海岸带环境过程实验室知识库

(1) 中国科学院海岸带环境过程与生态修复重点实验室/中国科学院烟台海岸带研究所

Soil is a complicated system with multiple media, multiple interfaces and the interactions of living organisms and non-living matters.Such system determines the interfacial reaction, distribution, transmission, accumulation, transformation and degradation of toxic pollutants.In the field of environmental science and soil remediation, it is an international frontier topic to study the coupling mechanism of multi-interface processes of toxic pollutants.Diphenylarsinic acid (DPAA)is a stable class of oxidized or hydrolyzed product of diphenylcyanoarsine and diphenylchloroarsine, which are the main components of arsenic-containing chemical weapons.DPAA is also one of the most important organoarsenic compounds detected in the soil of chemical weapons burial areas.Here, we reviewed the dynamic characteristics and influencing factors of DPAA adsorption-desorption on various types of soil particles, the binding species and molecular bonding mechanism of DPAA on the surface of soil particles and ferric oxides, and further the aerobic biodegradation and anaerobic metabolic transformation mechanism of DPAA.The adsorption isotherm of DPAA in soil conforms to the Freundlich equation and Henry equation.The key environmental factors for the adsorption and release of DPAA included soil pH,phosphate, salinity, oxide, organic matter and microorganisms.DPAA was adsorbed to the surface of soil mineral colloids mainly via electrostatic attraction, and could further form bidentate binuclear inner-and outer-sphere bonds on the surfaces of soil particles and ferric oxides.In aerobic soil environments, the degradation metabolites of DPAA included mono-hydroxylated DPAA, phenylarsinic acid, and inorganic arsenate.While in anaerobic environments, DPAA could not only form phenylarsinic acid, and arsenate via benzene removal, but also be anaerobically converted into diphenylthioarsinic acid and methylated diphenylarsone by sulfate-reducing bacteria.Future studies could focus on the speciation and bioavailability of DPAA in various types of soil-groundwater environments mediated by microorganisms.Furthermore, multi-omics correlation analysis technology could be jointly applied to disentangle the molecular coupling mechanisms among DPAA anaerobic metabolism, sulfate reduction, and iron reduction processes mediated by sulfatereducing bacteria.Such mechanisms and knowledges could provide theoretical and technical supports for the bioremediation of organoarsenic-contaminated soils in China's chemical weapon buried areas.

土壤是一个多介质、多界面、生命与非生命体系交叉的复杂系统,决定着土壤中毒害污染物的界面反应、分配、传递、积累、转化和降解等过程。研究毒害污染物在土壤中多界面过程的耦合机制是国际环境科学与土壤修复研究领域的前沿课题。二苯砷酸(Diphenylarsinic acid,DPAA)是含砷化学武器的主要成分二苯氰砷和二苯氯砷在环境中氧化或水解后形成的一类稳定的有机砷化合物,也是化学武器掩埋区土壤中最主要的有机砷污染物之一。文章综述了DPAA在不同类型土壤颗粒表面的吸附解吸动态特征及其影响因素、DPAA在土壤颗粒及铁氧化物表面的结合形态与分子键合机制,以及土壤中DPAA的好氧微生物降解与厌氧微生物代谢转化机制。DPAA在土壤中的吸附等温线符合Freundlich方程和Henry方程,土壤pH、磷酸盐、盐度、氧化物和有机质等环境因子以及微生物在土壤中DPAA的吸附与释放等过程中发挥着关键作用。DPAA主要通过静电引力吸附到土壤矿质胶体表面,并可在土壤及铁氧化物表面生成内圈层双齿双核络合物和外圈层络合物。土壤中的好氧微生物对DPAA的好氧降解代谢产物包括单羟基化DPAA、苯砷酸和无机砷酸盐;而在厌氧环境下,DPAA不仅可脱苯环形成苯砷酸和砷酸盐,还可被土壤中的硫酸盐还原菌厌氧转化为二苯基硫代砷酸以及甲基化二苯砷酸。未来应加强有关微生物参与下DPAA在不同类型土壤-地下水环境中的赋存形态与生物有效性研究,并结合多组学关联分析技术,阐明硫酸盐还原菌介导的DPAA厌氧代谢转化过程与硫酸盐还原、铁还原等过程之间的分子耦合机理,为中国日遗化学武器埋藏区有机砷污染土壤的生物修复提供理论依据与技术支持。