The effect of dust lead control on blood lead in toddlers: a randomized trial

Effectiveness of educational interventions for the prevention of lead poisoning in children: a systematic review

INTRODUCTION

Childhood exposure to lead has severe health consequences including long-term physical, behavioral, and learning problems. Lead poisoning often occurs in the home and persists as a form of environmental injustice, disparately impacting certain children based on factors such as socioeconomic status, immigration status, and race. Because abatement is costly, many prevention programs rely on educational interventions. We conducted a systematic review to assess the effectiveness of educational interventions on reducing blood lead levels (BLL) in children.

CONTENT

Following PRISMA-P guidelines, a librarian-guided search strategy incorporated database-specific subject headings and keywords related to lead poisoning and education, and encompassed four databases: Ovid MEDLINE, Scopus, Web of Science Core Collection and CINAHL. Two reviewers screened the results for those that met inclusion criteria (original research, study population of children under 18 years, inclusion of an educational intervention, outcome of BLL).

SUMMARY AND OUTLOOK

We screened the titles of 2,062 non-duplicate studies, the abstracts of 78 studies, and full texts of 23 articles, resulting in 17 articles that met eligibility criteria. Thirteen studies used multi-pronged interventions, which precluded comprehensive assessment of the effectiveness of the educational component. Interventions that had success in lowering BLL included some notable elements: longevity of intervention, consideration of culture and ethnicity; use of a community or home-based approach; and provision of supplies or assistance with cleaning. Of the four of studies that used solely educational interventions, three were successful in reducing BLL. Among the 12 studies that used a control group, six found their interventions to be successful in reducing BLL. This review found that educational interventions, either alone or as part of a multi-pronged approach, do not consistently reduce BLL in children. However, educational interventions may decrease severity of lead poisoning in children when more robust interventions are not feasible.

Knowledge, confidence, and reported behaviors that promote safe water drinking among women of reproductive age

Introduction

Drinking lead contaminated water during pregnancy is associated with infant mortality. All women of reproductive age are advised by health agencies to adhere to healthy behaviors due to the chance of unintended pregnancy. Our objectives are to understand knowledge, confidence, and reported behaviors that promote safe water drinking and prevent lead exposure among women of reproductive age.

Methods

A survey among females of reproductive age from the University of Michigan - Flint was administered. A total of 83 females who wished to become pregnant one day participated.

Results

Low levels of knowledge, confidence, and reported preventative health behaviors related to safe water drinking and lead exposure prevention existed. Specifically, 71.1% of respondents (59 of 83) were not at all or were somewhat confident in their ability to choose an appropriate lead water filter. Most participants rated their knowledge on how to decrease exposure to lead during pregnancy as poor/fair. No statistically significant differences were detected between respondents residing inside and outside of the city of Flint, Michigan for most variables assessed.

Conclusion

While the small sample size is a limitation, the study adds to an area of scarce research. Despite widespread media attention and resources directed toward reducing the negative health effects of lead exposure following the Flint Water Crisis, significant gaps in knowledge related to safe water drinking remain. Interventions are needed to increase knowledge, confidence, and healthy behaviors that promote safe water drinking among women of reproductive age.

Predictive modeling of indoor dust lead concentrations: Sources, risks, and benefits of intervention

Lead (Pb) contamination continues to contribute to world-wide morbidity in all countries, particularly low- and middle-income countries. Despite its continued widespread adverse effects on global populations, particularly children, accurate prediction of elevated household dust Pb and the potential implications of simple, low-cost household interventions at national and global scales have been lacking. A global dataset (∼40 countries, n = 1951) of community sourced household dust samples were used to predict whether indoor dust was elevated in Pb, expanding on recent work in the United States (U.S.). Binned housing age category alone was a significant (p < 0.01) predictor of elevated dust Pb, but only generated effective predictive accuracy for England and Australia (sensitivity of ∼80%), similar to previous results in the U.S. This likely reflects comparable Pb pollution legacies between these three countries, particularly with residential Pb paint. The heterogeneity associated with Pb pollution at a global scale complicates the predictive accuracy of our model, which is lower for countries outside England, the U.S., and Australia. This is likely due to differing environmental Pb regulations, sources, and the paucity of dust samples available outside of these three countries. In England, the U.S., and Australia, simple, low-cost household intervention strategies such as vacuuming and wet mopping could conservatively save 70 billion USD within a four-year period based on our model. Globally, up to 1.68 trillion USD could be saved with improved predictive modeling and primary intervention to reduce harmful exposure to Pb dust sources.

Using Community Science to Better Understand Lead Exposure Risks

Lead (Pb) is a neurotoxicant that particularly harms young children. Urban environments are often plagued with elevated Pb in soils and dusts, posing a health exposure risk from inhalation and ingestion of these contaminated media. Thus, a better understanding of where to prioritize risk screening and intervention is paramount from a public health perspective. We have synthesized a large national data set of Pb concentrations in household dusts from across the United States (U.S.), part of a community science initiative called "DustSafe." Using these results, we have developed a straightforward logistic regression model that correctly predicts whether Pb is elevated (>80 ppm) or low (<80 ppm) in household dusts 75% of the time. Additionally, our model estimated 18% false negatives for elevated Pb, displaying that there was a low probability of elevated Pb in homes being misclassified. Our model uses only variables of approximate housing age and whether there is peeling paint in the interior of the home, illustrating how a simple and successful Pb predictive model can be generated if researchers ask the right screening questions. Scanning electron microscopy supports a common presence of Pb paint in several dust samples with elevated bulk Pb concentrations, which explains the predictive power of housing age and peeling paint in the model. This model was also implemented into an interactive mobile app that aims to increase community-wide participation with Pb household screening. The app will hopefully provide greater awareness of Pb risks and a highly efficient way to begin mitigation.

A Children's Health Perspective on Nano- and Microplastics

BACKGROUND

Pregnancy, infancy, and childhood are sensitive windows for environmental exposures. Yet the health effects of exposure to nano- and microplastics (NMPs) remain largely uninvestigated or unknown. Although plastic chemicals are a well-established research topic, the impacts of plastic particles are unexplored, especially with regard to early life exposures.

OBJECTIVES

This commentary aims to summarize the knowns and unknowns around child- and pregnancy-relevant exposures to NMPs via inhalation, placental transfer, ingestion and breastmilk, and dermal absorption.

METHODS

A comprehensive literature search to map the state of the science on NMPs found 37 primary research articles on the health relevance of NMPs during early life and revealed major knowledge gaps in the field. We discuss opportunities and challenges for quantifying child-specific exposures (e.g., NMPs in breastmilk or infant formula) and health effects, in light of global inequalities in baby bottle use, consumption of packaged foods, air pollution, hazardous plastic disposal, and regulatory safeguards. We also summarize research needs for linking child health and NMP exposures and address the unknowns in the context of public health action.

DISCUSSION

Few studies have addressed child-specific sources of exposure, and exposure estimates currently rely on generic assumptions rather than empirical measurements. Furthermore, toxicological research on NMPs has not specifically focused on child health, yet children's immature defense mechanisms make them particularly vulnerable. Apart from few studies investigating the placental transfer of NMPs, the physicochemical properties (e.g., polymer, size, shape, charge) driving the absorption, biodistribution, and elimination in early life have yet to be benchmarked. Accordingly, the evidence base regarding the potential health impacts of NMPs in early life remains sparse. Based on the evidence to date, we provide recommendations to fill research gaps, stimulate policymakers and industry to address the safety of NMPs, and point to opportunities for families to reduce early life exposures to plastic. https://doi.org/10.1289/EHP9086.

Reduction in Blood Lead Concentration in Children across the Republic of Georgia following Interventions to Address Widespread Exceedance of Reference Value in 2019

In recent years, reports of lead contamination have dramatically increased in Georgia. Given concerns about the exposure of children to lead (Pb), the National Multiple Indicator Cluster Survey (MICS-2018) included a blood sampling component. The results showed that 41% of the children that participated had blood Pb levels (BLL) ≥ 5 µg/dL and that BLL in children living in Western Georgia were higher than those in Eastern regions. In response to these findings, NCDC implemented written and verbal advice to the families of children who participated in the MICS-2018 on how to reduce Pb exposure. From August 2019 onwards, the state program of clinical follow-up was implemented. The design of this study was a longitudinal study. The intervention of interest was the public health advice and medical follow-up, and the outcome was defined as the difference in BLL between the MICS-2018 survey and the state program follow-up. We observed a significant overall reduction in median BLL between MICS-2018 and state program follow-up in both August 2019 and the latest results (until December 2019). However, we did not observe any significant further reduction between August and the most recent BLL results. In the Georgian setting, written and verbal communication targeting individual households, alongside home visits to the most exposed, effectively reduced BLL in children.

Household interventions for secondary prevention of domestic lead exposure in children

BACKGROUND

Lead exposure is a serious health hazard, especially for children. It is associated with physical, cognitive and neurobehavioural impairment in children. There are many potential sources of lead in the environment, therefore trials have tested many household interventions to prevent or reduce lead exposure. This is an update of a previously published review.

