Pentagon surface wipe sampling health risk assessment

Within hours after the terrorist attack on the Pentagon on September 11, 2001, an extensive sampling effort was initiated within the building to include surface wipe sampling for select coplanar polychlorinated biphenyls (PCBs), congeners of polychlorinated dibenzo(p)dioxins and dibenzofurans (dioxins/furans) and lead. A risk-based screening level method was utilized to determine the necessity of additional sampling and to assess the potential for emergency response crews, remediation crews, and returning Pentagon workers to have adverse health impact from exposure to the PCBs, dioxins/furans, and lead on nonporous surfaces. The screening level method included all exposure pathways: dermal absorption, incidental ingestion, and inhalation. Various U.S. Environmental Protection Agency (USEPA) guidance documents provided the basis for the method. The underlying assumptions were that the PCBs, dioxins/furans, and lead were contained in the dust or soot layer found on nonporous surfaces, that sampling results were representative of the surfaces from which they were taken, and that the analytical methods employed were able to detect 100% of these substances. A few of the limitations associated with this method included the lack of toxicity values for dermal absorption and the lack of accurate, discrete dermal-exposure values. Evaluation results indicated that additional sampling was not necessary and that concentrations of PCBs, dioxins/furans, and lead on nonporous surfaces were below levels expected to cause adverse health impacts to emergency response crews, remediation crews, and returning Pentagon workers.