TY - JOUR

T1 - Aluminium sulphate solubility in acid forest soils in Denmark

AU - Gundersen, Per

AU - Beier, Claus

PY - 1988

Y1 - 1988

N2 - Ion leaching in 3 sandy spruce forest soils of different origin and pH was investigated in the laboratory. Zero-tension lysimeters containing undisturbed soil columns of varying soil depth were subjected to H2SO4 loadings for a period of 9 weeks. The analysis of the resulting leachate supports the hypothesis that Al-sulphate minerals may form in acidic soils when exposed to acid (H2SO4) deposition. In the B horizon of a glaciofluvial sandy soil (pH 4.2), both H+ and sulphate ions were retained to maintain 2pH + PSO4 = 11.9 in the leachate solutions. This relation between H+ and sulphate activity may be due to an adsorption mechanism or a precipitation mechanism. The precipitation mechanism is favored by the good fit of leachate composition to the conditions for jurbanite [AlOHSO4] formation from gibbsite [Al(OH)3]. In the B horizon of a sandy till at pH 3.7, the Al in soil solution (0.5 mmol L−1) was leached with sulphate. As the sulphate load was increased, some sulphate was retained. This may also be due to the dissolution and precipitation of an Al-sulphate mineral. The ion activity products of leachate solutions from the B horizon of this soil were close to the pKs reported for jurbanite. The conditions for the possible existence and/or formation of Al-sulphate minerals in acidic soils are discussed.

AB - Ion leaching in 3 sandy spruce forest soils of different origin and pH was investigated in the laboratory. Zero-tension lysimeters containing undisturbed soil columns of varying soil depth were subjected to H2SO4 loadings for a period of 9 weeks. The analysis of the resulting leachate supports the hypothesis that Al-sulphate minerals may form in acidic soils when exposed to acid (H2SO4) deposition. In the B horizon of a glaciofluvial sandy soil (pH 4.2), both H+ and sulphate ions were retained to maintain 2pH + PSO4 = 11.9 in the leachate solutions. This relation between H+ and sulphate activity may be due to an adsorption mechanism or a precipitation mechanism. The precipitation mechanism is favored by the good fit of leachate composition to the conditions for jurbanite [AlOHSO4] formation from gibbsite [Al(OH)3]. In the B horizon of a sandy till at pH 3.7, the Al in soil solution (0.5 mmol L−1) was leached with sulphate. As the sulphate load was increased, some sulphate was retained. This may also be due to the dissolution and precipitation of an Al-sulphate mineral. The ion activity products of leachate solutions from the B horizon of this soil were close to the pKs reported for jurbanite. The conditions for the possible existence and/or formation of Al-sulphate minerals in acidic soils are discussed.

U2 - 10.1007/bf00279472

DO - 10.1007/bf00279472

M3 - Journal article

VL - 39

SP - 247

EP - 261

JO - Water, Air, and Soil Pollution: Focus

JF - Water, Air, and Soil Pollution: Focus

SN - 1567-7230

ER -