A study of urban housing demolitions as sources of lead in ambient dust: demolition practices and exterior dust fall

Demolition of older housing for urban redevelopment purposes benefits communities by removing housing with lead paint and dust hazards and by creating spaces for lead paint-free housing and other community resources. This study was conducted to assess changes, if any, in ambient dust lead levels associated with demolition of blocks of older lead-containing row houses in Baltimore, Maryland (USA). In this article we present results based on dust-fall samples collected from fixed locations within 10 m of three demolition sites. In subsequent reports we will describe dust lead changes on streets, sidewalks, and residential floors within 100 m of the demolition sites. Geometric mean (GM) lead dust-fall rate increased by > 40-fold during demolition to 410 micro g Pb/m2/hr (2,700 micro g Pb/m2 per typical work day) and by > 6-fold during debris removal to 61 micro g Pb/m2/hr (440 micro g Pb/m2 per typical work day). Lead concentrations in dust fall also increased during demolition (GM, 2,600 mg/kg) and debris removal (GM, 1,500 mg/kg) compared with baseline (GM, 950 mg/kg). In the absence of dust-fall standards, the results were compared with the U.S. Environmental Protection Agency's (U.S. EPA's) dust-lead surface loading standard for interior residential floors (40 micro g/ft2, equivalent to 431 micro g/m2); daily lead dust fall during demolition exceeded the U.S. EPA floor standard by 6-fold on average and as much as 81-fold on an individual sample basis. Dust fall is of public health concern because it settles on surfaces and becomes a pathway of ambient lead exposure and a potential pathway of residential exposure via tracking and blowing of exterior dust. The findings highlight the need to minimize demolition lead deposition and to educate urban planners, contractors, health agencies, and the public about lead and other community concerns so that society can maximize the benefits of future demolition activities nationwide.     

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 microg/ft2 on floors and 182 to 88 microg/ft2 on sills; for window abatement plus other treatments, 27-8 microg/ft2 on floors and 570-124 microg/ft2 on sills). Full abatement reduced windowsill and floor loadings from baseline to 12 months postintervention [95-6 microg/ft2 on floors and 518-30 microg/ft2 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.     

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 microg/ft2, 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.     

A multihazard, multistrategy approach to home remediation: results of a pilot study

Many residential hazards are disproportionately concentrated in older, urban dwellings and share common underlying causes, such as uncorrected moisture problems and inadequate maintenance and cleaning. Comprehensive and affordable approaches to remediation are needed, but the feasibility and efficacy of such approaches has not been well documented. To address this gap, a multihazard, multimethod intervention, addressing deteriorated lead-based paint and lead dust, vermin, mold, and safety hazards was pilot-tested in a sample of 70 pre-1940 dwellings. Dwellings received paint stabilization, dust lead cleaning, integrated pest management (IPM), mold cleaning, and safety devices, as needed. The median remediation cost for labor and materials was 864.66 dollars (range: 120.00-5235.33 dollars) per dwelling. Environmental conditions were evaluated prior to, immediately following, and an average of 5 months after remediation. Between the baseline and 5-month follow-up periods, significant reductions were achieved in the number of dwellings with multiple (i.e., three or four) problems (75% vs. 23%, P<0.0001); high levels of dust lead on floors and window sills (67% and 46% declines, P<0.01); evidence of cockroaches or rodents (43% and 36% declines, P<0.01); and fire, electrical and/or fall hazards (between 67% and 88% declines, P<0.01). Significant reductions were also observed in the geometric mean (GM) dust lead levels on floors and window sills (13.3 vs. 5.0 microg/ft2 and 210.6 vs. 81.0 microg/ft2, respectively, P<0.0001) and Blatella germanica (Blag1) levels among dwellings with elevated baseline levels (7.7 vs. 0.09 U/g, P<0.0001). Reductions in mold dust levels were of borderline statistical significance (50% decline, P=0.07). The greatest declines in dust lead and Blag1 levels occurred in dwellings having the highest baseline levels and, for Blag1, in dwellings in which occupants attended training sessions. These results indicate that a comprehensive approach to hazard remediation can be highly effective and cost efficient and that overall improvements can be maintained. Further research is needed to clarify the most effective sampling strategies, educational and behavioral interventions, and optimal intervention frequency.     

