(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.