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| Study on leaching of lead and cadmium in farmland soils by citric acid-enhanced low concentration EDTA in the Chengdu Plain |
| Received:August 10, 2017 |
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| KeyWord:citric acid;EDTA;Pb;Cd;paddy soil;purple soil;composite washing |
| Author Name | Affiliation | E-mail | | YAO Ping | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
Chengdu Academy of Environmental Sciences, Chengdu 610072, China | | | GUO Xin | Chengdu Academy of Environmental Sciences, Chengdu 610072, China | | | WANG Ya-ting | Chengdu Academy of Environmental Sciences, Chengdu 610072, China | | | ZHONG Qin-mei | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | | | ZHANG Shi-rong | College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China | rsz01@163.com | | HE Yu-ting | Chengdu Agricultural Technology Extension Station, Chengdu 610031, China | |
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| Abstract: |
| Heavy metals adversely affect the safety of farmland soils in the Chengdu Plain. In order to determine high-efficiency remediation technology for heavy metals in these soils, this study investigated the removal efficiency of Pb and Cd from paddy and purple soils through different washing methods using citric acid and low concentration ethylenediaminetetraacetic acid(EDTA), and further analyzed the concentrations of organic matter and nutrients in soil. The results showed that the single method using 0.02 mol·L-1 EDTA removed 44.94% of Pb and 88.32% of Cd from paddy soil, and 48.48% of Pb and 71.85% of Cd from purple soil. Similarly, the single method using 0.1 mol·L-1 citric acid removed 24.71% of Pb and 69.38% of Cd from paddy soil, and 33.54% of Pb and 59.77% of Cd from purple soil. Compared with the two single methods, the combined methods of citric acid with low-concentration EDTA had higher metal removal efficiency. In addition, the highest removal efficiency was derived from the washing method using EDTA followed by citric acid. This composited washing method enhanced the removal efficiency of Cd and Pb by 6.07% and 9.67% for paddy soil, respectively, and the same indicators for purple soil by 10.33% and 14.73% more than the single method of EDTA washing. Simultaneously, this washing method also reduced the loss of organic matter and nutrients from soils by over 10% more than the other methods. In summary, the method using EDTA followed by citric acid is the most suitable for the removal of the two heavy metals and for conserving organic matter and nutrients among all the studied washing methods. |
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