Lead contamination in French children's homes and environment

Standards for levels of lead in soil and dust around the world

Lead poisoning is a serious environmental health problem in every country in the world. Exposure to lead results in neurocognitive and behavioral changes, has adverse effects on the immune system, causes anemia, hypertension and perturbs other organ systems. The effects of lead poisoning are most critical for children because their bodies are growing and developing, and particularly because agents that reduce cognitive function and attention span as well as promote disruptive behavior will have life-long consequences. Lead exposure, especially to children, is a major health disparity issue. If the next generation starts with reduced cognitive ability, there will be significant barriers for development of skills and country-wide development. While there are many sources of exposure to lead, the commonest source is lead in soil and dust. Since lead is an element, it does not go away and past releases of lead into the environment remain as soil and dust contamination. This is an especially important route of exposure to children because children regularly play in soil and are exposed via hand-to-mouth activity. In addition to indoor sources of lead, contaminated soil is tracked on shoes or feet and blown by air currents into homes, accumulating in household dust which is a major source of exposure for both children and adults. The purpose of this review is to determine standards presumed to be health protective for lead and dust in different countries. We find that many countries have no standards for lead in soil and dust and rely on standards set by the World Health Organization or the US Environmental Protection Agency, and these standards may or may not be enforced. There is considerable variation in standards set by other countries.

Identifying Sources of Lead Exposure for Children in the Republic of Georgia, with Lead Isotope Ratios

In the Republic of Georgia, a 2018 national survey estimated that more than 40% of children aged 2-7 years had a blood lead concentration (BLC) of more than 5 µg/dL. The objective of this study was to document the feasibility of employing lead isotope ratios (LIRs) to identify and rank the Pb (lead) exposure sources most relevant to children across Georgia. A cross-sectional survey between November 2019 and February 2020 of 36 children previously identified as having BLCs > 5 µg/dL from seven regions of Georgia involved the collection of blood and 528 environmental samples, a questionnaire on behaviours and potential exposures. The LIRs in blood and environmental samples were analysed in individual children and across the whole group to ascertain clustering. A fitted statistical mixed-effect model to LIR data first found that the blood samples clustered with spices, tea, and paint, then, further isotopically distinct from blood were sand, dust, and soil, and lastly, milk, toys, pens, flour, and water. Analysis of the LIRs provided an indication and ranking of the importance of Pb environmental sources as explanatory factors of BLCs across the group of children. The findings support the deployment of interventions aimed at managing the priority sources of exposure in this population.

Characterisation of the risk associated with chronic lifetime exposure to mixture of chemical hazards: case study of trace elements

Risk assessment methodology, mostly commonly used, faces the complexity of the environment. Populations are exposed to multiple sources of chemicals throughout life and the chemical mixtures they are exposed change during time (lifestyle factors, regulatory decisions, etc). The risk assessment needs to consider these dynamics and the evolution of the body with age, in order to refine the exposure assessment to chemicals and to predict the health impact of these exposures. This review highlights the latest methodologies developed to improve risk assessment, especially cor heavy metals. The methodologies aim to better describe the chemical toxicokinetic and toxicodynamic as well as the exposure assessment. Human Biomonitoring (HBM) data give great opportunities to link biomarkers of exposure with an adverse effect. Physiologically-Based Toxicokinetic (PBTK) models are more and more used to simulate the evolution of biomarkers in organisms, considering the external exposures and the physiological evolutions. PBTK models may also be used to determine the routes of exposure or to predict the impacts of schemes of exposure. The major limit is the integration of several chemicals in mixture with common adverse effects and the interactions between them.

