Selenium mobility and distribution in irrigated and nonirrigated alluvial soils

Soil Science Society of America Journal
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Abstract

Dissolution and leaching of soil salts by irrigation water is a primary source of Se to shallow groundwater in the western San Joaquin Valley, California. In this study, the mobility and distribution of selenite and selenate in soils with different irrigation and drainage histories was evaluated using sorption experiments and an advection-dispersion model. The sorption studies showed that selenate (15–12400 µg Se L−1) is not adsorbed to soil, whereas selenite (10–5000 µg Se L−1) is rapidly adsorbed. The time lag between adsorption and desorption of selenite is considerable, indicating a dependence of reaction rate on reaction direction (hysteresis). Selenite adsorption and desorption isotherms were different, and both were described with the Freundlich equation. Model results and chemical analyses of extracts from the soil samples showed that selenite is resistant to leaching and therefore can represent a potential long-term source of Se to groundwater. In contrast, selenate behaves as a conservative constituent under alkaline and oxidized conditions and is easily leached from soil.
Publication type Article
Publication Subtype Journal Article
Title Selenium mobility and distribution in irrigated and nonirrigated alluvial soils
Series title Soil Science Society of America Journal
DOI 10.2136/sssaj1991.03615995005500050020x
Volume 55
Issue 5
Year Published 1991
Language English
Publisher Soil Science Society of America
Contributing office(s) California Water Science Center
Description 8 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Soil Science Society of America Journal
First page 1313
Last page 1320
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