Dust Lead Loading Research Articles

Relationship between residential dust-lead loading and dust-lead concentration across multiple North American datasets

Dust-lead monitoring studies typically report values as either dust-lead loadings (μg/ft2) or as dust-lead concentrations (μg/g). This study presents an approach for estimating dust-lead concentrations, when only dust-lead loading values are available. A literature search identified five large studies (>200 homes) that contained original data for both dust-lead loading and dust-lead concentration, and could be used to develop an empirically-based loading to concentration (LTC) model. The R2 values, standard error of the regression, slope, and intercept were improved when these original data sets were refined and pooled together. An additional thirty-two studies had summary statistics available for both dust-lead loading and dust-lead concentration, which enabled an independent evaluation of the LTC model. Despite differences in study design, sampling method, and analytical procedures, the LTC model made consistent predictions across studies. Reported central-tendency summary statistics from the independent evaluation data sets showed that measured central tendency dust-lead concentrations from these studies were similar to predicted dust-lead concentrations using the LTC model. Across 142 paired dust-lead loading and dust-lead concentration values from the evaluation datasets, slightly more than 90% of estimated dust-lead concentration values fell within a 90% prediction interval. These results indicate that, when only dust-lead loading values are available, the LTC model provides a reasonable approach for estimating dust-lead concentrations. A limitation of this approach is the greater uncertainty at high dust-lead loadings, caused by variability in total dust loadings (g/ft2) that result in one dust-lead loading value being linked to a range of dust-lead concentration values.

Improving the Confidence Level in Lead Clearance Examination Results through Modifications to Dust Sampling Protocols

Abstract Multiple pre-cleaned, four-room residential containments were each subjected to a single high-dust generating activity involving lead-based paint. After dust generation, a geometric wipe sampling grid was used, with a target of 8 interior and 8 perimeter samples in each room, to assess dust-lead on the floors. The containment was then cleaned using the “High Efficiency Particulate Air (HEPA) vacuum/3-bucket wet-mop/HEPA vacuum” procedure found in the U.S. Dept. of Housing and Urban Development Guidelines. Post-cleaning (clearance) floor wipe samples were then taken at side-by-side locations to the pre-cleaning samples. It was found that: [1] floor dust-lead along the perimeters of rooms was three times more difficult to clean than dust-lead from the interiors of the rooms; [2] post-cleaning dust-lead loadings tended to be higher along the perimeters of the rooms than in the interiors of the rooms such that clearance failure was much more likely for individual floor samples collected along the perimeters; and [3] four-wipe composite sampling within each room (two randomly selected from the perimeter and two randomly selected from the interior) provided a very reliable method for detecting clearance failure (99% or greater) versus a randomly selected single wipe sample per room (50% or less).

Making the Needed Linkages and Economic Case for Continued Lead-Paint Abatement

Making the Needed Linkages and Economic Case for Continued Lead-Paint Abatement

Lead loadings in household dust in Delhi, India

Lead in household dust is dangerous to children who ingest lead from playing close to the ground, and having frequent hand-to-mouth contact. Although there have been several investigations of lead levels in India in air, blood and new paint, the literature is sparse on the levels of lead in household dust. This study analyzed 99 samples of dust taken from bare floors and 49 samples of dust taken from windowsills in a cross-section of Delhi, India houses for lead loadings. The arithmetic mean of lead loading for floor samples and windowsill dust samples was found to be 36.24 microg/ft(2) and 129.5 microg/ft(2), respectively. The geometric mean of dust lead loading for floor and interior windowsill samples was found to be 19.7 microg/ft(2) and 75.5 microg/ft(2), respectively. Comparing the results with US geometric mean dust lead levels from a national cross-section of US housing, which in 2000 were 1.1 microg/ft(2) and 9.4 microg/ft(2) on floors and windowsills, respectively as reported by Jacobs et al. (2002) suggests that the lead content of the dust in Delhi homes is much higher than that in the national data in the US and that the levels pose a hazard to children. Practical Implications The present study is first of its kind in this part of the world. In the context of ongoing efforts to eliminate lead from paints worldwide this research will help the scientists and policy makers in assessing the Children's exposure to lead in developing country as well. Since more than one half of the housing units tested had at least one dust lead sample exceeding US health-based standards, health care providers and public health officials need to give attention to possible lead poisoning in Delhi children. Routine blood lead screening of children should follow recommended public health practice for children at risk. Additional larger-scale studies are needed in Delhi and elsewhere to determine how representative these findings are and to attempt to delineate the sources of the high dust lead which are expected to vary depending on the location. Knowledge of the sources is needed to appropriately allocate resources. From other studies performed in India it is likely that lead-based paint is one of the sources and its continued use should be discontinued.

