Evaluation of a portable blood lead analyzer with occupationally exposed populations

BACKGROUND: This project evaluated a portable electroanalytical instrument that is used to rapidly analyze blood lead levels in individuals, using a fresh whole blood sample (venous). METHODS: Samples were obtained from 208 lead-exposed employees who donated two 2 ml venous blood samples into "lead-free" evacuated tubes. One blood sample was analyzed onsite using the portable field instrument while the second sample was analyzed using graphite furnace atomic absorption spectrometry (GFAAS). RESULTS: According to GFAAS results, employee venous blood lead levels ranged from 1 microg/dl to 42 microg/dl. The mean difference between the results from the field instrument and GFAAS was less than 1 microg/dl. Analysis indicates that the results from the field instrument yielded a slight positive bias overall (P value = 0.0213), with less bias for blood lead levels above 10 microg/dl (P value = 0.0738). CONCLUSIONS: Within the blood range evaluated (1-42 microg/dl), the instrument performed adequately according to Clinical Laboratory Improvements Amendments (CLIA) proficiency requirements. The ability of the instrument to perform rapid analysis makes it potentially valuable to occupational health professionals for medical monitoring or on-site investigations.     

Field evaluation of a portable blood lead analyzer in workers living at a high altitude: a follow-up investigation

BACKGROUND: Field-portable instruments can offer expeditious analytical results to health professionals in field settings and in areas lacking laboratory infrastructure. This study further evaluated an electroanalytical field-portable instrument, which rapidly analyzes blood lead concentrations. METHODS: A portable anodic stripping voltammetry (ASV) instrument was evaluated utilizing paired samples from 243 employees working at an elevation of approximately 3,800 meters in Peru. Each worker donated two venous blood samples, one of which was analyzed by the ASV device and the other by a reference analytical method, graphite furnace atomic absorption spectrometry (GFAAS). RESULTS: According to the GFAAS results, the mean blood lead concentration measured was 46(+/-16) mug/dl; this was significantly greater than the mean ASV measurement of 32(+/-11) mug/dl (paired t-test; P < 0.0001). The accuracy of the ASV estimation decreased as the measured blood lead concentration increased. CONCLUSIONS: The results from this investigation were significantly different from the previous study, which was conducted near sea level. The exact causes for the discrepancies between the portable ASV results from the two studies are unclear, but are thought to be related to differences in blood chemistry between the Midwestern United States and Peruvian Andes worker cohorts. Portable ASV blood lead measurements from populations living at high altitudes should be viewed with caution. Am. J. Ind. Med. 46:656-662, 2004. Published 2004 Wiley-Liss, Inc.     

Take-home lead poisoning in a child from his father's occupational exposure

With the publication of revised CDC guidelines in 1991, concern about childhood lead poisoning has increased. Exposure to lead-based paint and paint dust is currently considered the major source of lead poisoning in the United States. We describe a child who had elevated BLL related to lead-contaminated clothing that the father brought home from his workplace. © 1996 Wiley-Liss, Inc.     

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.     

职业性慢性铅中毒患者血铅与血常规及网织红细胞参数相关性分析

目的 了解职业性慢性铅中毒患者血铅与血常规及网织红细胞参数的相关性,为职业性慢性铅中毒辅助诊断和疗效观察提供科学依据。
方法 选择117例职业性慢性铅中毒患者和住院排铅患者为研究组,选取同期来院健康体检的105名正常人为健康体检组,用全自动血细胞分析仪测定两组血常规及网织红细胞参数,分析血铅水平与这些指标的相关性。
结果 铅中毒组网织红细胞（RET）显著高于健康体检组、接铅正常组及铅吸收组（P < 0.05）;三个研究组弱荧光强度网织红细胞（LFR）均高于健康体检组,中荧光强度网织红细胞（MFR）、未成熟网织红细胞指数（IRF）、网织红细胞成熟指数（RMI）均低于健康体检组,差异均有统计学意义（P < 0.05）;铅中毒组强荧光强度网织红细胞（HFR）低于接铅正常组和铅吸收组（P < 0.05）。血铅水平与RET呈正相关（r=0.477,P < 0.01）,与血红蛋白（HGB）计数呈负相关（r=-0.203,P < 0.05）,与白细胞（WBC）计数呈负相关（r=-0.203,P < 0.05）,与血小板（PLT）呈负相关（r=-0.192,P < 0.05）。
结论 职业性慢性铅中毒对患者的血常规及网织红细胞参数存在一定影响,网织红细胞相关参数可作为铅中毒患者的早期辅助诊断指标。
     

