Characterizing the interactions between Cd and Zn with respect to the soil soluble Cd and crop Cd uptake allows the development of risk-based approaches to the performance of grain crops. By means of a three-year survey of 358 rice fields and 206 wheat fields across China, this study investigated the effect of Cd-Zn interactions on the phytoavailability of Cd to rice and wheat. The interactive nature between the Cd:Zn ratio and pH of soil affected crop Cd uptake, and the resulting grain Cd intake risk, were examined by the Free-Ion Activity-based model and probability analysis. In highly acidic rice soils (pH<5.9), soil Zn had no effect on rice Cd uptake, whereas, under near-neutral conditions (pH>5.9), a site-specific influence of soil Zn on grain Cd concentration was found. Soil Zn could inhibit Cd uptake and translocation by the plant in soil-wheat system when the soil Cd:Zn ratio decreased to 0.0083 and lower. Rice grain poses a significant health risk to local consumers due to its high Cd accumulation and its low Zn accumulation. In order to reduce the health risks from dietary Cd to local consumers, approximately 63.9% of the rice fields and 30.5% of the wheat fields require strategies ameliorating soil acidity in rice soils and increasing Zn concentrations in wheat soils.

表征土壤中可溶性Cd和作物Cd吸收方面Cd和Zn之间的相互作用，可以开发出基于风险的谷物作物生产方法。通过对全国358个稻田和206个麦田的三年调查，本研究调查了Cd-Zn交互作用对Cd对水稻和小麦的植物有效性的影响。通过基于自由离子活度的模型和概率分析研究了土壤中镉对土壤镉的吸收与镉，锌比和pH之间的相互作用，以及由此产生的谷物对镉的摄入风险。在高酸性水稻土（pH <5.9）中，土壤锌对水稻Cd的吸收没有影响，而在接近中性条件下（pH> 5.9），土壤锌对籽粒Cd的浓度有特定的影响。当土壤中Cd：Zn的比例降低至0.0083或更低时，土壤Zn可以抑制植物对Cd的吸收和转运。稻米由于其高的Cd积累和低的Zn积累而对当地消费者构成重大健康风险。为了减少饮食中镉对当地消费者的健康风险，大约63.9％的稻田和30.5％的麦田需要采取措施来改善稻田土壤的酸度并增加锌在土壤中的含量。