OBJECTIVES

To assess the effects of household interventions intended to prevent or reduce further lead exposure in children on improvements in cognitive and neurobehavioural development, reductions in blood lead levels and reductions in household dust lead levels.

SEARCH METHODS

In March 2020, we updated our searches of CENTRAL, MEDLINE, Embase, 10 other databases and ClinicalTrials.gov. We also searched Google Scholar, checked the reference lists of relevant studies and contacted experts to identify unpublished studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of household educational or environmental interventions, or combinations of interventions to prevent lead exposure in children (from birth to 18 years of age), where investigators reported at least one standardised outcome measure.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 17 studies (three new to this update), involving 3282 children: 16 RCTs (involving 3204 children) and one quasi-RCT (involving 78 children). Children in all studies were under six years of age. Fifteen studies took place in urban areas of North America, one in Australia and one in China. Most studies were in areas with low socioeconomic status. Girls and boys were equally represented in those studies reporting this information. The duration of the intervention ranged from three months to 24 months in 15 studies, while two studies performed interventions on a single occasion. Follow-up periods ranged from three months to eight years. Three RCTs were at low risk of bias in all assessed domains. The other 14 studies were at unclear or high risk of bias; for example, we considered two RCTs and one quasi-RCT at high risk of selection bias and six RCTs at high risk of attrition bias. National or international research grants or governments funded 15 studies, while the other two did not report their funding sources. Education interventions versus no intervention None of the included studies in this comparison assessed effects on cognitive or neurobehavioural outcomes, or adverse events. All studies reported data on blood lead level outcomes. Educational interventions showed there was probably no evidence of a difference in reducing blood lead levels (continuous: mean difference (MD) -0.03, 95% confidence interval (CI) -0.13 to 0.07; I² = 0%; 5 studies, 815 participants; moderate-certainty evidence; log-transformed data), or in reducing floor dust levels (MD -0.07, 95% CI -0.37 to 0.24; I² = 0%; 2 studies, 318 participants; moderate-certainty evidence). Environmental interventions versus no intervention Dust control: one study in this comparison reported data on cognitive and neurobehavioural outcomes, and on adverse events in children. The study showed numerically there may be better neurobehavioural outcomes in children of the intervention group. However, differences were small and the CI included both a beneficial and non-beneficial effect of the environmental intervention (e.g. mental development (Bayley Scales of Infant Development-II): MD 0.1, 95% CI -2.1 to 2.4; 1 study, 302 participants; low-certainty evidence). The same study did not observe any adverse events related to the intervention during the eight-year follow-up, but observed two children with adverse events in the control group (1 study, 355 participants; very low-certainty evidence). Meta-analysis also found no evidence of effectiveness on blood lead levels (continuous: MD -0.02, 95% CI -0.09 to 0.06; I² = 0%; 4 studies, 565 participants; moderate-certainty evidence; log-transformed data). We could not pool the data regarding floor dust levels, but studies reported that there may be no evidence of a difference between the groups (very low-certainty evidence). Soil abatement: the two studies assessing this environmental intervention only reported on the outcome of 'blood lead level'. One study showed a small effect on blood lead level reduction, while the other study showed no effect. Therefore, we deem the current evidence insufficient to draw conclusions about the effectiveness of soil abatement (very low-certainty evidence). Combination of educational and environmental interventions versus standard education Studies in this comparison only reported on blood lead levels and dust lead levels. We could not pool the studies in a meta-analysis due to substantial differences between the studies. Since the studies reported inconsistent results, the evidence is currently insufficient to clarify whether a combination of interventions reduces blood lead levels and floor dust levels (very low-certainty evidence).

AUTHORS' CONCLUSIONS

Based on available evidence, household educational interventions and environmental interventions (namely dust control measures) show no evidence of a difference in reducing blood lead levels in children as a population health measure. The evidence of the effects of environmental interventions on cognitive and neurobehavioural outcomes and adverse events is uncertain too. Further trials are required to establish the most effective intervention for reducing or even preventing further lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in low- and middle-income countries and in differing socioeconomic groups in high-income countries.

Lead seasonality in humans, animals, and the natural environment

Lead adversely impacts the health of humans, animals, and the natural environment. Higher lead burdens in warm weather occur in humans, domesticated and wild animals; land and water species; urban and rural, developed and pristine environments. The array of evidence suggests that lead seasonality is multifactorial within the natural world, including humans. Seasonally higher temperatures, solar radiation, humidity and anthropogenic pollution result in lower pH (acidification) in air, water and soil. Environmental acidification increases lead's bioavailability and mobility thus intensifying human, animal and plant exposures. In addition, lead seasonality in the biosphere is influenced by higher growth rates, slightly increased exposures, and more Vitamin D metabolism. Methodologically, we applied a One Health perspective to EPA's Integrated Science Assessments of Lead to review the published literature, supplemented with subsequent and related publications to assess data on the seasonality of lead exposure across species and through the earth's systems. Our integrated assessment suggests that: 1) 'Seasonality' is a multifactorial, terrestrial phenomenon affecting the natural world; human activities have exacerbated natural cyclicities that impact lead exposures across species. 2) To be sustainable, human lead remediation strategies must consider the total environment. 3) Global warming and climate change events may increase lead exposures and toxicity to all species throughout the natural environment.

Does soil track-in contribute to house dust concentrations of perfluoroalkyl acids (PFAAs) in areas affected by soil or water contamination?

The Minnesota Department of Health measured levels of perfluoroalkyl acids (PFAAs) in house dust at homes in communities impacted by PFAA-contaminated soil and drinking water to determine whether PFAAs in soil outside the home are associated with concentrations in dust. House dust samples from both interior living spaces and entryways to the yard were collected and analyzed separately based on the presumption that PFAAs in entryway dust may better reflect "track-in" of PFAAs into the home from contaminated soil or lawns irrigated with contaminated water. PFAA detections and concentrations in living rooms were significantly higher compared to entryways; and concentrations in both sampling locations were higher than corresponding soil concentrations, suggesting that interior sources were the main contributors to PFAAs in house dust. PFAA dust concentrations in entryways were significantly associated with living room dust levels for all analytes except PFBA. Relationships between entryway dust and soil were only seen for one PFAA (PFOA). However, median concentrations of PFOA in entryway and living room dust were 35 and 70 times higher (respectively) than in soil, which highlights the lack of importance of PFAA soil track-in as a contributor to dust concentration in this setting. Due to the small sample size, larger scale studies are needed to further assess the potential for migration of PFAA contaminated soil to indoor dust.

Household interventions for preventing domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children, and trials have tested many household interventions to prevent lead exposure. This is an update of the original review, first published in 2008.

OBJECTIVES

To assess the effects of household interventions for preventing or reducing lead exposure in children, as measured by improvements in cognitive and neurobehavioural development, reductions in blood lead levels and reductions in household dust lead levels.

SEARCH METHODS

In May 2016 we searched CENTRAL, Ovid MEDLINE, Embase, nine other databases and two trials registers: the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov. We also checked the reference lists of relevant studies and contacted experts to find unpublished studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of household educational or environmental interventions, or combinations of interventions to prevent lead exposure in children (from birth to 18 years of age), where investigators reported at least one standardised outcome measure.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included 14 studies involving 2643 children: 13 RCTs (involving 2565 children) and one quasi-RCT (involving 78 children). Children in all studies were under six years of age. Thirteen studies took place in urban areas of North America, and one was in Australia. Most studies were in areas with low socioeconomic status. Girls and boys were equally represented in all studies. The duration of the intervention ranged from 3 months to 24 months in 12 studies, while 2 studies performed interventions on a single occasion. Follow-up periods ranged from 6 months to 48 months. Three RCTs were at low risk of bias in all assessed domains. We rated two RCTs and one quasi-RCT as being at high risk of selection bias and six RCTs as being at high risk of attrition bias. For educational interventions, we rated the quality of evidence to be high for continuous blood lead levels and moderate for all other outcomes. For environmental interventions, we assessed the quality of evidence as moderate to low. National or international research grants or governments funded 12 studies, while the other 2 did not report their funding sources.No studies reported on cognitive or neurobehavioural outcomes. No studies reported on adverse events in children. All studies reported blood lead level outcomes.We put studies into subgroups according to their intervention type. We performed meta-analyses of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I² = 0%; 5 studies; N = 815; high quality evidence (log transformed); dichotomous ≥ 10.0 µg/dL (≥ 0.48 µmol/L): risk ratio (RR) 1.02, 95% CI 0.79 to 1.30; I² = 0%; 4 studies; N = 520; moderate quality evidence; dichotomous ≥ 15.0 µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09; I² = 0%; 4 studies; N = 520; moderate quality evidence). Meta-analysis for the dust control subgroup also found no evidence of effectiveness on blood lead levels (continuous: MD -0.15, 95% CI -0.42 to 0.11; I² = 90%; 3 studies; N = 298; low quality evidence (log transformed); dichotomous ≥ 10.0 µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18; I² = 0; 2 studies; N = 210; moderate quality evidence; dichotomous ≥ 15.0 µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07; I² = 56%; 2 studies; N = 210; low quality evidence). After adjusting the dust control subgroup for clustering in meta-analysis, we found no evidence of effectiveness. We could not pool the studies using soil abatement (removal and replacement) and combination intervention groups in a meta-analysis due to substantial differences between studies, and generalisability or reproducibility of the results from these studies is unknown. Therefore, there is currently insufficient evidence to clarify whether soil abatement or a combination of interventions reduces blood lead levels.

