TRANSPORT OF DISSOLVED ORGANIC MACROMOLECULES AND THEIR EFFECT ON THE TRANSPORT OF PHENANTHRENE IN POROUS-MEDIA

The retardation factor (R) of phenanthrene in a sand column was reduced by an average factor of 1.8 in the presence of dissolved organic matter (DOM) derived from soil, suggesting that a phenanthrene-DOM "complex" enhanced the transport of phenanthrene. Distribution coefficients (K(d),s) were determined in batch and column studies for combinations of phenanthrene and DOM with sand. The retardation factor in the advective-dispersive transport equation was modified to reflect the presence of a carrier by incorporating both the retardation and pore exclusion of the carrier itself. The best prediction of phenanthrene transport in the presence of DOM was provided by modeling the retardation by using two K(d),s) derived from column experiments of DOM alone and phenanthrene alone, along with the K(d) for phenanthrene binding to DOM. Sensitivity analyses indicated that the critical model parameters are the distribution coefficients for the hydrophobic pollutant binding to the stationary phase and binding to the carrier, as well as the carrier concentration.