Rapid assessment and remediation management of petrochemical-contaminated sites via a geophysical-geochemical synergistic approach

• Our research integrates a geophysical-geochemical synergistic approach for rapid pollution mapping at petrochemical sites. • Nano TEM reveals the spatial distribution and migration path of oil pollution to facilitate precise remediation. • Soil gas measurements show high concentrations of pollutants in the central region. • The results show that the site is suitable for in-situ natural green and low-carbon restoration strategies. • This research provides technical support for pollution remediation management and risk mitigation of petrochemical sites. Assessing soil contamination is essential for evaluating the risk and remediating contaminated sites. The Nano Transient Electromagnetic Method (Nano TEM) is an innovative technique for site pollution detection, known for its simplicity and practicality in pinpointing subsurface anomalies with precision. However, there is a paucity of empirical data regarding its application in site pollution analysis. This research employs a rapid assessment and remediation management of a domestic petrochemical site using a geophysical-geochemical synergistic approach, integrating the nano transient electromagnetic method (Nano TEM) with soil gas measurements. The findings indicated that Nano TEM delineates the spatial distribution, migration pathways, and focal points of oil and gas contamination within the affected area, with high resistivity anomalies predominantly occurring within impermeable barriers. The soil gas measurements revealed that the central region of the survey area exhibits significant concentrations and extents of various pollutants. Soil gas monitoring wells demonstrated low levels of volatile organic compounds (VOCs), with methane and total petroleum hydrocarbons (TPH) showing consistent concentration trends, and elevated CO 2 levels in the southeastern portion relative to the northwestern sector. The predominant reduction in pollutant levels at this site is attributed to natural biodegradation processes, suggesting its suitability for in-situ natural green low-carbon remediation approaches such as Monitored Natural Attenuation (MNA), Monitored Natural Remediation (MNR), and Bio-venting (BV) for site management. This paper delineates pollutant spatial characteristics at the petrochemical site, affirms the feasibility of in-situ natural green low-carbon remediation strategies, and offers foundational data and technical insights for management and risk mitigation.