Blood Lead Levels

Lead exposure is a common public health problem. Exposure to the metal can cause hematological, gastrointestinal, rheumatological, endocrine, neurological and renal problems in humans. However, effects on the thyroid gland are controversial. We retrospectively investigated thyroid function parameters in 65 adult males who had been occupationally exposed to lead. We then compared the findings with those of 60 male patients who had no history of lead exposure or thyroid abnormalities, who served as the control group. The mean ages of the lead-exposed workers and the controls were 34.3 ± 7.9 and 32.9 ± 6.6 years respectively. Blood lead levels in the lead-exposed workers were significantly higher than in the control group. The lead-exposed workers were assigned to one of three groups according to their blood lead levels, as follows: 40–59 μg/dl, 60–79 μg/dl, or 80 μg/dl and above. Thyroid Stimulating Hormone (TSH) levels in the 80 μg/dl and above group were significantly higher than in...

Background: Artisanal mining activities have become a significant occupation among the inhabitants of Enyigba community in Ebonyi State, Nigeria. Objective: This study investigated the blood-lead levels of some subjects of Enyigba lead-zinc mining community. Methods: A questionnaire on health hazards and safety measures associated with the mining activities was administered to the participants. Blood samples were collected for the analysis of blood-lead levels by standard methods. Results: Males dominated in the occupationally-exposed (56.18%) and females (62.30%) dominated in the environmentally-exposed. Almost all the occupationally-exposed subjects (96.63%) and environmentally-exposed subjects (80.33%) store mined products in their houses. Majority of the occupationally-exposed subjects (69.67%) were not aware of the hazards and safety measures, and 75.28% did not use personal protective devices. Headache (74.40%) was reported as the most prevalent sickness. The occupationally and environmentally-exposed subjects had mean bloodlead levels of 42.30µg/dl and 28.67µg/dl, respectively, which were significantly higher (p<0.0001) than the control levels. Conclusion: Given the increasing participation of many households in lead mining activities and the storage of the lead products in homes, lead contamination may remain a significant public health issue in the study area.

Objectives.To assess the prevalence of elevated blood lead levels (EBLLs) among children before and after foster care placement, and to compare the prevalence of EBLLs among children in foster care with that of their siblings and the general population.Methods.We conducted a retrospective cohort study using administrative databases from the Philadelphia Department of Human Services and the Birth Certificate Registry and the Childhood Lead Poisoning Prevention Program at the Philadelphia Department of Public Health. Logistic regression analyses were performed to control for confounding variables, including age, race, gender, and the year, seasonal timing, and source (capillary vs venous) of test.Results.From June 1992 to May 1997, there were 1824 children in foster care with available blood lead results in the Childhood Lead Poisoning Prevention Program database. Of these, 519 (28%) had initial lead screening before foster care placement and 654 (36%) after placement. There were 821 ...

Children are the most susceptible population to lead exposure because of three interacting factors; they have more opportunity for contact with lead sources due to their activities, lead absorption occurs more readily in a child compared to an adult, and the child's development is more vulnerable to lead than adults. Low levels of lead in the blood have been shown to cause adverse health effects; the level of concern for children is currently 10 g / dl. The contribution of dietary exposure of lead to increased blood lead levels ( PbB ) is not well characterized. This study was conducted to measure potential dietary lead intakes of children 2 to 3 years of age who live in homes contaminated with environmental lead. Objectives were to estimate lead intakes for children consuming food in contaminated environments, recognizing unstructured eating patterns and to investigate if correlations exist between daily dietary exposure and measured PbB. Dietary exposure was evaluated by collecting samples that were typical of the foods the young children ate in their homes. A 24 -h duplicate of all foods plus sentinel foods, i.e., individual items used to represent foods contaminated during handling, were collected from 48 children. Ten homes were revisited to obtain information on the variation in daily dietary intakes. Drinking water was evaluated both as part of the segregated beverage sample composite and by itself. Additional information collected included lead concentrations from hand wipes, floor wipes, and venous blood, and questionnaire responses from the caregiver on activities potentially related to exposure. Activities and hygiene practices of the children and contamination of foods in their environment influences total dietary intake. Estimated mean dietary intakes of lead ( 29.2 g Pb / day ) were more than three times the measured 24 -h duplicate -diet levels ( 8.37 g Pb/ day ) , which were almost six times higher than current national estimates ( 1.40 g Pb / day ) . Statistically significant correlations were observed between floor wipes and foods contacting contaminated surfaces, hand wipes and foods contacting contaminated hands and surfaces, and hand wipes and floor wipes. This study indicates that the dietary pathway of exposure to lead is impacted by eating activities of children living in lead -contaminated environments and that analysis of foods themselves is not enough to determine excess dietary exposures that are occurring. Journal of Exposure Analysis and Environmental Epidemiology ( 2000 ) 10, 723 ± 731.

Lead toxicity is a major global health concern, affecting both children and adults through environmental, occupational, and consumer product exposure. Despite regulatory efforts to minimize risk, lead continues to pose significant hazards, particularly in developing regions and among vulnerable populations. One of the classical, though now rare, clinical signs of chronic lead poisoning is the Burtonian line-a bluish-black pigmentation along the gingival margin caused by the reaction between circulating lead and hydrogen sulfide produced by oral bacteria. This review explores the historical background, sources of exposure, pathophysiological mechanisms, and systemic manifestations of lead toxicity. It emphasizes the diagnostic significance of Burtonian lines in identifying chronic lead exposure. The article also discusses current diagnostic approaches including blood lead level testing, hematological findings, and radiographic imaging. Treatment strategies focus on exposure elimination, chelation therapy, and supportive care. While Burtonian lines are infrequently observed today due to improved public health measures, they remain an important clinical clue in diagnosing lead poisoning, especially in individuals with poor oral hygiene. Early recognition and intervention are vital to preventing the irreversible effects of lead on multiple organ systems.

Leaded gasoline and lead paints are still in use in the Democratic Republic of Congo but data on blood lead levels in the general population are not available. We evaluated the Pb impregnation in children and adults (0 -70 years old) in Kinshasa. Geometric mean blood lead was 120 µg/L (95% CI: 115 -125), with a higher concentration in men than in women (127 vs 114 µg/L, p=0.01). Sixty-three percent of children aged less than 6 years old presented blood lead levels above the 100 µg threshold. In the adult population, occupations with a potential risk of exposure to gasoline (car mechanics or garage owners, taxi drivers, conveyors and gas pump attendants) were associated with an extra blood lead of about 65µg/L. This study indicates a relatively important Pb impregnation of the Kinshasa population. It demonstrates the existence of a major public health issue requiring corrective actions and the implementation of an appropriate regulation.

