Study Looks at Chemicals in Humans

Oz Hopkins Koglin / The Oregonian 27apr01

The survey may yield a better understanding of the effects of exposure to pollutants on health " We know more about the chemical contaminants in fish that swim in the Willamette River than we know about the chemicals inside our children. DR. ANDY ...

A new federal report on the potentially toxic chemicals Americans have in their bodies is the nation's first comprehensive attempt to measure environmental pollutants that affect health.

The National Report on Human Exposure to Environmental Chemicals, by the Centers for Disease Control and Prevention, measures environmental chemicals in a nationally representative sample of the population.

The ongoing survey of chemicals in human blood and urine samples is expected to provide information that scientists, physicians and health officials can use to help prevent diseases that result from exposure to certain environmental chemicals.

Dr. Andy Harris, a member of the national board of Physicians for Social Responsibility and a past president of the group, called the report a breakthrough because it demonstrates that scientific models and experts generally have underestimated the actual exposure to toxic chemicals.

"We know more about the chemical contaminants in fish that swim in the Willamette River than we know about the chemicals inside our children," said Harris, a Salem ophthalmologist. "The significance of this report is that we have been studying fish and lakes and streams -- all sorts of wildlife, and we have been flying blind in what the level of chemical contaminants is in the human body."

People exposed to an industrial spill or facing chronic exposure to a known toxic chemical probably can have their doctors run tests for the suspect substance. But about 70,000 chemicals have been introduced into the environment since World War II, so it's highly unlikely that a doctor could run adequate tests to determine the average person's exposure to a range of chemicals.

Not only would the doctor not know which chemicals to test for, but the tests also would be prohibitively expensive. For example, Harris said, running a test for dioxin, a known carcinogen, costs about $1,000.

Harris was a member of the 1998-99 Governor's Task Force for Hazardous Substance Information Reporting and Community Right to Know. The panel made recommendations that led to the state's pesticide-tracking program, which now is seeking start-up funding.

"The more we know, the more we realize that we have all got a toxic soup of chemicals in our bodies, and the CDC tries to address this," he said.

Using advanced biomonitoring techniques, Centers for Disease Control scientists measured environmental chemicals in blood and urine samples from 3,000 adults and children around the nation, rather than estimating exposure based on measurements of air, water or soil samples. The study defines an environmental chemical as a chemical compound or chemical element present in air, water, soil, dust, food or other environmental media.

The scientists assessed human exposure to 27 substances, including lead, mercury, pesticide metabolites, phthalate metabolites and cotinine (which tracks tobacco and tobacco smoke). In ongoing studies, 25 chemicals will be added to the screening each year until the testing is up to 100 toxic substances.

Over time, the measurements of environmental chemicals will be used to:

• Establish a range to determine whether a person has an unusually high level of environmental chemicals in his or her blood or urine.
• Assess the effectiveness of public health efforts to reduce the exposure of Americans to environmental chemicals such as pesticides.
• Track trends in the levels of exposure of the U.S. population to environmental chemicals.
• Determine whether levels of chemicals are higher among various groups, such as ethnic minorities, children, low-income people, the elderly and women of childbearing age.

The Centers for Disease Control report, released March 21, suggests that the average American has traces of uranium, pesticides and heavy metals but at levels less than those known to cause health problems.

The agency cautions that just because chemicals can be measured in a person's blood or urine, that does not necessarily mean the chemical can cause disease. More studies are needed to consider the duration of exposure and determine what levels of chemicals in people result in illnesses.

. Harris also wants the Centers for Disease Control exposure testing expanded to all 50 states and applied to more chemicals, along with right-to-know legislation that would inform people about their level of exposure to chemicals.

Physicians for Social Responsibility is not saying that all environmental chemicals are bad, nor is the group talking about shutting down business or industry, Harris said. "We are just looking out for human health -- your health and mine, our kids, our grandchildren -- and who can be opposed to this?"