Issue Date: January 5, 2009
Protecting Children From Toxic Chemicals
MORE AND MORE evidence exists that children are being harmed by toxic chemicals and heavy metals in the environment, yet governments and industry have done little to protect them from hazardous exposures. This is the primary message of a controversial book by veteran journalists Philip and Alice Shabecoff. In "Poisoned Profits: The Toxic Assault on Our Children," they argue that toxic chemicals and heavy metals in the environment are responsible for much of the increase in chronic disease and disability in children and explain why governments and industry have done little to stem the tide of misery.
Both authors are well qualified to present the material that appears in this book. Philip Shabecoff was the chief environmental correspondent for the New York Times for 14 of the 32 years he worked there as a reporter. Alice Shabecoff, who headed the National Consumers League, has worked as a freelance journalist on consumer topics for many years.
According to the Shabecoffs, nearly one out of three children suffers from a chronic disease or debilitating birth defect. Among the nation's 73 million children, almost 21 million suffer from one chronic disease. Cancer threatens the lives of 58,000, 6 million have asthma, 2.3 million have disfiguring birth defects, and 12 million have a developmental disorder, such as autism or attention deficit hyperactivity disorder, the book reports. The rates of all these illnesses have increased since 1950. The incidence of childhood cancer, for example, has jumped 67%, and in California, the number of children entered into the autism registry jumped 210% between 1987 and 1998.
"There is abundant evidence that the trillions of pounds of hazardous pollutants that have been poured into the environment are, in all likelihood, responsible for much of the sickness, suffering, and too often, death of America's children," the Shabecoffs write. They say this is a scandal and a crime. Perfluorooctane sulfonate in older formulations of the stain repellant Scotchgard, for example, have turned out in lab tests to be a probable cause of cancer and birth defects.
What is unusual about the book is not just that the Shabecoffs present abundant evidence that toxic substances in the environment are responsible for many health problems in children. They also carefully explain why it is difficult to establish clear cause-and-effect relationships between hazardous substances and illness. And they describe the tactics industry uses to absolve itself from blame and keep products on the market even while evidence of harm is accumulating. Dozens of industry-funded nonprofit policy organizations, such as the American Council on Science & Health, consistently defend chemicals like polychlorinated biphenyls (PCBs).
The entire book is very readable, written for the layperson, but for the average consumer, the appendices are probably the most useful sections. These illustrate how to avoid toxic exposures in the home—from phthalates and bisphenol A, for example—and advocate for a clean environment in schools and neighborhoods.
Evidence that low levels of toxic chemicals harm children comes from many sources, the book explains. First of all, it has a basis in biomonitoring. Analyses of cord blood show that every baby born today has 150 to 230 toxic chemicals in his or her blood, including PCBs, phthalates, flame retardants, bisphenol A, pesticides, lead, and mercury. This means that from the day of conception, embryos and fetuses are exposed to a cocktail of toxicants that cross the placental barrier.
For the most part, the book explains, the toxicants do not cause damage by altering DNA, the gene-bearing molecule in cells. Instead, they alter gene expression—the programming of the genes or, in other words, the times when the genes are turned on and off. This phenomenon is known as epigenetics.
THE SHABECOFFS use the analogy of a player piano to describe this process. DNA is analogous to the keys on a player piano. The set of toxic chemicals is like the sheet of punched paper that is put on the piano's roller to turn the keys on and off. If a key or gene is not turned on and off at the right times, a child may end up with autism, or a learning disability, or some other problem. For epigenetic changes, the dose of the toxicant is far less important than the timing of exposure.
A related recognition, the book explains, is that fetuses and children are far more sensitive to harmful effects of toxicants than adults. Chemicals, even at part-per-trillion levels, can affect the fetus. For example, a single small dose of an organophosphate pesticide such as chlorpyrifos (Dursban) on a critical day of development can reduce the number of brain cells, alter the architecture of the brain, and prevent normal connections among brain cells, the book notes.
Chemicals that disrupt endocrine hormones—known as endocrine disrupters—behave in this way. Even at low doses, "they can alter the way immune and endocrine systems operate," the Shabecoffs write.
Industry lawyers often argue in court that a single chemical couldn't be responsible for many different types of adverse effects, the book notes. However, the timing of exposure determines the type of damage caused. Animal studies show this clearly. For example, in rodents, different birth defects can result, depending on the day of gestation when the fetuses are exposed to a toxicant. In humans, thalidomide causes limb defects only if exposure occurs between day 20 and 24 of fetal life, and other types of defects, such as cleft palate, when exposure occurs during other periods.