Background. The clinical significance of blood lead levels (BLLs) in chronic peritoneal dialysis (CPD) patients was undetermined prior to this study. Methods. A total of 315 patients on CPD were included in this 18-month prospective study. BLLs measured at baseline were categorized according to a BLL tertile of high (>8.66 μg/dL), middle (5.62-8.66 μg/dL) and low (<5.62 μg/dL) for cross-sectional analyses. Mortality and cause of death were recorded for longitudinal analyses. Results. At baseline, patients with high BLLs had a trend of higher parathyroid hormone and lower residual renal function than patients in other groups. Stepwise multiple regression analysis found that parathyroid hormone positively correlated and residual renal function negatively correlated with logarithmic-transformed BLLs in CPD patients after other confounders were adjusted. At the end of follow-up, 37 (11.7%) patients had died. Kaplan-Meier analysis showed that patients with high BLLs had greater mortality than those with middle and low BLLs (P = 0.008). Cox multivariate analysis showed that, using the low BLL group as the reference, basal high BLLs (hazard ratio [HR] = 3.745, 95% confidence interval [95% CI] = 1.218-11.494, P = 0.001) and middle BLLs (HR = 1.867, 95% CI = 1.618-2.567, P = 0.001) were associated with increased HR for all-cause mortality for CPD patients. There is a significant trend (P < 0.001) of HR for mortality trend tests among the three study groups. Conclusions. BLLs are associated with residual renal function and hyperparathyroidism and are related to increased HR for all-cause 18-month mortality in CPD patients.

Background Lead stabilizers (e.g., lead sulfate, lead stearate) are common additives in plastics used in electrical devices. In 1997, three plastics compounders at one California company were severely lead-poisoned. Methods The poisonings were investigated by interviewing the workers, employer, and treating physician and reviewing medical records and environmental monitoring results. In addition to measuring blood lead levels (BLLs), noninvasive K X-ray fluorescence was used to measure bone lead concentration of the index case. Results Blood lead concentrations of the three workers at time of diagnosis were 159, 114, and 108 mg/dl. The worker with highest exposure presented with clinical findings of crampy abdominal pain, constipation, normocytic anemia, fatigue, and reversible azotemia. Bone lead concentration in his tibia, calcaneous, and patella were 102, 219, and 182 ppm, respectively. The poisonings resulted from uncontrolled use of powdered lead sulfate stabilizer. Clinicians should be aware of potential serious overexposure to lead in compounding of plastics.

Background-Attention-deficit/hyperactivity disorder (ADHD) and low-level lead exposure are high-prevalence conditions among children, and studies of large populations have suggested that these conditions are related. We examine this relationship in children from a community sample exposed to average background levels of lead who have a diagnosis of ADHD that is established by clinical criteria. Methods-One hundred fifty children ages 8-17 years participated (mean age = 14 years; 53 control subjects, 47 ADHD Predominantly Inattentive type, 50 ADHD-Combined type). Diagnosis was formally established with a semi-structured clinical interview and parent and teacher ratings. Children completed intelligence quotient (IQ) measures and the stop task (a neuropsychological measure). Lead was assayed from whole blood with inductively coupled plasma mass spectrometry. Results-Blood lead levels in this sample closely matched US population exposure averages, with a maximum level of 3.4 μg/dL. Blood lead levels were statistically significantly higher in ADHDcombined type than in non-ADHD control (p < .05) children. Blood lead was associated with symptoms of hyperactivity-impulsivity but not inattention-disorganization, after control of covariates. Blood lead levels were linked with a lower IQ (p < .05), but IQ did not account for effects on hyperactivity. Instead, hyperactivity mediated effects of lead on IQ. Effects of blood lead on hyperactivity-impulsivity were mediated by poor performance on the stop task. This mediation effect was independent of effects of lead on IQ. Conclusions-Low-level lead exposure might be an important contributor to ADHD. Its effects seem to be mediated by less effective cognitive control, consistent with a route of influence via striatal-frontal neural circuits.

Objetivo: Determinar la asociación entre intoxicación plúmbica crónica y alteraciones del crecimiento y desarrollo cognitivo-emocional en niños del colegio “María Reiche”- Callao. Diseño: Estudio observacional de corte transversal. Material y métodos: A 70 niños de 8 a 12 años de edad del C.E. Nº 5045 “María Reiche” del A.A.H.H. “Puerto Nuevo”- Callao, que participaron en el estudio de dosaje de plomo en sangre hecho por la Dirección General de Salud Ambiental en 1999, se les aplicó pruebas de seguimiento de instrucciones, habilidades motoras, comunicativas, manipulativas, académicas y la lista de chequeo de ansiedad. Se midió el coeficiente intelectual e índice de masa corporal. Para el procesamiento de los datos se empleó las pruebas chi-cuadrado, t de Student, correlación y regresión lineal simple, usando el paquete estadístico SPSS versión 11.0, con un nivel de confianza de 95%. Resultados: Los niveles de plomo en sangre y los grados de ansiedad se relacionaron significativament...

Objective. Blood lead level BLL and growth parameters including weight and height, in children, living in lead mining area was surveyed. Methods. Two groups of 7-11 yr old children, including 45 from a lead mining area (Angooran-Zanjan Province-Iran) and 36 from control area (similar area to the study area, but not lead mining: Ijrood-the same province), were selected to assess BLL (by atomic absorption spectrometry) and growth parameters. In the children of the study and control areas, mean BLLs were 36.97±24.67 (µg/dL; mean ± SD) and 15.57 ± 13.35 (µg/dL; mean±SD), respectively (P=0.0005). No significant correlation was found between BLL in children and their fathers' occupation. In addition, there was no significant difference in growth parameters, including weight and height, in the children of two groups. Regarding the results of this study, environmental exposure due to living in lead mining area can lead to increased BLL in children. In addition, our results suggest there is no significant effect of BLL on growth parameters in children in lead mining area. Since some clinical and sub clinical problems are strongly probable when BLL is increased, special attention of the relevant organizations, and more research about the problem and its outcome, is recommended.