Exposure of U.S. Children to Residential Dust Lead, 1999–2004: I. Housing and Demographic Factors

BackgroundLead-contaminated house dust is a major source of lead exposure for children in the United States. In 1999–2004, the National Health and Nutrition Examination Survey (NHANES) collected dust lead (PbD) loading samples from the homes of children 12–60 months of age.ObjectivesIn this study we aimed to compare national PbD levels with existing health-based standards and to identify housing and demographic factors associated with floor and windowsill PbD.MethodsWe used NHANES PbD data (n = 2,065 from floors and n = 1,618 from windowsills) and covariates to construct linear and logistic regression models.ResultsThe population-weighted geometric mean floor and windowsill PbD were 0.5 μg/ft2 [geometric standard error (GSE) = 1.0] and 7.6 μg/ft2 (GSE = 1.0), respectively. Only 0.16% of the floors and 4.0% of the sills had PbD at or above current federal standards of 40 and 250 μg/ft2, respectively. Income, race/ethnicity, floor surface/condition, windowsill PbD, year of construction, recent renovation, smoking, and survey year were significant predictors of floor PbD [the proportion of variability in the dependent variable accounted for by the model (R2) = 35%]. A similar set of predictors plus the presence of large areas of exterior deteriorated paint in pre-1950 homes and the presence of interior deteriorated paint explained 20% of the variability in sill PbD. A companion article [Dixon et al. Environ Health Perspect 117:468–474 (2009)] describes the relationship between children’s blood lead and PbD.ConclusionMost houses with children have PbD levels that comply with federal standards but may put children at risk. Factors associated with PbD in our population-based models are primarily the same as factors identified in smaller at-risk cohorts. PbD on floors and windowsills should be kept as low as possible to protect children.

Exposure of U.S. Children to Residential Dust Lead, 1999–2004: II. The Contribution of Lead-Contaminated Dust to Children’s Blood Lead Levels

BackgroundThe U.S. Centers for Disease Control and Prevention collected health, housing, and environmental data in a single integrated national survey for the first time in the United States in 1999–2004.ObjectivesWe aimed to determine how floor dust lead (PbD) loadings and other housing factors influence childhood blood lead (PbB) levels and lead poisoning.MethodsWe analyzed data from the 1999–2004 National Health and Nutrition Examination Survey (NHANES), including 2,155 children 12–60 months of age with PbB and PbD measurements. We used linear and logistic regression models to predict log-transformed PbB and the odds that PbB was ≥ 5 and ≥ 10 μg/dL at a range of floor PbD.ResultsThe population-weighted geometric mean (GM) PbB was 2.0 μg/dL (geometric standard error = 1.0). Age of child, race/ethnicity, serum cotinine concentration, poverty-to-income ratio, country of birth, year of building construction, floor PbD by floor surface and condition, windowsill PbD, presence of deteriorated paint, home-apartment type, smoking in the home, and recent renovation were significant predictors in either the linear model [the proportion of variability in the dependent variable accounted for by the model (R2) = 40%] or logistic model for 10 μg/dL (R2 = 5%). At floor PbD = 12 μg/ft2, the models predict that 4.6% of children living in homes constructed before 1978 have PbB ≥ 10 μg/dL, 27% have PbB ≥ 5 μg/dL, and the GM PbB is 3.9 μg/dL.ConclusionsLowering the floor PbD standard below the current standard of 40 μg/ft2 would protect more children from elevated PbB.

