Children's Lead Concentrations Research Articles

Children’s Blood Lead: Ethnic Differences in Home Cleaning Practice in Seri Serdang, Selangor, Malaysia

This was a cross-sectional study aimed at determining the association between blood lead concentrations in the children below 4 years old with the ethnic differences in home cleaning practices in Seri Serdang housing area. Sixty children from the study area were chosen using purposive sampling technique. About 55% of the total respondents were Malay while 45% of the respondents were Indian children. Blood samples were collected from the children using heel-prick method and were analyzed by using Graphite Furnace Atomic Absorption Spectrometer Model GBC 908AA (GFAAS). Home cleaning practices included frequency of sweeping, mopping, cleaning and vacuuming. Indoor dust samples were collected with NIOSH surface wipe sampling methods (1996) using the moistened tissue sized 10cm × 10cm. Indoor dust concentration was calculated using gravimetric technique. The dust lead was analyzed using GFAAS according to NIOSH Analytical Methods (1996). The mean value and standard deviations for the blood lead were 4.52 ± 0.64 ug/dl, indoor dust level 320.8 ± 143.2 g/m2 and indoor dust lead ranges from 6.53 × 10−4 ng/g/m2 to 3.94x10−1 ng/g/m2. Blood lead concentration of these children was not significantly correlated with ethnic (r=−0.013, p=0.403) and home cleaning practices, frequency of sweeping (r=−0.130, p=0.320), mopping (r=−0.033, p=0.800), cleaning (r=−0.065, p=0.619) and vacuuming (r=−0.185, p=0.158). But the indoor dust was significantly correlated with dust lead level (r=−0.432, p=0.001). There was also significance correlation between dust lead level with blood lead concentration (r=0.361, p=0.005) and home cleaning practices such as frequency of sweeping (r=−0.329, p=0.010) and mopping (r=−0.257, p=0.047). In conclusion, ethnicity and home cleaning practices did not influence the blood lead concentration in children but the indoor dust contamination contributed to high dust lead concentration.

Use of the IEUBK Model for Determination of Exposure Routes in View of Site Remediation

ABSTRACT The Integrated Exposure Uptake Biokinetic (IEUBK) model is frequently used to estimate blood lead concentrations of children exposed to lead. Simulations with the IEUBK model were run to estimate the blood lead concentration in children living in the vicinity of a non-ferrous plant, situated in Hoboken, Belgium. Concentrations in soil ranged from 59–2425 mg Pb/kg dm, average concentrations in house dust ranged from 234–73394 mg Pb/kg dm. Measured blood lead concentrations in children aged 2–7 years were between 3 and 35 μ g/dl. Exposure sources were indoor dust in the house and the school, outdoor dust and soil in the home surrounding and at the school's playground, and suspended dust in the air. Soil ingestion values and lead exposure from food were changed to Flemish values. The model was able to predict the measured blood lead concentrations adequately except for the lowest exposure group. Predictions showed a systematic overestimation. Analysis of the data revealed that the neighbourhood's school is an important source of exposure to lead; indoor house dust dominates exposure for children going to school outside the area, because of the high concentrations of lead in indoor dust (3 to 5 times higher than in outdoor soil).

Iron and/or Zinc Supplementation Did Not Reduce Blood Lead Concentrations in Children in a Randomized, Placebo-Controlled Trial

There is increasing interest in the interaction of nutritional deficiencies with toxic metals. Iron deficiency and elevated blood lead concentrations (PbB) reportedly occur together, and zinc also plays an important role in lead metabolism. The objective was to evaluate the effect of zinc and/or iron supplementation on PbB of children attending schools in the neighborhood of a smelter complex for 6 mo. We conducted a double-blind, placebo-controlled field trial in 9 elementary schools located within a 3.5-km radius of a metal foundry in Torreón, Mexico. Of the 602 first-graders enrolled, 517 completed supplementation and had initial and final PbBs. Children were given either 30 mg of iron, 30 mg of zinc, both, or a placebo daily for 6 mo. Baseline and final measures included nutritional status and PbB. The overall prevalence of iron and zinc deficiencies was 12.1 and 30.3%, respectively, and 10.3% were anemic. The PbB concentration decreased in all experimental groups (P < 0.05). After controlling for initial PbB, groups administered zinc and/or iron did not have lower PbB concentrations than the placebo group (P < 0.05). In conclusion, iron supplementation of lead-exposed children significantly improved iron status but did not reduce PbBs. Zinc supplementation did not reduce PbBs independently of zinc nutritional status. Neither iron nor zinc can be recommended as the sole treatment for lead-exposed school children.