AUTHORS' CONCLUSIONS

Based on current knowledge, household educational interventions are ineffective in reducing blood lead levels in children as a population health measure. Dust control interventions may lead to little or no difference in blood lead levels (the quality of evidence was moderate to low, meaning that future research is likely to change these results). There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions. No study reported on cognitive or neurobehavioural outcomes or adverse events. These patient-relevant outcomes would have been of great interest to draw conclusions for practice.Further trials are required to establish the most effective intervention for preventing lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in low- and middle-income countries and in differing socioeconomic groups in high-income countries.

Recommendations from Lead Poisoning Prevention Program Participants: Best Practices

We present a program evaluation of the Phillips Lead Project, a 5-year study of the effectiveness of culture-specific, peer education in maintaining low blood lead levels of children in an inner-city neighborhood. We conducted focus groups to understand how project participants felt about the various strategies employed by the Lead Project. The purpose of this article is to describe their reactions to the project and make recommendations concerning appropriate educational strategies for lead poisoning prevention projects being undertaken in similar communities. Although this project was a research study, many of its methods, and participants’ reactions to those methods, are relevant to non-research prevention programs and may be generalizable to other health issues besides lead poisoning.

Environmental Health Promotion Interventions: Considerations for Preparation and Practice

Interventions to address current, future, and potential public health dilemmas, such as air pollution, urban sprawl, brown field reclamation, and threats of intentional toxic exposures would benefit from a synergy between the disciplines of environmental health and health education. A comparison between the Protocol for Assessing Community Excellence in Environmental Health and the PRECEDE-PROCEED model used in health education illustrates some similarities and differences in terminology, assessment procedures, intervention design, and types of evidence used by the two disciplines. Promising intervention strategies draw on the expertise of both fields and include social action, policy and media advocacy, coalition building, organizational change, lay health advisers, risk communication, and tailored educational messages. Appropriate targets of change can range from the equitable distribution of resources to individual behavior change. Significant interdisciplinary evaluation research is necessary to accelerate the identification of successful models for reducing the burden of environmental health problems in communities.

Detectable Blood Lead Level and Body Size in Early Childhood

Rates of childhood obesity have risen at the same time rates of high blood lead levels (BLLs) have fallen. Recent studies suggest that higher BLL is inversely associated with body size in older children (ages 3-19 years). No contemporaneous studies have examined if having a detectable BLL is associated with body size in very early childhood. We examined if detectable BLL is associated with body size in early childhood. A total of 299 birth cohort participants completed a study visit at ages 2-3 years with weight and height measurements; prior to this clinic visit, a BLL was drawn as part of routine clinical care. Body mass index (BMI) percentile and Z-score were calculated; children with BMI ≥85th percentile were considered overweight/obese at age of 2 years. Detectable BLL was defined as BLL ≥1 μg/dL. A total of 131 (43.8 %) children had a detectable BLL measured at mean aged 15.4 ± 5.5 months. Mean age at body size assessment was 2.2 ± 0.3 years (53.2 % male, 68.6 % African-American). After adjusting for race, sex, and birth weight, children with a detectable BLL had a 43 % lower risk of BMI ≥85th percentile (P = 0.041) and a 0.35-unit lower BMI Z-score (P = 0.008) compared to children without a detectable BLL. Neither race nor sex modified this association (all interactions P > 0.21). Consistent with recent studies in older children, having a detectable BLL was associated with smaller body size at ages 2-3 years. Additional research on the mechanism of this association is needed but may include mechanisms of appetite suppression via lead.

Household interventions for preventing domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008.

OBJECTIVES

To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development.

SEARCH METHODS

We identified trials through electronic searches of CENTRAL (2012, Issue 1), MEDLINE (1948 to January Week 1 2012), EMBASE (1980 to Week 2 2012), CINAHL (1937 to January 2012), PsycINFO (1887 to January Week 2 2012), ERIC (1966 to January 2012), Sociological Abstracts (1952 to January 2012), Science Citation Index (1970 to 20 January 2012), ZETOC (20 January 2012), LILACS (20 January 2012), Dissertation Abstracts (late 1960s to January 2012), ClinicalTrials.gov (19 January 2012), Current Controlled Trials (19 January 2012), Australian New Zealand Clinical Trials Registry (19 January 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information.

MAIN RESULTS

We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I(2) = 0 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): relative risk (RR) 1.02, 95% CI 0.79 to 1.30, I(2)=0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09, I(2) = 0). Meta-analysis for the dust control subgroup also found no evidence of effectiveness (continuous: MD -0.15, 95% CI -0.42 to 0.11, I(2) = 0.9 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18, I(2) =0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07, I(2) = 0.56). When meta-analysis for the dust control subgroup was adjusted for clustering, no statistical significant benefit was incurred. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies.

AUTHORS' CONCLUSIONS

Based on current knowledge, household educational or dust control interventions are ineffective in reducing blood lead levels in children as a population health measure. There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions.Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in developing countries and in differing socioeconomic groups in developed countries.

Using behavior change to reduce child lead exposure in resource-poor settings: a formative study

The objective of this formative research was to explore the acceptability and feasibility of changing housekeeping behaviors as a low-cost approach that may reduce childhood lead exposure in Johannesburg, South Africa. Using the Trials of Improved Practices (TIPs) methodology, modified housekeeping behaviors were negotiated with participants who chose the behaviors they wanted to try and then performed them in their homes over 4 weeks. Researchers interviewed them at the end of the month to understand their experience of trying out the behaviors. The modified behaviors offered to each participant were as follows: cleaning window sills with detergent and water, cleaning window sills more frequently, mopping floors with two buckets (one with soapy water for washing and one with clean water for rinsing), mopping floors more frequently, dusting surfaces with detergent and water and dusting surfaces more frequently. Participants found cleaning window sills with soap and water and cleaning them more often the most acceptable and feasible of behavior modifications. Environmental samples showed a significant reduction in lead dust on window sills. These findings can assist in the development of acceptable and feasible medium-term interventions to reduce childhood lead exposure in resource-poor settings until more robust health policies are implemented.

Persistent organic pollutants in dust from older homes: learning from lead

OBJECTIVES

We aimed to (1) evaluate the relation between home age and concentrations of multiple chemical contaminants in settled dust and (2) discuss the feasibility of using lead hazard controls to reduce children's exposure to persistent organic pollutants.

METHODS

As part of the California Childhood Leukemia Study, from 2001 to 2007, we used a high-volume small surface sampler and household vacuum cleaners to collect dust samples from 583 homes and analyzed the samples for 94 chemicals with gas chromatography-mass spectrometry and inductively coupled plasma mass spectrometry. We evaluated relations between chemical concentrations in dust and home age with Spearman rank correlation coefficients.

RESULTS

Dust concentrations of lead, polychlorinated biphenyls, organochlorine insecticides, and polycyclic aromatic hydrocarbons were correlated with home age (ρ > 0.2; P < .001), whereas concentrations of pyrethroid insecticides and polybrominated diphenyl ethers were not.

CONCLUSIONS

Dust in older homes contains higher levels of multiple, persistent chemicals than does dust in newer homes. Further development of strategies to reduce chemical exposures for children living in older homes is warranted.

Home safety education and provision of safety equipment for injury prevention (Review)

BACKGROUND

In industrialised countries injuries (including burns, poisoning or drowning) are the leading cause of childhood death and steep social gradients exist in child injury mortality and morbidity. The majority of injuries in pre-school children occur at home but there is little meta-analytic evidence that child home safety interventions reduce injury rates or improve a range of safety practices, and little evidence on their effect by social group.

OBJECTIVES

We evaluated the effectiveness of home safety education, with or without the provision of low cost, discounted or free equipment (hereafter referred to as home safety interventions), in reducing child injury rates or increasing home safety practices and whether the effect varied by social group.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2009, Issue 2) in The Cochrane Library, MEDLINE (Ovid), EMBASE (Ovid), PsycINFO (Ovid), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Social Sciences Citation Index (SSCI), ISI Web of Science: Conference Proceedings Citation Index- Science (CPCI-S), CINAHL (EBSCO) and DARE (2009, Issue 2) in The Cochrane Library. We also searched websites and conference proceedings and searched the bibliographies of relevant studies and previously published reviews. We contacted authors of included studies as well as relevant organisations. The most recent search for trials was May 2009.

