Side by side comparison of micro-vacuum dust collection versus dust wipe for Pb determination in household dust samples.

Abstract

Dust collection is essential for tracing lead sources and determining mitigation measures with accurate sampling and analysis. Two different simulated dust mixtures, Pb-contaminated soil and paint of three different lead concentrations, were used to test the comparability of a modified micro-vacuum sampling method to the currently recommended dust wipe method. The standard dust wipes and a modified micro-vacuum method (20 Lpm flow rate, 2 cm length Nalgene Tygon tube inlet, 2 min per 30 cm × 30 cm area) were used to collect dust and subsequent analysis. Bland-Altman's plots indicated very good agreement between methods, with minimal bias and acceptable variability. For Pb-containing soil dust at 1200 and paint dust at 1000 mg kg^-1 concentration of Pb, methods did not differ significantly. For lower lead concentration samples, the dust extraction method from vacuum cassettes was negatively affected, resulting in significantly lower lead loadings than the dust wipe method; in follow-up studies in selected samples, sonication facilitated more complete extraction (76%-91%) from vacuum cassettes. Overall, results suggested potential for developing a standardized micro-vacuum method with additional benefits for house dust collection.