Effects of occupational metallic mercury vapour exposure on suppressor-inducer (CD4+CD45RA+) T lymphocytes and CD57+CD16+ natural killer cells

Objectives: To examine the effects of metallic mercury vapour on the cellular and humoral immune system. Methods: We measured T lymphocyte and natural killer (NK) cell subpopulations, B lymphocytes, and serum immunoglobulins (i.e. IgG, IgA and IgM) together with total T (CD3+) lymphocytes and total lymphocytes in blood samples from 20 male, fluorescent-lamp makers (mercury workers) and the same number of gender-, age- and smoking-matched controls. Urinary concentrations of inorganic mercury (UHg) in the 20 workers ranged from 1.8 to 163.5 (mean 44.8) μg/l. They had been exposed to mercury vapour for 4 to 62 (mean 31) months. Results: Numbers of CD4+CD45RA+ (suppressor-inducer) T lymphocytes and total CD4+ T lymphocytes in the mercury workers were significantly smaller than those in the controls (paired-sample t-test, P < 0.01). The number of CD57+CD16+ NK cells was inversely correlated with UHg. Conclusion: It is suggested that numbers of CD4+CD45RA+ T lymphocytes and CD57+CD16+ NK cells are inversely affected by exposure to metallic mercury vapour in workers, with an average urinary inorganic mercury concentration of 45 μg/l being found. Received: 7 September 1999 / Accepted: 6 May 2000     

高温噪声暴露对钢铁冶金工人血脂的影响

目的 了解高温噪声接触对作业工作工作血脂的影响。方法 对某钢铁企业暴露于噪声和高温、单纯暴露噪声和对照组共1441名男性工人血脂进行测定。结果 高温噪声接触、单纯噪声接触组血清总胆固醇（TC）水平与对照组相比较有一定程度增高。同一累积噪声剂量水平,单纯噪声接触组血清甘油三酯（TG）高于高温噪声组。非条件logistic回归分析表明：在控制了年龄、体重因素后,累积噪声剂量是高TC血症的独立危险因素,而高温级别则可能是高TC血症的保护因素;多元线性回归模型分析显示：血清TC水平与累积噪声剂量呈正相关,与高温级别呈负相关。结论 长期噪声接触可能会导致血脂增高。     

The influence of workplace environment on lung function of flour mill workers in Jalgaon urban center

The workplace environment affects the health of workers. Unhygienic conditions are observed in the workplace environment of flour mills as fine organic flour dust gets airborne in the indoor environment of the flour mills. The present work was undertaken to study the health problems related to the workplace environment of flour mill workers. The results show that flour mill workers are receiving a heavy dose (average exposure concentration, 624 microg/m3) of flour dust. To determine the impact of flour dust on the lung function of the workers spirometric analysis was conducted. Significant declines in forced vital capacity (FVC), peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV1) were observed in the flour mill workers as compared to expected values. This study reveals reduced lung efficiency of flour mill workers due to excessive exposure to fine organic dust prevalent in the workplace environment. The impairment in lung efficiency was increased with duration of exposure in the flour mill workers. The analysis of questionnaires used to generate information on self-reported problems reveals that most of the workers were suffering from asthma and respiratory problems. Furthermore, the data shows that 42% of the flour mill workers were having shortness of breath problems, 34% of workers were having frequent coughing, and 19% workers were having respiratory tract irritation. We recommend the compulsory use of personal protective equipment (nose mask) by flour mill workers during working hours. This would help to protect the workers health from the flour dust prevalent in the workplace environment. A regular periodic examination is necessary to measure the impact of particulate matter on the health of the flour mill workers.     

Prevalence of respiratory symptoms and disorders among rice mill workers in India

Objectives

Lung function tests have become an integral part of assessment of pulmonary disease. Diseases of the respiratory system induced by occupational dusts are influenced by the duration of exposure. The aim of the study is to investigate the impairment of lung function and prevalence of respiratory symptoms among the rice mill workers.

Methods

A total of 120 rice mill workers from three districts of Karnataka were included in this study. Fifty urban dwellers from the same socio-economic level were selected as controls. The study included clinical examination, assessment of respiratory symptoms, pulmonary function test, measurement of peak expiratory flow rate, absolute eosinophil count, ESR estimation, total IgE estimation and radiographic test.

