在海南岛中部市县采集了8种蔬菜及其产地酸性土壤样品,采用连续浸提法分析土壤样品中Pb、Cd、Cr元素的水溶态、离子交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态、残渣态以及全量态等的含量,同时测定了对应蔬菜样本中Pb、Cd、Cr的含量,探讨酸性土壤Pb、Cd、Cr兀素的形态分析方法、分布规律及对蔬菜含量的影响.结果表明:Pb、Cd、Cr元素形态分析结果的符合率分别为107％、94％和81％.3元素各形态含量占全量的百分比大小顺序分别为:Pb元素的残渣态＞铁锰氧化物结合态＞有机物结合态＞碳酸盐结合态＞离子交换态＞水溶态:Cd元素的碳酸盐结合态＞残渣态＞离子交换态＞水溶态＞有机物结合态＞铁锰氧化物结合态;Cr元素的残渣态＞有机物结合态＞水溶态＞铁锰氧化物结合态＞离子交换态＞碳酸盐结合态.土壤中有70％以上的Pb、Cr离子处于被固定的状态(即残渣态),不容易被植物吸收,而有70％以上的Cd离子处于活化状态,容易被植物吸收,说明Cd元素是蔬菜无公害安全质量生产中重要的风险控制指标.%Samples of 8 species of vegetables and acid soils of corresponding production areas were collected in cities and counties in middle Hainan Island, and the contents of Pb, Cd and Cr in water soluble form, ion exchange form, carbonate bounded form, iron-manganese oxides bounded form, organic bounded form, residual form as well as total content form, etc. In soil samples were analyzed by sequential extraction procedures. Meanwhile, the contents of Pb, Cd and Cr in the relevant vegetable samples were measured to probe into the analysis method and distribution pattern for Pb, Cd and Cr in different forms in acid soils and their impacts on vegetable contents. The result suggests that the coincidence rates of Pb, Cd and Cr was 107%, 94% and 81%, respectively. The percentages (as for contents) of each form in the total content in a descending order are as follows: residual form, iron-manganese oxides bounded form, organic bounded form, carbonate bounded form, ion exchange form, water soluble form for Pb; carbonate bounded form, residual form, ion exchange form, water soluble form, organic bounded form, iron-manganese oxides bounded form for Cd; residual form, organic bounded form, water soluble form, iron-manganese oxides bounded form, ion exchange form, carbonate bounded form for Cr. Above 70% of Pb and Cr ions in the soil were under stationary state (I.e. Residual form) and difficult to be absorbed by vegetables, while above 70% of Cd ions were under activated state and easy to be absorbed by vegetables, indicating that Cd was an important risk control index in safe and high-quality production of non-pollution vegetables.
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