An evaluation of one-time professional cleaning in homes with lead-based paint hazards

A key challenge in reducing the burden of lead poisoning is to identify cost-effective interventions that minimize lead-based paint hazards. One-time professional cleaning of lead-contaminated dust and debris was conducted in 37 housing units with deteriorated lead-based paint and dust lead hazards. These study units are a subset of a larger cohort of the nearly 3500 housing units enrolled in the Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program. Dust lead loading measurements were taken prior to cleaning, immediately after cleaning (i.e., clearance), and six months, one, two, and three years post-intervention. The cleaning intervention significantly reduced dust lead loadings on floors, windowsills, and window troughs immediately following the work. However, these reductions did not persist at six months and one year post-intervention. Six months and one year post-intervention dust lead loadings are not significantly different from the pre-intervention loadings on either bare floors or windowsills. Although window trough lead loadings declined over 50 percent from pre-intervention to one year post-intervention, the loadings rebounded markedly from the geometric mean at clearance of 101 microgram/ft(2) to 5500 microgram/ft(2) at 6 months and 5790 microgram/ft(2) at one-year post-intervention. These results demonstrate that a single professional cleaning of dust and debris without addressing potential sources of lead dust (such as deteriorated lead-based paint) or repeating the cleaning are unlikely to result in significant and sustained reductions in dust lead loadings. More extensive interventions that address deteriorated lead-based paint, although more expensive, are likely to provide longer term reductions in dust lead loadings. Cleaning strategies, however, may be useful in emergency situations to reduce lead dust hazards when paint repair and other lead hazard control activities cannot be done immediately.     

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 micro g/ft(2); 130 versus 28 micro g/ft(2)) while 1-year postintervention common area dust lead loadings are four to six times that of dwelling dust lead loadings (41 versus 11 micro g/ft(2); 44 versus 8 micro g/ft(2)). Windowsill dust lead loadings in common areas were twice the loadings in dwelling units at preintervention and 1-year postintervention (756 versus 383 mu g/ft(2); 154 versus 68 micro g/ft(2)). 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.     

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 microg/ft2 and 800 microg/ft2, respectively), and floors (80, 100, or 200 microg/ft2 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.     

The influence of exterior dust and soil lead on interior dust lead levels in housing that had undergone lead-based paint hazard control

To aid in understanding the contribution of exterior dust/soil lead to postintervention interior dust lead, a subset of housing from the HUD Lead-Based Paint Hazard Control Grant Program Evaluation was selected for study. Housing from 12 state and local governments was included. Exterior entry and street dust samples were obtained by a vacuum method, and soil samples were building perimeter core composites. Interior dust wipe lead data (microg/ft(2)) and paint lead data (mg/cm(2)) were also available for each of the dwelling units and included in the modeling. Results from 541 dwelling units revealed a wide range of exterior dust and soil lead levels, within and between grantees. Minimum and maximum geometric mean lead levels, by grantee, were 126 and 14400 microg/ft(2) for exterior entry dust; 325 and 4610 microg/ft(2) for street dust; and, for soil concentration, 383 and 2640 ppm. Geometric mean exterior entry dust lead concentration (1641 ppm) was almost four times as high as street dust lead concentration (431 ppm), suggesting that lead dust near housing was often a source of street dust lead. Geometric mean exterior entry dust lead loading was more than four times as high as window trough dust lead loading and more than an order of magnitude higher than interior entry dust lead loading. Statistical modeling revealed pathways from exterior entry dust lead loading to loadings on interior entryway floors, other interior floors, and windowsills. Paint lead was found to influence exterior entry dust lead. Results of this study show that housing where soil lead hazard control activities had been performed had lower postintervention exterior entry, interior entry floor, windowsills, and other floor dust loading levels. Soil was not present for almost half the buildings. Statistical analysis revealed that exterior strategy influenced soil lead concentration, and soil lead concentration influenced street dust lead loading. This study represents one of the few where an impact of soil treatments on dust lead levels within the housing has been documented and may represent the first where an impact on exterior entry dust lead has been found. The inclusion of measures to mitigate the role of exterior sources in lead hazard control programs needs consideration.     

