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PubMed1990

Determination of numbers of lead-exposed U.S. children by areas of the United States: an integrated summary of a report to the U.S. Congress on childhood lead poisoning.

In response to Congressional mandate and under the aegis of the Federal Agency for Toxic Substances and Disease Registry (ATSDR), a comprehensive report to Congress on childhood lead poisoning in the United States was prepared. We have examined numbers of lead-exposed U.S. children by socioeconomic/demographic strata for children 0.5 to 5 years of age; by children in U.S. lead-screening programs; and by enumerations of children 0.5 to 5 years old in the oldest (i.e., highest paint lead and lead plumbing) housing. Using blood lead (PbB) prevalence projection modeling and data of the Second National Health and Nutrition Examination Surgery (NHANES II), it is estimated for 1984 that 2.4 million black and white children 0.5 to 5 years old in metropolitan U.S. had PbB levels greater than 15 micrograms/dL. For all races and the entire nation, we estimate 3 to 4 million children will have PbB levels greater than 15 micrograms/dL. Inner-city, low-income children have the highest prevalences of PbB levels above this criterion level, but sizable numbers of all strata of children have elevated PbB levels when considering both base populations and prevalences for the specific strata (total of 30 strata). Lead screening programs indicate much lower numbers of exposed children compared to NHANES II-based projections, for various reasons that allow programs to underestimate true prevalences. Analysis of 1980 U.S. Census Bureau housing data for 318 standard metropolitan statistical areas show that 4.4 million children 0.5 to 5 years old live in the oldest U.S. housing (pre-1950). Of these, most are actually in the more affluent socioeconomic strata.

Child, Preschool↗
PubMed1996

Moderate lead poisoning: trends in blood lead levels in unchelated children.

The appropriate clinical management of children who are moderately poisoned with lead (Pb) is under active investigation. To determine the pattern of change in blood Pb (BPb) levels in the absence of chelation therapy, we followed moderately Pb-poisoned children (initial blood Pb levels 1.21-2.66 mumol/l or 25-55 micrograms/dl) for 6 months with repeated BPb level measurements. Chelation therapy was not administered because all the children had negative lead mobilization tests indicating limited response to the chelating agent, calcium disodium edetate (CaNa2EDTA). Eligible children received the following interventions: notification of the health department to remediate lead hazards; reinforced educational efforts about the toxicity sources and treatment of Pb during 10 clinic and 3 home visits; and iron therapy for children with ferritin levels less than 16 micrograms/l. To quantify the lead paint hazards in the home, we combined a visual rating of the surfaces (intact to peeling) with an X-ray fluorescence (XRF) measurement of the lead content of the painted surface. The sum of these assessments is termed the home environmental score (HES). Data were analyzed from 79 children. BPb levels declined by 27%, on average, over 6 months. HES was correlated with BPb at enrollment, but neither the initial nor later HES measurements predicted BPb at other time points. The HES was highest at enrollment and declined by 50% and 75% at the second and third home visits, respectively. However, only a minority of the children (20%) achieved an HES of 0, indicating no lead paint hazards at home. Despite some ongoing Pb exposure, a parallel fall in BPb levels was observed in subgroups of children with either initially low or high HES (above or below the median HES of 37). Iron status did not account for the change in BPb levels. These data provide evidence that our measure, the HES, is quantifiably related to BPb levels in children, that this correlation is significant only prior to intervention; and that BPb levels decline in children who are moderately poisoned with Pb after they are enrolled in a comprehensive intervention program, even in the absence of chelation therapy and in the presence of ongoing lead paint exposure and Fe deficiency.

Chelation Therapy↗
PubMed2003

Children's blood lead levels after the phasing out of leaded gasoline in Shantou, China.

