Iron-Based Nanomaterials Enhance Rice Growth and Limit Grain Arsenic Accumulation via Iron Plaque Formation and...

Area of Science:

• Environmental Science
• Soil Science
• Nanotechnology

Background:

• Arsenic (As) contamination in paddy soils poses risks to rice safety and human health.
• Iron-based nanoparticles (NPs) are explored for their potential in mitigating soil contaminant bioavailability.

Purpose of the Study:

• To evaluate the impact of iron-based NPs (nZVI, Fe2O3 NPs, Fe3O4 NPs) and ionic iron fertilizers on rice growth, arsenic accumulation, and rhizosphere properties.
• To investigate the mechanisms by which iron amendments affect arsenic dynamics and speciation in paddy soil.

Main Methods:

• Short-term (40-day) and life-cycle (128-day) pot experiments with rice.
• Analysis of iron plaque formation, structural characteristics, and physicochemical properties.
• Assessment of arsenic concentrations, iron content in rice grains, and rhizosphere soil microbial gene abundance.

Main Results:

• All iron treatments increased rice grain yield and iron content while reducing arsenic concentration in grains.
• Nanoscale zero-valent iron (nZVI) demonstrated the most significant arsenic mitigation effect.
• Iron NPs altered root-associated iron plaque, increasing crystalline iron oxides and enhancing arsenic-iron colocalization, thereby improving arsenic immobilization.

Conclusions:

• Iron-based nanoparticles, particularly nZVI, are a promising strategy for reducing arsenic exposure risks in contaminated paddy soils.
• Fe NPs enhance arsenic immobilization by modifying iron plaque properties and promoting the transformation of labile arsenic into stable forms in the rhizosphere.