Selecting a Lead Hazard Control Strategy Based on Dust Lead Loading and Housing Condition: I. Methods and Results

A methodology was developed to classify housing conditions and interior dust lead loadings, using them to predict the relative effectiveness of different lead-based paint hazard control interventions. A companion article in this issue describes how the methodology can be applied. Data from the National Evaluation of the HUD Lead Hazard Control Grant Program, which covered more than 2800 homes in 11 U.S. states, were used. Half these homes (1417) met the study's inclusion criteria. Interior interventions ranged from professional cleaning with spot painting to lead abatement on windows, and enclosure, encapsulation, or removal of other leaded building components. Modeling was used to develop a visual Housing Assessment Tool (HAT), which was then used to predict relative intervention effectiveness for a range of intervention intensities and baseline floor and windowsill dust lead loadings in occupied dwellings. More than 117,000 potential HATs were considered. To be deemed successful, potential HATs were required to meet these criteria: (1) the effect of interior strategy had to differ for HAT ratings of good vs. poor building condition and/or baseline dust lead loadings; (2) the HAT rating had to be a predictor of one year post-intervention loadings; (3) interior intervention strategy had to be a predictor of one-year loadings; (4) higher baseline loadings could not be associated with lower one-year loadings; and (5) neither exterior work nor site/soil work could result in higher predicted one-year loadings for either HAT rating. Of the 1299 HATs that met these criteria, one was selected because it had the most significant differences between strategy intensities when floors and sills were considered together. For the selected HAT, site/soil work was a predictor of one-year loadings for floors (p = 0.009) but not for sills (p = 0.424). Hazard control work on the building exterior was a predictor of both sill and floor one-year loadings (p = 0.004 and p < 0.001, respectively). Regardless of the type of interior intervention strategy, interior work was a predictor of both floor and sill one-year loadings (each p ≤ 0.001).

Selecting a Lead Hazard Control Strategy Based on Dust Lead Loading and Housing Condition: II. Application of Housing Assessment Tool (HAT) Modeling Results

In Part I in this issue, modeling was used to identify a Housing Assessment Tool (HAT) that can be used to predict relative intervention effectiveness for a range of intervention intensities and baseline dust lead loadings in occupied dwellings. The HAT predicts one year post-intervention floor and windowsill loadings and the probability that these loadings will exceed current federal lead hazard standards. This article illustrates the field application of the HAT, helping practitioners determine the minimum intervention intensity needed to reach “acceptable” one year post-intervention levels, with acceptability defined based on specific project needs, local needs, regulations, and resource constraints. The HAT is used to classify a dwelling's baseline condition as good or poor. If the average number of interior non-intact painted surfaces per room is ≥2, then the dwelling is rated as poor. If exterior windows/doors are deteriorated and the average number of exterior non-intact painted surfaces per building side is ≥5, then the dwelling is rated as poor. If neither of these conditions is true, then the dwelling's HAT rating is good. The HAT rating is then combined with baseline average floor loading to help select the treatment intensity. For example, if the baseline floor loading is 100 μg/ft2 (1,075 μg/m2 and the HAT rating is poor, the probability that the one-year floor loading exceeds the federal standard of 40 μg/ft2 (430 μg/m2 is 27% for a high-intensity strategy (i.e., window lead abatement with other treatments) but is 54% for a lower-intensity strategy (i.e., cleaning and spot painting). If the HAT rating is good, the probability that the one-year floor loading exceeds 40 μg/ft2 is approximately the same for low-and high-intensity strategies (18% for window lead abatement with other treatments compared with 16% for cleaning and spot painting). Lead hazard control practitioners can use this information to make empirically based judgments about the treatment intensity needed to ensure that one year post-intervention loadings remain below federal standards.

Immediate and one-year post-intervention effectiveness of Maryland's lead law treatments