Results

The present study has shown that the rice mill workers complained of several types of respiratory disorders like phlegm (40.8 %), dyspnea (44.2 %), chest tightness (26.7 %), cough (21.7 %), and nose irritation (27.5 %). Rice mill workers exposed to dust presented significantly (p < 0.05) lower levels of FVC (3.44 ± 0.11), FEV₁ (2.73 ± 0.15) and PEFR (304.95 ± 28.79) than the controls. The rice mill workers are having significantly higher absolute eosinophil counts, total IgE and ESR than control groups. The hematological findings suggest that the harmful effects may be linked to both non-specific irritation and allergic responses to rice husk dust among rice mill workers.

Conclusion

Dust exposure in the working environment affects the lung function values and increased the respiratory symptoms among the rice mill workers.     

Immunization Against Poliomyelitis

The δ-aminolevulinic acid (ALA) dehydratase activity in erythrocytes, the cholinesterase (ChE) activity in serum, the urinary output of ALA, coproporphyrin, protein, and mercury, and the level of reduced glutathione (GSH) in erythrocytes were determined in mercury workers. A significant correlation (P < 0.01) was found between the urinary level of mercury and the values for the decreased activities of ALA dehydratase and ChE, and for the urinary level of coproporphyrin, though their values were not so prominent as in lead poisoning. It was concluded that the response of the biological system in vivo to the metals differs greatly from that in vitro, and that the maximum permissible urinary concentration of mercury would be 200μ g/gm creatinine.     

The Human Cost of Protecting the Environment: Waste Management and Health

Abstract

The majority of the population in Bangladesh is employed in manual handling tasks, but adequate protections for these workers do not exist. Conditions at a boulder handling site, saw mill, rice packaging plant and construction site show the need for comprehensive reforms in occupational safety and health legislation and practice in Bangladesh. New policies on training, industrial hygiene, safety equipment, and risk assessment are necessary to protect workers in a rapidly developing economy.     

Photic stimulation in early diagnosis of the effects of some harmful industrial substances on the central nervous system

Summary Response to photic stimulation was analyzed in the EEG records of 114 workers: 67 of them experienced long-term, intense exposure to CS₂; 27 of them were exposed to mercury, and 20 of them to trichloroethane and toluene. The results were compared with that of a control group of 20 people.The photic stimulation (P.S.) response by the 3 groups of exposed persons differed. In workers in the mercury-hazard environment the response was generally extended to low and high frequencies (63%). In workers in the CS₂ environment the response capability was reduced (40.3% of the cases investigated) or completely absent (41.8% of the cases studied). In the group of workers in the solvent-hazard environment 2 types of response occurred: either they showed low frequencies (35%) or had 2 culmination points — in the theta and beta bands (55%).It became clear that in persons exposed to mercury and solvents, a changed P.S. response is an early sign as it occurs in persons who show no clinical signs and in those with no changes in the native EEG record.Attempts were made to interpret the observed changes.It is concluded that photic stimulation is a sensitive method advisable for its application in preventive care in workers exposed to various industrial harmful substances.This paper is based upon the presentation made at the VIth Czechoslovak Congress of Neurology with international participation, Prague, September 1972.     

Mercury from crematoriums: human health risk assessment and estimate of total emissions in British Columbia

ObjectivesMercury occurs in the environment as a result of natural processes and human activities, including when individuals with amalgam dental fillings are cremated. This work aimed to estimate the quantity of mercury emitted to the atmosphere from crematoriums in British Columbia (BC) and assess the human health risk.MethodsA BC-specific emissions factor for mercury from crematoriums was developed and applied to an estimate of the quantity of mercury released annually to the atmosphere from crematoriums. The maximum ground-level mercury vapour concentrations resulting from crematorium emissions were estimated.ResultsIn BC, it is estimated that approximately 1.20 g of mercury is emitted to the atmosphere per body cremated and about 30,000 cremations were conducted in the province in 2016. It is estimated that almost 36 kg of elemental mercury was released to the atmosphere as a result. The maximum estimated peak short-term and long-term average ground-level mercury vapour concentrations associated with crematorium emissions were 0.31 μg/m³ and 7.9 × 10⁻³ μg/m³ respectively, which are far lower than the reference concentration (hazard quotient of less than 1).ConclusionMercury from crematoriums accounts for more than 7% of total mercury emissions to the atmosphere in BC, but risk assessment found no indication that ground-level exposures to elemental mercury vapour from crematoriums poses a significant risk to human health. If the number of cremations increases, it might reach considerable levels, highlighting the need for developing a national plan similar to other countries.     

