Abstract
A quantitative procedure for determining crocidolite and amosite in bulk or settled dust samples is described. Crocidolite and amosite are two of the three major types of asbestos fibers used in the United States asbestos industry. Each has a crystalline structure which provides a distinct x-ray diffraction pattern of sufficient intensity to be used in quantitative analysis. Quartz is used as the internal standard. A qualitative examination with the diffractometer establishes the presence of crocidolite or amosite in the samples and indicates possible interferences whose effects are minimized by using appropriate modifications of the quantitative procedure. Analysis of a series of known samples containing varied amounts of ground crocidolite provided a mean recovery of 99.6%. The lower end of the working range of the method is approximately 5% crocidolite. A separate series of known samples containing varied amounts of ground amosite provided a mean recovery of 96.88%.