Study of Toxins Says U.S. Children Are at High Risk

From compounds in plastics and cosmetics to pesticides banned decades ago, Americans are carrying an array of toxic chemicals in their bodies, with children bearing the brunt of the exposure, according to a report released Friday by the federal Centers for Disease Control and Prevention.

The bodies of American children contain higher levels of about a dozen industrial chemicals and pesticides than their adult counterparts, the report shows.

Even though the effects of most of the chemicals are largely unknown, health experts say the new findings are troubling because young children, infants and fetuses are especially susceptible to the dangers posed by environmental chemicals.

Thousands of adults and children were tested for 116 chemicals in 1999 and 2000 as part of a broad national survey of American health.

For the vast majority of the chemicals, such testing had never been conducted in the U.S., and it is the first time that exposure by age, race and sex has been analyzed on a national scale. For each chemical, the blood and urine of about 2,500 people were tested.

“This report is by far the most extensive assessment ever made of the exposure in the U.S. population to environmental chemicals,” said Dr. David Fleming, deputy director of the CDC.

The chemicals were measured in trace amounts, parts per billion or smaller, the equivalent of less than a drop in a human body.

Researchers suspect exposure to tiny amounts of some environmental chemicals in the womb or early childhood may permanently alter a child’s intelligence, motor skills, memory, behavior, fertility and immune response.

“Kids are being exposed. We don’t have all the details yet about health effects, but it can’t be good for kids,” said Dr. Howard Frumkin, chair of environmental and occupational health at Emory University in Atlanta and director of its pediatric environmental health center. “This report is a wake-up call that we should be looking seriously at alternatives for pest control.”

The analysis reveals “a mixed picture,” said James Pirkle, assistant director for science at the CDC’s National Center for Environmental Health. There were “some encouraging findings and some of concern,” he said.

Compared with adults, children’s bodies contain more organophosphate pesticides, which have been linked to effects on developing brains in some tests. Levels of the pesticide chlorpyrifos (known as Dursban) were twice as high in children than in adults. The chemical, used in bug bombs and lawn and garden sprays, was the most widely used insecticide in the United States until its household use was banned by the Environmental Protection Agency a year ago, largely because of the risk to children. Other organophosphate pest-killers remain in widespread use.

Also, a phthalate compound used in vinyl and other soft plastic was higher in children and adolescents than in adults. One theory is that young children often chew on toys and other plastics. Another phthalate compound, found in soaps, shampoos, perfumes and other consumer products, is higher in adults.

Children also carry more substances called polycyclic aromatic hydrocarbons, found in vehicle exhaust and other sources of combustion, as well as six heavy metals, including lead, cobalt and barium, the CDC said. Exposure to secondhand smoke is also more than twice as high in children as adults.

Young people wind up with a bigger dose of contaminants in their bodies partly because of their slower metabolism. And, pound-per-pound of weight, they consume larger proportions of food, air and water. They also tend to play on floors, dig in dirt and put things in their mouths.

“Children literally eat, drink and breathe three times an adult does on a weight basis,” said Dr. Richard Jackson, director of the CDC’s environmental health center. “They absorb more from the environment than an adult.”

The developing bodies of fetuses, infants and toddlers are particularly vulnerable to the effects of environmental contaminants. Industrial chemicals and pesticides can build up in a pregnant woman, then pass to the fetus just as its brain, reproductive organs and immune system are growing. For most of the chemicals, however, no one knows what level in the human body may trigger effects.

Some medical experts suspect that environmental contaminants could be behind some neurological disorders, such as attention deficit disorder and Parkinson’s disease and hormone-related disorders, such as endometriosis, breast cancer, testicular cancer and infertility.

Environmental groups and health advocates Friday urged government agencies to strengthen regulation of the compounds, many of which are in common use by industries and pesticide companies.

“It’s time for our government to do more to crack down on these toxic pollutants in our air, water and food,” said Robert Musil, executive director of Physicians for Social Responsibility.

But industries that use and manufacture the chemicals say that they already face tough federal standards and tests and that health effects are mostly unproven. Jay Vroom, president of CropLife America, a group representing the pesticide industry, said the insecticide with the highest exposure for children, Dursban, is already gone from households, and that companies are now required to look deeper for possible health effects.

“We have agreed as an industry ... to accept a whole new battery of testing for pesticides, looking at exposures to children in particular,” Vroom said.

Most of the chemicals included in the report disrupt hormones in animal tests, some by mimicking estrogen or blocking testosterone, others by attacking brain development, the immune system or the thyroid.

But such effects can be subtle and difficult to detect in people. Scientists are convinced that wild animals are suffering from suppressed immune systems and feminization from chemicals acting like hormones. For humans, there is compelling evidence that mercury, lead, tobacco smoke and compounds called PCBs are causing harm. But little is known about most others in the report, such as phthalates, organophosphate pesticides and atrazine, the country’s most widely used herbicide.

The study found that people still are carrying traces of dangerous and persistent chemicals banned in the United States 25 to 30 years ago. The major byproduct of the pesticide DDT was found in 98% of the people sampled, and even Americans who are younger than 19 -- born years after the manufacture and use of DDT ended in 1972 -- have “clearly measurable” levels of the pesticide in their bodies.

Mexican Americans are carrying three times more DDT residue than non-Latino whites or blacks, the study found. The higher exposure may reflect recent use of the pesticide in Mexico, or it may be that farm workers in the United States, mostly Mexican Americans, are being exposed to decades-old DDT that remains in soil. DDT is believed to cause cancer.

The results were more encouraging for PCBs, polychlorinated biphenyls, which have been shown to suppress immune systems and alter brain development. Most PCBs and dioxins were not detectable in the majority. Use of PCBs was banned 25 years ago in the United States, but they remain in the environment.

The findings about lead exposure were also welcomed as good news. The percentage of children suffering from elevated lead levels dropped by half since the early 1990s to 2.2%, according to the report. The main reason is removal of lead-based paint.

Americans also are breathing considerably less cigarette smoke than they were a decade ago. Nevertheless, more than half of American children, 58%, are still exposed to secondhand smoke, the report says. Children and adolescents have more than twice the levels of a nicotine byproduct, cotinine, than adults, and blacks have more than twice as much as non-Latino whites or Mexican Americans.