Lung Cancer Mortality in a Cohort of Older Pulp and Paper Workers

Abstract

The occurrence of deaths due to lung cancer was studied among 883 white male workers from a pulp and paper company in northern New Hampshire. All subjects had participated in a longitudinal study of respiratory morbidity, and data from interviews were used to construct lifetime cigarette smoking and occupational histories. Most of the subjects had entered follow-up in the 1960s and, at that time, their mean age was 51 years and they had worked for the pulp and paper company a mean of 25 years. By the end of follow-up in 1992, the 512 deceased subjects included 35 whose underlying cause of death had been lung cancer. With an internal comparison, using the Cox proportional-hazards model, the hazard ratio for sulfite pulp mill work was 2.5 (95% CI 1.3–4.9), while controlling for the effects of age, cigarette smoking, and work in other parts of the pulping operation. In addition, the hazard ratio for the combination of > 35 pack-years of smoking and > 10 years sulfite mill work was greater than the product of the hazard ratios for each factor alone. While these findings are consistent with past asbestos exposure in the sulfite pulp mill environment, the absence of mesothelioma cases is inconsistent with this type of exposure.     

汞对男工生殖功能影响的研究

本文对某荧光灯厂３７名男工的生殖功能调查研究的结果表明：工人在作业环境汞浓度超标情况下作业，导致休内汞负荷水平的增高。血汞和精汞含量（分别为０．０５８１ｍｇ／Ｌ和０．０２７０ｍｇ／Ｌ）均比对照组（分别为０．０１０９ｍｇ／Ｌ和０．１３９ｍｇ／Ｌ增高，Ｐ＜０．０１。工人的生殖功能也受到一定的影响，表现为精液量减少，液化时间延长，精子的密度减小、一次射精子数减少、活精率下降，精子畸形率增高。同时，还观察     

An Inorganic Mercury Hazard in the Manufacture of Artificial Jewellery

An unusual inorganic mercury hazard in a factory manufacturing artificial jewellery is described. Considerable exposure of workers was confirmed by levels of up to 2,000 μg./1. of mercury in urine. The air concentration was also found to be correspondingly high, up to 0·5 mg./m.³ of mercury in the general atmosphere. Preventive measures have resulted in a slow fall in urinary concentrations over a period of several months. Despite the high results obtained, no worker showed any overt evidence of mercurialism. The significance of this is considered in the discussion and it is suggested that mercurialism may be due to a failure in excretion. If this is so, it would have a considerable effect on surveillance techniques; furthermore such a hypothesis may account for the anomalies that are well known in the surveillance of workers exposed to mercury.     

Canada's Asbestos Legacy at Home and Abroad

Abstract

Despite international efforts to block Canada's export of asbestos, the Canadian federal government continues to defend the economic interests of the asbestos industry. Ironically, Canadian asbestos miners, mill workers, and those engaged in a wide range of other occupations continue to suffer asbestos-related disease and premature death. Although there is an employerfunded compensation system in each province, many workers with mesothelioma and other asbestos-related diseases remain uncompensated. The export of Canadian asbestos to developing countries sets the stage for another preventable occupational disease epidemic that will manifest over the coming decades. There is growing support from the Canadian labor movement for an end to asbestos exportation and for a just transition strategy for the asbestos workers and their communities.     

The yellowed archives of yellowcake.

