Acute respiratory health effects among cement factory workers in Tanzania: an evaluation of a simple health surveillance tool

Prevalence of chronic respiratory symptoms among cement factory workers in Gauteng Province, South Africa

Cement workers are exposed to various kinds of occupational hazards, dust being the most hazardous. Despite certain exposure limits on the emission of air pollutants in place, several people die each year due to complications from respiratory disease. This study aimed to assess the prevalence of chronic respiratory symptoms among workers exposed to cement dust. A quantitative, descriptive cross-sectional design was employed among 81 workers from two cement production companies in Gauteng, South Africa in 2018. A self-administered questionnaire, anthropometric measurements, and a spirometry test were used as data collection tools. Data were analyzed using Wilcoxon rank sum, binary logistic regression, Pearson's chi-squared, and Fischer's exact tests. Respiratory symptoms such as wheezing, recurring blocked nose, sneezing/stuffy nose, fatigue/tiredness, rapid breathing, soreness/watery eyes, and breathlessness were significantly prevalent among participants from both facilities. Engineering and housekeeping control measures such as the use of High-Efficiency Particulate Air (HEPA) vacuums to clean up dust and proper use of Personal Protective Equipment (PPE) where workers are exposed to dust particles should be implemented.

Content of clinker and other materials in personal thoracic aerosol samples from cement plants estimated by scanning electron microscopy and energy-dispersive X-ray microanalysis

OBJECTIVES

To estimate the composition and exposure to clinker and other specific components in personal thoracic dust samples of cement production workers.

METHODS

A procedure for the classification of airborne particles in cement production plants was developed based on classification trees. For this purpose, the chemical compositions of 27,217 particles in 29 material samples (clinker, limestone, gypsum, clay, quartz, bauxite, iron source, coal fly ash, and coal) were determined automatically by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). The concentrations of the major elements in cement (calcium, aluminium, silicon, iron, and sulphur) were used for the classifications. The split criteria of the classification trees obtained in the material samples were used to classify 44,176 particles in 34 personal thoracic aerosol samples. The contents of clinker and other materials were estimated, and the clinker contents were analysed statistically for differences between job types and job tasks.

RESULTS

Between 64% and 88% of the particles from material samples were classified as actual materials. The material types with variable composition (clay, coal fly ash, and coal) were classified with the lowest consistency (64% to 67%), while materials with a more limited compositional variation (clinker, gypsum, and quartz) were classified more consistently (76% to 85%). The arithmetic mean (AM) of the clinker content in personal samples was 62.1%, the median was 55.3%, and 95% confidence interval (CI) was 42.6% to 68.1%. No significant differences were observed between job types. However, the clinker content in samples when workers handled materials with high clinker content was significantly higher than when materials with lower clinker content were handled, 85% versus 65% (P = 0.02). The limestone content was AM 14.8%, median 13.2% (95% CI 5.5 to 20.9), whereas the other materials were present with relative abundances of median ≤ 6.4%.

DISCUSSION

Automated particle analysis by SEM-EDX followed by classification tree analysis quantified clinker with fairly high consistency when evaluated together with raw materials that are expected to be airborne in cement production plants. The clinker proportions for job types were similar. Tasks a priori ranked by assumed clinker content were significantly different and according to expectations, which supports the validity of the chosen methodology.

CONCLUSIONS

The composition of personal samples of mineral aerosols in the cement production industry could be estimated by automated single particle analysis with SEM-EDX and classification by a classification tree procedure. Clinker was the major component in the thoracic aerosol that cement production workers were exposed to. Differences between job types were relatively small and not significant. The clinker content from tasks was in agreement with assumptions.

Lung Function and Respiratory Morbidity Among Informal Workers Exposed to Cement Dust: A Comparative Cross-Sectional Study

Background

Cement dust is a significant source of occupational exposure affecting lung function and respiratory health. A higher burden of respiratory morbidity is known among factory workers involved in cement production. Globally or from India, there are no estimates of this burden from informal workers exposed to cement dust.

