Effect of Zero-Valent Iron on Arsenic Uptake by Rice (Oryza sativa L.) and its Relationship with Iron, Arsenic, and Phosphorus in Soil and Iron Plaque

摘要

An outdoor pot experiment was conducted to study the control effects of zero-valent iron (Fe-0) on arsenic (As) uptake by rice (Oryza sativaL.) and its relationship with iron (Fe), As, and phosphorus (P) in soil and Fe plaque. The results showed that Fe-0 reduced total and inorganic As in root, husk, and grain but had no significant effect in straw, and almost all contents of As species in rice plant were decreased by Fe-0. Total As contents in root, husk, and grain were decreased (54.8%, 39.9%, 30.1%), while reductions of inorganic As were 59.2%, 30.8%, and 30.3%, respectively. The inorganic As in all issues of rice plant was dominated and higher than 70% of total As. The analysis showed that the main mechanisms of Fe-0 on reduction of As in rice were (i) Fe-0 stabilized the active As in soil, (ii) Fe(0)increased the quantity of Fe plaque that hindered the transport of arsenic in soil to rice plant, and (iii) phosphorus adsorbed on the Fe plaque reduced As into rice root by the competitive mechanism between phosphorus and arsenic.