BACKGROUNDRice is the staple food of about half of the world's population, and the dependence of Asian staple food on rice exceeds 90%. There are varying degrees of arsenic (As) pollution all over the world. As can accumulate in rice and enter the human body, causing health problems.

OBJECTIVESTo reveal the mechanism of As absorption in rice.

METHODSThe content and species characteristics of As absorbed by rice and the species analysis techniques were reviewed. The mechanisms of As absorption, tolerance and detoxification by rice were summarized.

RESULTSThe content of As in rice ranged from a few to several hundred ng/g. The process of As entering the rice from the soil involved complex physical and chemical changes and species transformation. Arsenic mainly existed in the form of arsenate, arsenite, thiol and methyl coordination in rice. Field water management, fertilization and soil amendments controlled the absorption of As in rice. Each technique had their advantages and disadvantages. Soil pH, redox conditions, organic matter and coexisting elements were the key factors affecting As absorption by rice. Agronomic methods can control the absorption of As by rice. Many factors such as arsenic biogeochemistry and the absorption and metabolism of arsenic in rice agroecosystems affect the concentration of arsenic in rice and grain. Comprehensive consideration of the effects of agronomic activities on soil pH, redox conditions, organic matter structure and coexisting elements, and different geographic factors such as soil characteristics and economic factors were the keys to realize the control of arsenic absorption by rice in production practice.

CONCLUSIONSComprehensive use of multiple agronomic methods for rice farming is an important way to control the absorption of arsenic in rice in the future. Application of new agronomic methods in the control of arsenic absorption by rice, the impact of climate change on arsenic absorption by rice, and application of non-destructive in situ and in vivo analysis techniques for As speciation analysis, are keys for more scientifically and effectively controlling the arsenic content in rice and reducing the risk of human As exposure on the global scale in the future. These are also the key development directions and challenges in the future.