Lead in dust

Sources of lead in dust and soil include lead that falls to the ground from the air, and weathering and chipping of lead-based paint from buildings and other structures. Lead in dust may also come from windblown soil. Disposal of lead in municipal and hazardous waste dump sites may also add lead to soil. Mining wastes that have been used for sandlots, driveways, and roadbeds can also be sources of lead. 

EPA has developed standards for lead paint hazards, lead in dust, and lead in soil. To educate parents, homeowners, and tenants about lead hazards, lead poisoning prevention in the home, and the lead abatement process, EPA has published several general information pamphlets. Copies of these pamphlets can be obtained from the National Lead Information Center or from various Internet sites, including http //www.epa.gov/opptintr/lead. 

In environmental health studies conducted near four NPL sites (plus a comparison area for each), ATSDR collected lead concentration data from both environmental media and human body fluids to estimate low-level exposure risk and to document the magnitude of human exposure to lead near those sites. Environmental samples collected at participants homes included drinking water, yard soil, house dust, and house paint body fluids collected from participants included venous blood and urine specimens. For the four sites, mean concentrations of lead in soil ranged from 317 to 529 mg/kg, and mean concentrations of lead in dust ranged from 206 to 469 mg/kg (ATSDR 1995). 

Laxen DP, Lindsay F, Raab GM, et al. 1988. The variability of lead in dusts within the homes of young children. Environ Geochem Health 10 3-9. 

Laxen DP, Raab GM, Fulton M. 1987. Children s blood lead and exposure to lead in household dust and water—a basis for an environmental standard for lead in dust. Sci Total Environ 66 235-244. 

Emond MJ, Lanphear BP, Watts A, Eberly S, and Members of the Rochester Lead-in-Dust Study Group (1997) Measurement error and its impact on the estimated relationship between dust lead and children s blood lead. Environmental Research, 72(1) 82-92. 

Dewalt, G., P. Constant, B.E. Buxton, S.W. Rust, B.S. Lim and J.G. Schwemberger (1995). Sampling and analysis of lead in dust and soil for the Comprehensive Abatement Performance Study (CAPS), in Lead in Paint, Soil and Dust Health Risks, Exposure Studies, Measurement Methods and Quality Assurance, M.E. Beard and A.S.D. Iske (Eds), American Society for Testing and Materials, West Conshohoken, PA, USA, STP 1226, pp. 227-248. 

Duggan MJ and Williams S (1977) Lead in dust in city streets. Sci Total Environ 7 91-97. 

Area Source of lead Lead in air (p.g/m ) Lead in dust (mg/m per 30 days)... 

The authors interpreted this as an indication of the relevance of lead in dust in this particular problem. 

A standard risk assessment, done solely for purposes of prevention, where there is no actual case of lead poisoning, involves inspecting the home for lead paint hazards and testing for lead in dust and soil. This is followed by a detailed listing of what needs to be done to fix or control the lead hazard. The process is described in Chapter 11. 

Whether your sample is collected with a wipe or a vacuum, it should be sent to a laboratory certified by either the NLLAP or ELPAT. To be sure the laboratory is certified to analyze for lead in dust, call the National Safety CounciTs National Lead Information Clearinghouse (NLIC) hotline at 800-424-LEAD or one of the agencies that run the accreditation programs, listed in Appendix B, under Testing/Laboratory Analysis. 

The Environmental Protection Agency (EPA) is required to set limits for lead in dust and soil. Eventually, the EPA will also set standards for lead hazard control activities. But until this happens, HUD is responsible for these standards. 

Ingestion is the main means of intake of lead into the blood stream. Absorption through the skin or in the lungs is minor, and inhaled lead in dust is usually expelled from the lungs in mucous and is... 

Duggan MJ, Williams S (1977) Lead-in-dust in city streets. Sci Total Environ 7 91-97 Dyson SE, Jones DG (1976) Some effect of undernutrition on synaptic development -a quantitative ultudastructural study. Brain Res 167 363-371 Fomon SJ (1974) Infant nutrition, 2nd ed. W.B. Saunders Company, Philadelphia London, p 24... 

Lead in dust, especially interior dusts, is a major pathway for lead exposure of risk populations such as very young children through hand-mouth activity and ingestion or by direct inhalation. Industrial dusts provide exposures for lead workers on the job. 

Lead in dusts was discussed earUer as a factor in producing localized increases in ambient air lead from resuspension. Numerous smdies have... 

