Explainer: About Endocrine Disruptors and the Endocrine System

Wisconsin Center for Investigative Journalism

Hormones flip the switches of the endocrine system, which regulates metabolism, reproduction, energy, growth and other body functions.

Scientists have learned that some chemicals — possibly thousands — may mimic or disrupt the hormones of people and wildlife, with potentially health-damaging results. They can be natural, like the estrogens produced by plants or cows, or synthetic, like birth control pills.

They are called endocrine disruptors.

Expert Laurence Shore, a physiologist in Israel[1], ticked off some of their most worrisome potential health effects: Reduced sperm counts. Lower testosterone. Genital birth defects in males. Earlier puberty in kids.

The chemicals are also suspected of causing cancer, according to a United Nations report that called them a “global threat.”

Suspected endocrine disruptors are now known to be widespread in the nation’s surface waters. The Wisconsin Center for Investigative Journalism published an April report showing that while Wisconsin has done little testing, Minnesota found these chemicals in nearly every lake or stream it sampled, even in remote locations.

To a lesser extent, they also are turning up in groundwater, including drinking water.

The science of assessing their risks to people and wildlife is complicated, expensive and often controversial.

The U.S. Environmental Protection Agency is studying the effects of hormones and other endocrine disruptors on the environment, but is not yet far enough along to make policy or regulation changes, according to an email from the agency.

The state Department of Natural Resources’ drinking water program has established health standards for 63 chemicals that are among EPA’s top priorities to study for endocrine disruption potential. The standards are based on evidence that they pose a risk to human health and either have been or are likely to be found in groundwater.

The state’s Groundwater Coordinating Council, an interagency group, has funded limited research on these emerging pollutants, including the University of Wisconsin-Green Bay study led by Angela Bauer that found estrogenic water in private wells.

But to a large extent, the state is waiting for guidance on endocrine disruptors from the EPA, which has been criticized for its slow progress in identifying the greatest risks.

“Our current program is what we believe to be an appropriate balance at this time while further research, technology and EPA guidance is developed,” DNR spokesman Bill Cosh said.

What’s the Endocrine System?

The endocrine system is one of the body’s main systems for communicating, controlling and coordinating the body’s work. It works with the nervous system, reproductive system, kidneys, gut, liver, pancreas and fat to help maintain and control the following:

  • body energy levels
  • reproduction
  • growth and development
  • internal balance of body systems, called homeostasis
  • responses to surroundings, stress and injury

Source: The Hormone Network, the public information arm of the Endocrine Society