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| DOI：10.13522/j.cnki.ggps.2019023 |
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| Effect of Plant Pond and Constructed Wetland System on Irrigation Water Purification and Rice Cadmium Control |
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LIU Shoutao, YANG Ruijia, HE Zhongxiang, PENG Ou,LIU Yuling, DONG Sijun, PENG Jing, LIU Xiaoli, TIE Baiqing
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1. College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China; 2. The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Changsha 410128, China; 3. Key Laboratory of Southern Original Agro-environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China)
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| Abstract: |
| Irrigation of heavy metals exceeding water in southern China has become the most important source of heavy metal input in farmland. 【Objective】It has great practical to control heavy metal Cd pollution from irrigation water in southern China. 【Method】In this study, three wetland plants, barracuda, Myriophyllum sp., and Hydrilla verticillata, were used to build a grit chamber + ecological pond + surface flow wetland + adsorption pool system to explore the changes of Cd content and organic matter in the sediment of the wetland systems. The trend of Cd concentration in plant tissues and the BF, TF coefficient were also studied. 【Result】The Cd content in the sediment of the wetland system had a decreasing trend with the flow direction. The concentration of Cd at each sampling sites increased with sampling over time, and the Cd content in the sediment ranged from 1.15 to 38.58 mg/kg. The organic matter content of the sediment gradually decreased with the flow direction and the highest decrease was 13.9 g/kg. Among the three wetland plants, the highest Cd content in the belowground and aboveground parts of the barracuda was 125.88 mg/kg and 9.16 mg/kg. The highest concentrations in the foxtail algae and Hydrilla verticillata reached 32.55 mg/kg, 6.94 mg/kg, respectively.The BF and TF coefficient of Barracuda were 8.24~34.96 and 0.036~0.176, respectively, indicating that most of the Cd in the barracuda was accumulated at roots rather than transport. 【Conclusion】Among the three plants, the barracuda has high Cd purification potential in farmland irrigation water. The research results can provide data support for Cd polluted irrigation water purification in southern China. |
| Key words: Ecological pond; organic matter; cadmium; wetland plant; enrichment factor; transport coefficient; constructed wetland |
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