California adults with elevated blood lead levels, 1987 through 1990

Optimization of a GF-AAS method for lead testing in blood and urine: A useful tool in acute abdominal pain management in emergency

Suspicion of lead poisoning is confirmed by its concentration in blood and protoporphyrin red blood cells. At low concentrations, lead influences the synthesis of the heme in the sense of lowering it. Acute and chronic lead intoxication is extremely polymorphic in regards to its clinical manifestations, with digestive, hematological, cardiovascular, renal hepatic and neurological features. The aim of the study was to evaluate the presence of lead in human whole blood and urine harvested before and during chelation treatment in the case of lead poisoning. An atomic absorption spectroscopic method for the analysis of lead was developed using graphite furnace atomic absorption spectrophotometer (GF-AAS), Varian Spectra AA-880 with a hollow cathode lead lamp and a deuterium lamp for background correction, coupled to a GTA-100 atomizer and a programmable sample dispenser. Standard calibration solutions were used for the range 10-100 µg/l. The linearity range was 10.0 to 100.0 µg/l with the correlation coefficient of 0.999. We established that the method can be applied for the determination of lead in whole blood and urine, and the results obtained are useful for monitoring chelation therapy in cases of acute lead poisoning, a neglected cause of abdominal colic pain in an emergency situation.

Homeopathic Plumbum metallicum for lead poisoning: a randomized clinical trial

INTRODUCTION

Poisoning due to lead and its compounds has short and long-term effects primarily on the nervous, hematopoietic, gastrointestinal, cardiovascular, musculoskeletal, renal and reproductive systems. It can manifest in acute or chronic symptoms. Measuring serum concentration is the primary method for diagnosing and monitoring exposed workers. Presently, elevated lead levels are treated by drugs whose effectiveness is contested on various fronts. Experimental studies suggest that homeopathic preparations may be in controlling blood lead levels in laboratory animals, creating the need for controlled studies to evaluate the effectiveness and safety of these preparations in humans.

OBJECTIVE

To evaluate the effectiveness of the homeopathic preparation Plumbum metallicum in reducing the blood lead level of workers exposed to this metal.

DESIGN

Double-blind randomized trial.

SETTING

Workers' clinic in the Ajax battery plant, which employs 900 workers with varying degrees of lead exposure in Bauru, São Paulo State, Brazil.

SUBJECTS

131 workers exposed to lead.

INTERVENTION

Plumbum metallicum 15 cH or placebo, orally for 35 days.

RESULTS

The percentage of workers who demonstrated a reduction in lead counts by a percentage greater than or equal to 25% following treatment was the same for both groups: 20.3% in the homeopathic groups versus 21% in the control group [Relative Risk (RR) = 0.95, confidential interval (CI) 95%: 0.47-1.92)]. Analysis by intention-to-treat also did not show any difference between the groups: 18.2% in the treated group versus 20% in the placebo group (RR = 0.91, CI 95%: 0.45-1.84).

CONCLUSION

The homeopathic preparation Plumbum metallicum had no effect, in this study, in terms of reducing serum lead in workers exposed to lead.

Adult Blood Lead Reporting in New York State, 1994–2006

Objectives.

Laboratories that test New York State (NYS) employees and adult residents for lead exposure are required to report blood lead test results to the NYS Department of Healths Heavy Metals Registry. This registry is used to monitor exposures and to identify new high-risk occupational and nonoccupational activities.

Methods.

We used interviews conducted with people having blood lead levels of ≥25 micrograms/deciliter (μg/dL) reported to the Heavy Metals Registry to determine the primary source of lead exposure. We reviewed this information, together with demographic information, for the years 1994 through 2006.

Results.

While overall there has been an increase in the number of tests being conducted on NYS residents since 1994, the vast majority of the increase is among those with the lowest blood lead levels (<10 μg/dL). Conversely, there has been a decline in the number of adults tested with blood lead levels of ≥25 μg/dL in NYS due primarily to occupational exposures. However, nonoccupational exposures do represent a relatively large percentage of the individuals with severely elevated blood lead levels (≥60 μg/dL).

Conclusions.

Although a surveillance system based on blood lead levels cannot identify the true magnitude of adult lead poisoning, the NYS Heavy Metals Registry has proven to be an important tool for identifying situations in which adult lead poisoning is occurring, and assists in guiding lead poisoning prevention among adults.

Multiple risk factors for lead poisoning in Hispanic sub-populations: a review

As a result of recent media attention to lead (Pb) in consumer products, Pb exposure and toxicity to children has been placed back on the national agenda. This review presents the current literature on sources of Pb in Hispanic sub-populations in the broader context of national lead poisoning trends, sources, and exposure pathways. Pb poisoning among Hispanics is a multi-dimensional issue that is far more complex than for the general population in terms of environmental, cultural, and social dimensions. As a result, a higher percentage of Hispanic children have elevated blood lead levels compared to the general population. Given the additional risks that Hispanics face, all Hispanic children should be defined as "at risk" for lead exposure and included in targeted screening programs. This review concludes with specific public policy recommendations that directly address the increased risk of Pb poisoning to Hispanic children so that Pb will poison fewer children in the future.

