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Principle and technique of arsenic and cadmium pollution control in paddy field
Received:May 02, 2018  
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KeyWord:paddy field;cadmium;arsenic;iron cycle;physiological barrier;passivation
Author NameAffiliationE-mail
YU Huan-yun Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China  
CUI Jiang-hu Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China  
QIAO Jiang-tao Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China  
LIU Chuan-ping Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China  
LI Fang-bai Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China cefbli@soil.gd.cn 
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Abstract:
      Control of heavy metal pollution of farmland soil in China has become a major national demand; compared to other cereals, rice is particularly susceptible to heavy metal accumulation with the highest proportion exceedling the safety standard; cadmium/arsenic pollution of paddy field is the emphasis and difficulty for control of heavy metal pollution in farmland. Aiming for the safety of agricultural products, control technique which directionally regulates activities of heavy metals and inhibits their transports provides a new thought for control of heavy metal pollution and is of great significance to solve the problem of remediation of heavy metal pollution in paddy field. Iron is the most important active element in paddy field. The iron cycle in paddy field is the hub connecting the cycling of nutrients and cadmium/arsenic behaviors; it can reduce the migration activities of cadmium/arsenic from soil to rice roots through regulating the coupling processes of iron and carbon/nitrogen cycle and thus decrease accumulations of cadmium/arsenic in rice plants. Silicon and selenium and other nutrients are closely related to the uptakes and transports of cadmium and arsenic in rice. Exogenous application of silicon/selenium nutrients can reduce the expression levels of genes accociated with absorptions and transports of cadmium/arsenic in rice and increase the gene expression of detoxification, thereby inhibiting transports of cadmium/arsenic from rice roots to grains. Based on the above principles, the silicon/selenium nutrient-regulated physiological barrier technology and the iron cycling-regulated passivation technology were developed, and corresponding products were also developed. The results of the field experiments showed that the physiological barrier and soil passivation techniques applied alone or in combination can effectively reduce the cadmium/arsenic contents in rice and thus increase rice safety. These technologies have broad application prospects.