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The Wingspread Statement
Rachel's Environment & Health Weekly - December 11/18, 1991
#263 - The Wingspread Statement (Part 1)
Chemicals In Environment Affect Sexual Development
In Wildlife And Humans?
Gradually during recent years a new body of knowledge
has developed showing that some chemicals in food and water can
mimic hormones and disrupt the development of living things like
fish, birds, and mammals, including their sexual development.
In some cases, the effects on wildlife have been
dramatic. For example, male herring gulls on Lake Ontario, exposed
to DDT and other organochlorine compounds, developed female sex
organs. Female-female pairing has been observed in herring gulls
on Lake Michigan and on Santa Barbara Island, California. Because
humans share the same basic mechanisms of growth and development
as wildlife, an increasing number of scientists has become concerned
that humans may already be affected without recognizing it.
In July of this year an international group of
21 scientists met at Wingspread in Racine, Wisconsin to assess what
is known about these matters. They have now released a "consensus
statement" containing information and opinions about the nature
and possible causes of these problems. The five-page statement is
called "Chemically Induced Alterations in Sexual Development:
The Wildlife/Human Connection."
Background
Hormones are produced by the endocrine system--a
bodily system consisting of specialized cells, tissues, and organs
that create and secrete (usually into the blood) organic chemicals
called hormones, which then regulate other kinds of cells in the
body. Particular hormones only affect particular cells that contain
"receptors" for those hormones. A small amount of a hormone
attaches to a "receptor site" and the hormone-receptor
pair then initiates a cascade of chemical changes, often with major
and far-reaching consequences.
The endocrine system shares with the nervous system
the job of adjusting the body's response to a changing external
environment. The nervous system copes with environmental changes
on an immediate basis, whereas the endocrine system copes with environmental
changes on a sustaining basis. For example, when the body gets cold,
the nervous system causes shivering, which raises the body's temperature.
But each month it is the endocrine system that starts the human
female menstrual cycle. In a developing fetus, it is the endocrine
system that regulates cell division and organ differentiation. The
endocrine system regulates pattern and timing of bird migration
and of hibernation in mammals. Examples of endocrine glands in humans
include the adrenal gland, pancreas, thyroid, pituitary, ovaries
and testes.
The scientists gathered at Wingspread last July
focused on the sex hormones--the androgens that make males look
and act like males and the estrogens that make females look and
act like females. The Wingspread Statement begins, "Many compounds
introduced into the environment by human activity are capable of
disrupting the endocrine system of animals, including fish, wildlife,
and humans. The consequences of such disruption can be profound
because of the crucial role hormones play in controlling development...."
"The following consensus was reached
by participants at the workshop.
"1. We are certain of the following:
"A large number of man-made chemicals
that have been released into the environment, as well as a few natural
ones, have the potential to disrupt the endocrine system of animals,
including humans. Among these are the persistent, bioaccumulative,
organohalogen compounds that include some pesticides (fungicides,
herbicides, and insecticides) and industrial chemicals, other synthetic
products, and some metals.[1]
"Many wildlife populations are already
affected by these compounds. The impacts include thyroid dysfunction
[impaired or abnormal functioning] in birds and fish; decreased
fertility in birds, fish, shellfish, and mammals; decreased hatching
success in birds, fish and turtles; gross birth deformities in birds,
fish and turtles; metabolic abnormalities [impaired or abnormal
use of energy, manufacture of tissue, or handling of resulting wastes]
in birds, fish, and mammals; behavioral abnormalities in birds;
demasculinization and feminization in male fish, birds, and mammals;
defeminization and masculinization of female fish and birds; and
compromised [impaired] immune systems in birds and mammals.
"The patterns of effects vary among
species and among compounds. Four general points can nonetheless
be made: (1) the chemicals of concern may have entirely different
effects on the embryo, fetus, or perinatal [meaning "near the
time of birth," from the 28th week of pregnancy through the
first week of life, in humans] organism than on the adult; (2) the
effects are most often manifested in offspring, not in the exposed
parent; (3) the timing of exposure in the developing organism is
crucial in determining its character and future potential; and (4)
although critical exposure occurs during embryonic development [from
conception through the end of the second month of pregnancy], obvious
manifestations [effects] may not occur until maturity.
