Predicting aqueous concentrations of polynuclear aromatic hydrocarbons in complex mixtures

The release of polynuclear aromatic hydrocarbons (PAHs) from buried organic wastes into groundwater occurs over long periods of time. Estimation of the equilibrium aqueous concentration or "solubility" of PAHs in mixtures of contaminated soil and water can aid in predicting fate and transport processes. Four methods were evaluated for their effectiveness in predicting aqueous concentrations of 16 PAH compounds. The results indicated that a cosolvent method was extremely effective in predicting aqueous concentrations and that equilibrium models (Raoult's law) provided estimates within an order of magnitude of PAH concentrations in complex mixtures. Predicted concentrations from soil-water partition coefficients$(K_{{\rm p}})$generally were within an order of magnitude of actual concentrations.