Objective

To assess difference in lung function and respiratory symptoms among informal workers exposed to cement and those unexposed, using a comparative community based cross-sectional study from purposively selected areas in Delhi, India.

Methods

Using a portable spirometer we measured lung function and collected respiratory symptoms from conveniently sampled informal workers (n = 100) exposed to cement dust, 50 indoor informal workers (tailors), and 50 outdoor (vegetable) vendors. Regression analyses were performed to compare respiratory symptom score and lung function parameters, adjusted for age, body mass index, smoking, socioeconomic status, and years of occupational exposure.

Findings

Exposed workers had significantly lower lung function (PEF = -750 ml/s and -810 ml/s and FEV1/FVC (%) = -3.87 and -2.11) compared to indoor and outdoor groups, with three times higher chronic respiratory symptoms when compared to the unexposed groups. The cement dust exposure was observed to be associated with PEF (mean difference (MD) = -0.75L, 95%CI = -1.36 to -0.15, p = 0.01), %FEV1/FVC (MD = -3.87, 95%CI = -6.77 to -0.96, p = 0.03) and respiratory symptoms (p < 0.001).

Conclusion

This study generates evidence regarding the respiratory burden of occupational exposure among vulnerable informal workers. There is an urgent need for policy reforms to safeguard health from occupational exposures, especially among informal workers.

Standardized experimental model for cement dust exposure; tissue heavy metal bioaccumulation and pulmonary pathological changes in rats

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Exposure model is a reliable method of studying pulmonary toxicity of aerosolized xenobiotics.

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Deposition of particles beyond the conducting zone and tissue bioaccumulation accompany exposure to cement dust (ECD).

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Histoarchitectural alteration, body-organ weight discordance are indicators of acute ECD.

A controlled experimental model of exposure to aerosols particularly for cement dust was recently invented in a study from the laboratory that found high serum levels of heavy metals, decrease gastrointestinal motility, and altered hematological variables in cement dust exposed rats. However, reproducibility was not considered. This work aims at standardizing the model and investigating preliminary toxicological indicators. Thirty male rats used in this study were divided into 3 groups (n = 10). Group 1; control, while groups 2 and 3 were exposed to cement dust for 14 days and 28 days respectively. We assessed clinical signs of toxicity, tissue heavy metal concentration, histopathological, and body weight (BW) changes. We observed poor movement coordination, abnormal posture, cephalic fur loss. Evidence of ischemia and fibrotic pneumoconiosis were grossly observed in the lungs of the exposed groups. There was a significant increase in tissue level of heavy metals with pulmonary and gastric heavy metal content showing a trendy relationship during the period of the exposure as the value of Lead, Chromium, Cadmium, Iron, Calcium, and Nickel increased by nearly similar percentages in both tissues. Organs weights increased; the 14-day exposed (198 ± 31; 168 ± 22) and 28-day exposed (198 ± 22; 187 ± 26) groups had significantly reduced body weight at the first and second weeks of exposure compared to the control group (265 ± 26; 357 ± 40) respectively. Exposure to cement dust induced low bone density in the exposed rats (p < 0.05). Histopathological alterations include necrosis, inflammatory cellular infiltration, and alveolar hyperplasia suggestive of the proliferative response of pulmonary tissue to the dust. The operation of the standardized apparatus mimics a typical occupational exposure and the findings show that cement dust induces systemic toxicity via respiratory perturbation and body/organ weight discordance mediated by heavy metal bioaccumulation.

