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item Dungan, Robert - Rob
item Yates, Scott

Submitted to: Sustained Management of Irrigated Land for Salinity and Toxic Element Contr
Publication Type: Abstract Only
Publication Acceptance Date: 6/21/2001
Publication Date: 6/21/2001
Citation: Dungan, R.S., Yates, S.R. 2001. Volatilization and degradation of dimethylselenide applied to soil [abstract]. Sustained Management of Irrigated Land for Salinity and Toxic Element Contr.

Interpretive Summary:

Technical Abstract: In seleniferous terrestrial and aquatic environments, inorganic selenium (Se) oxyanions are biologically transformed into volatile Se compounds, which are subsequently released to the atmosphere. Dimethylselenide (DMSe), the dominant volatile Se compound emitted, plays a significant role in the biogeochemical cycling of Se, however, little is known about its fate and transport in soil environments. In this study, we investigated the effect of soil depth, moisture, and organic amendments on the transport of DMSe from packed soil columns. After 6 days, 56% of the DMSe injected at a depth of 10 cm was volatilized to the air, whereas only 38 and 25% were emitted to the air when the injection depth was 20 and 30 cm, respectively. The rate of DMSe volatilization was also dependent upon soil moisture, which decreased with increasing soil moisture content, however, the cumulative loss of DMSe was similar between moisture treatments after 2 days. The application of 1% (w/w) casein, glucose, or gluten to the top 5 cm soil layer was found to increase DMSe emissions by 10%. Experiments are currently underway to determine the combined effect of soil moisture, temperature, and organic amendments on DMSe degradation. Results will be available during meeting time. Information gained from this study will help improve upon our current understanding of the Se cycle and the optimum conditions required for maximum diffusion of DMSe through soil.