The effect of a "Nuisance" dust inhalation on lavagable lung cells

Particles for which no specific toxic effects are known are classified as "nuisance" dusts. A general threshold limit value has been established for an occupational exposure to those aerosols amounting to 6 mg/cubic meter in Germany and 5 mg/cubic meter in the U.S. respectively. The aim of the study was to investigate effects of a long-term exposure to nuisance dusts. In addition to lung clearance measurements, the functions of the alveolar leucocytes were studied. Three dusts were tested in parallel. Test materials were titanium dioxide, polyvinyl chloride powder (PVC) and iron powder at aerosol concentrations of 3.2, 8 and 20 mg/cubic meter. The exposure lasted up to 8 months. The used animals were female Fischer rats. Ten animals of each concentration group were taken for lung lavage. Lavagable lung cells were examined for the following parameters: total cell number, cell viability, phagocytic activity, adherence and chemotaxis tests, peroxidase staining and differential cell counti ng. The results showed an almost constant number of total cells over all groups except the highest PVC concentration group, the cell number of which increased significantly. The number of polymorphonuclear cells increased from low to higher concentrations. The results indicate more pronounced effects by PVC powder compared to TiO sub 2 and Fe dust. Previous experiments during exposure of the animals have shown that PVC reduces alveolar lung clearance