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| Effects of water-retaining agents and ryegrass on the transformation of Pb into different forms in soil |
| Received:February 16, 2017 |
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| KeyWord:soil contamination;lead;water-retaining agent;ryegrass |
| Author Name | Affiliation | E-mail | | HU Wei | School of Environment Science and Engineering, Yangzhou University, Yangzhou 225127, China | | | QIN Duan-duan | School of Environment Science and Engineering, Yangzhou University, Yangzhou 225127, China | | | LI Yu-he | School of Environment Science and Engineering, Yangzhou University, Yangzhou 225127, China | | | FANG Yu-jing | School of Environment Science and Engineering, Yangzhou University, Yangzhou 225127, China | | | WANG Xiao-zhi | School of Environment Science and Engineering, Yangzhou University, Yangzhou 225127, China
Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210095, China | | | FENG Ke | School of Environment Science and Engineering, Yangzhou University, Yangzhou 225127, China
Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210095, China | fengke@yzu.edu.cn |
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| Abstract: |
| Heavy metal(HM) pollution in soil is an important environmental problem with respect to food security. Water-retaining agents(WRAs) have recently been used to remediate heavy metal contaminated soil. However, the mechanisms of HM remediation using WRAs have not been well documented. The purpose of this study was to investigate the effects of WRAs on the distribution and morphology of lead(Pb) in soil and to identify the possible mechanisms associated with reduced Pb uptake by plants. To achieve this, Pb-loaded WRAs were characterized using scanning electron microscopy(SEM) to confirm the elemental distribution of Pb on WRAs. A pot experiment with ryegrass(Lolium perenne L.)(0% WRA, 0.2% WRA, ryegrass, and 0.2% WRA + ryegrass) was then carried out to determine Pb uptake and accumulation in aboveground plant tissues. The results indicated that WRAs have good Pb sorption capacity. Pb was mainly immobilized by chelation and complexation with WRAs, and to a considerably lower extent by ion exchange. The pot experiment revealed that soil Pb tends to be mobilized by plant roots, while WRAs can immobilize Pb by transforming it to less soluble species. The combined effects of WRAs and ryegrass roots can induce the release of residual Pb in soil, but much of the released Pb can be quickly sorbed by WRAs. This contributes to a reduction in Pb content in aboveground plant tissues. |
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