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PubMedDate not supplied

Blood lead levels in Toronto children and abatement of lead-contaminated soil and house dust.

South Riverdale in Toronto, Canada, underwent a lead-abatement program. In 1988, lead-contaminated soil was replaced at 970 properties, and in 1989, professional housecleaning for lead removal was conducted in 717 households. The effect of "abatement" on blood lead levels in young children was investigated. Data were analyzed from 12 cross-sectional blood-screening surveys that were conducted during an 8-y period in South Riverdale and in two comparison areas. Responses regarding behavioral, household, lifestyle, neighborhood, and environmental factors, all of which were gleaned from associated questionnaires, were also analyzed. Response rates varied between 32% and 75%. During the years between 1984 and 1992, blood lead decreased in all study areas. There appeared to be a minimal blood lead level of 2-3 micrograms/dl for urban Ontario children who were less than 6 y of age. The significant difference between South Riverdale and the control areas disappeared by 1992. Although abatement activity in South Riverdale was associated with an accelerated decline in blood lead levels, it was difficult to distinguish this from effects of decreased Toronto air lead levels or decreased smelter emissions. Within South Riverdale, abatement appeared to be associated with a slower decline in blood lead levels over time, likely the result of selection bias, soil mixing, or recontamination from the smelter. No difference was observed between the separate effects of housecleaning or soil replacement. The findings could neither strongly support nor refute beneficial effects of abatement.

Analysis of Variance↗
PubMed2001

Lead accumulation in human ovarian follicular fluid, and in vitro effect of lead on progesterone production by cultured human ovarian granulosa cells.

Lead content of ovarian follicular fluid obtained from 23 women was determined by atomic absorption spectrophotometry. In an in vitro experiment the direct effect of lead on the morphology and on progesterone (P) production by cultured granulosa cells of six women was investigated. Follicular fluid and granulosa cells were obtained from follicular aspirates of women undergoing in vitro fertilization (IVF) and embryo transfer (ET). Granulosa cells were cultured for 48 h to form monolayers in the presence or absence of lead acetate (100-1,600 microM). The effect of the metal proved to be concentration dependent. While 100-400 microM lead had no effect on the integrity of the monolayer, concentrations as high as 800 microM or higher inhibited cell adhesion and induced detachment of cells. The lead levels found in follicular fluid were 11.29 +/- 1.38 microg/L (0.056 +/- 0.007 microM). With lead in vitro at 1,600 microM (331.5 mg/L) there resulted a significant decrease in P production by granulosa cells. This concentration is very much higher than that measured in follicular fluid of IVF/ET patients, specifically nonexposed to lead, and even higher than mean blood levels reported by others in high exposure groups. In conclusion, lead seems not to exert a specific effect on the steroidogenesis by cultured human granulosa cells. Therefore, the lead levels measured in the ovarian follicular fluid seem not to pose a hazard with respect to progesterone secretion by the ovary.

Adult↗
PubMed1985

Factors affecting blood lead concentrations in the UK: results of the EEC blood lead surveys, 1979-1981.

Surveys of blood lead concentrations carried out in the UK under the EEC screening programme for lead covered 8500 people. Blood lead analyses were subject to stringent quality assurance schemes. Significant variations in blood lead were found with age and sex, smoking and drinking habits, social class (in children), age of dwelling and geographical location but not with social class in adults, or with ethnic origin. Blood lead concentrations in childhood exposed to leadworks fell in 1981 following efforts to reduce emissions and improve workers' hygiene. Levels in those living near major roads were not very different from those in the general population in the same area. The highest blood lead concentrations were related to plumbosolvent water; lower levels in 1981 confirmed the effectiveness of remedial water treatment. Broadly similar effects of personal, social and environmental factors on blood lead have been found in other major studies. The findings that several geographical, environmental and personal factors were significantly related to the blood lead concentrations of children and adults have implications for all studies of blood lead concentrations in the general population.

Adult↗
PubMed2001

Genes upregulated in lead-resistant glioma cells reveal possible targets for lead-induced developmental neurotoxicity.

