Hair analysis: exploring the state of the science.

On 12-13 June 2001, the Agency for Toxic Substances and Disease Registry (ATSDR) convened a seven-member panel in Atlanta, Georgia, to review and discuss the current state of the science related to hair analysis, specifically its use in assessing environmental exposures in support of the agency's public health assessment activities. ATSDR invited scientific experts in the fields of hair analysis, toxicology, and medicine to participate in a discussion of such topics as analytical methods, factors affecting the interpretation of analytical results, toxicologic considerations, and data gaps and research needs. The goal of the panel was to determine the overall utility of hair analysis as a tool to evaluate exposure at hazardous waste sites. The principal lesson learned from the meeting was that, for most substances, data are insufficient to predict health effects from the concentration of the substance in hair. The presence of a substance in hair may indicate exposure (both internal and external) but does not necessarily indicate the source of exposure. Thus, before hair analysis can be considered a valid tool for assessing exposure and health impact of a particular substance, research is needed to establish standardized reference ranges, gain a better understanding of biologic variations of hair growth with age, gender, race and ethnicity, and pharmacokinetics, and further explore possible dose-response relationships. ATSDR intends to use the findings of this panel to develop educational materials to support its site work and to encourage researchers to continue to develop methods that may facilitate reliable exposure assessments.