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Rachel's Environment & Health News
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#665 - Cause for Precautionary Action, August 26, 1999
After four years of study, the National
Research Council (NRC) of the National
Academy of Sciences on August 4 published
its report on hormone-disrupting chemicals
in the environment.[1] The report
represents a consensus statement by the
NRC's Committee on Hormonally Active
Agents in the Environment, a committee
made up of 16 scientists,[2] including
some who are closely aligned with the
chemical industry.
The Committee had been asked by Congress
and by U.S. Environmental Protection
Agency (EPA) to evaluate the hazards posed
by hormone-disrupting chemicals in the
environment. Dozens, perhaps hundreds, of
common industrial chemicals are known to
interfere with hormones under some
conditions, so the stakes are high.
Hormones are naturally-occurring chemicals
that circulate at very low levels in the
blood stream of all vertebrate animals
including reptiles, amphibians, fish,
birds and mammals. (Vertebrates are
animals with a backbone.) In all
vertebrate species, hormones act as
chemical messengers and as switches,
turning on and off bodily systems that
control growth, development, learning and
behavior. Hormones start affecting every
animal shortly after it begins life as a
fertilized egg. Hormones control growth
and development prior to birth or
hatching, and hormones continue to
influence behavior throughout life.
Hormones tell bears when to hibernate,
tell salmon when to return to their
spawning grounds, and cause women to
menstruate every 28 days or so. Hormones
profoundly affect the nervous system, the
reproductive system, and the immune
system. Naturally-occurring hormones are
also implicated in some forms of cancer,
such as female breast cancer which is
widely believed to be linked to a woman's
lifetime exposure to estradiol (estrogen),
the main female sex hormone.[1,pg.197]
Because of the importance of hormones in
the life of all vertebrates, industrial
chemicals that can interfere with hormones
are exceedingly important from a public
health perspective. They also represent
major embarrassments and liabilities for
the corporations that put such chemicals
into common use without adequate safety
tests. The presence of synthetic
[human-created] hormone-disrupting
chemicals in air, water, sediments, soil
and food also represents a major failure
of the U.S. Public Health Service and the
U.S. Environmental Protection Agency.
Furthermore, if hormone-disrupting
chemicals in the environment are
identified as an important problem, then
someone may be held responsible (at least
in the court of public opinion) and
confidence in government and in the
chemical industry may drop below their
present subterranean levels. Therefore,
there is powerful pressure from many parts
of "the Establishment" to deny the
existence of this problem. NEW YORK TIMES
writer Gina Kolata has distinguished
herself as the main spokesperson for the
deniers.[3]
Despite the highly-charged nature of the
subject, and despite the presence of
chemical industry representatives on the
committee, the NRC's consensus report is
rather strong, as indicated by these
verbatim quotations:
"Adverse reproductive and developmental
effects have been observed in human
populations, wildlife, and laboratory
animals as a consequence of exposure to
HAAs [hormonally active agents]."[1,pg.3]
"Most notable are the adverse reproductive
and developmental effects that have been
observed in birds such as cormorants,
herrings gulls, Caspian terns, and bald
eagles that feed on contaminated fish,
which have led to drastically lowered
reproductive success and population
declines."[1,pg.9]
"Laboratory studies using male and female
rats, mice, and guinea pigs, and female
rhesus monkeys have shown that exposure of
these animals during development to a
variety of concentrations of certain HAAs
(e.g., DDT, methoxychlor, PCBs, dioxin,
bisphenol A, octylphenol, butyl benzyl
phthalate (BBP), dibutyl phthalate (DBP),
chlordecone, and vinclozolin) can produce
structural and functional abnormalities of
the reproductive tract."[1,pg.3]
"There is evidence of suppression of the
immune system by exposure to
organochlorines (predominantly PCBs) in
birds in the Great Lakes region. There is
also evidence of suppression of innate and
acquired immune responses in seals fed
fish from the PCB-contaminated Baltic Sea.
