Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 1996
Publication Date: N/A
Technical Abstract: Surface exposed shales of the Moreno and Kreyenhagen Formations are considered to be sources of selenium (Se) for soils of the west-central San Joaquin Valley, California. This study investigates Se speciation in the geologic series from the seleniferous shales, to the adjacent alluvial soils, the San Luis Drain sediment and the Kesterson evaporation pond soils. The percentages of soluble SeO4 and Se03 decreased and refractory Se increased in the tested shales and nearby alluvial soils as the total Se content decreased. In the drainage water contaminated San Luis Drain sediments and Kesterson pond 4, 7, and 11 soils, an opposite trend of Se enrichment was evident. The percentage of soluble SeO4= and SeO3= increased as total Se content decreased. In the nine materials tested, the total Se content decreased as the organic C content decreased suggesting a relationship between Se and organic C levels. An exponential relationship (R2 = 0.96) was determined for the sum of refractory Se and organic C contents, suggesting that the Se in the materials tested was highly associated with the soil organic matter fraction.