Blood Lead Levels In Workers Research Articles

Effects of occupational lead exposure on the indicators of immune function of workers

Objective: To investigatethe effects of different blood lead levels on indicators of immune function in occupationally lead-exposed populations. Methods: From October to December 2023, a total of 126 occupationally exposed lead workers of a company in Guizhou Province were selected, and their basic information was collected through questionnaires. Inductively coupled plasma mass spectrometry was used to detect blood lead levels in the study population. Workers were categorized into Group 1, Group 2 and Group 3 based on blood lead levels (blood lead levels <200 μg/L, 200~400 μg/L and >400 μg/L). Lymphocyte subpopulation marker leukocyte differentiation antigen (CD) in peripheral blood and interleukin (IL) -1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-17, tumor necrosis factor-alpha (TNF-α), and interferon (IFN) -γ in serum were examined by flow cytometry. Serum levels of immunoglobulin (Ig) A, IgG, IgM, and complement proteins (C3, C4) were measured by immunoscattering turbidimetry. Data were statistically analyzed using rank sum test, Chi-square test or Fisher exact probability method for multiple samples. Results: Compared with group 1, the percentage of CD3(+)CD8(+) and CD4(+)CD25(+) cells decreased (P<0.05) and the percentage of CD4(+) CD95(+) cells increased in the lead-exposed populations in groups 2 and 3 (P<0.05) ; however, the serum IL-1β, IL-2, IL- 5, IL-8, IL-12p70, and IFN-γ levels were decreased (P<0.05) in group 3. Meanwhile, IgG (P<0.05) and IgM levels in serum of lead-exposed population in group 2 and group 3 were reduced (P<0.05) comparing with group 1. Spearman correlation analysis showed that blood lead levels of workers were negatively correlated with the percentage of peripheral blood CD8(+)CD95(+) cells, CD3(+)CD8(+) cells, CD3(-)CD16(+) CD56(+) cells, IgG, IgM, and IgA (r(s)=-0.20, -0.22, -0.23, -0.24, -0.26, -0.35, P<0.05), but was positively correlated with the level of CD3(+)CD4(+) cells (r(s)= 0.18, P<0.05). Regression analysis revealed that blood lead level was a risk factor for the percentage of CD8(+)CD95(+) cells, CD3(+)CD8(+) cells, CD3(-)CD16(+) CD56(+) cells, IgG, IgM, and IgA (P<0.05) . Conclusion: Different lead loads can lead to abnormal changes in peripheral blood lymphocyte subsets, cytokines, and immunoglobulin levels in occupationally lead-exposed people. Lead exposure in occupationally lead-exposed populations may affect their immune function.

Analysis of blood lead level and its clinical significance among occupational exposed painters in chennai based population: A cross sectional study

Introduction and aimLead is a ubiquitous element found in the earth crust. There is no known physiologic role of lead in human body and hence any amount of lead present in human tissue considered as a contamination. Several studies on lead toxicity show that, occupational exposure remains the main source for lead toxicity and is emerging as important public health problem. Burden and severity of occupational exposure of lead and its clinical significance are gaining more interest in the field of toxicology. Only limited studies are available and there is scarcity of epidemiology data to assess the blood lead levels of workers and the contribution of common workplace practices to lead exposure in India especially from our region. So, the current study is designed to assess the blood lead levels (BLL) and its clinical significance among high risk workers especially painters working in the construction and public private sector in Chennai based population. Materials and methodsThis cross-sectional case control study included 122 painters and 122 healthy individuals. A detailed questionnaire about demographic details, personal habits, work related safety precautions, presenting symptoms of lead toxicity were given to painter followed by detailed medical examination and blood investigations including blood lead levels were collected and statistically analyzed. The t-test were used to compare mean blood lead levels and to investigate the associations between specific job type, use of self-protection device,sex, service years and occurrence of non-specific symptoms with BLLs. ResultsThe mean BLL of the painters were less than the recommended threshold level. Among painters 13.1% were categorized under BLL > 10 μg/dL. The higher BLL among the painters were directly proportional to year of experience and poor usage of personal protective materials. The levels of Hb, HCT and eosinophil were much correlated with lead toxicity. A marginal significance were observed in some parameters especially urea and creatinine when compared with control. The Cognitive dysfunction, hypertension and renal dysfunction were also observed among the painters. ConclusionThe BLL in painters among our group were minimal compared to biological reference value. Duration of exposure and association of patient’s clinical features like cognitive dysfunction, hypertension and renal dysfunction conditions were observed and this should be carefully monitored and study on huge population of painters with longitudinal aspect is recommended to rule out the clinical correlation of lead toxicity.

