Quantitative relationship of fecal asbestos to asbestos exposure

A method is descirbed for isolating chrysotile fibers from feces and counting them with an electron microscope. The detection limit was 150,000 fibers per gram feces; average recovery was 85.5%. When the method was used to check the asbestos in feces of people subjected to industrial exposure vs. controls, the means were significantly different (p less than 0.02). Duplicate fecal samples were found to check within an average of +/- 31.1% of their means.