Simultaneous stimulation of arsenic methylation and inhibition of cadmium bioaccumulation in rice grain using zero valent iron and alternate wetting and drying water management

Angstone Thembachako Mlangeni, Magali Perez, Andrea Raab, Eva M. Krupp, Gareth J. Norton, Joerg Feldmann*

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)


Studies aiming to limit bioaccumulation of arsenic (As) and cadmium (Cd) in rice grain has attracted global attention. In this study, simultaneous impact of zero valent iron (Fe⁰) and various water management regimes (continuous flooding (CF), alternate wetting and drying (AWD) and low water (LW)) on rice grain yield (GYM) and bioaccumulation of As and Cd in unpolished rice grain (URG) were investigated. Compared to respective control treatments, Fe⁰ significantly reduced GYM under LW by 32% (p <0.001) and significantly increased GYM under AWD by 24% (p = 0.009; F = 5.9) but had no significant effect on GYM under CF water management regime (p > 0.05). The grain harvest index was significantly higher in Fe⁰ amended rice under AWD (67%; p <0.001) and CF (35%; p = 0.001) compared to those without Fe⁰ amendment. Fe⁰ significantly reduced tAs in URG under LW by 32% (p <0.017) and significantly increased tAs in URG under AWD by 37% (p = 0.007) but had no significant effect on tAs in URG under CF (p > 0.05). The Cd concentrations were significantly reduced by 51% (p = 0.002) and 61% (p <0.003) in URG under LW and AWD respectively compared to the respective control treatments. The Dimethylarsinic acid (DMA) in unpolished rice (URG) under AWD(+Fe⁰) was significantly higher (p <0.01; F = 11.3) compared to that accumulated in URG under AWD(-Fe°). Despite increasing As accumulation in AWD water management, simultaneous use of AWD water management and Fe° increased grain yield, enhanced accumulation of less toxic methylated As in rice grains and accumulated low Cd concentrations comparable to that attainable with CF water management indicating that simultaneous use AWD and Fe° can be effective in controlling Cd accumulation in paddies highly contaminated with Cd.
Original languageEnglish
Article number134696
Number of pages13
JournalScience of the Total Environment
Early online date23 Nov 2019
Publication statusPublished - 1 Apr 2020



  • Arsenic
  • Cadmium
  • Rice cultivars
  • Zero valent iron (Fe°)
  • Faya cv
  • Continuous flooding
  • Alternate wetting and drying
  • Low water
  • Zero valent iron (Fe-o)

ASJC Scopus subject areas

  • Pollution
  • Waste Management and Disposal
  • Environmental Engineering
  • Environmental Chemistry

Cite this