铅暴露对某铅蓄电池企业719名作业工人血清生化指标的影响

目的 探讨铅暴露对作业工人血清生化指标的影响。
方法 选取武汉市某铅蓄电池企业719名现场铅作业人员作为调查对象,按《职业健康监护技术规范》的要求对其进行在岗期间职业健康体检,采用石墨炉原子吸收光谱法和自动生化分析仪分别测定研究对象血铅及血清生化指标,包括丙氨酸氨基转移酶（alanine aminotransferase,ALT）和门冬氨酸氨基转移酶（aspartate aminotransferase,AST）。以400 μg/L为界,将人群分为血铅水平≥ 400 μg/L的高血铅组和血铅水平 < 400 μg/L的低血铅组。采用多元线性回归模型分析719名铅作业人员的血铅与血清生化指标的相关性。
结果 低血铅组与高血铅组的血铅均值分别为（221.71 ±105.15）μg/L和（583.24 ±153.54）μg/L。血清ALT异常56名,异常率为7.79%;血清AST异常20名,异常率为2.78%。低血铅组ALT为（23.68 ±18.47）U/L,高血铅组ALT为（23.07 ±14.48）U/L;低血铅组AST为（21.88 ±10.18）U/L,高血铅组AST为（23.71 ±17.71）U/L;两组以上指标差异均无统计学意义（P>0.05）。多元线性回归结果显示:血铅每增加1 μg/L,工人血清AST升高0.004 U/L。
结论 血铅水平与血清AST值存在正相关关系,铅的蓄积可造成对肝脏组织的损害。
     

Evaluation of occupational exposure in a slide bearings factory on the basis of urine and blood sample analyses

The impact of a slide bearings factory on its workers was examined. Urine and blood samples were collected from 42 workers and six people employed in the offices in the same factory (control group). Concentrations of Al, Cu, Pb and Zn in blood and urine samples were measured twice (before and after chelation therapy) by ICP-MS technique using standard addition method. The essential differences in concentrations of elements for workers and control group were evaluated using non-parametric Mann-Whitney U-test. Significant differences between workers and control group were found for Pb in blood and Al in urine samples. The study was also undertaken to indicate correlation between blood and urine element content, workers' ages, their period of work and work section. It was also found that intravenous administration of 1 g of calcium-disodium versanate significantly increased urinary excretion of Pb and Zn, but not Al.     

A pilot evaluation of tibia lead concentrations in Taiwan

BACKGROUND: The aims of this study were to examine some of the factors that influence tibia lead concentrations, tibia lead x-ray fluorescence measurement uncertainty and blood lead concentrations, and to compare tibia lead concentrations in Taiwanese lead workers to those observed in lead workers from other countries. METHODS: A pilot evaluation of 43 adult lead workers who underwent measurements of tibia lead and blood lead concentrations. RESULTS: Mean and maximum tibia lead concentrations were 54 microg of Pb per g of bone mineral(microg/g) and 193 microg/g, respectively. Mean and maximum blood lead concentrations were 44 microg/dl and 92 microg/dl, respectively. CONCLUSION: Past occupational control of lead exposure in Taiwan, ROC, did not prevent these workers from accumulating tibia lead concentrations greater than those in similar workers elsewhere in the world.     