Lead in painted surfaces and dusts from rented urban properties (Plymouth, UK)

X-ray fluorescence (XRF) spectrometry has been used to measure lead (Pb) in painted surfaces and indoor dusts from 14 rented properties in the city of Plymouth, UK. Lead was detected in 78 out of 164 surfaces measured (and in 69 out of 150 interior surfaces) with an overall median concentration of 7100 mg kg^-1 (range from 157 to 139,000 mg kg^-1), and was detected in all but two properties that included one building constructed within the last 25 years. Selected measurements on an area basis (n = 48) returned Pb concentrations ranging from below 0.01 to 16.1 mg cm^-2 that were significantly correlated with concentrations on a mass basis but with scatter that was attributed to the degree to which leaded paint had been overpainted. As potential measures of Pb exposure, mean concentrations in samples of lint (n = 8) were <15 mg kg^-1 while mean concentrations in hoovered dusts (n = 14) were more variable; specifically, mean Pb dust concentrations ranged from ∼20 to 140 mg kg^-1 in 13 samples but was ∼4500 mg kg^-1 in a property that had recently undergone extensive renovation. Although mean concentrations of Pb in lint or dust were not related to median Pb concentrations in paint, a strong correlation between barium (Ba) and Pb in dusts suggests that paint is the main source of dust Pb. This study indicates that, in most cases, leaded paints historically applied to interior surfaces have been over-coated and pose little risk, provided that surface coatings are in good condition. However, inappropriate practices during renovation can result in significant contamination of dusts. Our findings are likely to be more broadly applicable to the urban rented sector in the UK and landlords and tenants should, therefore, be made aware of government guidance on the safe decoration or remodelling of older properties where leaded paint is pervasive.

Lead and chromium in European road paints

Lead chromate was commonly employed as a pigment in coloured road markings until restrictions led to the development of safer alternatives. In this study, the presence and concentrations of Pb and Cr have been determined in 236 road paints of various colours sampled from streets, highways, footways and carparks from eleven European countries. According to energy-dispersive X-ray fluorescence spectrometry, Pb was detected (>10 mg kg^-1) in 148 samples at concentrations up to 17.2% by weight, and above 1000 mg kg^-1 yellow was the dominant paint colour. Lead concentrations on an area basis varied from 0.02 to 8.46 mg cm^-2 and the metal was located at different depths amongst the samples, suggesting that formulations had been painted both recently and historically (and overpainted). Chromium was detected (>5 to 50 mg kg^-1) in 81 samples at concentrations between 20 and 20,000 mg kg^-1 and most often in yellow paints, and concentrations co-varied with those of Pb. These observations, and results of scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, suggested that heterogeneously dispersed PbCrO₄ was the dominant, but not the only, Pb-based pigment in the samples. Although there were significant international differences in frequency of Pb detection and median Pb concentrations, overall, and despite various, albeit complex, regulations, recent or extant road paint pigmented with Pb and Cr remains a pervasive environmental problem and a potential health risk in many European countries.

On the Role of Atmospheric Weathering on Paint Dust Aerosol Generated by Mechanical Abrasion of TiO2 Containing Paints

In recent years, the introduction and use of new nanomaterials in construction has increased at a rapid rate. Exterior surface paints have been a product that have had these nanomaterials added to them. In this study, the effects of natural weathering and exposure to atmospheric agents was examined to determine the detrimental effects on outdoor paint that has been created with nanomaterials. Data collected over the course of the yearlong study indicate that the nanoparticles of the titanium dioxide were eliminated rapidly. Further testing indicated that various elements of weathering were affecting the physical integrity of the paint. The weathering agents that appeared to have the greatest effect on the samples were acid deposition and total precipitation. There was a strong association between carbon monoxide and the effects on the panels. These results can lead to new plans for assessments involving the synergistic effects of all weathering agents.

Contamination and Potential Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metals in House Settled Dust Collected from Residences of Young Children

House settled dust (HSD) contains various hazardous materials, including polycyclic aromatic hydrocarbons (PAHs) and metals. Exposure to toxicants contained in HSD is of paramount concern especially in the case of young children, due to their particular behavioral characteristics. In this context, extracts of sieved vacuum cleaner dust from 20 residences with young children were examined for the presence of PAHs and trace metals, in Athens, Greece. The results indicated that PAHs and metals were ubiquitous in the studied residences. The calculated enrichment factors (EF) of trace metals indicated that Cu, Se, Zn, Hg, Cd, and Pb were mainly of anthropogenic. According to the PCA analysis, the main sources of household dust were: smoking inside the houses, combustion processes, resuspension of soil dust, and vehicle traffic. In general, the cancer risk due to PAHs exposure was found lower than the threshold value. The ingestion of house dust was the most important route of exposure to metals. The dose of almost all elements for the children was found 1–2 orders of magnitude lower than the corresponding reference values. Both the carcinogenic and noncarcinogenic risks of exposure were within the safety limits.

