A review on ionizing radiation-based technologies for the remediation of contaminated groundwaters and soils

Ionizing radiation (IR) is considered both a technically and economically feasible technology to degrade various types of contaminants and has been frequently used in groundwater and soil remediation. Subsurface contaminants including gasoline additives, aromatic hydrocarbons, chlorinated organic compounds, per- and polyfluorylalkyl substances (PFASs), pharmaceuticals and pesticides, etc. can be effectively decomposed by IR process. This review summarizes for the first time the current knowledge and research advances on IR-based remediation of contaminated groundwaters and soils, and provides a critical evaluation on the research areas, experimental approaches and practical applications of these technologies from an engineering perspective. Both laboratory studies and pilot/full scale investigations are involved with special emphasis to the influence of groundwater composition and operational conditions on the treatment efficiency as well as the toxicity control. Different combinations of IR and other technologies are described and discussed in detail. Relevant insights and recommendations on the actual implementation as well as the further development of IR-based groundwater/soil remediation are proposed from the aspects of absorbed dose, pretreatment technology, experimental strategy, environmental effect, and on-site application.