Potential of
Chemicals to Affect the Endocrine System
In recent years, increasing scientific and
public attention has been focused on the potential effects of synthetic
chemicals on the hormone system. In March 1996, Theo Colborn, Dianne Dumanoski,
and John Peterson Myers published a book entitled Our Stolen Future that
addressed this issue. According to the book, hormone disrupting chemicals are
widespread and can cause adverse effects even at low levels, resulting in
potentially serious risks to the environment and public health.
This document summarizes EPA's
understanding of this issue and the action it is taking, as well as discussing
some of the book's recommendations.
1. What is the
endocrine system, and what are endocrine disruptors?
The endocrine system consists of a set
of glands and the hormones they produce that help guide the development,
growth, reproduction, and behavior of animals including human beings. Some of
the endocrine glands include the pituitary, thyroid, and adrenal glands, the
female ovaries and male testes. Hormones are chemicals, produced by endocrine
glands, that travel through the bloodstream and cause responses in other parts
of the body. Examples of hormones include adrenaline, which helps stimulate
physical activity, and estrogen, which is essential for female reproductive
function. Hormones can produce both positive and negative effects. For
example, some types of breast cancer are exacerbated by estrogen, but studies
also indicate that estrogen has a protective effect in combating heart disease
and osteoporosis-related fractures.
Chemicals that interfere with the normal
functioning of this complex system are known as "endocrine
disruptors." Disruption of the endocrine system can occur in various
ways.
For example, some chemicals may mimic a
natural hormone, fooling the body into over-responding to the hormone. Other
chemicals may block the effects of a hormone in parts of the body normally
sensitive to it. Still others may directly stimulate or inhibit the endocrine
system, leading, to overproduction or underproduction of hormones. Certain
drugs are used to intentionally cause some of these effects, such as birth
control pills.
2. What is EPA's
position on this issue, and what is EPA doing to address endocrine disruptors?
EPA is concerned about the growing body
of evidence that some man-made chemicals may be interfering with normal
endocrine system functioning in humans and other animals. Considerable
scientific uncertainty remains, however, as to which chemicals may be
involved, patterns of exposure, mechanisms of action in humans and wildlife,
and the best means for testing to predict or screen for these effects. EPA is
investing significant resources to resolve these uncertainties.
In addition to conducting research, EPA
has taken and is taking a number of steps to reduce chemical risks. The Agency
has already banned the use in the United States of a number of the more
environmentally persistent chemicals that have raised concerns about possible
hormonal effects (PCBs, and such organochlorine pesticides as DDT, chlordane,
aldrin/dieldrin, endrin, kepone, toxaphene, and 2,4,5-T) and is working with
the international community to limit production and use of these chemicals
worldwide. The Agency is also revising its testing guidelines for revaluating
the effects of pesticides and toxic substances on reproduction and the
developing fetus, which will enable EPA scientists to more readily identify
chemicals with hormone-disrupting effects.
EPA continues to encourage actions to
reduce unnecessary chemical exposure and use, and more generally, to promote
pollution prevention. For example, EPA is working with pesticide user groups
to reduce pesticide use and risk, and encouraging the design and use of safer
industrial chemicals and pesticides. EPA is also implementing the Worker
Protection Standard which requires appropriate protective equipment and
other measures to reduce exposure to pesticides in agriculture. Through
expansion of the Toxics Release Inventory, the Agency is providing the public
with more information and fostering constructive dialogue between citizens and
industry on reducing and preventing chemical releases into the environment.
Other informational efforts include the development of practical guides for
consumers who wish to reduce their exposure to pesticides in their homes,
schools, and other settings.
3. Specifically,
what research efforts is EPA undertaking to learn more about endocrine
disruptors?
EPA has developed its own research
strategy and is working with other agencies to develop a comprehensive
research strategy for the Federal Government. This effort is being expanded in
the hope that an international strategy can be established, coordinated with
both the public and private sectors.
The goals of EPA's overall research
strategy are to (1) establish priorities for the allocation of the Agency's
research funds; (2) serve as a basis for coordination and communication among
other principally involved Federal agencies; and (3) provide a basic research
framework for regulatory programs within EPA.
