Apatite Control of Phosphorus Release to Runoff from Soils of Phosphate Mine Reclamation Areas

作者：Kuo Yi Ming; Harris Willie G^*; Munoz Carpena Rafael; Rhue R Dean; Li Yuncong

来源：Water, Air, and Soil Pollution, 2009, 202(1-4): 189-198.

DOI：10.1007/s11270-008-9969-4

• Dissolved phosphorus
• Specific surface area
• Apatite
• Dissolution
• Reclamation area
• Surface runoff

Phosphorus (P) in runoff can pose a water quality risk in phosphate mine reclamation areas. High dissolved P (DP) concentrations (about 0.4-3.0 mg L-1) in runoff from these areas and high equilibrium P concentrations for the soils led us to hypothesize that P release is controlled by dissolution of apatite rather than by desorption mechanisms. Objectives were to (a) verify via chemical- and solid-state assessments that P in the reclamation soils is mainly in the form of apatite and (b) examine evidence that DP concentrations in runoff water from these soils is controlled by apatite dissolution. Soil analyses included total P (TP), P sorption isotherms, P fractionation, mineralogy, and P distribution by particle size classes. Runoff samples were chemically characterized and modeled for speciation. Results showed high TP concentrations and the presence of apatite. The Ca- and Mg-bound P accounted for about 95% of TP. Runoff samples were undersaturated with respect to apatite. A strong relationship between calculated apatite specific surface area and measured DP concentration in water extracts is supportive of other evidence that apatite dissolution is a major factor controlling P release from these soils. Data indicate that these soils will be a long-term P source rather than sink. Results are applicable to other phosphate mine reclamation sites and illustrate the need to account for compositional differences between reconstructed soils on reclaimed mining sites and their indigenous soil analogues.

• 出版日期2009-9