A 1994 Maryland law prescribes a lead-based paint risk reduction standard for pre-1950, privately owned rental housing. This standard, applied at each tenancy change, can be met by sampling to verify that dust lead loadings are within acceptable limits or by performing specific lead hazard reduction treatments, followed by an independent visual inspection without dust sampling. We evaluated the ability of visual inspection to predict treatment completion and dust lead loadings. Fifty-two Baltimore housing units were enrolled and received the law-specified treatments. Before treatment, study risk assessors conducted visual assessments and dust lead wipe sampling in each unit. After treatment, Maryland-certified visual inspectors conducted the law's required visual inspection, followed by the study risk assessors, who performed a separate visual assessment and collected dust wipe samples. One year later, study risk assessors performed another visual assessment and dust wipe sampling ( n=34). Dust lead loadings declined significantly immediately after prescribed lead treatments were implemented. Fifty-three percent, 20%, and 47% of units had at least one sample that exceeded 1995 EPA/HUD floor, window sill and window trough clearance guidance of 100, 500 and 800 μg/ft 2, respectively. Overall, 73% of units had one or more immediate post-intervention single surface sample results exceeding the 1995 clearance values that were in effect at the time of the study. One-year post-intervention loadings remained significantly below pre-intervention levels for floors but not window sills or troughs. Visual assessments alone, without dust lead testing, did not ensure that prescribed treatments were completed or that dust lead loadings were below clearance values.

Evaluation of HUD-funded lead hazard control treatments at 6 years post-intervention

The Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program (Evaluation) was a HUD-funded study of the effectiveness of lead hazard control (LHC) treatments conducted by 14 grantees in communities across the country. A stratified random sampling scheme was used to select treated units at four grantee sites for continued environmental assessment at 6 years post-intervention. The study compared the relative effectiveness after 6 years of the different classes of interventions used by the grantees, after controlling for such factors as housing conditions and characteristics and resident and neighborhood characteristics. Geometric mean dust-lead levels on floors and window sills were 11% and 23% lower, respectively, at 6 years post-intervention than at any preceding point following the intervention. Although geometric mean window trough dust-lead levels were slightly higher at 6 years post-intervention than at other post-intervention time periods, they were still over 75% lower than before intervention. Treatment at more-intensive levels was associated with lower window sill and window trough dust-lead levels; however, statistical modeling found no significant difference in floor dust-lead loadings over time between the levels of treatment; however, significant differences in window sill and window trough dust-lead levels between treatment levels were evident. Findings from the 6-Year Extension study indicate that across all grantees and treatment strategies the treatments applied were effective at significantly reducing environmental lead levels on floors, window sills, and window troughs at least 6 years following the intervention.

The Influence of Common Area Lead Hazards and Lead Hazard Control on Dust Lead Loadings in Multiunit Buildings

Owners of multiunit buildings built before 1978 that have interior common areas, and who receive certain forms of federal assistance are generally required to address lead-based paint hazards in those common areas. This study examines the relationships between common area paint and dust lead levels and the floor dust lead loadings in associated dwelling units, as well as the effects of lead hazard control treatments in common areas. This article presents data from common areas in 145 low-income, mostly pre-1940, multiunit buildings with 342 associated dwellings in the U.S. Department of Housing and Urban Development Lead Hazard Control Grant Program at preintervention, clearance, and 1-year postintervention. Interior common areas in these multiunit buildings were not as well maintained as the dwellings in the buildings. At preintervention, a higher percent of the interior common areas had non-intact, lead-based paint on windows, doors and trim, and other interior components than in associated dwellings (95% versus 85%; 78% versus 67%; and 85% versus 62%). Common areas had preintervention entry and interior (i.e., nonentry) floor dust lead loadings more than four times higher than in dwelling units (128 versus 30 μ g/ft2; 130 versus 28 μ g/ft2) while 1-year postintervention common area dust lead loadings are four to six times that of dwelling dust lead loadings (41 versus 11 μ g/ft2; 44 versus 8 μ g/ft2). Windowsill dust lead loadings in common areas were twice the loadings in dwelling units at preintervention and 1-year postintervention (756 versus 383 μ g/ft2; 154 versus 68 μ g/ft2). Interior common area treatments reduced geometric mean common entry dust lead loadings 71% from preintervention to clearance, and maintained those reduced levels from clearance to 1-year postintervention. Higher level interventions were not more effective than low-level interventions in reducing preintervention levels to clearance or 1-year postintervention. This study demonstrates that interior common areas in the multiunit buildings examined contain substantial amounts of deteriorated lead-based paint and dust. Remediation of common areas can effectively reduce those hazards.

