采集张士灌区下游彰驿站镇水田土壤及水稻植株样品,测定土壤和水稻植株各部位中总镉浓度及土壤中不同形态镉浓度,采用单因子污染指数法分析了水田土壤及糙米的镉污染现状,并根据镉在水稻中的迁移系数、富集系数、土壤中不同形态镉对植株的贡献率及镉形态与土壤理化性质的关系探讨了影响植株镉吸收因素。结果表明:采样区土壤镉含量在0.47~2.49 mg·kg-1,均已超过国家土壤环境质量二级标准(GB 15618—1995),且超过当地背景值1.47~12.11倍;土壤中镉形态特征分布为残渣态>弱酸提取态>可还原态>可氧化态;水稻植株各器官镉含量分布趋势为根>茎>叶>糙米;有41.6%的糙米样品超过国家相应的食用标准,目前多以轻度污染为主;水稻对镉的富集能力、镉在水稻植株中的迁移能力及土壤中镉的形态分布是影响水稻吸收土壤中镉的重要因素,其中土壤中弱酸提取态和可还原态对水稻植株镉的吸收贡献率最大,且二者与土壤pH和CEC之间的相关性达到显著性水平。 Soil samples of paddy soils and rice plants from Changziyi town in the downstream of Zhangshi Irrigation District were collected. Total cadmium concentrations in different parts of soils and rice plants and cadmium concentrations in different soil samples were determined. The status of cadmium pollution in paddy soils and brown rice was analyzed by single factor pollution index The Cd uptake by plants was also investigated based on their relationship with the migration coefficient and enrichment coefficient of Cd in rice, the contribution rate of Cd to the plants and the relationship between Cd speciation and soil physical and chemical properties. The results showed that the contents of cadmium in the soil samples ranged from 0.47 to 2.49 mg · kg-1, both of which exceeded the national secondary standard of soil environmental quality (GB 15618-1995) and exceeded the local background value of 1.47-12.11 times. The results showed that the distribution of Cd in different organs of rice plants was root> stem> leaf> brown rice; 41.6% of brown rice samples exceeded the corresponding national food standards, Mild Cd uptake, Cd uptake ability in rice, Migration of Cd in rice plants, and Cd speciation in soil were the important factors affecting the Cd uptake by soils. Among them, the weak acid extractables and reducible The contribution of cadmium to rice plants was the largest, and the correlation between them and soil pH and CEC reached the significant level.