摘要
Modeling the fate and transport of organic pollutants at contaminated sites is critical for risk assessment and management practices,such as establishing realistic cleanup standards or remediation endpoints.Against the conventional wisdom that highly hydrophobic persistent organic pollutants(POPs)(e.g.,polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons)in surface soils are essentially immobile,mounting evidence has demonstrated the potential of these contaminants leaching into the groundwater,due to enhanced transport by soil colloids.Here,we develop a Colloids-Enhanced Transport(CET)model,which can be used as a simple screening tool to predict the leaching potential of POPs into groundwater,as mediated by soil colloids.The CET model incorporates several processes,including the release of POPs-bearing colloids into the porewater,the vertical transport of colloids and associated POPs in the vadose zone,themixing of POPs-containing soil leachate with groundwater,and the migration of POPs-bearing colloids in saturated zone.Thus,using parameters that can be easily obtained(e.g.,annual rainfall,soil type,and common hydrogeological properties of the subsurface porous media),the CET model can estimate the concentrations of POPs in the saturated zone from the observed POPs concentrations in surface or shallow subsurface zones.The CET model can also be used to derive soil quality standards or cleanup endpoints by back-calculating soil concentrations based on groundwater protection limits.
基金
supported by the National Key Research and Development Program of China(No.2019YFC1804202)
the National Natural Science Foundation of China(Nos.22020102004 and 22125603)
Tianjin Municipal Science and Technology Bureau(No.21JCZDJC00280)
the Fundamental Research Funds for the Central Universities,and the Ministry of Education of China(No.T2017002).
