Deposition of Polycyclic Aromatic Hydrocarbons in Soil and Litter

摘要

1. PAH/C ratios showed consistent patterns of increasing levels from fresh Oi to partially decomposed Oe and fully decomposed Oa litter (where present), with the exception of the Florida site 2. These patterns indicate that PAH have an affinity to litter and soil C pools, and that residence time of PAH is higher than that of organic carbon, resulting in a significant PAH accumulation in deeper, older ecosystem components 3. The Florida site experiences regular ground-burning (every three to five years) to remove a dense, tropical understory vegetation. The strong PAH enrichment in the unburned Oe litter layer and top soils may be attributed to fire-related emissions and deposition of PAH from these burning activities 4. PAH/C ratios showed consistent patterns of increasing levels from fresh Oi to partially decomposed Oe and fully decomposed Oa litter (where present), with the exception of the Florida site 5. These patterns indicate that PAH have an affinity to litter and soil C pools, and that residence time of PAH is higher than that of organic carbon, resulting in a significant PAH accumulation in deeper, older ecosystem components 6. The strong increases in anthrone (1 ketone group) and athraquinone (2 ketone groups) concentrations with increasing depth in litter and soils may be attributed to increasing microbial degradation in decomposed litter and soil.