For decades, federal and state agencies have been testing the air, water and soil for pollution, but there has been relatively little effort to determine the extent of toxic substances in the bodies of Americans.
On Wednesday, the federal Centers for Disease Control and Prevention will take a major step toward answering the question: How polluted are people?
In a first-of-its-kind survey, the centers tested blood and urine samples given by 5,000 Americans in 1999 for 28 toxic substances: 14 heavy metals, including lead, mercury, cadmium, beryllium and uranium; six kinds of metabolites, which reveal exposure to 28 pesticides; seven kinds of phthalates, which are used in the manufacture of plastics and other consumer products, and cotinine, a byproduct of secondhand tobacco smoke.
Since the petrochemical industry started around World War II, 85,000 new chemicals have been manufactured and released into the environment and another 1,500 chemicals are introduced each year.
Of the 15,000 chemicals in common use today, the vast majority have not been tested individually for human health impacts and virtually none has been tested to discover what impacts may occur in combination with other chemicals, according to the Institute for Children's Environmental Health in Langley, Wash.
Many public health experts believe there is a relationship between man-made chemicals in the environment and increased instances in recent years of asthma, Parkinson's disease, reproductive disorders, low sperm counts, genital defects in male infants, breast cancer, childhood leukemia, brain tumors, attention deficit disorder, autism, dyslexia and other chronic diseases.
However, there is not enough data available to permit the kind of research that would prove or disprove a direct connection. Except for a handful of toxic substances like lead, there has been virtually no widespread testing for contamination in people.
"I can tell you so much more about the health of a striped bass swimming upriver than I can about the health of a child in New York City," said Shelley Hearne, an environmental scientist and executive director of Trust for America's Health in Baltimore, which advocates the establishment of a national health information network that would gather information on the occurrence of chronic diseases and levels of exposure to toxic substances.
The 28 substances in the CDC survey are "just the tip of the iceberg," Hearne said. Scientists believe it likely that the majority of Americans have traces of as many as 500 toxic substances in their bodies, Hearne said.
Future surveys will eventually be expanded to include as many as 100 toxic substances, the centers said in a briefing paper.
"What the CDC is doing right now is not rocket science," Hearne said. "They could be testing for hundreds of substances in our bodies, but we have never made the investment as a country in having this very easy technology."
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