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Effects of plant pond and constructed wetland system on irrigation water purification and rice cadmium control |
Received:September 25, 2018 |
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KeyWord:plant pond;farmland irrigation water;cadmium;wetland plant;rice;atmospheric dry and wet deposition |
Author Name | Affiliation | E-mail | LIU Shou-tao | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | | HE Zhong-xiang | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | | XU Meng | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | | LI Dan-yang | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | | LUO Hai-yan | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | | LIU Xiao-li | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | | TIE Bai-qing | College of Resources and Environment of Hunan Agricultural University, Changsha 410128, China The Engineering Technology Research Center of Water Pollution Purification of Irrigation Water Source, Hunan Province, Changsha 410128, China Key Laboratory of Southern Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture, Changsha 410128, China | tiebq@qq.com |
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Abstract: |
To reduce the input of cadmium (Cd) into farmland with irrigation water and reduce Cd pollution in farmland and rice content, a field experiment was carried out to evaluate the effects of a three-level constructed wetland planted with Pontederia cordata, Myriophyllum verticillatum, and Hydrilla verticillata on Cd uptake ability when Cd exceeded standard irrigation water in amining area (the average Cd concentration was ≈6.65 μg·L-1). The effects of dry and wet deposition flux on system purification were also analyzed. The results showed that the three aquatic plants had good removal ability of Cd, and total and soluble Cd concentrations in the irrigation water decreased significantly after wetland treatment. The average removal rate of total Cd in the system was 70% and soluble Cd was 91%; therefore, there was less Cd polluted water flowing into the farmland. The Cd concentration in the wetland inflow fluctuated with rainfall; however, the removal ability of Cd in the wetland system was not affected. Rainfall was linearly negatively correlated with dry sedimentation and linearly positively correlated with wet sedimentation Cd content. During the observation period, the total input of Cd in the plant pond system was 428.46 g, whereas the dry and wet deposition fluxes were 20.52 g and 57.60 g, respectively, and the Cd retained by the wetland system accounted for 87.9% of the total input. Dry and wet deposition are sources of Cd input, and they have no significant effects on the operation of the wetland. Under normal wetland operation, compared with the rice in the untreated irrigated area, the Cd content in rice roots, stem sheaths, leaves, rice husks, and brown rice in the irrigated area decreased by 5.96, 3.83, 2.42, 0.40 mg·kg-1, and 0.12 mg·kg-1, respectively. The research results provide scientific reference and data support for Cd pollution irrigation water purification, reduction of farmland heavy metal input, and food safety production in typical mining areas. |
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