Food safety policy enforcement and associated actions reduce lead chromate adulteration in turmeric across Bangladesh

Turmeric adulterated with lead chromate pigment has been previously identified as a primary source of lead exposure in Bangladesh. This study assesses the impact of a multi-faceted intervention between 2017 and 2021 to reduce lead-tainted turmeric in Bangladesh. The intervention involved: i) disseminating findings from scientific studies via news media that identified turmeric as a source of lead poisoning, ii) educating consumers and businesspeople about the risks of lead chromate in turmeric via public notices and face-to-face meetings, and iii) collaborating with the Bangladesh Food Safety Authority to utilize a rapid lead detection technology to enforce policy disallowing turmeric adulteration. Before and after the intervention, evidence of lead chromate turmeric adulteration was assessed at the nation's largest turmeric wholesale market and at turmeric polishing mills across the country. Blood lead levels of workers at two mills were also assessed. Forty-seven interviews were conducted with consumers, businesspeople, and government officials to assess changes in supply, demand, and regulatory capacity. The proportion of market turmeric samples containing detectable lead decreased from 47% pre-intervention in 2019 to 0% in 2021 (n = 631, p < 0.0001). The proportion of mills with direct evidence of lead chromate adulteration (pigment on-site) decreased from 30% pre-intervention in 2017 to 0% in 2021 (n = 33, p < 0.0001). Blood lead levels dropped a median of 30% (IQR: 21–43%), while the 90th percentile dropped 49% from 18.2 μg/dL to 9.2 μg/dL 16 months after the intervention (n = 15, p = 0.033). Media attention, credible information, rapid lead detection tools and swift government action to enforce penalties all contributed to the intervention's success. Subsequent efforts should evaluate if this is an example of an effective intervention that can be replicated to reduce lead chromate adulteration of spices globally.

"Blood lead level among battery factory workers in low and middle-income countries: Systematic review and meta-analysis".

IntroductionLead is one of the most health-hazardous causes of acute and chronic poisoning at workplaces. A limited study was conducted on the blood lead concentration among battery factory workers in low and middle-income countries. Therefore, this study will improve workplace health and safety conditions of workers in this sector and serve as baseline data for further studies in this segment of the working setup.ObjectiveThis review aims to identify the pooled mean blood lead level among battery factory workers in low and middle-income countries.MethodsThe search methods considered the following electronic bibliographic databases: google scholar, PubMed, and other gray literature. A funnel plot and Begg test were used to see the publication bias. The heterogeneity of studies was checked using I-square statistics with a cut of point 75% and the Joanna Briggs Institute (JBI) quality assessment tool was applied to ensure the quality of the included articles. A random-effect model was applied to pool the blood lead level intoxication. The sub-group analysis and Meta-regression analysis were conducted by country and year of publication to control heterogeneity and to show variation. We included the articles published from 2000 to 2021 year in the English language.ResultsThrough the search strategies, 135 articles were identified and 43 full-text articles were selected for evaluation, and finally, eighteen (18) articles fit the inclusion criteria. From the 18 studies included in the meta-analysis, the mean pooled blood lead level of workers was 37.996 μg/dl (95% CI: 30.680–45.312) which is higher than the threshold limit value set by American conference of governmental industrial hygienists (20 μg/dl). In subgroup analysis by year in the random effect model, the pooled mean of blood lead level from 2006 to 2011= 43.20 μg/dL (35.91–50.50), 2012–2015 = 37.78 μg/dl (25.23–50.29), and 2016–2020 = 36.53 μg/dl (19.44–53.62).ConclusionsThis review showed that the pooled mean blood lead level of workers exposed to lead battery factories was (37.996 μg/dl) which is above the threshold limit value (20 μg/dl). Therefore, attention should be given by employers, government, and researchers to improve the health of working populations exposed to lead exposure in low and middle-income countries through the provision of occupational health and safety services like periodical medical checkups, treatments, and provision of training and adequate and appropriate personal protective equipment.Systematic review registration: Identifier: CRD42022322827.

