Lead-based paint concentrations

Releases from lead-based paints are frequently confined to the area in the immediate vicinity of painted surfaces, and deterioration or removal of the paint can result in high localized concentrations of lead in indoor air (from sanding and sandblasting) and on exposed surfaces. 

In the late 1980s, the U.S. Department of Housing and Urban Development (HUD) conducted a national survey of lead-based paint in housing. The EPA subsequently sponsored a comprehensive technical report on the HUD-sponsored survey to provide estimates of the extent of lead-based paint in housing. In the EPA report, a home is considered to have lead-based paint if the measured lead concentration on any painted surface is 1.0 mg/cm2 or greater. The EPA report estimates that 64 million ( 7 million) homes, or 83% ( 9%) of privately-owned housing units built before 1980, have lead-based paint somewhere in the building. Approximately 12 million ( 5 million) of these homes are occupied by families with children under the age of 7 years. Approximately 49 million ( 7 million) privately owned homes have lead-based... 

In addition, the technology should not be used on materials containing friable asbestos, polychlorinated biphenyls (PCB) or lead-based paints, galvanized sheet metal (when heated above 700°F), electrical wiring, wood, vermin excrement, or highly concentrated explosives (e.g., explosives conflned within a pipe). 

Worldwide pollutant of the at- mosphere. concentrated in urban areas from the combustion of tetraethyl lead in gasoline local pollutant "j from mines some poisoning from lead-based paint pigments. 

The exposure to lead based paints and subsequent lead nephropathy and encephalopathy, in the USA, is concentrated in substandard housing [162]. Individuals at the lower end of our economic ladder often are denied access to preventative health care thus putting them at additional risk for toxin exposure. Another example is the consumption of "moonshine" whiskey that has been associated with the development of lead nephropathy [167]. 

The definitions are in 40 C.ER. 745.223. In October 2009 the EPA said that it intends to lower the concentration of lead necessary for a determination that paint is lead-based paint. See http //www.epa.gov/oppt/chemtest/pubs/petitions.html. 

The OSHA standard requires employers to provide initial and annual training to all anployees exposed to an airborne concentration of lead of 30 pg/m averaged over an 8 h period. In some old facilities, exposure can come from lead-based paint or lead-soldered pipe connections. Construction and renovation projects can release lead particles into the air. Hospital departments of nuclear medicine use lead molds in patient treatment. Organizations must confine lead to a specific area. Decontamination and shower facilities should be provided to keep lead from being tracked to other areas. Provide respiratory protection and protective clothing wherever there is known exposure potential. 

Not only are older homes more likely to have lead-based paint, but the concentration of lead in the paint also tends to be higher the older the home is. Before 1950, paint often contained as much as 50% lead. In the mid-1950s, manufacturers decreased the concentration of lead in their paints. In 1955, many paint manufacturers adopted a volun-... 

Thomas looked for lead (as a constituent of lead azelate) at the steel-rust interface in an attempt to confirm this theory. Samples coated with lead-based paint were exposed for three years and then cross-sections were examined in a LAMMS however, lead was not detected at the interface. As Thomas points out, this finding does not eliminate the mechanism as a possibility lead could still be present but in levels below the 100 ppm detection limit of the LAMMS [30,31]. Appleby and Mayne have shown that 5 to 20 ppm of lead azelate is enough to protect pure iron [25]. The levels needed to protect rusted steel would not be expected to be so low, because the critical concentration required for anodic inhibitors is higher when chloride or sulphate ions are present than when used on new or clean steel [35]. Possibly, a level between 20 and 100 ppm of lead azelate is sufficient to protect the steel. Another point worth considering is that the amounts of lead that would exist in the passive film formed by complex azelates, suggested by Appleby and Mayne, has not been determined. The lead soaps/lead azelate theory appears to be the most likely mechanism to explain how red-lead paints protect rusted steel. 

The determination of the lead content of teeth provides another means of assessing exposure to this element and Shapiro et al. [19] found from lead analysis of dentine, that the lead level in contemporary teeth was related to the degree of industrialisation in the community. Furthermore, a comparison of teeth from a modern industrial population with the teeth of non-industrialised Indians of Lacandon forest in Mexico revealed a 45-fold difference in median lead level, the concentration in the Indians teeth being comparable to that in prehistoric populations. In a study in St. Louis of the sources of lead leading to enhancement of lead levels in the deciduous teeth of children in different environments, Lockeretz [20] found high lead levels in teeth among children within areas with high levels of lead available from lead-based paint, and concluded that this was a main source. No effect on tooth content attributable to lead from motor vehicle exhausts was detected. 

Final report Lead hazard control plan or certification of lead-based paint compliance Lead concentrations for each surface tested... 

In the 2006 Proposal, EPA noted that it would look to ASTM International s E1828, Standard Practice for Evaluating the Performance Characteristics of Qualitative Chemical Spot Test Kits for Lead in Paint, or equivalent for a validation method for test kits. With the input of stakeholders, EPA is adapting this ASTM Standard for use in the laboratory validation program. The testing protocol will consist of an evaluation of the performance of the test kits, using the manufacturer s instructions, on various substrates, such as wood, steel, drywall, and plaster, with various lead compounds, such as lead carbonate and lead chromate, at various lead concentrations above and below regulatory threshold for lead-based paint. 

Lead antimonate [13510-89-9] (Naples yellow), Pb2(Sb0 2> mol wt 993.07, d = 6.58g/cm, is an orange-yeUow powder that is insoluble in water and dilute acids, but very slightly soluble in hydrochloric acid. Lead antimonates are modifiers for ferroelectric lead titanates, pigments in oil-base paints, and colorants for glasses and glazes (see Colorants for ceramics). They are made by the reaction of lead nitrate and potassium antimonate solutions, followed by concentration and crystallization. 

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