Leaded dusts can occur in soils, in the household, on hard exterior surfaces such as streets, and as occupational dusts in the specific context noted above. The ability of lead in dusts to rapidly accumulate on hard surfaces produces both a problem for quantification and a potent potential factor in human lead exposure assessments (U.S. EPA, 1986, Ch. 7). The physical and chemical compositions of dusts as well as the levels of lead are determined in large measure by their origin. It is also typical of dusts that they can deposit onto an almost infinite array of hard surfaces, and as a consequence can accumulate to quite high levels over time. This accumulation can be depicted quantitatively as either concentration or as dust lead loadings. 

Pb in diet on a daily or other time scale entail much larger amounts in terms of relative mass. For example, adults typically will consume only small amounts of lead in dusts and soils, 25—150 mg for various age bands, while ingesting food at a daily rate of 1 kg or more. Consequently, total daily intake of 100 mg of dust having a concentration of 1,000 ppm Pb yields the same Pb intake as 0.1 ppm Pb in 1.0 kg of diet. Other factors differentiating diet Pb from Pb in other media can potentially include a higher relative bioavailability of food Pb once ingested. 

Duggan, M.J., Williams, S., 1977. Lead in dust in city streets. Sci. Total Environ. 7, 91—97. Everson, J., Patterson, C.C., 1980. Ultra-clean isotope dilution/mass spectrometric analyses for lead in human blood plasma indicate that most reported values are artificially high. Clin. Chem. 26, 1603-1607. 

FIGURE 9.1 Typical pathways of childhood exposure to lead in dust and other Pb media inputs in structural equation modeUng. U.S. EPA (1996b), Figure 2.3. 

SOURCE WHAT CONTRIBUTES TO LEAD IN DUST KEY SITES... 

Benefits. The Economic Analysis describes the estimated benefits of the rulemaking in qualitative and quantitative terms. Benefits result from the prevention of adverse health effects attributable to lead exposure. These health effects include impaired cognitive function in children and several illnesses in children and adults. EPA estimated the benefits of avoided incidence of IQ loss due to reduced lead exposure to children under the age of 6. There are not sufficient data at this time to develop dose-response functions for other health effects in children or for pregnant women. The benefits of avoided exposure to adults were not quantified due to uncertainties about the exposure of adults to lead in dust from renovation, repair, and painting activities in these facilities. 

Those studies conducted to date establish a basis for control of lead, pesticides, PAHs, PCBs, and allergens in indoor air and house dust. Track-in and accumulation of pollutants in rugs is an important source of exposure for children lead in dust is the major source of lead for most toddlers. The established benefits from reduced exposure to lead and allergens justify public education to reduce dust from track-in and inside sources as well as pollutants in indoor air. Action to control lead and allergens will reduce exposure to other pollutants in house dust and indoor air. It is possible that a nonregulatory education and outreach program with emphasis on public participation and pollution prevention will be more effective in the home than use of regulations and other traditional methods of pollution control. 

Before it was banned, lead-based paint was the paint of choice for double-hung windows because of its superior adhesive properties (Park and Hicks 1995). But as sashes rub against each other when the lower sash is opened and closed, a fine dust is produced (CDC 2012). This is the source of much lead in dust in older homes (CDC 2012). The dust can be inhaled and ingested by toddlers who accumulate the lead on their hands as they crawl (CDC 2012). Hand-to-mouth activity then results in ingestion (World Health Organization 2010). Dust on floors below windows is covered under the clearance standards set by the U.S. Department of Housing and Urban Development (HUD). After work in a house by a paid contractor that disturbs lead paint, the amount of lead on a floor can be no more than 40 pg per square foot (pg/ft ) interior windowsills can have no more than 250 pg/ft and window troughs can have no more than 400 pg/ft. ... 

Several commercially available spot test kits give semiquantitative results for lead in environmental samples, but these have not been fully evaluated for dust. There is at least one rhodozonate-based kit that, when used properly, gives a positive red or pink eolor in the presence of lead in dust. It is likely that other kits can be adapted to dust analysis, but some modifications may be required. 

There is no certifieation process for laboratories testing the lead content of dust. A program has been initiated by EPA to determine the requirements for such a certification process, and it is likely that laboratory certification will be performed by an independent organization according to these guidelines. This certification will include testing for lead in dust, soil, and paint. 

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