Lung Function Impairment in Construction Workers – Influence of Smoking and Exposure Duration

AIM: The objective of the study was to assess the influence of exposure duration and smoking on ventilatory impairment among construction workers. METHODS: A cross-sectional study was performed, including 83 construction workers aged 18–64 years, compared to equivalent number of office controls matched by age, workplace exposure duration, and smoking status. Data on chronic respiratory symptoms, work history, and smoking status were collected by standardized questionnaire, while lung functional testing of the examined subjects was performed by spirometry. RESULTS: Mean values of spirometric parameters were lower in construction workers compared to controls with statistical significance registered for maximal expiratory flow (MEF25), MEF50, and MEF75. Lung functions of construction workers have been found to decrease in relation to exposure duration but reached significance only for small airways changes. There was a significant difference in detected ventilatory impairment between exposed workers and controls for any type of ventilatory impairment, as well as obstructive and combined ventilatory pattern and obstructive ventilatory pattern in small airways. Obstructive ventilatory impairment was significantly associated with life-time smoking in construction workers, while obstructive ventilatory pattern in small airways was significantly associated with life-time smoking. The combined effect of daily smoking, life-time smoking, and number of cigarettes smoked daily was shown to have a significant influence in their development. The risk for obstructive ventilatory pattern in small airways among exposed subjects was about 4 fold higher in those exposed more than 20 years (odds ratio [OR] = 3.68 [1.01–14.59] confidence interval [CI] 95%), and about 2.5 fold higher in smokers (OR = 2.57 [0.92-7.25] CI 95%). Exposure duration, smoking and age had independent effect only on small airways changes and force expiratory volume in the 1st s/force vital capacity %. CONCLUSION: Our data suggest the importance of the joint effect of job exposure in construction and daily smoking on the development of lung function impairment and airflow limitation, being dominant, especially on small airways.

Effect of Exposure to Cement Dust among the Workers: An Evaluation of Health Related Complications

BACKGROUND:

Cement contains various types of chemicals in addition to lime and silica, and such chemicals cause different health complications and pathogenesis in addition to respiratory disorders. The most important occupational hazards for cement workers are allergy and complication related to respiratory system.

AIM:

The current study was performed by analysing the questionnaire distributed among the workers and also by the sputum collected from them to study the general health conditions and other life activities.

METHODS:

Sputum samples were assayed for cytological analysis by Hematoxylin and Eosin staining.

RESULTS:

In this study, it was observed that majority of these workers suffered from different types of respiratory complications, such as a cough, asthma and lung infections. In addition to this, few subjects showed allergy and other complication like hypertension, diabetes and backache. Moreover, cytological analysis of the sputum was made, and it was observed that majority of the subjects showed severe inflammation.

CONCLUSION:

Based on these finding, we concluded that long-term cement dust exposure and inhalation causes respiratory complications due to epithelial tissue damage and that can lead to secondary complications as well.

Comparative assessment of respiratory and other occupational health effects among elementary workers

Objective. This study was conducted to assess hazards faced by elementary workers. Methods. A questionnaire survey and a respiratory function test (spirometry) were carried out on 150 respondents. Results. Major hazards identified related to sharp objects, heavy weight lifting, thermally harsh conditions, working at height, whole body vibration, chemicals, pathogens, increased noise levels and confined space entry. Workers suffered from upper and lower respiratory disorder symptoms, digestive problems, optical and musculoskeletal issues, etc. Spirometric measurement showed obstructive lung disorders to be highest among construction workers (CW) (48%) followed by sanitation workers (SW) (32%) and solid waste pickers (SWP) (28%). Restrictive lung pattern was dominant among SW (56%) followed by SWP (46%) and CW (42%). The observed FEV₁/FVC in diseased SWP, SW and CW ranged from 51 to 96%, from 52 to 98% and from 31 to 99% respectively while observed mean FEV₁ was 2.15, 1.79 and 1.70 L, respectively. Conclusion. The study findings show that occupational exposure can significantly influence respiratory system impairment and contribute to other ailments among elementary workers. The study recommends use of appropriate protective equipment and regular medical examination for early recognition of any health risk so that timely interventions for effective management may be undertaken.

Association between exposure in the cement production industry and non-malignant respiratory effects: a systematic review

OBJECTIVES

Based on findings from a systematic literature search, we present and discuss the evidence for an association between exposure to cement dust and non-malignant respiratory effects in cement production workers.

