This column appeared in the New York Post.
In any word-association game today, the term "chemicals" prompts responses like "harmful," "disease," and "risk." That's why a new report from the Centers for Disease Control -- expected in the next three weeks -- will definitely need to be taken with a large grain of, well, sodium chloride.
Every two years, the CDC's National Biomonitoring Program releases data on the presence of some 300 chemicals in specimens of blood and urine taken from a large cross-section of the U.S. population. The researchers take particular interest in measuring body levels of chemicals from man-made sources, including those in food, consumer products and the general environment.
The concentration of any given chemical in human tissue is often referred to as the "body burden" of that substance. Various celebrities (notably PBS's Bill Moyers) have grabbed publicity in recent years by submitting to tests and reporting that their bodies were "contaminated" with "carcinogens" and "toxins" -- everything from PCBs to dioxin to DDT. Some concerned citizens are now demanding their own blood tests to confirm that they are "chemical-free" -- and thus, they assume, healthy.
Since the upcoming CDC study will inevitably confirm the presence of "chemicals" in the samples, some perspective is in order:
All living matter is comprised of chemicals.
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 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.
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 blood levels of lead.
But the coming CDC data on myriad trace chemicals found in blood and urine are not useful in the same way because there is no evidence that these very low exposures pose any harm. Yet the report will still trigger endless mischief, as environmental activists claim that we are all "polluted" and 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.