Simulation and Analysis of Oil Pollutant Diffusion in River Affected by Coking Wash Oil Contaminated Groundwater

<p indent="0mm"> In recent years, there has been a frequent occurrence of sudden oil-related water pollution incidents. Accurately identifying the migration patterns of oil pollutants in water has become crucial for emergency response. This study uses the 3EWATER water quality model to investigate the migration patterns of leaked wash oil from a coking company in a karst landscape after it enters the groundwater and surfaces in valley river channels. The results indicate that the karst system accumulates oil pollutants and rainfall significantly increases pollutant concentrations in the water. When the Manning coefficient for the river is set to 0.13, the correlation coefficient between the simulated flow velocity and the measured flow velocity at the hydrological station is 0.92, indicating high simulation accuracy. At the point of interest 3.4 km from the exposure point, the simulated concentration range is <sc>0.05-15.3 mg/L,</sc> while the measured concentration range is 0.05-35.10 mg/L, with a correlation coefficient of 0.77. At the point of interest 18 km from the exposure point, the simulated concentration range is <sc>0.05-0.83 mg/L,</sc> while the measured concentration range is <sc>0.05-9.32 mg/L,</sc> with the correlation coefficient decreases to 0.33. This reflects that oil pollutants from wash oil exhibit unique physical and chemical transformation mechanisms and movement patterns in the water bodies of natural karst rivers due to their complex chemical composition. The findings of this study expand the application of numerical simulation in complex water bodies and the unique oil pollution scenarios, providing a reference for understanding the migration of oil pollution peaks and scientifically implementing response measures.