大宝山矿周边污染土壤重金属生物有效性评估

 分析了6种单一提取剂HCl、DTPA、CaCl₂、NH₄ NO₃、MgCl₂、去离子水对大宝山矿周边上坝村受污染菜地（生菜、芥菜、蕹菜）土壤中Pb、Zn、Cu和Cd生物可利用性的指示能力。结果表明：3种菜地的HCl、DTPA提取态的Pb，CaCl₂、NH₄NO₃和MgCl₂提取态的Zn，CaCl₂提取态的Cd可以比较好地反映金属的生物有效性；而3种蔬菜中的Cu与土壤6种提取态的Cu均没有显著的相关性。土壤样品中铁锰氧化物对Pb、Zn、Cu和Cd的固定作用直接影响该4种重金属的析出，并且Cu、Cd和Pb所受的影响要强于Zn。结果还表明，与地上部分相比蔬菜地下部分的重金属含量能更准确地反映重金属从土壤向植物中的转移。

Bioavailability Assessment of Heavy Metals in the Vicinity of Dabaoshan Mine

In this study, the predictive ability of six extractants (HCl, DTPA, CaCl₂, NH₄ NO₃, MgCl₂ and deionized water) was investigated with respect to bioavailability of Pb, Zn, Cu and Cd in three types of vegetable planted soils, which were collected from Shangba Village near Dabaoshan mine. The results showed that Pb extracted by HCl and DTPA and the Zn extracted by CaCl₂, NH₄NO₃ and MgCl₂ had good correlation with metals concentrations in the three vegatables. Among six extractants, CaCl₂ extractable Cd showed the best correlation with bioavailable Cd.Extracted Cu by all six extractants had no significant correlation with Cu concentrations in vegetables. HCl-and DTPA-extractable Fe and Mn concentrations were very high in soils,which indicated that most of Pb, Zn, Cu, and Cd were tightly bound with these fractions and this might be responsible for low extraction rate. Comparing with Pb, Cu and Cd,Zn was least affected by Fe and Mn oxides. Moreover,the heavy metal concentrations in roots could be more reasonable indices to investigate the transfer from soil than those in shoots.