Validity of a portable X-ray fluorescence device for analyzing field dust wipe samples for lead

Abstract

Interior dust lead loadings on floors and windowsills are reliable predictors of a child’s blood lead level and an important predictor in “clearance testing” of residences. The portable X-ray fluorescence device is an alternate technique that can provide fast, accurate, and precise results regarding the presence of dust lead hazards in residences. In this paper, we tested the comparability of the portable X-ray fluorescence device against Inductively Coupled Plasma Mass Spectrometry, using the newer lead hazard standards for dust wipe samples. Dust wipe samples (n = 109) collected from floors and interior windowsills of 13 homes were tested by means of a portable X-ray fluorescence device and subsequently analyzed for lead using Inductively Coupled Plasma Mass Spectrometry. Considering Inductively Coupled Plasma Mass Spectrometry as the “gold standard,” the portable X-ray fluorescence device produced an average false negative rate of 27.3% at the new dust lead hazard standards of 10 μg/ft2 for floors, and 100 μg/ft2 for windowsills. There were no false positive results from the portable X-ray fluorescence device at the new dust lead hazard standards. A Bland Altman analysis showed that 96.3% of the data points were within the lower and upper acceptable limits of agreement. The results of the study suggested that the portable X-ray fluorescence device has a good agreement with the Inductively Coupled Plasma Mass Spectrometry method at lower lead concentrations and is appropriate for measuring lead concentrations in field dust wipe samples from homes where lead concentrations are in a lower range.