On the problem of liquids and gases contaminated by fibers when using filters containing chrysotile

Experimental studies are reported dealing with the release of very fine chrysotile fibers from filter sheets containing chrysotile during the filtration of liquids and air. Using scanning electron microscopy as well as radioactivated chrysotile, concentrations of fibers released into aqueous filtrates, or into the air, were measured. It is shown that chrysotile fiber concentrations as high as 10⁶ to 10⁷ fibers/liter (～ 1 to 10 μg of chrysotile/liter) in the case of liquid filtration, and concentrations of ～ 0.1 fibers/ml (ca. 0.1 μg/m³) in the case of air filtration could be found or estimated.