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Fixation of radiocaesium in an acid brown forest soil
Author(s) -
Maes E.,
Delvaux B.,
Thiry Y.
Publication year - 1998
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1046/j.1365-2389.1998.00139.x
Subject(s) - vermiculite , soil horizon , organic matter , chemistry , weathering , clay minerals , soil water , environmental chemistry , soil organic matter , geology , mineralogy , soil science , geochemistry , paleontology , organic chemistry
Summary The OAh and Ah horizons of acid brown and podzolic forest soils are reported to fix more radiocaesium than the mineral B horizons beneath them. We determined the respective influence of organic matter and clay minerals on the magnitude of Cs + retention in a strongly acid brown forest soil in Belgium. The soil contained mica throughout the profile. Vermiculite was identified in the OAh and Ah horizons, and hydroxy interlayered vermiculite (HIV) in the Bw horizon. The OAh and Ah clay fraction retained much more Cs + than the Bw horizon. The extraction of Al interlayers by Na‐citrate resulted in a marked increase in Cs + fixation in the Bw clays as well as the collapse of the vermiculitic layers after K + saturation. Organic matter had a strong but indirect effect on Cs + fixation. In the Bw horizon, acid weathering of layer silicates releases free Al and produces HIV minerals in which Al polymers block the access of radiocaesium onto Cs + ‐specific sites. In OAh and Ah horizons, free Al is complexed by organic acids. Consequently, the interlayer specific sites remain accessible for Cs + fixation.