Sorption and desorption equilibria were measured for phenanthrene and 12 different soil and sediment samples using an experimental protocol described in the companion paper of this two-part series. Ten of the 12 sorbents studied were found to exhibit statistically significant sorption-desorption hysteresis, with those containing diagenetically-altered soil organic matter (kerogens) doing so to greater extents than those containing geologically- younger humic soil organic matter. Correlations between the extent of hysteresis and the characteristics of 13C-NMR spectra indicate that particle-scale soil organic matter heterogeneity significantly affects this phenomenon. The experimental observations are mechanistically consistent with a conceptual model based on polymer sorption theory, the Dual Reactive Domain Model (DRDM). The work reinforces the general suitability of the DRDM for characterizing sorption-desorption interactions between hydrophobic organic contaminants and soils and sediments.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Water Science and Technology
- Desorption hysteresis
- Soil heterogeneity