Identifying genes upregulated in lead-resistant cells should give insight into lead toxicity and cellular protective mechanisms and may also result in identification of proteins that may be useful as biomarkers. Glial cells are thought to protect neurons against heavy metals. Rat glioma C6 cells share many properties of normal glial cells. To identify and analyze genes upregulated in a lead-resistant variant, PbR11, suppression subtractive hybridization (SSH) between mRNAs of wild-type and PbR11 cells was performed. Sequencing and database searches identified three genes, thrombospondin-1, heparin sulfate 6-sulfotransferase, and neuropilin-1, which play important roles in angiogenesis and axon growth during development. Two genes, HSP90 and UBA3, are involved in the ubiquitin-proteosome system. One gene was identified as that of a rat endogenous retrovirus and another, 2C9, is a transcript expressed in fos-transformed cells. PbR11 also overexpresses c-fos. Expression of these genes and effects of short-term lead exposure (24 h, up to 600 microM) on their expression in C6 cells was examined. The rat endogenous retrovirus and 2C9 are expressed only in PbR11 cells, and show no expression, either constitutive or lead-induced, in wild-type C6 cells. HSP90 is expressed at low level constitutively in C6 cells, but can be induced in a dose-dependent manner by lead. In contrast, thrombospondin-1 is repressed in a dose-dependent manner by lead. The other genes (HS6ST, neuropilin, and UBA3) show low constitutive expression and are neither upregulated nor downregulated by exposure to lead. We suggest that neuropilin-1, heparin sulfate 6-sulfotransferase, and thrombospondin-1 may be important targets for lead-induced developmental neurotoxicity.

Animals↗
PubMed1996

Serial defibrillation lead impedance in patients with epicardial and nonthoracotomy lead systems.

INTRODUCTION: The stability of implantable cardiac defibrillation lead impedance subsequent to implantation has not been reported and may have important clinical implications. The objective was to characterize the incidence and degree of impedance changes occurring after implantation of defibrillation lead systems. METHODS AND RESULTS: The study cohort consisted of patients who received epicardial or nonthoracotomy lead systems. Defibrillation impedance was recorded at implantation, prior to hospital discharge (predischarge), and during follow-up. For each individual the magnitude of the impedance change relative to implantation was characterized. Among patients with an epicardial system, a significant decrease in impedance was observed at predischarge (mean 9.3 omega). The magnitude of the decrease was large in 39% and moderate in 31% of individuals. Subsequently, a gradual rise in mean impedance was apparent. At 18-21 months postimplantation, impedance was significantly increased relative to implantation (mean 6.8 omega). At this time, the magnitude of the increase was large in 46% and moderate in 23% of patients. Among patients with a nonthoracotomy lead system including a subcutaneous patch, a significant decrease in mean impedance was observed at predischarge (mean 3.5 omega). The magnitude of the decrease was large in 8% and moderate in 50% of individuals. Subsequently, a gradual rise in impedance was apparent. At 5-6 months, it was significantly increased relative to implantation (mean 2.3 omega). The magnitude of the increase was large in 10% and moderate in 33% of patients. Among the group of patients whose nonthoracotomy lead system did not include a subcutaneous patch, there was no significant change in mean impedance at predischarge relative to implantation. In subsequent intervals, a gradual rise was apparent. At 5-6 months, impedance was significantly increased relative to implantation (mean 4.3 omega). The magnitude of the increase was large in 16% and moderate in 47% of individuals. CONCLUSION: Significant changes in defibrillation lead impedance occur after implantation of epicardial and nonthoracotomy defibrillation lead systems. These data may serve as a standard for identifying the anticipated maximum change in lead impedance and thus may be useful as a tool for recognizing problems with defibrillation lead integrity.

Defibrillators, Implantable↗
PubMed1981

Determination of lead in plasma and studies on its relationship to lead in erythrocytes.

Plasma lead concentrations were determined in 103 subjects, including lead workers and those not occupationally exposed to lead. The plasma lead concentrations in each blood lead group were about half those previously reported, and this difference was shown to be due to the use of heparin instead of ethylenediaminetetra-acetic acid (EDTA) as the anticoagulant. The method for the determination of lead in plasma is detailed and its accuracy discussed. The plasma lead concentration was found to increase with the erythrocyte lead concentration, the mean equilibrium ratio between the two being about 0.74%. The effect of a sudden disturbance of the equilibrium condition on this ratio was investigated. This work supports the view that whole blood lead concentrations should be corrected for haematocrit.