Hypothesis Decay?: Blood Lead–Fluoridation Link Not Confirmed

Vol. 114, No. 1 EnvironewsOpen AccessHypothesis Decay?: Blood Lead–Fluoridation Link Not Confirmedis accompanied byBlood Lead Concentrations in Children and Method of Water Fluoridation in the United States, 1988–1994 John Tibbetts John Tibbetts Search for more papers by this author Published:1 January 2006https://doi.org/10.1289/ehp.114-a49AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Numerous studies of various populations have shown that adding fluoride to drinking water prevents dental decay. However, a 1999 study in Massachusetts and a 2000 study in New York reported associations between the use of silicofluoride compounds in community water systems and elevated blood lead (PbB) concentrations in children. Now a team of researchers has tested the hypothesis generated by the Massachusetts and New York studies against findings from two other studies and found no cause for concern [EHP 114:130–134].As of 2000, the Centers for Disease Control and Prevention estimated that more than 162 million Americans were receiving fluoridated water. In the United States, several agents are used for fluoridation, including silicofluoride compounds (sodium silicofluoride and hydrofluosilicic acid) and sodium fluoride. Researchers with the Massachusetts and New York studies hypothesized that the silicofluoride compounds in tap water might enhance lead leaching from pipes and increase lead absorption from the water itself. Elevated PbB concentrations in children are associated with a host of cognitive, developmental, and behavioral impairments so serious that lead-based paint was banned in the United States in 1978 and lead water pipe solder was banned in the 1980s.The current research group evaluated the relationship between water fluoridation method and PbB concentrations in children by conducting a large-scale statistical analysis of two other preexisting studies: the 1992 Fluoridation Census and the Third National Health and Nutrition Examination Survey (NHANES III). In analyzing data from NHANES III and the 1992 Fluoridation Census, the team improved on prior analyses by log-transforming raw PbB concentration and by including information on possible confounding factors missing from the Massachusetts and New York studies. These included poverty status, urbanicity, duration of residence, and year in which the dwelling was built.The NHANES III sample was comprehensive, representing more than 52 million U.S. children. This survey also oversampled young children, older adults, non-Hispanic blacks, and Mexican Americans to ensure that population estimates for these groups would be statistically reliable.The team found that, overall, the PbB concentrations of children who lived in counties receiving silicofluorides did not differ significantly from the PbB concentrations of children living in counties without fluoridated water. This was true even when researchers controlled for the year in which children’s homes were built. Given these findings, the team states there is no support for concerns that silicofluorides in community water systems cause higher PbB concentrations in children.However, the investigators acknowledge that their analysis has limitations. For example, NHANES III did not measure the lead content of drinking water consumed by study participants. Also, the team did not control for factors such as density of older housing, and they were unable to control for the solubility of lead in pipes affected by different temperatures and water hardness.Because of these limitations, the investigators cannot completely rule out a link between water fluoridation method and lead uptake in children, particularly in children living in older dwellings. They speculate that other studies, possibly those including chemical investigation and animal toxicology, could yield additional valuable data. They conclude that efforts to prevent dental decay via the use of fluoridated drinking water should continue unless a causal effect of specific fluoridation methods on PbB concentration is demonstrated by additional research.Refreshing news.Although some questions remain, a new data analysis fails to confirm fears that fluoridation of drinking water results in higher blood lead along with stronger teeth.FiguresReferencesRelatedDetailsRelated articlesBlood Lead Concentrations in Children and Method of Water Fluoridation in the United States, 1988–199417 August 2005Environmental Health Perspectives Vol. 114, No. 1 January 2006Metrics About Article Metrics Publication History Originally published1 January 2006Published in print1 January 2006 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. 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Blood Lead Concentrations in Children and Method of Water Fluoridation in the United States, 1988–1994

