Analysis of biogenic silica fibers from rice farming operations.
Scales-D; John-W; Lawson-R; Schmidt-J
Appl Occup Environ Hyg 1995 Aug; 10(8):685-691
A method was developed to quantitate biogenic silica (7631869) fibers. Particles were sampled over track etched filters that were prepared by the direct cleaning method for transmission electron microscope (TEM) analysis. The method was used to analyze about 100 samples from rice field operations. For sampling in the vicinity of field operations, it was advantageous to precede the filters with cyclones to exclude large, nonrespirable structures that obscured fibers on the filter. The optimum fiber loading on the filter was 100 to 1,000 fibers/square millimeter. To prevent overloading, the sampled volume was held to 30 liters through the 25 millimeter filters, providing a detection limit of 0.1 fiber/cubic centimeter. The method produced useful results in the rice emissions study. The present method represented a further development of the TEM method for biogenic silica fibers, the only general method currently available. The authors suggest that the method be regarded as provisional due to the lack of interlaboratory testing and use by others.
NIOSH-Publication; NIOSH-Cooperative-Agreement; Silica-dusts; Dust-exposure; Airborne-fibers; Analytical-methods; Sampling-methods; Agricultural-industry; Fibrous-dusts; Plant-substances;
Applied Occupational and Environmental Hygiene
University of California - Davis