NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Ultrasonic Extraction/Anodic Stripping Voltammetry for Determining Lead in Dust: Analyses of Field-Sampled Wipes.


pdf icon Ultrasonic Extraction/Anodic Stripping Voltammetry for Determining Lead in Dust: Analyses of Field-Sampled Wipes. (699 K)
Rossiter, W. J., Jr.; Toman, B.; McKnight, M. E.; Emenanjo, I.

NISTIR 7109; 33 p. October 2004.

Keywords:

anodic stripping voltammetry (ASV); building technology; dust wipes; dust; field study; lead containing dust; lead recovery; operator effect; tests; ultrasonic extraction (UE)

Abstract:

Knowledge of the amount of lead in settled dust is important in clearance examinations, risk assessments, and related activities wherein decisions are made regarding lead hazards in houses and related buildings. At present, analyses of lead in dust are normally performed in laboratories, since quantitative methods are not readily field-portable. In recent years, field portable ultrasonic extraction/anodic stripping voltammetry (UE/ASV) has been suggested as a candidate procedure for field analysis of dust wipe specimens. However, the reliability of UE/ASV analyses of field dust wipe specimens has not been demonstrated. The present study compared the results of ASV analyses of UE extracted field-sampled dust wipes against those of inductively coupled plasma (ICP) atomic emission spectrometry analyses of the same extract solutions. The main objective of the study was to investigate whether lead in dust wipe specimens obtained in the field can be efficiently and effectively extracted, and reliably quantified using common UE/ASV field procedures when the analyses are performed by certified risk assessors. The U.S. Department of Housing and Urban Development (HUD) sponsored the research because of the benefits to be gained in having available a reliable, practical method for on-site analysis of lead in dust in houses and related buildings. In a preliminary laboratory phase, data on the use of an ICP procedure for estimating the true values of lead in dust wipe specimens were obtained. Experimental variables were: dust wipe, leadcontaining certified reference material (CRM), specimen lead level, and filter treatment (i.e., filtering versus no filtering) of the UE extracts before ASV analyses. Lead recoveries determined by both ASV and ICP analyses were compared. The effects of wipe and lead level were significant, whereas the effects of CRM and filter treatment were insignificant. All ICP recoveries were quantitative (100% - 20% of the lead applied to the wipe), whereas only 72% of the ASV measurements were quantitative. In the field phase, NIST research staff along with three certified lead risk assessors, who had participated in a previous NIST dust wipe study, sampled lead-containing dust from houses using the same dust wipe products used in the laboratory phase. Three experimental variables were examined: operator, wipe, and filter treatment of the UE extract. Percent lead recoveries by ASV analysis were calculated relative to the lead contents determined by ICP; 88% of the recoveries were quantitative. None of the three variables was significant when the entire data set was considered. A filter treatment effect was present for a data subset comprised of specimens found to have less-than-500 mg of lead. Based on analyses of the entire data set and also on the less-than-500 mg data subset, the probabilities of a future ASV analysis yielding a result within - 25% of an ICP result were estimated to be 0.93 and 0.96, respectively. A recommendation for increasing the efficacy of the UE/ASV protocol is given.