SELECTION CRITERIA

Randomised controlled trials (RCTs), non-randomised controlled trials and controlled before and after (CBA) studies where home safety education with or without the provision of safety equipment was provided to those aged 19 years and under, and which reported injury, safety practices or possession of safety equipment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We attempted to obtain individual participant level data (IPD) for all included studies and summary data and IPD were simultaneously combined in meta-regressions by social and demographic variables. Pooled incidence rate ratios (IRR) were calculated for injuries which occurred during the studies, and pooled odds ratios were calculated for the uptake of safety equipment or safety practices, with 95% confidence intervals.

MAIN RESULTS

Ninety-eight studies, involving 2,605,044 people, are included in this review. Fifty-four studies involving 812,705 people were comparable enough to be included in at least one meta-analysis. Thirty-five (65%) studies were RCTs. Nineteen (35%) of the studies included in the meta-analysis provided IPD. There was a lack of evidence that home safety interventions reduced rates of thermal injuries or poisoning. There was some evidence that interventions may reduce injury rates after adjusting CBA studies for baseline injury rates (IRR 0.89, 95% CI 0.78 to 1.01). Greater reductions in injury rates were found for interventions delivered in the home (IRR 0.75, 95% CI 0.62 to 0.91), and for those interventions not providing safety equipment (IRR 0.78, 95% CI 0.66 to 0.92). Home safety interventions were effective in increasing the proportion of families with safe hot tap water temperatures (OR 1.41, 95% CI 1.07 to 1.86), functional smoke alarms (OR 1.81, 95% CI 1.30 to 2.52), a fire escape plan (OR 2.01, 95% CI 1.45 to 2.77), storing medicines (OR 1.53, 95% CI 1.27 to 1.84) and cleaning products (OR 1.55, 95% CI 1.22 to 1.96) out of reach, having syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) or poison control centre numbers accessible (OR 3.30, 95% CI 1.70 to 6.39), having fitted stair gates (OR 1.61, 95% CI 1.19 to 2.17), and having socket covers on unused sockets (OR 2.69, 95% CI 1.46 to 4.96). Interventions providing free, low cost or discounted safety equipment appeared to be more effective in improving some safety practices than those interventions not doing so. There was no consistent evidence that interventions were less effective in families whose children were at greater risk of injury.

AUTHORS' CONCLUSIONS

Home safety interventions most commonly provided as one-to-one, face-to-face education, especially with the provision of safety equipment, are effective in increasing a range of safety practices. There is some evidence that such interventions may reduce injury rates, particularly where interventions are provided at home. Conflicting findings regarding interventions providing safety equipment on safety practices and injury outcomes are likely to be explained by two large studies; one clinic-based study provided equipment but did not reduce injury rates and one school-based study did not provide equipment but did demonstrate a significant reduction in injury rates. There was no consistent evidence that home safety education, with or without the provision of safety equipment, was less effective in those participants at greater risk of injury. Further studies are still required to confirm these findings with respect to injury rates.

Determinants of polychlorinated biphenyls in dust from homes in California, USA

Polychlorinated biphenyl (PCB) production ceased in the U.S. over 30 years ago, but these persistent chemicals remain ubiquitous contaminants. Here, we evaluate potential determinants of PCB levels in dust from California homes including characteristics of the residence as well as the residents' habits and occupations. Dust was collected from 415 households as part of a large case-control study (the Northern California Childhood Leukaemia Study), using a high-volume small surface sampler. Dust concentrations of 6 PCBs (PCB-105, PCB-118, PCB-138, PCB-153, PCB-170, and PCB-180) were measured using gas chromatography-mass spectrometry. Individual PCB detection rates ranged from 9% to 54% with PCB concentrations ranging from below detection (1 or 2 ng g (-1)) to 270 ng g(-1) and PCB loadings ranging from below detection to 960 ng m (-2). Multivariable linear and logistic regression models were used to identify potential determinants of residential PCB contamination based on in-home interviews and residential geographic locations. We observed that residences built prior to 1980 had higher odds of PCB detection and higher PCB loadings than more recently constructed homes. Households where residents typically did not remove their shoes had higher PCB dust loadings than households where residents did. PCBs were less likely to be detected in carpet dust from households that had frequently vacuumed or replaced carpets compared to other households. Since we used a cross-sectional dust sampling protocol and report significant, but modest, effects of these determinants on levels of PCBs in residential dust, our results should be interpreted with caution. Longitudinal studies to determine optimal strategies for reducing PCBs in homes are warranted.

Two decades of exposure assessment studies on chromate production waste in Jersey City, New Jersey--what we have learned about exposure characterization and its value to public health and remediation

During much of the twentieth century, Jersey City, New Jersey was the leading center of chromate production in the United States. Chromate production produced huge volumes of chromium ore-processing residue containing many parts per million of hexavalent chromium. Starting in the 1990s, we undertook a series of studies to identify exposed populations, sources and pathways of exposure and the effectiveness of remediation activities in Jersey City. These studies revealed the effectiveness and success of the remediation activities. The sequence of studies presented here, builds on the lessons learned from each preceding study and illustrates how these studies advanced the field of exposure science in important ways, including the use of household dust as a measure of exposure to contaminants originating in the outdoor environment; development of effective and reproducible dust sampling; use of household dust to track temporal changes in exposure; understanding of the spatial relationship between sources of passive outdoor particulate emissions and residential exposure; use of focused biomonitoring to assess exposure under conditions of large inter-individual variability; and utility of linking environmental monitoring and biomonitoring. For chromium, the studies have demonstrated the use of Cr(+6)-specific analytical methods for measuring low concentrations of Cr(+6) in household dust and understanding of the occurrence of Cr(+6) in the background residential environment. We strongly recommend that environmental and public health agencies evaluate sites for their potential for off-site exposure and apply these tools in cases with significant potential as appropriate. This approach is especially important when contamination is widespread and/or a large population is potentially exposed. In such cases, these tools should be used to identify, characterize and then reduce the exposure to the off-site as well as on-site population. Importantly, these tools can be used in a demonstrable and quantifiable manner to provide both clarity and closure to concerned stakeholders.

Housing interventions and control of health-related chemical agents: a review of the evidence

Subject matter experts systematically reviewed evidence on the effectiveness of housing interventions that affect health outcomes associated with exposure to chemical agents, such as pesticides, lead, volatile organic compounds, as well as the radon gas. Particulates were also examined, and the role of ventilation on exposures was assessed. The review included both published literature and peer-reviewed reports from the US Environmental Protection Agency. Four of the 14 interventions reviewed had sufficient evidence to demonstrate their effectiveness and are ready for implementation: radon air mitigation by using active soil depressurization systems, integrated pest management to reduce exposures to pesticides, smoke-free home policies making indoor areas smoke-free (ie, no smoking allowed anywhere at any time), and residential lead hazard control. Four interventions needed more field evaluation, 3 needed formative research, and 3 either had no sufficient evidence of effectiveness or had evidence the interventions were ineffective. This evidence review shows that housing improvements are likely to help reduce radon-induced lung cancer, cardiovascular mortality related to secondhand smoke, and neurological effects from exposure to pesticides and lead paint. Investing in housing interventions may yield important savings from reduced disease and injury from avoidable exposures to chemical agents.

Relative contribution of potential modes of surface dust lead contamination in the homes of boatyard caulkers

OBJECTIVES

The aim of this study was to quantify the relative contributions to surface lead contamination of boat-caulkers' houses of three contamination modes, namely "take-home" lead from the caulker, "natural" spatial dispersal from boatyard to household and "redistribution" of accumulated lead-laden dust within the house.

METHODS

Boat-caulkers' houses situated in areas surrounding boat repair yards were recruited. Caulkers' houses that were located close together were divided into location-matched pairs, within which one was randomly assigned to be given a cleaning and designated a CL house, and the other was to be left uncleaned and designated a NCL house. Geographically isolated caulker's houses were randomly assigned to one of the two categories. The nearest non-boatyard worker's house (NB) was additionally recruited for each set. The surface lead loading rate (SLLR), defined as the mass of lead deposited in dust per unit area of surface per unit time, was measured over a period of 3 mo in all houses, and the data were modeled using linear mixed effects regression.

RESULTS

Adjusted values of SLLR differed only slightly between CL and NCL houses (0.96 to 1.02 times) but were between 1.65 and 2.03 times higher in CL and NCL houses than in NB houses depending on proximity to the boatyard and between 2.12 and 2.61 times higher in houses within one km of a boatyard than in more distant houses depending on category of house.

CONCLUSIONS

Newly deposited dust lead likely resulted from the take-home and spatial dispersion modes. The contribution of redistribution is very small.

Home safety education and provision of safety equipment for injury prevention

BACKGROUND

In industrialised countries injuries (including burns, poisoning or drowning) are the leading cause of childhood death and steep social gradients exist in child injury mortality and morbidity. The majority of injuries in pre-school children occur at home but there is little meta-analytic evidence that child home safety interventions reduce injury rates or improve a range of safety practices, and little evidence on their effect by social group.

