Effects of heterocyclic PAHs (N, S, O) on the biodegradation of typical tar oil PAHs in a soil/compost mixture.

The interaction phenomena during the biodegradation of typical coal tar polycyclic aromatic hydrocarbons and their heterocyclic analogues (N, S, O) were investigated in an artificially contaminated AhA1-horizon/compost mixture. All compounds were partly or completely biodegraded. Degradation of two- to five-ring PAHs was inhibited by the presence of hetero-PAHs, whereas degradation of just some hetero-PAHs was inhibited by the presence of PAHs. Among the hetero-PAHs the sulphur-containing compounds were less susceptible to degradation than the corresponding oxygen- or nitrogen-containing analogues. The basic azaarene acridine showed an extreme persistence and strong sorption to the soil matrix proved by an increase of recovery after saponification of the soil matrix.