Crystalline Silica and Silicon Analyses from the NIOSH/EPA Coal/Diesel Study Using X-Ray Fluorescence Spectrometry and X-Ray Powder Diffraction.
The concentrations of crystalline silica (14808607) and total silicon (7440213) were determined for 12 animal exposure chambers used in the coal/diesel study. Chambers were sampled monthly or bimonthly. Of the 12 chambers, three contained clean air, three contained coal dust, three contained diesel exhaust and three contained mixtures of the dust and exhaust. Analysis for silica and silicon content in bulk coal dust samples was also made. All three clean air chambers showed no detectable silica concentration. The mean values of the three coal chambers fluctuated from 12 to 42 micrograms/cubic meter (microg/m3), but never exceeded the NIOSH standard of 50microg/m3. Coal/diesel and diesel only chambers had silica concentrations near or below the detection limit of 12microg/m3. Silicon concentrations were below detection levels in the clean air chambers. Some silicon was detected in coal chambers, but never exceeding 35microg/m3. Silicon concentrations in the coal/diesel chambers were near the detection limit of 11microg/m3. Diesel chambers gave silicon concentrations below the detectable limit. The bulk coal dust sample contained an average of 3.1 percent crystalline silica and 2.2 percent silicon concentrations.
NIOSH-Author; Diesel-exhausts; Diesel-emissions; Diesel-engines; Coal-dust; Environmental-contamination; Particulate-dust;
NTIS Accession No.
Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, 10 pages, 1 reference