Probabilistic pharmacokinetic modeling of airborne lead corresponding to toxicologically relevant blood lead levels in workers

The Department of Defense (DOD) commissioned the National Research Council (NRC) to assess the potential health effects associated with exposure of DOD personnel to lead (Pb) at firing ranges. In that report, NRC concluded that the current Occupational Safety and Health Administration permissible exposure limit and the blood lead levels (BLLs) on which it was based were not sufficiently protective of worker populations covered under the general industry standard. In support of future selection of an occupational exposure limit, the relationship of airborne Pb levels to BLLs is of interest to the DOD. A subset of the BLLs identified as relevant to the management of health risks of exposed workers was selected as targets for extrapolation to equivalent airborne Pb values. The existing O'Flaherty physiologically based pharmacokinetic model for Pb in humans was modified to facilitate probabilistic predictions of DOD worker population BLLs, including 95th percentile values, based on current worker characteristics. Workplace airborne Pb 8-h time-weighted average concentrations of 1.1, 4.0, 6.8, or 9.8 μg/m3 are anticipated to maintain BLLs below 5, 10, 15, or 20 μg/dl, respectively, in the vast majority of DOD workers exposed to Pb under full-time working lifetime occupational exposure.

Assessment of lead exposure controls on bridge painting projects using worker blood lead levels

A retrospective analysis of worker blood lead levels (BLL) was conducted using blood lead data collected by four bridge painting contractors before and after lead exposure. The objective of the study was to evaluate the effectiveness of exposure controls in preventing elevated blood lead levels (>25 μg/dl) during bridge painting projects. The contractors selected for the study submitted BLL data for 289 workers representing ten work tasks and 11 bridge painting projects. In total, 713 blood lead levels results were evaluated.The mean blood lead level for all work classifications combined was 10.9 μg/dl at baseline compared with 14.9 μg/dl after two months of exposure and 15.0 μg/dl after four months of exposure. Two months after initial exposure, 29% of the painters and 35% of the laborers had a 10 μg/dl incremental increase or greater in blood lead level. Likewise, 18% of the painters and 26% of the laborers had a blood lead level greater than 25 μg/dl during the same time. The blood lead levels that exceeded the 25 μg/dL threshold ranged from 30μg/dL-63 μg/dL for painters and 26 μg–56 μg/dL for laborers.All work tasks with high-intensity exposure (abrasive blaster/painter, abrasive blaster, painter & laborer) experienced an average blood lead level increase that ranged from 0.2 μg/dl to 8.9 μg/dl two months after initial exposure. Blood lead testing conducted after modified exposure controls (two months after the initial follow-up blood testing) were implemented showed a decrease in average blood lead levels (range −0.14 μg/dl to −2.7 μg/dl) for two high-intensity exposure work tasks. In comparison, the other two high-intensity work tasks had moderate increases (range 1 μg/dl to 2.4 μg/dl). The modified exposure controls included an increase in the air velocity inside of the work containment and an administrative control in the form of additional worker training on lead exposure prevention. The reduction in the 95th percentile (point estimate) BLL exposure profile for each exposure group at the 4-month follow-up blood testing period is associated with modified exposure controls.Ineffective exposure controls were identified through the analysis of worker BLLs. We found two exposure groups (laborer and painter) whose 95th percentile (point estimate) exposure profile was greater than the OSHA construction lead standard's targeted BLL goal (25 μg/dl) during the first two months of exposure. Our research findings provide support for monthly blood lead testing after baseline until blood lead levels are controlled to an acceptable concentration.

PIG-A gene mutation as a genotoxicity biomarker in human population studies: An investigation in lead-exposed workers.

