The coupled mobilizations and transport of dissolved organic matter and metals (Cu and Zn) in soil columns

L.Y.L. Zhao, R. Schulin, L.P. Weng, B. Nowack

Research output: Contribution to journalArticleAcademicpeer-review

52 Citations (Scopus)

Abstract

Dissolved organic carbon (DOC) is a key component involved in metal displacement in soils. In this study, we investigated the concentration profiles of soil-borne DOC, Cu and Zn at various irrigation rates with synthetic rain water under quasi steady-state conditions, using repacked soil columns with a metal-polluted topsoil and two unpolluted subsoils. Soil solution was collected using suction cups installed at centimeter intervals over depth. In the topsoil the concentrations of DOC, dissolved metals (Zn and Cu), major cations (Ca2+ and Mg2+) and anions ( and ) increased with depth. In the subsoil, the Cu and Zn concentrations dropped to background levels within 2 cm. All compounds were much faster mobilized in the first 4 cm than in the rest of the topsoil. DOC and Cu concentrations were higher at higher flow rates for a given depth, whereas the concentrations of the other ions decreased with increasing flow rate. The decomposition of soil organic matter resulted in the formation of DOC, , and and was the main driver of the system. Regression analysis indicated that Cu mobilization was governed by DOC, whereas Zn mobilization was primarily determined by Ca and to a lesser extent by DOC. Labile Zn and Cu2+ concentrations were well predicted by the NICA-Donnan model. The results highlight the value of high-resolution in-situ measurements of DOC and metal mobilization in soil profiles.
Original languageEnglish
Pages (from-to)3407-3418
JournalGeochimica et Cosmochimica Acta
Volume71
Issue number14
DOIs
Publication statusPublished - 2007

Keywords

  • nica-donnan model
  • humic substances
  • forest floor
  • ion-binding
  • heavy-metals
  • carbon
  • transport
  • adsorption
  • mechanisms
  • parameters

Fingerprint Dive into the research topics of 'The coupled mobilizations and transport of dissolved organic matter and metals (Cu and Zn) in soil columns'. Together they form a unique fingerprint.

Cite this