Shenber M A, Johanson K J
Swedish University of Agricultural Sciences, Department of Radioecology, Uppsala.
Sci Total Environ. 1992 Mar 31;113(3):287-95. doi: 10.1016/0048-9697(92)90007-f.
Plant availability of radiocaesium is usually high immediately after incorporation in a soil. However, for some Swedish soils, e.g, peat soils, a high radiocaesium uptake in plants has also been observed during a second growth period after contamination. For these soils the reduction in the plant availability of the nuclide seems to be a slow process. In the last two years the mineral zeolite has become of interest and has been tested as a caesium binding agent in both animal and in soil-plant systems. The aim of this study was to evaluate the time dependency and the effect of zeolite on the plant availability of radiocaesium in a peat soil-plant system. The pot experiments designed for this purpose were carried out in a climate chamber, using winter wheat as the test crop. A significant reduction of the uptake of 134Cs was obtained in wheat when increasing amounts of zeolite were added. This reduction in plant uptake, up to a factor of 8, might depend on two factors. One is that zeolite has reduced the activity concentration of radiocaesium in the soil solution available to the plant roots. The other is that the potassium added with the natural zeolite increased the degree of dilution of caesium in the soil solution. Also, increasing equilibration time for caesium in soil before sowing brought about an effective reduction in the caesium uptake.
放射性铯在土壤中混合后，其对植物的有效性通常在短期内较高。然而，对于一些瑞典土壤，如泥炭土，在污染后的第二个生长季节，也观察到植物对放射性铯的高吸收情况。对于这些土壤，该核素对植物的有效性降低似乎是一个缓慢的过程。在过去两年中，矿物沸石受到关注，并已在动物和土壤-植物系统中作为铯结合剂进行了测试。本研究的目的是评估在泥炭土-植物系统中，沸石对放射性铯植物有效性的时间依赖性和影响。为此设计的盆栽试验在气候室中进行，使用冬小麦作为试验作物。当添加的沸石量增加时，小麦对134Cs的吸收显著降低。植物吸收的这种降低，高达8倍，可能取决于两个因素。一是沸石降低了植物根系可利用的土壤溶液中放射性铯的活度浓度。另一个是天然沸石中添加的钾增加了土壤溶液中铯的稀释程度。此外，播种前土壤中铯的平衡时间增加，有效降低了铯的吸收。