OBJECTIVES

We evaluated the effectiveness of home safety education, with or without the provision of low cost, discounted or free equipment (hereafter referred to as home safety interventions), in reducing child injury rates or increasing home safety practices and whether the effect varied by social group.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2009, Issue 2) in The Cochrane Library, MEDLINE (Ovid), EMBASE (Ovid), PsycINFO (Ovid), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Social Sciences Citation Index (SSCI), ISI Web of Science: Conference Proceedings Citation Index- Science (CPCI-S), CINAHL (EBSCO) and DARE (2009, Issue 2) in The Cochrane Library. We also searched websites and conference proceedings and searched the bibliographies of relevant studies and previously published reviews. We contacted authors of included studies as well as relevant organisations. The most recent search for trials was May 2009.

SELECTION CRITERIA

Randomised controlled trials (RCTs), non-randomised controlled trials and controlled before and after (CBA) studies where home safety education with or without the provision of safety equipment was provided to those aged 19 years and under, and which reported injury, safety practices or possession of safety equipment.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We attempted to obtain individual participant level data (IPD) for all included studies and summary data and IPD were simultaneously combined in meta-regressions by social and demographic variables. Pooled incidence rate ratios (IRR) were calculated for injuries which occurred during the studies, and pooled odds ratios were calculated for the uptake of safety equipment or safety practices, with 95% confidence intervals.

MAIN RESULTS

Ninety-eight studies, involving 2,605,044 people, are included in this review. Fifty-four studies involving 812,705 people were comparable enough to be included in at least one meta-analysis. Thirty-five (65%) studies were RCTs. Nineteen (35%) of the studies included in the meta-analysis provided IPD.There was a lack of evidence that home safety interventions reduced rates of thermal injuries or poisoning. There was some evidence that interventions may reduce injury rates after adjusting CBA studies for baseline injury rates (IRR 0.89, 95% CI 0.78 to 1.01). Greater reductions in injury rates were found for interventions delivered in the home (IRR 0.75, 95% CI 0.62 to 0.91), and for those interventions not providing safety equipment (IRR 0.78, 95% CI 0.66 to 0.92).Home safety interventions were effective in increasing the proportion of families with safe hot tap water temperatures (OR 1.41, 95% CI 1.07 to 1.86), functional smoke alarms (OR 1.81, 95% CI 1.30 to 2.52), a fire escape plan (OR 2.01, 95% CI 1.45 to 2.77), storing medicines (OR 1.53, 95% CI 1.27 to 1.84) and cleaning products (OR 1.55, 95% CI 1.22 to 1.96) out of reach, having syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) or poison control centre numbers accessible (OR 3.30, 95% CI 1.70 to 6.39), having fitted stair gates (OR 1.61, 95% CI 1.19 to 2.17), and having socket covers on unused sockets (OR 2.69, 95% CI 1.46 to 4.96).Interventions providing free, low cost or discounted safety equipment appeared to be more effective in improving some safety practices than those interventions not doing so. There was no consistent evidence that interventions were less effective in families whose children were at greater risk of injury.

AUTHORS' CONCLUSIONS

Home safety interventions most commonly provided as one-to-one, face-to-face education, especially with the provision of safety equipment, are effective in increasing a range of safety practices. There is some evidence that such interventions may reduce injury rates, particularly where interventions are provided at home. Conflicting findings regarding interventions providing safety equipment on safety practices and injury outcomes are likely to be explained by two large studies; one clinic-based study provided equipment but did not reduce injury rates and one school-based study did not provide equipment but did demonstrate a significant reduction in injury rates. There was no consistent evidence that home safety education, with or without the provision of safety equipment, was less effective in those participants at greater risk of injury. Further studies are still required to confirm these findings with respect to injury rates.

Serum PBDEs in a North Carolina toddler cohort: associations with handwipes, house dust, and socioeconomic variables

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are persistent, bioaccumulative, and endocrine-disrupting chemicals.

OBJECTIVES

We used handwipes to estimate exposure to PBDEs in house dust among toddlers and examined sex, age, breast-feeding, race, and parents' education as predictors of serum PBDEs.

METHODS

Eighty-three children from 12 to 36 months of age were enrolled in North Carolina between May 2009 and November 2010. Blood, handwipe, and house dust samples were collected and analyzed for PBDEs. A questionnaire was administered to collect demographic data.

RESULTS

PBDEs were detected in all serum samples (geometric mean for ΣpentaBDE in serum was 43.3 ng/g lipid), 98% of the handwipe samples, and 100% of the dust samples. Serum ΣpentaBDEs were significantly correlated with both handwipe and house dust ΣpentaBDE levels, but were more strongly associated with handwipe levels (r = 0.57; p < 0.001 vs. r = 0.35; p < 0.01). Multivariate model estimates revealed that handwipe levels, child's sex, child's age, and father's education accounted for 39% of the variation in serum ΣBDE3 levels (sum of BDEs 47, 99, and 100). In contrast, age, handwipe levels, and breast-feeding duration explained 39% of the variation in serum BDE 153.

CONCLUSIONS

Our study suggests that hand-to-mouth activity may be a significant source of exposure to PBDEs. Furthermore, age, socioeconomic status, and breast-feeding were significant predictors of exposure, but associations varied by congener. Specifically, serum ΣBDE3 was inversely associated with socioeconomic status, whereas serum BDE-153 was positively associated with duration of breast-feeding and mother's education.

Household interventions for preventing domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008.

OBJECTIVES

To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development.

SEARCH METHODS

We identified trials through electronic searches of CENTRAL (The Cochrane Library, 2010, Issue 2), MEDLINE (1948 to April Week 1 2012), EMBASE (1980 to 2012 Week 2), CINAHL (1937 to 20 Jan 2012), PsycINFO (1887 to Dec week 2 2011), ERIC (1966 to 17 Jan 2012), Sociological Abstracts (1952 to 20 January 2012), Science Citation Index (1970 to 20 Jan 2012), ZETOC (20 Jan 2012), LILACS (20 Jan 2012), Dissertation Abstracts (late 1960s to Jan 2012), ClinicalTrials.gov (20 Jan 2012), Current Controlled Trials (Jan 2012), Australian New Zealand Clinical Trials Registry (Jan 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information.

MAIN RESULTS

We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I(2) = 0 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): relative risk (RR) 1.02, 95% CI 0.79 to 1.30, I(2)=0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09, I(2) = 0). Meta-analysis for the dust control subgroup also found no evidence of effectiveness (continuous: MD -0.15, 95% CI -0.42 to 0.11, I(2) = 0.9 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18, I(2) =0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07, I(2) = 0.56). When meta-analysis for the dust control subgroup was adjusted for clustering, no statistical significant benefit was incurred. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies.

AUTHORS' CONCLUSIONS

Based on current knowledge, household educational or dust control interventions are ineffective in reducing blood lead levels in children as a population health measure. There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions.Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in developing countries and in differing socioeconomic groups in developed countries.

Association of dental enamel lead levels with risk factors for environmental exposure

OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 14-18 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Skin lead contamination of family members of boat-caulkers in southern Thailand

Powdered lead oxide (Pb(3)O(4)) is used in the wooden-boat repair industry as a constituent of the caulking material. This study compared skin lead of household members of caulkers' and control homes, and examined the relationship of household member's skin lead with household floor lead loading (FLL) and dust lead content (DLC). FLL and DLC were measured in 67 caulkers' houses and 46 nearby houses with no known lead exposure. In each household, wipe specimens of skin lead were obtained from one selected family member. Hand lead loading (HdLL) and foot lead loading (FtLL) were significantly higher in family members of caulkers than controls (geometric mean 64.4 vs. 36.2 μg m(-2); p = 0.002 and 77.8 vs 43.8 μg m(-2); p = 0.002, respectively). This pattern mirrored FLL and DLC, which were also higher in caulkers' than in control houses (geometric mean 109.9 vs. 40.1 μg m(-2); p<0.001 and 434.8 vs 80.8 μg g(-1); p<0.001, respectively). Multiple linear regression modelling revealed FLL to be a better predictor than DLC for HdLL in all age groups and for FtLL in adult family members. In conclusion, skin lead levels are elevated in family members living in a lead-exposed worker's house and are related to the levels of household lead contamination.

Exposure science: a view of the past and milestones for the future

BACKGROUND

The study of human exposure to environmental toxicants has evolved as a scientific field over the past 30 years.

OBJECTIVES

This review provides a historical perspective on the growth of exposure science as a field, with some emphasis on the results from initial observational studies in obtaining information needed for generating hypotheses on significant human contact with environmental agents, testing the performance of models, and reducing exposures to protect public health.

DISCUSSION

Advances in activity pattern and behavioral research that established a suite of variables needed to accurately define contact and factors that influence contact are also discussed. The identification and characterization of these factors have played a pivotal role in the growth of the field and in developing exposure reduction strategies. Answers to two key questions on the relevance and fundamental value of exposure science to the fields of environmental health and risk management are presented as a path forward: a) What does one do with such exposure information? b) What roles does exposure science play in situations beyond observational analyses and interpretation?

