The incidence of artificial stone-related silicosis among interior decoration workers in different countries / 中华劳动卫生职业病杂志

In this paper, 177 cases of artificial stone-related silicosis in interior decoration workers from Israel, Spain, USA, Italy and Australia were analyzed. Interior decoration workers were from small businesses (or workshops), engaged in kitchen and/or bathroom artificial stone countertops cutting, grinding, polishing and other reprocessing. In the working environment, the content of crystalline silica in artificial stone was more than 70%, and the concentration of silica dust exceeded the relevant standards. Most workplaces used dry cutting without ventilation and dust removal and other dust-proof measures, and most workers did not wear qualified respiratory protective equipment. Taking comprehensive measures such as wet operation, ventilation and dust removal, and individual protection can effectively prevent the occurrence of artificial stone-related silicosis.

Avaliação da eficácia de sistema de ventilação local exaustora utilizado no controle de sílica cristalina em indústria de borracha de silicone / Evaluation of the effectiveness of a local exhaust ventilation system employed for controlling crystalline silica in a silicone rubber industry

Resumo Introdução: os sistemas de ventilação local exaustora (SVLE) podem ser utilizados para controlar a exposição ocupacional a agentes químicos. Contudo, muitas vezes são indevidamente concebidos, instalados ou operados, tornando-se ineficazes. Objetivo: avaliar a eficácia de um SVLE empregado para controle da sílica cristalina utilizada na produção da borracha de silicone. Métodos: a avaliação aplicada foi baseada em procedimentos técnicos descritos em literatura referencial de ventilação industrial e sistematizada em três etapas - inspeção inicial, avaliação dos parâmetros do SVLE e avaliação ambiental. Foi realizado um teste de campo em um SVLE instalado em misturador de sílica e silicone utilizado em uma empresa de fabricação de borracha de silicone no Estado de São Paulo. Resultados: as etapas de inspeção e avaliação dos parâmetros do SVLE apontaram deficiências no projeto, na operação e na manutenção do sistema, referendadas por sua reduzida velocidade de captura. Na avaliação ambiental, foram encontradas concentrações de sílica cristalina na fração respirável acima do valor de referência adotado. Conclusão: o estudo ratificou a necessidade de projeto, instalação, operação e manutenção dos SVLE estarem em consonância com os princípios de engenharia de ventilação a fim de se obter o funcionamento eficaz do sistema.

Abstract Introduction: local exhaust ventilation (LEV) systems can be used for controlling chemical occupational exposure. However, sometimes they are improperly designed, installed or operated, becaming ineffective. Objective: to evaluate the effectiveness of a LEV used for controlling crystalline silica employed in the production of silicone rubber. Methodology: the assessment carried out was based on technical procedures described in the industrial ventilation reference literature and was systematized in three steps - initial inspection, evaluation of LEV parameters and environmental assessment. A field test was applied in a LEV installed in a silica and silicone mixer of a rubber manufacturing company located in the state of São Paulo, Brazil. Results: the inspection and evaluation steps of the LEV parameters pointed out deficiencies in the design, operation and maintenance of the system, testified by its reduced capture velocity. Regarding the environmental assessment, concentrations of crystalline silica above the reference value were found in the respirable fraction. Conclusion: the study confirmed that, for the LEV effective functioning, their design, installation, operation and maintenance have to be in conformity with the principles of ventilation engineering.

Silica exposure and work-relatedness evaluation for occupational cancer in Korea

Crystalline silica has been classified as a definite carcinogen (Group 1) causing lung cancer by the International Agency for Research on Cancer (IARC). In Korea, crystalline silica has been the most common causal agent for workers to apply to the Korea Workers' Compensation and Welfare Service (KWCWS). We used KWCWS data to evaluate workers' crystalline silica exposure levels according to their occupations and industries, and reviewed research papers describing the dose-response relationship between cumulative exposure levels and lung cancer incidence. In addition, we reviewed lung cancer cases accepted by the KWCWS, and suggest new criteria for defining occupational cancer caused by crystalline silica in Korea. Rather than confining to miners, we propose recognizing occupational lung cancer whenever workers with pneumoconiosis develop lung cancer, regardless of their industry. Simultaneous exposure and lag time should also be considered in evaluations of work-relatedness.

Crystalline Silica Promotes Rat Fibrocyte Differentiation in Vitro, and Fibrocytes Participate in Silicosis in Vivo / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>The aim of this study was to investigate the effects of SiO2 on fibrocytes and whether fibrocytes participate in silicosis in vivo.</p><p><b>METHODS</b>A macrophagocyte (AM)/fibrocyte coculture system was established, and AMs were treated with 100 μg/mL SiO2. Flow cytometry was used to detect the number of fibrocytes. Real-time PCR was performed to measure the expression of collagen I, collagen III, and α-SMA mRNA. The levels of collagen I, collagen III, and TGF-β1 protein were determined by ELISA. Immunohistochemical staining was performed to measure α-SMA protein expression. A rat silicosis model was induced by intratracheal instillation of SiO2. Lung histopathological evaluation was conducted using HE and Masson's trichrome staining after 1 and 9 weeks. The number of fibrocytes in peripheral blood or lung tissue of rat was detected by flow cytometry. Double-color immunofluorescence was applied to identify fibrocytes in the lung tissue.</p><p><b>RESULTS</b>Peripheral blood monocytes were found to differentiate into fibrocytes in vitro in a time-dependent manner, and exposure to crystalline silica might potentiate fibrocyte differentiation. In addition, fibrocytes were able to migrate from peripheral blood to the lung tissue, and the number of fibrocytes was increased after SiO2 exposure.</p><p><b>CONCLUSION</b>Silica exposure potentiates fibrocyte differentiation, and fibrocytes may participate in silicosis in vivo.</p>

