Fate simulation of PAHs in Lanzhou City by multimedia model
兰州城区多环芳烃的多介质归趋模拟研究

The Multi-media Urban Model (MUM) was used to simulate the concentration distribution of 16 species of PAHs in the air, water, soil, sediment, suspended solid, fish, vegetation, and organic film of Lanzhou City under a steady-state assumption. Comparing with the measuring value and according to simulation results, the transferring or exchanging fluxes between the phases were calculated. By using MUM, it was shown that the organic film achieved the highest concentrations in contrast to air, water, soil, sediment, suspended solid, fish, and vegetation, while the concentration of PAHs in the air were the lowest. It was demonstrated that the major source of PAHs in the area was combustion of fossil fuel. The transport process included diffusion, sedimentation, erosion, etc.; while degradation in soil was the main loss in the system. The largest sink for PAHs in Lanzhou City is soil, accounting for about 99.86% of the total amount remaining in the system. With the increasing rings, the advective outflow flux in the air decreased gradually, and the reaction loss proportion of PAHs in the air also decreased. The organic film on impervious surface enhanced the exchange and mobility of PAHs at the interface between air and water. The reliability of the model was verified by the coincidence between the calculated and measured the concentrations. The key parameters of the model were identified by sensitivity analysis.