- Author
-
McKnight, M. E.
|
Byrd, W. E.
|
Roberts, W. E. E.
|
Lagergren, E. S.
- Title
- Methods for Measuring Lead Concentrations in Paint Films.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Sponsor
- Department of Housing and Urban Development, Washington, DC
- Report
-
NISTIR 89-4209,
December 1989,
122 p.
- Keywords
-
analysis
|
atomic absorption spectroscopy
|
coating
|
detection
|
housing
|
lead
|
lead-based paints
|
measurement
|
microscopy
|
paints
|
x ray fluorescence
- Abstract
- Recent legislation required the U. S. Department of Housing and Urban Development (HUD) to establish procedures to abate lead-based paint in existing HUD-assisted housing. The legislation also required HUD to assess the accuracy, precision, reliability, and safety of methods for measuring lead content of paint films and to investigate the availability of testers and samplers. The National Institute of Standards and Technology was requested to carry out this assessment. After reviewing the literature for possible field methods, two methods were selected for futher testing: chemical spot tests and methods based upon sue of protable x-ray fluorescence (XRF) analyzers. With regard to accuracy and precision of field measurements, it was concluded that 1) spot tests when carried out by an experienced analytical chemistry technician can detect the presence of lead in paint films having concentrations in excess of 1 mg/cm2 about 90 percent of the time, 2) the estimate of the precision of a field measurement procedure using lead-specific portable XRF analyzers (bhased on three replicate readings and substrate correction) for lead concentrtions near 1 mg/cm2 is ± 0.6 mg/cm2 and the estimate of the bias is 0.2 mg/cm2; this results in a 95 percent confidence interval of ± 1.4 mg/cm2, and 3) based upon very preliminary measurements using the latest version of the spectrum analyer protable XRF, the 95 percent confidence interval for field measurements is estimated to be ± 0.5 mg/cm2. In addition to field methods, standard laboratory procedures can be used to measure the lead content of paint samples to within a few percent of the quantity present over a wide range extending from less than 0.1 to over 10 mg/cm2. Because they can have a large effect on the results, sample collection and sample dissolution procedures were also investigated. The results of the assessments and the conclusions and recommendations based upon the results are discussed in this report.