Skip to main content
U.S. flag

An official website of the United States government

Selenium speciation methods and application to soil saturation extracts from San Joaquin Valley, California

January 1, 1990

Methods to determine soluble concentrations of selenite, selenate, and organic Se were evaluated on saturation extracts of soil samples collected from three sites on the Panoche Creek alluvial fan in the western San Joaquin Valley, California. The methods were used in combination with hydride-generation atomic-absorption spectrometry for detection of Se, and included a selective chemical-digestion method and three chromatographic methods using XAD-8 resin, Sep-Pak C18 cartridge, and a combination of XAD-8 resin and activated charcoal. The chromatography methods isolate dissolved organic matter that can inhibit Se detection by hydride-generation atomic-absorption spectrometry. Isolation of hydrophobic organic matter with XAD-8 did not affect concentrations of selenite and selenate, and the isolated organic matter represents a minimal estimation of organic Se. Ninety-eight percent of the Se in the extracts was selenate and about 100% of the isolated organic Se was associated with the humic acid fraction of dissolved organic matter. The depth distribution of Se species in the soil saturation extracts support a hypothesis that the distribution of soluble Se and salinity in these soils is the result of evaporation from a shallow water table and leaching by irrigation water low in Se and salinity.

Publication Year 1990
Title Selenium speciation methods and application to soil saturation extracts from San Joaquin Valley, California
DOI 10.2136/sssaj1990.03615995005400020011x
Authors John L. Fio, Roger Fujii
Publication Type Article
Publication Subtype Journal Article
Series Title Soil Science Society of America Journal
Index ID 70047783
Record Source USGS Publications Warehouse
USGS Organization California Water Science Center