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A study published last week confirms that children exposed to low levels of PCBs in the womb grow up with low IQs, poor reading comprehension, difficulty paying attention, and memory problems.[1] PCBs are a family of toxic industrial chemicals commercialized in 1929 by Monsanto, and now found in all humans on earth. (See REHW #327.) This latest study, published in the NEW ENGLAND JOURNAL OF MEDICINE, describes a group of children --now 11 years old --whose mothers ate PCB-contaminated fish from Lake Michigan more than once a week for several years before giving birth. The children's mental, physical, and emotional growth has been followed since birth. The mental deficits are most obvious in the 11% of the children with the most PCBs in their blood.[2]

Starting 15 years ago, Joseph and Sandra Jacobson, husband-and-wife psychologists at Wayne State University in Detroit, Michigan, looked at babies born to women who had eaten trout and salmon from Lake Michigan. Fish from polluted lakes, rivers, and coastal waters are a well-established source of PCBs and other contaminants. The Jacobsons asked several thousand new mothers about their fish-eating habits and studied the children of more than 200 of them.

The Jacobsons analyzed the PCB levels found in the blood of each baby's umbilical cord, as an indicator of PCB exposure before birth. At birth, they found, children who had higher exposures to PCBs had smaller heads and lower weights. At seven months, they tested the babies for mental function by showing them two identical photos for about 20 seconds. One of the photos was then paired with a new photo and shown to the baby again. The normal response for an infant is to spend more time looking at the new picture, indicating that it recognizes the familiar one. The babies who had the highest exposure to PCBs, however, spent as much time looking at the old photo as the new one, suggesting either deficits in short-term memory or attention problems.

When the children were four years old, they were given a battery of mental tests.[3] Again the highly exposed children showed memory impairments, this time in tests that asked them to recall progressively longer strings of words and numbers. The differences in scores between unexposed and the highest-exposed children, says Joseph Jacobson, "would be like ten points on an IQ test. We're not seeing mental retardation, but we are seeing that the children are just not doing as well."[4]

The latest study, published last week, shows that these mental deficits last at least until age 11.

These children were not living next to a toxic waste dump, and their mothers had not eaten PCB-laden fish every day during pregnancy. Their exposure to PCBs, while on the high side, is still considered to be within the range of normal background exposure levels, says Jacobson. Other possible causes, such as lead exposure or the mother's intake of tobacco or alcohol, were ruled out. (Unfortunately, maternal exposure to methyl mercury was not assessed by the Jacobsons, weakening their study.[5])

Two other studies of children have found similar problems from PCB exposures. In the Netherlands, researchers found that 18-month-old children born to women who carried relatively high but still "normal" levels of PCBs were more likely to be neurologically "nonoptimal." In fact, the higher their exposure to PCBs, the lower their neurological scores. In that study the mothers had eaten normal diets; they got their contaminants through their food and probably from water and air.[6]

In the United States, researchers at the State University of New York (SUNY) at Oswego have found that babies born to "high fish eaters"--women who in their lifetimes had eaten at least 40 pounds of fish from Lake Ontario--tested worse on several scales than did babies born to "low fish eaters" and "non-fish eaters."[7] Fish in Lake Ontario are highly contaminated with PCBs, dioxin, hexachlorobenzene, DDT and its breakdown product DDE, mirex, and other chemicals.

"We looked at the kind of stuff a pediatrician assesses in a newborn," explains Edward Lonky, a developmental psychologist at SUNY Oswego. "One of our main findings was in regard to habituation, which is a measure of neurological intactness. It's one of the tests we use to assess fetal alcohol babies, crack cocaine babies, and babies exposed to environmental contaminants. You shine a light through the eyelids of a lightly sleeping newborn and you get a startle response. When the body settles down, you repeat the light. The startle response should habituate, or diminish, over repeated administrations."[4] Normally an infant will show better habituation on the second day of testing. Lonky and his colleagues found that infants from the high-fish-eater group showed poor habituation responses as well as a greater number of abnormal reflexes and stress responses.