Effectiveness of lead-hazard control interventions on dust lead loadings: Findings from the evaluation of the HUD Lead-Based Paint Hazard Control Grant Program

From 1994 to 1999, the Evaluation of the US Department of Housing and Urban Development Lead-Based Paint Hazard Control Grant Program studied the intervention experiences of over 2800 homes in 11 states in the USA. Each interior intervention was categorized as (in order of increasing intensity) (a) cleaning/spot painting; (b) complete repainting; (c) complete repainting plus window treatments; (d) window abatement plus treatments to other components; (e) abatement of all lead-based paint hazards; or (f) abatement of all lead-based paint. Complete dust testing and environmental data were available for 1034 and 278 dwellings through 12 and 36 months postintervention, respectively. Strategies ranging from complete repainting to window abatement plus other treatments reduced geometric mean preintervention windowsill and floor dust lead loadings up to 36 months postintervention (reductions for complete repainting, from 16 to 5 μg/ft 2 on floors and 182 to 88 μg/ft 2 on sills; for window abatement plus other treatments, 27–8 μg/ft 2 on floors and 570–124 μg/ft 2 on sills). Full abatement reduced windowsill and floor loadings from baseline to 12 months postintervention [95–6 μg/ft 2 on floors and 518–30 μg/ft 2 on sills (data were not available for this strategy at 36 months)]. Window lead-hazard abatement was the most effective measure to reduce dust lead loadings on windows, but this treatment would need to be performed in conjunction with treatments to floors as well as exterior and soil treatments for the most effective control of dust lead on floors.

Residential Dust Lead Loading Immediately After Intervention in the HUD Lead Hazard Control Grant Program

At the conclusion of most lead hazard control interventions in federally assisted housing built before 1978, a certified clearance examiner must verify that the lead hazard control work was completed as specified and that the area is safe for residents, a process referred to as clearance. This study explores the experience of 14 grantees participating in the Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program in passing clearance. The study also considers how preintervention lead levels (interior dust and paint), building condition/characteristics, and the scope of work influenced initial clearance dust lead loadings and clearance rates. At the initial clearance inspection, 80% of the 2682 dwellings achieved grantee-specific clearance standards on windowsills, window troughs (500 μ g/ft 2 and 800 μ g/ft 2 , respectively), and floors (80, 100, or 200 μ g/ft 2 depending on state/local regulations at the dates of clearance in the mid-1990s), with individual grantee success rates ranging from 63 to 100%. Dwellings that failed initial clearance required an average of 1.13 retests to clear. The high level of success at clearance demonstrates that following methods for work site containment, lead hazard control, and cleaning similar to those recommended in the HUD Guidelines for the Evaluation and Control of Lead-Based Paint in Housing is effective. The most common lead hazard control intervention was window abatement accompanied by the repair or abatement of all other deteriorated lead-based paint (56% of dwellings). An additional 5% of dwellings were fully abated, 29% had lower intensity interventions. Interventions including window replacement are recommended to reduce dust lead loading on windowsills and troughs at clearance, but lower level interventions such as full paint stabilization are just as good at reducing floor dust lead loadings. Whatever lead hazard control activities are selected, the condition of the surfaces of interest should be in good condition at clearance.

Evaluation of the HUD Lead Hazard Control Grant Program: Early Overall Findings

This study evaluates the effectiveness of lead hazard control methods used in the Lead Hazard Control (LHC) grant program of U.S. Department of Housing and Urban Development. The LHC Program awards funds to local jurisdictions to address lead hazards in privately owned, low-income dwellings. Grantees in 14 cities, states, or counties collected environmental data in over 2600-treated dwellings making this the largest study of residential lead hazard control ever undertaken. Grantees employed a range of treatments, the most common being replacement of windows and repair of deteriorated lead-based paint. In this paper, dust lead loading levels and blood lead levels of children (6 months-6 years, if present) were observed at four periods of time (preintervention, immediate, and 6- and 12-months postintervention) in 1212 dwellings. Dust lead loading levels were also observed in a subset of these dwellings at 24- and 36-months postintervention. The geometric mean floor and window dust lead loadings declined at least 50 and 88% (P<0.0001), respectively, immediately postintervention. Three years later, floor dust lead loadings remained at or below the immediate postintervention levels. Window dust lead loadings had moderate increases, but remained substantially reduced from preintervention levels and below clearance standards. At 1 year after intervention, geometric mean age-adjusted blood lead levels had declined from 11.0 to 8.2 μg/dL, a 26% decline (P<0.0001). The LHC Program interventions produced blood lead declines similar to or greater than the percentage changes reported in earlier 1-year lead intervention studies.

