Evaluation of new portable x-ray fluorescent lead analyzers for measuring lead in paint

Abstract

Portable X-ray fluorescent lead analyzers offer the most cost-effective and adaptable means for the non-destructive detection and measurement of lead in paint in housing. However, commercially available portable lead analyzers have had poor accuracy and precision below lead levels of about 3.0 milligrams of lead per square centimeter of surface area. This is particularly serious because the current operational criteria for lead paint hazard abatement, 1.5 or 2.0 mg lead/cmm aximum (used in many communities), is in this range. They have also performed relatively unsatisfactorily with regard to serviceability and maintenance.Two new portable lead analyzers based on x-ray fluorescence developed elsewhere under HUD contracts have been evaluated.One of the new devices was found to be unacceptable for field use because the prototypes of it were all inaccurate and imprecise, difficult to use and maintain.They were also very bulky and heavy.Although prototypes of the other lead analyzer did not meet all the requirements of the HUD contract, they showed considerable improvement over all previously available instruments in terms of accuracy, precision, ease of operation, and portability. They did, however, have some deficiencies which are discussed in the report.

Potential methods for measuring and detecting lead in existing paint films:

“…Considerable interest was shown in the 1970 's for in-situ measurement of lead in paint with the use of portable x-ray fluorescence (PXRF) instrumentation.Several studies were done in the United States, Canada, and England that used both commercially available PXRF instruments as well as prototype PXRF instrumentation[3][4][5][6][7][8][9][10][11][12].PXRF instruments referenced in the literature for measuring lead in paint films use either 10-25 millicurie cobalt-57 or 5 millicurie cadmium-109 as an excitation source[7]. A typical configuration of a PXRF is shown in Figure 1[13].…”