Reliability of spot test kits for detecting lead in household dust

There has been a long-standing need for a technique that can provide fast, accurate and precise results regarding the presence of hazardous levels of lead in settled house dust. Several home testing kits are now available. One kit manufactured by Hybrivet (LeadCheck Swabs) is advertised as able to detect lead dust levels that exceed the US Environmental Protection Agency's dust lead standard for floors (40 microg/ft(2)). The purpose of the study was to determine the ability of LeadCheck Swabs to instantly detect lead in dust above EPA's hazard standard. A trained risk assessor collected 200 LeadCheck Swab samples side-by-side with standard dust wipe samples. The result of the LeadCheck Swab (positive (pink or red) or negative (yellow to brown)) was compared with the laboratory results for the corresponding dust wipe (over or under 40 microg/ft(2)). The LeadCheck Swabs produced a false negative rate of 64% (95% confidence interval: 55%, 72%). The likelihood of a swab producing a false negative depended on substrate (painted or non-painted) and surface type (floor or sill). Changing the interpretation rule by classifying all swab colors except yellow as positive yielded lower false negative rates under some test conditions, but still produced high error rates. LeadCheck Swabs do not reliably detect levels of lead in dust above 40 microg/ft(2) using published methods under field conditions. Further research into alternate methodologies and interpretation guidance is needed to determine whether the swabs can be appropriately used by consumers and others to test homes for lead dust hazards.     

Assessment of cleaning to control lead dust in homes of children with moderate lead poisoning: treatment of lead-exposed children trial

In this article we describe the assessment and control of lead dust exposure in the Treatment of Lead-exposed Children (TLC) Trial, a clinical trial of the effects of oral chelation on developmental end points in urban children with moderately elevated blood lead levels. To reduce potential lead exposure from settled dust or deteriorated paint during the drug treatment phase of the trial, the homes of 765 (98%) of the randomized children (both active and placebo drug treatment groups) were professionally cleaned. Lead dust measurements were made in a sample of 213 homes before and after cleaning. Geometric mean dust lead loadings before cleaning were 43, 29, 308, and 707 micro g/ft2 in the kitchen floor, playroom floor, playroom windowsill, and playroom window well samples respectively. Following cleaning, floor dust lead loadings were reduced on average 32% for paired floor samples (p < 0.0001), 66% for windowsills (p < 0.0001), and 93% for window wells (p < 0.0001). Cleaning was most effective for 146 homes with precleaning dust lead levels above the recommended clearance levels, with average reductions of 44%, 74%, and 93% for floors (p < 0.0001), windowsills (p < 0.0001), and window wells (p < 0.0001), respectively. Despite these substantial reductions in dust lead loadings, a single professional cleaning did not reduce the lead loadings of all dust samples to levels below current federal standards for lead in residential dust. Attainment of dust levels below current standards will require more intensive cleaning and lead hazard reduction strategies.     

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 microg/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.     