Occupational exposure to lead and blood pressure: a study in 105 workers

A group of workers, occupationally exposed to lead and cadmium compounds (n = 53), was compared to a group of workers not exposed to these metals (n = 52). The average values of systolic, diastolic, and mean blood pressure were found to be higher in the exposed group (p less than 0.05). In contrast with the correlation between CdU and blood pressure, the correlation between PbB and systolic and mean blood pressure remained statistically significant after controlling for age and pulse rate (r = 0.22, p less than 0.05). The prevalence of potential hypertension (defined as systolic blood pressure greater than or equal to 160 mm Hg and/or diastolic blood pressure greater than or equal to 95 mm Hg and/or under treatment for hypertension) was higher in the exposed group, but the observed relative risk was not statistically significant: relative risk = 1.91 (95% confidence limits, 0.90-4.05). Furthermore, a significant correlation between PbB and Hgb (r = -0.28, p = 0.004) was observed. Differences in kidney function, as assessed in this study, were not detected.     

The suitability of EBC-Pb as a new biomarker to assess occupational exposure to lead

Occupational exposure to lead (Pb) requires continuous surveillance to assure, as much as possible, safe and healthful working conditions. This study addresses the suitability of assessing Pb exposure in relevant workers using their exhaled breath condensate (EBC). This study enrolled workers of two different Pb processing industries characterized by moderate and high Pb exposure levels in the work environment, and a group of non-exposed individuals working in offices who served as baseline for Pb exposure. The EBC-Pb of workers reflected the Pb levels in the work environment of all three settings, although the relationship with B-Pb was not clear. The lack of correlation between EBC-Pb and B-Pb most probably indicates the time lag for Pb to enter in the two body pools. The EBC-Pb seems to reflect immediate exposure, providing a prompt signature of Pb in the environmental that may interact directly with the organ. By delivering short-term evaluation of exposure, EBC-Pb represents a clear advantage in biomonitoring and may become an interesting tool for estimating organ burden.     

Particle size distributions of lead measured in battery manufacturing and secondary smelter facilities and implications in setting workplace lead exposure limits

Inhalation plays an important role in exposures to lead in airborne particulate matter in occupational settings, and particle size determines where and how much of airborne lead is deposited in the respiratory tract and how much is subsequently absorbed into the body. Although some occupational airborne lead particle size data have been published, limited information is available reflecting current workplace conditions in the U.S. To address this data gap, the Battery Council International (BCI) conducted workplace monitoring studies at nine lead acid battery manufacturing facilities (BMFs) and five secondary smelter facilities (SSFs) across the U.S. This article presents the results of the BCI studies focusing on the particle size distributions calculated from Personal Marple Impactor sampling data and particle deposition estimates in each of the three major respiratory tract regions derived using the Multiple-Path Particle Dosimetry model. The BCI data showed the presence of predominantly larger-sized particles in the work environments evaluated, with average mass median aerodynamic diameters (MMADs) ranging from 21–32 µm for the three BMF job categories and from 15–25 µm for the five SSF job categories tested. The BCI data also indicated that the percentage of lead mass measured at the sampled facilities in the submicron range (i.e., <1 µm, a particle size range associated with enhanced absorption of associated lead) was generally small. The estimated average percentages of lead mass in the submicron range for the tested job categories ranged from 0.8–3.3% at the BMFs and from 0.44–6.1% at the SSFs. Variability was observed in the particle size distributions across job categories and facilities, and sensitivity analyses were conducted to explore this variability. The BCI results were compared with results reported in the scientific literature. Screening-level analyses were also conducted to explore the overall degree of lead absorption potentially associated with the observed particle size distributions and to identify key issues associated with applying such data to set occupational exposure limits for lead.     