Sick and tired of being sick and tired: scientific evidence, methods, and research implications for racial and ethnic disparities in occupational health

The extent of racial/ethnic disparities in occupational health have not been well studied. The author reviews the evidence about workers of color and occupational injuries and disease. Patterns of employment in the U.S. workforce according to education, gender, and race/ethnicity are discussed, and how these patterns might cause disproportionate exposure leading to disproportionate disease and injury. Methodological issues are explored that have hampered research about occupational health disparities, and future research needs are identified.

Blood lead levels among children of lead-exposed workers: A meta-analysis

BACKGROUND

To further assess the utility of targeted blood lead screening for children from households with members having occupational lead exposures, we conducted a meta-analysis of all available reports of take-home lead exposures. Our objective was to estimate the blood lead levels among U.S. children (ages 1-5) from households with lead-exposed workers.

METHODS

Reports considered for inclusion were cited in Medline, Toxline, Excerpta Medica, and Bio-Med plus all unpublished reports available at the National Institute for Occupational Safety and Health through 1994. The a priori criteria for inclusion of U.S. reports required their having data on: (1) venous blood lead levels for children, (2) children's ages, (3) data for at least five children, (4) workers' occupations, (5) workers' blood lead levels, and (6) data collection methods.

RESULTS

Based on a meta-analysis of 10 reports from 1987 through 1994, the children (n=139) of lead-exposed workers (n=222) had a geometric mean blood lead level of 9.3 microg/dL compared to a U.S. population geometric mean of 3.6 microg/dL (P=0.0006). Also in this group, 52% of the children had blood lead levels (BLLs) >/= 10 microg/dL compared to 8.9% in the U.S. (P=.0010), and 21% of the children had BLLs >/= 20 microg/dL compared to 1.1% in the U.S. (P=. 0258).

CONCLUSIONS

We estimate, based on 1981-83 survey data, that there are about 48,000 families with children under six living with household members occupationally exposed to lead. If the findings from this meta-analysis (admittedly limited by small numbers) are generalizable, about half of the young children in these families may have BLLs >/= 10 microg/dL. Data were too sparse to determine if children of workers with elevated blood leads were at greater risk than children whose parents were only known to be lead exposed. Our findings support the position that children of lead-exposed workers should be targeted for blood lead screening. Am. J. Ind. Med. 36:475-481, 1999. Published 1999 Wiley-Liss, Inc.

[Occupational lead exposure assessment: a proposal for a strategy to monitor prevention of clinical and subclinical effects]

In developing countries, lead-acid battery factories are one of the heaviest consumers of lead. Due to lead's toxicological properties and prevalent working conditions in such factories, workers are subject to high exposure and health risk. This study discusses results obtained by lead exposure assessment of workers from a Rio de Janeiro battery factory, in light of Brazilian legislation and recent scientific data. Evaluation methods used were environmental (personal air sampling) and biological (determination of lead in blood, Pb-B) monitoring, showing a high personal exposure both in air (>0.1 mg/m3) and blood (55% of Pb-B >25 microg/dl). These results confirmed the inefficiency of current control measures, with a possible 46% of workers presenting a Pb-B range of 25-60 microg/dl in risk areas. Recent data suggest that Pb-B levels above 25 microg/dl are related to subclinical alterations in human body that should be investigated during clinical examination. Finally, we propose a strategy based on environmental and biological monitoring to prevent both clinical and subclinical effects.

The acute effect of lead acetate on glucocorticoid receptor binding in C6 glioma cells

Lead exerts significant toxic effects on the nervous system, the hematopoietic system and the kidney. Specific cellular sites of action of this environmental pollutant have not been elucidated in the central nervous system. The present investigations were conducted to test the hypothesis that lead exposure perturbs glucocorticoid-mediated events in central nervous system hormonal target tissues. Utilizing the C6 glioma cell culture model in these studies, glucocorticoid receptor binding to its cytosolic receptor was investigated. Receptor binding studies yielded a Kd= 10.5 +/- 0.5 nM and a Bmax = 486 +/- 27 fmol/mg protein in untreated cells versus a Kd = 23.1 +/- 2.6 nM and Bmax = 472 +/- 35 fmol/mg protein in cells exposed to 10 microM lead acetate for 24 h. Presence of lead in these glial cells may decrease affinity of the glucocorticoid for its receptor without affecting receptor number. Treatment with 10 microM lead acetate for 48 h, resulted in a significant reduction in glucocorticoid-regulated glycerol phosphate dehydrogenase (GPDH) specific activity. These effects were not due to cell cytotoxicity assessed as cell number growth curves, [3H]thymidine incorporation or trypan blue exclusion. In protein kinase C (PKC) activity assays, treatment of cells with sodium or lead acetate and dexamethasone indicated that both lead and dexamethasone affect the distribution of PKC. In lead-treated cells cytosolic PKC activity was reduced 48% when compared to sodium acetate treated controls. Taken together, these results suggest that acute exposure of C6 cells to lead may inhibit processes involved in glucocorticoid-mediated signal transduction events within central nervous system hormonal target cells. Lead may perturb initial glucocorticoid binding events possibly by affecting PKC-mediated phosphorylations in the glucocorticoid signal transduction system.