Tactile defensiveness in children is associated with difficult social relations, emotional dysregulation, and inattention. However, there are no studies of lead exposure and tactile defensiveness in children or animals in spite of the fact that lead exposure is also associated with inattention and emotional dysregulation. OBJECTIVES: In this study we tested whether lead exposure induces tactile defensiveness in rhesus monkeys. METHODS: We tested 61 monkeys from a 3 (no lead, 1-year lead, 2-year lead) × 2 (succimer chelation or not) factorial experiment for tactile defensiveness at 4 years of age. Lead-treated monkeys had been orally administered lead in a daily milk solution from 8 days of life to either 1 or 2 years of age to produce blood lead levels of 35-40 mg/dL. Succimer chelation therapy or placebo was administered at 1 year of age. We measured tactile defensiveness using six repeated trials of each of three textures as a swipe to the cheek and neck. RESULTS: Lead-exposed monkeys showed higher negative responses to repeated tactile stimulation compared with controls. Blood lead during the first 3 months of life was positively correlated with the negative response on the tactile defensiveness test. There was an interaction of lead exposure × succimer chelation × trials, but it is not clear that succimer chelation was beneficial with respect to tactile defensiveness. CONCLUSIONS: This is the first report to implicate lead as a potential cause of tactile defensiveness. Research should examine whether lead exposure is associated with tactile defensiveness in children.

Tactile defensiveness in children is associated with difficult social relations, emotional dysregulation, and inattention. However, there are no studies of lead exposure and tactile defensiveness in children or animals in spite of the fact that lead exposure is also associated with inattention and emotional dysregulation. OBJECTIVES: In this study we tested whether lead exposure induces tactile defensiveness in rhesus monkeys. METHODS: We tested 61 monkeys from a 3 (no lead, 1-year lead, 2-year lead) × 2 (succimer chelation or not) factorial experiment for tactile defensiveness at 4 years of age. Lead-treated monkeys had been orally administered lead in a daily milk solution from 8 days of life to either 1 or 2 years of age to produce blood lead levels of 35-40 mg/dL. Succimer chelation therapy or placebo was administered at 1 year of age. We measured tactile defensiveness using six repeated trials of each of three textures as a swipe to the cheek and neck. RESULTS: Lead-exposed monkeys showed higher negative responses to repeated tactile stimulation compared with controls. Blood lead during the first 3 months of life was positively correlated with the negative response on the tactile defensiveness test. There was an interaction of lead exposure × succimer chelation × trials, but it is not clear that succimer chelation was beneficial with respect to tactile defensiveness. CONCLUSIONS: This is the first report to implicate lead as a potential cause of tactile defensiveness. Research should examine whether lead exposure is associated with tactile defensiveness in children.

This study evaluates the relationship of children's hygiene habits and food -handling behaviors on lead levels on hands and handled foods for toddlers living in lead -contaminated homes. Forty -eight inner city toddlers previously identified as having elevated blood lead levels participated in three consecutive days of designated food -handling activities. During the visits, duplicate diets were obtained, the child handled a banana, a hot dog, and had his / her hands wiped with a moist towelette. In addition, wipe samples were collected from the kitchen floor, and food items were deposited on and subsequently collected from the kitchen floor. All samples were analyzed for lead. The child's caregiver completed a questionnaire, which addressed the child's hygiene and eating behaviors. It was demonstrated that children's contact with residential dust containing lead can transfer lead to food. Both lead in the home and on the children's hands contribute to the contamination of food, and hence potential dietary exposure. Mean lead in handled bananas was 26 g / kg and on hot dogs 65 g / kg, and mean lead values on cheese and apple slices that had been on the floor were 119 and 215 g / kg. In addition, the child's hygiene habits as reported by the parent indicate that lack of basic hygiene patterns within a high lead environment can contribute to children's dietary exposure to lead.

Implication of particulate participation of exhaust fumes in exacerbating cellular damage has been researched. The purpose of this research is to determine the particulate inhalation of exhaust fume, specifically, Lead with some biomarkers of oxidative stress, among different ages of commercial tricyclists. This was investigated in 120 apparently healthy non smokers' commercial tricyclists and non-drivers in Kano Metropolis, achieved by determining serum Lead level, Plasma Malondialdehyde level, Catalase activity, Vitamin C and Vitamin E levels in the subjects. The subjects were divided into two groups; commercial tricyclists (N = 70-Test) and control group (N = 50-non-drivers). The level of Plasma malondialdehyde was significantly higher (p<0.05) in test group (12.92±4.89 µM) compared with control group (5.88±4.91 µM). Similarly, the level of serum vitamin E is significantly higher (p<0.05) in test group (32.05±10.66 µg/L) compared with control group (21.42±8.55 µg/L). Serum vitamin C test group (2.02±0.99 mg/dL) shows a significance increase (p<0.05) over control group (1.35±0.84 mg/dL). The blood lead level of test group is significantly higher (p<0.05) (16.36±8.53 µg/dL) compared with control group (9.44±4.86 µg/dL). There was no statistical significant difference between the test group compared to control group in catalase. Higher plasma malondialdehyde in test group was suggestive of higher oxidative stress in the subjects. As a result of the raised blood lead levels, MDA levels tends to be raised with increase in age, and accumulative in adults than in children as age progresses. Thus, the significance of this study reveals cautiousness to occupational and accidental exposures to exhaust fumes.

Lead pollution is a substantial problem in developing countries such as India. The US Centers for Disease Control and Prevention has defined an elevated blood lead level in children as 10 lg/dl, on the basis of neurologic toxicity. The US Environmental Protection Agency suggests a threshold lead level of 20-40 lg/dl for risk of childhood anemia, but there is little information relating lead levels <40 lg/dl to anemia. Therefore, the authors examined the association between lead levels as low as 10 lg/dl and anemia in Indian children under 3 years of age. Anemia was divided into categories of mild (hemoglobin level 10-10.9 g/dl), moderate (hemoglobin level 8-9.9 g/dl), and severe (hemoglobin level <8 g/dl). Lead levels <10 lg/dl were detected in 568 children (53%), whereas 413 (38%) had lead levels 10-19.9 lg/dl and 97 (9%) had levels 20 lg/dl. After adjustment for child's age, duration of breastfeeding, standard of living, parent's education, father's occupation, maternal anemia, and number of children in the immediate family, children with lead levels 10 lg/dl were 1.3 (95% confidence interval: 1.0, 1.7) times as likely to have moderate anemia as children with lead levels <10 lg/dl. Similarly, the odds ratio for severe anemia was 1.7 (95% confidence interval: 1.1, 2.6). Health agencies in India should note the association of elevated blood lead levels with anemia and make further efforts to curb lead pollution and childhood anemia.

