Evaluation of the effects of application of iron materials on the accumulation and speciation of arsenic in rice grain grown on uncontaminated soil with relatively high levels of arsenic

•We examined the effect of Fe materials on the arsenic uptake by rice.•Fe materials significantly decreased arsenic species in the soil solution.•Increase in free iron oxide in the soil reduced the arsenic uptake by rice.•Application of Fe materials effectively reduced arsenic in rice grain.•Application of Fe materials is a promising agronomic practice for reducing arsenic.