Endocrine Disrupting Chemicals: FAQs
On this page:
What are endocrine disrupting chemicals (EDCs)?
What types of chemicals can act as EDCs?
What is the endocrine system?
Why the concern about EDCs?
What is their controversy about EDCs?
What is the scientific community doing about EDCs?
What is Minnesota doing about EDCs?
Where can I obtain more information?
EDCs are chemicals, both synthetic and natural, that alter or affect the endocrine system in animals and humans. Over the last decade there has been increasing global concern that the exposures to low levels of EDCs found in the environment has the potential to interfere with the normal function of the endocrine system in wildlife and humans.
EDCs as a group are diverse, and it is impossible to characterize them on the basis of their chemical structure. However, a number of individual chemicals have been implicated as EDCs, including:
- Dioxins – a byproduct of combustion
- PCBs – now banned, but were widely used as coolants and lubricants in electrical equipment
- Bisphenol A – used to produce polycarbonate plastics, polymers, and resins;
- Phthalate plasticizers such as DEHP, DBP, DINP – used to make plastics such as polyvinylchloride flexible
- Pesticides – the pesticides DDT (and its breakdown product DDE), methoxychlor, dieldrin, atrazine, and
- Phytoestrogens – naturally occurring chemicals in legumes, such as soybeans (e.g., genistein coumestrol)
Recent evidence has shown that a number of pharmaceutical and personal care products (commonly referred to as PPCPs) that are being discharged from sewage treatment facilities are acting as EDCs. PPCPs include human over-the-counter and prescription drugs, nutraceuticals (e.g., vitamins), and other consumer products (e.g., sunscreen, fragrances, cosmetics).
The endocrine system is a complex, chemical-based communication system that allows for an integrated control of cell metabolism, division and growth. This system uses chemical messengers called hormones that are produced by specialized cells within distinct endocrine glands (e.g., thyroid, pancreas). Following the proper signal, hormones are released into the blood stream and are carried by the blood to responsive tissues where they can bind at specific sites or cell receptors. This interaction causes biochemical responses in cells.
For more information about the endocrine system, see the US Environmental Protection Agency's Web page, "What Are Endocrine Disruptors."
Compelling evidence in a number of species of wildlife has shown that EDCs [at certain concentrations] may impact the endocrine system and cause developmental and reproductive problems. Evidence in humans has thus far remained elusive.
It is important to remember that the endocrine system is dynamic, designed to respond to stimuli by altering levels of its activity. Changes in endocrine activity do not mean that an adverse effect is inevitable. However, because the endocrine system plays a critical role in controlling the processes of reproduction and development, interfering with these processes by an inappropriately timed communication can have significant impacts. An exposure to a chemical at a critical point of development might have an effect that would not have occurred if the exposure had taken place at a different time during fetal development, childhood or adulthood. For some EDCs these impacts may be apparent not only in the exposed organism but in the next generation of this organism as well.
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Impacts to wildlife due to the presence of EDCs in the environment have been demonstrated; however, the ability of these chemicals, particularly at the levels found in the environment, to impact humans remains unresolved.
Equivocal results from a number of epidemiological (human) studies have led some scientists to claim that impacts of EDCs on humans are apparent. Other groups tend to be more cautious in interpreting these data, suggesting that humans likely face a greater risk from naturally occurring estrogens (e.g., phytoestrogens contained in soy or other food products) in their diet than they do from exposures to environmental contaminants.
The amount of scientific information available for EDCs is continually increasing. National research efforts funded by the National Institute of Environmental Health Sciences and the US Environmental Protection Agency (US EPA) are beginning to yield important information. International research efforts established by the European Union, Japan and Canada are also producing data that will be needed to regulate EDCs.
In 2000 the US EPA formally established the Endocrine Disruptor Screening Program, an effort designed to screen and test chemicals for their ability to act as EDCs. The US EPA’s goal is to use the information collected with the EDSP to conduct hazard assessments that will in turn be used for regulation of EDCs. In 2007 the US EPA proposed a draft list of 73 pesticide chemicals for Tier I screening:
The Endocrine Disruptor Screening Program has been criticized. Some individuals feel that the US EPA is moving too slowly and not paying enough attention to low dose exposures and the analysis of mixtures in their experimental designs. Animal rights groups have criticized the EDSP because of the large number of animals that the program will use for research purposes.
The Minnesota Department of Health (MDH) works with the Minnesota Department of Agriculture, Minnesota Pollution Control Agency, and others to track global research and scientific developments related to EDCs.
Much of the concern about EDCs in Minnesota (and other states) has focused on possible effects on endocrine systems in fish and other aquatic organisms in water. Fish and other aquatic organisms are exposed to chemicals from wastewater, runoff, or other sources. The Minnesota Department of Agriculture, Minnesota Pollution Control Agency, and US Geological Survey (USGS) monitor for chemicals in surface water and ground water, including some chemicals that have been implicated as EDCs. For information about water quality monitoring in Minnesota, see:
- Monitoring and Assessment for Agricultural Chemicals in the Environment, Minnesota Department of Agriculture
- MPCA Environmental Data Access, Minnesota Pollution Control Agency
- Minnesota Water Science Center: Water Resources of Minnesota, US Geological Survey
- National Water Information System: Web Interface - USGS Water Data for Minnesota, US Geological Survey
In the 1990's the MDH co-sponsored (with the University of Minnesota and MPCA) a meeting that brought together some of the country’s leading experts for a discussion about EDCs. In addition, the MDH prepared an article on EDCs for MN health care providers (Minnesota Medicine, January 2003 Issue), and recently we launched new web content to share information with the public and others.
The MDH is currently revising it's rules for contaminants in groundwater used for drinking:
As part of the rule revision, staff evaluate the potential for each chemical to act as an EDC. In cases where endocrine disruption is found to be the most sensitive endpoint, the available data are used to inform the development of a health-based values that are used by risk managers to protect public health.
For more information on EDCs, see:
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