=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #279
—April 1, 1992—
News and resources for environmental justice.
——
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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NEW STUDY LINKS BREAST CANCER TO
DDT, PCBS AND OTHER CHLORINATED CHEMICALS
A new study[1] of women with breast cancer reveals that their
breast tissues contain elevated levels of DDT, DDE and PCBs,
compared to breast tissues of women with non-cancerous breast
disease. DDT is a well-known, persistent pesticide banned in
1972; DDE is a byproduct of the natural breakdown of DDT in the
environment; PCBs are persistent industrial toxins banned in 1976.
“This is a very important study,” said Dr. Richard Clapp of the
JSI Center for Environmental Health Studies in Boston, and former
director of the Massachusetts Cancer Registry. “We should all pay
close attention to this one,” he said.
Although the number of women involved is small, the new study
adds to a growing body of evidence indicating that many
chlorinated hydrocarbons mimic female hormones and disrupt the
human reproductive system and immune system. PCBs, DDT, and DDE
are all chlorinated hydrocarbons, and all have been found to
mimic female hormones in recent studies of wildlife and of
laboratory animals.[2]
The new breast-cancer study will appear in the March/April, 1992,
ARCHIVES OF ENVIRONMENTAL HEALTH.[1] A team of researchers from
University of Michigan, Mt. Sinai School of Medicine (New York),
and Hartford Hospital in Hartford, Connecticut, led by Dr. Frank
Falck, Jr., conducted the study of 40 women who had been examined
at Hartford Hospital between May and September, 1987 for palpable
breast mass or mammographic abnormality. Tissue biopsies had been
done for diagnostic purposes and this study looked at chemical
contaminants in the tissue samples. Half the women had been
diagnosed with breast cancer and half had been diagnosed with
non-cancerous breast disease (mostly benign cysts).
The two groups of women were comparable in age (average of 63
among the cancer cases, and 59 among the non-cancer control
group). There were appreciably more smokers among the non-cancer
controls (15 out of 20) than among the cancer group (6 out of
20). Average height and weight were nearly identical for the two
groups.
The average (mean) concentration of PCBs, DDT, and DDE were 50%
to 60% higher in the women with cancer. Concentrations in the
fatty tissues of the cancer cases were: DDT 216 ppb [parts per
billion], DDE 2200 ppb, PCBs 1965 ppb.
The causes of breast cancer are not well understood. Known risk
factors include age at which menstruation begins (later is
safer), and onset of menopause (earlier is safer). Both these
factors suggest that female hormones may be involved in this
particular cancer. Nevertheless, when all the know risk factors
for breast cancer are taken into account, they explain less than
half the 179,500 cases that occur each year among U.S. women.
Therefore, researchers are looking for evidence that perhaps
chemicals in the environment, mimicking hormones, may cause
breast cancer in humans, as well as causing other disturbances of
the reproductive and immune systems.
Two weeks ago, scientists concerned about chlorinated
hydrocarbons in the environment held a symposium in Washington,
DC, to share information on the hormone-like qualities of DDT,
DDE, PCBs, dioxins, furans and others.[2] Scientists at the
symposium, which was initiated by Dr. Theo Colborn of the World
Wildlife Fund, examined the growing body of knowledge about
environmental chemicals that mimic female hormones.
The symposium emphasized disruptive effects of these chemicals on
fetuses. SCIENCE TIMES (a section of each Tuesday’s NEW YORK
TIMES) reported some of the findings from the symposium this way:
THE EFFECTS OF THE CHLORINATED ORGANIC CHEMICALS ARE MOST
SIGNIFICANT IN FETUSES. THEY INCLUDE PARTIAL RETENTION OF SEX
GLANDS OF THE OPPOSITE GENDER, PROFOUND CHANGES IN SEXUAL
BEHAVIOR, AND REDUCED FERTILITY. IN SOME STUDIES, LABORATORY
RODENTS EXPOSED AS FETUSES TO EVEN SMALL DOSES OF PCBS AND
DIOXINS WERE BORN AS ‘FEMINIZED’ MALES OR ‘MASCULINIZED’
FEMALES….
STUDIES WITH RATS, MICE AND SEA GULLS HAVE SHOWN THAT FETUSES
EXPOSED TO VARIOUS ENVIRONMENTAL HORMONE MIMICS FAIL TO DEVELOP
NORMAL SEX ORGANS, OR EVEN DEVELOP PARTLY FORMED DOUBLE SETS OF
SEX ORGANS.