We compared high-precision lead isotopic ratios in deciduous teeth and environmental samples to evaluate sources of lead in 10 children from six houses in a primary zinc-lead smelter community at North Lake Macquarie, New South Wales, Australia. Teeth were sectioned to allow identification of lead exposure in utero and in early childhood. Blood lead levels in the children ranged from 10 to 42 µg/dL and remained elevated for a number of years. For most children, only a small contribution to tooth lead can be attributed to gasoline and paint sources. In one child with a blood lead concentration of 19.7 µg/dL, paint could account for about 45% of lead in her blood. Comparison of isotopic ratios of tooth lead levels with those from vacuum cleaner dust, dust-fall accumulation, surface wipes, ceiling (attic) dust, and an estimation of the smelter emissions indicates that from approximately 55 to 100% of lead could be derived from the smelter. For a blood sample from another child, > 90% of lead could be derived from the smelter. We found varying amounts of in utero-derived lead in the teeth. Despite the contaminated environment and high blood lead concentrations in the children, the levels of lead in the teeth are surprisingly low compared with those measured in children from other lead mining and smelting communities.

This paper documents the first precise lead isotope measurements for men, women and children from the same family in an attempt to determine the source of lead in their blood. The subjects reside in one of the world's largest lead mining cities, Broken Hill, NSW, Australia. Biological and environmental samples have been compared using isotopic compositions and lead contents. Adult males have isotopic profiles (or compositions) which appear to be related to their occupations. Adult females have low blood leads (<10 ~g dL 1) and their main source of lead is not from the mine dumps around which the city is built but probably from a mixture of petrol, food and perhaps water.The blood lead contents in children from 1 to 14 years old vary and are partly dependent on age. There is a moderate correlation of blood lead and isotopic compositions (r = 0.73) indicating that a significant component of blood lead derives from the mine dumps in children with elevated blood leads. Some children with blood leads <20 ~g dL 1, however, also have a dominant component of mine lead in their blood

Preventive approaches to childhood lead poisoning are critical for addressing this longstanding environmental health concern. Moreover, increasing evidence of cognitive effects of blood lead levels < 10 µg/dL highlights the need for improved exposure prevention interventions. OBJECTIVES: Geographic information system-based childhood lead exposure risk models, especially if executed at highly resolved spatial scales, can help identify children most at risk of lead exposure, as well as prioritize and direct housing and health-protective intervention programs. However, developing highly resolved spatial data requires labor-and time-intensive geocoding and analytical processes. In this study we evaluated the benefit of increased effort spent geocoding in terms of improved performance of lead exposure risk models. METHODS: We constructed three childhood lead exposure risk models based on established methods but using different levels of geocoded data from blood lead surveillance, county tax assessors, and the 2000 U.S. Census for 18 counties in North Carolina. We used the results to predict lead exposure risk levels mapped at the individual tax parcel unit. The models performed well enough to identify high-risk areas for targeted intervention, even with a relatively low level of effort on geocoding. CONCLUSIONS: This study demonstrates the feasibility of widespread replication of highly spatially resolved childhood lead exposure risk models. The models guide resource-constrained local health and housing departments and community-based organizations on how best to expend their efforts in preventing and mitigating lead exposure risk in their communities.

In March, 1997, a municipal health officer in a small island south of Manila requested for the conduct of a health assessment of the community because of the incidence of hematological related illnesses/mortality among residents of along the coastal area of a mining community. 85 deaths were recorded from 1975-1996. Leukemia was diagnosed in 62 (72. 94%) patients, 16 (18. 82%) were aplastic anemia, 4 (4. 71%) were blood dyscrasia and 3 (3. 53%) otherbloodrelatedailments. Health and environmental assessment activities were conducted by a composite team from the DOH and the llP-National Poisons Control and Information Service Health examinations included a review of systems, complete medical history, physical and neurologie evaluations and biologie examinations. Initial health examination showed 7 schoolchildren out of 108 volunteer subjects from 6 barangays have elevated blood lead levels exceeding the WHO recommended limits of 10 ugidl. Mean blood lead levels = 15. 86 ug/dl (Range : 13-19 ug/dl). Electromyograph and nerve conduction velocity (EMG-NCV) results were compatible with peripheral axonal degeneration in 6 children and beginning damage in 1 child. Detoxification therapy was done for a 19 day course using dimercaptosuccinic acid (DMSA). In the succeeding health assessment, 59/59 schoolchildren from 3 barangays namely were found to have elevated blood lead levels. Range : 10-18 ug/dl. 43/64 (67. 18%) have anemia. Soil samples collected 7 km from the causeway and the causeway itself showed three (3) sites with lead. cadmium, copper and zinc levels were found in all sampling sites. Ambient air monitoring results showed lead values exceeding the recommended US-EPA limits.

This study aimed to clarify the role of blood lead level (Pb-B) as one of the cardiovascular risk factors. To evaluate the cardiovascular risk the second derivative finger photoplethysmogram (SDPTG) was used. The subjects comprised of 420 male bus drivers in Thailand. The subjects' age ranged from 20 to 60 yr. Mean age (± standard deviation) were 41.6 (± 7.7) yr. Mean working years was 8.8 (± 6.8) yr. Pb-B ranged from 2.5 to 16.2 µg/dl with the mean Pb-B of 6.3 (± 2.2) µg/dl. The mean of aging index of SDPTG (SDPTG-AI) were -0.50 (± 0.30). The SDPTG-AI increases with age, Pb-B, smoking and alcohol consumption. There was significant correlation between Pb-B and SDPTG-AI after controlling for age, body mass index and lifestyle factors. These results suggest that Pb-B is possibly an independent cardiovascular risk factor for bus drivers exposed to lower level of lead.

Blood lead concentration is still most commonly used to assess the degree of exposure to environmental lead. However, blood lead levels are relatively transient and so tissues such as hair which store lead over longer periods need to be explored as bioindicators of lead toxicity. The results of such an investigation into hair are presented. These results indicate that there

On a community basis, urban soil contains a potentially large reservoir of accumulated lead. This study was undertaken to explore the temporal relationship between pediatric blood lead (BPb), weather, soil moisture, and dust in Indianapolis,

Previous reports have shown that blood lead levels in humans are associated with a polymorphic form of (5-aminolevulinate dehydratase (ALAD), an enzyme of heme biosynthesis that binds and is inhibited by lead. We hypothesized that ALAD levels may influence the distribution and accumulation of lead in the blood and target organs. To assess this, we studied strains of mice that differ in the numbers of copies of the ALAD gene. Our findings showed that mice with a duplication of the ALAD gene (DBA) accumulated twice the amount of lead in their blood and had higher lead levels in kidney and liver than mice with a single copy of the gene (C57) exposed to the same oral doses of lead during adulthood. Hybrid animals showed intermediate blood lead levels. Levels of blood zinc protoporphyrin (ZPP) increased with lead exposure in C57 animals while they were not affected in DBA mice, suggesting protection from production of this abnormal enzyme in mice with a duplication of the gene. Except for these protective effects in the formation of ZPP in DBA animals, duplication of the ALAD gene was found to increase lead accumulation. We conclude that although these mouse strains do not precisely replicate the polymorphism observed in humans, they may be used as a model to study genetic influences in lead bioaccumulation. Understanding genetic factors that affect susceptibility to lead-induced intoxication could have important implications for public health and intervention initiatives. These mouse strains may represent a useful model for future study of the role of ALAD in lead intoxication.