The rodent Pig-a gene mutation assay has demonstrated remarkable sensitivity in identifying in vivo mutagens, while much less is known about the value of the human PIG-A assay for risk assessment. To obtain more evidence of its potential as a predictive biomarker for carcinogen exposure, we investigated PIG-A mutant frequencies (MFs), along with performing the Comet assay and micronucleus (MN) test, in 267 workers occupationally exposed to lead. Multivariate Poisson regression showed that total red blood cell PIG-A MFs were significantly higher in lead-exposed workers (10.90 ± 10.7 × 10-6 ) than in a general population that we studied previously (5.25 ± 3.6 × 10-6 ) (p < .0001). In contrast, there was no increase in lymphocyte MN frequency or in DNA damage as measured by percentage comet tail intensity in whole blood cells. Current year worker blood lead levels (BLL), an exposure biomarker, were elevated (232.6 ± 104.6 μg/L, median: 225.4 μg/L); a cumulative blood lead index (CBLI) also was calculated based on a combination of current and historical worker BLL data. Chi-square testing indicated that PIG-A MFs were significantly related to CBLI (p = .0249), but independent of current year BLL (p = .4276). However, % comet tail intensity and MN frequencies were better associated with current year BLL than CBLI. This study indicates that the PIG-A assay could serve as biomarker to detect the genotoxic effects of lead exposure and demonstrates that a battery of genotoxicity biomarkers having mechanistic complementarity may be useful for comprehensively monitoring human carcinogenic risk.

Evaluation of the Effectiveness of Hygenall&amp;lt;sup&amp;gt;&amp;amp;#169;&amp;lt;/sup&amp;gt; Leadoff&amp;lt;sup&amp;gt;TM&amp;lt;/sup&amp;gt; Foaming Soap in Reducing Lead on Workers’ Hands and the Uptake of Lead on Bridge Painting Projects

Although considerable research has been conducted regarding airborne lead exposures during lead paint removal, little data has been collected measuring the lead concentration on workers’ hands in the construction industry. As a result, there are gaps in our understanding of the effectiveness of a standard work practice control (handwashing) in the prevention and control of elevated blood lead levels (BLLs) in the workplace. The primary objective of this study was to assess if a National Institute for Occupational Safety and Health (NIOSH) formulation intended to remove lead from skin (Hygenall© LeadoffTM Foaming Soap) is more effective than a commonly used soap in the industrial painting industry (Zep Cherry Bomb Soap) in reducing the concentration of lead on workers’ hands after exposure. A secondary aim was to assess if using LeadoffTM Foaming Soap during handwashing reduces worker uptake of lead on bridge painting projects. We evaluated hand wipe, air sample and blood lead level data collected by two industrial bridge painting contractors. Airborne exposures ranged from 350 μg/m3 to 19,700 μg/m3. The geometric mean lead concentration remaining on workers’ hands after using Zep Cherry Bomb Soap was 77 μg per hand wipe compared with 61 μg per hand wipe after use of LeadoffTM Foaming Soap for all work classifications. The geometric lead concentration on workers’ hands decreased by 16 μg/hand wipe for all work classifications combined after using LeadoffTM Foaming Soap—a decrease of 21%. The use of Hygenall LeadoffTM Foaming Soap reduced the maximum lead concentration on workers’ hands by 85%. The geometric mean BLL for all work classifications was 12.1 μg/dl before the use of LeadoffTM. After two months of airborne exposure and use of LeadoffTM Foaming Soap at breaks and at the end of the workday, the geometric mean BLL for all work classifications increased to 18.1 μg/dl. Worker BLLs increased despite the reduction in the concentration of lead measured on workers’ hands—most likely a result of ineffective inhalation exposure controls. We found that the LeadoffTM Foaming Soap was more effective in removing lead from workers’ hands than Zep Cherry Bomb.

Blood Lead Level of Workers in a Printing Industry

Background: Different chemical materials especially inks are used in printing industry and lead is one of the ingredients that make up its pigments. Therefore, the objectives of present study were to examine blood lead levels and determine the correlation between hygiene behaviors and blood lead levels among workers in one of the printing industry located in the west of Tehran province. Methods: In this cross-sectional study that conducted in 2018, 80 workers of a printing house were selected. Blood samples were collected according NIOSH 8003 method and analyzed using a graphite furnace atomic absorption spectrophotometer GF 5000 model. Data were analyzed by Mann-Whitney, Kruskal-Wallis and Spearman correlation test using SPSS 20. The significance level of 0.05 considered for results. Results: The range of blood lead levels was 0.0094 to 0.1968 ppb. Individuals who worked in printing patterns process on cardboard sheets had blood lead levels higher than those working in other processes in this printing house (P &lt; 0.001). The workers who did not use masks (P = 0.034) and gloves (P &lt; 0.001) had higher mean lead atomic absorption than the others. Conclusion: The lack of using personal protective equipment could potentially increase the blood lead levels in printing industry workers.

