A review of the effects of typical biogeochemical and hydrogeological features on the natural attenuation of soil petroleum contaminants

Oil spills in soil can form source areas of contamination that are ecologically hazardous in the long term. The natural process by which the concentration, toxicity and mobility of petroleum contaminants in soil decrease under the combined effects of biochemistry and other aspects without human interference is called natural attenuation. This paper provides a systematic review of the natural attenuation characteristics of petroleum contaminants in soil and its research tools, focusing on the typical biogeochemical and hydrogeological characteristics of the site, and describes the influence of both on the natural attenuation process of contaminants in soil and its mechanism. It also clarifies the influence of petroleum properties, sediment types, organic matter changes, photo-oxidation reactions and microorganisms on the natural attenuation of the source area, and summarises the relevant indicators that can characterise the natural attenuation of petroleum contamination in the source area; at the same time, it outlines the various types of prediction methods of natural attenuation processes, and points out the focus and difficulties of the multidisciplinary fusion of the research directions and the multi-data drive, and finally puts forward a proposal for the study of natural attenuation of petroleum in soils. Finally, the research on the natural attenuation of soil oil pollution source area is proposed. Overall, due to the complexity of organic matter, mineral and microbial components, and the inhomogeneity of hydrogeological conditions, the study of the influence of the intrinsic properties of the site on the natural attenuation of pollutants needs to be further strengthened, and this paper focuses on the identification of the spatial and temporal dynamics of the natural attenuation of pollutants, and the deepening of the understanding of the interaction mechanisms between typical biogeochemical and hydrogeological conditions of the site and the pollutants.