Interaction of spilled fuel oil with coastal sand

Fuel oil spills represent a significant threat to estuarine and coastal ecosystems, where interactions between petroleum hydrocarbons, sand, and seawater determine both the persistence of contamination and the potential for remediation. In this study, we investigated the infiltration and retention of spilled fuel oil in coastal sands, using the Kerch Strait tanker accident as a model scenario. Laboratory experiments quantified the kinetics of fuel oil migration in dry versus seawater-saturated sands and revealed strong dependence on temperature and viscosity. A temperature–viscosity superposition principle was developed, enabling long-term prediction of fuel oil transport based on accelerated testing. Results demonstrated that wet sand acts as a natural barrier to infiltration, whereas dry sand facilitates progressive penetration. In submerged conditions, fuel oil tends to separate and float to the surface despite temporary stabilization in mixtures with sand. These findings provide new insight into the fate of heavy petroleum residues in coastal environments and inform strategies for shoreline remediation following spill events.