Blood Specimen Collection↗
PubMed1995

Evaluation of lead exposure in workers at a lead-acid battery factory in Korea: with focus on activity of erythrocyte pyrimidine 5'-nucleotidase (P5N).

OBJECTIVE: To evaluate lead exposure among lead-acid battery workers in Korea, to evaluate in more detail the erythrocyte pyrimidine 5'-nucleotidase (P5N) test for lead exposure, and to evaluate the abnormal accumulation of erythrocyte pyrimidine nucleotides in the battery workers. METHODS: Activity of P5N and other biological variables were examined in 66 exposed workers in a lead-acid battery factory and in 26 non-exposed workers in Korea. RESULTS: At the factory the time-weighted average of 13 (72%) of 18 air samples for lead exceeded 0.05 (range 0.012-0.468) mg/m3. Blood lead concentration (PbB) in 39 of the 66 exposed workers was above 40 micrograms/dl, and the mean (SD) PbB in the exposed group was 45.7 (15.7) micrograms/dl. Compared with the nonexposed group, free erythrocyte protoporphyrin in the exposed group was significantly increased, whereas erythrocyte P5N activity and activity of erythrocyte delta-aminolevulinic acid dehydratase (ALAD) were significantly inhibited. Erythrocyte P5N activity had valid correlation biologically with PbB and with other biological variables, such as ALAD activity. In 28 exposed workers, the concentration of erythrocyte pyrimidine nucleotides (uridine 5'-diphosphate-glucose and cytidine 5'-triphosphate) correlated inversely with P5N activity and positively with PbB. CONCLUSIONS: These findings show that the depression of erythrocyte P5N activity by lead exposure results in the accumulation of erythrocyte pyrimidine nucleotides. In general, the standard analysis of PbB performed in laboratories around the world remains the most useful index of recent exposure. The results indicate that the erythrocyte P5N activity test provides supporting evidence of lead exposure and shows the effect of lead on nucleotide metabolism.

5'-Nucleotidase↗
PubMed1982

Effects of a nonabsorbable chelating resin on lead absorption, elimination, and accumulation in the rat. Resin effects on lead disposition.

In rats, oral administration of lead-chelating resin (Chelex-100) reduced the absorption of an oral lead dose (10 mg/kg) when both doses were given at approximately the same time. The same oral resin did not reduce blood lead concentrations when administered after the lead dose had been absorbed or after systemic lead administration (1 mg/kg, intracardiac), indicating that the resin did not influence lead elimination. As a dietary supplement the resin was also ineffective in reducing blood and kidney lead concentrations in rats exposed to lead in drinking water. Thus, the possible therapeutic uses of this lead-chelating resin may be limited.

Animals↗
PubMed1990

Methods for reducing lead exposure in young children and other risk groups: an integrated summary of a report to the U.S. Congress on childhood lead poisoning.

As part of a Congressionally mandated report on U.S. childhood lead poisoning prepared by the Federal government (U.S. Agency for Toxic Substances and Disease Registry [ATSDR]), the authors have analyzed the relative effectiveness of measures to reduce source-specific lead exposure of U.S. children. An integrated overview of this analysis is presented in this article. Two national actions, the Federally mandated phasedown of lead in gasoline by the U.S. Environmental Protection Agency and the voluntary phasedown of lead use in domestic food can production, are examples of centrally directed initiatives that have been relatively successful in limiting childhood lead exposure in the U.S. Efforts to abate lead-based paint exposure of children have largely failed. This is especially true for the nation's 21 million residential units with the highest lead content paint. Similarly, abatement of lead exposure from contaminated dusts and soils has generally been unsuccessful. Comprehensive measures to reduce lead exposure from drinking water in residences and public facilities, e.g., elementary schools, are only now being promulgated or implemented. The full extent of their effectiveness remains to be demonstrated. There are many miscellaneous but potentially severe exposure sources that are difficult to control but require attention, such as poorly glazed foodware and ethno-specific preparations.

