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July 22, 2005,
8:19 a.m.
A Chemical Reaction
Reading new CDC news.
The Centers for Disease Control (CDC) has released its biannual report on the results of its National Biomonitoring Program, which measures the levels of some 148 chemicals in blood and urine taken from a large cross-section of the U.S. population. CDC director Dr. Julie Gerberding expressed the hope that the report might help us understand "the connection between toxic chemicals and potential human health effects."
Various celebrities (notably PBS's Bill Moyers) have submitted to biomonitoring tests in recent years and have reported that their bodies were "contaminated" with "carcinogens" and "toxins." Now, as a result, concerned citizens clamor for their own tests, often assuming that manmade chemicals are particularly dangerous ones and hoping to be found "chemical-free."
But the presence of those chemicals — people's "body burden" — does not necessarily have any implications for health. Some perspective is in order:
All living matter is comprised of chemicals. All of our food is chemicals — even the so-called "natural" and "organic" foods. The human body is made up of oxygen, carbon, hydrogen, nitrogen, calcium, sodium, copper, zinc, iron, cobalt, and trace levels of "toxins" such as arsenic and bromine. The story is similar for our food, which naturally contains substances such as the arsenic in potatoes and the cyanide in lima beans.
Due to the intimate relationship we have with our environment, we are exposed to thousands of these natural and man-made chemicals every day. These exposures result not only from food, air, water, and products like paint, cosmetics, pesticides, drugs, plastics, and household cleaners, but also from natural sources, including minerals leaching into ground water from soil and dioxins from forest fires or volcanic eruptions.
Scientists are now able to measure exceedingly low concentrations of chemicals in human tissues. It has become possible for scientists to measure parts per quadrillion (ppq) of some chemicals found in humans. To visualize this fraction, imagine one inch out of a trip from Earth to somewhere about 170 times as far away as the sun (that is, about 16 billion miles away).
The mere ability to detect a chemical in the body is only an indication that exposure has occurred. It does not mean that there is a health hazard, nor does the measurement tell us what the source of exposure was.
Biomonitoring of human samples has proven useful in protecting workers from high-dose exposure to truly dangerous chemicals by determining who had the highest exposure and taking remedial action. And monitoring of blood samples from children, particularly thirty years ago, helped us identify which segments of the population had dangerously high levels of lead.
But the new CDC data on trace chemicals found in blood and urine — including, as Dr. Gerberding proudly said in her press conference, some "38 never before measured" — are not useful in the same way because there is no evidence that these very low levels pose any harm. Unfortunately, the CDC report will inevitably trigger endless mischief, as environmental activists use it to claim that we are all "polluted," headed for an early grave because industrial chemicals have invaded our bodies and left us at risk for disease.
Using government biomonitoring data to terrify Americans about trace environmental exposure to chemicals will do absolutely nothing to promote public health. It will only serve to distract us from very real everyday risks around us, while undermining our confidence in the technologies that afford us the highest standard of living in the world. So a word to the wise: take the CDC report with a hefty grain of sodium chloride.
— Dr. Elizabeth Whelan is president of the American Council on Science and Health, which has published a new report on biomonitoring.
