As the number of human biomonitoring studies begins to escalate, many challenges surround their effective use, according to a new report from the National Research Council. Biomonitoring means measuring a chemical or its metabolite in humans, usually in blood or urine, for assessing exposures to chemicals. Interpreting what biomonitoring data mean in terms of public health is often difficult, the report says. The ability to detect a chemical in humans often exceeds the ability to determine whether that substance causes a health risk or to evaluate the source of exposure. The design of biomonitoring studies is often problematic, the report says, as there is no coordinated, public-health-based strategy for selecting the chemicals to be measured. The report recommends development of an approach for selecting chemicals based on their potential to cause harm and on widespread population exposure. It also wants studies conducted that could help interpret the risk from chemicals in the environment. In addition, research is needed to understand how to communicate the results of biomonitoring studies effectively, it says. The American Chemistry Council praises the report. "We believe the report provides a very useful benchmark for future as well as current research efforts," says Richard A. Becker, ACC's senior toxicologist. The report can be found online at newton.nap.edu/catalog/11700.html.