Coconut-fiber biochar reduced the bioavailability of lead but increased its translocation rate in rice plants: Elucidation of immobilization mechanisms and significance of iron plaque barrier on roots using spectroscopic techniques

Publication date: Available online 16 January 2020Source: Journal of Hazardous MaterialsAuthor(s): Jianhong Li, Shan-Li Wang, Jingmin Zhang, Lirong Zheng, Dongliang Chen, Zhipeng Wu, Sabry M. Shaheen, Jörg Rinklebe, Yong Sik Ok, Hailong Wang, Weidong WuAbstractCoconut-fiber biochar (CFB) was applied at 3% (w/w) to two soils spiked with 250, 2500, 5000 mg kg−1 of lead (Pb), respectively, aiming to explore the effects of CFB and the significance of iron (Fe) plaque on rice roots on the accumulation and translocation of Pb in rice plants using micro-X-ray fluorescence and X-ray absorption spectroscopies. The CFB amendment resulted in a significant decrease in the EDTA-extractable Pb availability in the soils, which might be attributed to the increased amounts of Pb-loaded humic acid and Pb3(PO4)2 formed in the soils. Consequently, the addition of CFB caused a significant decrease in Pb concentrations of the brown rice harvested from the CFB-amended soils under all Pb levels by 14% - 47%, as compared to those from the unamended soils. Therefore, CFB could be used as an immobilizing agent for Pb in contaminated soils. However, CFB application significantly inhibited the formation of Fe/Mn plaques on rice roots and reduced its interception effect on Pb uptake, which consequently increased the Pb translocation rate from root to shoot. Therefore, the increased translocation rate of Pb in rice plants by CFB should not be ignored when CFB is applied to remediate Pb-contaminated ...
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research