With respect to specific projects,
research on various aspects of hormone disruptors has been ongoing at EPA's
laboratories and in collaboration with non-EPA scientists. Some of the work
has looked at the reproductive effects of certain pesticides, evaluated human
sperm count and fertility relationships, and studied reproductive problems
among alligators and fish populations in Lake Apopka, Florida. EPA will
continue to support relevant research through its grants program.
EPA is also collaborating in two major
studies being conducted by the National Cancer Institute and National
Institute of Environmental Health Sciences: the Long Island Breast Cancer
Study, which is evaluating various environmental and occupational factors in
breast cancer, and the Agricultural Health Study, which will assess pesticide
exposure and health risks, including potential reproductive effects and
effects on child growth and development.
Finally, at the request of EPA's Office
of Water, the National Research Council of the National Academy of Sciences
(NAS) has convened a multi disciplinary expert committee to review the
scientific literature on hormone-related chemicals in the environment. NAS
expects to complete its work in the summer of 1997. In the interim, EPA is
developing an agency-wide position paper on environmental hormones, which will
be issued in early 1997.
4. Does EPA
require testing of chemicals for endocrine effects?
EPA routinely screens new industrial
chemicals prior to their introduction into commerce and seeks to control any,
including suspected hormonal disruptors, which may pose an unreasonable risk
to human health and the environment. New pesticides are routinely tested in
animals for effects on reproduction, fertility, and the developing fetus
before they are approved for use. Older pesticides are tested as part of EPA's
ongoing re-registration program, a comprehensive reevaluation of all
pesticides first approved before 1984. The growth and development of offspring
are also evaluated, including an assessment of birth defects or other
abnormalities. Although these tests are not specifically designed to identify
endocrine disruption, they can detect certain reproductive and developmental
effects which may result from endocrine disruption.
EPA's Office of Prevention, Pesticides,
and Toxic Substances has recently proposed revised testing guidelines for
evaluating the developmental and reproductive effects of pesticides and
industrial chemicals. Although current tests can detect some hormonal effects
of chemicals, the proposed revisions would increase the sensitivity of the
tests, thereby increasing the Agency's capacity to screen for potential
effects of chemicals on mating, fertility, pregnancy, delivery, and care of
young by laboratory animals. The revised tests will also look at effects on
reproductive organ structure and functioning in parents and offspring.
Examples include an examination of female hormonal cycling and male sperm
count, shape, and activity.
The Agency has solicited public comment
on these guidelines, which will be required in future testing under both the
Toxic Substances Control Act (TSCA) and the Federal Insecticide, Fungicide and
Rodenticide Act (FIFRA).
5. Does EPA agree
with the recommendations in Our Stolen Future?
EPA agrees with many of the concerns
raised in Our Stolen Future and has already taken steps to address a number of
its recommendations. We agree, for example, that pesticides should only be
used when necessary and are working with other agencies and groups to reduce
pesticide use and risk. These efforts include promoting Integrated Pest
Management programs and safer pest control alternatives. We are also working
to implement recommendations from the National Academy of Sciences and others
to provide greater assurance that our safety standards protect vulnerable
populations, especially infants and young children, and improving our ability
to screen for potential endocrine effects. We are implementing new legislation
that strengthens our efforts in this regard and are developing an expanded
research agenda. Finally, as the book points out, many of the chemicals of
greatest concern have already been banned in the U.S. but may continue to be
used in other countries. We have taken a leadership role in international
efforts to eliminate such persistent organic pollutants.
The book also contains many practical
suggestions and recommendations for people seeking to reduce their exposure to
chemical risks. As with all suggestions affecting consumer choice, the final
decisions will appropriately be made by individuals. Thus, the Agency does not
necessarily believe that all of the book's suggestions will be equally
practical or appropriate for every person.
6. Does EPA
regulate endocrine disruptors in drinking water? Does EPA require any testing
for the presence of endocrine disruptors in public water systems and reporting
of the results?