DESIGN AND SETTING

Systematic literature searches (MEDLINE and Embase) were performed. Outcomes were restricted to respiratory symptoms, lung function indices, asthma, chronic bronchitis, chronic obstructive pulmonary disease, pneumoconiosis, induced sputum or fraction of exhaled nitric oxide (FeNO) measurements.

PARTICIPANTS

The studies included exposed cement production workers and non-exposed or low-exposed referents.

PRIMARY AND SECONDARY OUTCOMES

The searches yielded 594 references, and 26 articles were included. Cross-sectional studies show reduced lung function levels at or above 4.5 mg/m³ of total dust and 2.2 mg/m³ of respiratory dust. ORs for symptoms ranged from 1.2 to 4.8, while FEV₁/FVC was 1-6% lower in exposed than in controls. Cohort studies reported a high yearly decline in FEV₁/FVC ranging from 0.8% to 1.7% for exposed workers. 1 longitudinal study reported airflow limitation at levels of exposure comparable to ∼1 mg/m³ respirable and 3.7-5.4 mg/m³ total dust. A dose-response relationship between exposure and decline in lung function has only been shown in 1 cohort. 2 studies have detected small increases in FeNO levels during a work shift; 1 study reported signs of airway inflammation in induced sputum, whereas another did not detect an increase in hospitalisation rates.

CONCLUSIONS

Lack of power, adjustment for possible confounders and other methodological issues are limitations of many of the included studies. Hence, no firm conclusions can be drawn. There are few longitudinal data, but recent studies report a dose-response relationship between cement production dust exposure and declining lung function indicating a causal relationship, and underlining the need to reduce exposure among workers in this industry.

Lung function and dust in climbing halls: two pilot studies

In climbing halls, high levels of dust are found because magnesia powder is used to dry hands. Concerns have been raised about possible health effects after reports from asthmatics experiencing worsening of symptoms while or after climbing. We investigated acute and sub-acute effects of climbing in dusty halls on lung function in two pilot studies. The first study examined 109 climbers before and after a climbing activity that lasted at least 1 h. In the second study, 25 climbers from different age classes participated in a 2-day climbing competition. Of these, 24 agreed to take part in our investigation, but only 22 provided valid lung function tests on both days. The climbers underwent lung function tests before the first round of the competition (in the morning), after the second round approximately 3 h later and in the morning of the second day before the competition started again. In the first study, we found acute effects, a decline in lung function immediately after the exposure, likely due to protective reflexes of the bronchial muscles and stronger declines in persons with higher exhaled nitric oxide (NO) pre-climbing. In the second study, we also expected sub-acute effects on the next day due to inflammation. On the first day of the competition (second study), dust levels at a central monitor increased over time in a linear manner. Most of the dust was in the size range between 2.5 and 10 μm and dust levels of particulate matter (PM10) reached 0.5 mg/m3. There was a decline in lung function over 24 h in persons with higher exhaled NO levels pre-exposure. All spirometric parameters were affected though the effects were not statistically significant in all cases. Younger age classes started earlier in the morning. Because of the increasing trend in dust levels we expected stronger effects with higher numbers but for the acute effects the reverse was true, possibly because younger climbers use magnesia more or with less experience thus causing higher individual exposure. No differences by age or by time of the first climb were observed for the 24-h lung function change.

Total and respirable dust exposures among carpenters and demolition workers during indoor work in Denmark

Background

Within the construction industry the risk of lung disorders depends on the specific professions probably due to variations in the levels of dust exposure, and with dust levels depending on the work task and job function. We do not know the extent of exposure in the different professions or the variation between the different work tasks. The purpose of this study was therefore to assess if there were differences in dust exposure between carpenters and demolition workers who were expected to have low and high dust exposure, respectively.

Methods

Through interviews of key persons in the construction industry the most common work tasks were selected, and the concentration of dust during these tasks (indoors) were measured by personal sampling varying between 4 and 6 h of a working day. In total 38 measurements of total dust, and 25 of respirable dust on seven different work tasks were carried out for carpenters and 20 measurements of total dust, 11 of respirable dust and 11 of respirable crystalline silica dust on four different works tasks for demolition workers. Dust measurements were tested for differences using linear regression, t-test and one-way ANOVA.

