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Endocrine Disruptors Research
Research Programs
Scientific evidence suggests that environmental exposure to some man-made chemicals may result in disruption of the endocrine (hormone) system in humans and wildlife. A variety of chemicals have been found to disrupt the endocrine system of laboratory animals, and there is strong evidence that chemical exposure has been associated with adverse developmental and reproductive effects in fish and wildlife in particular locations. The relationship of human diseases of the endocrine system and exposure to environmental contaminants, however, is poorly understood.
The Endocrine Disruptor Research Program (EDRP) in EPA's Office of Research and Development (ORD) is providing the methods, models, and tools needed to improve our understanding of the potential risks to human health and wildlife from chemicals that disrupt the endocrine system, that is endocrine disrupting chemicals (EDCs). EPA's scientists and their grant recipients in the multidisciplinary research program are:
- Evaluating the effects of EDCs on people and wildlife and determining how people and ecosystems become exposed to these chemicals
- Developing tools to integrate effects and exposure data related to human health and the environment
- Developing risk management approaches to mitigate exposures in human and wildlife populations.
The Endocrine Disruptor Research Program is focused on three long-term goals:
Long-Term Goal 1:
To provide a better understanding of the science underlying the effects, exposure, assessment and risk management of endocrine disruptors.
Long-Term Goal 2:
To determine the extent of the impact of endocrine disruptors on humans, wildlife, and the environment.
Long-Term Goal 3:
To support EPA's screening and testing program for endocrine disruptors by developing in vitro and in vivo assays that evaluate the potential for chemicals to cause endocrine-mediated effects in humans and wildlife.
Long-Term Goal 1
To provide a better understanding of the science underlying the effects, exposure, assessment, and risk management of endocrine disruptors. Research in this area includes determining dose-response relationships, the effects of exposure to multiple endocrine disruptors, major sources of exposure, and approaches for assessing and managing risks. Research includes:- Determining the classes of chemicals that act as endocrine disruptors and their potencies
- Characterizing the biochemical mechanisms through which chemicals act
- Determining dose-response relationships, in particular at low levels of exposure
- Developing approaches to assess cumulative risk, including ways to take into consideration exposures to multiple chemicals that may act through similar or different biochemical mechanisms
- Developing approaches for extrapolating results across animal species
- Developing indicators of exposures and analytical methods for detecting certain EDCs
- Identifying key factors that influence human exposure and environmental sources
- Developing tools for risk reduction and mitigation strategies
Science questions being addressed include:
- What are the dose-response characteristics in the low-dose region?
- What extrapolation tools are needed?
- What are the effects of exposure to multiple EDCs and will a toxicity equivalent factor approach (similar to that used for a few other classes of chemicals) be applicable?
- How can unreasonable risks be managed?
- What approaches are needed to assess risks to humans and wildlife?
The science is providing a sound scientific foundation for environmental decision-making. The research is:
- Being used to evaluate manufacturers' data on chemicals submitted to EPA and other data from the scientific literature to develop integrated risk assessments on chemicals that interfere with the endocrine system.
- Being applied in field studies by EPA and others to determine the levels of exposure to EDCs in environmental media and to determine the extent to which and efficacy with which they could be reduced or eliminated (see Long Term Goal 2).
Long-Term Goal 2
To determine the extent of the impact of endocrine disruptors on humans, wildlife, and the environment. Research is determining:
- What effects are occurring in human and wildlife populations
- What chemical classes are of the greatest concern
- What ambient levels of exposure exist
- What risk management approaches are most effective in preventing or reducing exposures
Science Questions being addressed include:
- How and to what degree are human and wildlife populations are exposed to EDCs?
- What effects are occurring in exposed human and wildlife populations?
- What are the chemical classes of interest and their potencies?
- What are the major sources and environmental fates of EDCs?
The methods, models, and tools developed under Long-Term Goal 2 and elsewhere are being applied in field studies to assist EPA and others in characterizing the impact of environmental mixtures of EDCs on humans, environmental media, and aquatic organisms.
Long-Term Goal 3
To support EPA's screening and testing program for endocrine disruptors by developing in vitro and in vivo assays that evaluate the potential for chemicals to cause endocrine-mediated effects in humans and wildlife. Research includes:
- Improving existing and/or developing new protocols to detect the endocrine activity of chemicals
- Developing a suite of in vitro and in vivo assays for use in Tier 1 and Tier 2 of the Agency's Endocrine Disruptors Screening Program (EDSP)
- Focusing on estrogen, androgen, thyroid, steroidogenesis, and aromatase pathway
Science Question being addressed:
- Do our testing guidelines adequately evaluate potential endocrine-mediated effects?
The assays developed in this research are being validated through EPA's Office of Science Coordination and Policy within the Office of Prevention, Pesticides, and Toxic Substances and the Organization for Economic Cooperation and Development (OECD) for use in screening and testing of chemicals for endocrine activity in the US and internationally.