1.Scope 1.1This practice covers the extraction of lead (Pb) using ultrasonication, heat and nitric acid from a composited sample of up to 4 individual wipe samples of settled dust collected from the same space. 1.2The values stated in SI units are to be regarded as the standard. 1.3 This practice contains notes which are explanatory and not part of mandatory requirements of the standard. 1.4 Note that this practice has been shown to produce mixed results except when used by personnel experienced in its activities and procedures. Like all procedures used in an analytical laboratory, this practice needs to be verified for use and shown to produce acceptable results before being applied to client samples. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
This DRAFT Practice is one of 2 sample preparation methods developed as part of a U.S. Department of Housing and Urban Development (HUD) study of composited wipe sample preparation and analysis. Labs accredited by the American Industrial Hygiene Association Laboratory Accreditation Programs (AIHA-LAP), LLC under the National Lead Laboratory Accreditation Program (NLLAP) were questioned about their methods in use, recruited to assure diversity of methods to be examined, sent a singly-blind set of 4-wipe composited samples, and instructed to digest (and analyze) them using their method currently in use for wipe samples. Upon receipt, the analysis results were examined and found to identify 2 methods that yielded acceptable results versus known lead content. The 2 acceptable methods were documented and their procedures standardized, and sent to participating labs for use in preparation (and analysis) of another set of singly-blind samples. The analysis of composited wipe samples has become of interest as a result of analysis of data collected in a HUD study of clearance following renovation and remodeling activities that created large amounts of leaded dust. A very large portion of the total area of the room containing the work area was sampled (E 1728) using wipes that meet E 1792. Single and various combinations of the resulting clearance lead loading data were examined. It was found that when 2 perimeter and 2 middle-of-the-room randomly-selected loading results were averaged, there was a very high probability that the correct clearance pass/fail conclusion for the room resulted. The probability of getting the correct clearance pass/fail conclusion for the room by this means far exceeded any other means. Users are expected to be lead risk assessors and clearance inspectors working for consulting firms, renovation firms, and government agencies.
Keywordssample preparation; ultrasonic extraction
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
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