土壤中植物有效态镉提取方法比较

    Evaluation and Comparison of Phytoavailability of Cadmium in Contaminated Soils by Three Chemical Extraction Procedures

    • 摘要: 通过温室盆栽试验研究了滩潮土、青紫泥田和黄泥砂田中添加镉对青菜镉吸收的影响,评价了人工螯合剂、无机盐和硝酸溶液对污染土壤中镉的浸提性及其植物有效性。结果表明,青菜地上部镉与土壤镉含量呈非线性关系。土壤pH值和碳酸钙含量是影响镉植物有效性的主要因素,青菜对镉的吸收与土壤pH呈显著负相关。在土壤镉含量相同条件下,黄泥砂田、青紫泥田、滩潮土3种土壤中青菜地上部镉含量依次降低。青菜地上部镉含量与0.43mol·L-1HNO3、0.05mol·L-1EDTA和0.01mol·L-1CaCl2提取态镉均呈显著相关(r2=0.73~0.96)。笔者认为,这3种提取剂提取的土壤镉可视为植物有效态镉。

       

      Abstract: Effects of soil Cd contamination on growth of Brassica chinensis in three different soils were investigated through greenhouse pot trial.Chemical fractions of cadmium (extracted by 0.43 mol·L-1 HNO3,0.05 mol·L-1 EDTA and 0.01 mol·L-1 CaCl2) were evaluated by using a single extraction procedure. The results show that the Cd content in the aboveground part of Brassica chinensis had a nonlinear relationship with the metal in soils. It has been found that Cd content in the aboveground part of Brassica chinensis has negative correlation with soil pH values. The Cd mobility was in the order of Fe-accumulic Gleyic Stagnic Anthrosols>Typic Gleyic Stagnic Anthrosols>Lithic Ochri-Aquic Cambosols. 0.43 mol·L-1 HNO3,0.05 mol·L-1 EDTA and 0.01 mol·L-1 CaCl2 extractable Cd were significantly correlated with the Cd content in the aboveground part of Brassica chinensis. Considering the simplicity and low cost of 0.43 mol·L-1 HNO3,0.05 mol·L-1 EDTA or 0.01 mol·L-1 CaCl2 extraction,the extraction solutions could serve as an alternative method for assessment of phytoavailability of soil Cd to plants.

       

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