Objective: To determine whether a polymorphism the in d-aminolevulinic acid dehydratase (ALAD) gene modifies the neurotoxicity of lead in older adults. Methods: The authors studied men participating in the Department of Veterans Affairs' Normative Aging Study, assessing their recent exposure to lead by measuring blood lead (n = 915) at each triennial clinic visit, and, beginning in 1991, assessing their cumulative exposure by measuring lead levels in tibia (n = 722) and patella (n = 720), using K-shell x ray fluorescence. Starting in 1993 and again at each triennial visit, the authors administered the Mini-Mental State Examination (MMSE) to assess their cognitive functioning. The relation of the lead biomarkers to MMSE score was evaluated and this association was compared among men who carried the variant allele, ALAD-2, versus men without the allele. Results: Sixteen per cent of men carried the ALAD-2 allele. Median tibia and patella lead levels (first-third quartile) were 19 (13-28) and 27 (18-39) mg/g. Blood lead levels were consistent with non-occupational exposure: only 6% of men had levels >10 mg/dl. In multivariable adjusted analyses, higher levels of blood lead were associated with poorer performance on the MMSE. This association was most pronounced among ALAD-2 carriers, among whom a 3 mg/dl increment in blood lead (the interquartile range) was associated with a 0.26 point lower mean MMSE score (95% CI 20.54 to 0.01), compared with a 0.04 point lower score (95% CI 20.16 to 0.07) among non-carriers. The modest 0.22 point difference in these associations did not attain statistical significance, however (p interaction = 0.13). The associations between bone lead levels and MMSE score did not vary by ALAD-2 status. Conclusions: Although not statistically significant, these findings suggest that ALAD genotype may modify blood lead's adverse association with cognition among older men who had community exposures to lead. However, despite a relatively large sample size and the use of sensitive methods for measuring lead burden, the evidence overall was fairly weak.

Because body iron burden is inversely associated with lead absorption, genes associated with hemochromatosis may modify body lead burden. Our objective was to determine whether the C282Y and/or H63D hemochromatosis gene (HFE) is associated with body lead burden. Patella and tibia lead levels were measured by K X-ray fluorescence in subjects from the Normative Aging Study. DNA samples were genotyped for C282Y and H63D using polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). A series of multivariate linear regression models were constructed with bone or blood lead as dependent variables; age, smoking, and education as independent variables; and C282Y or H63D as independent risk factors and/or effect modifiers. Of 730 subjects, 94 (13%) carried the C282Y variant and 183 (25%) carried the H63D variant. In the crude analysis, mean tibia, patella, and blood lead levels were consistently lower in carriers of either HFE variant compared with levels in subjects with wild-type genotypes. In multivariate analyses that adjusted for age, smoking, and education, having an HFE variant allele was an independent predictor of significantly lower patella lead levels (p < 0.05). These data suggest that HFE variants have altered kinetics of lead accumulation after exposure. Among elderly men, subjects with HFE variants had lower patella lead levels. These effects may be mediated by alterations in lead toxicokinetics via iron metabolic pathways regulated by the HFE gene product and body iron stores.

This paper presents a case-control study of micronuclei score evaluation as cytogenetic test in male workers exposed to inorganic lead from a non-ferrous metallurgical plant, Romania. Literature data on genotoxic effects of this heavy metal are still matter of discussions. We have compared micronuclei frequency measured from the lymphocytes of both inorganic lead-exposed and radiation-exposed workers as well as their respective matched controls. The study consisted of 60 subjects divided into three groups: lead exposed workers, workers exposed to ionizing radiation and controls. Exposure to inorganic lead was assessed either by determination of lead concentration in the workplace air or by biotoxicological analyses (blood lead level, urine lead level, urine δ-aminolevulinic acid). The results of our investigation showed an increased micronuclei mean score in lead-exposed workers compared to control group (6.0±2.328‰ vs. 2.7±0.978‰, p<0.001). We found that lead produces chromosomal damage comparable to that induced by ionizing radiation (micronuclei mean score 5.55±1.877‰ in subjects exposed to X rays). In conclusion, we propose the use of the micronucleus assay as a screening test for occupationally lead-exposed workers displaying repeated occupational poisoning and pathological outcome.

Controlling residential lead hazards is critical for case management of lead poisoned children. To attain this goal, permanent relocation of the family is sometimes necessary or advisable for many reasons, including poor housing conditions; extensive lead hazards; lack of abatement resources, landlord compliance and local enforcement capacity; and family eviction. During 1996-1998, the Kennedy Krieger Institute implemented a unique capitated Program for case management of Baltimore City children with blood lead concentrations (PbB) 919 2g/dL. The Program provided financial, housing, and social work assistance to facilitate relocation as a means of providing safer housing. Nearly half of the Program families relocated with direct assistance, and 28% relocated on their own. The Program evaluation examined the costs and benefits of relocation. Average relocation cost per child was relatively inexpensive (G$1,500). Average relocation time of 5 months (range G2 months to 912 months) was less than the 8-month average time to complete lead hazard control work in 14 city and state programs funded by U.S. HUD. Relocation was associated with (1) a statistically significant decrease in dust lead loadings on floors, windowsills and window troughs that persisted for one year, and (2) statistically significantly greater decreases in children_s PbB compared to children who did not relocate from untreated homes. Children relocated to housing that met current Federal residential dust lead standards had statistically significant decreases in blood lead levels. Visual inspection did not consistently identify relocation houses with dust lead levels below current Federal standards, indicating that dust testing should be an essential component of future programs. This will require additional resources for dust testing and possibly cleaning and repairs but is expected to yield additional benefits for children. The findings support recent U.S. CDC case management recommendations suggesting that permanent relocation to safer housing is a viable means to reduce children_s lead exposure. The benefits of relocation notwithstanding, 40% of families moved at least twice. Research is needed to better understand how to expedite relocation and encourage families to remain in safe housing. Relocation does not negate owners_ and health authorities' responsibilities to address lead hazards in the child's original house in order to protect future occupants.