Long-term time trend of lead exposure in young German adults - Evaluation of more than 35 Years of data of the German Environmental Specimen Bank

Lead is a ubiquitous pollutant with well-known effects on human health. As there is no lower toxicological threshold for lead in blood and since data gaps on lead exposure still exist in many European countries, HBM data on lead is of high importance. To address this, the European Human Biomonitoring Initiative HBM4EU classified lead as a priority substance. The German Environmental Specimen Bank (German ESB) has monitored lead exposure since more than 35 years. Using data from the early 1980s to 2019 we reveal and discuss long-term trends in blood lead levels (BLLs) and current internal exposure of young adults in Germany. BLLs in young adults decreased substantially in the investigated period. As results from the ESB sampling site Muenster demonstrate, the geometric mean of BLLs of young adults decreased from 1981 (78,7 μg/L) to 2019 (10.4 μg/L) by about 87%. Trends in human exposure closely correlate with air lead levels (ALLs) provided by the European Monitoring and Evaluation Programme (EMEP). Hence, the decrease of BLLs largely reflects the drop in air lead pollution. Known associations of sex, smoking, alcohol consumption, and housing situation with BLLs are confirmed with data of the German ESB. Although internal lead exposure in Germany decreased substantially, the situation might be different in other European countries. Since 2010, BLLs of young adults in Germany levelled out at approximately 10 μg/L. The toxicity of lead even at low levels is known to cause adverse health effects especially in children following exposure of the child or the mother during pregnancy. To identify current exposure sources and to minimize future lead exposure, continuous monitoring of lead intake and exposure levels is needed.

Combining data from heterogeneous surveys for aggregate exposure: Application to children exposure to lead in France

To assess human health risks related to the environment, it is necessary to aggregate exposure from multiple sources. The objective of this paper was to propose a relevant approach to combine data from heterogeneous populations and methodologies. Five different methods based on Monte-Carlo simulations were tested and compared. Differences were: taking into account or not stratification variable, timeline to assign exposure factors and concentration and way to account for concentration correlations. The methods were applied to estimate lead exposure from food, dust, soil, air, and tap water or French children aged between six months and three years old. Comparing results' uncertainty, it is recommended to 1) select a reference population representative of the target population, 2) select stratification variables to combine surveys, and 3) simulate a new population by randomly sampling individuals in the reference population and simultaneously assigning human exposure factors and environmental concentrations from other surveys in integrating correlations (MC1S). No difference was observed when taking into account correlations using vectors of determinist data from one survey or rank of correlations with the Iman-Conover method. Regardless the methods used to combine data, dust was the main exposure source, followed by soil and in a less extent by food. Exposures from air and tap water were found to be insignificant for most children.

Removal and tolerance mechanism of Pb by a filamentous fungus: A case study

Currently, Pb pollution has become a severe environmental problem and filamentous fungi hold a promising potential for the treatment of Pb-containing wastewater. The present study showed that the strain Pleurotus ostreatus ISS-1 had a strong ability to tolerate Pb at high concentration and reached a removal rate of 53.7% in liquid media. Pb was removed by extracellular biosorption, intracellular bioaccumulation by mycelia, or precipitation with extracellular oxalic acids. On the cellular level, Pb was mainly distributed in the cell wall, followed by vacuoles and organelles. Fourier transform infrared spectroscopy (FTIR) analysis indicated that hydroxyl, amides, carboxyl, and sulfhydryl groups provided binding sites for Pb. Furthermore, Pb was found on the cell surface in the form of PbS and PbCO₃ through X-ray diffraction (XRD). Intracellular chelates such as thiol compounds and oxalic acid, as well as extracellular oxalic acid, might play an important role in the tolerance of Pb. In addition, isobaric tags for relative and absolute quantitation (iTRAQ) analysis showed that ATP-binding cassette (ABC) transporter, cytochrome P450, peroxisome, and the calcium signaling pathway might participate in both accumulation and detoxification of Pb. These results have successfully provided a basis for further developing Pb polluted water treatment technology by fungi.