"Laboratory studies corroborate the
abnormal sexual development observed in the field and provide biological
mechanisms to explain the observations in wildlife.
"Humans have been affected by compounds
of this nature, too. The effects of DES (diethylstilbesterol), a
synthetic therapeutic agent, like many of the compounds mentioned
[in footnote 1] are estrogenic [meaning they act like estrogen,
a family of female sex hormones]. Daughters born to mothers who
took DES now suffer increased rates of clear cell adenocarcinoma
[cancer], various genital tract abnormalities, abnormal pregnancies,
and some changes in immune responses. Both sons and daughters exposed
in utero [while in the uterus] experience congenital anomalies of
their reproductive system and reduced fertility. The effects seen
in in utero DES-exposed humans parallel those found in contaminated
wildlife and laboratory animals, suggesting that humans may be at
risk to those same environmental hazards as wildlife."
The Wingspread Statement goes on:
"2. We estimate with confidence that:
"Some of the developmental impairments
reported in humans today are seen in adult offspring of parents
exposed to synthetic hormone disruptors (agonists and antagonists)
released in the environment. The concentrations of a number of synthetic
hormone agonists and antagonists measured in the U.S. human population
today are well within the range and dosages at which effects are
seen in wildlife populations. [An agonist is a chemical that is
not a hormone but mimics a natural hormone; an antagonist interferes
with a natural hormone.] In fact, experimental results [in animals]
are being seen at the low end of current environmental concentrations
[in humans].
"Unless the environmental load of synthetic
hormone disruptors is abated and controlled, large scale dysfunction
at the population level is possible. The scope and potential hazard
to wildlife and humans are great because of the probability of repeated
and/or constant exposure to numerous synthetic chemicals that are
known to be endocrine disruptors...."
"[3]. Current models predict that:
"... Both exogenous (external source)
and endo-genous (internal source) androgens (male hormones) and
estrogens (female hormones) can alter the development of brain function.
"Any perturbation [disturbance] of the
endocrine system of a developing organism may alter the development
of that organism: typically these effects are irreversible. For
example, many sex- related characteristics are determined hormonally
during a window of time in the early stages of development, and
can be influenced by small changes in hormone balance. Evidence
suggests that sex- related characteristics, once imprinted, may
be irreversible."
The Wingspread statement then gives three reasons
why these predictions are subject to "many uncertainties:"
(1) effects of exposure of humans are not well understood, especially
exposure of embryos; (2) data on reproductive problems in wildlife
exist but data on behavior changes are not so readily available;
(3) the potency of many synthetic [human- created] estrogenic chemicals
is not well known. The British publisher, Elsevier Applied Science,
will publish a book on this subject by next fall. Until then, the
best source of information is Theodora E. Colborn and others, GREAT
LAKES GREAT LEGACY? available for $20.00 (plus $2.00 shipping) from:
World Wildlife Fund, P.O. Box 4866, Hampden Post Office, Baltimore,
MD 21211; phone (301) 516-6951.
For $3.00 plus stamped, self-addressed envelope,
we can send you the Wingspread statement itself.
----
[1] A footnote on page 1 of the Wingspread Statement
says, "Chemicals known to disrupt the endocrine system include:
DDT and its degradation products, DEHP (di(2-ethylhexyl)phthalate),
dicofol, HCB (hexachlorobenzene), kelthane, kepone, lindane and
other hexachlorocyclohexane congeners, methoxychlor, octachlorostyrene,
synthetic pyrethroids, triazine herbicides, EBDC fungicides, certain
PCB congeners, 2,3,7,8-TCDD and other dioxins, 2,3,7,8-TCDF and
other furans, cadmium, lead, mercury, tributyltin and other organo-tin
compounds, alkyl phenols (non-biodegradable detergents and anti-
oxidants present in modified polystyrene and PVCs), styrene dimers
and trimers, soy products, and laboratory animal and pet food products."