Shantou, a city in the People's Republic of China, has a central urban population of approximately 700,000 and a large number of registered vehicles (motorcycles = 256,600; other motor vehicles = 261,000). Shantou is designated as 1 of the 5 Special Economic Zones in China. The use of leaded gasoline was prohibited in the city at the end of 1998. Blood samples for lead analysis were collected from children aged 1-5 yr during the summers of 1999-2001, and the samples were analyzed using graphite furnace atomic absorption spectrometry. In 1999, 44.3% (147/332) of the children had mean blood lead levels in excess of 100 microg/l. The percentage of children with blood lead levels that exceeded 100 microg/l was reduced to 35.8% (227/635) and 23.0% (105/457) in 2000 and 2001, respectively. Average blood lead levels declined from 104 microg/l, to 94 microg/l, and 79 microg/l during the 3-yr period, respectively; the respective concordant geometric means were 97 microg/l, 85 microg/l, and 71 microg/l. Mean blood lead levels for the children studied decreased significantly (p < 0.05) every year. Among all children tested during the 3-yr period, there were no significant differences by gender and no significant differences between children who were between the ages of 2 and 3 yr; however, those who were 4 yr of age had blood lead levels that were significantly (p < 0.05) higher than levels in those 2 and 3 yr of age.

Carcinogens, Environmental↗
PubMed1976

Relationships between lead absorption and peripheral nerve conduction velocities in lead workers.

The motor sensory, and mixed nerve conduction velocities of median and posterior tibial nerves were measured in 39 lead workers whose blood lead (PbB) concentrations ranged from 2 to 73 mug/100 g with anaverage of 29 mug/100 g. The PbB concentrations significantly correlated with the maximal motor nerve conduction velocities (MCV) and mixed nerve conduction velocities (MNCV) of the median nerve in the forearm and with the MCV of the posterior tibial nerve. Erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity correlated similarly with the MCV and MNCV of the median nerve in the forearm, and the 24-hour urinary lead excretion following the intravenous administration of CaEDTA (20 mg/kg) (lead mobilization test) correlated with the MNCV. But no parameter correlated with the sensory nerve conduction velocities. By multiple regression analysis, a combination of the three parameters of lead absorption was found to correlate significantly with the MCV and MNCV of the median nerve in the forearm. The MCVs of the median and posterior tibial nerves in lead workers were significantly delayed in the PbB range of 29-73 mug/100 g (mean 45), in the lead mobilization test range from 173 to 3,540 mug/day (mean 973), and the ALAD activity range from 4.4 to 19.4 u. (mean 14.0), respectively.

Absorption↗
PubMed1998

Predictors of blood lead concentrations in the lead-free gasoline era.

OBJECTIVES: Blood lead concentrations in a Danish reference population were related to information from an extensive questionnaire on work, environment, and life-style. METHODS: Data were gathered for 209 persons by means of a questionnaire and blood lead analyses. RESULTS: The mean concentration of lead in blood was 0.167 micromol/l (ie, significantly lower than in previous studies). This finding is in accordance with the fact that less than 10% of the gasoline used in Denmark contains lead additives (up to 0.15 g/l). An important finding was that the well-documented predictors for lead in blood at higher concentration levels, such as age, gender, menopausal status, and intake of alcohol, are still valid in a low-level exposure situation. In addition, a strong and negative correlation was found between blood lead concentrations and dietary supplementation with vitamins and minerals. CONCLUSIONS: The present data indicate that lead exposure may still constitute a health risk in a small proportion of adult men and postmenopausal women.

Adolescent↗
PubMed2001

Bite the bullet: lead poisoning after ingestion of 206 lead bullets.