Results

For carpenters the geometric mean for all the measurements of total dust was 1.26 mg/m³ (geometric standard deviation 2.90) and the respirable dust was 0.27 mg/m³ (geometric standard deviation 2.13). For demolition workers the geometric mean of total dust for all the measurements was 22.3 mg/m³ (geometric standard deviation 11.6) and the respirable dust was 1.06 mg/m³ (geometric standard deviation 5.64).

The mean difference between total dust for demolition workers and carpenters was 11.4 (95 % confidence interval 3.46–37.1) mg/m³. The mean difference between respirable dust for demolition workers and carpenters was 3.90 (95 % confidence interval 1.13–13.5) mg/m³.

Dust exposure varied depending on work task for both professions. The dustiest work occurred during demolition, especially when it was done manually.

Only few workers used personal respiratory protection and only while performing the dustiest work.

Conclusions

This study confirmed that the exposure to dust and especially total dust was much higher for demolition workers compared to carpenters.

Trial registration

(ISRCTN registry): The study is not a clinical trial and are thus not registered.

Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry

AIMS

The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette.

METHODS

Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers.

RESULTS

The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios.

CONCLUSIONS

The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the fractions.

Acute lung function response to dust in street sweepers

BACKGROUND

Sweepers are chronically exposed to dust raised during sweeping. Dust is regarded as the most influential agent and it is perceived as a frequent cause of respiratory system illness and may cause acute and chronic lung function impairment.

AIMS

The aim of this study was to determine the acute lung function changes in sweepers exposed to dust generated from street sweeping.

MATERIAL AND METHODS

This study was conducted in central Karnataka, India, on 25 female sweepers and 25 healthy female control subjects who were comparable in age, height and weight. The pulmonary function test was performed in controls, sweepers before and after sweeping, by using RMS medspiror and results were compared by Student's unpaired 't' test.

RESULTS

The results showed a significant reduction in percent predicted values and mean values of FVC, FEV1, PEFR, FEF25-75% and FEF 200-1200 between sweepers and their matched controls. Pulmonary function after sweeping also showed a significant decrease.

CONCLUSIONS

On comparing the pulmonary functions of sweepers before and after sweeping, it was concluded that inhalation of dust acutely affected the lung function of sweepers in India and that sweepers were at a risk of developing occupation related lung function impairment. We recommend that the workers should use protective face masks and do wet sweeping instead of dry sweeping during sweeping activity.

Cement-related particles interact with proinflammatory IL-8 chemokine from human primary oropharyngeal mucosa cells and human epithelial lung cancer cell line A549

Epidemiological studies have shown that respirable exposure to emitted cement particulate matter is associated with adverse health risk for human. The underlying mechanisms, however, are poorly understood. To examine the effect of cement, nine blinded cement-related particulates (<10 μm) were assessed with regard to their induction of the proinflammatory cytokines IL-6 and IL-8 in human primary epithelial cells (pEC) from oropharyngeal mucosa as well as from nonsmall-cell lung carcinoma (non-SCLC) cells A549. It was demonstrated that the cement specimens did not act cytotoxic as assessed by the lactate dehydrogenase (LDH) assay. The basal and IL-1β-induced IL-8 expression was suppressed, in contrast to an unchanged IL-6. At the transcript level the basal and induced IL-6 and IL-8 gene expression was not influenced by cement dust. To discover the mechanism by which cement influenced the IL-8 expression the following experiments were performed. Submerse exposure experiments have shown that the release of IL-8 was suppressed by cement dust. Furthermore, the incubation of IL-8 with cement-related specimens under cell-free condition led to a loss of immunoreactive IL-8. An immunological masking of IL-8 by free soluble components of respiratory epithelial cells was excluded. Thus, the decrease of IL-8 protein content after cement exposure seems to be a result of the adsorption of IL-8 protein to cement particles and the inhibition of IL-8 release. In conclusion, due to absent cytotoxic and inflammatory effects of cement-related specimens in both human pEC and A549 cell models it remains open how cement exposure may lead to the respiratory adverse effects in humans.

