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Title: Use of Headspace Techniques to Monitor the Volatilization and Degradation of Dimethylselenide

item Dungan, Robert - Rob
item Yates, Scott

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/26/2006
Publication Date: 11/13/2006
Citation: Dungan, R.S., Yates, S.R., Frankenberger, Jr, W. 2006. Use of Headspace Techniques to Monitor the Volatilization and Degradation of Dimethylselenide. [abstract]. Abstract #331, p. 41.

Interpretive Summary:

Technical Abstract: Dimethylselenide (DMSe) is a highly volatile gas that is produced by indigenous microorganisms in seleniferous soils and sediments; however, little is known about the soil conditions that affect the persistence of DMSe and its transport to the atmosphere. In this study we investigated the effect of moisture content, temperature, and organic amendments on the degradation of soil-applied DMSe. The degradation of DMSe was entirely a result of biological mechanisms, but changes in temperature and soil moisture content had little influence on the degradation rate. In contrast, amending soil with either 1% casein or gluten (by weight) had an inhibitory effect on the degradation of DMSe. After 18 days, 2.1 and 2.6 times more DMSe was present in the casein- and gluten-amended soil, respectively. The transport of DMSe in packed soil columns was also investigated. Increasing the depth to soil surface was found to significantly decrease the amount of DMSe transported to the air. After 6 days, 57% of DMSe injected 10 cm below the soil surface was volatilized. At an injection depth of 20 and 30 cm the cumulative emissions were reduced by 38 and 51%, respectively. In columns containing 1% casein or gluten in the top 5 cm of soil the cumulative loss of DMSe was about 9% higher than in unamended soil. Increasing our understanding of the soil conditions that influence the gaseous diffusion of DMSe should help in determining the feasibility of using Se volatilization as a remediation technique.