Systemic sclerosis due to crystalline silica exposure among jewelry workers in Korea: two case reports

BACKGROUND: Occupational exposure to crystalline silica is a potential risk factor for various systemic autoimmune diseases including systemic sclerosis. The etiology of systemic sclerosis is not conclusively known, but there are epidemiological studies that show the relationship between exposure to crystalline silica and risk of systemic sclerosis. Here we report, for the first time, two cases of crystalline silica-related systemic sclerosis in patients who worked in crystal processing in the jewelry-manufacturing field. CASE PRESENTATION: Case 1 is a 57-year-old man who had worked mainly in crystal processing for multiple jewelry-processing companies for 17 years, since the age of 15 years. He contracted tuberculosis at the age of 25 years and showed Raynaud's phenomenon of both the hands and feet at age 32 years. Digital cyanosis and sclerosis developed at approximately age 41 years. The patient was diagnosed with systemic sclerosis at age 48 years. Case 2 is a 52-year-old man who worked in crystal processing for various jewelry-processing companies for 7 years, since the age of 23 years. He first showed signs of cyanosis in the third and fourth digits of both hands at age 32 years, was diagnosed with Raynaud's syndrome at age 37 years, and was diagnosed with systemic sclerosis at age 38 years. Crystal processing is a detailed process that involves slabbing and trimming the selected amethyst and quartz crystals, which requires close proximity of the worker's face with the target area. In the 1980s and 1990s, the working hours were 12 h per day, and the working environment involved 15 workers crowded into a small, 70-m2 space with poor ventilation. CONCLUSION: Two workers who processed crystals with a maximum crystalline silica content of 56.66% developed systemic sclerosis. Considering the epidemiological and experimental evidence, exposure to crystalline silica dust was an important risk factor for systemic sclerosis. An active intervention is necessary to reduce exposure in similar exposure groups in the field of jewelry processing.

Epidemiologic Characteristics of Compensated Occupational Lung Cancers among Korean Workers

An understanding of the characteristics of occupational lung cancer is important to establish policies that prevent carcinogen exposure and to compensate workers exposed to lung carcinogens. This study analyzed the characteristics of occupational lung cancers in workers who were compensated under the Industrial Accident Compensation Insurance Law between 1994 and 2011. A total of 179 occupational lung cancers were compensated. The main carcinogenic exposure was asbestos, followed by crystalline silica and hexavalent chromium. The mean exposure duration and latency were 19.8 and 23.2 yr. The most common industry was manufacturing, followed by construction and transportation. The most common occupation was maintenance and repair, followed by foundry work, welding, painting, and spinning or weaving. Although asbestos was predominant carcinogen, the proportion of these cases was relatively low compared to other developed countries. Proper surveillance system is needed to monitor occupational lung cancer and improve prevention measures.

Protein expression in silica dust-induced transdifferentiated rats lung fibroblasts / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To analyze the expression of different proteins in free silica-induced transdifferentiated rat lung fibroblasts.</p><p><b>METHODS</b>Rat lung fibroblasts and alveolar macrophages were cultured. A transdifferentiation model of rat lung fibroblasts was established. Free silica was used as a stimulator for rat lung fibroblasts. Changes in α-SMA were detected by immunohistochemistry and Western blot, respectively. Protein of lung fibroblasts was extracted and analyzed by two-dimensional electrophoresis (2-DE).</p><p><b>RESULTS</b>Six protein spots were identified by mass spectrometry, including glyceraldehyde 3-phosphate-dehydrogenase, peroxiredoxin 5, heterogeneous nuclear ribonucleoprotein A2, transgelin 2, keratin K6 and vimentin.</p><p><b>CONCLUSION</b>Some proteins are changed in free silica-induced transdifferentiated rat lung fibroblasts.</p>

Two Cases of Lung Cancer in Foundry Workers

BACKGROUND: Iron and steel foundry workers are exposed to various toxic and carcinogenic substances including crystalline silica, polycyclic aromatic hydrocarbons, and arsenic. Studies have been conducted on lung cancer in iron and steel founding workers and the concentration of crystalline silica in foundries; however, the concentration of crystalline silica and cases of lung cancer in a single foundry has never been reported in Korea. Therefore, the authors report two cases of lung cancer and concentration of crystalline silica by the X-ray diffraction method. CASE PRESENTATION: A 55-year-old blasting and grinding worker who worked in a foundry for 33 years was diagnosed with lung cancer. Another 64-year-old forklift driver who worked in foundries for 39 years was also diagnosed with lung cancer. Shot blast operatives were exposed to the highest level of respirable quartz (0.412 mg/m3), and a forklift driver was exposed to 0.223 mg/m3. CONCLUSIONS: The lung cancer of the two workers is very likely due to occupationally related exposure given their occupational history, the level of exposure to crystalline silica, and epidemiologic evidence. Further studies on the concentration of crystalline silica in foundries and techniques to reduce the crystalline silica concentration are required.

