Endocrine (Hormone) Disruptors

There is mounting concern in the scientific, environmental, private, and governmental sectors on a wide range of substances, known as endocrine disruptors, that may interfere with the normal functioning of a living organism's hormone system. Endocrine disruption has the potential to cause:

  • reproductive
  • behavioral
  • immune system, and
  • neurological problems, and
  • tumors.

Research shows that endocrine disruptors may pose the greatest risk to offspring during prenatal and early postnatal development when organ and neural systems are developing. However, adverse consequences may not be apparent until much later in life.(1) In addition, endocrine disruptors may affect not just the offspring of mothers exposed to endocrine disruptors during pregnancy, but future offspring as well.(2)

    Chemicals that mimic or antagonize the:
  • female estrogenic hormones,
  • male androgenic hormones (such as testosterone), or
  • thyroid hormones,

are currently receiving the most attention. All three groups are needed to support life in mammals, including people, as well as amphibians, fish, birds, and reptiles. Possible effects on invertebrates also are receiving attention.

DDT (Dichloro-Diphenyl-Trichloroethane) is probably the most notorious pesticide ever. DDT and its breakdown product DDE, like other organochlorines, have been shown to have xenoestrogenic activity; meaning they are chemically similar enough to estrogens to trigger hormonal responses in animals. More about DDT.

In order to manage fish and wildlife populations for the American people, the Fish and Wildlife Service addresses the risks and effects of organic pollutants, metals and pesticides, including those that may possess endocrine activity, on the natural resources of the country.


DEQ News and Activities. November 29, 2006. Assessing Endocrine Disruption in Bass in the Potomac River Watershed. (includes links to KARE 11 Minneapolis/Saint Paul video clip on intersex fish in the Mississippi River and The Washington Post article - "Male Bass across Region found to be Bearing Eggs".)

U.S. Geological Survey: Oversight Hearing on "Ova-Pollution in the Potomac:  Egg-Bearing Male Bass and Implications for Human and Ecological Health". Statement of Mark Myers, Director U.S. Geological Survey, Department of the Interior Before the House Committee on Government Reform. October 4, 2006

Center for Bioenvironmental Research of Tulane and Xavier Universities New Orleans, Louisiana: E.Hormones...Your Gateway to the Environment and Hormones...

National Academy of Science Report: Read and Order Information- Hormonally Active Agents in the Environment - July 1999

Organization for Economic Co-operation and Development (OECD) - Endocrine Disrupter Testing and Assessment

Society of Environmental Toxicology and Chemistry - Books on Endocrine Disruption

U.S. Geological Survey National Water Quality Assessment Program - Pesticide National Synthesis Project

US Geological Survey. Report on the potential for endocrine disruption in common carp from streams throughout the United States

(1) Environmental Health Perspectives 103:83-87, 1995. Endocrinology 147 (6) Supplement S11-S17, 2006.

(2) Science 3 June 20. Vol. 308. no. 5727, pp. 1466 - 1469.

Last updated: April 17, 2014