Ultrasonic Extraction/Anodic Stripping Voltammetry for Determining Lead in Dust: Analyses of Field-Sampled Wipes.
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899