The Shabecoffs stress that exposures of fetuses and children to toxicants come from both inside and outside the home. Outside sources, such as the solvent trichloroethylene (TCE) in groundwater, or butadiene in air from a nearby rubber plant, or diesel exhaust from trucks can cause problems. But equally or even more important for most children are exposures inside homes and on household lawns—phthalates in almost all perfumed personal care products, scented cleaning supplies, and flexible polyvinyl chloride; flame retardants (polybrominated diphenyl ethers) in computers, mattresses, and most upholstered furniture; bisphenol A in polycarbonate baby bottles and as a component of containers made of mixed plastics; endocrine-disrupting insecticides applied indoors and out; and 2,4-D (2,4-dichlorophenoxyacetic acid) used as a lawn weed killer.
IF A CLUSTER of illness is found in a community, it is almost impossible to prove beyond a shadow of a doubt that it came from a specific contaminant, the book explains. Files at the Centers for Disease Control & Prevention in Atlanta are filled with cluster cases for which no definitive cause has yet been determined.
Epidemiology can establish strong associations between a disease and a contaminant, but can't usually prove causation, the book notes. Animal studies showing how a contaminant causes a disease or birth defect in rodents provide another type of evidence, but do not prove causation in humans, the book explains. The new tool of toxicogenomics, which uses microarrays to study how toxicants affect gene expression, is offering hope of showing more conclusive relationships between environmental exposure and disease, but the technique needs more development.
Today, because absolute proof of causation is usually impossible to obtain, governments and industry should take a weight-of-evidence approach and apply the precautionary principle, the book says. One definition of the principle explains: When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause-and-effect relationships are not fully established scientifically.
In some situations where there are clusters of illnesses, the companies responsible for the pollution settle with the victims' families, but without admitting harm, the book says. Under settlement agreements, the families are not allowed to discuss the terms. So the harm caused by the chemical receives little publicity.
The high rate of cleft palate near Dickson City, Tenn.—18 cases over three years, when only two might have been expected—is one example of a cluster. The Shabecoffs use this case to show how difficult it is to prove causation and to obtain compensation for probable injury. From the late 1960s until 1988, the Scovill-Schrader plant dumped TCE in a landfill near Dickson City. High levels of TCE were periodically found in the groundwater and wells in the area. There is limited, but not conclusive, evidence that fetal exposure to TCE can cause cleft palate. The Scovill company went bankrupt and was sold to a successor. The affected families sued the successor and won a settlement. But the successor has also filed for bankruptcy, and even though the case has been settled, the affected families could end up with no money.
ALTHOUGH THERE IS more and more evidence that low-level toxic exposures harm fetuses and young children, it is still extremely difficult to persuade or force companies and governments to phase out or ban harmful substances, the book notes. One reason is that companies spend a great deal of money on lobbyists who strive to prevent stricter laws from being passed. Petrochemical corporations give hundreds of millions of dollars to politicians at all levels of government, much of it through trade associations.
A second reason is the Daubert v. Merrill Dow Pharmaceuticals Supreme Court decision of 1993, which gives judges more leeway than they had previously to keep "unscientific" evidence out of the courtroom. "Daubert requires the judge to examine the underlying research that the plaintiffs and defense propose to present and admit only evidence he or she deems scientifically reliable," the book says. Sometimes if an expert witness wants to present evidence that a chemical caused a variety of harmful effects, the judge decides—under the false assumption that a single toxicant cannot cause more than one health effect—that the testimony is scientifically unsound and disallows it.
It is a "crime" that companies don't work harder to test products before they go on the market and remove them from commerce when the weight of evidence indicates a problem, the Shabecoffs contend. But until laws are changed and courtroom practices are changed, what parents and prospective parents can do is try to keep toxic materials out of their homes and food and cooperate to keep them out of schools and playgrounds, the book says.
The Shabecoff's sound, well-researched book presents an almost overwhelming amount of evidence of harm from environmental chemicals. In addition, it shows how difficult it is to translate knowledge of harm into prevention. Furthermore, it argues effectively that the public and private institutions that are supposed to be looking out for the welfare of children are failing to protect them.
The Shabecoffs conclude that whatever our political or religious orientation, "if we love our children, we should want to protect them, to give them a safe, healthy environment in which to be born and to grow up."
Bette Hileman is a retired C&EN senior editor who writes extensively on issues of chemicals and the environment.
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