The recent development of diffusive gradients in thin film (DGT) for sediments has been extended to soil systems, primarily for assessing the bioaccessibility of metals. This paper presents a brief overview of the use of DGT and supporting data. This technique involves the use of a circular sheet of cation exchange resin covered by a diffusive film and filter paper, held together by a reusable plastic holder, that is brought into contact with moist soil. The mass of metal accumulated by the resin can be converted to an effective concentration using the DGT induced fluxes in sediments model. The technique has the potential to assess both quantity and intensity factors for metal supply from soil. Studies have shown that DGT extractable copper correlates better with plant tissue copper concentrations than several batch extractions across numerous soils. Indeed, one of the primary potential advantages of the DGT approach is that it should perform better across a wide range of soils and soil properties as compared to batch extractions. The technique has also been found useful in predicting zinc phytotoxicity thresholds in mine spoil materials and contaminated soils, and is superior to a batch extraction for this purpose. Metal uptake by vegetables has also been successfully predicted using DGT.
See more of Symposium--Revisiting Metal Behavior in Biosolids Amended Soils: Applying Knowledge Gained to an Understanding of Behavior of Metals in Soils Systems: III
See more of S02 Soil Chemistry
See more of The ASA-CSSA-SSSA International Annual Meetings (November 6-10, 2005)