Such effects may not be rare. "These were not people who were eating fish every day," stresses Linda Birnbaum of the EPA (U.S. Environmental Protection Agency). "I believe the data suggest there are subtle changes going on in at least a portion of our population."[4]

The Jacobsons' latest findings have been mirrored in several animal studies,[8] and in studies of Taiwanese children accidentally exposed to high levels of PCBs.[9]

Joseph Jacobson told the NEW YORK TIMES that brain damage caused by low-level exposures to PCBs was comparable to the damage found in children exposed to low levels of lead.[10] The difference is that lead has only afflicted industrial societies; PCBs have contaminated and damaged human populations of all kinds, including the Inuit people in the Arctic and other native groups who eat fish and fish-eating mammals like seals. (And, of course, the damage from PCBs is added on top of whatever brain damage has been done by lead, mercury, pesticides, and other chlorinated hydrocarbons.[11])

It has been known for some years that children are more susceptible to damage from PCBs, and other toxics, than adults are. Some of the reasons:

** children absorb chemicals better than adults, through their skin, their gastrointestinal tract, and their lungs;

** children --especially prior to, or shortly after, birth --have poorly-developed systems for detoxifying chemicals;

** infants get much of their nutrition from one source, mother's milk, which is rich in fat, and many toxins, such as PCBs are fat soluble. (Nevertheless, breast feeding remains far more beneficial to the child than any alternative.)

** children take in more calories per pound of body weight, compared to adults;

** children have more skin contact with the outside and household environments, compared to adults, and exhibit hand-to-mouth exploratory behavior.

These factors can add up to much greater exposures for children. For example, a nursing infant typically takes in 10 times as much dioxin each day as an adult does. When this is calculated on the basis of "dioxin taken in per pound of body weight," the infant takes in 100 times as much dioxin as an adult.[12]

Between 1929 and 1989, total world production of PCBs (excluding the Soviet Union) was 3.4 billion pounds, or about 57 million pounds per year. Even after the U.S. banned PCBs in 1976, world production continued at 36 million pounds per year from 1980-1984 and 22 million pounds per year, 1984-1989. The end of PCB production is still not in sight.[13]

The whereabouts of 30 percent of all PCBs (roughly a billion pounds) remains unknown. Another 30 percent reside in landfills, in storage, or in the sediments of lakes, rivers, and estuaries. Some 30 percent to 70 percent remain in use. The characteristics of PCBs (their stability and their solubility in fat) tend to move them into the oceans as time passes. Nevertheless, it is estimated that only one percent of all PCBs have, so far, reached the oceans.[13]

Without major efforts to locate, capture, and destroy the one-to-two billion pounds of PCBs that are "out there," future generations will continue to be poisoned by PCBs, at great social (and individual) cost. We hear much of late about the good intentions of the Monsanto Corporation. Some of our friends tell us this corporation has turned over a new leaf, and is committed to behaving responsibly. If this is so, Monsanto could demonstrate its awakening by leading an effort to locate and destroy PCBs. Monsanto created (or licensed the creation of) all the PCBs in the world. This corporation could demonstrate its commitment to environmental sustainability by cleansing the planet of this brain-damaging substance, to the extent possible. An obvious first step would be to undertake a comprehensive inventory of the problem, assessing the damage done so far and cleanup-costs, as a demonstration of good faith and serious intentions.

--Peter Montague
(National Writers Union, UAW Local 1981/AFL-CIO)

[1] Joseph L. Jacobson and Sandra W. Jacobson, "Intellectual Impairment in Children Exposed to Polychlorinated Biphenyls in Utero," NEW ENGLAND JOURNAL OF MEDICINE Vol. 335 No. 11 (September 12, 1996), pgs. 783-789.

[2] Joseph L. Jacobson and Sandra W. Jacobson, "Dose-Response in Perinatal Exposure to Polychlorinated Biphenyls (PCBs): The Michigan and North Carolina Cohort Studies," TOXICOLOGY AND INDUSTRIAL HEALTH Vol. 12, Nos. 3/4 (1996), pgs. 435-445.

[3] Joseph L. Jacobson and others, "Effects of in utero exposure to polychlorinated biphenyls and related contaminants on cognitive functioning in young children," JOURNAL OF PEDIATRICS Vol. 116 (January, 1990), pgs. 38-45. And see: Joseph L. Jacobson and others, "Effects of Exposure to PCBs and Related Compounds on Growth and Activity in Children," NEUROTOXICOLOGY AND TERATOLOGY Vol. 12 (1990), pgs. 319-326.

