Zinc Fertilizers Modified the Formation and Properties of Iron Plaque and Arsenic Accumulation in Rice (Oryza sativa L.) in a Life Cycle Study

• Published in: Environmental science & technology 2022-06, Vol.56 (12), p.8209-8220
• Main Authors: Wang, Xiaoxuan, Jiang, Jiechao, Dou, Fugen, Li, Xiufen, Sun, Wenjie, Ma, Xingmao
• Format: Article
• Language: English
• Subjects: Accumulation; Arsenic; Cereal crops; Contaminants in Aquatic and Terrestrial Environments; Crop yield; Crystallization; Ferric oxide; Fertilizers; Food safety; Grain; Iron oxides; Life cycles; Nanoparticles; Oryza sativa; Plaques; Rice; Rice fields; Roots; Silicon dioxide; Silicon oxide; Silicon oxides; Soil properties; Speciation; Zinc oxide; Zinc oxides
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.2c01767

This study examined the effect of three forms of zinc fertilizers on arsenic (As) accumulation and speciation in rice tissues over the life cycle of this cereal crop in a paddy soil. The formation and properties of iron plaque on rice roots at the maximum tillering stage and the mature stage were also determined. Elevated As at 5 mg/kg markedly lowered the rice yield by 86%; however, 100 mg/kg Zn fertilizers significantly increased the rice yield by 354–686%, regardless of the Zn form. Interestingly, only Zn2+ significantly lowered the total As in rice grains by 17% to 3.5 mg/kg and As­(III) by 64% to around 0.5 mg/kg. Zinc amendments substantially hindered and, in the case of zinc oxide bulk particles (ZnOBPs), fully prevented the crystallization of iron oxides (Fe3O4 and Fe2O3) and silicon oxide (SiO2) and altered the composition of iron plaques on rice roots. SiO2 was first reported to be a significant component of iron plaque. Overall, ZnOBPs, ZnO nanoparticles, and Zn2+ displayed significant yet distinctive effects on the properties of iron plaque and As accumulation in rice grains, providing a fresh perspective on the potentially unintended consequences of different Zn fertilizers on food safety.