Dust exposure and respiratory symptoms among cement factory workers in the United Arab Emirates

This study was conducted in a cement factory in the United Arab Emirates to assess cement dust exposure and its relationship to respiratory symptoms among workers. A total of 149 exposed and 78 unexposed workers participated in this cross-sectional study. Information on demographic and respiratory symptoms was collected by questionnaire. Personal total dust levels were determined by the gravimetric method. Concentration of the total dust ranged between 4.20 mg/m(3) in the crushers and 15.20 mg/m(3) in the packaging areas, and exceeded the exposure limit in the packaging and raw mill areas. The prevalence of respiratory symptoms was higher among the exposed workers, but the difference from that of unexposed workers was statistically significant only for cough (19.5%; OR=4.5; 95%CI=1.5-13.2), and phlegm (14.8%; OR=13.3; 95%CI=1.8-100.9). Cough and phlegm were found to be related to exposure to dust, cumulative dust and smoking habit, while chronic bronchitis was related to smoking habit. The few factory workers (19.5%) who used masks all the time had a lower prevalence rate of respiratory symptoms than those not using them. High dust level was the only variable that influenced the workers to use the mask all the time. It is recommended that control measures be adopted to reduce the dust and workers should be encouraged to use respiratory protection devices during their working time.

Variability in total dust exposure in a cement factory

Exposure assessment is a main component of epidemiologic studies and variability in exposure. This assessment is considered as a common approach for such phenomenon. A total of 129 dust samples were collected randomly from 197 personnel from a cement factory located in Ilam province, during 2009 in Iran. The between- and within-group components of variability were determined to assess the contrast in exposure level between the Similar Exposure Groups (SEGs) and to calculate the within-worker geometric standard deviation of the theoretical exposure-response slope. Results were analyzing by one-way random effects model. According to the mentioned model, the probability of long-term mean exposure exceeding to the occupational exposure limit (OEL) was assessed for each SEGs. The arithmetic means (AM) of total dust levels ranged from 0.04 to 39.37 mg/m(3). The geometric means (GM) of total dust were higher in the crusher (20.84 mg/m(3)), packing (17.29 mg/m(3)), kiln (16.78 mg/m(3)), cement mill (14.90 mg/m(3)), and raw mill (10.44 mg/m(3)). However, the figures for the maintenance and administration parts were 3.77 mg/m(3) and 1.01 mg/m(3), respectively. The random effects model data demonstrated that the F-value calculated was greater than the critical F-value approximately 59% of the variability in the exposure was due to differences between groups. Based on these finding, the order of probability of the long-term mean exposure exceeding (Z) to the OEL of 10 mg/m(3) for total dust which were in kiln (100%), packing (100%), cement mill (90%), crusher (73%), raw mill (60%) administration (2.3%) and the maintenance parts (0%).

Excessive exposure to dust among cleaners in the Ethiopian cement industry

Personal exposure to dust in cement factories occurs at all stages of the production process and is likely to vary between different stages of the process. Previous studies on cement production have focused on dust exposure among process operators and machine attendants. This study characterizes personal exposure to total and respirable dust among production workers in two cement factories in Ethiopia, with particular focus on cleaners. In Ethiopian cement plants, flow lines are partly open, and cleaning workers use brooms and shovels to remove dust that has settled on floors and machines. Personal full-shift samples of total (n = 150) and respirable dust (n = 36) were taken in the breathing zones of 105 cement workers. Samples of total and respirable dust were collected on 37-mm cellulose acetate filters of closed-face cassettes and in plastic respirable cyclones, respectively. In both factories, cleaners had significantly higher exposures to total and respirable dust than other production workers. Among cleaners, the geometric means for total and respirable dust exposure were 549 and 6.8 mg/m(3) in Factory A, and 153 and 2.8 mg/m(3) in Factory B. Temporal variability (within-worker) dominated the variability in the cleaners' total dust exposures. The distance from machines while performing cleaning tasks and the fraction of working hours spent on cleaning explained about 73% of the temporal variability in total dust exposure among cleaners. Only 7% of the production workers used respiratory protective devices. Preventive measures are needed to reduce dust exposure.

