The effects of soil/sediment organic matter on mineralization, desorption, sequestration, and transformation of phenanthrene

The bioavailability and desorption profiles as well as the extent of sequestration and transformation of phenanthrene were assessed using three sorbents that had been previously classified based on the Distributed Reactivity Model (DRM). These phenomena were shown to vary with the degree of diagenesis of the sorbent, supporting the applicability of the DRM to predict contaminant fate. Contaminants sorbed to geologically young sorbents will desorb at a faster rate and thus be more readily bioavailable than contaminants sorbed to geologically older sorbents. However, the final extent of mineralization was comparable for all geosorbents regardless of geological age. Results from methanol Soxhlet extraction of the sorbents imply that biological activity alters the soil organic matter (SOM) and changed the nature of sequestration and transformation. This alteration is more pronounced for geosorbents that are younger, more chemically oxidized, and more biologically active. No significant differences were found for phenanthrene-sorbent contact periods of 2 and 4 months.