Monday, November 13, 2006
87-2

Toxin Concentration and Transport in Dust.

Richard Zartman, William Jaynes, Cary Green, Michael San Francisco, and John Zak. TX Tech Univ., Plant and Soil Science Dept., Lubbock, TX 79409-2122

Plant and microbial toxins, allergens, pollen, and spores have a much lower density than soil particles.� The lower density of these materials could facilitate effective transport and concentration in dust.� Aflatoxin concentrations as great as 41,000 �g/kg have been measured in the dust near combines, although grain crops containing 1,000 �g aflatoxin/kg must be destroyed.� A common health condition termed "farmers lung" is related to human exposure to allergens, pollen, spores, and mycotoxins found in dust.� Peanuts contain the allergenic protein, peanut seed lectin (PSL).� In this study, a small dust generation/collection device was used to collect dust fractions from soil samples containing PSL.� Soil samples (5-g) of Brownfield loamy fine sand (84% sand) and Pullman clay containing 5% peanut extract were used.� ELISA was used to measure PSL in the dust fractions.� Nitrogen surface areas were used as a measure of particle size. The collected soil fractions ranged from sand or sand-sized aggregates in the residual material (residual fraction) left in the dust generator to silt and clay in the last dust traps (trap3, trap4).� Residual fraction surface areas were lower than the original soil sample and progressively increased from trap1 to trap4.� Similarly, PSL was depleted in the residual fraction and concentrated (up to 11.6x) in the finer fractions (trap3, trap4).� Toxic materials in soil can be transported with soil dust and concentrated in the respirable dust fractions.