A 45-y-o male with a history of schizophrenia was admitted to a local VA psychiatric unit. Five days later, endoscopy due to abdominal pain, gastrointestinal bleeding and blood hemoglobin of 5.6 g/dL revealed bullets in the stomach. On subsequent radiograph, > 50 bullets were visualized in the stomach and intestines. Poison Center recommendations included whole bowel irrigation and a blood lead level. After poor results with gastrointestinal decontamination and a repeat radiograph showing > 100 cartridges, surgical intervention was considered but not performed due to perceived risk of bullet detonation from electrocautery. The blood lead was reported as 391 mcg/dL. Calcium EDTA therapy was initiated, followed by aggressive gastrointestinal decontamination. Four days of whole bowel irrigation facilitated passage of 206 cartridges over the next 10 days. The patient was discharged on a 14-day course of 600 mg Succimer tid to treat the bone lead deposits and blood lead level of 49 mcg/dl. An outpatient visit 6 w later showed the blood lead level had dropped to 24 mcg/dl. Aggressive gastrointestinal decontamination and calcium EDTA and Succimer administration successfully treated an ingestion lead bullets and the resulting lead poisoning.

Antidotes↗
PubMed1975

The influence of experimental distemper infection on the distribution of lead in dogs previously subacutely intoxicated with lead carbonate.

The ability of experimental canine distemper infection to mobilize body lead deposits has been studied in Beagle dogs previously subacutely intoxicated with lead carbonate. For comparative purposes dogs were included which had either received lead only or distemper only or remained undosed. It was found that in dogs predosed with lead, distemper infection resulted in a significant increase in lead levels in blood and urine; this coincided with the peak body temperatures reached on the third day post infection. It was also found that the lead content of the liver and bone of these dogs was considerably higher than that of dogs receiving lead alone; at the same time bone phosphorus showed a marked decrease while bone calcium values remained similar to undosed controls.

Animals↗
PubMedDate not supplied

Lead poisoning: I. Some clinical and toxicological observations on the effects of occupational lead exposure among firearms instructors.

Lead poisoning continues to be a common occupational disease in many countries. During the past two decades, poisoning presenting with overt clinical symptoms has become less frequent because of improvement in control of exposure, and attention has been focused on subtle biochemical and "subclinical" manifestations of lead toxicity. Firearms instructors constitute an occupational group at risk for excessive exposure to lead from the firing of arms in shooting galleries. This paper summarizes clinical and toxicological observations among lead-exposed firearms instructors and illustrates the wide spectrum of clinical and laboratory abnormalities that may occur in this occupational group. As clinical research has advanced, significant biochemical and clinical aberrations have been detected at progressively lower blood lead levels both among occupationally exposed adults and among children who are exposed to lead in the general environment. The latter is of great public health concern and has spurred efforts worldwide to reduce human exposure to lead to an absolute minimum.

Adult↗
PubMedDate not supplied

Characteristics of lead adaptation in a rat kidney cell line. I. Uptake and subcellular and subnuclear distribution of lead.

Two sublines of normal rat kidney cell (NRK 52-E) that are resistant to 5 and 10 microM lead nitrate have been developed and characterized. The cellular and nuclear uptake of 210Pb, as well as the subnuclear distribution, was unchanged by lead adaptation: it remained at values of 2.3-6.6 pmole 210Pb/microgram protein/h. Also no difference in the slope of the curve of the uptake rate of the three cell types could be detected. Studies of the nuclear uptake of 210Pb showed that in both normal and lead-adapted cells the major lead fraction was associated with the chromatin and mostly (63-67%) with the nuclear proteins. Electron microscopic studies demonstrated that particulate lead was taken up in all lead-exposed cells. It was concluded that development of resistance to lead does not arise from a reduced rate of cellular uptake, from increased excretion, or from changes in nuclear uptake or in the subnuclear distribution within the cells.

Animals↗
PubMed2000

Subclinical neurophysiological effects of lead: A review on peripheral, central, and autonomic nervous system effects in lead workers.

