At a glance
- The National Exposure Report does not determine whether levels of environmental chemicals are safe or associated with adverse health effects.
- Separate research studies are needed to assess health risks.
- Blood, serum, and urine levels reflect overall exposure from various sources but do not indicate specific exposure sources or routes.
Important considerations
Research studies, separate from CDC's National Report on Human Exposure to Environmental Chemicals (Report), are required to determine whether blood or urine levels are safe or are associated with disease or adverse effects.
The measurement of an environmental chemical in a person's blood or urine does not mean, by itself, that the chemical causes disease. Advances in analytical methods allow us to measure low levels of environmental chemicals in people, but separate studies of varying exposure levels and health effects are needed to determine whether blood or urine levels result in disease. These studies must also consider other factors such as duration of exposure. The Report does not present new data on health risks from different exposures.
For some environmental chemicals, such as lead, studies have given us a good understanding of the health risks associated with different blood levels. However, for many environmental chemicals, we need more research to assess health risks from different blood or urine levels. The results shown in the Report should help prioritize and foster research on human health risks that result from exposure to environmental chemicals. For more information about exposure to environmental chemicals including Internet reference sites, see the Chemical and Toxicological Information.