Modeling the transport of dissolved contaminants originating from a nonaqueous phase liquid source containing polycyclic aromatic hydrocarbon compounds in groundwater

A three-dimensional mathematical model is developed for simulating the transport of dissolved contaminants originating from a well-defined, multicomponent nonaqueous phase liquid (NAPL) source containing polycyclic aromatic hydrocarbon (PAH) compounds in groundwater. The dissolution process for each NAPL component is envisioned to occur in a successive series of small dissolution intervals (or pulses). The equilibrium aqueous phase concentration of each component and the source dimensions are assumed to remain constant for the duration of each dissolution interval. The model accounts for possible solidification of PAH components as the NAPL source dissolves. Aqueous phase contaminant concentrations resulting from each dissolution interval are calculated using an existing analytical solution. A synthetic PAH-rich NAPL mixture consisting of benzene and eight PAH components is used for model simulations. The model is useful for evaluation and prediction of downstream aqueous phase contaminant concentrations resulting from dissolution of a PAH-rich NAPL source. Key words: contaminant transport, groundwater, nonaqueous phase liquid (NAPL), mathematical modeling, polycyclic aromatic hydrocarbons.