Lead has been used in batteries, paints, cosmetics, and medicine throughout history. Environmental exposures of lead are in soil, drinking water, air, dust, and even food. Lead poisoning can be dangerous to human health and cause anemia, kidney dysfunction, hypertension, ischemic disease, degradation of intellectual development, logopathy, abdominal pain, etc. This pilot study aimed to analyze lead poisoning knowledge and potential risks in Batumi, Georgian Autonomous Republic of Adjara. A street-based study was carried out among 196 adult respondents using a questionnaire to analyze socio-demographic data, sources of lead poisoning information, knowledge of lead impact on human health, and potential exposure risks. Results showed that social networks were the major information source for younger adults, while for older respondents, they were primarily accessed through television. Knowledge of lead poisoning's impact on human health was low among younger respondents. Most of the participants had jobs or hobbies involving lead exposure, which can be harmful to their health. The research results indicate the necessity of implementing educational campaigns among young people through social networks and among the elderly through television. The study highlights the need to conduct broader research on lead poisoning knowledge and risks across Georgia's different regions and age groups.

Divided into three subsections: (1.1) Epidemiologic and statistical methods; (1.2) Epidemiologic/observational study reports; and (1.3) Clinical study reports 1.1 Epidemiologic and statistical methods M28. Strömberg U. Empirical Bayes and semi-Bayes adjustments for a vast number of estimations.

This study examined whether lead-induced alterations in selected parameters that are indicative of oxidative stress accompany the toxic effects of lead in red blood cells (RBCs) in vivo. It also explored the possibility that treatment with N-acetylcysteine (NAC) or succimer (meso-2,3-dimercaptosuccinic acid) was capable of reversing parameters indicative of lead-induced oxidative stress. Fisher 344 rats were given 2000 ppm lead acetate in their drinking water for 5 weeks. The lead was then removed and the animals were given NAC (800 mg/kg/day) or succimer (90 mg/kg/day) in their drinking water for 1 week, after which the RBCs were harvested. Animals not given lead and those given lead, but not NAC or succimer, served as negative and positive controls, respectively. At the end of the experiment, blood-lead levels were 35 94 vg/dl in lead-treated animals, which were reduced to 2.5 9 1 vg/dl by treatment with succimer and to 25 93 vg/dl by treatment with NAC. Lead-exposed animals demonstrated signs of anemia as evidenced by anisocytosis, poikilocytosis, and alterations in hemoglobin, hematocrit, and mean corpuscular volume. Lipid peroxidation, as evidenced by increased malondialdehyde (MDA) content, as well as decreases in reduced glutathione (GSH) and increases in catalase and glucose 6-phosphate dehydrogenase (G6PD) activity were noted in RBCs from lead-treated rats, suggesting that the lead induced oxidative stress. In addition, a significant reduction in blood l-aminolevulinic acid dehydratase (ALAD) activity suggested that accumulation and autooxidation of l-aminolevulinic acid might contribute to lead-induced oxidative stress. Treatment with either NAC or succimer reversed lead-induced alterations in MDA and GSH content, but only succimer appeared to partially restore ALAD activity. These results provide in vivo evidence supporting the hypothesis that lead induces oxidative stress in RBCs, which is reversible by treatment with a thiol antioxidant (NAC), as well as a chelating agent (succimer).

Objective: The purpose of this investigation is to analyze childhood blood lead levels and growth status (ages 2Á12) in Dallas, Texas lead smelter communities in the 1980s and 2002, where smelters operated from 1936 to 1990. Methods and materials: A sample of convenience study design was used in two cohorts (n 0360): 1980Á1989 (n 0191) and 2002 (n 0169). Multivariate analysis of variance and covariance and tandem multiple regressions were used to evaluate the association between stature and blood lead level in two time periods. Results: In 2002 average child blood lead level (1.6 mg/dL90.2 SE) was significantly (p B0.001) lower compared to the 1980 cohort mean level (23.6 mg/dL91.3 SE). Average height and weight in 2002 were 4.5 cm and 4.0 kg greater, respectively, than in 1980. Lowered blood lead level was associated with 3.9 cm, 3.5 kg and 1.1 units greater height, weight and body mass index (BMI), respectively. Cohort effect was associated with greater height (0.6 cm), weight (0.5 kg) and BMI (0.1). Conclusion: This investigation reports on child growth in a community before and after the transition from high to low blood lead levels over several decades. Using child growth as a proxy, health status of Dallas's lead smelter communities increased markedly over the past two decades, primarily because of lower blood lead levels, while the poverty rate was only marginally lower.

The area of Copsa Mica (Sibiu County, Romania) is well known because of its high lead concentration in the environment. A large portion of young children have been found to develop lead poisoning. We studied children ages 4-6 years. The blood lead levels were 43.89 µg/dL ± 13.61 µg/dL with an average value of 44.32 µg/dL ± 13.71 µg/dL in boys and 42.98 µg/dL ± 13.78 µg/dL in girls. Blood lead levels were measured using the Lead Care System. The lead concentration on children's hands was measured using KXRay Fluorescence (dust wipes). No correlation was found between blood lead levels and lead concentrations on children's hands. Blood lead levels were correlated with certain behaviors such as the time a child spends playing outdoors.

Controlling residential lead hazards is critical for case management of lead poisoned children. To attain this goal, permanent relocation of the family is sometimes necessary or advisable for many reasons, including poor housing conditions; extensive lead hazards; lack of abatement resources, landlord compliance and local enforcement capacity; and family eviction. During 1996-1998, the Kennedy Krieger Institute implemented a unique capitated Program for case management of Baltimore City children with blood lead concentrations (PbB) 919 2g/dL. The Program provided financial, housing, and social work assistance to facilitate relocation as a means of providing safer housing. Nearly half of the Program families relocated with direct assistance, and 28% relocated on their own. The Program evaluation examined the costs and benefits of relocation. Average relocation cost per child was relatively inexpensive (G$1,500). Average relocation time of 5 months (range G2 months to 912 months) was less than the 8-month average time to complete lead hazard control work in 14 city and state programs funded by U.S. HUD. Relocation was associated with (1) a statistically significant decrease in dust lead loadings on floors, windowsills and window troughs that persisted for one year, and (2) statistically significantly greater decreases in children_s PbB compared to children who did not relocate from untreated homes. Children relocated to housing that met current Federal residential dust lead standards had statistically significant decreases in blood lead levels. Visual inspection did not consistently identify relocation houses with dust lead levels below current Federal standards, indicating that dust testing should be an essential component of future programs. This will require additional resources for dust testing and possibly cleaning and repairs but is expected to yield additional benefits for children. The findings support recent U.S. CDC case management recommendations suggesting that permanent relocation to safer housing is a viable means to reduce children_s lead exposure. The benefits of relocation notwithstanding, 40% of families moved at least twice. Research is needed to better understand how to expedite relocation and encourage families to remain in safe housing. Relocation does not negate owners_ and health authorities' responsibilities to address lead hazards in the child's original house in order to protect future occupants.