Serum neuron-specific enolase, biogenic amino-acids and neurobehavioral function in lead-exposed workers from lead-acid battery manufacturing process.

Background: The interaction between serum neuron-specific enolase (NSE), biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. Objective: To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin) levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs). Methods: In a cross-sectional study, we performed biochemical and neurobehavioral function tests on 146 workers exposed to lead from lead-acid battery manufacturing process. BLLs were assessed by an atomic absorption spectrophotometer. Serum NSE, dopamine and serotonin were measured by ELISA. Neurobehavioral functions were assessed by CDC-recommended tests—simple reaction time (SRT), symbol digit substitution test (SDST), and serial digit learning test (SDLT). Results: There was a significant correlation (r 0.199, p<0.05) between SDST and BLL. SDLT and SRT had also a significant positive correlation (r 0.238, p<0.01). NSE had a negative correlation (r –0.194, p<0.05) with serotonin level. Multiple linear regression analysis revealed that both SRT and SDST had positive significant associations with BLL. SRT also had a positive significant association with age. Conclusion: Serum NSE cannot be used as a marker for BLL. The only domain of neurobehavioral function tests that is affected by increased BLL in workers of lead-acid battery manufacturing process is that of the "attention and perception" (SDST).

Elevated blood lead levels among unskilled construction workers in Jimma, Ethiopia

BackgroundNo study has been carried out to assess the blood lead levels of workers or the contribution of common workplace practices to lead exposure in Ethiopia. This study was carried out to assess the blood lead levels of female and male laborers in the construction sector in Jimma town, Ethiopia.MethodA cross-sectional study on the blood lead levels of 45 construction workers was carried out in the town of Jimma. The t-test, analysis of variance, the Kruskal-Wallis, Mann–Whitney and odds ratio tests were used to compare mean blood lead levels and to investigate the associations between specific job type, use of self-protection device, sex, service years and occurrence of non-specific symptoms with BLLs.ResultsThe mean blood lead level of the exposed group (40.03 ± 10.41 μg/dL) was found to be significantly greater than that of the unexposed group (29.81 ± 10.21 μg/dL), p = 0.05. Among the exposed group female workers were found to have higher mean blood lead level (42.04 ± 4.11 μg/dL) than their male colleagues (33.99 ± 3.28 μg/dL). Laborers who were regularly using self-protection devices were found to have significantly lower blood lead levels than those who were not using.ConclusionThe blood lead levels of construction workers in Jimma town are considerably high with a range of 20.46 – 70.46 μg/dL and the workers are in danger of imminent lead toxicity. More endangered are female construction workers who are bearers of the future children of the country and the issue requires urgent attention.

Evaluation of the Airborne Particles Fraction Responsible for Adverse Health Effects

A new approach to evaluation of the fraction of airborne particles that is responsible for adverse health effects has been developed. In this approach a two-fraction concept for the adverse health effects is proposed. This concept considers aerosol particles in the air, the fraction of particles deposited in the respiratory system (captured by the system) and the fraction of particle accumulated in the body (captured by the body). The latter fraction of airborne particles actually causes the adverse health effects and associated with the health risk. The approach has been applied to workers in crystal glass industry exposed to lead. A size resolved sampling technique was employed to characterize nanoparticles at work places at several plants involved in lead processing. Lead aerosol size distributions were obtained across the entire aerosol particle size range from 1 nm to 30 μm (diameter). Size distributions were used to calculate the total lead intake due to particle deposition in the respiratory system of workers. A bio-kinetic model was employed to evaluate various size fraction contributions to the total blood lead level in workers. A comparison was made between calculated blood lead levels and actual measurements of blood lead levels of workers exposed to atmospheres containing lead. It was found that nanoparticles cause the major health risk due to high deposition efficiency and low clearance rate by the mucociliary escalator.

What caused hemolytic anemia and colicky abdominal pain? Lead!