Cohort Mortality Study in Three Ceramic Factories in Jingdezhen in China / 华中科技大学学报（医学）（英德文版）

To investigate the health impacts of crystalline silica mixed dust and other potential occupational hazards on workers in ceramic factories, a cohort study of 4851 workers registered in the employment records in 3 ceramic factories in Jingdezhen city of China between 1972 and 1974 was identified2 The cohort mortality was traced throughout 2003 with an accumulation of 128970.2 person-years, revealed 1542 deaths. Standardized mortality ratios (SMRs) were calculated for the main causes of death by using Chinese national mortality rates as reference. The mortality from all causesin three ceramic factories was 12.0‰ and the cumulative mortality was 31.8%. Malignant neoplasm,cardiovascular diseases, respiratory diseases, infectious diseases were the first four illnesses that threaten workers' life, and they accounted for 73.2% of all deaths. The resultsof this study showed that the standardized mortality ratio for all subjects was 1.02, which is very close to that expected on the basis of the China national mortality rates. Statistically significant mortality excesses for respiratory disease (SMR=1.36), pneumoconiosis (SMR=37.34), infectious disease (SMR=5.70) and pulmonary tuberculosis (SMR=3.88) were observed. The mortality of 2938 dust-exposed workers was higher than that of 1913 non dust-exposed workers. Except for pneumoconiosis, the mortality from lung cancer, non-malignant respiratory diseases and pulmonary tuberculosis in dust-exposed workerswere significantly increased as compared with that in non-exposed workers, and the relative risks(RRs) were 1.86 (1.16-2.99), 2.50 (1.84-3.40), 1.81 (1.34-2.45). The exposure-response relationships between cumulative dust exposure level and mortality from all causes, colorectal cancer, lung cancer, respiratory diseases, and pulmonary tuberculosis were also identified. The findings indicatedthat silica mixed dust in ceramic factories has harmful impact on the workers' health and life span in ceramic factory.

Characteristic of Talldust in Sand-Storm in Northwest Area of China / 环境与健康杂志

Objective To survey free crystalline silica[SiO_2(F)]content,particle size and water-soluble components concentration in the sand-dust storm dust,in order to prevent large-scale non-occupational silicosis(desert lung) prevalence in northwest desert area of China.Methods Atmospheric dust(falldust) were collected in Hetian,Minqin,Zhongwei and Lanzhou city when sand-dust storm befallen and free crystalline silica,particle size ratio and water-soluble components were analyzed according to GB 5748—1985.Results The rate of SiO_2(F) component was over 50%in the original sand,the rate of SiO2(F) component was from 17.36% to 48.09%in the falldust of sand-dust storm,the falldust belongs to crystal dust.The inhaleble particle(particles with amedian diameter of 0.5-10?m) ratio was from 63.3%to 84.1%.The water-soluble components concentration increased as sand-dust storm moving.C1,SO_4~(2-) and NO_3~- content was from 220?g/g,870?g/g and 230?g/g of Hetian to 980?g/g,5 400?g/g and 1 400?g/g of Lanzhou(P

Autoproliferation of Fibroblast by Exposure to Crystalline Silica - Evaluation by H2O2 and PDGF-AA and TGF beta / 대한산업의학회지

OBJECTIVES: The aim of this study is to find out the activity of autoproliferation of ratfibroblast exposed to crystalline silica and the role of mediators secreted from rat fibroblast. METHODS: The effect of alpha-quartz on production of growth factor (platelet-derived growth factor-AA and transforming growth factor beta)from rat fibroblasts were evaluated by ELISA and immunocytochemical analysis. Gene expression of these growth factors in rat fibrobast exposed to crystalline silica was evaluated by RT-PCR. Furthermore, fibroblast proliferation by culture supernatant of rat fibroblast was assayed by the neutral red test. RESULTS: The amounts of H2O2 and growth factors synthesized in rat fibroblasts were significantly increased by the stimulation of crystalline silica(alpha-quartz), which showed the dose-dependent manner to the concentration of alpha-quartz with the maximum response at the dosage of 100 microgram/cm2. The result of RT-PCR demonstrated that alpha-quartz induced gene expression of PDGF-AA and TGFbeta in rat fibroblast. We also found that supernatant of alpha-quartz-cocultured rat fibroblast induced a significant proliferation of fibroblast. CONCLUSION: Crystalline silica directly induce functional change in fibroblast such as increased release of reactive oxygen species and growth factors. The products of these functional change promote fibroblast proliferation via autocrine loop.