Such immunosuppression is believed to be
the reason for the increased incidences of
bacterial and viral infections in seals in
similarly contaminated waters."[1,pg.5]
"Environmental HAAs [hormonally active
agents] probably have contributed to
declines in some wildlife populations,
including fish and birds of the Great
Lakes and juvenile alligators of Lake
Apopka [in Florida], and possibly to
diseases and deformities in mink in the
United States, river otters in Europe, and
marine mammals in European
waters."[1,pg.6]
"Synthetic HAAs [i.e., HAAs released by
chemical corporations] have been detected
in all environmental media [air, water,
sediments, and soil], although
concentrations of some compounds, such as
PCBs and DDT, have declined in some
regions, because their use has been
discontinued in those countries. However,
those HAAs and others can persist in some
media, such as sediments, for years and
can contaminate areas far removed from the
original site of contamination (e.g., via
atmospheric transport)."[1,pg.7]
"Human dietary intake of synthetic HAAs
remains substantial, even intake of HAAs
that have not been used commercially for
many years. For example, a recent survey
of the U.S. diet found detectable residues
of DDT in 16% of the food samples. Human
exposure is further demonstrated by
concentrations of DDT in the adipose
(fatty) tissue. Over 95% of adipose tissue
samples taken from the U.S. population
contained detectable concentrations of
some HAA. Although the concentrations were
found to be greatest in older individuals,
even children were not immune from
exposure."[1,pg.76]
"Concentrations of HAAs and other
xenobiotics [chemicals foreign to the
body] have been measured in milk from
humans around the globe."[1,pg.82]
"In the Michigan/Maternal Infant Cohort
Study, Fein et al. (1984) evaluated the
birth size and gestational age of 242
infants and found that maternal
consumption of fish and concentrations of
PCBs in cord serum [in blood in the
umbilical cord] were correlated with
lowered birth weight, shortened gestation
[time in the womb], and smaller head
circumference. Lower weight was also
observed in children from this cohort at 4
yr [years] in a dose-dependent fashion
(Jacobson et al. 1990). Children with cord
serum PCB levels of 5.0 ng/mL [nanograms
per milliliter] or more weighed 1.8 kg [4
pounds] less on average than the lowest
exposed children. Prenatal exposure was
also associated with deficits in
neurologic development in followup studies
of these children at up to 11 yr
[years]."[1,pg.125]
"Elevated levels of the herbicide atrazine
found in municipal water supplies in Iowa
were associated with excess rates of
cardiovascular, urogenital, and
limb-reduction deficits [birth
defects]."[1,pg.130]
"Studies with laboratory animals have
shown that prenatal exposure to some HAAs,
such as methoxychlor, TCDD [dioxin], and
octylphenol and bisphenol A can reduce
sperm production."[1,pg.131]
"A neurologic assessment of an aging
population of Great Lakes fisheaters is
currently being conducted by Schantz et
al. (1996). In all, 104 fisheaters and 84
nonfisheaters, age 50 or older, were
enrolled in the study.... the fisheaters
performed more poorly on tests requiring
cognitive flexibility, word naming,
auditory recall, and more complex motor
task [sic] compared with individuals who
do not eat fish."[1,pg.173]
"Long-term epidemiologic studies of
cognitive and neurobehavioral development
have been conducted in Michigan, New York,
North Carolina, and the Netherlands on
children exposed pre- and postnatally to
PCBs from maternal consumption of
contaminated fish or other food products.
Studies of cognitive development (i.e.,
short-term memory, visual discrimination,
and IQ scores) in Michigan show consistent
correlations between prenatal exposure to
PCBs and deficits at up to 11 yr [years].
Similarly, in the Netherlands, lower
cognitive scores were associated with
prenatal exposure when tested in
3.5-yr-old children."[1,pg.174]
"Taken together, the results of animal and
human studies indicate that prenatal
exposure to PCBs can affect neurologic
development."[1,pg.175]
"It has been well documented that HAHs
[halogenated aromatic hydrocarbons] such
as TCDD [dioxin], polychlorinated
dibenzofurans (PCDFs), and PCBs, affect
immune response, and they appear to affect
all functional arms of the immune system
(innate immunity and host resistance,
cell-mediated immunity, and humoral
immunity)."[1,pg.178]
"There have only been a few studies of the
effects of HAAs [hormonally active agents]
in humans, but the results of laboratory
and wildlife studies suggest that HAAs
have the potential to affect human immune
functions."[1,pg.194]
The NRC report concludes that, at present,
the 70,000 industrial chemicals already in
use cannot be tested to see if they are
hormone-disrupters or not, because the
necessary tests do not exist.[1,pg.414]
Meanwhile between 1000 and 2000 new
chemicals are being put into commercial
use each year, inadequately tested.
