| Abstract
| - This study was carried out to assess the influence ofPAH sequestration in sterile sewage sludge-amended arablesoil on their dissolution behavior. Radiolabeled phenanthrene(14C-9-Phe), pyrene (14C-4,5,9,10-Pyr), and benzo[a]pyrene (14C-7-B[a]P) were spiked and aged for up to 525days in sterile soil microcosms. The dissolution behavior ofthe compounds was determined at various times usingan in-situ XAD-2 sorbent method. The XAD procedure allowedthe detection of hydrophobic PAHs released from thesoil and demonstrated that a fraction of PAH was resistantto dissolution. The experimental data generated wasanalyzed using an empirical two-site model, and fittedvalues were obtained for the magnitude of the rapidlyreleased compound fraction and the rate of release for therapid and slowly released compound fractions. Increasingsequestration did not reduce the size of the rapidlyreleased compound fraction in this soil. We did, however,observe a decrease in the rate of the fast releasedfraction of 14C-7-B[a]P which formed a significantly largersequestered fraction. The duration of the dissolutionexperiments proved insufficient to obtain precise estimationsfor the rate of slow compound release from the soil, andwe were unable to determine whether sequestration affectedthe rate of release for the slowly released compoundfraction. These results demonstrate the necessity ofconducting desorption experiments for a period of monthsif complete data on the long-term release of desorptionresistant compound fractions is to be obtained.
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