US EPA

2136094 

Journal Article 

Hysteresis in the sorption and desorption of hydrophobic organic contaminants by soils and sediment: 2. Effects of soil organic matter heterogeneity 

Weber W J, , JR; Huang, W; Yu, H 

1998 

1 

Journal of Contaminant Hydrology
ISSN: 0169-7722
EISSN: 1873-6009 

BIOSIS/98/20299 

31 

1-2 

1-2 

eng 

BIOSIS COPYRIGHT: BIOL ABS. 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