U.S. Environmental Protection Agency nmental Technology Verification ETV Portable Technologies for Measuring Lead in Dust The U.S. EPA Environmental Technology Verification (ETV) Program's Site Characterization and Monitoring Technologies (SCMT) Pilot, which was operated by Oak Ridge National Laboratory (ORNL) under an interagency agreement with EPA, and was an element of the Advanced Monitoring Systems (AMS) Center, has verified the per- formance of six field screening analyzers for lead in dust.1 A technical panel of experts in lead testing, which included representation from the U.S. Department of Housing and Urban Development (HUD), National Institute for Occupational Safety and Health, National Institute of Standards and Technology, American Industrial Hygiene Association, Massachusetts Childhood Lead Poisoning and Prevention Program, and several EPA offices, including the Office of Pollution Prevention and Toxics, assisted with the design of the verification test and the reporting of results. These portable analyzers allow quick identification of lead levels in dust onsite and enable the user to react to potential health risks in a timely manner. Technology Description and Verification Testing The technologies verified by the ETV Program are portable and designed to be used to analyze dust samples in the field. The verified technologies use either X-ray fluorescence (XRF) or anodic stripping voltammetry (ASV). XRF allows for non-destructive analysis of a sample. This technique uses a radioisotope source or X-ray tube to excite lead atoms in the sample. The atoms, in turn, emit characteristic X-rays that are detected, quantified, and identified by the spectrometer. ASV is a destructive analysis method. A test sample is contacted with acid to bring lead into solution. The solution is subsequently mixed with a buffer salt solution. Lead in the solution is plated on and then stripped off an electrode. Each metal will strip from the electrode at a different potential, allowing for its identification, while the amount of current produced is quantified and correlated to sample concentration. Table 1 identifies the six ETV-verified technologies and the technique used by each. A primary objective of the ETV test was to assess whether the participating field portable technologies produced results that were comparable to National Lead Laboratory Accreditation Program (NLLAP) recognized data. During verification testing, 160 dust wipe samples were A verified lead in dust analyzer analyzed. These Environmental, Health, and Regulatory Background of Lead at a Glance Lead is a highly toxic metal that was used for many years in products (e.g., as a pigment in paint products) found in and around homes. Lead may cause a range of health effects, such as behavioral problems and learning disabilities, and, at high levels of exposure, can result in brain damage or death. Research suggests mat the primary sources of lead exposure for most children are deteriorating lead-based paint, lead contaminated dust, and lead contaminated residential soil. Children six years old and under are most at risk because their bodies are growing quickly. The Centers for Disease Control and Prevention have determined in children elevated blood lead levels (BLLs) of 10 micrograms per deciliter or higher are associated with adverse health effects. To address the hazards of lead poisoning, the U.S. Consumer Product Safety Commission banned lead-based paint in 1978. However, homes built prior to 1978 are still in use and may have interior or exterior paint containing lead. In 1992, the U.S. Congress enacted the Residential Lead-Based Paint Hazard Reduction Act. Under this act, EPA and other federal agencies such as HUD established numerical standards for hazardous levels of lead in dust for pre-1978 housing and child- occupied facilities, required disclosure of known lead-based paint and lead-based paint hazards to buyers and tenants, and provided grants for low-income families who occupy lead-based-paint hazards in private housing. The grants include clean-up, control, testing, awareness, and training. wipes contained between 2 and 1,500 micrograms of lead per dust wipe, which is representative of levels found in house dust wipe samples collected using ASTM methods. The ETV Program evaluated the technologies on the following performance parameters: precision, accuracy, comparability to NLLAP recognized laboratory results, detectable blanks, false positive results, false negative results and other parameters. Table 2 summarizes some of the performance data for the individual verified technologies. Additional information is available in the full verification