Standard Operating Procedure for the Turbidimetric Determination of Lead in Paint Extracts

摘要

Exposure to lead (Pb) may adversely impact children's brains, nervous systems, and many organs. An estimated 310,000 U.S. children ages 1 to 5 have elevated blood leads. In the United States, the major exposure pathway for children to Pb is from deteriorated Pb-based paint (LBP), Pb-contaminated house dust, and residential soil. Approximately 40% of all U.S. housing units (about 38 million homes) have some LBP. The simple, commercially produced test kits currently available for home testing for Pb in paint are very sensitive but do not provide quantification of the Pb to meet the specifications in the RRP. There are several field techniques already available for direct (in situ) quantitative analysis of Pb in painted surfaces, including field-portable, X-ray fluorescence, and portable laser microprobe spectrometry.4 The instrumentation for these methods is relatively expensive and requires extensive training. Additionally, there are numerous less expensive field methods available for quantitatively measuring Pb in solution. These include electrochemical reduction/oxidation (anodic stripping voltammetry), complexation (colorimetry), precipitation (gravimetry), or turbidimetry. However, to apply these methods, paint first must be removed quantitatively from the surface, and Pb quantitatively solubilized from the paint. Grinding may be needed to facilitate solubilization. In response to this need for solubilization, a new method has been developed that simultaneously grinds a paint sample and quantitatively extracts the Pb. This procedure is presented in the 'Standard Operating Procedure (SOP) for the Grinding and Extraction of Lead in Paint Using Nitric Acid and a Rotor/Stator System Powered by a High-Speed Motor' (NTIS PB2010-112900).