Exposure to amorphous silica fibers and other particulate matter during rice farming operations.
Lawson RJ; Schenker MB; McCurdy SA; Jenkins B; Lischak LA; John W; Scales D
Appl Occup Environ Hyg 1995 Aug; 10(8):677-684
Exposures to amorphous-silica (7631869) fibers greater than 5 micrometers in length were evaluated in the respirable dust fraction collected during rice farming operations. Area and personal samples for airborne amorphous-silica fibers were collected during rice harvest, burning, and field preparation. Area samples were also collected upwind and in a nearby town. The study indicated that employees were exposed to airborne amorphous-silica fibers in all phases of the rice farming operation. Personal exposures were found up to 1.9 fibers/cubic centimeter for fibers in the respirable dust range over 5 micrometers in length. Although the fibers did not have needle like or hair like shapes, ends of fibers were sometimes sharply pointed. The median fiber length was 2.8 micrometers, with a range from 0.5 to 20 micrometers. Ninety percent of the fibers were less than 9 micrometers in length. The median fiber width was 0.9 micrometers, with a range from 0.2 to 7 micrometers. Ninety percent of the fibers were less than 2.5 micrometers in width. The authors suggest that if employees avoid smoke exposure during stubble burning, the exposure to aerosolized biogenic silica fibers from the soil may contribute more to occupational exposure hazards than exposure during burning.
NIOSH-Publication; NIOSH-Cooperative-Agreement; Airborne-fibers; Agricultural-industry; Agricultural-workers; Fibrous-dusts; Biological-material; Airborne-particles; Occupational-exposure; Combustion-products;
Applied Occupational and Environmental Hygiene
University of California - Davis