Therefore, adequate knowledge of
hormone-disrupting chemicals lies many
decades in the future, a kind of
scientific holy grail. What is not known
about hormone-disrupting chemicals is
considerably larger than what is known and
will remain so for a long time to come.
Yet the NRC report has amply documented,
from studies of wildlife, laboratory
animals, and humans, that many industrial
chemicals, at levels already present in
the environment, are currently interfering
with hormones, causing problems in
reproduction and development, the nervous
system (including diminished IQ and
learning ability), and the immune system
(which protects us all from bacteria,
viruses and cancers). Harm is happening
now.
Thus hormone-disrupting chemicals meet the
two tests established by the precautionary
principle: scientific uncertainty, and a
reasonable suspicion of harm. (See REHW
#657.)
Therefore, while scientific study
continues, decision-makers have a duty to
take precautionary action to prevent
further harm even though scientific
certainty has not been established. As a
signatory to the Rio Declaration of 1992,
the U.S. is legally obligated to take
precautionary action. But of course our
government will not act spontaneously
merely to comply with the law or do the
right thing. To put it bluntly, our
government will only respond if popular
pressure is sufficient to offset inertia,
the forces of denial, and election-time
bribery from the chemical industry.
Building that pressure is up to us.
--Peter Montague(National Writers Union,
UAW Local 1981/AFL-CIO)
=====
[1] Ernst Knobil and others, HORMONALLY
ACTIVE AGENTS IN THE ENVIRONMENT
(Washington, D.C.: National Academy Press,
July 1999). ISBN 0-309-06419-8.
[2] Members of the NRC Committee on
Hormonally Active Agents in the
Environment included: Ernst Knobil
(chair), The University of Texas-Houston
Medical School, Houston, Tex.; Howard A.
Bern, University of California, Berkeley,
Cal.; Joanna Burger, Rutgers University,
Piscataway, N.J.; D. Michael Fry,
University of California, Davis, Calif.;
John P. Giesy, Michigan State University,
East Lansing, Mich.; Jack Gorski,
University of Wisconsin, Madison, Wis.;
Charles J. Grossman, Department of
Veterans Affairs Medical Center,
Cincinnati, Ohio and Xavier University,
Cincinnati, Ohio; Louis J. Guillette, Jr.,
University of Florida, Gainesville, Fla.;
Barbara S. Hulka, University of North
Carolina, Chapel Hill, N.C.; James C. Lamb
IV, Jellinek, Schwartz & Connolly,
Arlington, Va.; Leslie A. Real, Emory
University, Atlanta, Ga.; Stephen M. Safe,
Texas A&M University, College Station,
Tex.; Ana M. Soto, Tufts University,
Boston, Mass.; John J. Stegeman, Woods
Hole Oceanographic Institution, Woods
Hole, Mass.; Shanna Helen Swann,
University of Missouri, Columbia, Mo.;
Frederick S. vom Saal, University of
Missouri, Columbia, Mo.
[3] See REHW #486, #487. And see Gina
Kolata, "Study Inconclusive on Chemicals'
Effects," NEW YORK TIMES August 4, 1999,
pg. 16. For less biased coverage of the
NRC report, see J. Fialka, "More Clinical
Tests of Humans Exposed to Chemicals are
Urged in a US Study," WALL STREET JOURNAL
August 4, 1999, pg. unknown, and Marla
Cone, "Hormone Study Finds No Firm
Answers," LOS ANGELES TIMES August 4,
1999, pg. 3.
Descriptor terms: hormone disrupters;
endocrine disrupters; wildlife; fish;
birds; chemicals and health; national
research council;
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