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 polynu clear aromatic hydrocarbons (PAH) were studied in both batch and colum n experiments. The column experiments were conducted in two stages. In the first stage, the soil matrix was simulated with quartz, with whic h NOM does not interact; the effect of aqueous-phase NOM on PAH transp ort was studied in such a soil matrix. In the second stage, the soil m atrix 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 solu bility, NOM source, and Darcy velocity on PAH transport were also addr essed. Data from the column experiments were modeled with a one-dimens ional advection-dispersion transport model (CFITIM) to independently e stimate partition coefficients as well as retardation factors and kine tic parameters. Observations based on the results of experiments inclu de the following: (1) the interaction between PAH and NOM is NOM sourc e dependent, and the interaction between PAH and minerals is mineralog y dependent, (2) aqueous-phase NOM facilitates PAH transport, and (3) solid-phase NOM retards PAH transport.