Environ. Sci. Technol. 2011, 45, 262–267
Speciation of Se and DOC in Soil Solution and Their Relation to Se Bioavailability L I P I N G W E N G , * ,† F L O R A A L O N S O V E G A , † SUPRIATIN SUPRIATIN,† WIM BUSSINK,‡ AND WILLEM H. VAN RIEMSDIJK† Department of Soil Quality, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands and Nutrient Management Institute NMI BV, Agro Business Park 10, Postbus 250, 6700 AG, Wageningen, The Netherlands
Received May 12, 2010. Revised manuscript received October 22, 2010. Accepted November 16, 2010.
A 0.01 M CaCl2 extraction is often used to asses the bioavailability of plant nutrients in soils. However, almost no correlation was found between selenium (Se) in the soil extraction and Se content in grass. The recently developed anion Donnan membrane technique was used to analyze chemical speciation of Se in the 0.01 M CaCl2 extractions of grassland soils and fractionation of DOC (dissolved organic carbon). The results show that most of Se (67-86%) in the extractions (15 samples) are colloidal-sized Se. Only 13-34% of extractable Se are selenate, selenite and small organic Se (
