About Bio-monitoring

Every single day, we're exposed to hundreds of chemicals in our air, our water, our food, and our soil not to mention our toiletries, cleaning supplies, and gas tanks.

Although many people find the idea of being exposed to chemicals frightening, not every chemical is toxic. In fact, most chemicals are harmless in small quantities and only cause serious disease as their concentrations rise. Others won’t make us sick even when we're exposed to relatively large amounts of them.

The health effects of some chemicals—like formaldehyde and benzene—are fairly well understood; for most, however, the answers simply aren’t there. To evaluate the burden of chemicals in the body, we need to first know who has been exposed and at what level.

The Center for Disease Control and Prevention's Environmental Health Laboratory is trying to determine that. Using a technique called biomonitoring, scientists are attempting to find out how much of which chemicals are getting into people's bodies.

Biomonitoring allows scientists to assess a person's level of chemical exposure by directly measuring levels in their body using human tissues and fluids like blood and urine. These measurements reflect the amount of the chemical that a body may retain from all environmental sources such as food, water, soil, air and dust. The amount of the chemical in the body often provides scientists with the best exposure information when evaluating the potential for health impacts.

But just because a chemical is found in a person's tissue, blood or urine, doesn't mean that it's going to harm them. It simply shows that they've been exposed to it. Although additional research studies are required to determine what levels of exposure are safe, biomonitoring provides an important first step towards better understanding the impact of chemicals on our health.

The Environmental Health Laboratory's National Biomonitoring Program currently tracks more than 300 environmental chemicals. Their findings were published in 2009 in the Fourth National Report on Human Exposure to Environmental Chemicals.

Contact Us

Monday - Friday
8:00am - 5:00pm

Tel: (626) 430-9820
Email: tox@ph.lacounty.gov

County of Los Angeles Public Health
Environmental Health
Toxicology & Environmental Assessment Branch