A Pilot Study Examining Changes in Dust Lead Loading on Walls and Ceilings after Lead Hazard Control Interventions

The U.S. Department of Housing and Urban Development (HUD) guidelines on lead hazard control instruct contractors to clean floors, windows, walls, ceilings, and other horizontal surfaces to remove lead-contaminated dust and debris after lead interventions are conducted. This dust removal activity adds costs to each project. The need to clean floors and windows is well documented in the HUD guidelines. However, there is substantially less documentation to support the recommendation to clean walls and ceilings. We examined whether it is necessary to clean walls and ceilings after lead hazard control (LHC) interventions by comparing dust lead loadings measured on these surfaces before an LHC intervention to dust lead loadings after the intervention. Twenty-two dwelling units undergoing substantial LHC measures consistent with the HUD guidelines were enrolled in the study. There was a significant increase in dust lead loading on walls and ceilings between the pre- and postintervention. The change in wall dust lead loading was substantial and created potentially harmful lead exposures. Although statistically significant, the change in ceiling dust lead loading was minimal and the postintervention dust lead loadings were far below the existing federal floor dust lead clearance standard. These results strongly support the recommendations in the HUD guidelines to clean walls after LHC interventions and do not provide sufficient justification to alter the current recommendation to clean ceilings after lead work.

Lead poisoning of children in Africa, IV: Exposure to dust lead in primary schools in south-central Durban, South Africa

Twenty primary schools in three areas (Merebank, Austerville and Bluff) of south-central Durban, South Africa were studied to determine if dust lead loading (μg/m 2) is high enough to constitute a risk to children. Atmospheric lead fallout rates in the schools varied from 9 to 264 μg/m 2 per day and were higher than the values now being reported in the developed countries. Mean outside dust lead loadings were 425 μg/m 2 in Merebank, 771 μg/m 2 in Austerville and 1174 μg/m 2 in Bluff areas, and 25% of the primary schools were found to have mean outside dust lead loading above 1000 μg/m 2. Mean dust lead loadings inside classrooms were 2–4 times lower than the outside rates, and showed no significant difference among schools in the three areas. Dust lead loadings were correlated with lead concentrations in dust but not with distance from the highway or with atmospheric lead deposition rates. Exposure to dust lead in classrooms and in the school yard is considered to be an important contributor to blood lead levels in, and hence a potential health hazard to, children in many urban areas of the city.

Log-Additive versus Log-Linear Analysis of Lead-Contaminated House Dust and Children's Blood-Lead Levels

The Environmental Protection Agency has been mandated to develop a health-based standard for lead in residential dwellings in the United States. Prior estimates of the relationship between residential dust-lead levels and children's blood-lead concentrations have usually been obtained by using a log-linear regression of blood-lead concentration on levels of lead-contaminated house dust. It remains unknown, however, whether the log-linear model or a frequently cited alternative, the log-additive model, is the preferable regression method for analyzing these data. Secondary analysis of the Lead-in-Dust Study data was undertaken to compare log-additive with log-linear regression analysis for the purpose of developing a health-based dust lead standard. Specifically, we were interested in comparing the log-additive and log-linear analyses in their ability to characterize adequately the relationship of dust-lead loading on various surfaces with blood-lead concentrations among urban children and to develop a predictive model to estimate the risk that a child will develop an elevated blood-lead level on the basis of a known level of dust lead. We used two dust sampling methods, the Baltimore Repair and Maintenance (BRM) vacuum method and the wipe method, to compare the log-linear and log-additive models. The log-linear model was consistently superior to the log-additive model in its ability to explain the variability in the observed blood-lead concentrations of the studied children, for both the wipe sampler and the BRM sampler. In addition, the log-additive model often predicted only a limited increase in the probability of blood-lead concentrations exceeding 10 μg/dl as a result of doubling the dust-lead loading exposure, whereas the log-linear model consistently demonstrated a significant increase in the probability of blood-lead concentrations exceeding 10 μg/dl. BRM lead loading explained additional variability in blood lead above and beyond that explained by wipe loading for both carpeted and uncarpeted floors. In contrast, wipe-lead loading explained significant additional variability after adjustment for BRM loading for both uncarpeted floors and interior window sills. Although BRM loading better predicted children's blood-lead concentrations than did wipe loading, these differences were not statistically significant. We conclude that the log-linear model explained a greater percentage of the variability in blood-lead concentrations than did the log-additive model, indicating that the log-linear model should be the default model of choice for developing a dust-lead standard.