BACKGROUND: The peripheral nerve conduction velocity (NCV), distribution of nerve conduction velocities (DCV), somatosensory, visual, and brainstem auditory evoked potentials (SEP, VEP, and BAEP, respectively), event-related potential (P300), computerized static posturography with spectral analysis (postural balance), and electrocardiographic R-R interval variability (CV(RR)) with spectral analysis appear to be promising techniques for assessing subclinical effects of lead on the peripheral, central and autonomic nervous systems. This article presents an overview of research addressing subclinical neurophysiological effects of lead in workers exposed to lead. METHODS: We reviewed 102 articles to examine the effects and dose-effects relationships of lead on peripheral, central, and autonomic nervous system function together with reversibility of the effects, interaction between lead and other metals, and relative sensitivity and specificity of each technique. Background and methodology were also reviewed. RESULTS AND CONCLUSION: Available data suggest that, on a group basis, the reduction in the NCV, together with the effects on the P300 latency, postural balance, and CV(RR), occurs at a mean blood lead concentration (BPb) as low as 30-40 microg/dL; the effects on the latencies of the short-latency SEP, VEP, and BAEP, as well as the DCV, start at a BPb as low as 40-50 microg/dL. Further cross-sectional and preferably prospective studies by using each of those methods are needed to establish more precise dose-effects (and response) relationships of lead.

Autonomic Nervous System↗
PubMed1984

Lead in finger-bone analysed in vivo in active and retired lead workers.

In 75 active lead workers the median lead level in finger-bone (bone-Pb), as determined in vivo by an X-ray fluorescence method, was 43 micrograms/g (range less than 20-122). In 32 retired workers the median level was even higher, 59 micrograms/g (range less than 20-135), which indicates a slow turnover rate of lead in finger-bone. This was confirmed in 18 of the "active" workers, in whom bone-Pb was studied in connection with an exposure-free period. In spite of a significant decrease in blood-lead levels (B-Pb), no systematic change of bone-Pb occurred. There was an increase of bone-Pb with time of employment, but with a large interindividual variation. No association was found between bone-Pb and present B-Pb in the active lead workers. However, in the retired ones, B-Pb rose with increasing bone-Pb. The bone-lead pool thus causes an "internal" lead exposure.

Adult↗
PubMed1989

Parental occupational lead exposure and lead concentration of newborn cord blood.

The purpose of this study was to determine the influence of parental occupational lead exposure on the lead levels of newborn cord blood in the Taipei area. From September 1984 to June 1985, 5,000 pregnant women voluntarily participated in the study at the Taipei Municipal Maternal and Child Hospital. Each woman was interviewed regarding her and her husband's occupational exposures; 2,948 successfully delivered healthy newborns, and cord blood samples were obtained using Terumo Venoject, and 242 samples were analyzed by graphite furnace atomic absorption spectrometry using an Instrumentation Laboratory 251 instrument. Nine cord blood samples were from newborns with both parents exposed, 26 samples had maternal exposure only, 105 samples had paternal exposure only, and 102 were nonexposed. The results showed that the average lead level of cord blood with both parents exposed was 8.9 +/- 2.9 micrograms%, maternal exposure 9.0 +/- 3.8 micrograms%, paternal exposure 8.3 +/- 3.4 micrograms%, and 6.9 +/- 3.2 micrograms% in the nonexposed group. There were significant differences between the nonexposed and the maternal exposure groups, and also between the nonexposed and paternal exposure groups. All 26 maternal exposures were from lead soldering operations. Multivariate analysis revealed that, after control of father's exposure status, newborn cord blood lead level increased 0.27 micrograms% for each hour the mother spent on lead soldering during a normal working day, thus suggesting that soldering during pregnancy may be hazardous to newborns. Paternal contribution to the cord blood lead levels seemed to be through either working at home with the pregnant mother also at home or bringing work clothes home for laundering.

Adolescent↗
PubMed1995

Time trend and determinants of blood lead levels in a Swiss population over a transition period (1984-1993) from leaded to unleaded gasoline use.