DR. [MICHAEL] FRY [A WILDLIFE RESEARCH PHYSIOLOGIST AT UNIVERSITY
OF CALIFORNIA, DAVIS] REPORTED THAT UNUSUAL SEXUAL BEHAVIORS HAVE
BEEN OBSERVED AMONG GULLS IN THE WILD IN CONTAMINATED REGIONS
LIKE THE SEAS OFF SOUTHERN CALIFORNIA AND THE ISLANDS IN THE
GREAT LAKES. MALE GULLS IGNORED BREEDING COLONIES, AND PAIRS OF
FEMALE GULLS TRIED TO NEST TOGETHER, AS IF ONE WERE MALE. THERE
APPEARED TO BE A CORRELATION BETWEEN THE AMOUNTS OF POLLUTANT
CHEMICALS IN THEIR BODIES AND THE DEGREE OF UNUSUAL SEXUAL
BEHAVIOR….
A SECOND STUDY [BY DR. DICK PETERSON OF THE UNIVERSITY OF
WISCONSIN SCHOOL OF PHARMACY], IN WHICH MOTHER RATS RECEIVED FROM
0.064 MICROGRAM TO 1 MICROGRAM PER KILOGRAM OF BODY WEIGHT OF
TCDD [DIOXIN], SHOWED THERE WERE STRIKING ALTERATIONS IN
SEX-LINKED BEHAVIOR AMONG THE MALE OFFSPRING AT MATURATION. THE
MALES SHOWED A MARKED RELUCTANCE TO MOUNT A SEXUALLY RECEPTIVE
FEMALE COMPARED WITH A CONTROL GROUP OF MALES THAT HAD NOT BEEN
EXPOSED TO TCDD IN UTERO [BEFORE BIRTH]. THEY ALSO PRODUCED HALF
THE USUAL AMOUNT OF SPERM AND TOOK TWICE AS LONG TO EJACULATE.
“WE FOUND THAT PERINATAL [NEAR THE TIME OF BIRTH] TCDD EXPOSURE
ALTERS SEXUALLY DIMORPHIC RESPONSES THAT AFFECT THE BRAIN,” DR.
PETERSON SAID. “IT DECREASES THE EXPRESSION OF MASCULINE SEXUAL
BEHAVIOR. AND IT INCREASES THE EXPRESSION OF FEMININE SEXUAL
BEHAVIOR.” HE SAID THE EFFECTS ON BRAIN FUNCTION THAT APPARENTLY
OCCURRED WHEN THE RATS WERE FETUSES AND NEWBORNS WERE PROBABLY
PERMANENT AND IRREVERSIBLE….
HORMONE-LIKE CONTAMINANTS IN THE ENVIRONMENT MAY PRODUCE SEVERAL
OTHER SORTS OF DAMAGE, RESEARCHERS SUGGESTED, INCLUDING
SUPPRESSION OF THE IMMUNE SYSTEM, THYROID DYSFUNCTION, DECREASED
FERTILITY, AND BIRTH DEFECTS.
It would be unthinkable to experiment on humans to see if they
suffer from similar aberrations after exposure to dioxin or other
hormone-mimicking chemicals while in the womb or shortly after
birth. Nevertheless, the symposium was told, the now-banned drug
diethylstilbestrol (DES) may have served as a human experiment of
sorts. The drug, once prescribed to millions of women, mimics
natural sex hormones just as chlorinated organics are now thought
to do.
Both sons and daughters of DES-treated women have suffered from
malformed reproductive systems, infertility, and rare cancers.
The sons and daughters were exposed to DES in the womb, but the
consequences did not become clear until they matured.
Dr. John McLachlen, director of the Laboratory of Reproductive
and Developmental Toxicology at the National Institute of
Environmental Health Sciences said, at this point researchers are
sure of only three points: that certain chemicals act like
estrogens [female hormones] in the environment; that in
experimental animals you can perturb the reproductive system with
these chemicals; and that you see some of the same effects in
humans exposed to DES.
One other thing seems certain: American women have been exposed
to chlorinated hydrocarbons for decades and they carry these
chemicals in their breast tissues and milk.
A study by EPA (U.S. Environmental Protection Agency) of
Americans in 1975-76 revealed that 99% of American women had
detectable levels of DDT and DDE in their breast milk. The
average concentration of DDT in the lipid (fat) portions of the
milk had 553 ppb (parts per billion); the average DDE
concentration was 3521 ppb. Other chlorinated hydrocarbons, such
as PCBs, are present in breast milk as well.[3] Chlorinated
hydrocarbons are more soluble in lipids than in water, so they
tend to concentrate in body fat and milk fat. In women, lactation
is the principle route by which such chemicals are excreted from
the body.
Many scientists emphasize that the benefits of breast-feeding
still outweigh the adverse consequences. Because breast-fed
babies receive immunity to disease with their mother’s milk,
breast-fed babies have fewer infections than those who are
bottle-fed, studies show. The important lesson from this
information is not to discourage breast feeding, but to phase out
or ban chlorinated hydrocarbons.
–Peter Montague, Ph.D.
Descriptor terms: breast cancer; pesticides; dde; pcbs; health;
reproductive hazards; mt sinai school of medicine; hartford
hospital in hartford; birth defects; sexual behavior; thyroid
dysfunctions; infertility; des; cancer; dioxin; estrogen; epa;