What caused hemolytic anemia and colicky abdominal pain? Lead!

Medical surveillance of blood lead levels in British workers

ObjectivesLead exposure and absorption can lead to many adverse health effects. Statutory monitoring of blood-lead levels in British workers has been undertaken since 1982 in order to prevent the occurrence...

자동차 정비업체 도장공정의 작업환경 및 근로자 노출 실태에 관한 연구

The purpose of this paper is to evaluate 1) blood lead levels of workers at auto repair shops as Biological Exposure Indices (BEI) of toxic substances such as lead and toluene that are produced during automotive painting process, 2) the differences depending on personal characteristics of workers who have been exposed to toluene by using urine hippuric acid concentration as a marker and 3) the correlation between the concentration of hazardous chemicals in each workplace and the BEL. All subjects were male with a mean age of 36.2 years. In terms of age, most were in the 30 to 40 age group (13 persons, 48.1%). In relation to the length of work experience, the highest proportion had experience of 10 years of less (18 persons, 66.7%). Twenty three workers were cigarette smokers (85.2%) while 4 (14.8%) were non-smokers. In addition, more than 80% of the workers drank alcohol. Dust concentration and toluene exposure during automotive painting showed no significant difference with age, length of work experience, smoking and drinking while a significant difference (p<0.05) has been detected between lead concentration and smoking. The geometric mean of dust concentration, lead concentration and toluene concentration were <TEX>$0.38mg/m^3,\;0.0021mg/m^3$</TEX> and 1.08ppm respectively. In addition, the geometric mean of blood lead levels and urine hippuric acid concentration were <TEX>$1.70{\mu}g/dl$</TEX> and 0.25g/g respectively, which were lower than the standard levels suggested by the Ministry of Labor. To determine the influential factors on blood lead and urine hippuric acid concentrations, a correlation analysis has been conducted with variables of air, lead and toluene concentrations, age, length of work experience and amount of cigarette smoking. According to the analysis, a relatively high correlation (p<0.01) has been observed between air lead concentration and biological sample concentration.

Occupational lead exposure effect on liver functions and biochemical parameters

The effect of occupational lead exposure on the liver function and on the blood biochemical parameters among the battery workers and the muffler repair workers was studied. The study included 22 battery and 38 muffler repair workers. Whole blood lead levels were determined by atomic absorption spectrophotometers. Total protein, albumin, globulin, cholesterol, triglyceride, total bilirubin, aspartate transaminase (AST), alanine transaminase (ALT), gamma glutamyltransferase (GGT), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) levels were determined in the serum by spectrophotometry. The blood lead levels of the battery workers, muffler repair workers, and the controls were found to be 36.83 +/- 8.13 microg/dL, 26.99 +/- 9.42 microg/dL, and 14.81 +/- 3.01 microg/dL, respectively. Blood lead levels of the workers were significantly higher than those of controls (p < 0.001). The lead level of the battery workers was also significantly higher than that of muffler repair workers (p < 0.001). Although, statisticly significant, higher blood lead levels are not related to toxicity for battery and muffler repair workers. Total protein, globulin, cholesterol, LDH, and ALP levels were within normal levels, however, they were slightly higher than the control levels. Increased LDH among the workers seems to be related rather to other causes than to the liver injury.

Effect of smoking on blood lead levels in workers and role of reactive oxygen species in lead-induced sperm chromatin DNA damage

To investigate whether cigarette smoking affects the blood lead levels (BLL) and whether exposure to lead introduces sperm chromatin DNA damage in factory workers. Cross-sectional study. A battery plant in Taiwan. Eighty male workers employed within a battery plant. Standard semen analysis was performed according to the World Health Organization guidelines. Assessment of BLL, sperm chromatin DNA structure, reactive oxygen species generation and other conventional parameters of semen quality. As compared with nonsmoking workers, the BLL were found to be considerably higher among smokers. Statistically significant differences were found in the sperm DNA denaturation (alphaT) induction and the percentage of sperm with increased DNA denaturation (COMP alphaT) in workers with moderate BLL (>or=25 microg/dL). After adjustment for smoking propensity, a positive correlation was discernible between BLL and alphaT, COMP alphaT, and morphologic abnormality. Furthermore, alphaT and COMP alphaT were also found to have positive correlations with sperm superoxide anion production. Workers with higher BLL were found to be at a higher risk of sperm morphologic abnormality and chromatin DNA integrity. These data are significant because they can facilitate the estimation of lead exposure in reproductive toxicology.

