土壤中砷的形态分析和生物有效性研究进展

土壤砷污染是当今全球十分严重的环境与健康问题之一。土壤砷形态及生物有效性研究是开展污染诊断、评估环境健康风险及开展砷污染土壤修复的重要依据。目前土壤砷形态的研究方法包括化学选择性提取操作定义法、溶剂提取仪器测定或吸附材料选择性分离法和同步辐射X射线近边能谱（XANES）直接测定法，这些方法相互结合在土壤砷的形态转化研究中发挥着重要作用。目前关于生物有效性研究存在多种方法并存的局面，化学提取法相对经济、方便，但存在很大的局限性，往往不能真实反映土壤砷的有效态含量，只能作为环境危害程度识别的参考；植物指示法需选择敏感性植物方能有效地指示土壤砷对环境与健康的潜在危害；土壤动物与微生物指示法代表了未来开展砷污染早期预警的发展方向，具有广阔的应用前景。模拟肠胃液提取法(In Vitro Gastrointestinal Method)比较接近动物或人体对土壤砷污染的真实吸收状态，在环境健康风险评价中发挥着重要作用。目前国外已发展出采用兔、仔猪和猴的动物模型以研究经口摄入的生物有效性砷，但尚不清楚哪种动物模型更能准确反映砷对人体的生物有效性。

Progress in the Study of Arsenic Species and Bioavailability in Soils -A Review

Arsenic contamination in soil has become a concern worldwide.The studies of arsenic forms/species and bioavailability are the foundation for pollution recognition,risk assessment and remediation criteria setting.Methods currently employed for arsenic fractionation and speciation include chemical selective extraction,instrumental detection or resin/cartridges separation after solvent extraction and synchrotron radiation XANES direct detection.The combination of the above various methods have played a core role in the study of arsenic bioavailability.Also,various methods have been used for measurement of arsenic bioavailability in soils.Chemical extraction is cost effective and the most convenient,but limited in not really reflecting the arsenic bioavailability from soils to animals or humans,and usually is used as reference for recognition of arsenic environmental hazards;Indicator plant method rely on successful selection of sensitive plants in order to give clue to the potential hazards of arsenic to environment and health;The population and structure as well as genetic changes of microorganisms exposed to arsenic in soils are direct in interpretation of arsenic toxicity,and are in priority in future application for risk assessment of arsenic contamination.In vitro gastrointestinal method is the most efficient in simulating the state and condition of animal and/or human gastrointestinal system,and is vital in application for risk assessment of arsenic contamination.However,correlation between in vitro and in vivo results is still needed for its accurate interpretation for arsenic risks.Rabbit,young swine and monkey have been commonly used in animal model(in vivo) for measurement of arsenic availability in soils via detection arsenic contents in their urines.However,it is not yet clear which is the most suitable for the reflection of arsenic risks to humans due to limited studies on such kind of studies with relation to human arsenic exposures.