The acute effect of lead acetate on glucocorticoid regulation of tyrosine aminotransferase in hepatoma cells

Specific cellular sites of action of the environmental pollutant, lead, have not been completely defined. The present investigations were conducted to test the hypothesis that lead exposure perturbs glucocorticoid-mediated effects in hormonal target tissues. The cell culture model chosen for these investigations was the effects of lead on glucocorticoid-regulated tyrosine aminotransferase (TAT) specific activity in the H4-II-C3 hepatoma cells. Cells were treated with 300 nM-10 microM lead acetate for 24 or 48 h in absence or presence of the inducing agent, dexamethasone. Lead dose-dependently inhibited TAT specific activity up to 52% and 61% following 24 and 48 h lead treatments, respectively. These treatment times and concentrations of lead acetate did not significantly alter total cell numbers, [3H]thymidine incorporation or trypan blue exclusion. Glucocorticoid receptor-binding studies yielded a Kd = 8.3 nM and a Bmax = 290 fmol/mg protein in untreated cells versus a Kd = 9.2 nM and Bmax = 262 fmol/mg protein in cells exposed to 10 microM lead acetate for 48 h. Treatment with lead did not significantly perturb uptake of the inducing glucocorticoids or initial cytosolic receptor-binding events. To sustain induced levels of TAT, glucocorticoid must be continuously present. Following steroid withdrawal, enzyme de-induction was significantly altered in lead-treated cells. At 6 h following dexamethasone withdrawal, TAT levels had decreased to 51% of maximum in sodium acetate-treated cells. This was significantly reduced to 33% of maximum in lead acetate-treated cells. Lead treatment of HTC cells was also shown to ameliorate PMA amplification of dexamethasone-induced TAT activity. Taken together, these results suggest that acute exposure of cells to lead may inhibit processes involved in glucocorticoid-mediated enzyme induction within the hormonal target cell. Results suggest that lead may be acting to increase the turnover of TAT by actions at the transcription, translation and/or posttranslational level. Lead may also be affecting PKC-mediated phosphorylations in the glucocorticoid-TAT signal transduction system.

Blood lead levels in North Carolina painters

1. Blood lead levels were examined in 127 housepainters in North Carolina between April and September, 1993. Each participant filled out a questionnaire and gave a blood sample. The questionnaire covered the individual's work history, concentrating on paint-removal activities and personal protection, and also covered potential nonoccupational sources of lead exposure. Blood samples were analysed for lead content using atomic absorption spectroscopy. 2. The geometric mean blood lead level was 0.33 mumol L-1 (6.8 micrograms dL-1). No blood lead samples were found to exceed the occupational standard of 1.93 mumol L-1 (40 micrograms dL-1). The three highest samples had levels between 0.97 and 1.45 mumol L-1 (20 and 30 micrograms dL-1); this represented 2.4% of the study sample. 3. No statistical association was found between blood lead levels in these painters and their painting activities, including using dust masks for personal protection. 4. Current painting practices in this group of North Carolina painters do not appear to elevate blood lead levels above the occupational standard.

Elevated blood lead levels among construction workers in the Massachusetts Occupational Lead Registry

Although the construction industry until recently was exempt from the Occupational Health and Safety Administration General Industry Lead Standard, including its medical monitoring provisions, periodic blood lead tests have been required for residential "deleaders" and structural painters in Massachusetts. Sixty-three percent of the 381 registrants in the Massachusetts Occupational Lead Registry with blood lead levels of 1.93 mumol/L or higher are construction workers. This proportion is much higher than that reported by registries of several states selected for comparison. These data highlight the need for better protection from lead exposure and the effectiveness of mandatory medical surveillance in identifying elevated blood lead levels among construction workers.

The initial impact of a workplace lead-poisoning prevention project

The California Department of Health Services began an occupational lead poisoning prevention project in cooperation with 275 radiator service companies. The agency developed and marketed resources to facilitate companies' own efforts, tracked the progress of each company, and urged the companies to conduct blood lead testing. Testing by participating employers increased from 9% to 95%, and 10 times as many companies with likely overexposures were identified as had been reported to the state's lead registry in the previous year. The success of this project indicates that the model should be applied more extensively.