Air Pollution↗
PubMed1991

Lead-glazed ceramics as major determinants of blood lead levels in Mexican women.

The aim of this study was to determine the main contributors to blood lead levels in a population of women from middle to low socioeconomic status in the southwestern part of Mexico City. Within this area, the authors selected a random sample of 200 women. Age ranged from 21 to 57 years, with a mean of 36 years. Among 99 women who agreed to participate in this study, blood lead levels ranged from 1 to 52 micrograms/dL, with a mean of 10.6 micrograms/dL. Five percent of the women had a blood lead level over 25 micrograms/dL and 22% over 15 micrograms/dL. There was no significant trend in blood levels according to age. The main determinants of blood lead levels were higher socioeconomic status (presence of telephone in the house, t-test, p = 0.01) and using lead-glazed ceramics (LGC) to prepare food (t-test, p less than 0.005). There was a significant increasing trend in blood lead levels with increasing frequency of consumption of food prepared in LGC (test for trend, p = 0.0008). Among the dishes prepared in LGC, the main determinant was the consumption of stew. Time spent outdoors and consumption of tap water and of canned food were not important determinants of blood lead levels. The population attributable risk of high blood level (less than 15 micrograms/dL) due to the use of LGC was 58%. These findings demonstrate the major role of traditional pottery as a contributor to blood lead levels in this population and emphasize the need for interventions to produce lead-free pottery.

Adult↗
PubMed1998

Predicting blood lead concentrations from lead in environmental media.

Policy statements providing health and environmental criteria for blood lead (PbB) often give recommendations on an acceptable distribution of PbB concentrations. Such statements may recommend distributions of PbB concentrations including an upper range (e.g., maximum and/or 90th percentile values) and central tendency (e.g., mean and/or 50th percentile) of the PbB distribution. Two major, and fundamentally dissimilar, methods to predict the distribution of PbB are currently in use: statistical analyses of epidemiologic data, and application of biokinetic models to environmental lead measurements to predict PbB. Although biokinetic models may include a parameter to predict contribution of lead from bone (PbBone), contemporary data based on chemical analyses of pediatric bone samples are rare. Dramatic decreases in environmental lead exposures over the past 15 years make questionable use of earlier data on PbBone concentrations to estimate a contribution of lead from bone; often used by physiologic modelers to predict PbB. X-ray fluorescent techniques estimating PbBone typically have an instrument-based quantitation limit that is too high for use with many young children. While these quantitation limits have improved during the late 1990s, PbBone estimates using an epidemiologic approach to describing these limits for general populations of children may generate values lower than the instrument's quantitation limit. Additional problems that occur if predicting PbB from environmental lead by biokinetic modeling include a) uncertainty regarding the fractional lead absorption by young children; b) questions of bioavailability of specific environmental sources of lead; and c) variability in fractional absorption values over a range of exposures. Additional sources of variability in lead exposures that affect predictions of PbB from models include differences in the prevalence of such child behaviors as intensity of hand-to-mouth activity and pica. In contrast with these sources of uncertainty and variability affecting physiologic modeling of PbB distributions, epidemiologic data reporting PbB values obtained by chemical analyses of blood samples avoid these problems but raise other issues about the validity of the representation of the subsample for the overall population of concern. State and local health department screening programs and/or medical evaluation of individual children provide PbB data that contribute to databases describing the impact of environmental sources on PbB. Overall, application of epidemiologic models involves fewer uncertainties and more readily reflects variability in PbB than does current state-of-the-art biokinetic modeling.

Animals↗
PubMed2003

[Blood lead levels in children and environmental legacy of a lead foundry in Brazil].

OBJECTIVE: To determine the blood lead levels in children living near an inactive lead foundry in the city of Santo Amaro da Purificação, state of Bahia, in September of 1998; and to identify factors associated with differences in these levels. METHODS: Cross-sectional study with children between 1 and 4 years of age living within 1 km of the lead foundry. Mothers or guardians of 47 children answered a questionnaire concerning ingestion of clay, soil, plaster and/or other materials (pica), and other relevant epidemiological aspects. The concentration of lead in blood was determined by atomic absorption espectrophotometry. RESULTS: The mean blood lead level was 17.1 +/- 7.3 micro g/dL. Blood lead levels were approximately 5 micro g/dl greater among children with pica, regardless of age, visible presence of scum surrounding the home, employment status of the father, family history of lead poisoning, and malnutrition. CONCLUSIONS: The environmental legacy of the lead foundry, which was shut down in 1993, continues to represent a relevant risk factor for increased blood lead levels in children, especially those presenting pica.

