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Remediation and persistent stability effects of sepiolite on cadmium-contaminated paddy soil
Received:June 28, 2021  
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KeyWord:rice;cadmium;sepiolite;immobilization remediation;persistence
Author NameAffiliationE-mail
PEI Nan Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
School of Resource and Environment, Northeast Agricultural University, Harbin 150030, China 
 
LIANG Xuefeng Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China  
QIN Xu Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China  
ZHAO Lijie Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China  
HUANG Qingqing Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China hqcauedu@126.com 
XU Yingming Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China  
SUN Yuebing Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture and Rural Affairs, AgroEnvironmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China  
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Abstract:
      In the present study, a 2-year field experiment was conducted to investigate the immobilization efficiency and remediation stability effects of sepiolite on Cd-contaminated paddy soil. Concentration of Cd in rice grain and available Cd in soil were determined along rice grain quality, soil Cd fractions, and soil enzyme activity. The results showed that sepiolite effectively and persistently immobilized Cd in paddy soils. However, the immobilization efficiency weakened over time. In the first year, sepiolite application significantly reduced the content of Cd in brown grain of early and late rice by approximately 21.0%~79.0% and 63.8%~88.0%, respectively, when compared with the control treatment. In addition, the content of Cd in brown grain of early rice was below the recommended tolerable level(0.20 mg·kg-1) at sepiolite application rates up to 1.00 kg·m-2. The content of Cd in brown grain of late rice was below the recommended tolerable level only when sepiolite application rate was the highest(i.e., 2.00 kg·m-2). In the second year, sepiolite application significantly reduced the Cd content in brown grain of early and late rice by approximately 4.0%~73.5% and 21.4%~81.0%, respectively. Moreover, the Cd content in brown grain of early rice was below 0.20 mg·kg-1 only with the highest sepiolite application rate. Therefore, the results of the 2-year field experiment show the continuous effects of sepiolite on immobilization remediation of Cd-contaminated paddy soil; this could guarantee the safety of produced rice. Nonetheless, the remediation efficiency of sepiolite on Cdcontaminated paddy soil needs to be tracked and monitored during the field remediation process; sepiolite should be reapplied, if necessary, to ensure the persistence of the remediation effect.