Exposure assessment of smoke and biogenic silica fibers during sugar cane harvesting in Hawaii.
Boeniger MF; Fernback J; Hartle R; Hawkins M; Sinks T
Appl Occup Environ Hyg 1991 Jan; 6(1):59-66
A study of occupational exposures occurring during sugar cane burning and harvesting was conducted. Environmental and breathing zone samples were collected during cane burning and harvesting operations at a field on the lower slopes of Haleakala Crater, Maui, Hawaii and analyzed for total dust, inorganic fibers, aluminum (7429905), iron (7439896), polycyclic aromatic hydrocarbons (PAHs), carbon-monoxide (630080), and organic carbon. Soil samples were analyzed for their mineral content. Breathing zone samples were collected at a nearby sugar mill and analyzed for total dust and biogenic silica (7631869) fibers. Bulk leaf samples were analyzed for inorganic fibers. Airborne particulate concentrations near the burning field were 20 to 70 times higher than those measured in areas remote from burning. Organic carbon was found in all smoke samples. Aluminum and iron were found in most smoke samples. The ratio of aluminum to iron in the smoke samples matched that of the soil samples. Organic carbon, aluminum, and iron were not detected in air samples remote from burning. No PAHs were detected. Low concentrations of airborne inorganic fibers were found in less than half of the samples. Maximum carbon-monoxide concentrations were only 5 parts per million. Total airborne particulate concentrations measured during harvesting ranged from 0.2 to 3.4mg/m3. Amorphous silica fibers at concentrations ranging up to 56000 fibers per cubic meter were detected. Most fibers had diameters of 0.5 to 2.0 microns and lengths of 10 to 40 microns. Airborne particulate concentrations at the sugar mill ranged from 0.1 to 2.1mg/m3. Fiber concentrations ranged up to 8350mg/m3. The fibers appeared to be silica. Bulk dry cane leaf samples contained about 10 million fibers per gram. The fibers appeared to be silica and most had diameters of 0.25 to 1.0 micron and lengths of 2.5 to 15 microns. The authors conclude that sampling for organic carbon, iron, and aluminum appears to be the best method for characterizing smoke from sugar cane fires. The health effects resulting from biogenic silica fibers are unknown and should be investigated.
NIOSH Author; Agricultural workers; Occupational exposure; Fibrous dusts; Chemical analysis; Combustion products; Plant substances; Agricultural products; Silica dusts
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Applied Occupational and Environmental Hygiene