The bioavailability and toxicity of mercury (Hg) are dependent on its chemical speciation, in which methylmercury (MeHg) is the most toxic compound. Inorganic Hg can be transformed into MeHg in anaerobic conditions. Subsequent accumulation and biomagnification in the food chain pose a potential threat to human health. Previous studies have confirmed that paddy soil is an important site for MeHg production, and rice fields are an important source of MeHg in terrestrial ecosystems. Rice (Oryza sativa L.) is recently confirmed as a potential bioaccumulator plant of MeHg. Understanding the behaviour of Hg in rice paddies is important, particularly the mechanisms involved in Hg sources, uptake, toxicity, detoxification, and accumulation in crops. This review highlights the issue of MeHg-contaminated rice, and presents the current understanding of the Hg cycling in the rice paddy ecosystem, including the mechanism and processes of Hg species accumulation in rice plants and Hg methylation/demethylation processes in rice paddies and the primary controlling factors. The review also identified various research gaps in previous studies and proposes future research objectives to reduce the impact of Hg-contamination in rice crops.

汞（Hg）的生物利用度和毒性取决于其化学形态，其中甲基汞（MeHg）是最具毒性的化合物。无机汞可以在厌氧条件下转化为甲基汞。食物链中随后的积累和生物放大作用对人类健康构成潜在威胁。先前的研究证实，稻田土壤是生产甲基汞的重要场所，稻田是陆地生态系统中甲基汞的重要来源。水稻（水稻L.）最近被确认为潜在的MeHg生物蓄积植物。了解稻田中汞的行为很重要，尤其是涉及汞源，吸收，毒性，排毒和农作物积累的机制。这篇综述突出了被甲基汞污染的水稻的问题，并提出了对稻田生态系统中汞循环的当前理解，包括水稻中汞物种积累的机理和过程以及稻田和主要稻田中汞的甲基化/去甲基化过程。控制因素。审查还确定了以往研究中的各种研究差距，并提出了未来的研究目标，以减少汞污染对水稻作物的影响。