中文摘要：

在成都平原选取了2个镉污染程度不同的区域，测定了污染区内稻米样本中的Cd、Zn质量分数，分析了这些元素含量随污染程度的变化。探讨了农民就地消费稻米的安全性。结果表明，中度（Ⅲ类土）、重度（超Ⅲ类土）Cd污染区稻米Cd质量分数超标严重，超标率分别达75％和1000，而且重度污染区稻米中的Cd含量是中度污染区的近5倍，但Zn含量差异很小，表明随着土壤Cd含量的增加，会加剧稻米Cd累积和Zn的相对缺乏，从而进一步降低食品的安全性；中度Cd污染区65％、重度Cd污染区92％的稻米样品Cd／Zn比值超过了食物Cd／Zn的健康临界值0．015。分别参照WHO和USEPA推荐的成人RFD（Cd）值和当地居民习惯食物消费结构，分析表明对于农民就地消费稻米来说均存在较大程度的潜在Cd暴露风险，特别是重度污染区。因此，对于成都平原Cd污染区，研究相应的控制Cd污染技术并采取适宜的膳食结构做调节，来确保每日饮食中Cd的安全含量显得尤为迫切。

英文摘要：

The paper selected two zones of different cadmium pollution degrees in the Chengdu plain to measure the contents of Cd and Zn in rice samples ,and analyzed the change of contents of these elements with the pollution degree to discuss the potential health risk by food exposure to these rice grains for subsistence-diet farmers. Results show that the content of Cd in rice is over standard seriously in the moderate （Class Ⅲsoil）and severe （super class Ⅲsoil） pollution zone of Cd , in which the excessive rate reaches 75% and 100%,and the content of Cd in rice sampled from the severely polluted area is nearly 5 times higher than that in the moderate pollution area. The difference of Zn content is very small, indicating that the increase of Cd＇s concentration in soil would aggravate Cd accumulation and the relative lack of Zn in rice, thus further reducing the safety of food. The Cd/Zn of the 65% rice samples in the moderate Cd pol- lution zone exceeds the health threshold （ 0. 015）, and the ratio of the severely polluted area of Cd reaches 92%. With reference to the WHO and USEPA recommends adult RFD （Cd） and local residents food consumption structure respectively, this research suggests that there is potential Cd exposure risk, especially in the severe pollution area and for farmers who consume their own rice. Therefore, studying the technology of controlling Cd pollution and adjusting the dietary structure for the Cd pollution zone of the Chengdu plain is particularly urgent to ensure the safety of Cd in food.