Fluoride-Induced Mobilization and Leaching of Organic Matter, Iron, and Aluminum1
- Janina Polomski,
- H. Flühler and
- P. Blaser2
In order to demonstrate the effects of F-induced leaching of organic matter, Al, and Fe, different soil samples were percolated under laboratory conditions at constant flow with distilled water and various solutions containing F or Cl, applied as NaF, KF, Na5Al3 F14, KCl, and NaCl, respectively.
The three sets of experiments focus on the following questions: (i) Are the observed leaching losses primarily F-induced? (ii) How do they relate to the F concentrations of the solutions? and (iii) To what extent are calcareous soils resistant to and acid soils prone to F-induced leaching?
Total organic carbon (TOC), Fe, and especially Al were leached more effectively when the percolating solution contained F instead of Cl. The cationic composition of the solution was definitely less important than the concentration of dissolved F. For instance, the F-induced Al leaching loss from an acid clay soil was nine times larger than that of an equimolar NaCl solution. In the concentration range of 0 to 50 µg mL−1 dissolved F the peak concentrations of Al in the outflow samples varied from 0.2 to 26.0 µg Al mL−1. The leaching losses from the acid soil were significantly higher than those from the two calcareous soils. However, TOC leaching with distilled water was highest in the case of the severely F-contaminated calcareous soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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