14种蔬菜对土壤Cd和Pb富集能力的估算

Estimation of the accumulation of cadmium and lead by 14 vegetables from soils

以田间采集的蔬菜和土壤的分析数据为基础,探讨了14种蔬菜对土壤Cd和Pb的富集能力及其估算方法.结果表明,土壤—蔬菜Cd或Pb的转移系数(全量基或DTPA基)随土壤Cd或Pb量(全量或DTPA有效量)的升高而降低.以DTPA提取的有效Cd或Pb为基础计算的转移系数比以土壤Cd或Pb全量为基础的转移系数在衡量蔬菜对土壤Cd或Pb的吸收富集能力方面更具合理性.一种作物对土壤Cd或Pb的代表性转移系数应该根据转移系数与土壤Cd或Pb之间的回归方程,在特定的土壤含量点上估算,而不应简单地用平均数或中位值表示.本试验在DTPA有效Cd含量为0.1 mg.kg-1和DTPA有效Pb含量为25 mg.kg-1的点上估算了Cd、Pb的转移系数.Cd向各蔬菜的转移系数(DTPA基0.1)为0.01-0.38,Pb向各蔬菜的转移系数(DTPA基25)为0.0005-0.0063.空心菜对土壤Cd、Pb的富集能力很强,葫芦很弱.空心菜对土壤Cd、Pb的富集能力分别是葫芦的38和12倍.

Accumulation of 14 vegetables of Cd and Pb from soils and its evaluation method were studied based on the data of fiddcollected soil and vegetable samples. The results showed that the transfer factors based on both total （ TFtotal ） and those based on DTPA-extractable （ TFDTPA ） Cd and Pb in the soils decreased with the increase of soil Cd or Pb （ beth total and DTPA-extractable）. The TFDTPA is better than TFtotal in evaluating the accumulation ahility of the vegetables for Cd and Pb. The representative transfer factor for a given crop-Cd （ or Ph） system should be evaluated based on the regression equations between the transfer factors and the corresponding soft Cd and Ph and at a given soft Cd or Ph concentration. Arthritic mean, geographic mean and median of a group of data are not good indicators for the accumulation for a crop-Cd （ or Pb） system. The representative TFDTPA values of the vegetables for Cd and Ph were evaluated at DTPA-extractable Cd = 0.1 mg·kg^-1 and DTPA-extractable Ph = 25 mg·kg^-1, respectively. The TFDTPA values of the vegetables for Cd varied from 0.01 to 0.38, and those for Ph varied from 0.0005 to 0.0063. It was shown that water spinach was the strogest in accumulating Cd and Ph, whereas bottle gourd was the weakest. The TFDTPA 0.1 values of water spinach for Cd and Ph were 38 and 12 times higher than those of bettle gourd.