Brazil↗
PubMed1990

No adverse effects of lead on renal function in lead-exposed workers.

A cross-sectional study was performed on 165 male lead-exposed workers to clarify the quantitative relationships between less severe exposure to lead and its effects on renal function in 1985. Mean and range of blood lead concentration (Pb-B) were 36.5 micrograms/dl and 6-73 micrograms/dl, respectively. Duration of lead exposure was 0.1 to 26.3 years. No lead-related changes were detected in serum creatinine concentration, beta-2 microglobulin in urine, creatinine clearance, beta-2 microglobulin clearance, and uric acid clearance. Twenty of the 165 workers had been exposed to lead for more than 10 years with mean duration of 21.0 years. Average concentrations of Pb-B in each individual during 1972 to 1984 were 26.1-66.6 micrograms/dl. Renal function indices of these 20 workers were not different from those of remaining lead-exposed workers whose lead exposure duration were 10 years or less. These results suggest that long-term less severe exposure to lead up to 70 micrograms/dl of Pb-B may not cause adverse effects on renal glomerular function and proximal tubular function.

Adult↗
PubMed1999

Occupational exposure to lead--granulometric distribution of airborne lead in relation to risk assessment.

The amount of airborne lead absorbed by the body during occupational exposure depends not only on lead concentration in workplace air, but also on the granulometric distribution of the aerosol. The Occupational Safety and Health Administration (OSHA) set the lead Permissible Exposure Limit (PEL) at 50 micrograms/m3 on the basis of Bernard's model and a number of assumptions, including assumption "C", which predicts that the first 12.5 micrograms/m3 are made up of fine particles (aerodynamic diameter < 1 micron) whereas the remaining 12.5 micrograms/m3 consist of particles > 1 micron. Occupational exposure to airborne lead at a concentration of 50 micrograms/m3 and a granulometric distribution calculated according to the above mentioned assumption, leads, in the model, to a mean blood level of 40 micrograms/dl. In the present study, we tested the validity of assumption "C" in the environmental air of a factory that manufactured crystal glassware containing 24% lead oxide. An 8-stage impactor was used to measure the particle size of airborne dust collected from personal and area samplings. Results indicate that, on the whole, assumption "C" cannot be considered valid in the work environment investigated in this study. As a result, lead absorption levels in exposed workers may be noticeably different from those predicted by the OSHA model. We therefore suggest that in order to make a correct evaluation of the risk of occupational exposure to lead, it is essential to integrate total airborne lead concentration with a measurement of the granulometric distribution of the aerosol.

Aerosols↗
PubMed1992

Community prevalence survey of children's blood lead levels and environmental lead contamination in inner Sydney.

OBJECTIVE: To determine the distribution of blood lead levels in preschool children in inner Sydney and identify possible sources of environmental lead. DESIGN: Cross sectional community based prevalence survey of children and the houses in which they live, and a survey of volunteer children. SETTING: Mort Bay and Summer Hill, residential localities in inner Sydney. PARTICIPANTS: Ninety-five children aged 9-48 months able to be identified in a defined geographic area and 63 children aged 9-48 months volunteered by their parents. OUTCOME MEASURES: Concentrations of lead in venous blood of all children and in samples from the home environment of Mort Bay children. RESULTS: Four of the children (2.5%) had blood lead levels > or = 1.21 mumol/L (25 micrograms/dL, the current Australian threshold of concern), 27 (17.1%) had levels > or = 0.72 mumol/L (15 micrograms/dL, the new US threshold for individual intervention) and 80 (50.6%) had levels > or = 0.48 mumol/L (10 micrograms/dL, the new US threshold for community intervention). Blood lead concentrations were significantly correlated with concentrations of lead in "sink" soil (r = 0.555, P = 0.026), play area soil (r = 0.492, P = 0.016) and dust from vacuum cleaners (r = 0.428, P = 0.05), and with age of child (r = -0.182, P = 0.023). The presence of the child during house renovation was a strong predictor of having a blood lead level above 0.72 mumol/L (15 micrograms/dL) (odds ratio, 4.6; 95% confidence interval, 1.8-11.7, P = 0.001). CONCLUSIONS: Lead in soil and in household dust in older areas of Sydney is likely to represent a significant health hazard to young children. Many thousands of children may be affected in Sydney and other Australian cities. There is an urgent need for expanded prevalence surveys, public education and the development of strategies for the abatement of lead in urban environments.