Lead-based paint remains a major public health concern: A critical review of global production, trade, use, exposure, health risk, and implications

Human exposure to lead (Pb) is a growing global public health concern. Elevated blood lead is thought to cause the mental retardation of >0.6 million children globally each year, and has recently been attributed to ~18% of all-cause mortality in the US. Due to the severe health risk, the international community, led by the United Nations Environment Programme (UNEP) and the World Health Organization (WHO), is actively supporting the global phase-out of lead-based paint by 2020. However, there are many significant hurdles on the way to achieving this goal. In light of the importance of the lead-based paint issue, and the urgency of achieving the 2020 phase-out goal, this review provides critical insights from the existing scientific literature on lead-based paint, and offers a comprehensive perspective on the overall issue. The global production and international trade of lead-based paints across Asia, Africa, Latin America, and Europe are critically discussed - revealing that lead-based paints are still widely used in many low and middle-income developing countries, and that the production and trade of lead-based paint is still wide-spread globally. In India, as well as many south-east Asian, African, Latin American and European countries, lead concentrations in paints often exceed 10,000 mg/kg. This will certainly pose a serious global threat to public health from surfaces painted with these products for many decades to come. The sources and pathways of exposure are further described to shed light on the associated health risk and socioeconomic costs. Finally, the review offers an overview of the potential intervention and abatement strategies for lead-based paints. In particular, it was found that there is a general lack of consensus on the definition of lead based paint; and, strengthening regulatory oversight, public awareness, and industry acceptance are vital in combating the global issue of lead based paint.

Comparison of tolerance and biosorption of three trace metals (Cd, Cu, Pb) by the soil fungus Absidia cylindrospora

Trace metals cause deterioration of the soil and constitute a major concern for the environment and human health. Bioremediation could be an effective solution for the rectification of contaminated soils. Fungi could play an important role in biodegradation because of the morphology of their mycelium (highly reactive and extensive biological surface) and its physiology (high tolerance to many stresses, production of enzymes and secondary metabolites). Fungi can effectively biosequestrate, or biotransform many organic and inorganic contaminants into a non-bioavailable form. This experiment was designed to evaluate the tolerance and the biosorption abilities of the fungus Absidia cylindrospora against three trace metals: Cadmium (Cd), Copper (Cu), and Lead (Pb). Firstly, the tolerance of the strain was evaluated on metal-enriched malt extract agar (MEA). Secondly, the strain was exposed to trace metals, in a liquid malt extract medium. After 3 or 7 days of exposure, the quantities of absorbed and adsorbed metals were measured with Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Biomass production and pH evolution were also evaluated during the test. Our experiment revealed differences between the three metals. In agar medium, Cd and Pb were better tolerated than Cu. In liquid medium, Cd and Pb were mostly absorbed whereas Cu was mostly adsorbed. A. cylindrospora biosorbed 14% of Cu, 59% of Pb and 68% of Cd when exposed for 3 days at 50 mg L^-1.

Outdoor and indoor particle characterization from a large and uncontrolled combustion of a tire landfill

A large and uncontrolled fire of a tire landfill started in Seseña (Toledo, Spain) on May 13, 2016. An experimental deployment was immediately launched in the area for measuring regulated and non-standard air quality parameters to assess the potential impact of the plume at local and regional levels. Outdoor and indoor measurements of different parameters were carried out at a near school, approximately 700m downwind the burning tires. Real time measurements of ambient black carbon (BC) and total number particle concentrations were identified as good tracers of the smoke plume. Simultaneous peaks allowed us to characterize situations of the plume impact on the site. Outdoor total particle number concentrations reached in these occasions 3.8×10⁵particlescm^-3 (on a 10min resolution) whereas the indoor concentration was one order of magnitude lower. BC mass concentrations in ambient air were in the range of 2 to 7μgm^-3, whereas concentrations<2μgm^-3 were measured indoor. Indoor and outdoor deposited inhalable dust was sampled and chemically characterized. Both indoor and outdoor dust was enriched in tire components (Zn, sulfate) and PAHs associated to the tire combustion process. Infiltration processes have been documented for BC and particle number concentrations causing increases in indoor concentrations.

