【摘要】 通过温室盆栽试验,研究了长江三角洲地区3种典型土壤类型中Pb在土壤-青菜系统中的转运及Pb污染对青菜Pb含量、土壤硝化细菌和微生物多样性的影响。结果表明,Pb在土壤-青菜系统中的转运是非线性的。青菜地上部Pb含量与0.43mol/LHNO3和0.05mol/LEDTA提取态Pb显著相关,青菜Pb含量与0.01mol/LCaCl2提取态Pb相关性不显著。研究认为,0.43mol/LHNO3和0.05mol/LEDTA提取态Pb可成为土壤Pb植物有效性的评价指标。青紫泥和滩潮土中添加Pb浓度为125~625mg/kg,对土壤硝化细菌数量和土壤微生物多样性影响不明显。以基于人体健康风险、国家食品卫生标准和植物毒性为依据,计算得出的总Pb临界浓度分别为:黄泥砂土140、59和12263mg/kg,青紫泥790、292和13902mg/kg,滩潮土1266、418和30422mg/kg。更多还原

【Abstract】 In the present research, the partition of Pb in soil-crop system and effects of soil Pb contamination on microbial ecology of three different soils were investigated in greenhouse pot trial. The results showed that the metal content in Brassica chinensis L. could be described by a nonlinear relationship with soil metal. Both 0.43 mol/L HNO3 and 0.05 mol/L EDTA extractable Pb in soil were significantly correlated with the content in Brassica chinensis L. shoots. In contrast, Pb content in Brassica chinensis L. shoots had no significant correlation with 0.01 mol/L CaCl2 extractable Pb in soils. Considering the simplicity and low cost of 0.43 mol/L HNO3 or 0.05 mol/L EDTA extraction, the extraction solution could serve as an alternative method for assessment of phytoavailability of soil Pb to plants. Soil Pb contamination had no effect on nitrifying bacteria and soil microbial diversity. Critical limit of Pb based on human health risk, national food criterion or plant toxicity were 140、59 and 12263 mg/kg for Fe-accumulic Gleyic Stagnic Anthrosols, 790、292 and 13902 mg/kg for Typic Gleyic Stagnic Anthrosols, 1266、418 and 30422 mg/kg for Lithic Ochri-Aquic Cambosols, respectively.更多还原