Exposures to lead-based paint dust in an inner-city high school

In response to concerns about lead-based paint (LBP) in an 85-year old high school, an evaluation was conducted to determine whether a lead exposure hazard existed for adult school staff. Deteriorating LBP was present on walls and ceilings throughout the school. At the time of the evaluation, abatement of LBP had been completed in approximately one-third of the school. One-hundred eighteen wipe samples for lead dust were collected from floors, teachers' desks, and interior window sills. Areas selected for sampling were based on the work location of the 45 participants providing blood for lead analysis. Wipe samples from hands were collected from all participants. The geometric means (GMs) for lead dust loadings on sills in unabated rooms (n = 23) and abated rooms (n = 16) were 342 and 102 micrograms/ft2, respectively. Nine sills in unabated rooms and one sill in an abated room exceeded the Housing and Urban Development (HUD) guidelines (500 micrograms/ft2 lead) for residential housing following abatement activity. GMs for lead loadings on floors in unabated rooms (n = 26) and abated rooms (n = 14) were 136 and 70 micrograms/ft2 lead, respectively. Seventeen floor samples from unabated rooms and 3 samples from abated rooms exceeded HUD guidelines (100 micrograms/ft2 lead). The GM blood lead level (BLL) was 2.2 micrograms/dL (range: 0.6-5.6 micrograms/dL), similar to that of the general U.S. population. Despite peeling LBP and significant lead dust loadings, a hazard from LBP was not found for staff at the school. There were no relationships between surface lead and hand lead, BLL and abatement status of assigned work area, or BLL and hand lead.     

中国12个城市中心城区步行道设置情况调查

目的 了解中国12个城市中心城区步行道配备、维护情况及其与城市经济水平、区域居住密度和街道繁荣程度间的关联。方法 以北京、天津、上海、青岛、杭州、绍兴、苏州、南通、镇江、成都、西宁、哈尔滨共12个城市的54个中心城区333个调查点内所有的道路为调查对象,于2012年采用观察法调查道路两侧步行道的配备及维护情况。结果 共有4 255条路段纳入分析,其中有71.1%的路段配有步行道。12个城市中配备步行道的路段比例最高的城市为青岛（91.9%）和哈尔滨（90.6%）,最低的是苏州（48.6%）和绍兴（52.6%）。12个城市在步行道配备及维护各方面差异均有统计学意义,高经济水平城市的步行道配备和路面维护情况较好、阻碍较少,但步行道隔离连续性较差、划线停车较多。相比低居住密度区域,高居住密度区域的步行道隔离连续性较差、步行道较窄,同时划线停车和阻碍较多。道路繁荣度越高,步行道配备和步行道宽度的情况越好,但隔离连续性、路面维护状况越差,划线停车和阻碍也更多。结论 12个城市步行道配备及维护状况差异具有统计学意义,12个城市步行道的配备情况还存在进一步改善的空间。建议在进行城市道路规划时,结合当地人口密度和实际的交通需求,合理配备步行道;同时加强城市管理,减少步行道上的阻碍。     

Household dust metal levels in the Sydney metropolitan area

Household dust was collected from 82 residential homes within the Sydney metropolitan area. The geometric mean concentrations of metals in the household dust were Cd, 1.9 microg/g; Cr, 64.3 microg/g; Cu, 103 microg/g; Fe, 2740 microg/g; Mn, 54 microg/g; Ni, 15.6 microg/g; Pb, 85.2 microg/g; and Zn, 437 microg/g. Differences in household income level, dwelling type, or the number of occupants were not statistically significant for the majority of metals. The exceptions were higher amounts of Zn (P=0.033) and Fe (P=0.047) found in households with only 1-2 residents compared to those with 3-4 or >4 residents, and slightly higher Mn levels (P=0.033) were found in low-income households (AUD 0-30,000 dollars/year). Region was highly significant for Pb levels in Sydney but not significant for other metals. Large variations in Pb levels were found in household dust (16-16,600 microg/g), with the inner-west region associated with significantly higher Pb levels (P<0.001). Comparisons with a study from a decade earlier have revealed that the household dust Pb levels have remained constant despite substantial improvements in air quality in the inner-west area of Sydney. New epidemiological studies are required to determine whether Pb blood levels have also remained unchanged and whether accumulated Pb in household dust represents a significant health risk to children in this region.     