Environmental and dietary exposure of young children to inorganic trace elements

Children are exposed to toxic metals and metalloids via their diet and environment. Our objective was to assess the aggregate chronic exposure of children aged 3-6years, living in France, to As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V present in diet, tap water, air, soil and floor dust in the years 2007-2009. Dietary data came from the French Total Diet Study, while concentrations in residential tap water, soil and indoor floor dust came from the 'Plomb-Habitat' nationwide representative survey on children's lead exposure at home. Indoor air concentrations were assumed to be equal to outdoor air concentrations, which were retrieved from regulatory measurements networks. Human exposure factors were retrieved from literature. Data were combined with Monte Carlo simulations. Median exposures were 1.7, 0.3, 10.2, 34.1, 60.3, 0.7, 0.1, 44.3, 1.5 and 95th percentiles were 4.4, 0.5, 15.8, 61.3, 98.3, 2.5, 0.1, 111.1, 2.9μg/kgbw/d for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. Dietary exposures dominate aggregate exposures, with the notable exception of Pb - for which soils and indoor floor dust ingestion contribute most at the 95th percentile. The strengths of this study are that it aggregates exposures that are often estimated separately, and uses a large amount of representative data. This assessment is limited to main diet and residential exposure, and does not take into account the relative bioavailability of compounds. These results could be used to help target prevention strategies.

Exposure of children to metals via tap water ingestion at home: Contamination and exposure data from a nationwide survey in France

29 inorganic compounds (Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, Gd, K, Mg, Mn, Mo, Na, Nd, Ni, Pb, Sb, Se, Sr, Tl, U, V and Zn) were measured in the tap water of 484 representative homes of children aged 6months to 6years in metropolitan France in 2008-2009. Parents were asked whether their children consumed tap water. Sampling design and sampling weights were taken into account to estimate element concentrations in tap water supplied to the 3,581,991 homes of 4,923,058 children aged 6months to 6years. Median and 95th percentiles of concentrations in tap water were in μg/L: Al: <10, 48.3, As: 0.2, 2.1; B: <100, 100; Ba: 30.7, 149.4; Ca: 85,000, 121,700; Cd: <0.5, <0.5; Ce: <0.5, <0.5; Co: <0.5, 0.8; Cr: <5, <5; Cu: 70, 720; K: 2210, 6740; Fe: <20, 46; Mn: <5, <5; Mo: <0.5, 1.5; Na: 14,500, 66,800; Ni: <2, 10.2; Mg: 6500, 21,200; Pb: <1, 5.4; Sb: <0.5, <0.5; Se: <1, 6.7; Sr: 256.9, 1004; Tl: <0.5, <0.5; U: <0.5, 2.4; V: <1, 1; Zn: 53, 208. Of the 2,977,123 young children drinking tap water in France, some were drinking water having concentrations above the 2011 World Health Organization drinking-water quality guidelines: respectively 498 (CI 95%: 0-1484) over 700μg/L of Ba; 121,581 (CI 95%: 7091-236,070) over 50mg/L of Na; 2044 (CI 95%: 0-6132) over 70μg/L of Ni, and 78,466 (17,171-139,761) over 10μg/L of Pb. Since it is representative, this tap water contamination data can be used for integrated exposure assessment, in conjunction with diet and environmental (dust and soil) exposure data.

