施用白垩和膨润土对降低作物吸收放射性锶和铈的有效性

采用模拟污染物的同位素示踪技术研究了在土壤中施用白垩和在田表水中撒洒膨润土对降低作物 (尤其是作物的食用部分 )中89Sr和14 1Ce积累的效应。结果表明 :白垩能有效降低黑麦草、青菜对89Sr的吸收 ,当白垩施用量为 2 0g kg时 ,青菜对89Sr吸收降低率达 77 6% ,黑麦草也能降低 3 5 2 % ,土壤中白垩的引入量与黑麦草、青菜中89Sr的比活率呈显著性线性负相关 ;在田表水中的撒洒适量膨润土可以使田表水、稻壳和糙米中的14 1Ce比活度有所下降 ,从而减少稻谷对14 1Ce的积累 ,但未能改变稻根、稻草对14 1Ce的吸收和积累 ,14 1Ce在水稻土中的纵向分布均与土层深度呈单项指数负相关。

VALIDITY OF CHALK AND BENTONITE APPLICATION IN SOIL AND WATER ON REDUCING THE ABSORPTION OF RADIO-STRONTIUM AND RADIO-CERIUM BY CROP

Effects of the chalk and bentonite application in soil and surface water respectively on reducing the absorption of 89 Sr and 141 Ce by crop(especially in the edible part of crop)were studied by using isotopetracer techniques. The results showed that the specific activity of 89 Sr in the ryegrass and Chinese cabbage could be decreased significantly by chalk application in the soil. The reduced ratio of 89 Sr absorption of Chinese cabbage and ryegrass reached 77 7% and 35 2% respectively with the chalk application of 20g/kg soil. The specific activity of 89 Sr in ryegrass and Chinese cabbage followed obvious negative linear correlation with the quantity of application chalk in the soil. The specific activity of 141 Ce in surface water, chaff and brown rice decreased by application bentonite in the surface water, which led to the lower accumulation of 141 Ce in paddy. However, the absorption and accumulation of 141 Ce in root and straw could not be changed. The specific activity of 141 Ce in soil followed a negative exponential relation with depth of soil profile.