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

Jianhong Li, Shan Li Wang, Jingmin Zhang, Lirong Zheng, Dongliang Chen, Sabry M. Shaheen, Jörg Rinklebe, Yong Sik Ok, Hailong Wang, Weidong Wu

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Abstract

Coconut-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 paddy soils.

Original languageEnglish
Article number122117
JournalJournal of hazardous materials
Volume389
DOIs
Publication statusPublished - 2020 May 5

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Keywords

  • Biochar amendment
  • Contaminated paddy soil
  • Lead accumulation
  • XAFS
  • XRF

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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