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| Phytoremediation of the soil contaminated by Pb, Cd and secondary salinization with the enhancement of EDTA |
| Received:February 07, 2018 |
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| KeyWord:soil remediation;heavy metal;secondary salinization;halophyte;EDTA |
| Author Name | Affiliation | E-mail | | WANG Yu-han | Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Resources and Environment, Southwest University, Chongqing 400715, China | | | CHEN Dong-yue | Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Resources and Environment, Southwest University, Chongqing 400715, China | | | JIANG Zhi-yong | Department of Environmental and Quality Inspection, Chongqing Chemical Engineering Vocational College, Chongqing 401228, China | | | NIE Wen-han | Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Resources and Environment, Southwest University, Chongqing 400715, China | | | ZHANG Jin-zhong | Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Resources and Environment, Southwest University, Chongqing 400715, China
Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China | jzhzhang@swu.edu.cn |
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| Abstract: |
| In order to remedy the soil contaminated by heavy metals and secondary salinization, the pot experiments were conducted to investigate the removal efficiencies of Pb, Cd and salt anions (NO3-, Cl- and SO42-) by two halophytes with the enhancement of EDTA. The results showed that the addition of EDTA could significantly promote halophytes to absorb and enrich Pb and Cd in the contaminated soils. With the enhancement of 4 mmol·kg-1 EDTA, the removal efficiencies of Pb and Cd were 32.59% and 36.47% by Sedum aizoon L., and those were 22.93% and 29.36% by Suaeda salsa for the moderately polluted soil with Pb and Cd, respectively. For the combined pollution soils with Pb, Cd and salt anions, the removal efficiencies of Pb and Cd in the mildly polluted soil were 41.37% and 47.25% by Sedum aizoon L., and those in the moderately polluted soil were 36.42% and 41.48% by Suaeda salsa, respectively. The removal ability of the three salt anions showed a decreasing order of NO3-, Cl- and SO42- by Sedum aizoon L., whereas that showed little difference by Suaeda salsa. The existence of appropriate amount of salt anions could activate Pb and Cd in the contaminated soil, and increase their mobility and bioavailability, which may promote the halophytes to absorb heavy metals. When the contents of salt anions in the contaminated soil exceeded the tolerance thresholds of the halophytes, excess salinity might reduce the absorption ability of plant to Pb and Cd. In addition, the biomass of Sedum aizoon L. was obviously greater than that of Suaeda salsa, and plant resistance indices indicated that the tolerance ability of Sedum aizoon L. to Pb, Cd and salt anions was much stronger. The combined pollution soil with heavy metals and secondary salinization could be effectively remedied by Sedum aizoon L. with the enhancement of EDTA, and the removal efficiencies of Pb, Cd were 37.87% and 41.61%, and those of NO3-, SO42- and Cl- were 59.22%, 42.11% and 51.65% for the actual pollution soil, respectively. |
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