We're all familiar with the saying "You are what you eat." But according to research conducted by a nonprofit research group, you might also be the toxins your mother ate, breathed, and absorbed from the world around her. As part of what it calls the Human Toxome Project (yes, toxome is a made-up word referencing the Human Genome Project), the Environmental Working Group (EWG) has examined human tissue samples for the presence of chemicals, including a test of 10 newborns; they checked for 413 chemicals in umbilical-cord blood and detected an average of 200 in each sample.

Ugh. Are environmental toxins now a form of original eco-sin? You inherit the toxic transgressions of an ecologically "fallen" society? It's enough to make even the non-Catholics among us cringe with guilt. But EWG isn't aiming to induce panic (or get you to confession); rather, it hopes to inform. The intention of the project, called biomonitoring, is to map out the vast array of chemicals we're exposed to on a daily basis.

The group screens blood and urine samples for, among other substances, heavy metals (lead, mercury); pesticides (even ones that have been banned for many years); bisphenol A, a toxin found in food-can linings; and phthalates, a family of chemicals used to make plastic flexible. The project is ongoing, and since its inception EWG has tested about 100 people from myriad regions and demographic groups.

While 100 people do not make up a statistically significant sample of the U.S. population, senior EWG scientist Anila Jacob explains that the results are still important: "These 100 people come from a variety of backgrounds, a variety of geographical areas, and we're finding similar profiles in the people we test. So this tells us exposure is pretty widespread."

The Centers for Disease Control and Prevention (CDC) perform a similar study on larger groups-the number of people tested depends on the chemical-that are representative of the U.S. population. The study, called the National Report on Human Exposure to Environmental Chemicals, comes out every few years (the next one is due in 2008, but results for certain chemicals are available on the CDC website now), and the last report included 148 chemicals-that's 121 more than the 26 chemicals the report covered when it first came out in 2001.

It's tempting to draw conclusions-the number of environmental chemicals has apparently increased, and so have the number of cases of health issues such as autism, cancer, and ADHD. But Larry Needham, a supervisory research chemist at the CDC, cautions against knee-jerk thinking. Some of the increase is likely due to an increased ability to detect these chemicals. And, of course, as any scientist will tell you, causation is hard to prove. "What epidemiological studies show are associations, not causation, in general," he says, adding that while he doesn't know of any good scientific data linking environmental chemicals to autism, many studies are under way now.

Michael Kamrin, a professor emeritus at Michigan State University's Center for Integrative Toxicology, notes, "If you read the newspapers, what you'll often find is that there is some association that's talked about on the basis of one study, and then someone else does another study, and they don't find it. Often it's hard to replicate these studies and to really show what you thought might be cause-and-effect is actually cause-and-effect."

In addition, mere exposure to chemicals is not the only factor to consider when thinking about your body's reaction to a toxin. According to the CDC, the dose and concentration of the chemicals matter, as does individual susceptibility to them. We've all heard of nonsmokers who get lung cancer, and of lifelong smokers who don't. In these cases, genetic susceptibility is involved.

Related Resources

Related Articles Environmental Considerations with Food How To Make Your Weekly Grocery Shop a Green One Going Green for Meals See All Related Articles

Related Eco Categories Science & Technology Transportation & Travel How to Guides Top 10s

Topics Saving Money Food Family Home Recycling

Tip of the Day Plant Some Fresh Air Go with the (Low) Flow See All Tips

Glossary Triple bottom line Ecosystem Old-growth tree Latex Perfluorochemicals (PFCs) Full Glossary

Site Resources Directory Answers Quizzes