A cross-shift study of lung function, exhaled nitric oxide and inflammatory markers in blood in Norwegian cement production workers

OBJECTIVES

To study possible effects of aerosol exposure on lung function, fractional exhaled nitric oxide (FeNO) and inflammatory markers in blood from Norwegian cement production workers across one work shift (0 to 8 h) and again 32 h after the non-exposed baseline registration.

METHODS

95 workers from two cement plants in Norway were included. Assessment of lung function included spirometry and gas diffusion pre- and post-shift (0 and 8 h). FeNO concentrations were measured and blood samples collected at 0, 8 and 32 h. Blood analysis included cell counts of leucocytes and mediators of inflammation.

RESULTS

The median respirable aerosol level was 0.3 mg/m(3) (range 0.02-6.2 mg/m(3)). FEV(1), FEF(25-75%) and DL(CO) decreased by 37 ml (p=0.04), 170 ml/s (p<0.001) and 0.17 mmol/min/kPa (p=0.02), respectively, across the shift. A 2 ppm reduction in FeNO between 0 and 32 h was detected (p=0.01). The number of leucocytes increased by 0.6×10(9) cells/l (p<0.001) across the shift, while fibrinogen levels increased by 0.02 g/l (p<0.001) from 0 to 32 h. TNF-α level increased and IL-10 decreased across the shift. Baseline levels of fibrinogen were associated with the highest level of respirable dust, and increased by 0.39 g/l (95% CI 0.06 to 0.72).

CONCLUSIONS

We observed small cross-shift changes in lung function and inflammatory markers among cement production workers, indicating that inflammatory effects may occur at exposure levels well below 1 mg/m(3). However, because the associations between these acute changes and personal exposure measurements were weak and as the long-term consequences are unknown, these findings should be tested in a follow-up study.

Cement dust exposure and acute lung function: a cross shift study

Background

Few studies have been carried out on acute effects of cement dust exposure. This study is conducted to investigate the associations between current "total" dust exposure and acute respiratory symptoms and respiratory function among cement factory workers.

Methods

A combined cross-sectional and cross-shift study was conducted in Dire Dawa cement factory in Ethiopia. 40 exposed production workers from the crusher and packing sections and 20 controls from the guards were included. Personal "total" dust was measured in the workers' breathing zone and peak expiratory flow (PEF) was measured for all selected workers before and after the shift. When the day shift ended, the acute respiratory symptoms experienced were scored and recorded on a five-point Likert scale using a modified respiratory symptom score questionnaire.

Results

The highest geometric mean dust exposure was found in the crusher section (38.6 mg/m³) followed by the packing section (18.5 mg/m³) and the guards (0.4 mg/m³). The highest prevalence of respiratory symptoms for the high exposed workers was stuffy nose (85%) followed by shortness of breath (47%) and "sneezing" (45%). PEF decreased significantly across the shift in the high exposed group. Multiple linear regression showed a significant negative association between the percentage cross-shift change in PEF and total dust exposure. The number of years of work in high-exposure sections and current smoking were also associated with cross-shift decrease in PEF.

Conclusions

Total cement dust exposure was related to acute respiratory symptoms and acute ventilatory effects. Implementing measures to control dust and providing adequate personal respiratory protective equipment for the production workers are highly recommended.

