The Copper-Mobilizing-Potential of Dissolved Organic Matter in Soils Varies 10-Fold Depending on Soil Incubation and Extraction Procedures

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• 作者：Fien Amery ; Fien Degryse ; Wim Degeling ; Erik Smolders ; Roel Merckx
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：April 1, 2007
• 年：2007
• 卷：41
• 期：7
• 页码：2277 - 2281
• 全文大小：100K
• 年卷期：v.41,no.7(April 1, 2007)
• ISSN：1520-5851

文摘

Copper is mobilized in soil by dissolved organic matter(DOM) but the role of DOM quality in this process is unclear.A one-step resin-exchange method was developed tomeasure the Cu-Mobilizing-Potential (CuMP) of DOM atpCu 11.3 and pH 7.0, representing background values. TheCuMP of DOM was measured in soil solutions of 13uncontaminated soils with different DOM extraction methods.The CuMP, expressed per unit dissolved organic carbon(DOC), varied 10-fold and followed the order water extracts> 0.01 M CaCl₂ extracts > pore water. Soil solutions,obtained from soils that were stored air-dry for a long timeor were subjected to drying-wetting cycles, had elevatedDOC concentration, but the DOM had a low CuMP.Prolonged soil incubations decreased the DOC concentrationand increased the CuMP, suggesting that most of theinitially elevated DOM is less humified and has lower Cuaffinity than DOM remaining after incubation. A significantpositive correlation between the specific UV-absorptionof DOM (indicating aromaticity) and CuMP was found forall DOM samples (R² = 0.58). It is concluded that the DOCconcentration in soil is an insufficient predictor for theCu mobilization and that DOM samples isolated from air-dried soils are distinct from those of soils kept moist.