Extensive historical documentation of exposures and releases at government-owned energy facilities is a unique and valuable resource for analyzing and communicating health risks. Facilities at all stages of the atomic fuel cycle were the subject of numerous industrial hygiene, occupational health, and environmental assessments during the Cold War period. Uranium mines and mills on the Colorado Plateau were investigated as early as the 1940s. One such facility was the mill in Monticello, Utah, which began operation as a vanadium extraction plant in 1943 and was later adapted to recover uranium from carnotite ores. The mill ceased operation in 1960. The site was added to the federal Superfund list in 1986. ATSDR held public availability sessions in 1993 as part of its public health assessment process, at which several former mill workers voiced health concerns. An extensive literature search yielded several industrial hygiene evaluations of the Monticello mill and health studies that included Monticello workers, only two of which had been published in the peer-reviewed literature. In combination with the broader scientific literature, these historical reports provide a partial basis for responding to mill workers'' contemporary health concerns. The strengths and limitations of the available exposure data for analytical epidemiologic studies and dose reconstruction are discussed. As an interim measure, the available historical documentation may be especially helpful in communicating about health risks with workers and communities in ways that acknowledge the historical context of their experience.     

Air Pollution

The relationships among the mercury contents of salivary (parotid gland) secretions and simultaneously obtained blood and urine specimens were examined quantitatively among a group occupationally exposed to several mixed mercurials. Mercury concentrations in saliva averaged 1/4 and 1/10 of the bSood and urinary concentrations, respectively. A high correlation was observed between blood and parotid fluid mercury contents, inferring that the readily obtainable parotid secretion may be of diagnostic value as an indirect monitor of blood mercury as well as other foreign substances in the blood.     

Comparison of Two Questionnaires on Respiratory Symptoms in a Nicaraguan Population: Value in Diagnosis of Chronic Bronchitis

Abstract

Two questionnaires about respiratory symptoms were evaluated for reliability and ability to diagnose chronic bronchitis in a study population of 129 Nicaraguans (110 workers and 19 patients with chronic bronchitis). The first questionnaire (AQ) had symptom questions that were based on British Medical Research Council (MRC) questions, adapted to local Spanish. The second questionnaire (MRCQ) contained MRC symptom questions translated directly into Spanish. The reliability of the questions was measured in a test-retest procedure. The questionnaire-based diagnosis of chronic bronchitis was compared with the diagnosis made by a physician (for workers) or from the hospital records (for patients). The questions concerning symptoms in both questionnaires were of acceptable reliability. For the diagnosis of chronic bronchitis in workers, the AQ showed similar sensitivity, a somewhat higher specificity, and a substantially higher positive predictive value (90%) than the MRCQ (57%). Among the patients, the AQ identified 17 patients as positive (sensitivity 89%), while the MRCQ identified 15 (sensitivity 79%).     

Occupational exposure to metallic mercury in the dentist's office of a public primary health care clinic in the city of São Paulo

This paper discusses occupational exposure to metallic mercury among dentists and dental assistants, focusing on biological evaluation, effects on heaith, and environmental evaluation. Methods included visits to the clinic, hazard maps, urinary and environmental mercury measurements, and evaluation of health status. Results for the environment and work processes showed that mercury vapor concentrations impregnating surfaces and piping varied from 0.001 to 0.051 mg/m3 in air; occupational exposure with 62.5% of health workers having HgU ranging from 10 to 49 mg/l and 37.5% having HgU below 10 mg/l in 1994, while workers' previous measures (from 1992) were lower in every single case; an outflow of mercury and inadequate amalgamation due to a faulty amalgamator, the need for using a piece of chamois to obtain a homogeneous amalgam and remove excess mercury; the existence of combined hazards in the environment, and that all workers had been exposed since 1992. Results for workers' health showed a prevalence of symptoms from lesions to the central nervous system; central nervous system signs; and that mild-to-moderate chronic poisoning was found in 62.5% of workers.     

