土壤碘环境地球化学迁移的^(125)I示踪

Geochemistry Migration of Environmental Iodine in Soil

应用125I示踪技术,在模拟条件下,通过淋溶试验和青菜吸收碘实验,研究了土壤碘的环境地球化学迁移特征及其影响因素,确定了土壤碘转移的定量模式。结果表明,土壤碘(125I)的迁移、挥发和被淋溶的数量与土壤质地有关,淋溶液的酸碱度对土壤碘的流失有显著影响;青菜根系能很快吸收土壤中的125I,并转运至茎叶部分,青菜各部分对125I的富集能力(富集系数)由强到弱的顺序为根、茎、叶柄和叶;土壤保存的碘含量越高,越有利于作物对碘的吸收。这些结果为提高作物吸收碘的效率,进而开辟生产化防治碘缺乏病(IDD)的新途径提供依据。

The environmental and biogeochemical migration of iodine in soil and its effect factors were studied by the ^125I tracer and experiments of leach and absorption by Chinese cabbage to iodine under simulated condition. The quantitative model of iodine in soil transfer were determined. The results showed that the quantities of transfered, volatilized, leached of ^125I in soil had relationship with the texture of soils, and pH of leachate had an important influence on iodine being washed away from soil. ^125I in soil could be taken up rapidly by the Chinese cabbage roots and most of them were transported to the stem and leaf. The 125I enrichment capacity in different parts of Chinese cabbage were ranked by root 〉stem〉petiole〉leaf. The more of ^125I was preserved by soil, the more of 125I was absorbed by the plants. These results provided important scientific basis for preserving iodine in soil and enhancing efficiency of plants absording iodine.