Hair Analysis Panel Discussion: Section 1.1

Section 1
1.1 Background

ATSDR conducts public health assessments to evaluate possible public health implications of contamination associated with hazardous waste sites and other environmental releases. An important step in ATSDR's assessment process is examining exposures to contaminants under site-specific conditions and determining whether people are being exposed to contaminants at harmful levels. In most of the agency's evaluations, the environmental concentration serves as a surrogate for "exposure."

Exposure concentrations, or estimated doses based on exposure concentrations, however, represent only one factor in a continuum of events that ultimately determine whether exposures will result in illness. Other factors include exposure conditions and various pharmacokinetic/pharmacodynamic events (e.g., absorption, distribution, metabolism, excretion), as well as individual variability and susceptibility in the exposed population. To a large extent, ATSDR evaluates these factors qualitatively in its public health assessments.

To refine its assessments and/or to fill data gaps, ATSDR seeks ways to more precisely quantify exposures, such as measuring body burdens of a particular contaminant or its metabolites (e.g., lead in blood or arsenic and its metabolites in urine). On a site-by-site basis, ATSDR evaluates what additional exposure data it might be practical and useful to obtain to further support public health evaluations and ultimately to help determine the disease potential of a particular exposure.

In convening this panel, ATSDR's goal was to determine the overall utility of hair analysis as one such exposure assessment tool. Hearing various points of view will help ATSDR draw conclusions based on the best available science.

ATSDR plans to weigh the information and data presented at the panel meeting and, in the short term (i.e., over the next several months), independently develop some interim guidance for its health assessors and others at ATSDR who are asked by communities about the virtues of hair analysis in understanding exposures to, or the disease potential of, particular chemicals. For the purposes of the panel discussions, ATSDR was not seeking consensus of the panel on any particular issue, but rather scientific input (consistent or varied) for consideration by the agency. Also, the panel was not convened to discuss or evaluate the merits of hair analysis for other purposes (e.g., testing for drugs of abuse or nutritional screening). Again, the focus was on environmental exposures.

See the introductory remarks in Section 2 for additional background information.

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