Abstract
OBJECTIVES: Little information is available on the quantitative risks of respiratory disease from quartz in airborne dust in the heavy clay industry. Available evidence suggested that these risks might be low, possibly because of the presence in the dust of other minerals, such as illite and kaolinite, which may reduce the harmful effects of quartz. The aims of the present cross sectional study were to determine among workers in the industry (a) their current and cumulative exposures to respirable mixed dust and quartz; (b) the frequencies of chest radiographic abnormalities and respiratory symptoms; (c) the relations between cumulative exposure to respirable dust and quartz, and risks of radiographic abnormality and respiratory symptoms. METHODS: Factories were chosen where the type of process had changed as little as possible during recent decades. 18 were selected in England and Scotland, ranging in size from 35 to 582 employees, representing all the main types of raw material, end product, kilns, and processes in the manufacture of bricks, pipes, and tiles but excluding refractory products. Weights of respirable dust and quartz in more than 1400 personal dust samples, and site histories, were used to derive occupational groups characterised by their levels of exposure to dust and quartz. Full size chest radiographs, respiratory symptoms, smoking, and occupational history questionnaires were administered to current workers at each factory. Exposure-response relations were examined for radiographic abnormalities (dust and quartz) and respiratory symptoms (dust only). RESULTS: Respirable dust and quartz concentrations ranged from means of 0.4 and 0.04 mg.m-3 for non-process workers to 10.0 and 0.62 mg.m-3 for kiln demolition workers respectively. Although 97% of all quartz concentrations were below the maximum exposure limit of 0.4 mg.m-3, 10% were greater than this among the groups of workers exposed to most dust. Cumulative exposure calculations for dust and quartz took account of changes of occupational group, factory, and kiln type at study and non-study sites. Because of the importance of changes of kiln type additional weighting factors were applied to concentrations of dust and quartz during previous employment at factories that used certain types of kiln. 85% (1934 employees) of the identified workforce attended the medical surveys. The frequency of small opacities in the chest radiograph, category > or = 1/0, was 1.4% (median reading) and seven of these 25 men had category > or = 2/1. Chronic bronchitis was reported by 14.2% of the workforce and breathlessness, when walking with someone of their own age, by 4.4%. Risks of having category > or = 0/1 small opacities differed by site and were also influenced by age, smoking, and lifetime cumulative exposure to respirable dust and quartz. Although exposures to dust and to quartz were highly correlated, the evidence suggested that radiological abnormality was associated with quartz rather than dust. A doubling of cumulative quartz exposure increased the risk of having category > or = 0/1 by a factor of 1.33. Both chronic bronchitis and breathlessness were significantly related to dust exposure. CONCLUSIONS: Although most quartz concentrations at the time of this study were currently below regulatory limits in the heavy clay industry, high exposures regularly occurred in specific processes and occasionally among most occupational groups. However, there are small risks of pneumoconiosis and respiratory symptoms in the industry, although frequency of pneumoconiosis is low in comparison to other quartz exposed workers.
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- Dourmashkin R., Patterson S., Shah D., Oxford J. S. Evidence of diffusion artefacts in diaminobenzidine immunocytochemistry revealed during immune electron microscope studies of the early interactions between influenza virus and cells. J Virol Methods. 1982 Sep;5(1):27–34. doi: 10.1016/0166-0934(82)90094-5. [DOI] [PubMed] [Google Scholar]
- KEPPLER J. F., BUMSTED H. E. A dust study of the building brick industry in Indiana. AMA Arch Ind Hyg Occup Med. 1950 Dec;2(6):735–741. [PubMed] [Google Scholar]
- Le Bouffant L., Daniel H., Martin J. C., Bruyère S. Effect of impurities and associated minerals on quartz toxicity. Ann Occup Hyg. 1982;26(1-4):625–634. [PubMed] [Google Scholar]
- Myers J. E., Cornell J. E. Respiratory health of brickworkers in Cape Town, South Africa. Symptoms, signs and pulmonary function abnormalities. Scand J Work Environ Health. 1989 Jun;15(3):188–194. doi: 10.5271/sjweh.1863. [DOI] [PubMed] [Google Scholar]
- Myers J. E., Garisch D., Louw S. J. Respiratory health of brickworkers in Cape Town, South Africa. Radiographic abnormalities. Scand J Work Environ Health. 1989 Jun;15(3):195–197. doi: 10.5271/sjweh.1862. [DOI] [PubMed] [Google Scholar]
- Myers J. E., Lewis P., Hofmeyr W. Respiratory health of brickworkers in Cape Town, South Africa. Background, aims and dust exposure determinations. Scand J Work Environ Health. 1989 Jun;15(3):180–187. doi: 10.5271/sjweh.1866. [DOI] [PubMed] [Google Scholar]
- Rajhans G. S., Budlovsky J. Dust conditions in brick plants of Ontario. Am Ind Hyg Assoc J. 1972 Apr;33(4):258–268. doi: 10.1080/0002889728506638. [DOI] [PubMed] [Google Scholar]
- Sluis-Cremer G. K. Pneumoconiosis in South Africa. S Afr Med J. 1972 Mar 18;46(12):322–324. [PubMed] [Google Scholar]
- Soter N. A., Wasserman S. I., Austen K. F. Cold urticaria: release into the circulation of histamine and eosinophil chemotactic factor of anaphylaxis during cold challenge. N Engl J Med. 1976 Mar 25;294(13):687–690. doi: 10.1056/NEJM197603252941302. [DOI] [PubMed] [Google Scholar]
- Wiecek E., Gościcki J., Indulski J., Stroszejn-Mrowca G. Pył i choroby zawodowe w cegielniach. Med Pr. 1983;34(1):35–45. [PubMed] [Google Scholar]