Some have hypothesized that community water containing sodium silicofluoride and hydrofluosilicic acid may increase blood lead (PbB) concentrations in children by leaching of lead from water conduits and by increasing absorption of lead from water. Our analysis aimed to evaluate the relation between water fluoridation method and PbB concentrations in children. We used PbB concentration data (n = 9,477) from the Third National Health and Nutrition Examination Survey (1988–1994) for children 1–16 years of age, merged with water fluoridation data from the 1992 Fluoridation Census. The main outcome measure was geometric mean PbB concentration, and covariates included age, sex, race/ethnicity, poverty status, urbanicity, and length of time living in residence. Geometric mean PbB concentrations for each water fluoridation method were 2.40 μg/dL (sodium silicofluoride), 2.34 μg/dL (hydrofluosilicic acid), 1.78 μg/dL (sodium fluoride), 2.24 μg/dL (natural fluoride and no fluoride), and 2.14 μg/dL (unknown/mixed status). In multiple linear and logistic regression, there was a statistical interaction between water fluoridation method and year in which dwelling was built. Controlling for covariates, water fluoridation method was significant only in the models that included dwellings built before 1946 and dwellings of unknown age. Across stratum-specific models for dwellings of known age, neither hydrofluosilicic acid nor sodium silicofluoride were associated with higher geometric mean PbB concentrations or prevalence values. Given these findings, our analyses, though not definitive, do not support concerns that silicofluorides in community water systems cause higher PbB concentrations in children. Current evidence does not provide a basis for changing water fluoridation practices, which have a clear public health benefit.

Risks to children from exposure to lead in air during remedial or removal activities at Superfund sites: a case study of the RSR lead smelter Superfund site.

Superfund sites that are contaminated with lead and undergoing remedial action generate lead-enriched dust that can be released into the air. Activities that can emit lead-enriched dust include demolition of lead smelter buildings, stacks, and baghouses; on-site traffic of heavy construction vehicles; and excavation of soil. Typically, air monitoring stations are placed around the perimeter of a site of an ongoing remediation to monitor air lead concentrations that might result from site emissions. The National Ambient Air Quality (NAAQ) standard, established in 1978 to be a quarterly average of 1.5 microg/m(3), is often used as a trigger level for corrective action to reduce emissions. This study explored modeling approaches for assessing potential risks to children from air lead emissions from the RSR Superfund site in West Dallas, TX, during demolition and removal of a smelter facility. The EPA Integrated Exposure Uptake Biokinetic (IEUBK) model and the International Commission of Radiologic Protection (ICRP) lead model were used to simulate blood lead concentrations in children, based on monitored air lead concentrations. Although air lead concentrations at monitoring stations located in the downwind community intermittently exceeded the NAAQ standard, both models indicated that exposures to children in the community areas did not pose a significant long-term or acute risk. Long-term risk was defined as greater than 5% probability of a child having a long-term blood lead concentration that exceeded 10 microg/dl, which is the CDC and the EPA blood lead concern level. Short-term or acute risk was defined as greater than 5% probability of a child having a blood lead concentration on any given day that exceeded 20 microg/dl, which is the CDC trigger level for medical evaluation (this is not intended to imply that 20 microg/dl is a threshold for health effects in children exposed acutely to airborne lead). The estimated potential long-term and short-term exposures at the downwind West Dallas community did not result in more than 5% of children exceeding the target blood lead levels. The models were also used to estimate air lead levels for short-term and long-term exposures that would not exceed specified levels of risk (risk-based concentrations, RBCs). RBCs were derived for various daily exposure durations (3 or 8 h/day) and frequencies (1-7 days/week). RBCs based on the ICRP model ranged from 0.3 (7 days/week, 8 h/day) to 4.4 microg/m(3) (1 day/week, 3 h/day) for long-term exposures and were lower than those based on the IEUBK model. For short-term exposures, the RBCs ranged from 3.5 to 29.0 microg/m(3). Recontamination of remediated residential yards from deposition of air lead emitted during remedial activities at the RSR Superfund site was also examined. The predicted increase in soil concentration due to lead deposition at the monitoring station, which represented the community at large, was 3.0 mg/kg. This potential increase in soil lead concentration was insignificant, less than 1% increase, when compared to the clean-up level of 500 mg/kg developed for residential yards at the site.

