Abstract: Methylmercury (MeHg) has a strong neurotoxicity, and the health risk caused by its accumulation in rice grain has gained a lot of attention. The origin of MeHg in rice (Oryza sativa L.) comes mainly from paddy soil. The spatial variation of iron and sulfur contents in soil is large, and the interaction of iron and sulfur  changes with the course of wet and dry alternation in rice planting and O₂ secretion from rice roots. Changes of the content and transformation of MeHg in soil influence the MeHg availability to rice plants. This review comprehensively summarized the research achievements of iron and sulfur and their interaction effects on mercury methylation and MeHg migration and transformation in soilrice system, and put forward the potential aspects of future studies. This review will benefit further research on the regulation of MeHg formation and uptake, and on the reduction of health risks of MeHg.

Key words: dry matter production, ditch-buried organic matter, irrigation amount, maize, photosynthetic characteristics