1. Combining biochar and zerovalent iron (BZVI) as a paddy field soil amendment for heavy cadmium (Cd) contamination decreases Cd but increases zinc and iron concentrations in rice grains: a field-scale evaluation.
- Author
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Khum-in, Vinita, Suk-in, Jirapon, In-ai, Papop, Piaowan, Kitsanateen, Phaimisap, Yanapat, Supanpaiboon, Wisa, and Phenrat, Tanapon
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BROWN rice , *SOIL amendments , *PADDY fields , *RICE , *GRAIN , *CADMIUM , *SOIL restoration - Abstract
• A paddy field in Thailand contaminated with Cd (41.02 mg kg−1) was restored. • BZVI decreased Cd accumulation in rice grains by 83 %. • BZVI as soil amendment enriched Fe and Zn accumulation in rice grains by 10 %. • ZVI corrosion enhanced by biochar is the key to BZVI success. • This technique is suitable for community-driven soil restoration. Consuming rice grown in contaminated soil that has an elevated level of cadmium (Cd) is a health risk. This study revealed that using a combination of biochar and zerovalent iron (BZVI) reduces the concentration of Cd and enhances that of the essential elements zinc (Zn) and iron (Fe) in rice. The Cd concentration in brown rice grain cultivated in an untreated paddy was 0.84 ± 0.20 mg kg−1, double the acceptable level (0.4 mg kg−1). Soil amendment with BZVI successfully decreased Cd in brown rice by 83 % compared to the untreated field presumably due to the Cd sorption on biochar (BC) and enhanced ZVI corrosion by-products while ZVI and BC alone achieved only 40 % and 74 % reduction, respectively. Moreover, while using ZVI or BC alone decreased Fe in rice grain by 8–14 %, BZVI enhanced the Fe concentrations in rice grain by 11 % because of Fe2+/Fe3+ release from BC-enhanced ZVI corrosion. Similarly, the presence of BC in BZVI enhanced Zn accumulation in rice grain by 8% due to competitive sorption of Cd2+ on BZVI, which may desorb Zn2+, promoting Zn translocation to rice. Using ZVI alone decreased Zn in rice by 19 %. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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