Factors associated with elevated blood lead concentrations in children in Karachi, Pakistan.

To confirm whether blood lead concentrations in Karachi were as high as reported in 1989 and to identify which types of exposure to lead contribute most to elevated blood lead concentrations in children in Karachi. A total of 430 children aged 36-60 months were selected through a geographically stratified design from the city centre, two suburbs, a rural community and an island situated within the harbour at Karachi. Blood samples were collected from children and a pretested questionnaire was administered to assess the effect of various types of exposure. Cooked food, drinking-water and house dust samples were collected from households. About 80% of children had blood lead concentrations 10 g/dl, with an overall mean of 15.6 g/dl. At the 5% level of significance, houses nearer to the main intersection in the city centre, application of surma to children's eyes, father's exposure to lead at workplace, parents' illiteracy and child's habit of hand- to-mouth activity were among variables associated with elevated lead concentrations in blood. These findings are of public health concern, as most children in Karachi are likely to suffer some degree of intellectual impairment as a result of environmental lead exposure. We believe that there is enough evidence of the continuing problem of lead in petrol to prompt the petroleum industry to take action. The evidence also shows the need for appropriate interventions in reducing the burden due to other factors associated with this toxic element.

Blood lead concentrations in children: new ranges

Background: Lead exposure in young children may have adverse neurodevelopmental effects. Currently, an increased blood lead concentration is defined as ≥10 μg/dl for males and females of all ages, including children younger than 6 years. Using a large hospital population ( n=11,145), we define more specific ranges for pediatric blood lead concentrations. Methods: Pediatric blood lead concentrations were determined (atomic absorption spectrophotometry) on patient samples accrued from January 2001 to June 2002, and the data was analyzed employing the Hoffman approach. Results: For lead, the 2.5th and 97.5th percentiles for subjects aged 0 to 12 months were 2.3 to 4.7 μg/dl for females and 1.8 to 4.9 μg/dl for males. The 97.5th percentiles increased for the 1–2 years age group both for females (5.2 μg/dl) and males (5.6 μg/dl). There was a significant decrease in blood lead concentrations after age 10 years, the 97.5th percentile being 4.4 μg/dl in both female and male subjects. The values in all corresponding age groups were similar for females and for males. The medians of all age groups were similar for females and for male subjects. Conclusion: The blood lead concentrations are much lower compared to previously published data.

Efficacy of d-Penicillamine in Reducing Lead Concentrations in Children: A Prospective, Uncontrolled Study

Objective: To evaluate the efficacy of oral d-penicillamine therapy in children with high blood lead concentrations. Design: A prospective, uncontrolled study. Methods and Patients: Seven children (2–16 y old; mean 8.7) with elevated blood lead concentrations but no symptoms of lead poisoning were treated with oral d-penicillamine. Lead-contaminated homemade flour as found to be the source of poisoning. Mean ± SD blood lead concentrations prior to therapy were 60.3 ± 12.9 μg/dL (range 47.8–83). Mean blood zinc protoporphyrin (ZPP) was 337.86 ± 58.55 μmol/mol hemoglobin (Hb) (range 247–394). Results: Ninety days of treatment with d-penicillamine lowered the mean blood lead concentration by 31.7% to a mean of 40.7 ± 8.6 μg/dL (range 30–53) and lowered mean ZPP blood concentrations by 40% to a mean of 201.14 ± 14 μmol/mol Hb (range 150–278). Three patients with blood lead concentrations &gt;45 μg/mL at the end of this therapy were subsequently treated with succimer, an alternative oral chelator; the blood lead concentrations were further reduced to &lt;45 μg/mL. Conclusions: d-Penicillamine therapy significantly reduced blood lead concentrations but did not achieve acceptable lead and ZPP concentrations for young children. Therefore, we conclude that 90 days of d-penicillamine treatment is of limited effectiveness in young children who have high blood lead concentrations and also show symptoms of lead poisoning.