Plasma-lead concentration: investigations into its usefulness for biological monitoring of occupational lead exposure

BACKGROUND: The lead concentration in plasma is correlated to that in whole blood with a two to fourfold variation. It has never been investigated if this variation is inter-individual. METHODS: Lead and hemoglobin were determined in blood and plasma from 13 lead workers with a history of relatively high blood-lead concentrations, sampled three times during 1 day. The variation in the distribution of lead between cells and plasma was studied, but not the variation in the lead concentrations as such. RESULTS: Blood hemoglobin decreased with rising plasma lead (0.9-3.0 microg/L). Regarding the distribution of lead, no effect of current exposure during the day or of recent meals appeared. As much as 84% of the overall variance of the distribution of lead between cells and plasma could be attributed to individual factors. After adjustment for erythrocyte volume fraction this decreased to 67%. Plasma samples with elevated hemoglobin concentrations (due to in vitro hemolysis) had somewhat elevated lead concentrations. CONCLUSIONS: Plasma lead is not significantly altered by variation in a single day's exposure and, therefore, the choice of time of the day is not critical for sampling. However, plasma lead is negatively correlated to blood hemoglobin and mild hemolysis (not visible by the eye) in a sample may increase plasma lead with up to 30%. Finally, plasma provides lead exposure information that differs from whole blood, but it is not clear which one of these is the biomarker with the closest relation to exposure and/or effects.     

Occupational lead exposure in Los Angeles County: an occupational risk surveillance strategy.

To better understand occupational lead exposures in Los Angeles County, we undertook a questionnaire survey of lead-using industrial facilities not previously identified by county health department staff. Previously our staff had identified 112 lead-using companies with approximately 2,000 lead-exposed workers countywide. For this survey, we developed a database of 1,353 possible lead-using industrial facilities from several sources, including community "right-to-know" databases, air pollution or sewer permit records, or other environmental databases. A questionnaire interview was completed with 1,001 (81%) of these companies, yielding 178 previously unidentified facilities employing 7,734 workers with potentially significant occupational lead exposures. Compliance with the OSHA lead standard was often poor in these facilities, particularly for workplaces with 20 or fewer employees. Devoting more public health resources to targeted identification of such industrial facilities and to educational outreach would likely help control occupational lead exposure.     

Effect of lead on blood pressure in occupationally nonexposed men

To determine if low-level exposure to lead has an effect on arterial blood pressure, demographic and clinical data of a group of 507 males without any occupational exposure to lead were analyzed in a retrospective study. The following variables were included in the analysis: age, height, weight, nicotine consumption, alcohol intake, blood lead, systolic blood pressure, diastolic blood pressure, and erythrocyte count. The effects of the variables age, weight, height, alcohol intake, nicotine consumption, and blood lead on blood pressure were investigated by stepwise linear regression analysis. The diastolic as well as the systolic blood pressure was significantly influenced by Body Mass Index, age, and alcohol. A significant effect of lead could be found only for diastolic blood pressure. None of the possible interactions were significant enough to merit inclusion in the statistical model. Regarding the strength of the effects on diastolic blood pressure we find that lead ranks after age, weight. In conclusion, this study shows that lead has an effect on diastolic arterial blood pressure in a survey of a group of middle-aged, occupationally nonexposed men.     

Partition of circulating lead between serum and red cells is different for internal and external sources of lead

Serum lead, whole blood lead, and lead in both tibia and calcaneus were measured in each of 49 active lead workers. Serum lead correlated more strongly with both in vivo bone lead measurements than did whole blood lead. The ratio of serum lead to whole blood lead varied from 0.8% to 2.5% and showed a positive correlation with tibia, and an even stronger correlation with calcaneus lead. This implies that lead released from bone (endogenous exposure) results in a higher proportion of whole blood lead being in serum than is the case for exogenous exposure. This observation needs to be confirmed, and the relationships amongst the parameters must be studied further, particularly in former or retired lead workers. If confirmed, since at least a portion of lead in serum is readily diffusible and thus toxicologically more immediately significant than lead bound to red cells, the health implications of endogenous exposure may have to be reassessed. © 1996 Wiley-Liss, Inc.