Maternal and umbilical cord blood levels of mercury, lead, cadmium, and essential trace elements in Arctic Canada

Maternal and umbilical cord blood levels of mercury (Hg), lead (Pb), cadmium (Cd), and the trace elements copper (Cu), zinc (Zn), and selenium (Se) are reported for Inuit, Dene/Métis, Caucasian, and Other nonaboriginal participants from Arctic Canada. This is the first human tissue monitoring program covering the entire Northwest Territories and Nunavut for multiple contaminants and establishes a baseline upon which future comparisons can be made. Results for chlorinated organic pesticides and PCBs for these participants have been reported elsewhere. Between May 1994 and June 1999, 523 women volunteered to participate by giving their written informed consent, resulting in the collection of 386 maternal blood samples, 407 cord samples, and 351 cord:maternal paired samples. Geometric mean (GM) maternal total mercury (THg) concentrations ranged from 0.87 microg/L (SD = 1.95) in the Caucasian group of participants (n = 134) to 3.51 microg/L (SD = 8.30) in the Inuit group (n = 146). The GM of the Inuit group was 2.6-fold higher than that of the Dene/Métis group (1.35 microg/L, SD = 1.60, n = 92) and significantly higher than those of all other groups (P<0.0001). Of Inuit women participants, 3% (n = 4) were within Health Canada's level of concern range (20-99 microg/L) for methylmercury (MeHg) exposure. Of Inuit and Dene/Métis cord samples, 56% (n = 95) and 5% (n = 4), respectively, exceeded 5.8 microg/L MeHg, the revised US Environmental Protection Agency lower benchmark dose. GM maternal Pb was significantly higher in Dene/Métis (30.9 microg/L or 3.1 microg/dL; SD = 29.1 microg/L) and Inuit (31.6 microg/L, SD = 38.3) participants compared with the Caucasian group (20.6 microg/L, SD = 17.9) (P < 0.0001). Half of all participants were smokers. GM blood Cd in moderate smokers (1-8 cigarettes/day) and in heavy smokers (> 8 cigarettes/day) was 7.4-fold higher and 12.5-fold higher, respectively, than in nonsmokers. The high percentage of smokers among Inuit (77%) and Dene/Métis (48%) participants highlights the need for ongoing public health action directed at tobacco prevention, reduction, and cessation for women of reproductive age. Pb and THg were detected in more than 95% of all cord blood samples, with GMs of 21 microg/L and 2.7 microg/L, respectively, and Cd was detected in 26% of all cord samples, with a GM of 0.08 microg/L. Cord:maternal ratios from paired samples ranged from 0.44 to 4.5 for THg, from 0.5 to 10.3 for MeHg, and 0.1 to 9.0 for Pb. On average, levels of THg, MeHg, and Zn were significantly higher in cord blood than in maternal blood (P < 0.0001), whereas maternal Cd, Pb, Se, and Cu levels were significantly higher than those in cord blood (P < 0.0001). There was no significant relationship between methylmercury and selenium for the range of MeHg exposures in this study. Ongoing monitoring of populations at risk and traditional food species, as well as continued international efforts to reduce anthropogenic sources of mercury, are recommended.     

Resident cleanup activities, characteristics of flood-damaged homes and airborne microbial concentrations in New Orleans, Louisiana, October 2005

BACKGROUND: Flooding in the greater New Orleans (GNO) area after the hurricanes caused extensive mold growth in homes resulting in public health concerns. OBJECTIVES: We conducted an environmental assessment of homes to determine the extent and type of microbial growth. METHODS: We randomly selected 112 homes, stratified by water damage, and then visually assessed mold growth. Air samples from a subset of 20 homes were analyzed for culturable fungi, fungal spores, and markers of mold ((1-->3, 1-->6)-beta-D-glucans) and bacteria (endotoxin). RESULTS: Visible mold growth occurred in 49 (44%) homes; 18 (16%) homes had >50% mold coverage. Flood levels were >6 ft at 20 (19%), 3-6 ft at 20 (19%), and <3 ft at 28 (26%) homes out of 107; no flooding at 39 (36%) homes. The residents spent an average of 18 h (range: 1-84) doing heavy cleaning and of those, 22 (38%) reported using an N-95 or other respirator. Visible mold growth was significantly associated with flood height 3 ft and the predominant fungi indoors were Aspergillus and Penicillium species, which were in higher concentrations in homes with a flood level 3 ft. Geometric mean (GM) levels of endotoxin were as high as 40.2 EU/m(3), while GM glucan levels were as high as 3.5 microg/m(3) even when flooding was 3 ft. CONCLUSIONS: Based on our observations of visible mold, we estimated that elevated mold growth was present in 194,000 (44%) homes in the GNO area and 70,000 (16%) homes had heavy mold growth. Concentrations of endotoxin and glucans exceeded those previously associated with health effects. With such high levels of microbial growth following flooding, potentially harmful inhalation exposures can be present for persons entering or cleaning affected homes. Persons exposed to water-damaged homes should follow the CDC recommendations developed following the 2005 hurricanes for appropriate respiratory precautions.     