Exposure to Lead of Boatyard Workers in Southern Thailand

Lead oxide is used extensively in the construction and repair of wooden boats in Thailand, but the behaviors of boatyard workers that could place them at risk of contamination have not previously been documented. Baseline data on practices and behaviors of boatyard workers and on the level of worker and workplace contamination with lead were therefore collected. Fifty workers in two boatyards participated in this study. Lead exposure of workers was assessed by determining airborne and blood lead levels. A questionnaire was administered to collect information on work history, suspected exogenous lead sources, personal behavior and knowledge about lead. Evidence obtained by the study indicated that safety behavior and personal hygiene were poor--workers used no mask, gloves or hood, wore open sandals, smoked, drank, chewed and ate during work and did not wash their hands before drinking or eating. Some workers had lunch in the working area. The mean personal airborne lead of caulkers (36.4 microg/m3) was higher than that of carpenters (8.3 microg/m3). Forty-eight percent of all workers and 67% of caulkers had a blood lead level (BLL) exceeding 40 microg/dl. Multiple linear regression indicated that blood lead levels of workers were significantly related to job and education level, with significant differences between boatyards. In addition, the potential for "take-home" contamination was high; none of the workers took a shower or changed their clothes prior to going home. These results indicate a problem of lead exposure of sufficient magnitude to be a public health concern.

The decay of blood lead levels in workers suspended under the control of lead at work regulations

To study the rate of decline in blood lead levels post-suspension under Control of Lead at Work Regulations (CLAW) and thereby suggest sampling frequencies for follow-up blood lead measurements. A retrospective cohort of lead workers with blood lead levels over the current suspension level were identified from blood lead records. Data on their suspension and follow-up blood lead measurements were obtained. Sixteen per cent of the identified cohort did not appear to return to lead work under CLAW. Twenty-seven suspension cases with an initial mean blood lead of 79 microg/dl (3.82 micromol/l) formed the dataset for analysis of decline in blood lead levels. The mean length of time between the blood sample indicating suspension and the first follow-up blood sample was 32 days. The mean length of suspension under CLAW was 61 days. The mean initial rate of blood lead decay was 0.659 microg/dl per day (0.032 micromol/l per day), although with a wide range. The rate of decline in blood lead after suspension was increased by the blood lead level at suspension, but was decreased by increasing past cumulative exposure. A follow-up blood lead sample 1 month after suspension should show a mean decrease between 13 and 26 microg/dl (0.63-1.25 micromol/l), which is substantially greater than that due to analytical 'noise' associated with two sequential measurements (approximately 5 microg/dl). Therefore, a follow-up blood sample taken around 3-4 weeks after suspension would seem practical. A decrease in blood lead of 7-8 mug/dl (0.36 micromol/l) or less in the month after suspension may suggest continuing lead exposure.

Lead exposure and blood lead level of workers in a battery manufacturing plant in Thailand.

This study was conducted in a battery manufacturing plant where lead was used in the processes of production, to survey the working conditions and safety behaviors, and to measure the airborne lead level contaminated in the workplace and the blood lead level of workers. The survey of working conditions showed that the workers were directly exposed to lead in sections e.g. grid casting, spreading, forming and polishing, assembly and special battery production sections. Some workers in these sections used a cotton mask to protect dust exposure, but most workers did not use any masks. High airborne lead level more than 0.2 mg/m3 was frequently measured in these sections. Geometric average of blood lead level slightly increased from 17.9 microg/dl to 22.3 microg/dl during 1998 and 2001. However, the geometric average of blood lead level dropped to 17.4 microg/dl in 2002. No workers had blood lead level above 60 microg/dl. Workers with different age groups had no significantly different average blood lead level. Workers whose duration of work was between 20-29 years had average blood lead level of 21.5 microg/dl. This group of workers had slightly higher blood lead level than those whose duration of work was 19 years or less, but with no significant difference. 21 subjects underwent annual health examination and exposure monitoring in 2002. There was no significant relation between airborne lead level and blood lead level.