Screening for Elevated Blood Lead Levels in Children: Assessment of Criteria and a Proposal for New Ones in France

The decline in children’s Blood Lead Levels (BLL) raises questions about the ability of current lead poisoning screening criteria to identify those children most exposed. The objectives of the study were to evaluate the performance of current screening criteria in identifying children with blood lead levels higher than 50 µg/L in France, and to propose new criteria. Data from a national French survey, conducted among 3831 children aged 6 months to 6 years in 2008–2009 were used. The sensitivity and specificity of the current criteria in predicting blood lead levels higher than or equal to 50 µg/L were evaluated. Two predictive models of BLL above 44 µg/L (for lack of sufficient sample size at 50 µg/L) were built: the first using current criteria, and the second using newly identified risk factors. For each model, performance was studied by calculating the area under the ROC (Receiver Operating Characteristic) curve. The sensitivity of current criteria for detecting BLL higher than or equal to 50 µg/L was 0.51 (0.26; 0.75) and specificity was 0.66 (0.62; 0.70). The new model included the following criteria: foreign child newly arrived in France, mother born abroad, consumption of tap water in the presence of lead pipes, pre-1949 housing, period of construction of housing unknown, presence of peeling paint, parental smoking at home, occupancy rates for housing and child’s address in a cadastral municipality or census block comprising more than 6% of housing that is potentially unfit and built pre-1949. The area under the ROC curve was 0.86 for the new model, versus 0.76 for the current one. The lead poisoning screening criteria should be updated. The risk of industrial, occupational and hobby-related exposure could not be assessed in this study, but should be kept as screening criteria.

Environmental determinants of different blood lead levels in children: a quantile analysis from a nationwide survey

Blood lead levels (BLLs) have substantially decreased in recent decades in children in France. However, further reducing exposure is a public health goal because there is no clear toxicological threshold. The identification of the environmental determinants of BLLs as well as risk factors associated with high BLLs is important to update prevention strategies. We aimed to estimate the contribution of environmental sources of lead to different BLLs in children in France. We enrolled 484 children aged from 6months to 6years, in a nationwide cross-sectional survey in 2008-2009. We measured lead concentrations in blood and environmental samples (water, soils, household settled dusts, paints, cosmetics and traditional cookware). We performed two models: a multivariate generalized additive model on the geometric mean (GM), and a quantile regression model on the 10th, 25th, 50th, 75th and 90th quantile of BLLs. The GM of BLLs was 13.8μg/L (=1.38μg/dL) (95% confidence intervals (CI): 12.7-14.9) and the 90th quantile was 25.7μg/L (CI: 24.2-29.5). Household and common area dust, tap water, interior paint, ceramic cookware, traditional cosmetics, playground soil and dust, and environmental tobacco smoke were associated with the GM of BLLs. Household dust and tap water made the largest contributions to both the GM and the 90th quantile of BLLs. The concentration of lead in dust was positively correlated with all quantiles of BLLs even at low concentrations. Lead concentrations in tap water above 5μg/L were also positively correlated with the GM, 75th and 90th quantiles of BLLs in children drinking tap water. Preventative actions must target household settled dust and tap water to reduce the BLLs of children in France. The use of traditional cosmetics should be avoided whereas ceramic cookware should be limited to decorative purposes.

An exposure-based framework for grouping pollutants for a cumulative risk assessment approach: case study of indoor semi-volatile organic compounds

Humans are exposed to a large number of contaminants, many of which may have similar health effects. This paper presents a framework for identifying pollutants to be included in a cumulative risk assessment approach. To account for the possibility of simultaneous exposure to chemicals with common toxic modes of action, the first step of the traditional risk assessment process, i.e. hazard identification, is structured in three sub-steps: (1a) Identification of pollutants people are exposed to, (1b) identification of effects and mechanisms of action of these pollutants, (1c) grouping of pollutants according to similarity of their mechanism of action and health effects. Based on this exposure-based grouping we can derive "multi-pollutant" toxicity reference values, in the "dose-response assessment" step. The approach proposed in this work is original in that it is based on real exposures instead of a limited number of pollutants from a unique chemical family, as traditionally performed. This framework is illustrated by the case study of semi-volatile organic compounds in French dwellings, providing insights into practical considerations regarding the accuracy of the available toxicological information. This case study illustrates the value of the exposure-based approach as opposed to the traditional cumulative framework, in which chemicals with similar health effects were not always included in the same chemical class.

