MODELING PARTITIONING AND TRANSPORT INTERACTIONS BETWEEN NATURAL ORGANIC-MATTER AND POLYNUCLEAR AROMATIC-HYDROCARBONS IN GROUNDWATER

The influences of aqueous-phase natural organic matter (NOM) and solid-phase (mineral-phase) NOM on the partitioning and transport of polynuclear aromatic hydrocarbons (PAH) were studied in both batch and column experiments. The column experiments were conducted in two stages. In the first stage, the soil matrix was simulated with quartz, with which NOM does not interact; the effect of aqueous-phase NOM on PAH transport was studied in such a soil matrix. In the second stage, the soil matrix was simulated with quartz coated with aluminum oxide (mixed bed), with which NOM can interact (sorb); the effect of soil-phase NOM on PAH transport was studied in this stage. The effects of PAH water solubility, NOM source, and Darcy velocity on PAH transport were also addressed. Data from the column experiments were modeled with a one-dimensional advection-dispersion transport model (CFITIM) to independently estimate partition coefficients as well as retardation factors and kinetic parameters. Observations based on the results of experiments include the following: (1) the interaction between PAH and NOM is NOM source dependent, and the interaction between PAH and minerals is mineralogy dependent, (2) aqueous-phase NOM facilitates PAH transport, and (3) solid-phase NOM retards PAH transport.