Elevated Blood Lead Concentrations in Children Living in Isolated Communities of the Kola Peninsula, Russia

ABSTRACT Lead levels were determined in children aged 5–14 in three communities: two groups (N = 24 and 39) from Apatity, an industrial city; a group (N = 47) from Lowozero, an isolated Saami village; and another (N = 14) from Krashnochelie, a remote native village with Sami, Komi, and Nenets populations. As in the northwestern James Bay region of Canada, unexpectedly high blood lead concentrations were found in the most isolated community, namely Krashnochelie. The median lead concentration in Krashnochelie was significantly higher (p &lt; 0.01 or p &lt; 0.02) than those for the other village and city. In the Krashnochelie group, the lead levels were not gender dependent. The percentage of children with blood lead concentrations at or above the medical concern level of 0.48 μmol/l was highest (36%) in Krashnochelie, compared to 8% in Apatity and 6% in Lowozero. All but two of the 124 individuals tested had ferritin concentrations above that indicative of depleted iron stores (10 μg/l for age &lt;14 years); the median ferritin values were comparable for all four communities. Iron status differences can therefore not explain the elevation of blood lead concentrations in the Krashnochelie group. A number of explanations are provided to account for the implied differences in lead exposure in the four study groups.

Sociodemographic and behavioural determinants of blood lead concentrations in children aged 11‐13 years

To describe the determinants of blood lead concentration in children with long term environmental exposure to lead. Prospective cohort study. The lead smelting town of Port Pirie, South Australia, and surrounding townships. 326 children born in and around Port Pirie, 1979-1982, followed up until age 11-13 years in 1993-1994. Blood lead concentrations assessed at birth and at multiple ages up to 11-13 years; average lifetime blood lead concentration. Mean blood lead concentration rose sharply over the ages 6 to 15 months, reached a maximum around 2 years of age, and declined steadily as the children grew older. There was no difference in blood lead concentration between boys and girls until they reached the age of 11-13 years, when mean blood lead concentration in boys (8.4 micrograms/dL [0.41 mumol/L]) was slightly higher than in girls (7.5 micrograms/dL [0.36 mumol/L]). Residential area and father's employment site were the two variables most strongly predictive of a child's blood lead concentration at the end of primary school. Poorer-quality home environment was also found to be an independent contributor to blood lead concentrations. Age-related factors, and possibly recent concerted efforts to decrease entry or re-entrainment of lead into the environment at Port Pirie, have resulted in most children in our study having blood lead concentrations below 10 micrograms/dL (0.48 mumol/L) at the end of their primary school years. Lead exposure during a child's early years remains an important contributor to average lifetime exposure.

Questions de neurotoxicologie au cours du développement : interprétation et implications des données

The potential for environmental contaminants to produce neurological, cognitive, or other behaviour deficits as a result of developmental exposure has received increasing attention. The focus has shifted from description of frank neurotoxicity observed in a relatively few individuals to more subtle impairment in a much greater number of children. With this shift has come the recognition that subtle deficits such as a small decrease in IQ can have important societal impact when large numbers of children are affected. For example, the result of a 1 μg/dL decrease in blood lead concentration in children in the United States with blood lead concentrations between 10 and 20 μg/dL would translate into a savings of 5–7.5 billion U.S. dollars a year in increased earning power alone. In addition, behavioural problems such as increased aggression and poor social adjustment identified early in childhood may escalate to serious antisocial behaviour such as delinquency as the child approaches puberty. Exposure to neurotoxic agents during development or over a significant portion of the lifespan may also result in acceleration of age-related neurodegenerative diseases. Such changes in the functional abilities of a significant proportion of a population have potentially serious consequences for society as well as for affected individuals.

