Application of Silica Nanoparticles Induces Different Effects on Inorganic and Methylated Arsenic Accumulation in Rice Grains: Insights from Arsenic Transformation in Soil

showed a 1-3 orders of magnitude higher abundance than arsenic-reduction/methylation genes, and its abundance significantly increased after both applications. SiNP applications facilitated the release of Fe-bound organic carbon into porewater and promoted bacterial growth and As(III) oxidation, leading to high As(V) availability for rice uptake. Nevertheless, foliar spraying performed better than soil amendment in reducing total arsenic in grains by inhibiting stem/nodes-to-grain translocation. Our findings highlight the microbial arsenic transformation in soil regulated by SiNPs and demonstrate the advantages of foliar spraying in the arsenic-contaminated paddy field.