CONCLUSIONS

The discussion identifies the need for more focused use of observational studies of exposure for epidemiologic analyses. Further, the introduction and use of new tools and approaches for hypothesis testing that can improve the use of exposure science in prevention research for risk management is needed to affect the source-to-effect continuum. A major restructuring of the field is not required to achieve innovation. However, additional resources for training and education are required to ensure that the potential for exposure science to play a central role in reducing and preventing excess risk within environmental/occupational health is achieved.

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.

Risk remaining from fine particle contaminants after vacuum cleaning of hard floor surfaces

In the indoor environment, settled surface dust often functions as a reservoir of hazardous particulate contaminants. In many circumstances, a major contributing source to the dust pool is exterior soil. Young children are particularly susceptible to exposure to both outdoor derived soil and indoor derived dust present in the indoor dust pool. This is because early in life the exploratory activities of the infant are dominated by touching and mouthing behavior. Inadvertent exposure to dust through mouth contact and hand-to-mouth activity is an inevitable consequence of infant development. Clean-up of indoor dust is, in many circumstances, critically important in efforts to minimize pediatric exposure. In this study, we examine the efficiency of vacuum cleaner removal of footwear-deposited soil on vinyl floor tiles. The study utilized a 5 x 10 foot (c. 152.5 x 305 cm) test surface composed of 1-foot-square (c. 30.5 x 30.5 cm) vinyl floor tiles. A composite test soil with moderately elevated levels of certain elements (e.g., Pb) was repeatedly introduced onto the floor surface by footwear track-on. The deposited soil was subsequently periodically removed from randomly selected tiles using a domestic vacuum cleaner. The mass and loading of soil elements on the tiles following vacuuming were determined both by wet wipe collection and by subsequent chemical analysis. It was found that vacuum cleaner removal eliminated much of the soil mass from the floor tiles. However, a small percentage of the mass was not removed and a portion of this residual mass could be picked up by moistened hand-lifts. Furthermore, although the post-vacuuming tile soil mass was sizably reduced, for some elements (notably Pb) the concentration in the residual soil was increased. We interpret this increased metal concentration to be a particle size effect with smaller particles (with a proportionately higher metal content) remaining in situ after vacuuming.

Measurement of polybrominated diphenyl ethers on hand wipes: estimating exposure from hand-to-mouth contact

Estimates of exposure to the flame-retardant polybrominated diphenyl ethers (PBDEs) in dust are very poor due to limited knowledge about dust ingestion. This study was undertaken to determine if PBDEs could be measured on hand wipes, and if so, to determine the distribution of levels present on the skin surface area to provide preliminary exposure estimates from hand-to-mouth contact. Hand wipes were collected from 33 individuals residing in the United States using sterile gauze pads soaked in isopropyl alcohol. The total PBDE residue collected on the wipes ranged from 2.60 to 1982 ng, with a median value of 130 ng, or normalized to hand surface area, a concentration of 135 pg/cm2. The fully brominated congener, BDE 209, was also detected and ranged from < DL to 270 ng with a median value of 26 ng. Congener patterns observed on the wipes were similar to patterns observed in house dust samples, consisting of congeners associated with the PentaBDE and DecaBDE mixtures, suggesting that the source of PBDEs to the hands may be dust particles. However, PBDE hand residues may also be a result of direct contact with PBDE-laden products, leading to adsorption to the skin surface oils. Repeated wipe sampling from three individuals suggests that sigmaPBDE levels on the hand may be relatively consistent for some individuals but not for others. Furthermore, levels of sigmaPBDEs were greater on the bottom of the hands relative to the top of the hands. Using these values we have calculated potential human exposure from hand-to-mouth contact. The median exposure estimates for children and adults are 1380 and 154 ng/day, respectively, whereas the 95th percentile exposure estimates were 6090 and 677 ng/day, respectively. These estimates are greater than dietary intake rates and suggest hand-to-mouth contact may be a key exposure route for PBDEs.

Household interventions for prevention of domestic lead exposure in children

BACKGROUND

Lead poisoning is associated with physical, cognitive and neurobehavioral impairment in children and many household interventions to prevent lead exposure have been trialled.

OBJECTIVES

To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development.

SEARCH STRATEGY

Trials were identified through electronic searches of CENTRAL 2006 (Issue 1), MEDLINE 1966 to March 2006, and thirteen other electronic databases and contacting experts to find unpublished studies.

SELECTION CRITERIA

Randomised and quasi randomised trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed all eligible studies for inclusion, assessed study quality and extracted data. Triallists were contacted to obtain missing information.

MAIN RESULTS

Twelve studies (2239 children) were included. All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. Studies were subgrouped according to their intervention type. Meta-analysis of both continuous and dichotomous data was performed for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: WMD 0.13, 95% CI -0.30, 0.56, I2 = 41.6; dichotomous >/= 10 microg/dL (>/= 0.48 micromol/l): RR 1.02 (95% CI 0.79, 1.30, I2 = 0); dichotomous >/= 15 microg/dL (>/=0.72 micromol/l): RR 0.60, 95% CI 0.33, 1.09, I2 = 0). Meta-analysis of the dichotomous data for the dust control subgroup found no evidence of effectiveness. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies.

AUTHORS' CONCLUSIONS

Currently there is no evidence of effectiveness for household interventions for education or dust control measures in reducing blood lead levels in children as a population health measure. There is insufficient evidence for soil abatement or combination interventions. Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements should include longer term follow up and measures of compliance as well as performing trials in developing countries and differing socio-economic groups in developed countries.

Cleaning efficacy of high-efficiency particulate air-filtered vacuuming and "dry steam" cleaning on carpet

Previous studies for lead exposure reduction have indicated the difficulty in reducing surface contamination of carpets with the use of regular vacuum cleaners. To find a solution, a household vacuum cleaner equipped with a high-efficiency particulate air (HEPA) filter and a dust finder indicator, and a "dry steam" cleaner previously reported effective in reducing dust mite allergens in carpets and mattresses were tested for effectiveness in reducing lead dust in carpets. Fifty homes of lead-exposed children were tested in New Jersey. A selected carpet in the living area of each home was tested with two interventions: half was cleaned by HEPA vacuuming twice (VAC-VAC) and the other half by dry steaming between the two HEPA vacuumings (VAC-DSC-VAC). Wipe and vacuum samples, representing surface dust and total dust collections, respectively, were taken before and after cleaning. The wipe and vacuum sample data indicated that both cleaning methods substantially reduced dust lead levels (p < 0.001). The mean percent reductions in lead loading were approximately 29% and 40% for the VAC-VAC and VAC-DSC-VAC interventions, respectively. The difference between the two postcleaning levels was statistically significant by wipe sampling (p = 0.038) but was marginally insignificant by vacuum sampling (p = 0.072). A subset of sample data collected before repeat vacuuming (VAC-DSC) suggested that repeat vacuuming after dry steam cleaning is unnecessary. In summary, slow and steady HEPA vacuuming with the help of a dust finder indicator reduces surface and overall lead dust in carpets, and dry steam cleaning further reduces surface lead contamination as compared with HEPA vacuuming alone.

Interpreting and managing blood lead levels of less than 10 microg/dL in children and reducing childhood exposure to lead: recommendations of the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention

Lead is a common environmental contaminant. Lead exposure is a preventable risk that exists in all areas of the United States. In children, lead is associated with impaired cognitive, motor, behavioral, and physical abilities. In 1991, the Centers for Disease Control and Prevention defined the blood lead level that should prompt public health actions as 10 microg/dL. Concurrently, the Centers for Disease Control and Prevention also recognized that a blood lead level of 10 microg/dL did not define a threshold for the harmful effects of lead. Research conducted since 1991 has strengthened the evidence that children's physical and mental development can be affected at blood lead levels of < 10 microg/dL. In this report we provide information to help clinicians understand blood lead levels < 10 microg/dL, identify gaps in knowledge concerning lead levels in this range, and outline strategies to reduce childhood exposures to lead. We also summarize scientific data relevant to counseling, blood lead screening, and lead-exposure risk assessment. To aid in the interpretation of blood lead levels, clinicians should understand the laboratory error range for blood lead values and, if possible, select a laboratory that achieves routine performance within +/-2 microg/dL. Clinicians should obtain an environmental history on all children they examine, provide families with lead-prevention counseling, and follow blood lead screening recommendations established for their areas. As circumstances permit, clinicians should consider referral to developmental programs for children at high risk for exposure to lead and more frequent rescreening of children with blood lead levels approaching 10 microg/dL. In addition, clinicians should direct parents to agencies and sources of information that will help them establish a lead-safe environment for their children. For these preventive strategies to succeed, partnerships between health care providers, families, and local public health and housing programs should be strengthened.

Home safety education and provision of safety equipment for injury prevention

BACKGROUND

In industrialised countries injuries are the leading cause of childhood death and steep social gradients exist in child injury mortality and morbidity. The majority of injuries in pre-school children occur at home, but there is little meta-analytic evidence that child home safety interventions improve a range of safety practices or reduce injury rates and little evidence on their effect by social group.

OBJECTIVES

We evaluated the effectiveness of home safety education, with or without the provision of low cost, discounted or free equipment in increasing home safety practices or reducing child injury rates and whether the effect varied by social group.