[4] Quoted in Catherine Dold, "Hormone Hell," DISCOVER Vol. 17 No. 9 (September, 1996), pgs. 52-59.

[5] Joseph L. Jacobson and Sandra W. Jacobson, "Sources and Implications of Interstudy and Interindividual Variability in the developmental Neurotoxicty of PCBs," NEUROTOXICOLOGY AND TERATOLOGY Vol. 18 No. 3 (1996), pgs. 257-264.

[6] Abraham Brouwer and others, "Functional aspects of developmental toxicity of polyhalogenated aromatic hydrocarbons in experimental animals and human infants," EUROPEAN JOURNAL OF PHARMACOLOGY, ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY SECTION 293 (1995), pgs. 1-14.

[7] E. Lonky and others, "Neonatal Behavioral Assessment Scale performance in humans influenced by maternal consumption of environmentally contaminated Lake Ontario fish," JOURNAL OF GREAT LAKES RESEARCH Vol. 22 No. 2 (1996); in press.

[8] Per Eriksson and Anders Fredriksson, "Neonatal exposure to 2,2',5,5'-tetrachlorobiphenyl causes increased susceptibility in the cholinergic transmitter system at adult age," ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY (1996), pgs. 217-220. And: Per Eriksson and Anders Fredriksson, "Developmental neurotoxicty of four ortho-substituted polychlorinated biphenyls in the neonatal mouse," ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY (1996), pgs. 155-165. And: Edel Holene and others, "Behavioral Effects of Pre-and Postnatal Exposure to Individual Polychlorinated Biphenyl Congeners in Rats," ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY Vol. 14 No. 6 (1995), pgs. 967-976. And: Susan L. Schantz and others, "Spatial Learning Deficits in Adult Rats Exposed to ortho-Substituted PCB Congeners during Gestation and Lactation," FUNDAMENTAL AND APPLIED TOXICOLOGY Vol. 26 (1995), pgs. 117-126.

[9] Yueliang L. Guo and others, "Growth Abnormalities in the Population Exposed in Utero and Early Postnatally to Polychlorinated Biphenyls and Dibenzofurans," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103 SUPPLEMENT 6 (September 1995), pgs. 17-122.

[10] Jane E. Brody, "Study Finds Lasting Damage From Prenatal PCB Exposure," NEW YORK TIMES September 12, 1996, pg. A14.

[11] Ana Maria Evangelistia de Duffard and Ricardo Duffard, "Behavioral Toxicology, Risk Assessment, and Chlorinated Hydrocarbons," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 104 SUPPLEMENT 2 (April 1996), pgs. 353-360. And: Deborah C. Rice, "Neurotoxicty of Lead, Methylmercury, and PCBs in Relation to the Great Lakes," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103 SUPPLEMENT 9 (December 1995), pgs. 71-87.

[12] Gunilla Lindstrom and others, "Workshop on Perinatal Exposure to Dioxin-like Compounds. I. Summary," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103, SUPPLEMENT 2 (March, 1996), pgs. 135-142.

[13] Kristin Bryan Thomas and Theo Colborn, "Organochlorine Endocrine Disruptors in Human Tissue," in Theo Colborn and Coralie Clement, editors, CHEMICALLY-INDUCED ALTERATIONS IN SEXUAL AND FUNCTIONAL DEVELOPMENT: THE WILDLIFE/HUMAN CONNECTION [Advances in Modern Environmental Toxicology Vol. XXI] (Princeton, N.J.: Princeton Scientific Publishing Co., 1992), pgs. 342-343.


In RACHEL'S #511, we said, "However, most species disappear in natural aquatic ecosystems at higher pH values (more acidic conditions) than predicted by laboratory tests, thus suggesting that, in ecosystems, additional stresses enhance the effects of acidification." Obviously, this should have said "(less acidic conditions)."

Descriptor terms: pcbs; polychlorinated biphenyls; fish; central nervous system damage; great lakes; lake michigan; lake ontario; children; joseph jacobson; sandra jacobson; endocrine disrupters; lead; netherlands; oswego; edward lonky; monsanto;


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 contribution to: Environmental Research Foundation, P.O. Box 5036, Annapolis, MD 21403-7036.

--Peter Montague, Editor

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