High lead exposures resulting from pottery production in a village in Michoacán State, Mexico.

This paper reports findings from a screening study conducted to examine potential lead (Pb) exposures in residents of a Mexican village where Pb oxide continues to be used in ceramic pottery production. Extremely high Pb concentrations were measured in personal and indoor air samples, household surface dust samples, and household soil samples. Personal air Pb concentrations for workers performing pottery firing and glazing were up to 454 microg/m3. Results from indoor air samples indicate that airborne Pb concentrations were lower during nonglazing period compared to the glazing period. Soil Pb concentrations measured in 17 homes ranged from 0.39 to 19.8 mg/g. Dust Pb loading on surfaces of household items, hands, and clothes of a worker ranged from 172 to 33,060 microg/ft2. Pb content as high as 2.4 microg/g was found in a bean stew cooked in a pot made in the village. Based on these Pb concentrations measured in multiple media and data adapted for exposure contact rates, we have made rough estimates of Pb exposures via inhalation, soil/dust ingestion, and food ingestion. Estimated total daily Pb intake, on average, is 4.0 mg for adults and 3.4 mg for children living in the village. In the total daily intake, a greatest fraction may be contributed by food ingestion and another significant fraction may come from soil/dust ingestion for the children. Although the sample size is small, these measurements indicate a very significant public health problem for the village residents and a large number of other similar communities in Mexico. (It was estimated that there are approximately 1.5 million glaze potters.) The Pb exposure is implicated in a number of pervasive health problems in the region, and is the cause for national and international attention. Several recommended solutions to this problem range from personal protection and behavioral changes to introduction of alternative glazes.     

Exposure to inhalable dust, wheat flour and alpha-amylase allergens in industrial and traditional bakeries

This study was designed to characterize exposure to inhalable dust, wheat flour and alpha-amylase allergens in industrial and traditional bakeries. The study included 70 bakeries from the northern part of Belgium. Based on the degree of automation and a clear division of individual job tasks, four bakeries were identified as industrial and the remaining 66 were identified as traditional ones. Personal, as well as stationary, samples of inhalable dust were collected during full shift periods, usually 5-7 h. The portable pumps aspirated 2 l/min through Teflon personal dust samplers (Millipore, pore size 1.0 microm) mounted in PAS-6 sampling heads. In the collected samples the inhalable dust, wheat flour and alpha-amylase allergens were determined. Wheat flour allergens were measured using enzyme-linked immunosorbent assay inhibition and an antiwheat IgG4 serum pool. The alpha-amylase allergens were measured using a sandwich enzyme immunoassay with affinity-purified polyclonal rabbit IgG antibodies. In total, 440 samples (300 personal and 140 stationary) were processed. The highest inhalable dust exposure was observed in traditional bakeries among bread [geometric mean (GM) 2.10 mg/m3] and bread and pastry workers (GM 1.80 mg/m3). In industrial bakeries the highest dust exposure was measured in bread-producing workers (GM 1.06 mg/m3). Similar relations were observed for wheat flour and alpha-amylase allergens. Bread baking workers in traditional bakeries had the highest exposure to both allergens (wheat flour GM 22.33 microg/m(3), alpha-amylase GM 0.61 ng/m3). The exposure to wheat flour and alpha-amylase allergens in industrial bakeries was higher in bread baking workers (wheat flour GM 6.15 microg/m3, alpha-amylase GM 0.47 ng/m3) than in bread packing workers (wheat flour GM 2.79 microg/m3, alpha-amylase GM 0.15 ng/m3). The data presented suggest that, on average, exposure in the Belgium bakeries studied-industrial as well as traditional-is lower than or similar to bakeries in The Netherlands, Canada, Sweden, the United Kingdom and Finland. Furthermore, the exposure levels in traditional bakeries seem to be higher than in industrial bakeries.     

