Comparison of wipe and cyclone methods for the determination of lead in residential dusts

Many sampling and analytical methods have been used to assess lead-containing house dust, an important source of lead exposure in U.S. children; no one method has been adopted as the standard method. Multiple wipe and vacuum-based methods have been used in field studies, yet few studies characterize the relationships between the various methodologies so that results can be compared across studies. This study compares estimates of lead loadings (PhD, milligrams per square meter) based on a frequently used wipe dust collection method with those of a high volume cyclone sampling device. Seventy-seven pairs of side-by-side dust samples collected from uncarpeted floors, window sills, and window wells in seven urban dwellings were used for the comparison. The correlation of the natural logarithms of the cyclone and wipe PhD estimates was 0.90. Cyclone PhD estimates tended to be higher than the corresponding wipe PhD estimates for all surface types except smooth surfaces with low (<1 nig/'m2) PhD. Geometric mean (GM) cyclone PhD estimates were higher than GM wipe PhD estimates for floors, window sills, and window wells by factors of 2.5, 4.2, and 10.4, respectively. Systematic differences in estimates of dust lead levels across methodologies, such as those observed in this study, have important practical implications for standard setting as well as for risk assessment, lead remediation, and clearance testing in residences and buildings.