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Modeling of Oxygen Transport and Pyrite Oxidation in Acid Sulphate Soils
Author(s) -
Bronswijk J. J. B.,
Nugroho K.,
Aribawa I. B.,
Groenenberg J. E.,
Ritsema C. J.
Publication year - 1993
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1993.00472425002200030020x
Subject(s) - pyrite , soil water , chemistry , leaching (pedology) , macropore , environmental chemistry , aeration , organic matter , acid mine drainage , soil science , mineralogy , environmental science , mesoporous material , biochemistry , organic chemistry , catalysis
Drainage and aeration of previously submerged acid sulphate soils could lead to oxidation and acidification of the soil and to related problems such as high Fe and Al concentrations in the soil solution. Agricultural production on these acidified soils is low. Furthermore, leaching of acid and toxic compounds from the soil to surface waters may cause environmental damage, such as degradation of ecologically valuable wetlands. A computer simulation model was developed to compute the rate and magnitude of pyrite oxidation in pyritic deposits such as acid sulphate soils, and the resulting acidity, soluble Fe and sulphates produced. The model includes vertical gaseous O 2 diffusion from the atmosphere into the soil macropores, lateral diffusion of dissolved O 2 into the soil matrix, and O 2 consumption inside the soil matrix by pyrite oxidation and organic matter decomposition. Oxygen consumption by pyrite oxidation was modeled by combining the equal diameter reduction model with an O 2 concentration dependent rate constant for pyrite oxidation. The model was validated by comparing computations and measurements in an acid sulphate soil subjected to drainage for a period of 440 d. Computed and measured pyrite content profiles, gaseous O 2 concentrations in the macropores and sulphate concentrations in the soil solution corresponded well. The present model, combined with a chemical equilibrium model and a solute transport model, can be applied to predict the (long‐term) effects of water management strategy on the quality of soils, drainage waters and surface waters in areas with pyritic deposits.