Field evaluation and comparison of five methods of sampling lead dust on carpets

Five methods of sampling lead-contaminated dust on carpets were evaluated and compared in 33 New Jersey homes of children with elevated blood lead levels. The five sampling methods were (1) wipe, (2) adhesive label, (3) C18 sheet, (4) vacuum, and (5) hand rinse. Samples were collected side by side on the same carpets within the homes. Among the five methods the wipe and vacuum methods showed high percentages of detectable samples, good reproducibility, and significant correlations with other methods. C18 sheets and adhesive labels collected the least quantity of lead dust, with high percentages of undetectable samples. Because of the limited ability of sampling lead on carpets and the relatively high cost for laboratory analysis, C18 sheets or adhesive labels are not considered feasible sampling techniques. The hand rinse method also was not feasible for carpet sampling, because it was difficult to conduct in the field and laboratory, and it was subject to inconsistency and cross contamination. Wipes, which collected lead dust from carpet surfaces, were believed to be the most appropriate method for measuring lead from carpets accessible to children. However, because of the low pickup from carpets, wipes may not be an appropriate measuring tool to assess the levels of total lead contamination in carpets. The authors recommend using surface wipe sampling to measure accessible lead from carpets for exposure assessment, and vacuum sampling to obtain the information on total lead accumulation.