Vitamin D receptor Fok1 polymorphism and blood lead concentration in children

Variation in blood lead concentration is caused by a complex interaction of environmental, social, nutritional, and genetic factors. We evaluated the association between blood lead concentration and a vitamin D receptor (VDR) gene polymorphism. Environmental samples and blood were analyzed for lead, nutritional and behavioral factors were assessed, and VDR -Fok1 genotype was determined in 245 children. We found a significant interaction between floor dust lead and genotype on blood lead concentration. For every 1 microg/ft(2) increase in floor dust, children with VDR -FF genotype had a 1.1% increase in blood lead [95% confidence interval (CI), 0.69-1.5], VDR -Ff, 0.53% increase (95% CI, 0.1-0.92), and VDR -ff, 3.8% increase (95% CI, 1.2-6.3); however, at floor dust levels < 10 microg/ft(2), children with VDR -ff had the lowest blood lead concentrations. These data suggest that VDR -Fok1 is an effect modifier of the relationship of floor dust lead exposure and blood lead concentration.     

Changes in manganese and lead in the environment and young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl in gasoline--preliminary results

A 4-year longitudinal study is being conducted to evaluate potential changes to the environment and exposure of young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl (MMT) into Australia in 2001. The cohort consists of 57 females and 56 males, with an age range of 0.29-3.9 years. Samples are collected every 6 months from children in residences located at varying distances from major traffic thoroughfares in Sydney. Environmental samples include air, house, and daycare center dustfall, soil, dust sweepings, and gasoline; samples from the children include blood, urine, handwipes prior to and after playing outdoors, and a 6-day duplicate diet. All samples are analyzed for a suite of 20 elements using inductively coupled plasma methods. Results are presented for the first three 6-month sampling periods for lead (Pb) and manganese (Mn). For dustfall accumulation, expressed as metal concentration/m2/30 days, there was no significant difference between homes and daycare centers for either Pb or Mn, no significant change over the three sampling periods (time) for Pb or Mn, and a positive relationship between "traffic exposure" (traffic volume and proximity to the road) and Pb but not Mn. Lead concentrations in soil was a significant predictor for Pb in the house dustfall. For handwipes, the concentrations of Pb and Mn in wipes taken from children after playing outdoors was usually significantly greater than those for wipes taken prior to playing. There was no significant association between the concentrations of either Pb or Mn in handwipes and traffic exposure, and there was no significant association between Pb concentrations in the handwipes and gender, although the latter showed a marginally significant association for Mn (P = 0.053). Age was related to Pb level in the handwipes, with older subjects having higher Pb levels, and there were significant decreases in Pb and Mn concentrations over time. Dustfall accumulation was a significant predictor for Pb in the handwipes, and dust sweepings were a significant predictor of Mn in handwipes. Blood lead (PbB) concentrations ranged from 0.6 to 19 microg/dL (GM 2.6) (n = 269), and manganese in blood (MnB) ranged from 1.8 to 45 microg/L (GM 11.6) (n = 254). There was no significant difference between females and males for either mean PbB or MnB; over time there was a significant decline in PbB but no significant change in MnB. The only significant predictor for PbB was dustfall accumulation, although dietary intake may also be important, and the only significant predictor for MnB was Mn in handwipes prior to playing. At this early stage of the investigation we have not been able to detect any increases in Mn in these environmental samples or blood samples potentially associated with the use of MMT; in fact the Mn levels in handwipes declined over time.