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#665 - Cause for Precautionary Action, 25-Aug-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

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

"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

"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

"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

"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

"Concentrations of HAAs and other xenobiotics [chemicals foreign
to the body] have been measured in milk from humans around the

"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

"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

"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

"Taken together, the results of animal and human studies
indicate that prenatal exposure to PCBs can affect neurologic

"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

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