Child, Preschool↗
PubMed2001

[Relationship between delta-aminolevulinic acid dehydratase gene polymorphism and blood levels of lead and zinc protoporphyrin in children exposed to lead].

OBJECTIVE: To explore the associations of polymorphism of delta-aminolevulinic acid dehydratase (ALAD) gene with blood levels of lead and zinc protoporphyrin (ZPP). METHODS: Blood samples were collected from 370 children exposed to a higher level environmental lead and their blood levels of lead and ZPP, and ALAD genotype were examined. Exposure to lead condition, such as parents' lead exposure and sites of lead source around their residence, and age and sex were matched in ALAD1-1 and ALAD1-2/2-2 subgroups. RESULTS: Blood lead level was higher in the ALAD1-2/2-2 subgroup than that in the ALAD1-1 children [(2.621 +/- 0.561) mumol/L vs (2.360 +/- 0.596) mumol/L, P = 0.04)]. Blood ZPP level was also higher in with ALAD1-2/2-2 subgroup than that in the ALAD1-1 genotype [(13.07 +/- 9.38) mumol/L vs (9.90 +/- 6.30) mumol/L), P = 0.02)]. CONCLUSION: The results suggest that the ALAD1-2/2-2 genotype may influence the body burden and blood toxicity of lead in high lead exposed children.

Child↗
PubMed2002

The distribution of blood lead levels and job titles among lead-acid battery workers in Taiwan.

There were several reports about elevated blood lead levels in lead battery workers. However, their subjects came from only one or several plants. We visited all the 23 registered lead-acid battery plants in Taiwan and collected their health examination records in 1992, the blood lead analyses of which were completed in 3 medical college hospitals. In total, we have obtained 1726 records. The average blood lead concentration was 37.1 ug/dl, and 37% of blood lead levels were more than 40 ug/dl (action level). The overall participation rate for health examination among employees was 69.4%. The participation rates were different among both plant sizes and job titles. Assuming that there was no peculiar variation within the four working zones (plate manufacture jobs, assembly jobs, part-time exposure jobs, and office jobs) in each plant, and that blood lead levels of our samples were stable after deleting newly hired workers, we estimated that the blood lead distributions of 2486 employees in these plants were 63.3%, 26.4%, 9.25% and 1.05% for below 40, 40-59, 60-79, and above 80 ug/dl respectively. We conclude that such an analysis should be performed each year to monitor the effectiveness of occupational hygiene in workplace of lead battery plants.

Humans↗
PubMed1992

Sampling of cortical and trabecular bone for lead analysis: method development in a study of lead mobilization during pregnancy.

The paper describes a methodological approach to the investigation of maternal-fetal transfer of lead in a non-human primate species, with particular focus on skeletal tissue, which is known to be a site of lead deposition. Eight female cynomolgus monkeys were dosed with lead acetate during gestation, and in four of the animals, the isotopic composition of the lead was modified by enriching the amount of the stable isotope 204Pb included in the dose. Biopsy and dissection procedures for the preparation of bone samples for lead analysis and stable lead isotope analysis are described. Emphasis is placed on the containment of potential contamination of the samples by lead during preparation. Containment procedures included: use of a Class 100 clean room, special cleaning regimes and use of Teflon containers and stainless steel instruments. Preliminary data of lead concentrations in adult bone (trabecular and cortical) and fetal bone subsequent to the dosing regimen of lead during pregnancy, suggest notable differences between the two bone "compartments" examined. The bone samples of fetuses from the dams which had received enriched 204Pb showed drastically reduced 206Pb/204Pb isotope ratios.

Animals↗