Effect of sulfur and sulfur-iron modified biochar on cadmium availability and transfer in the soil–rice system

Manikandan RAJENDRAN, Lizheng SHI, Chuan WU, Wai Chin LI, Wenhui AN, Ziyu LIU, Shengguo XUE

Research output: Contribution to journalArticle

Abstract

Cadmium (Cd) contamination in paddy soils has aroused global concern. Sulfur modified biochar (BC) could combine the benefits of BC and S for Cd remediation. However, no information is available on the impact of sulfur modified biochar on Cd phytoavailability in paddy soils. In this study, a pot experiment was conducted to investigate the effect of sulfur modified biochar (S-BC) and sulfur and iron (Fe) modified biochar (S-Fe BC) on Cd mobility and Cd transfer in the soil-rice system. The application of S-BC and S-Fe BC effectively reduced pore water Cd in the rhizosphere and non-rhizosphere pore water throughout the rice growth stages. S-BC and S-Fe BC addition increased the total chlorophyll content, as well as the root, shoot and grain biomasses of rice. Furthermore, S-BC and S-Fe BC amendments greatly increase the formation of Fe plaque on rice root surface, thus decreasing Cd accumulation in different rice tissues. In particular, S-Fe BC supplementation significantly reduced the Cd concentration in rice grains to 0.018 mg kg⁻¹ in Cd-contaminated soil, which was lower than the China National standard for food contamination limit (0.2 mg kg⁻¹ Cd). Sequential extraction results showed that S-BC and S-Fe BC can promote the transfer of exchangeable Cd to Fe-Mn oxide, organic and residual bound forms which reduce Cd in paddy soils. Thus, the amendment of S-Fe BC to Cd-contaminated paddy soil is an effective strategy to decrease Cd accumulation in rice grains and thereby protect public health. Copyright © 2019 Elsevier Ltd. All rights reserved.
LanguageEnglish
Pages314-322
JournalChemosphere
Volume222
Early online dateJan 2019
DOIs
Publication statusE-pub ahead of print - Jan 2019

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Cadmium
Sulfur
cadmium
Soil
rice
Iron
sulfur
Availability
Soils
iron
soil
biochar
Oryza
effect
porewater
Contamination
Food Contamination
Rhizosphere
Public health
Chlorophyll

Citation

Rajendran, M., Shi, L., Wu, C., Li, W., An, W., Liu, Z., & Xue, S. (2019). Effect of sulfur and sulfur-iron modified biochar on cadmium availability and transfer in the soil–rice system. Chemosphere, 222, 314-322. doi: 10.1016/j.chemosphere.2019.01.149

Keywords

  • Biochar
  • Sulfur and iron modified biochar
  • Cadmium
  • Iron plaque
  • Oryza sativa L