EPA regulates certain chemicals that are
suspected of being endocrine disruptors in drinking water. The drinking water
regulations contain testing, reporting and public notification requirements
for regulated contaminants. Regulation of potential endocrine disruptors under
the Safe Drinking Water Act (SDWA) generally has been based on adverse health
effects such as cancer and other chronic adverse effects. Most regulatory
levels are protective for the individual chemicals but uncertainty remains in
specific cases and for the cumulative effect of multiple exposures.
Maximum contaminant levels (MCLS) have
been established under the SDWA for pesticides (e.g. chlordane, DDT, endrin,
toxaphene, lindane, atrazine, simazine), non-pesticide organics (e.g., PCBs,
dioxin, PAHs) and inorganic chemicals (e.g., mercury, lead) that are suspected
endocrine disruptors.
7. Does EPA
recommend that people drinking from private wells test their water for the
presence of endocrine disruptors, and if so, how should they do that?
The Safe Drinking Water Act (SDWA) does
not regulate private wells. However, EPA recommends that if a private well
owner suspects that there is a potential for contamination, the water should
be tested for those contaminants of potential concern. For example, a shallow
well in an agricultural area with heavy pesticide use should be tested for the
presence of those pesticides of concern.
Private well owners can request
assistance from the appropriate State authority to have their water tested for
the presence of those potential endocrine disruptors that are currently
regulated in drinking water. There are laboratories throughout the United
States certified to conduct testing for regulated drinking water contaminants.
States can provide information on laboratories that are certified. Certified
laboratories should be used to ensure that the testing results are reliable.
8. Is bottled
water in plastic containers safe to drink?
The Food and Drug Administration (FDA)
regulates bottled water, not EPA. FDA investigates the potential toxicity of
leaching chemicals and establishes safe levels for contaminants in bottled
water. There is currently no indication that contaminants from leaching or
from the water source are a problem in bottled water.
Therefore, EPA believes that bottled
water is generally safe to drink. [Further questions about bottled water
should be referred to FDA officials: Terry Troxell (202) 205-5321, or Mike
Kashtock (202) 205-4681]
9. Does EPA
recommend the use of water purification devices if people are worried about
contamination?
EPA believes that a public water supply
or a private well that meets the Federal drinking water standards provides
drinking water which is safe for human consumption. Individuals should make a
judgement as to whether they are willing to invest resources on a water
purification device for additional peace of mind.
10. Am I at risk
of being exposed to PCBs and DDT/DDE by eating fish?
The fish we eat can come from many
different environments. Some fish are harvested by ocean fishing vessels;
others are freshwater fish caught in lakes, rivers, and streams, or raised in
ponds on aquaculture establishments. Most fish sold in the grocery store and
in restaurants come from the ocean and are much less likely to have detectable
levels of PCBs and DDT/DDE than freshwater fish.
The U.S. Food and Drug Administration
(FDA) monitors the safety of fish sold at retail establishments and those
shipped in interstate commerce. When PCBs and DDT/DDE are detected in
commercially sold species, they usually occur at low levels that should not be
of concern to the consumer.
Freshwater fish caught by sport
fishermen or by those who subsist on freshwater fish in areas where PCBs have
historically been found in the environment sometimes contain levels exceeding
federal limits established to protect the public. The greatest potential of
exposure to these chemicals in fish come from recreational fishing in areas
where PCBs and DDT/DDE are found at elevated levels. People who catch and eat
freshwater fish should ensure that the waters they are fishing in are safe
from environmental hazards by checking with their state authorities. Local
advisories are sometimes implemented if state authorities feel that it is
unsafe to consume high quantities of fish from a certain source.
Usually these advisories contain
recommendations to reduce the risk of chemical exposure from fish caught in
contaminated waters. These recommendations include proper cleaning procedures,
such as removing the skin and fatty tissues where chemicals may concentrate.
11. Should people
avoid animal fats in their diet?
EPA and other public health experts
agree that people can best protect their health by eating a varied and
balanced diet, eating more fruits and vegetables, and reducing excess fat and
calories. This advice has been consistently reaffirmed in scientific studies
and reports, most recently in the report from the National Academy of Sciences
(NAS) on Carcinogens and Anticarcinogens in Food, published last month.