reports and verification summary statements which can be found at http://www .epa.gov/etv/ verifications/vcenterl -22.html. The ETV Program operates largely as a public-private partnership through competitive cooperative agreements with non-profit research institutes. The program provides objective quahty-assured data on the performance of commercial-ready technologies. Verification does not imply product approval or effectiveness. ETV does not endorse the purchase or sale of any products and services mentioned in this document. ------- Table 1 . Verified Portable Technologies for Measuring Lead in Dust Vendor KeyMaster Technologies Monitoring Technologies International Thermo Electron Corporation, NITON Analyzers Business Unit (Formerly NITON LLC) Palintest Verified Technology X-Ray Fluorescence Instrument Pb-Test PDV 5000 Trace Element Analyzer X-Ray Fluorescence Spectrum Analyzer XLt 700 Series X-Ray Fluorescence Spectrum Analyzer XL 700 Series X-Ray Fluorescence Spectrum Analyzer XL 300 Series Scanning Analyzer SA-5000 System Technology Type XRF ASV XRF XRF XRF ASV Selected Outcomes of Verified Portable Technologies for Measuring Lead in Dust • Based on a hypothetical projection of 25% market penetration, the ETV-verified portable measurement technologies could be deployed at up to approximately 9.5 million housing units out of an estimated potential market of 38 million (Jacobs et al. 2002) that were built before 1978 to: - screen for lead hazards (e.g., as part of a lead hazard screen) and assess potential risks (e.g., during a risk assessment). - temporarily clear residences for occupation following abatement or lead hazard control activities followed by final clearance based on fixed site laboratory analysis. - develop a focused and cost-effective sampling and analysis strategy provided the technology is used bv a portable laboratory or field service and measurement organization that has been accredited by NLLAP1. • The information provided by these technologies can assist in the reduction of lead exposure, with associated human health and economic benefits, particularly for children. These technologies can be used to investigate instances of elevated BLLs in children. • ETV verification also can potentially increase acceptance and use of the portable measurement technologies. ETV reports have been cited as a resource for promoting the use of the lead monitoring technologies such as the XRF instruments for residential lead soil and dust testing. Previous ETV verifications of similar technologies have assisted in the development of approved EPA methods for using field portable measurement technologies. 1 The limitations to this assumption is explained on p. 48 of the ETV Case Studies: Demonstrating Program Outcomes. EPA/600/R-06/001. January 2006 Table 2. Performance of Verified Portable Technologies for Measuring Lead in Dust Vendor3 A B C D E F Average relative accuracyb,% 168 to 189 88 to 93 91 to 97 107 to 119 80 to 91 97 to 101 Average relative precisionc,% 15 to 18 21 to 22 7 to 8 8 5 to 8 11 Rate of false positives 26 of 50 7 of 41 Oof 42 27 of 46 Oof 50 9 of 49 Rate of false negatives 15 of 50 19 of 57 36 of 58 4 of 54 39 of 50 18 of 51 Comparability11 slope 0.662 to 1.060 0.885 to 1.074 0.849 to 0.936 1.1 12 to 1.206 0.839 to 0.926 0.977 to 0.995 intercept 66 to 121 -14.345 to 15.633 7.495 to 11. 262 -3.29 to 13.283 5.539 to 6.506 3.076 to 4.775 r2 0.967 to 0.989 0.988 to 0.999 0.999 0.999 0.995 to 1.000 0.999 a Because the ETV Program does not compare technologies, the performance results shown in this table do not identify the technologies associated with each result and are not in the same order as the list of technologies in Table 1. b A result of 100% indicates perfect accuracy relative to the tested lead concentration. c A result of 0% indicates perfect precision. d Comparability of the technologies to the standard test method was evaluated using linear regression analysis. References: U.S. EPA, ETV Case Studies: Demonstrating Program Outcomes. EPA/600/ R-06/001. January 2006 (primary source), http://www.epa.gov/etv/pdfs/ pubhcations/600r06001/600r06001pv.pdf. U.S. EPA, ETV. http://www.epa.gov/etv. U.S. EPA, Lead in Paint, Dust, and Soil. 06 Feb. 2007. http://www.epa.gov/ lead/index.html. Jacobs DE, Clickner RP, Zhou JY, Viet SM, Marker DA, Rogers JW, et al. 2002. The Prevalence of Lead-Based Paint Hazards in U.S. housing. Environ- mental Health Perspectives 110(10):A599-A606. October. ETV Advanced Monitoring Systems Center Robert Fuerst, EPA, fuerst. robert@epa. gov Tel: (919) 541-2220 Amy Dindal, Battelle dindala@battelle. org Tel: (561)422-0113 EPA/600/S-07/028 August 2007 ------- |