Using an iron fist against lead dust
In an effort to significantly reduce the amount of lead poisoning incidents affecting children, the U.S. Environmental Protection Agency (EPA) and the U.S. Office of Housing and Urban Development (HUD) have instituted stringent new regulations to lower the acceptable levels of lead-dust in federally owned and/or assisted residences following abatement or renovation projects.
Although everyone is at risk for irreversible damage caused by exposure to high concentrations of lead, children -- especially between one and five years of age -- are the most susceptible, absorbing as much as 30 percent of lead dust through ingestion and approximately 70 percent through inhalation. It is estimated that one million children1 will be poisoned this year alone, primarily through exposure in their homes. Approximately two-thirds of all American homes contain some form of lead-based paint, particularly those built before 1978, when leaded-paint was banned from residential use.
Young children, with their propensity for hand-mouth activity, are most susceptible to lead poisoning from lead-contaminated dust. Lead poisoning is linked to neurological disorders, kidney damage, impaired intellectual and cognitive development, anemia, comas and even death. An aggressive campaign of complete abatement, encapsulation and rigorous maintenance of old painted surfaces is necessary in order to protect our children and ourselves.
Effective September 15, 2000, new regulations by EPA and HUD will enforce a drastic reduction in dust-wipe levels for federally owned property and housing receiving federal assistance that will undergo renovation. This will apply to all housing units built prior to 1978, whether single family homes or rental apartment units. Because lead removal or renovation activities require residual dust levels to be below 40 grams per square centimeters (g/cm2) for floors and 250 g/cm2 for windowsills, lead-abatement contractors will have to be more rigorous in their cleaning to meet these new standards. EPA has also recently passed new regulations that require certification of all lead inspectors and abatement contractors. This certification must be issued by the state where the work is being performed.
Lead poisoning is linked to neurological disorders, kidney damage, impaired intellectual and cognitive development, anemia, comas and even death.
Achieving dust clearance is a key step in the abatement process. Following an initial round of cleaning, dust wipe samples must be collected and sent to an EPA-accredited laboratory for analysis. At this point, the abatement crew leaves the site and all involved must await the results of the off-site analysis. During this process, the occupants or dwelling owners remain in alternative housing until results of the dust wipes are below official clearance levels. If the results are above the clearance levels, the cleaning crew must return and the entire process is repeated until dust wipe samples fall below the required criteria. Residents remain displaced while costs rise with each successive round of cleaning. Clearance failure rates often exceed by 40 percent the current acceptable levels of 100 micrograms per square foot (ug/ft2) for floors and 500 ug/ft2 for windowsills. Reduction in these levels to 40 ug/ft2 for floors and 250 ug/ft2 for sills will result in
higher failure rates, increased abatement costs, disruption of life and additional costs to residents. The problem to be solved is how to ensure drastic reduction or even elimination of failed clearances in the first or second round of cleaning while adhering to the new regulations.
On-site analysis of dust wipes allows contractors to ensure dust lead levels will meet clearance criteria prior to releasing the cleaning crew.
One way to achieve clearance levels early in the abatement process is by taking on-site measurements of dust wipes using x-ray fluorescence (XRF) analyzers. XRF is the only EPA-accepted method for in-situ analysis of lead-based paint. One manufacturer of lead-based-paint XRF analyzers (NITON Corporation, Billerica, MA) has developed and extended the analytical capabilities for on-site testing for lead in dust wipes, soil and air filters. The instrument meets EPA Method 6200 for metals in soil and National Institute of Occupational Safety and Health (NIOSH) Method 7702 for airborne lead analysis. Evaluations by two research universities (University of Cincinnati, Saint Louis University) to assess dust wipe performance are in process.1
On-site dust wipe testing offers cost savings to the lead abatement industry. A key cost escalation in the clearance process occurs when the property fails dust clearance. In this case, the abatement contractor must return to the site, re-clean and re-submit clearance wipes. During this period, the occupants of the dwelling are kept in temporary housing, often at local, state or federal government expense. On-site testing with portable XRF provides a way to eliminate failed clearances while complying with regulations that require wipes to be analyzed by an EPA-accredited laboratory. On-site analysis of dust wipes allows contractors to ensure dust lead levels will meet clearance criteria prior to releasing the cleaning crew. In addition, the ability to monitor on-site can "teach" crews how to clean more effectively by providing instant feedback on the quality of their cleaning process. This avoids the unpleasant and expensive experience of learning that dust levels were too high days after the crew has vaca
ted the site. Because the XRF test is non-destructive, the same samples can be analyzed by an accredited laboratory to document clearance. For example, a typical protocol requires that if lead levels measured on-site are within 25 percent of clearance levels, or exceed clearance levels, inspectors advise the contractor to continue cleaning, as clearance failure is highly probable. When XRF testing determines levels are less than 75 percent of clearance levels, inspectors can send those wipes to an accredited laboratory for confirmatory analysis for final clearance with a high confidence of obtaining clearance.
Table 1. Performance of portable XRF
with dust wipe analysis
|XRF performance data
Limit of detection (LOD) -- 10 ug/wipe
Accuracy -- +15 percent
Testing time -- 4, 1-minute tests/wipe
On-site XRF dust wipe protocol
The operator first collects and then folds the dust wipe following the American Society for Testing and Materials (ASTM) Method 1728-95 and then places it in a sample holder. The customized testing stand holds the sample in place for XRF analysis. Table 1 lists the accuracy, limit of detection (LOD) and testing time required for each analysis. The test for each wipe takes four minutes with an average house requiring seven dust wipe samples to be taken. The XRF analysis is non-destructive. The final dust wipes can be sent to off-site laboratories for confirmatory analysis, which is required for clearance.
Portable XRF can provide accuracy comparable to EPA-accredited laboratories, as shown by the manufacturer's participation in the EPA Environmental Lead Proficiency Analytical Testing Program (ELPAT) (see Figure 1). In the ELPAT program, participant laboratories are sent unknown samples to test and results are reported to NIOSH for evaluation and rating of each laboratory as proficient. NIOSH then produces proficiency ranges. If submitted results are within these proficiency ranges for three out of four samples, the laboratory is rated proficient for that quarterly round. The manufacturer has achieved proficiency every round for the past three years, which demonstrates portable XRF can meet laboratory accuracy requirements.
In an effort to reduce and ultimately eliminate childhood lead poisoning incidents, these new regulations require additional cleaning and testing. Having on-site, non-destructive methods of analysis, will lead to faster and more efficient lead abatement efforts of federally funded housing. Additionally, this will influence private homeowners to take a more proactive position to reduce the risk of lead poisoning during renovation and repair efforts. Part of the new regulations will also require home owners to notify buyers of the presence of lead and require full risk assessments in federally funded or owned homes that were built prior to 1960.
Reliance on off-site laboratory analysis alone is costly and time consuming for inspectors and contractors. The ability to test on-site, in real time, will be valuable in achieving timely clearances. On-site testing, as an adjunct to traditional lab analysis, will very likely become standard procedure in all abatement efforts.
1 President's Task Force on Environmental Health Risks and Safety Risks to Children
2 S. Clark et al., Use of a Field Portable X-ray Fluorescence Analyzer to Determine the Concentration of Lead and Other Metals in Soil Samples, Ann. Agric. Environ. Med, 1999, 6, 27-32.
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This article appeared in Environmental Protection, Volume 11, Number 10, October 2000, Page 66.
This article originally appeared in the 10/01/2000 issue of Environmental Protection.