Controlling fat and calories, while increasing fruit and vegetable
consumption, appears to have many advantages independent of potential hormonal
effects, for example in reducing risk of heart disease and cancer.
Most health and nutrition experts advise
trimming excess fat from meat and poultry as a general practice. Since some
chemical residues concentrate in fatty tissues, people who wish to minimize
their exposure to these residues should follow this advice.
12. Should people
be concerned about pesticides in food?
As pointed out by the NAS and others,
pesticide residues in food are generally present at low levels unlikely to
present significant risks. Individuals who wish to minimize pesticide residues
can take steps to reduce traces of residues in the food they consume. EPA
advises rinsing fruits and vegetables thoroughly with water, scrubbing them
with a brush, and peeling when appropriate. Cooking and baking will reduce
residues of some pesticides even further.
Many people prefer organically grown
food for a number of reasons. EPA does not think that consumers need to switch
to organic food based on dietary risk concerns, but choice of organic food is
a personal matter for consumers to decide for themselves.
13. Should people
stop using plastic containers and plastic wrap when storing or heating up food?
The Food and Drug Administration (FDA)
regulates food packaging materials. Plastics for food packaging undergo tests
to determine the extent of migration and the potential toxicity of leaching
chemicals. These data are reviewed by FDA prior to marketing, and specific
regulations are developed listing the chemicals that are permitted for use in
contact with food. FDA has found currently approved food packaging plastics to
be safe, primarily because they migrate to food in only trivial amounts.
FDA is continuing to investigate the
migration levels of certain food packaging materials into food and will take
additional regulatory action should the data indicate potential health risks.
Because food package components are
tested under conditions reflecting each container's intended use, it is
important to use plastic food containers only as intended. Food should be
heated only in containers that are clearly intended for use at elevated
temperatures. Packaged food with labeling instructions for heating in the
package or storage containers sold for use in microwave ovens are two examples
of such containers. [Further questions about plastic food packaging should be
referred to George Pauli of the FDA at (202) 418-3100.]
14. Will frequent
hand washing reduce exposure to endocrine disruptors?
As a matter of good hygiene and proper
pesticide use, EPA advises individuals to wash their hands after applying any
pesticide and before handling food. This practice will help minimize
unnecessary exposure and prevent contamination of foods with chemical or
microbial agents. It is also important to follow other precautions on product
labels carefully, for example, to wear gloves when directed to do so on the
label, and to store pesticides and other household chemicals out of the reach
of children.
15. Should
consumers avoid using pesticides?
Pesticides are designed to be
biologically active and should never be used unless necessary. Pesticides have
risks as well as benefits, and it is important to use them properly. When they
are used according to label directions, EPA believes pesticides are generally
safe. To help consumers make more informed decisions about pesticide use, the
Agency has developed several brochures which contain a great deal of practical
information. The best general source of information is EPA's Control and
Pesticide Safety, which tells people how to decide whether pesticides are
needed, and if so, how to select the right product and use it most safely. The
Healthy Lawns, Healthy Environment, brochure includes many practical tips
about how homeowners can have an attractive lawn while using little or no
pesticides. Finally, EPA's booklet on Pest Control in the School Environment
describes many non-chemical ways to deal with typical pest problems found in
schools and other indoor settings. These publications are available free from
the National Service Center for
Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH
45242-2419 (Telephone 513-891-6561 or Fax 513-891-6685).
Consumers with questions about specific
pesticides can call the National
Pesticides Telecommunications Network (NPTN) toll-free. NPTN is
available to anyone in the United States, Puerto Rico and the Virgin Islands
(7 days/week, except holidays, 6:30 a.m. to 4:30 p.m. Pacific Time) at 1
800-858-7378.
16. Should
golfers be concerned about pesticides used on golf courses?
The Agency is working with the golf
industry as well as many other pesticide user groups to reduce the risks from
the use of pesticides through the Pesticide Environmental Stewardship Program
(PESP). PESP is a broad effort by EPA, USDA, and FDA to work with pesticide
users and others to reduce pesticide use and risk in both agricultural and
nonagricultural settings by developing use/risk reduction strategies that
include reliance on biological pesticides and increasing adoption of
Integrated Pest Management (IPM) programs.
