2006 Fiscal Year Final Research Report Summary
The occupational health study of occupational respiratory diseases exposed to steel dust for a long time.
Project/Area Number |
17590515
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Hygiene
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Research Institution | National Institute of Occupational Safety and Health, Japan (JNIOSH) (2006) Kochi University (2005) |
Principal Investigator |
KODA Shigeki JNIOSH, Researcher, 有害性評価研究グループ, 上席研究員 (50205332)
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Project Period (FY) |
2005 – 2006
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Keywords | Occupational Health / Dust exposure / pneumoconiosis / Siderosis |
Research Abstract |
Tosa blacksmith has over four hundred-year history. The main products are kitchen knife, sickle, ax, hatchet, hoe, helm, saw, etc. The procedures of these products do not change until nowadays besides two processes, heating and forging with heavy oil furnace and automatic hammer, and rough grinding with grinder. In this paper, we would like to report pneumoconiosis exposed heavy metal dust in rough grinding. We evaluated respiratory dust exposures among Tosa blacksmith (n=32) in rough grinding. The level of dust exposure was 0.26-8.89 mg/m3. We analyzed the percentage of silica by X-ray diffraction method, and conducted the qualitative and quantitative analyses of heavy metal in exposed dust. The contaminating level of silica was 0.7-2.9%, and iron oxide III was 6.4-55.0%. The health examination of pneumoconiosis (n=41) was conducted, twenty five (61.0%) had pneumoconiosis signs in chest X-ray, and thirteen (31.7%) were slightly decreased in their lung functions. Two were severe pneumoconiosis. Their X-ray finding was numerous small fairly denses opacities (sized p) throughout the lung fields. Pneumoconiosis among Tosa blacksmith was diagnosed as siderosis. The number of siderosis patients is limited, and exposure limit has not been proposed yet. We could get information that a couple of workers had died of siderosis in this study. The mean of dust exposures among severe and died siderosis workers (4.07 mg/m3) was higher than one among slight siderosis and healthy workers (0.86 mg/m3). This result provided us important data for setting exposure limit of siderosis. And now, several workers have introduced low cost improvements in rough grinding process. The mean of dust exposures of improved workplaces (0.57 mg/m3) was lower than one of unimproved workplaces (2.39 mg/m3), and those were evaluated as effective and practical ones. As most of Tosa blacksmith are small-scaled and self-employed, it is very important to provide low cost improvements for preventing siderosis.
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