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Component analyses of grain dusts that contribute to occupational lung injury.

Marinez-A; Cosma-G; Kullman-G; Lewis-D; Gardner-H
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :66-67
We have developed a lung cell model to explore the pathways of oxidative injury in lung alveolar macrophage (AM) cells exposed to respirable grain dusts. There is a twofold purpose for performing these studies: (1) identify major toxic components of grain dusts and (2) define underlying pathways of inflammatory lung injury. Airborne, respirable wheat and corn dusts were collected at 10 grain elevators in southeastern and northeastern Colorado during harvest. High flow air pumps, set at 1.7 L/min, were used with 10 cm cyclones to collect dust samples. Samples were analyzed for levels of bacterial endotoxin via chromogenic limulus amebocyte lysate, crystalline silica via X-ray diffraction, and 20 metals via inductively coupled plasma/mass spectrometry. Surprisingly, aluminum levels were found to exceed the part per thousand level, while iron was the second most common metal detected in grain dusts. As expected, endotoxin levels varied with site and grain; however, we have found imperfect correlations between levels of endotoxin contamination in dusts and the severity of the following inflammatory responses in dust-exposed AM cells: (1) production of hydrogen peroxide and (2) synthesis of cytokines interleukin-1 /6 and TNF-alpha as measured by immunoassay. These studies suggest the presence of other toxic components in grain dusts, possibly related to levels of metals and silica. We have designed a multiple linear regression model to evaluate the strengths of associations between individual components of the dusts and the severity of inflammatory responses in AM cells. Concern over current permissible exposure limits of organic dusts may be partially resolved by identification of their major toxic components, rather than by monitoring total respirable dust mass.
Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders; Grain-dusts; Agriculture; Analytical-models; Lung-cells; Oxidative-processes; Alveolar-cells; Respirable-dust; Toxic-materials; Airborne-dusts; Dust-analysis; Dust-collection; Dust-samplers; Dust-sampling; Cyclone-air-samplers; Bacterial-dusts; Endotoxins; Laboratory-techniques; Laboratory-testing; Mass-spectrometry; Immune-reaction; Hydroperoxides; Metal-compounds; Silica-dusts; Organic-dusts
14808-60-7; 7429-90-5; 7439-89-6
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American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia