Global ChangeIntersection of Nature and Culture

Every day, we are exposed to synthetic chemicals and radiation from consumer products.   If you asked me how risky these products are, my responses might range from “I don’t know” to “I don’t want to know” to “If they’re on the market, let’s hope they’re safe!”  Unfortunately, it’s difficult to know if many of the things we use every day really are safe.

Risk analysis is a four-step process by which scientists determine whether chemicals or other agents are unhealthy:

• Step 1: Hazard screening–Does a chemical look or act like other chemicals already known to be harmful or safe?
• Step 2: Exposure characterization–How much are we exposed to and how much accumulates in our bodies?
• Step 3: Effects characterization–How do different doses of an agent lead to different health effects, or what we commonly refer to as “dose-response curves”? This is usually achieved using short-term lab animal tests or epidemiological data that show things like health effects of people working at industry sites or living in contaminated neighborhoods.
• Step 4: Risk characterization–Given that we identify a chemical as being potentially dangerous (Step 1), and can measure our exposure (Step 2) and the effects that this specific exposure has on health (Step 3), what is the likelihood or risk that we will experience ill health as a result of the exposure?

As the EPA will tell you, there is often poor understanding of the long term risks of synthetic chemicals and radiation.  Much of this comes from the fact that

• We have not screened many of the chemicals on the market for potential safety.  Here’s a quote from the EPA’s website in 1996, which was subsequently removed:

For the majority of the approximately 3,000 high production volume industrial chemicals produced in the United States in 1996, we have little or no publicly available hazard screening data. These chemicals, non-polymers produced in quantities of more than one million pounds per year, are found in the workplace and in thousands of consumer products. Even fewer data are available for the remainder of the some 70,000 chemicals on the EPA’s inventory.

• Rigorous effects characterizations are hard to do.  Lab animal tests (rats, mice, etc.) are useful, but they are not a perfect substitute for understanding human health impacts.  Moreover, the kinds of long-term data we need rarely exist because that’s the nature of short grant funding cycles.  We know very little about the synergistic effects of multiple chemicals interacting in our bodies.  Finally, health problems analyzed in epidemiological studies can often be confounded with other lifestyle issues, such as weight, diet, exercise, and smoking.

Thus, we know we are exposed to these things, and we can even measure them in our bodies and in infants,  but we don’t know very well how this translates to long term health risk.

To some, this uncertainty might be license to ignore the issue.  To others, it necessitates better education about what’s in or emanating from our products so that we can decide for ourselves whether or not to limit exposure.

The Environmental Working Group has compiled several interesting lists of consumer products including specific ingredients that have the potential to be harmful:

• Shopper’s guide to pesticides in food
• Shopper’s guide to cosmetics and health care products
• Shopper’s guide to sunscreens
• Shopper’s guide to cell phone radiation

So go ahead and check out your favorite vegetable, shampoo, cell phone, or toothpaste, and see what comes up.

photo credit: http://www.flickr.com/photos/w610guy/ / CC BY-NC-ND 2.0