fracking fluids and wastewaters often spill, he explains. This can taint soils and rivers. In January, for example, a leaking pipeline spewed more than 11 million liters (2.9 million gallons) of fracking wastewater. That pollution entered a stream near Williston, N.D.
Earlier, Kassotis’s team collected samples of soil and water from areas where spills had occurred in Colorado. Hormone-disrupting chemicals showed up.
How dangerous are these exposures to people? No one knows, says Karl Linden. He’s an environmental engineer at the University of Colorado Boulder. But he is developing ways to clean up fracking wastewater. He hopes these techniques will help remove hormone mimicking pollutants.
Scientists don’t know all of the hormone-like chemicals in fracking fluid yet, Linden notes. But, he adds, they’re definitely there.
(for more about Power Words, click here)
cyst A group of cells that form a type of bubble-like shell or sac. Some cysts develop as a result of disease or tissue damage. Others may develop as a normal, protective during certain phases of a parasite’s maturation.
endocrine disruptor A substance that mimics the action (sometimes well, sometimes poorly) of one of the body’s natural hormones. By doing this, the fake hormone can inappropriately turn on, speed up or shut down important cellular processes.
endocrine system The hormones (chemicals secreted by the body) and the tissues in which they turn on (or off) cellular action. Medical doctors who study the role of hormones in health and disease are known as endocrinologists. So are the biologists who study hormone systems in non-human animals.
endocrinologists Doctors who specialize in conditions affecting the production of hormones or the body’s response to hormones.
engineer A person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.
epidemiologist Like health detectives, these researchers figure out what causes a particular illness and how to limit its spread.
hormone (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.
hormone blocker Medications used to suspend the natural development of puberty. Some environmental pollutants may also bind to hormone receptors and block their action. These too may perturb the natural development of a male or female, potentially lending them traits typical of the sex expected based upon their genetic inheritance.
hydraulic fracturing, or fracking The cracking open of undergound rocks by introducing liquid at high pressure, especially to extract natural gas. Those cracks are then held open by sand that had been added to the fracking fluid.
obesity Extremely overweight. Obesity is associated with a wide range of health problems, including type 2 diabetes and high blood pressure. It can perturb healthy hormone signaling. It can even be due to impaired hormone signaling.
pollutant A substance that taints something — such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light. Even weeds and other invasive species can be considered a type of biological pollution.
testis (plural: testes) The organ in the males of many animal species that makes sperm, the reproductive cells that fertilize eggs. This organ also is the primary site that makes testosterone, the primary male sex hormone.
toxic Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.
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R. Ehrenberg. “The facts behind the frack.” Science News. September 8, 2012.
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E. Sohn. “Our plastic world.” Science News for Students. September 26, 2008.
U.S. Environmental Protection Agency website on hydraulic fracturing.
Original Journal Source: C. Kassotis et al. Endocrine disrupting activity of hydraulic fracturing chemicals and health outcomes following prenatal exposure in mice. American Chemical Society National Meeting, Denver, March 23, 2015.
Original Journal Source: C.D. Kassotis et al. Estrogen and androgen receptor activities of hydraulic fracturing chemicals and surface and ground water in a drilling-dense region. Endocrinology. Vol. 155, March 2014, p. 897. doi: 10.1210/en.2013-1697.