Controlling residential lead hazards is critical for case management of lead poisoned children. To attain this goal, permanent relocation of the family is sometimes necessary or advisable for many reasons, including poor housing conditions; extensive lead hazards; lack of abatement resources, landlord compliance and local enforcement capacity; and family eviction. During 1996-1998, the Kennedy Krieger Institute implemented a unique capitated Program for case management of Baltimore City children with blood lead concentrations (PbB) 919 2g/dL. The Program provided financial, housing, and social work assistance to facilitate relocation as a means of providing safer housing. Nearly half of the Program families relocated with direct assistance, and 28% relocated on their own. The Program evaluation examined the costs and benefits of relocation. Average relocation cost per child was relatively inexpensive (G$1,500). Average relocation time of 5 months (range G2 months to 912 months) was less than the 8-month average time to complete lead hazard control work in 14 city and state programs funded by U.S. HUD. Relocation was associated with (1) a statistically significant decrease in dust lead loadings on floors, windowsills and window troughs that persisted for one year, and (2) statistically significantly greater decreases in children_s PbB compared to children who did not relocate from untreated homes. Children relocated to housing that met current Federal residential dust lead standards had statistically significant decreases in blood lead levels. Visual inspection did not consistently identify relocation houses with dust lead levels below current Federal standards, indicating that dust testing should be an essential component of future programs. This will require additional resources for dust testing and possibly cleaning and repairs but is expected to yield additional benefits for children. The findings support recent U.S. CDC case management recommendations suggesting that permanent relocation to safer housing is a viable means to reduce children_s lead exposure. The benefits of relocation notwithstanding, 40% of families moved at least twice. Research is needed to better understand how to expedite relocation and encourage families to remain in safe housing. Relocation does not negate owners_ and health authorities' responsibilities to address lead hazards in the child's original house in order to protect future occupants.

Objetivo. Determinar los niveles de plomo en sangre de los recién nacidos (RN) de menos de 12 horas de vida, en la ciudad de La Oroya. Material y métodos. Estudio descriptivo, transversal y prospectivo realizado entre junio de 2004 a junio de 2005 de una muestra de recién nacidos (RN) de La Oroya, se usó un cuestionario para la madre gestante y se determinó los niveles de plomo en sangre venosa (2 mL) utilizando la espectrofotometría por absorción atómica con llama de aire de acetileno. Los valores se expresan en microgramos de plomo por decilitro de sangre (μg/dL). Resultados. Se evaluó 93 RN; el nivel promedio de plomo en sangre fue de 8,84 ± 0,57 μg/dL. El 75,3% (70/ RN) tuvo niveles de plomo en sangre entre 6 a 10 μg/dL, y 24,7% (23 RN) tuvo más de 10 μg/dL. Los RN de madres que viven en La Oroya Nueva tienen menos niveles de plomo que los que viven en La Oroya Antigua (p=0,002). Conclusiones. Los RN de la ciudad de La Oroya presentan elevados niveles de plomo en sangre, por lo que se requiere iniciar programas de prevención en las madres gestantes para evitar futuros daños a la salud de los recién nacidos.

The adverse effects of lead exposure on children are well known. Low blood lead levels (BLL) produce neurodevelopmental delay and cognitive disorders. However, since BLL thresholds for adverse effects on children's health are not known, the children population at risk of excessive lead exposure still has to be identified. This study was aimed at evaluating BLL in a children population of Gran Canaria (Canary Islands, Spain). Up to our knowledge, this is the first study to report on BLL in this population. Lead was identified and quantified in blood samples of 120 children, by means of Graphite furnace atomic absorption spectrometry (GFAAS). Lead was undetected in 80% of samples; BLL was 1 to 5 g/dl in 15% of samples, and higher than 5 g/dl in more than 4% of samples. BLL values in the evaluated children were low and similar to those described for other populations in Western countries. However, samples with the highest contamination (those in percentile 95) reached BLLs as high as 5.2 g/dl. Positive associations were found between BLL and recent immigration (children adopted from non-western countries), and between BLL and parental smoking in children with low weight at birth. Since lead exposure in childhood may be a causative factor in adverse health trends-especially those involving the neurological system-and since threshold values for adverse lead effects are unknown, our finding that around 20% of the studied children had BLL higher than 1 g/dl are of concern. Enhancing preventive measures for reducing lead exposure in children from the Canary Islands deserves further study.

Objectives: The objective of this study was to investigate the zinc protoporphyrin/heme ratio (ZPP/heme) as a biomarker for chronic lead (Pb) poisoning in children with a history of high Pb exposure. Design and methods: ZPP/heme ratio was measured in blood samples from 78 children (44 females and 34 males) with persistent Pb exposure from Pb glazing of ceramics in a local cottage industry in the Andes Mountains of Ecuador. Results: Mean blood lead (PbB) level was 26.4 μg/dL (SD: 23.2; range: 4.0-107.0), and the mean ZPP/heme ratio was 152.4 μmol/mol (SD: 190.6; range: 36.0-1064.0). A regression analysis of PbB level and ZPP/heme ratio revealed a significant association (r = 0.761, p = < 0.0001), with the logZPP showing a higher correlation with PbB (r = 0.869, p = < 0.0001). The ZZP/heme ratio decreased significantly with increasing age (ANOVA, p = 0.030). The mean ZPP/heme ratios for females and males were 139.6 and 169.0 μmol/mol, respectively, and were not statistically different (t-test, p = 0.504). Conclusion: The elevated ZPP/heme ratios, coupled with high PbB levels observed in this cohort of Andean children of Pb-glazing workers, suggest chronic Pb intoxication and probable iron deficiency.

