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Accelerated volatilization rates of selenium from different soils
A Stork1, W A Jury, W T Frankenberger
1Department of Environmental Sciences, University of California, Riverside 92521, USA.
Biological Trace Element Research
|September 1, 1999
Summary
Soil amendments like zein and L-methionine can enhance selenium volatilization, a key process for removing toxic selenium from soils. This study explored different amendments to improve this natural remediation method.
Area of Science:
- Environmental Science
- Soil Science
- Biogeochemistry
Background:
- Selenium (Se) is a naturally occurring element that can accumulate to toxic levels in irrigated soils.
- Soil microorganisms can volatilize selenium (Se) into dimethylselenide (DMSe), offering a potential remediation pathway.
- Understanding soil amendments that enhance this volatilization is crucial for managing selenium contamination.
Purpose of the Study:
- To investigate the efficacy of different soil amendments in enhancing selenium volatilization from various soil types.
- To determine the optimal amendments for promoting gaseous selenium emissions as a soil remediation strategy.
Main Methods:
- Laboratory study using six different soils spiked with 75SeO3(2-).
- Tested amendments included two amino acids (DL-homocysteine, L-methionine), a carbohydrate (pectin), and a protein (zein).
- Gaseous 75Se emissions were quantified using activated carbon trapping and gamma counting.
Main Results:
- Selenium volatilization varied significantly by soil type, ranging from 1.2% to 9.0% in controls.
- Zein and L-methionine amendments markedly increased selenium volatilization, reaching up to 43% of applied Se.
- Pectin showed a moderate, sustained effect on volatilization rates, while DL-homocysteine had a minor impact.
Conclusions:
- Zein and L-methionine are highly effective soil amendments for enhancing selenium volatilization.
- The effectiveness of amendments and soil response to them are soil-specific.
- Enhanced selenium volatilization presents a promising bioremediation approach for contaminated soils.