TY - JOUR
T1 - Rhizospheric Mobilization and Plant Uptake of Radiocesium from Weathered Micas: II. Influence of Mineral Alterability
AU - Thiry, Yves
AU - Gommers, Annick
AU - Delvaux, Bruno
A2 - Vandenhove, Hildegarde
N1 - Score = 10
PY - 2005/11/7
Y1 - 2005/11/7
N2 - Acute K depletion in the rhizosphere can lead to increased root uptake of radiocesium. Two processes can govern this increase: the very low uptake of potassium and the weathering of Cs-fixing clay minerals. Their respective importance is, however, unknown. We investigated the effects of these processes on radiocesium mobilization by roots of willow (Salix viminalis L.) from three micas: muscovite, biotite, and phlogopite. Willows were grown in a mixed quartz–mica substrate with the three respective 134Cs-contaminated micas as sole sources of potassium and radiocesium. After 7 wk of plant growth, the micas were partially weathered. The degree of mica weathering and the prevalent potassium concentration in the solution increased in the order muscovite (5–11 µM K) <biotite (25–32 µM K) <phlogopite (25–35 µM K). The mobilization and root uptake of radiocesium were negligible with muscovite but increased in the same order. These results show that mica weathering directly and chiefly governs the mobility of radiocesium in K-depleted rhizosphere soil. The low mobility of trace Cs in the muscovite rhizosphere is linked with the dioctahedral character of this mica, and hence to its very low alterability.
AB - Acute K depletion in the rhizosphere can lead to increased root uptake of radiocesium. Two processes can govern this increase: the very low uptake of potassium and the weathering of Cs-fixing clay minerals. Their respective importance is, however, unknown. We investigated the effects of these processes on radiocesium mobilization by roots of willow (Salix viminalis L.) from three micas: muscovite, biotite, and phlogopite. Willows were grown in a mixed quartz–mica substrate with the three respective 134Cs-contaminated micas as sole sources of potassium and radiocesium. After 7 wk of plant growth, the micas were partially weathered. The degree of mica weathering and the prevalent potassium concentration in the solution increased in the order muscovite (5–11 µM K) <biotite (25–32 µM K) <phlogopite (25–35 µM K). The mobilization and root uptake of radiocesium were negligible with muscovite but increased in the same order. These results show that mica weathering directly and chiefly governs the mobility of radiocesium in K-depleted rhizosphere soil. The low mobility of trace Cs in the muscovite rhizosphere is linked with the dioctahedral character of this mica, and hence to its very low alterability.
KW - mica weathering
KW - Radiocaesium
KW - rhizosphere
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_27161
UR - http://knowledgecentre.sckcen.be/so2/bibref/2911
U2 - 10.2134/jeq2004.0407
DO - 10.2134/jeq2004.0407
M3 - Article
SN - 1537-2537
VL - 34
SP - 2174
EP - 2180
JO - Journal of Environmental Quality
JF - Journal of Environmental Quality
ER -