摘要
全世界约一半人口以大米为主食,亚洲人口主食对水稻的依赖程度甚至超过90%。当前全球各地均存在不同程度的砷(As)污染,水稻容易在籽粒中积累砷,从而使砷通过食物链进入人体,威胁人体健康。水稻中砷含量水平为几个到几百个ng/g不等,砷从土壤进入水稻的过程涉及复杂的物理化学过程和形态转化,最终主要以砷酸、亚砷酸及砷的巯基、甲基配位等形态储存于大米中。田间水管理、施肥以及添加土壤改良剂等方法都可以控制稻田农田生态系统中水稻对砷的吸收,但是每种技术都有其优势和局限性。水稻农田生态系统中砷生物地球化学及水稻对砷的吸收和代谢等诸多因素都影响着水稻及谷粒中砷的浓度。综合考虑农艺活动对土壤中pH、氧化还原条件、有机质结构和共存元素等因素的影响,考虑不同的地域特征和经济因素,是在生产实践中实现控制水稻对砷吸收的关键。综合运用多种农艺方法进行水稻耕作是未来控制水稻吸收砷的重要途径;新型农艺方法在控制水稻吸收砷过程中的应用,气候变化对大米吸收砷的影响,以及非破坏原位与活体分析技术在砷形态分析中的应用,是未来在全球尺度上更科学有效地控制大米中的砷含量、降低人体砷暴露风险的关键,也是未来的重点发展方向和艰巨挑战。
BACKGROUND:Rice 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.OBJECTIVES:To reveal the mechanism of As absorption in rice.METHODS:The 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.RESULTS:The 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.CONCLUSIONS:Comprehensive 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.
作者
杨文蕾
沈亚婷
YANG Wen-lei;SHEN Ya-ting(National Research Centrefor Geoanalysis,Beijing 100037,China;China University of Geosciences(Beijing),Beijing 100083,China;Key Laboratory of Eco-Environmental Geochemistry,Ministry of Natural Resources,Beijing 100037,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2020年第4期475-492,共18页
Rock and Mineral Analysis
基金
国家自然科学基金面上项目(41877505)
国家重点研发计划项目(2016YFC0600603)。
关键词
水稻
砷
铁膜
灌溉
水管理
施肥
土壤改良剂
健康地质
rice
arsenic
iron plaque
aerobic irrigation
water management
fertilization
soil amendment
healthy geology