SEARCH STRATEGY

We searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, DARE, ASSIA, Psychinfo and Web of Science, plus a range of relevant web sites, conference proceedings and bibliographies. We contacted authors of included studies and surveyed a range of organisations.

SELECTION CRITERIA

Randomised controlled trials (RCTs), non-randomised controlled trials and controlled before and after studies where home safety education with or without the provision of safety equipment was provided to those aged 19 years and under, which reported safety practices, possession of safety equipment or injury.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We attempted to obtain individual participant level data (IPD) for all included studies and summary data and IPD were simultaneoulsy combined in meta-regressions by social and demographic variables.

MAIN RESULTS

Eighty studies were included; 37 of which were included in at least one meta-analysis. Twenty-three (62%) were RCTs and 12 (32%) included in the meta-analysis provided IPD. Home safety education was effective in increasing the proportion of families with safe hot tap water temperatures (OR 1.35, 95% CI 1.01 to 180), functional smoke alarms (OR 1.85, 95% CI 1.24 to 2.75), storing medicines (OR 1.58, 95% CI 1.18 to 2.13) and cleaning products (OR 1.63, 95% CI 1.22 to 2.17) out of reach, syrup of ipecac (OR 3.34, 95% CI 1.50 to 7.44) and poison control centre numbers accessible (OR 3.66, 95% CI 1.84 to 7.27), fitted stair gates (1.26, 95% CI 1.05 to 1.51), socket covers on unused sockets (OR 3.73, 95% CI 1.48 to 9.39) and storing sharp objects out of reach (OR 1.52, 95% CI 1.01 to 2.29). There was a lack of evidence that interventions reduced rates of thermal injuries, poisoning or a range of injuries. There was no consistent evidence that interventions were less effective in families whose children were at greater risk of injury.

AUTHORS' CONCLUSIONS

Home safety education provided most commonly as one-to-one, face-to-face education, in a clinical setting or at home, especially with the provision of safety equipment is effective in increasing a range of safety practices. There is a lack of evidence regarding its impact on child injury rates. There was no consistent evidence that home safety education, with or without the provision of safety equipment was less effective in those at greater risk of injury.

Blood lead levels in children and environmental lead contamination in Miami inner city, Florida

Studies have shown that the environmental conditions of the home are important predictors of health, especially in low-income communities. Understanding the relationship between the environment and health is crucial in the management of certain diseases. One health outcome related to the home environment among urban, minority, and low-income children is childhood lead poisoning. The most common sources of lead exposure for children are lead paint in older, dilapidated housing and contaminated dust and soil produced by accumulated residue of leaded gasoline. Blood lead levels (BLL) as low as 10 microg/dL in children are associated with impaired cognitive function, behavior difficulties, and reduced intelligence. Recently, it is suggested that the standard for intervention be lowered to BLL of 5 microg/dl. The objectives of our report were to assess the prevalence of lead poisoning among children under six years of age and to quantify and test the correlations between BLL in children and lead exposure levels in their environment. This cross-sectional analysis was restricted to 75 children under six years of age who lived in 6 zip code areas of inner city Miami. These locations exhibited unacceptably high levels of lead dust and soil in areas where children live and play. Using the 5 microg/dL as the cutoff point, the prevalence of lead poisoning among the study sample was 13.33%. The study revealed that lead levels in floor dust and window sill samples were positively and significantly correlated with BLL among children (p < 0.05). However, the correlations between BLL and the soil, air, and water samples were not significant. Based on this pilot study, a more comprehensive environmental study in surrounding inner city areas is warranted. Parental education on proper housecleaning techniques may also benefit those living in the high lead-exposed communities of inner city Miami.

Screening for elevated lead levels in childhood and pregnancy: an updated summary of evidence for the US Preventive Services Task Force

BACKGROUND

In 1996, the US Preventive Services Task Force provided recommendations for routine screening of asymptomatic children and pregnant women for elevated blood lead levels. This review updates the evidence for the benefits and harms of screening and intervention for elevated blood lead in asymptomatic children and pregnant women.

METHODS

We searched Medline, reference lists of review articles, and tables of contents of leading pediatric journals for studies published in 1995 or later that contained new information about the prevalence, diagnosis, natural course, or treatment of elevated lead levels in asymptomatic children aged 1 to 5 years and pregnant women.

RESULTS

The prevalence of elevated blood lead levels among children and women in the United States, like that in the general population, continues to decline sharply, primarily because of marked reductions in environmental exposure, but still varies substantially among different communities and populations. Similar to the findings in 1996, our searches did not identify direct evidence from controlled studies that screening children for elevated blood lead levels results in improved health outcomes, and there was no direct evidence identified from controlled studies that screening improves pregnancy or perinatal outcomes. No new relevant information regarding the accuracy of screening for lead toxicity was identified during the update, and we did not identify evidence that demonstrates that universal screening for blood lead results in better clinical outcomes than targeted screening. Substantial new relevant information regarding the adverse effects of screening and interventions was not identified.

CONCLUSIONS

There is no persuasive evidence that screening for elevated lead levels in asymptomatic children will improve clinical outcomes. For those children who are screened and found to have elevated levels, there is conflicting evidence demonstrating the clinical effectiveness of early detection and intervention.

Trials and tribulations of protecting children from environmental hazards

Society is increasingly aware of the profound impact that the environment has on children's health. Not surprisingly, there is increasing public scrutiny about children's exposures to environmental hazards, especially for disadvantaged children. These trends underscore the ethical imperative to develop a framework to protect children from environmental hazards. Such a framework must include regulations to test new chemicals and other potential hazards before they are marketed, a strategy to conduct research necessary to protect children from persistent hazards that are widely dispersed in their environment, stronger regulatory mechanisms to eliminate human exposures to recognized or suspected toxicants, and guidelines about the ethical conduct of research and the role of experimental trials that test the efficacy and safety of interventions to prevent or ameliorate children's exposure to persistent toxicants or hazards that are widely dispersed in their environment.

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.

An examination of knowledge, attitudes and practices related to lead exposure in South Western Nigeria

BACKGROUND

Lead is a highly toxic and pervasive metal. Chronic exposure to low levels is responsible for significant health effects, particularly in children. Prevention remains the best option for reducing childhood lead exposure, however the knowledge, attitudes and practices to lead exposure in many developing countries is not known.

METHODS

We conducted four focus group discussions (FGD) to evaluate knowledge attitudes and practices to lead exposure in Nigeria. An FGD guide was developed from the literature and preliminary discussion with members of the public. Participants in the FGD were randomly selected from adults living in Ibadan, South Western Nigeria in 2004.

RESULTS

We found that there was limited awareness of the sources of lead exposure in the domestic environment and participants had little knowledge of the health effects of chronic low-dose lead exposure.

CONCLUSION

We conclude that the findings of this study should be used, in conjunction with others, to develop appropriate health education intervention for lead exposure in the domestic environment.

The bioaccessibility of lead (Pb) from vacuumed house dust on carpets in urban residences

Risk assessments for toxicants in environmental media via oral exposure often rely on measurements of total concentration in a collected sample. However, the human digestive system cannot dissolute all of a toxicant present in the binding matrix, and cannot absorb it with nearly 100% efficiency. In vitro bioaccessibility has been developed as a method to estimate oral bioavailability of a toxicant using a physiologically-based extraction procedure. Bioaccessibility measurements are more physiologically relevant than strong acid leaching measurements of concentration. A method for measuring bioaccessible lead in house dust was derived from the bioaccessibility method currently used for heavy metals in contaminated soils. House dust was collected from carpets in typical urban residences. Bioaccessible lead was measured in house dust (<75 microm) from the homes of 15 participants. The bioaccessibility ranged from 52.4% to 77.2% in gastric fluid, and 4.9% to 32.1% in intestinal fluid. House dust samples from five homes were analyzed to assess the relationship among lead bioaccessibility of three particle size fractions (<75, 75-150, and 150-250 microm). Changes in lead bioaccessibility as a function of particle size fraction were not significant for gastric fluid (p= 0.7019); however they were significant for intestinal fluid (p= 0.0067). This decrease of bioaccessibility may result from the readsorption of dissolved lead onto the dust particles or precipitation of lead with phosphates in a high-pH environment. The bioaccessibility data obtained for two biofluids were applied to the IEUBK model, and results for intestinal bioaccessibility of lead provide support for the model default value of 30% lead bioavailability of dust as a reasonable population indicator for dose, but the higher values for gastric bioaccessibility of lead appeared to provide an upper bound that approached actual blood lead levels in the children living in the studied homes. This upper bound seemed to overcome some of the limitations of the model when it lacks child-specific activity data and characterization of all exposure routes.

