DDT Still Found in Teens
Even Though Banned 30 Years Ago

RANDY LEE LOFTIS / The Dallas Morning News 1feb03

Substance among CDC report's findings on U.S. chemical exposure

Despite the 30-year-old U.S. ban on DDT, the insecticide's chemical fingerprint still shows up in the bodies of American adolescents, according to the most comprehensive look yet at chemicals in the nation's people.

Mexican-Americans show three times as much DDT exposure as non-Hispanic whites or blacks. Health experts said they don't know whether the exposures came in Mexico, where DDT was made and used until recently, or through some other route.

Children showed higher levels than adults of numerous toxic substances, including nicotine byproducts, pesticides and a chemical in soft plastic toys. Health experts said the report also underscores the need to cut mercury exposure, a danger to fetal development.

The findings come from the Centers for Disease Control and Prevention's second National Report on Human Exposures to Environmental Chemicals, released Friday. The report, updating a smaller report from 2001, tracks 116 substances found in the blood and urine of about 2,500 people across the country. It is available at www.cdc.gov/exposurereport.

Animal studies have found toxicity for most of the chemicals, but only a few have so-called threshold levels to signal health risks.

A huge leap

Still, the report is considered a huge leap in understanding the chemicals that Americans get from air, water, soil, food or household items.

"This report is by far the most extensive assessment ever made of the exposure of the U.S. population to environmental chemicals," said Dr. David Fleming, the CDC's deputy director for public health science.

DDT levels have gone down, but some were still measured in people 12 to 19 years old, showing how long the chemical lasts in the environment, said Dr. Jim Pirkle of the CDC.

The higher level in Mexican-Americans is a mystery. To solve it, experts must track exposures by occupation or birthplace.

Other findings

The report also found that:

• Exposure to tobacco smoke has fallen for all age groups. Children had levels twice as high as adults, however, probably in part because of workplace smoking restrictions.
• Lead continues to show its decades-long decline, largely because of bans on leaded gasoline and lead-based paint. However, children in high-risk environments remain at risk.
• Children had higher levels of the most toxic types of phthalates, chemicals linked to reproductive problems in animal studies, than adults. Those types are found in flexible plastics, such as some toys. Adults had higher levels of phthalates used in personal care products such as shampoo.
• Children had twice the adult levels of chlorpyrifos, once a widely used pesticide. The report found similar results for more than 24 other pesticides. The samples were taken before the December 2001 federal ban on sales of chlorpyrifos for residential use.

The 116 substances measured account for just a sliver of the chemicals emitted into the environment or used in products. The CDC will add more chemicals in future updates, scheduled every two years, Dr. Pirkle said.

Spokesmen for industries that emit or use some of the chemicals said environmental advocates were overstating the report's significance.

Existing regulations already prevent human health concerns, said Jay Vroom, president of CropLife America, a pesticide and biotechnology trade group.

But Dr. Arnold Schecter, a longtime researcher into exposures to cancer-causing dioxin, said the gaps in knowledge should dictate caution.

"As a public-health physician, I prefer to err on the side of human safety," said Dr. Schecter, professor of environmental science at the Dallas branch of the University of Texas-Houston School of Public Health.

The CDC said dioxin levels in most of the people tested were too low to record a reading. Dr. Pirkle called that outcome "encouraging."

Dr. Schecter, however, said the problem apparently was the testing. "It's a travesty," he said.