Descriptor terms: endocrine disrupters; racine,
wi; wi; wildlife; sexual development; endocrine system; fish; birds;
herring gulls; mammals; humans; reproductive hazards; reproductive
disorders; ddt; des; pesticides; herbicides; insecticides; fungicides;
theo colborn; wingspread statement;
Rachel's Environment & Health Weekly is a
publication of the Environmental Research Foundation, P.O. Box 5036,
Annapolis, MD 21403. Fax (410) 263-8944; Internet: erf@rachel.org.
Back issues available by E-mail; to get instructions, send Email
to INFO@rachel.org with the single word HELP in the message. Subscriptions
are free. To subscribe, E-mail the words SUBSCRIBE RACHEL-WEEKLY
YOUR NAME to: listserv@rachel.org NOTICE: Environmental Research
Foundation provides this electronic version of RACHEL'S ENVIRONMENT
& HEALTH WEEKLY free of charge even though it costs our organization
considerable time and money to produce it. We would like to continue
to provide this service free. You could help by making a tax-deductible
contribution(anything you can afford, whether $5.00 or $500.00).
Please send your tax- deductible contribution to: Environmental
Research Foundation, P.O. Box 5036, Annapolis, MD 21403-7036. Please
do not send credit card information via E-mail. For further information
about making tax-deductible contributions to E.R.F. by credit card
please phone us toll free at 1-888- 2RACHEL.
#263 - The Wingspread Statement (Part 2)
Major Challenge To 'Business As Usual'
An international group of 21 scientists[1] met
at Wingspread in Racine, Wisconsin in July, 1991 to discuss evidence
that chemicals in the environment are causing changes in the sexual
development of wildlife and conceivably in humans as well. (See
RHWN #263.) The group produced a five-page "consensus statement."
Sexual development in wildlife, as in humans,
is controlled by the endocrine system, a group of organs, tissues
and cells that secrete hormones; the hormones interact with other
cells, initiating chemical/biological reactions with far-reaching
consequences. Male hormones are called androgens; female hormones
are called estrogens.
It is now known that some chemicals disrupt the
endocrine system. The Wingspread statement identifies the following:
"Chemicals known to disrupt the endocrine system include: DDT
and its degradation products [DDE and DDD], DEHP (di(2-ethylhexyl)phthalate),
dicofol, HCB (hexachlorobenzene), kelthane, kepone, lindane and
other hexachlorocyclohexane congeners [forms], methoxychlor, octachlorostyrene,
synthetic pyrethroids, triazine herbicides, EBDC fungicides, certain
PCB congeners [forms], 2,3,7,8-TCDD and other dioxins, 2,3,7,8-TCDF
and other furans, cadmium, lead, mercury, tributyltin and other
organo-tin compounds, alkyl phenols (non- biodegradable detergents
and anti-oxidants present in modified polystyrene and PVCs), styrene
dimers and trimers, soy products, and laboratory animal and pet
food products."
In animals, and in humans, sexual characteristics
are established at a particular point during development in the
womb or egg. For example, Dr. Theodora Colborn of the World Wildlife
Fund (Washington, DC) points out that a single dose of dioxin, administered
to a pregnant rat at day 15 of the pregnancy--near the time when
gender is established--results in demasculinization and feminization
of male offspring.[2]
Samples of herring gulls from Lake Ontario collected
in 1975 and 1976 showed cellular and anatomical changes in embryos
and in newly hatched chicks that caused feminization of male chicks
and overdevelopment of female reproductive organs. Elevated concentrations
of DDE [a break down by product of DDT] and other residues were
found in eggs from the same population. To test whether these sexual
problems might be linked to the presence of the DDT, laboratory
experiments were conducted in which Western gull eggs were injected
with concentrations of DDT similar to those found in the Great Lakes
environment. Male chicks became feminized, developing ovarian tissue
and oviducts.[3]
What is becoming clear is that the older picture
of chemical toxicity underestimates the number and kinds of effects
that chemicals can have in fish, birds, and mammals. For decades,
U.S. regulatory officials have focused their attention almost exclusively
on cancer. Meanwhile, many of the chemicals that have been dumped
into the environment, and are now coursing through food chains,
cause many other detrimental effects besides cancer.