Blood lead levels and risk factors in young children in France, 2008-2009

BACKGROUND

The exposure of children to lead has decreased in recent years, thanks notably to the banning of leaded gasoline. However, lead exposure remains a matter of public health concern, because no toxicity threshold has been observed, cognitive effects having been demonstrated even at low levels. It is therefore important to update exposure assessments. A national study was conducted, in 2008-2009, to determine the blood lead level (BLL) distribution in children between the ages of six months and six years in France. We also assessed the contribution of environmental factors.

METHODS

This cross-sectional survey included 3831 children recruited at hospitals. Two-stage probability sampling was carried out, with stratification by hospital and French region. Sociodemographic characteristics were recorded, and blood samples and environmental data were collected by questionnaire. Generalized linear model and quantile regression were used to quantify the association between BLL and environmental risk factors.

RESULTS

The geometric mean BLL was 14.9μg/l (95% confidence interval (CI)=[14.5-15.4]) and 0.09% of the children (95% CI=[0.03-0.15]) had BLLs exceeding 100μg/l, 1.5% (95% CI=[0.9-2.1] exceeding 50μg/l. Only slight differences were observed between French regions. Environmental factors significantly associated with BLL were the consumption of tap water in homes with lead service connections, peeling paint or recent renovations in old housing, hand-mouth behavior, passive smoking and having a mother born in a country where lead is often used.

CONCLUSIONS

In children between the ages of one and six years in France, lead exposure has decreased over the last 15 years as in the US and other European countries. Nevertheless still 76,000 children have BLL over 50μg/l and prevention policies must be pursued, especially keeping in mind there is no known toxicity threshold.

Measurements of semi-volatile organic compounds in settled dust: influence of storage temperature and duration

Indoor dust samples cannot always be analyzed immediately after collection. However, little information is currently available on how storage conditions may affect measurements. This study was designed to determine how sample storage conditions may affect the concentration of semi-volatile organic compounds (SVOCs) in the dust. A composite dust was prepared using a Standard Reference Material (SRM 2585) with real indoor dust samples. The composite dust was stored in various types of packaging, at different temperatures (-18°C, 5°C, 20°C, and 35°C), and in different light conditions. The concentration of SVOCs was measured after various storage durations. No effect on SVOC concentrations was observed for the composite dust stored in an amber glass vial at -18°C for 36 months. At 5°C, 20°C, and 35°C, losses occurred for the more volatile compounds. The experimental storage conditions clearly showed that temperature and duration affected the concentrations of SVOCs in the composite dust. The type of packaging material (polyethylene zip bag or polyethylene garbage bag) did not seem to have a systematic effect on the preservation of SVOCs in the composite dust. Maximum storage duration times are proposed for each compound at various temperatures. For most compounds, samples can be stored for 2 months at 20°C. For samples that cannot be analyzed immediately, we recommend to store them in the dark at -18°C to ensure a good recovery of all tested compounds.

Source contributions of lead in residential floor dust and within-home variability of dust lead loading

Evidence of the impact of exposure to low levels of lead on children's health is increasing. Residential floor dust is the assumed origin of lead exposure by young children. In this study, we estimate the contribution of different lead sources to household interior floor dust contamination. We also estimate the within-home variability of interior floor dust lead loadings. A multilevel model was developed based on data collected in a French survey in 2008-2009 (484 housing units, 1834 rooms). Missing data were handled by multiple imputation using chained equations. The intra-home correlation between interior floor Log dust lead loadings was approximately 0.6. Dust lead from the landing of an apartment, mostly originating outside the building, was the major contributor to interior floor dust lead. Secondary contributors included the lead-based paint on exterior railings, track-in of the exterior soil of the children's play area into the dwelling, smoking inside the home, demolition of nearby old buildings and sites of pollution in the vicinity. Interior lead-based paint contaminated interior floor dust only in old and non-renovated dwellings. To reduce interior floor dust lead levels in the general population of dwellings, common areas should be maintained, and track-in from the outside should be limited as much as possible.