This study analyzes the trend and determinants of blood lead levels in a Swiss region (population 770,000) over the 10-year period following the introduction of unleaded gasoline in 1985. The consumption of unleaded fuel increased rapidly, accounting in 1988 for 36% and in 1992 for 65% of all gasoline sales. Blood lead levels were measured in three representative samples (n = 1700) of the adult population within the framework of a health examination survey carried out in 1984/1985, 1988/1989, and 1992/1993. The geometric mean blood lead levels were, respectively, 0.59, 0.42, and 0.33 mumole/liter in men, 0.41, 0.29, and 0.25 mumole/liter in women. Similar trends have been observed across all age groups, occupational classes, and categories based on smoking, drinking, and dietary habits. The overexposure of city residents, in comparison to village residents, fades out over the observation period. These findings suggest that the changeover from leaded to unleaded gasoline has been the major cause of the blood lead decline. Wine drinking, cigarette smoking, and age appear to be significant determinants of blood lead for both sexes in all three surveys. In contrast, the association is inverse for milk consumption. The multivariate regression analysis shows that wine drinking remains the most important predictor of blood lead, whereas the influence of age increases with time and overcomes the effect of smoking in the third survey.

Adult↗
PubMed1990

Predictors of tooth-lead level with special reference to traffic. A study of lead-exposure in children.

Possible predictors of the lead burden of children were investigated in a low-exposure area. A total of 1302 school children in the first form within the municipality of Aarhus, Denmark, donated deciduous teeth for determination of the lead concentration in the circumpulpal dentin. The families were interviewed on possible sources of lead. Present and former addresses of residences and day-care institutions were obtained, and the traffic intensity was estimated at each of these addresses. Children with a high lead burden resided significantly more often in heavily-travelled streets than children with a low burden, but only during their first 3 years of life. The increased risk for a high lead burden was related to the traffic intensity in a dose-response manner. Further, children with a high lead burden more often exhibited pica, their mothers smoked more during pregnancy, and their fathers were more likely to work at a garage or shipyard. In a logistic multivariate regression, such parental occupation increased the risk for a high lead burden 1.5-fold (ORadj; P = 0.03), whereas tobacco and traffic each were of borderline significance (ORadj = 1.4, P = 0.08).

Air Pollutants↗
PubMed1976

Relationship between lead concentration in blood and biological response for porphyrin metabolism in workers occupationally exposed to lead.

The biological responses of the heme biosynthesis pathway in male workers moderately exposed to lead are discussed in relation to the concentration of lead in the blood. The level of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) activity in the group of lead-exposed workers was remarkably reduced while the level of erythrocyte protoporphyrin (Proto) in them was strikingly increased, compared to normal levels. On the other hand, the amounts of hemoglobin (Hb) and urinary delta-aminolevulinic acid (ALA) in the group of lead-exposed workers kept the normal levels. In the workers moderately exposed to lead, the log of erythrocyte Proto level was closely correlated to the blood lead level and the sensitivity of the Proto test was almost equal to that of erythrocyte ALA-D test. It was observed that the erythrocyte Proto was remarkably increased even in lead-exposed workers whose ALA excretion into the urine was in the range of normal level.

Aminolevulinic Acid↗
PubMedDate not supplied

Effect of soil pollution with metallic lead pellets on lead bioaccumulation and organ/body weight alterations in small mammals.

Using small mammals as bioindicators, the bioavailable status and ecotoxicity of lead was investigated in an acidic sandy soil environment polluted with metallic lead pellets from shotgun ammunition. Average concentrations of lead in kidney, liver and bone tissue of wood mice (Apodemus sylvaticus), bank voles (Clethrionomys glareolus), and shrews (Sorex araneus) were strongly elevated, compared to tissue levels of conspecifics collected from an adjacent unpolluted area. All shrews and some bank voles collected from the shooting range exceeded the critical renal Pb concentration of 25 micrograms/g dry weight, considered diagnostic of lead intoxication in mammals. The geometric mean renal Pb concentration in shrews was 270 micrograms/g dry weight, with an upper range of more than 1,000 micrograms/g. The population of shrews and bank voles from the shooting range also showed a significantly increased average relative kidney weight (kidney-to-body weight ratio), which is indicative of lead poisoning. The results suggest that metallic lead pellets deposited in an acidic sandy soil are transformed to a chemical form of lead, probably Pb2+, which is toxic to organisms and which can readily enter the terrestrial food chain.