The Golf Course Superintendents
Association of America and the Professional Lawn Care Association are both
partners in PESP through the New York Audubon Society's Cooperative Sanctuary
Program. The Sanctuary Program encourages property owners, both corporate and
private, to improve wildlife habitat on their property and to adopt IPM
programs to control problems that may occur. Through this partnership, we aim
to reduce the risk and use of pesticides. in the turfgrass industry,
specifically in golf course planning and siting, design, construction,
maintenance and facility operations.
Golfers who seek to reduce their
exposure to pesticides may wish to ask if the golf course follows IPM
practices and what pesticides are used. Some golf courses may have a list of
pesticides they use and when they are applied. Golfers may want to schedule
their play to avoid recent pesticide applications.
17. What is
Integrated Pest Management (IPM)?
IPM is an effective and environmentally
sensitive approach to pest management that relies on a combination of common
sense practices. IPM weighs costs, benefits, and impacts on health and the
environment, thus identifying the most suitable way to control pests. Options
include prevention, monitoring, mechanical trapping devices, natural
predators, biological pesticides, and, if appropriate, chemical pesticides.
The goal is to get the best long-term results with the least disruption of the
environment.
18. Should
parents try to keep infants and children from playing with or chewing on plastic
objects?
raises important questions about the
relationship of chemicals used in plastics and possible effects on the
endocrine system, but the book acknowledges that much more research is
necessary. At present, EPA does not believe the scientific evidence supports
this recommendation, which would also be very difficult to achieve in
practical terms.
19. Does EPA
agree with the recommendations to a) greatly reduce the number of chemicals on
the market; b) reduce the number of chemicals in a product; c) disallow products
if we do not understand how they degrade in the environment?
EPA does not necessarily equate fewer
chemicals in commerce with greater safety for public health and the
environment. One can not arbitrarily restrict the numbers of chemicals on the
market or in products. Chemicals in products have a function in the
performance of the product or else they wouldn't be there. Fundamentally,
EPA's role is to encourage the use of safer chemicals and processes in the
operations of the industrial sector. Clearly our success depends on industry
incorporating the principles of pollution prevention into its basic
technological and developmental decisions. The majority of existing chemicals
do not pose significant risk to human health or the environment in their
current uses and many new chemicals appear to be safer than the ones that they
displace.
EPA's new chemicals program under TSCA
plays a major role in screening chemicals before they reach the marketplace to
ensure that use of commercial chemicals will not pose unreasonable risks to
human health or the environment. For chemicals already in commerce, we are
increasingly recognizing the advantages of looking at clusters of chemicals,
rather than single chemicals, in evaluating alternative products and
processes, and we are working cooperatively with a variety of industries to
encourage them to turn to products and processes that are safer and more
effective. We believe that our new chemical review process, which scrutinizes
every new chemical entering the market, is sophisticated enough to prevent
substantial harm from known types of hazards. We need to better understand
what types of chemicals disrupt endocrine function, but we believe we have an
adequate legal and regulatory framework to deal with these risks.
20. Does EPA
think it is realistic for society to use dramatically lower amounts of
pesticides?
We believe substantial progress has been
made in the U.S. to reduce reliance on chemical pesticides, but agree that
more can be done, especially as safer pest management tools are developed and
approved, for use. EPA is accelerating the registration of biological
pesticides and chemical pesticides that are safer than products currently in
use. In 1993 EPA, the Food and Drug Administration, and the U.S. Department of
Agriculture entered into a joint effort. to expand the use of Integrated Pest
Management by the year 2000 to 75% of the crop acres in agriculture, the
sector of our society which uses the most pesticides. Key to the success of
this effort is the assurance that farmers will be able to meet their pest
control needs economically and efficiently. When this effort is complete, the
Agency expects there will be not only less pesticide use, but safer and
smarter use as well.
In addition, as described above, we are
working to reduce nonagricultural pesticide use and risk through the PESP
program and efforts to provide homeowners and others with practical
information on lawn care and effective pest control strategies in the home and
other nonagricultural settings.
U.S. Environmental Protection
Agency
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