Study on the oxidative stress status among cement plant workers

The cement industry is considered as a major pollution problem because of dust and particulate matter emitted at various steps of cement production. In the present study, volunteer male workers from a cement factory were studied for oxidative and nitrosative stress biomarkers in relation to their serum levels of aluminum (Al) and chromium (Cr). The subjects were divided into two groups of direct and indirect exposure. Subject who worked in production steps were considered as direct exposure group, and those who worked in administration building were considered as indirect exposure group. For comparison, healthy subjects at the same age and socioeconomic status were tested as a control group. Serum levels of lipid peroxidation (LP), total antioxidant capacity (TAC), total thiol molecules (TTM), and nitric oxide (NO) as well as Al and Cr were measured. The results indicated a significant increase in Al ( P = 0.001) and Cr ( P = 0.009) levels in direct-exposed workers in comparison to healthy control group. Further, a significant increase in Al ( P = 0.002) and Cr ( P = 0.009) levels was observed in direct-exposed workers as compared to indirect-exposed one. Serum levels of TTM and TAC were significantly lower in both direct- and indirect-exposed groups in comparison to healthy control group ( P = 0.00). Serum TTM and TAC were significantly lower in direct-exposed workers as compared to indirect-exposed ones ( P = 0.00 and P = 0.024, respectively). There was no significant difference on the level of LP and NO among groups. A correlation was found between serum level of Cr, TAC, and platelets between direct- and indirect-exposed groups ( P < 0.05). Further correlation was found among serum level of Cr and those of TTM, platelets, and chronic disease ( P < 0.05). Chronic disease had a significant influence adjusted to other predictor variables on the post-shift values of Al ( P < 0.05). Although plasma levels of Al and Cr were found in normal ranges, analyses confirm their role in impairment of TMM and TAC.

Effect of Metalworking Fluid Mist Exposure on Cross‐Shift Decrement in Peak Expiratory Flow

Exposure to metalworking fluids (MWF) mist and cross-shift decrements in peak expiratory flow (PEF) were evaluated and their relationship was analyzed using several statistical methods. The objective of this study was to assess workers, exposure to MWF mineral mist and to find the MWF mist level for predicting cross-shift decrements in PEF. A total of 158 workers handling water-soluble MWF had MWF mist exposures with an arithmetic mean (AM) of 0.4 mg/m(3) (range: LOD-13.5 mg/m(3)), and 9.2% of workers (219) showed a cross-shift decline greater than 10% in PEF. MWF mist exposure and cross-shift decrements in PEF that were matched (n=113) were linearly significantly associated (R(2)=0.036, p=0.045) although the correlation was quite weak (r=0.189). We found a slight increase in cross-shift decrements in PEF with increased exposure to MWF aerosol mass concentration. The MWF mist exposure level was categorized into two or three groups by the cutoffs of either the National Institute for Occupational Safety and Health's Recommended Exposure Level (NIOSH REL: 0.5 mg/m(3)) or the American Conference of Governmental Industrial Hygienists Notice of Intended Change (ACGIH NIC: 0.2 mg/m(3)). The cross-shift decrement in PEF observed from workers exposed to > or =0.2 mg/m(3) was slightly higher than that of the exposure level of < or =0.2 mg/m(3) at p=0.207 while significant differences among categorized exposure groups (2 categories, <0.5 and > or =0.5 mg/m(3), or 3 categories, <0.2, 0.2-0.5 and > or =0.5 mg/m(3)) were not detected. In order to find out whether there is a specific level that allows us to predict cross-shift decrements in PEF, several statistical models were constructed. Logistic regression showed that the MWF concentration, whether treated as a continuous variable or a categorical variable, was not significantly associated with cross-shift decrements dichotomized by a cutoff of either 10% or 15% in PEF. We couldn't find evidence of a significant PEF decrement increase with increasing exposure category. Thus, we concluded that PEF decrements measured in workers exposed to MWF mist concentrations greater than either 0.2 mg/m(3) or 0.5 mg/m(3) was not significantly different from those found in workers exposed to lower MWF mist concentrations. Further study is needed to establish the level of MWF mineral mist predicting non-malignant respiratory health effects.