Analysis of benzene transport in a two-dimensional aquifer model

In this study, the fate and transport of aqueous benzene was investigated in a laboratory-scale homogeneous aquifer by conducting a two-dimensional plume test. Benzene solution was introduced as a pulse type along the width of the aquifer model through a recharge zone situated at the upper-left part of the model and followed by a steady state flow. Solution samples were collected at various locations on the front side of the model to capture two-dimensional plumes at discrete time intervals. The benzene plumes showed a moderate retardation relative to chloride plumes observed from the previous study conducted for the same aquifer model. The retardation factor was obtained from the ratio of travel distances of benzene peaks to chloride peaks from the injection point, computed using a line integral method. Mass recovery of aqueous benzene revealed that there was a significant reduction of benzene mass, indicating the occurrence of volatilization and/or irreversible sorption during transport. Thus, retardation along with volatilization and/or irreversible sorption may be important processes affecting the fate and transport of aqueous benzene in the aquifer model.