For example pesticides such as DDE, dieldrin,
lindane, mirex, toxaphene, and PCBs, block communication between
cells. Normal metabolism [energy use] and development of a cell
may be disrupted because movement of nutrients, electrolytes, and
hormones in and out of a cell is blocked by the presence of these
poisons.[4]
Furans, benzo[a]pyrene, 2,3,7,8-TCDD [dioxin],
DDE, dieldrin, HCB [hexachlorobenzene], lindane [beta-HCH], mirex,
toxaphene, and PCBs induce enzyme activity. [Enzymes are large protein
molecules that promote chemical activity in the body; the presence
of particular enzymes makes possible particular chemical reactions
that would not otherwise be possible.] When the enzyme activity
is induced, normal products of the endocrine hormonal system can
be released into the bloodstream. This can disrupt the role of steroid
hormones, affecting growth and sexual maturation.[4]
The structure of DDT and DDE are, themselves,
quite similar to estrogens and thus may mimic female hormones. In
addition, DDE induces enzymes that break down male hormones. Under
different circumstances, dioxin acts like an estrogen, or it may
act as an anti-estrogen (what causes the same chemical to have opposite
effects is not understood). [4]
At one Superfund site where data are available,
humans are experiencing abnormalities of sexual development. At
the Brio site south of Houston, Texas, where a housing development
was built atop a chemical dump, girls 4 to 5 years old have developed
pubic hair and enlarged breasts. One child (now four years old)
was born without any genital organs; chromosome tests revealed that
this is a male child, though he has a birth canal. This information,
and other data about abnormal sexual development of children at
the Brio site, is contained in a unique database of information
that resulted from a health survey of the community by a local group
(HELP) and by the Environmental Health Network (EHN) in Harvey,
Louisiana.[5] Such surveys--providing an unusually valuable source
of information about health problems near chemical dumps--are under
way in several Superfund communities, looking for patterns of problems,
including the kinds the Wingspread statement warns of.
The Wingspread statement presents a major new
challenge to advocates of "business as usual." The participants
in the conference represent 17 different fields of scientific inquiry.
They have many thousands of data points on which they have based
their conclusions. If they are right, we are all being exposed,
on a daily basis, to chemicals that threaten out reproductive health,
and the health of our offspring.
Because hormones and hormone disrupters do their
work at extremely low concentrations, the only "safe"
dose of an endocrine-system disrupter is zero. Thus any new sources
of these chemicals should be aggressively discouraged while we figure
out how to minimize exposure to the quantities of these chemicals
already in the environment.
---
[1] Participants in the Wingspread meeting included
the following individuals (whose institutional affiliations are
given for identification purposes only): Dr. Howard A. Bern, Professor
of Integrative Biology (emeritus) and Research Endocrinologist,
University of California-Berkeley; Dr. Phyllis Blair, Professor
of Immunology, University of California-Berkeley; Sophie Brasseur,
Marine Biologist, Research Institute for Nature Management, Texel,
The Netherlands; Dr. Theo Colborn, Senior Fellow, World Wildlife
Fund, Washington, DC; Dr. Gerald R. Cunha, Developmental Biologist,
University of California-San Francisco; Dr. William Davis, Research
Ecologist, Environmental Research Laboratory, U.S. Environmental
Protection Agency, Sabine Island, FL; Dr. Klaus D. Dohler, Director,
Research, Development & Production, Phar-ma Bissendorf Peptide
GmbH, Hannover, Germany; Glen Fox, Contaminants Evaluator, National
Wildlife Research Center, Environment Canada, Quebec, Canada; Dr.