Niveles de plomo sanguíneo en madres y recién nacidos derechohabientes del Instituto Mexicano del Seguro Social. Salud Publica Mex 2000;42:391-396. Resumen Objetivo. Establecer la relación entre el nivel de plomo sanguíneo materno (PSM) y el de sangre en cordón umbilical (PSC) al momento del parto, así como determinar los principales predictores del PSM en derechohabientes del Instituto Mexicano del Seguro Social (IMSS), en el Distrito Federal (D.F.). Material y métodos. Se realizó un estudio transversal en el que se reclutaron voluntarias con embarazo normoevolutivo y se les tomaron muestras de sangre al momento del parto, en cuatro hospitales del IMSS en el D.F., de 1991 a 1993. Se tomó, además, muestra de sangre de cordón umbilical. Los datos fueron analizados mediante regresión lineal simple y múltiple. Resultados. Se estudiaron un total de 1 404 binomios madre-hijo; el promedio de edad de las madres fue de 25 años. La media de PSM fue 10.7 ± 6.5 µg/dl; no se encontraron variaciones significativas por hospital, edad o estado civil. Para el PSC la media fue de 10.4 ± 6.2 µg/dl. Por cada aumento en una unidad logarítmica de PSM, el PSC aumenta 0.62 (p<0.01) unidades logarítmicas. La correlación entre ambos fue de 0.61 (p<0.01). Los principales predictores de PSM fueron el uso de loza vidriada, el consumo de leche y jugo de naranja, estos últimos se asociaron inversamente con el PSM. Un 47% de las madres y 50% de los niños tuvieron valores su

The determination of blood lead levets was included in a Swiss population survey on cardiovascular risk factors in 1984-1985; 931 men and 843 women aged 25 to 75 years participated in the study. Mean blood lead levels (+SD) were 0.63 + 0.27 ~mole/liter for men and 0.44-+ 0.19 p.mole/titer for women, respectively, with a slight increase with age for both sexes. These values are below the maximum level recommended by the Commission of the European Community in 1977; 18 cases were found with blood lead higher than 1.5 ~mole/liter and in six of these, a professional exposure was suspected. Smoking habits, drinking habits, and consumption of dairy products were selected as lifestyle descriptors and educational level, occupational category, and size of the community as sociodemographic indicators. Smoking and alcohol consumption show a direct association with blood lead, consuming dairy products an inverse one. Occupation and level of education are significantly related to blood lead only for men, blue-collar workers and less-educated men being more exposed. A higher blood lead level in cities was only found for women presumably because they stay at home more of Len than men and are therefore more sensi6ve to local exposure. In a multiple stepwise logistic regression, the lifestyle indicators showed a consistently stronger effect on blood lead than sociodemographic indicators. For men, smoking has an effect on blood lead for blue-collar workers much stronger than that for nonindustrial employees and may compound in some way the professional exposure to lead. This stresses the fact that interactions between lifestyle and environmental factors on blood lead are significant, complex, and need further iavesfigation.

To evaluate lead exposure among children living in border communities, the states of Arizona and New Mexico in the United States (US), and the states of Sonora and Chihuahua in Mexico collaboratively requested that the Centers for Disease Control and Prevention (CDC) provide technical assistance to document pediatric blood lead levels (BLLs) in children living along this part of the US/Mexico border. Two studies were conducted to evaluate BLLs of children aged 1-6 years. In 1998, 1210 children were tested in the Arizona/Sonora study; in 1999, 874 children were tested in New Mexico/Chihuahua. Overall geometric mean BLL was 32.5 mg/l (95% Confidence Interval 31.5-33.5) with BLLs ranging from below limit of detection to 320.0 mg/l. Mean BLLs were higher among children living on the Mexican side of the border (43.2 mg/l) compared to those on the US side (22.3 mg/l). Mean BLLs ranged from 14.9 to 31.2 mg/l at the US sites and from 26.9 to 55.2 mg/l at the Mexican sites. This study used a convenience sample and cannot be considered representative of the general population. Nonetheless, the range of mean BLLs among the sites and especially the higher mean BLLs among children living in the border communities in Mexico suggests different exposures to lead and warrants further attention.

Lead exposure is a common public health problem. Exposure to the metal can cause hematological, gastrointestinal, rheumatological, endocrine, neurological and renal problems in humans. However, effects on the thyroid gland are controversial. We retrospectively investigated thyroid function parameters in 65 adult males who had been occupationally exposed to lead. We then compared the findings with those of 60 male patients who had no history of lead exposure or thyroid abnormalities, who served as the control group. The mean ages of the lead-exposed workers and the controls were 34.3 ± 7.9 and 32.9 ± 6.6 years respectively. Blood lead levels in the lead-exposed workers were significantly higher than in the control group. The lead-exposed workers were assigned to one of three groups according to their blood lead levels, as follows: 40–59 μg/dl, 60–79 μg/dl, or 80 μg/dl and above. Thyroid Stimulating Hormone (TSH) levels in the 80 μg/dl and above group were significantly higher than in...

Background, aim, and scope Lead, a major contaminant, is highly used in paint manufacturing due to its anticorrosive properties. Recent reports indicated high lead content among Indian paints used for commercial purposes. Painters are continuously exposed to these lead containing paints during painting of both commercial as well as

This work documents ambient lead dust deposition values (lead loading) for the boroughs of New York City in 2003-2004. Currently, no regulatory standards exist for exterior concentrations of lead in settled dust. This is in contrast to the clearance and risk assessment standards that exist for interior residential dust. The reported potential for neurobehavioral toxicity and adverse cognitive development in children due to lead exposure prompts public health concerns about undocumented lead sources. Such sources may include settled dust of outdoor origin. Dust sampling throughout the five boroughs of NYC was done from the top horizontal portion of pedestrian traffic control signals (PTCS) at selected street intersections along main thoroughfares. The data (n ¼ 214 samples) show that lead in dust varies within each borough with Brooklyn having the highest median concentration (730 mg/ft 2), followed in descending order by Staten Island (452 mg/ft 2), the Bronx (382 mg/ft 2), Queens (198 mg/ft 2) and finally, Manhattan (175 mg/ft 2). When compared to the HUD/EPA indoor lead in dust standard of 40 mg/ft 2 , our data show that this value is exceeded in 86% of the samples taken. An effort was made to determine the source of the lead in the dust atop of the PTCS. The lead in the dust and the yellow signage paint (which contains lead) were compared using isotopic ratio analysis. Results showed that the lead-based paint chip samples from intact signage did not isotopically match the dust wipe samples taken from the same surface. We know that exterior dust containing lead contributes to interior dust lead loading. Therefore, settled leaded dust in the outdoor environment poses a risk for lead exposure to children living in urban areas, namely, areas with elevated childhood blood lead levels and background lead dust levels from a variety of unidentified sources.