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Screening of amendments for the remediation of cadmium-polluted protected agriculture soil
Received:March 07, 2018  
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KeyWord:vegetable field;cadmium;immobilizing amendments;bioavailability
Author NameAffiliationE-mail
WANG Yun-li College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
SHI Yao-peng College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
ZHAO Wen-hao College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
LI Ling yi College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
QIAO Jian-chen College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
WANG Yu-wei College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
LIANG Shu-xuan College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China  
LIU Wei College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China auhlw80@126.com 
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Abstract:
      Soil is an important carrier of the natural environment and agricultural production upon which mankind depends. In April 2014, a survey bulletin of soil pollution in China reported that the exceeding standard rate of Cd reached 7.0%, ranking first in the list of inorganic pollutants. Cd is one of the most toxic heavy metal elements, and has a strong chemical activity in the soil and long-lasting toxicity. So in view of the increasing seriousness of heavy metal pollution and risks of agricultural product accumulation in farmland, the effect of different application ratios of carbon-based, phosphorus-based, silicate, clay mineral and other materials, and combined phosphorus-carbon-based passivation materials in repairing cadmium polluted soil and plant growth were studied. The results showed that the application of biochar, hydroxyapatite, montmorillonite, and other materials can significantly reduce the bioavailable cadmium content in soil. Among these materials, hydroxyapatite and biochar significantly decreased the bioavailable cadmium content in soil, which decreased by 46.52%~58.11%. Compared to the control, the application of all passivating materials inhibited the accumulation of cadmium in plants and transfer from the roots to the edible parts. Compared to the control treatment, the Cd content in the ground parts of rapeseed was reduced by 3.9%~51.2%, which is lower than that of the GB 2762-2016 National Food Safety Standard. Therefore straw biochar, hydroxyapatite, montmorillonite, and other materials could effectively reduce the bioavailability of Cd. Considering the production cost and material source, it is recommended that hydroxyapatite(225 kg·hm-2) compounded with 0.6% biochar be used as a combination of preferred materials. Additionally, there was a significant positive correlation between the electrical conductivity(EC) and available Cd content in soil. It was also identified that the application of passivating materials could be a feasible method of decreasing the bioavailability of cadmium in heavy metal-contaminated soil for ensuring safe production in vegetable fields.