Pilot study of sources of lead exposure in Moscow, Russia

This preliminary investigation of sources of lead exposure in Moscow, Russia, by Russian and US collaborators measured lead in paint, interior dust, and drinking water in seven day-care centres, and in petrol, soil and canned food. Some paint samples exceeded US regulatory standards for lead in paint on surfaces (0.5%). Dust lead loadings were < 1.7 μg cm(-2) and below the guidance levels of the US EPA. Drinking water lead concentrations were at or below the US drinking water standard of 15 μg L(-1). Lead concentrations in petrol from Moscow vehicles and petrol stations were consistent with a regulation banning the sale of leaded petrol within the Moscow City limits. Except for baby food, lead levels were higher in the Russian canned foods (range 6 to 1240 μg kg(-1), dry weight) compared to corresponding US canned foods, with ratios of Russian to US levels of up to 120:1 for evaporated milk. Lead concentrations in soil generally ranged from 500 to 2000 μg g(-1), levels that would trigger hazard reduction measures according to US EPA guidance. These findings, together with the use of lead in petrol outside Moscow, indicate multiple sources of lead exposure in Russia. Priorities for future research are discussed including the establishment of interlaboratory quality control programmes.

A Side-by-Side Comparison of Dust Collection Methods for Sampling Lead-Contaminated House Dust

The Environmental Protection Agency is required to set a standard for lead-contaminated house dust, but whether dust lead loading (μg/ft 2) or concentration (μg/g) is more predictive of children′s blood lead levels, which dust collection method should be used, and which surfaces should be sampled are unknown. Using a random sample of sequential births, we enrolled 205 urban children, 12 to 30 months of age, who had lived in the same house since at least 6 months of age. Samples of dust were obtained from predetermined surfaces in each child′s residence using a wipe method and two vacuum methods, the Baltimore repair and maintenance method (BRM) and the dust vacuum method (DVM). Other potential sources of environmental exposure also were analyzed for lead, including soil, water, and paint. In general, dust lead loading is more predictive of children′s blood lead levels than is dust lead concentration. Dust lead loading as measured with the BRM sampler explained more of the variation in children′s blood lead levels than did wipe loading and DVM loading (13.7, 10.1, and 5.9%, respectively, adjusted for other significant predictors). The partial correlation between BRM lead loading and children′s blood lead was significantly different than that for DVM lead loading, but it was not significantly different than that for wipe lead loading. Of the four surfaces measured, noncarpeted floors and interior window sills or wells were significantly associated with children′s blood lead levels in multiple regression models. These data indicate that dust lead loading is more predictive of children′s blood lead levels than is dust lead concentration and that, to determine if a housing unit is safe for children, noncarpeted floors and interior window sills or window wells should be measured using either the BRM or wipe sampling method.

The Longer-Term Effectiveness of Residential Lead Paint Abatement

Residential lead-based paint and settled dust are important sources of lead exposure in U.S. children. Scant information exists on the long-term effectiveness of alternative lead abatement practices. In this extended (1.5-3.5 years) follow-up study of comprehensive abatement, 179 wipe dust samples were collected in 13 occupied dwellings for which pre-and immediately postabatement (clearance) dust lead data were available. Dust lead loadings (mg/m 2) 1.5 to 3.5 years postabatement were 16, 10, and 4% of preabatement levels for floors, window sills, and window wells, respectively. Furthermore, 78% of readings remained within Maryland′s interim clearance standards, indicating that sustained reductions of dust lead hazards were achieved in comprehensively abated dwellings located in older unabated housing areas.