Chemical’s Use Extensive: 93% of People Showed Exposure in CDC Study

By Susanne Rust, Milwaukee Journal Sentinel

Nov. 9–Government researchers have confirmed widespread exposure to a common chemical plasticizer, linked to a variety of ailments, that is found in items such as baby bottles and dental sealants.

Nearly 93% of more than 2,500 people tested by the Centers for Disease Control and Prevention had bisphenol-A in their urine.

In more than 250 experiments conducted on lab animals, bisphenol-A has produced genetic changes that lead to reduced sperm counts, infertility, testicular cancer, attention deficit disorder and reproductive abnormalities.

Work also has been done on human tissue, with results showing that exposure to bisphenol-A can may cause changes in prostate and breast tissue.

The chemical, which is also found in wine, DVDs and the linings of food cans, is produced in massive volumes — nearly 6 billion pounds a year. It has been a point of controversy for the past several years. Although many academic and government scientists believe the chemical behaves like a hormone and can disrupt the endocrine system at levels that people are routinely exposed to, others contend that the chemical is safe at these levels.

This summer, a panel appointed by the National Institute of Environmental Health Sciences minimized concerns about the chemical but concluded that there was some concern in terms of its effect on the neural development of fetuses and children.

In this latest survey, which appeared online in the journal Environmental Health Perspectives, the CDC examined concentrations of bisphenol-A and another compound, called 4-tertiary-octylphenol, in 2,517 Americans ages 6 to 85. Exposure to the second compound can come from detergents, water, personal care products and food. It was discovered in about 57% of those tested.

Study includes children

The CDC team, led by chemist Antonia Calafat, used samples taken from the 2003-’04 National Health and Nutrition Examination Survey, a population survey the CDC established in 1999. The survey is designed to measure the health and nutritional status of Americans who are at least 2 months old.

“We were interested in assessing exposure to environmental chemicals,” Calafat said.

Although her team reported similar results for bisphenol-A in 2005, those findings were based on a smaller subset of people and were not representative of the U.S. population. That study did not include information on children.

The researchers found that children ages 6 to 11 had higher concentrations of bisphenol-A than adolescents, who in turn had higher amounts than adults.

Calafat could not say why children had higher levels of bisphenol-A than either adolescents or grown-ups, but she speculated that it might have to do with behavior — eating more packaged foods or coming into contact more with some of these items — or the way children metabolize these kinds of chemicals.

“Children appear to have higher concentrations for many nonpersistent chemicals such as phthalates and pesticide metabolites,” she said. Nonpersistent chemicals are compounds that don’t collect in fat and tissue. They are generally excreted from the body within hours of exposure.

“We don’t know why this is. Maybe they are eating more and breathing more air in terms of their body weight when compared to adults. But it points to a need for additional research,” she said, adding that researchers should focus their attention on ways the chemicals could get into children and should target and evaluate potential health effects.

Varying levels

The study also found that women had higher levels than men, and Mexican-Americans had significantly lower levels of bisphenol-A than non-Hispanic whites and blacks. There also were significant differences among income groups: Those with lower incomes had higher concentrations than people with higher incomes.

Time of day made a difference, too. The team found that samples taken in the afternoon were significantly lower than morning and evening samples.

The team found concentrations ranging from 0.4 micrograms per liter to 149 micrograms per liter, with a mean of 2.6 micrograms per liter. The mean concentration was nearly two times as high as in the previous CDC study. However, Calafat said the two could not be compared because the first study did not include children.

What these numbers mean is debatable.

Steven G. Hentges, executive director of the American Chemistry Council’s Polycarbonate/BPA Global Group, said the study affirmed his trade group’s position that levels of bisphenol-A are low in people and therefore not concerning.

“This CDC report confirms that people are exposed at levels far below what could be considered harmful,” he said.

But Ana Soto, a professor at the Tufts University School of Medicine who has studied bisphenol-A for more than a decade, said: “This looks like we are being exposed to levels that are problematic. I think we’re at a point where we have enough data to develop public health policies to prevent harm.”

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