Michael Fry, Research Faculty, Department of Avian Sciences, University
of California-Davis; Dr. Earl Gray, Section Chief, Developmental
and Reproductive Toxicology Division, Health Effects Research Laboratory,
U.S. Environmental Protection Agency, Research Triangle Park, NC;
Dr. Richard Green, Professor of Psychiatry in Residence, School
of Medicine, University of California-Los Angeles; Dr. Melissa Hines,
Assistant Professor in Residence, School of Medicine, University
of California-Los Angeles; Timothy J. Kubiak, U.S. Fish and Wildlife
Service, East Lansing, MI; Dr. John McLachlan, Director, Division
of Intramural Research, National Institute of Environmental Health
Sciences, Research Triangle Park, NC; Dr. J.P. Myers, Director,
W. Alton Jones Foundation, Charlottesville, VA; Dr. Richard E. Peterson,
Professor of Toxicology and Pharmacology, School of Pharmacy, University
of Wisconsin-Madison; Dr. P.J.H. Reijnders, Head, Section of Marine
Mammology, Research Institute for Nature Management, Texel, The
Netherlands; Dr. Ana Soto, Associate Professor, Tufts University
School of Medicine, Boston, MA; Dr. Glen Van Der Kraak; Assistant
Professor, University of Guelph, Ontario, Canada; Dr. Frederick
vom Saal, Professor, Division of Biological Sciences, University
of Missouri-Columbia; Dr. Pat Whitten, Assistant Professor, Department
of Anthropology, Emory University, Atlanta, GA.
[2] David J. Hanson, "Dioxin Toxicity: New
Studies Prompt Debate, Regulatory Action," C&EN [CHEMICAL
& ENGINEERING NEWS] August 12, 1991, pg. 13.
[3] Theodora E. Colborn and others, GREAT LAKES
GREAT LEGACY? (Washington, DC: Conservation Foundation, 1990), pg.
139.
[4] Theodora E. Colborn and others, cited above,
pg. 142.
[5] For more information about the Brio site,
contact HELP: 10904 Scarsdale Boulevard, M263, Houston, TX 77089;
phone (713) 992-1867. For advice about health surveys, contact Linda
King, Environmental Health Network, P.O. Box 1628, Harvey, LA 70058;
phone (504) 362-6574.
Descriptor terms: endocrine disrupters; racine,
wi; wi; wildlife; sexual development; endocrine system; fish; birds;
herring gulls; mammals; humans; reproductive hazards; reproductive
disorders; ddt; des; pesticides; herbicides; insecticides; fungicides;
theo colborn; world wildlife fund; superfund; brio; environmental
health network; wingspread statement;
Rachel's Environment & Health Weekly is a
publication of the Environmental Research Foundation, P.O. Box 5036,
Annapolis, MD 21403. Fax (410) 263-8944; Internet: erf@rachel.org.
Back issues available by E-mail; to get instructions, send Email
to INFO@rachel.org with the single word HELP in the message. Subscriptions
are free. To subscribe, E-mail the words SUBSCRIBE RACHEL-WEEKLY
YOUR NAME to: listserv@rachel.org NOTICE: Environmental Research
Foundation provides this electronic version of RACHEL'S ENVIRONMENT
& HEALTH WEEKLY free of charge even though it costs our organization
considerable time and money to produce it. We would like to continue
to provide this service free. You could help by making a tax-deductible
contribution(anything you can afford, whether $5.00 or $500.00).
Please send your tax- deductible contribution to: Environmental
Research Foundation, P.O. Box 5036, Annapolis, MD 21403-7036. Please
do not send credit card information via E-mail. For further information
about making tax-deductible contributions to E.R.F. by credit card
please phone us toll free at 1-888-2RACHEL.
Further Reading
Reproductive health
in Humans and Wildlife: are adverse trends associated with environmental
chemical exposure?
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