[Multimedia fate modeling with spatial resolution for phenanthrene in Tianjin].

Behavior and fate of phenanthrene in various phases in Tianjin were calculated using a multimedia model with spatial resolution under steady-state assumption. Spatial variation of two parameters, namely soil organic carbon content and emission from fossil fuel combustion, were taken into consideration. Both soil and air phases were further divided into 3113 sub-compartments and 6226 equations in total were solved simultaneously under mass-balance assumption. A number of output parameters, therefore, were generated and were used for mapping of phenanthrene concentrations in soil and air, as well as transfer fluxes between compartments. The model was evaluated in two ways. 1. Comparison between the calculated and the observed average concentrations in bulk compartments, and 2. Comparison of spatial distribution of the calculated and the observed phenanthrene concentrations in surface soil. In both cases, the predicted results are in fair agreement with the independently measured values. As the results of the modeling, it was demonstrated that soil and sediment, especially the later, is the primary sink of phenanthrene in the area over 70% of the chemical accumulated in sediment. The spatial distribution pattern of phenanthrene in surface soil depends on content of soil organic matter which prevent the degradation of the material by bacteria. For distribution in ambient air, the dominant controlling factor is the emission.