Byssinosis among jute mill workers

Although byssinosis in jute mill workers remains controversial, studies in a few jute mills in West-Bengal, India, revealed typical byssinotic syndrome associated with acute changes in FEV1 on the first working day after rest. The present study on 148 jute mill workers is reported to confirm the occurrence of byssinosis in jute mill workers. Work related respiratory symptoms; acute and chronic pulmonary function changes among exposed workers were studied on the basis of standard questionnaire and spirometric method along with dust level, particle mass size distributions and gram-negative bacterial endotoxins. The pulmonary function test (PFT) changes were defined as per the recommendation of World Health Organization and of Bouhys et al. Total dust in jute mill air were monitored by high volume sampling, technique (Staplex, USA), Andersen cascade impactor was used for particle size distribution and personal exposure level was determined by personal sampler (Casella, London). Endotoxin in airborne jute dust was analysed by Lymulus Amebocyte Lysate (LAL) "Gel Clot" technique. Batching is the dustiest process in the mill. Size distribution showed that about 70-80% dust in diameter of < 10 microm, 40-50%, < 5 microm and 10-20%, < 2 microm. Mean endotoxin levels found in hatching, spinning and weaving, and beaming were 2.319 microg/m3, 0.956 microg/ m3, 0.041 microg/m3 respectively and are comparable to the values obtained up to date in Indian cotton mills. Respiratory morbidity study reported typical byssinotic symptoms along with acute post shift FEV1 changes (31.8%) and chronic changes in FEV1 (43.2%) among exposed workers. The group with higher exposure showed significantly lower FVC, FEV1, PEFR and FEF25-75% values. The study confirmed the findings of the earlier studies and clearly indicated that the Indian jute mill workers are also suffering from byssinosis as observed in cotton, flask and hemp workers.     

Work factors facilitating working beyond state pension age: Prospective cohort study with register follow-up

Objectives:The demographic changes in Europe underline the need for an extension of working lives. This study investigates the importance of physical work demands and psychosocial work factors for working beyond the state pension age (65 years).Methods:We combined data from three cohorts of the general working population in Denmark (DWECS 2005 and 2010, and DANES 2008), where actively employed workers aged 55–59 years replied to questionnaires about work environment and were followed until the age of 66 years in the Danish AMRun register of paid employment. Using logistic regression analyses, we calculated prevalence ratios (PR) and 95% confidence intervals (CI) for the association between physical and psychosocial work factors and working beyond state pension age, adjusted for age, sex, cohort, cohabiting, sector, income, vocational education, working hours, lifestyle, and previous sickness absence.Results:Of the 2884 workers aged 55–59 years, 1023 (35.5%) worked beyond the state pension age. Higher physical work demands was associated with a lower likelihood (PR 0.69, 95% CI 0.58–0.82) and a good psychosocial work environment was associated with higher likelihood (average of 7 items: PR 1.81, 95% CI 1.49–2.20) of working beyond state pension age. Stratified analyses did not change the overall pattern, ie, a good overall psychosocial work environment – as well as several specific psychosocial factors – increased the likelihood of working beyond state pension age, both for those with physically active and seated work.Conclusion:While high physical work demands was a barrier, a good psychosocial work environment seems to facilitate working beyond state pension age, also for those with physically active work.     

Validity and reliability of a method for retrospective evaluation of chlorophenate exposure in the lumber industry

This paper describes the validity and reliability of a method to retrospectively assess exposure to antisapstain agents used in sawmills (chlorophenates). The method is based on experienced workers' estimates of exposure for each job title at the sawmill where they work. At a pilot mill, 10 randomly selected workers estimated the frequency and duration of exposures to chlorophenates for all 59 job titles. The reliability of their mean exposure estimates was very high, with an intraclass correlation coefficient for all raters of 0.91 (based on a calculated index of exposure). To assess validity, urinary chlorophenate levels were measured for 86% of the workers at the mill during the summer and/or fall, and compared to experienced workers' estimates of exposure. The correlation between workers' exposure estimates and the urinary chlorophenate levels for each job title were consistently above 0.65 for all analyses and greater than 0.72 when summer and fall urine sample results were averaged. The evidence indicates that the validity and reliability of worker exposure estimates are high enough to justify investigation of the method's generalizability to other sawmills.     

The Body Burden and Air Quality Standards

To evaluate the occupational hazard of the use of mercury by dentists, determinations were made of (1) the total mercury and vapor concentrations In a group of urban dental offices; and (2) the urinary excretion of mercury by the dentists. In a small but significant proportion (14%) of these offices, mercury concentrations were found In excess off the threshold limit value, Implying a lack of care in handling mercury., The average total mercury concentration was more than twice the average vapor concentration, clearly inferring that mercury particulates cannot be ignored in assessing the dental work environment. Absorption of mercury was evidenced by higher than “normal” urinary mercury levels, which correlated well with both the total ambient air concentrations and estimated exposure times.