Biological monitoring of lead exposure in high risk groups in Berat, Albania.

STUDY OBJECTIVE: To determine blood lead concentrations in children living in an area with a battery plant in Berat, Albania. Another aim was to determine blood lead concentrations in mothers...

Lead poisoning in children.

Increased lead exposure and increased body burden of lead remains a significant problem for children in the United States. With the increased use of blood level screening methods, a large percentage of children in many industrialized countries are being tested as a being at risk. A controversy continues over the definition of what population to screen and at what age to screen. There are parts of the United States, especially rural areas and health maintenance organization populations, where screening for lead exposure has not been productive. A new drug, DMSA (meso 2,3-dimercaptosuccinic acid) has been approved for oral chelation of children with increased body burden of lead. At the present time it is labeled for use in children with blood lead concentrations in excess of 45 micrograms/dL. Evidence exists that DMSA is effective in lowering the blood lead concentrations in children with levels between 25 and 45 micrograms/dL. The long-term effectiveness of chelation at lower levels is at present uncertain. There remains no substitution for strict environmental decontamination in the home environment of children and the workplace environment of their parents.

Lead in hair and urine of children and adults from industrialized areas.

The study of hair and urine lead concentrations in urban populations of various age groups exposed to contaminating effects of industry and transport and the corresponding analysis of lead in ambient air and soil have made it possible to determine the percentage of subjects showing evidence of elevated lead bioconcentrations. The highest lead concentrations among children were found among those who resided near a copper smelter (18.2 micrograms/g), a lead-cadmium plant (31.1 micrograms/g), and a storage battery factory (48.3 micrograms/g). In adults who resided in the same area, hair lead was lower; however, it exceeded the control group values by up to five times. Hair lead concentration in children correlated with lead content in air and soil (r = 0.7 and r = 0.74, respectively). In the majority of European countries and in the United States, legislative acts have been adopted recently to sharply reduce lead content in gasoline (i.e., from 0.4 to 0.15 g/l). Drastic measures need to be taken to diminish lead concentration in ambient air in Russia. Biomonitoring should be applied in preventive medicine, including medical inspection of industrial workers.

Factors influencing lead concentrations in shed deciduous teeth

Data collected for the Edinburgh Lead Study have been used to investigate lead concentrations in children's naturally shed deciduous teeth. A within-child multiple-regression analysis has shown that the upper jaw has a higher concentration of lead than the lower, and that there is a gradient of decreasing concentration from the front to the back of the mouth. Even after the effects of jaw and tooth type have been allowed for, the concentration is still found to be negatively correlated with the weight of the tooth and with the age at which the tooth was shed. No statistically significant effects could be attributed to caries, fillings, or the incomplete resorption of roots. A single-valued index of tooth lead has been derived for each child, taking into account the fact that children gave different types of teeth.

Child Lead Exposure Determined from Measurement of X-Ray Fluorescence of Teeth in Situ

X-ray fluorescence from lead when irradiated by gamma rays from a Co-57 source was utilized to measure the lead concentration in children's teeth in situ. The sensitivity of the method was adequate to detect 15 PPM from a gamma ray exposure to the tooth approximately 1/10 the exposure of a routine dental x-ray examination. The tooth lead levels assayed using x-ray fluorescence correlated well with chemical assay techniques for both extracted permanent and shed primary teeth. Thirty children from the Children's Hospital of Philadelphia suspected of having elevated lead levels had tooth lead levels measured in situ determined using the x-ray fluorescent technique. The tooth lead concentration varied from a low of 16 PPM to a high of 56 PPM.