Human biomonitoring issues related to lead exposure

Lead as a toxic environmental metal has been an issue of concern for 30-40 years. Even though the exposures experienced by the general public have been significantly reduced, so have the acceptable blood lead concentrations assessed to safeguard health (specifically of children). The impact of these concurrent changes are reviewed and discussed in terms of the following: blood lead as the primary biomarker of exposure; pertinent toxicokinetic issues including modelling; legacy and newer sources of this toxic metal; improvements in lead quantification techniques and its characterization (chemical forms) in exposure media; and in vivo markers of lead sources. It is concluded that the progress in the quantification of lead and its characterization in exposure media have supported the efforts to identify statistical associations of lead in blood and tissues with adverse health outcomes, and have guided strategies to reduce human exposure (especially for children). To clarify the role of lead as a causative factor in disease, greater research efforts in biomarkers of effect and susceptibility seem timely.

Implications of different residential lead standards on children's blood lead levels in France: predictions based on a national cross-sectional survey

Despite the dramatic reductions in children's blood lead levels (BLLs), there is considerable evidence that low-level lead exposure is associated with intellectual deficits and behavioral problems, without apparent threshold. There are limited data, however, about the contribution of residential sources of lead to contemporary children's blood lead levels. The aim of this study is to calculate the contributions of residential sources of lead to assess the potential impact of setting new standards for lead levels in residential dust, soil and water. We enrolled 484 French children aged from 6 months to 6 years, and collected data on social, housing and individual characteristics. Lead concentrations in blood and environmental samples (water, soils, and dusts) were measured using inductively coupled plasma mass spectrometry. Data were analyzed using a multivariate generalized additive model accounting for the sampling design and the sampling weights. We found that exceedingly low concentrations of lead in dust, soil and water were significant predictors of children's BLLs, after adjustment for potential confounding variables. Lead-contaminated floor dust was the main source of lead in blood. BLLs (GM: 14μg/L) increased by 65%, 13%, 25%, and 5% when lead content in floor dust, loose soil, hard soil and water increased from their 25th percentile to their 95th percentile, respectively. We also observed that the steepest increase in BLLs occurred at the lowest levels of lead-contaminated floor dust, which indicates that lead contamination should be kept as low as possible. Impact of different possible standards on children's BLLs was also tabulated and indicated that unless standards are set low, they will only benefit a small proportion of children who have the highest exposures.

French children's exposure to metals via ingestion of indoor dust, outdoor playground dust and soil: contamination data

In addition to dietary exposure, children are exposed to metals via ingestion of soils and indoor dust, contaminated by natural or anthropogenic outdoor and indoor sources. The objective of this nationwide study was to assess metal contamination of soils and dust which young French children are exposed to. A sample of 484 children (6 months to 6 years) was constituted in order to obtain representative results for young French children. In each home indoor settled dust was sampled by a wipe in up to five rooms. Outdoor playgrounds were sampled with a soil sample ring (n=315) or with a wipe in case of hard surfaces (n=53). As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V were measured because of their potential health concern due to soil and dust ingestion. The samples were digested with hydrochloric acid, and afterwards aqua regia in order to determine both leachable and total metal concentrations and loadings by mass spectrometry with a quadrupole ICP-MS. In indoor settled dust most (total) loadings were below the Limit of Quantification (LOQ), except for Pb and Sr, whose median loadings were respectively 9 and 10 μg/m². The 95th percentile of loadings were 2 μg/m² for As, <0.8 for Cd, 18 for Cr, 49 for Cu, <64 for Mn, 63 for Pb, 2 for Sb, 56 for Sr, and <8 for V. Median/95th percentile of loadings in settled dust on outdoor playgrounds were 2/16, <0.8/1.3, 17/53, 49/330, 99/424, 32/393, 2/13, 86/661 and 10/37 μg/m² for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. In outdoor playground soil median/95th percentile of concentrations (μg/g) were 8/26, <0.65/1, 25/52, <26/53,391/956, 27/254, 0.7/4, 54/295, 23/57 for As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V respectively. These results are comparable with those observed in other countries. Because of their representative nature, we can assess children's exposures to these metals via soil and dust and the associated risks in urban and rural environments. Ratios of leachable/total concentrations and loadings, calculated on >LOQ measurements, differed among metals. To a lesser extent, they were also affected by type of matrix, with (except for Cd) a greater leachability of dust (especially indoor) compared to soils.