Simulated oil release from oil-contaminated marine sediment in the Bohai Sea, China.

There is a high degree of heavy oil partitioning into marine sediments when an oil spill occurs. Contaminated sediment, as an endogenous pollution source, can re-pollute overlying water slowly. In this study, a static oil release process and its effects in marine sediment was investigated through a series of experiments with reproductive heavy oil-contaminated marine sediment. The oil release process was accurately simulated with a Lagergren first-order equation and reached equilibration after 48h. The fitted curve for equilibrium concentration (C) and first-order rate constant (k) for sediment pollution levels exhibited a first-order log relationship. The instantaneous release rate (dCdt) was also calculated. The C increased with increases in temperature and dissolved organic matter (DOM), and decreasing salinity. The k increased with temperature, but was not affected by DOM and salinity. These results can be used to better understand the fate of heavy oil in contaminated sediments of the Bohai Sea.