Analysis of Variance↗
PubMed1982

Persistent protoporphyrinemia in hereditary porphobilinogen synthase (delta-aminolevulinic acid dehydrase) deficiency under low lead exposure. A new molecular basis for the pathogenesis of lead intoxication.

For several years, a 4-12-fold increase of the upper normal limit in erythrocyte protoporphyrin concentrations persisted in two men 34 and 39 years of age who were chronically exposed to lead. We are dealing with a zinc protoporphyrinemia in both cases, without lead intoxication or anemia. The 34-year-old had been a regular blood donor for 10 years and had already been treated for iron deficiency several times. Hemoglobin, red cell counts, hematocrit, and iron were at the lower normal limit. The activity of porphobilinogen synthase (PBG-S), uroporphyrinogen-synthase and -decarboxylase as well as urinary porphyrin precursors and porphyrin excretion were normal. Protoporphyrinemia was said to be due to a prelatent/latent iron deficiency. In the 39-year-old, the activity of PBG-S was lowered to 388 mumol/1 . h, as compared to the mean of controls (1,190 +/- 210, x +/- SD, n = 50), in connection with a slightly elevated excretion of delta-aminolevulinic acid and coproporphyrin in the urine and a high-normal blood lead level. In his family there was no history of either a protoporphyrinemia or a hematological disturbance. Six of eight family members in three generations showed a diminished activity of PBG-S: 600 +/- 160, P less than 0.001 compared to controls. These family members are heterozygous with regard to the PBG-S deficiency; they are clinically unobtrusive in comparison to homozygotes with an acute prophyria syndrome. Activation by zinc and reactivation by dithiothreitol were normal in contrast to PBG-S from patients with lead intoxication. The cause of biochemical symptoms of subclinical lead intoxication developed by the propositus is probably due to the hereditary PBG-S deficiency which sensitizes him to low-level lead exposure. The determination of red cell PBG-S activity can be recommended as a test detecting heterozygotes. The hereditary PBG-S deficiency is recognized as a new molecular basis for the pathogenesis of lead intoxication.

Adult↗
PubMed2001

The determination of low lead levels in the bone of lead-depleted mice by graphite furnace atomic absorption spectrometry.

Low lead levels in the femurs of mice fed with a lead-depleted diet have been determined by use of electrothermal atomic absorption spectrometry with Zeeman-effect background correction. The method is based on the use of Mg(NO3)2/Pd as matrix modifier which enables significant reduction of the spectral interferences prevalent if chemical modifiers based on NH4H2PO4 with either Ca or Mg are used for samples rich in Ca3(PO4)2 matrix. The method was developed and validated by use of the NIST standard reference material 1486 bone. Bones were decomposed in a pressurized microwave-heated system using 70% nitric acid. Forty-three mice femurs, with a mass of 74.62 +/- 12.54 mg, were dissolved in concentrated nitric acid. The lead results found in SRM 1486 (1.25 +/- 0.15 microg g(-1), n = 9) were in good agreement with the certificate (1.335 +/- 0.014 microg g(-1)). Recoveries of 200 ng lead added to the SRM before or after digestion were 99.0 +/- 1.4% and 98.5 +/- 1.6%, respectively. The lead detection limit in bone samples is 0.06 microg g(-1) dry mass. This method is, therefore, suitable for the determination of very low lead levels (0.06-0.20 microg Pb kg(-1) bone) in the femurs of mice fed a diet with lead level of < 20 microg kg(-1).

Animals↗