SILICATE PNEUMOCONIOSIS OF FARM-WORKERS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 40  (5) , 576-582
Abstract
Abnormal numbers of birefringent particles were found in the lungs of 7 patients (5 vineyard workers, 1 farmer and 1 rural resident) in association with a spectrum of early to late interstitial inflammation and fibrosis. Nodular granulomas of the type seen in silicosis were absent. Scanning electron microscopy and energy dispersive X-ray analysis of 177 individual particles (less than 5 .mu.m) in situ in the lungs of 4 of the patients showed mostly silicates (notably Al, Si and K), with a 5-10% SiO2. An analysis of particles less than 5 .mu.m from vineyard and non-vineyard soil showed lung and soil particles to have a similar composition. The presence of large amounts of silicates in the lung tissues, in association with chronic inflammation and fibrosis, implicates the silicates in the causation of the fibrosis. The silicate deposits may be a marker, reflecting a mixture of toxic soil additives or pesticides found in commercial clay silicate products or in dusts from the soil itself. The findings do not exclude lung pathology of a similar nature in regions outside of the farm.

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