Removal of lead contaminated dusts from hard surfaces

Government guidelines have widely recommended trisodium phosphate (TSP) or "lead-specific" cleaning detergents for removal of lead-contaminated dust (LCD) from hard surfaces, such as floors and window areas. The purpose of this study was to determine if low-phosphate, non-lead-specific cleaners could be used to efficiently remove LCD from 3 types of surfaces (vinyl flooring, wood, and wallpaper). Laboratory methods were developed and validated for simulating the doping, embedding, and sponge cleaning of the 3 surface types with 4 categories of cleaners: lead-specific detergents, nonionic cleaners, anionic cleaners, and trisodium phosphate (TSP). Vinyl flooring and wood were worn using artificial means. Materials were ashed, followed by ultrasound extraction, and anodic stripping voltammetry (ASV). One-way analysis of variance approach was used to evaluate the surface and detergent effects. Surface type was found to be a significant factor in removal of lead (p < 0.001). Vinyl flooring cleaned better than wallpaper by over 14% and wood cleaned better than wallpaper by 13%. There was no difference between the cleaning action of vinyl flooring and wood. No evidence was found to support the use of TSP or lead-specific detergents over all-purpose cleaning detergents for removal of lead-contaminated dusts. No-phosphate, non-lead-specific detergents are effective in sponge cleaning of lead-contaminated hard surfaces and childhood lead prevention programs should consider recommending all-purpose household detergents for removal of lead-contaminated dust after appropriate vacuuming.

A randomized, community-based trial of home visiting to reduce blood lead levels in children

OBJECTIVE

The objective of this study was to measure the effectiveness of intensive case management to reduce blood lead levels (BLLs) in children. Lead poisoning remains a common, preventable pediatric condition despite advances in reducing children's BLLs in the United States. Substantial evidence implicates lead paint-contaminated house dust as the most common high-dose source of lead in children's environments. Housekeeping and parental supervision also may contribute to risk for lead exposure.

METHODS

We conducted a community-based, randomized trial of comprehensive education and home visiting for families of children with BLLs 15 to 19 microg/dL. BLLs after 1 year of follow-up were compared for intervention group children, whose families received individualized education that was designed to address specific risks factors in a child's environment, and comparison group children, whose families received customary care, usually 1 or 2 educational visits. Environmental samples were collected at baseline and after 1 year of follow-up for intervention group children and compared with those of comparison group children, collected only at the end of study.

RESULTS

During the follow-up period, parents of intervention group children (n = 92) successfully decreased dust lead levels and significantly improved parent-child interaction and family housekeeping practices compared with comparison group children (n = 83). Overall geometric mean BLLs declined by 47%, and the difference in BLL by group was not significant (9 vs 8.3 microg/dL for intervention versus comparison group children, respectively.) After 1 year, nearly half of enrolled children had BLLs > or = 10 microg/dL.

CONCLUSIONS

Until a reservoir of lead-safe housing is created, programs that educate families to reduce environmental exposure are needed. Although providing families with quantitative information regarding lead contamination may have a role in short-term efforts to prevent lead exposure, these null findings suggest that it has little benefit once BLLs are elevated.

Needs Assessment and Intervention Strategies to Reduce Lead-Poisoning Risk Among Low-Income Ohio Toddlers

OBJECTIVE

Examine parental receipt of lead-poisoning prevention information and preferred methods of receiving this information.

DESIGN

Cross-sectional mailed survey of parents with children 1-2-year-old-enrolled in Medicaid.

SAMPLE

Respondents (n=532) were primarily female, white, with at least a high school education, and between the ages of 20-30 years.

MEASUREMENTS

Items from the Blood Lead Education and Screening Tool concerning parental receipt of lead-poisoning prevention information, persons with whom parents had discussed lead-poisoning prevention, parental receipt of a reminder about blood lead testing, and parents' preferred methods of obtaining lead-poisoning prevention information.

RESULTS

Most respondents had obtained lead-poisoning prevention information, but only 28% reported receiving a reminder to have their child's blood lead level assessed. Brochures and discussions with health care providers were the preferred methods of obtaining lead-poisoning prevention information. More minority respondents preferred receiving information via videos, billboards, and home visits. Younger parents preferred brochures, billboards, and speaking with someone at the health department or women, infants, and children supplemental nutrition (WIC). Most respondents identified multiple means by which they would like to receive lead-poisoning prevention information.

CONCLUSIONS

Implementation of individual, community, and system-level interventions by public health nurses are needed for comprehensive lead-poisoning prevention education.

Determination of polybrominated diphenyl ethers in indoor dust standard reference materials

Polybrominated diphenyl ethers (PBDEs) have been measured for the first time in three different indoor dust Standard Reference Materials (SRMs) prepared by the National Institute of Standards and Technology (NIST). Two of these, SRM 2583 (Trace Elements in Indoor Dust) and SRM 2584 (Trace Elements in Indoor Dust), have been certified previously for lead and other inorganic constituents. A third, SRM 2585 (Organics in Indoor Dust), is a new indoor dust reference material prepared by NIST which will be certified for various organic compounds (polycyclic aromatic hydrocarbons, pesticides and polychlorinated biphenyls) in 2005 including certified concentrations for 16 individual PBDE congeners and reference values for an additional three PBDE congeners. Dust SRMs were analyzed for 30 PBDE congeners using high-resolution gas chromatography combined with low-resolution mass spectrometry operated in both negative chemical ionization (GC/ECNI-MS) and electron impact ionization (GC/EI-MS) modes. Sensitivity was an order of magnitude higher using GC/ECNI-MS relative to GC/EI-MS. These SRMs have been characterized and compared to the three PBDE commercial products (pentaBDE, octaBDE and decaBDE). PentaBDE and DecaBDE were present in all three SRMs and were the dominant commercial products, making up approximately 33% and 58%, respectively. Recent studies suggest that house dust may be a leading source of human exposure to PBDEs. These SRMs are the first reference materials with certified concentrations for PBDEs, which will aid in validating future measurements of PBDEs in house dust and other similar matrices.

Determinants of temporal variability in NHEXAS-Maryland environmental concentrations, exposures, and biomarkers

The longitudinal NHEXAS-Maryland study measured metals, PAHs, and pesticides in several media to capture temporal variability. Questionnaires were concurrently administered to identify factors that influenced changes in contaminant levels over time. We constructed mixed-effects regression models for lead, phenanthrene, and chlorpyrifos (including metabolites) in indoor air, dust, dermal wipes, and biological fluids. Significant predictors represented time-varying activities as well as unchanging housing and demographic factors. There was little overlap among the models, with predictors generally reflecting the diverse characteristics of the target compounds. We estimated between- and within-person variance components to evaluate the reliability of the measurements. While only one measurement of lead in blood or chlopyrifos in dust was needed for a dependable estimate of an individual's average level, three to eight measurements were needed for most other compound/exposure medium combinations because of considerable temporal variability. Measurements in biological fluids and dust were generally more consistent than those in indoor air. The significant covariates in the full models preferentially reduced the between-person variance component. Since the regression models explained only 1-37% of the within-person variance, the questionnaires in this study provided only modest insight into the factors responsible for the temporal variability in the contaminant levels.

Is house dust the missing exposure pathway for PBDEs? An analysis of the urban fate and human exposure to PBDEs

Polybrominated diphenyl ether (PBDE) body burdens in North America are 20 times that of Europeans and some "high accumulation" individuals have burdens up to 1-2 orders of magnitude higher than median values, the reasons for which are not known. We estimated emissions and fate of sigma PBDEs (minus BDE-209) in a 470 km2 area of Toronto, Canada, using the Multi-media Urban Model (MUM-Fate). Using a combination of measured and modeled concentrations for indoor and outdoor air, soil, and dust plus measured concentrations in food, we estimated exposure to sigma PBDEs via soil, dust, and dietary ingestion and indoor and outdoor inhalation pathways. Fate calculations indicate that 57-85% of PBDE emissions to the outdoor environment originate from within Toronto and that the dominant removal process is advection by air to downwind locations. Inadvertent ingestion of house dust is the largest contributor to exposure of toddlers through to adults and is thus the main exposure pathway for all life stages other than the infant, including the nursing mother, who transfers PBDEs to her infant via human milk. The next major exposure pathway is dietary ingestion of animal and dairy products. Infant consumption of human milk is the largest contributor to lifetime exposure. Inadvertent ingestion of dust is the main exposure pathway for a scenario of occupational exposure in a computer recycling facility and a fish eater. Ingestion of dust can lead to almost 100-fold higher exposure than "average" for a toddler with a high dust intake rate living in a home in which PBDE concentrations are elevated.

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.

Using surveillance data to develop and disseminate local childhood lead poisoning screening recommendations: Miami-Dade County's experience

Before 1999, few children in Florida's Miami-Dade County were being screened for lead poisoning. To improve screening rates, the county's department of health developed screening recommendations and a screening tool using surveillance and census data and disseminated these materials to primary care providers. Each year, recommendations have been reviewed to assess their sensitivity, and revised recommendations have been disseminated to health care providers. The percentage of children 6 years or younger screened in Florida who reside in Miami-Dade County increased from 4.1% in 1998 to 20.3% in 2002. Analysis and dissemination of blood lead surveillance data not only guide development of screening recommendations but also educate health care providers regarding the importance of childhood screening.