A new study 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.
The new breast-cancer study will appear in the March/April, 1992,
ARCHIVES OF ENVIRONMENTAL HEALTH. 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
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. 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
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
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
"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
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.
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
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.
 Frank Falck, Jr., Andrew Ricci, Mary S. Wolff, James Godbold, and
Peter Dreckers, "Pesticides and Polychlorinated Biphenyl Residues in
Human Breast Lipids and Their Relation to Breast Cancer." ARCHIVES OF
ENVIRONMENTAL HEALTH Vol. 47 No. 2 (March/April, 1992), pgs. 143-146.
 Jon R. Luoma, "New Effects of Pollutants: Hormone Mayhem," NEW YORK
TIMES March 24, 1992, pgs. C1, C9.
 U.S. Environmental Protection Agency, NATIONAL STUDY TO DETERMINE
LEVELS OF CHLORINATED HYDROCARBON INSECTICIDES IN HUMAN MILK, 1975-76.
Available from National Technical Information Service [NTIS]; telephone
(703) 487-4650 and request publication no. PB284393; price: $35.00.
Thanks to Carol Van Strum of Alder-Hill Associates, Tidewater, OR for
this. Regarding PCBs, see: Allan Astrup Jensen, "Background Levels in
Humans," in Renate Kimbrough and Allan Astrup Jensen, editors,
HALOGENATED BIPHENYLS, TERPHENYLS, NAPHTHALENES, DIBENZODIOXINS, AND
RELATED PRODUCTS (NY: Elsevier Science Publishers, 1989), pgs. 345-
[380.] Thanks to Tom Webster, CBNS, Queens College, Flushing, NY, for
Descriptor terms: breast cancer; pesticides; dde; pcbs; health;
reproductive hazards; mt sinai school of medicine; hartford hospital,
hartford, ct; birth defects; sexual behavior; thyroid dysfunctions;
infertility; des; cancer; dioxin; estrogen; epa; endocrine disrupters;