ABSTRACT
Nonoxygenated aromatic and alicyclic compounds comprise several significant categories among environmental pollutants frequently encountered in aquatic and terrestrial environments. Aromatic and alicyclic compounds, including pollutants, can eventually reach anaerobic regions but will not remain intact. A comparison of anaerobic transformation of such compounds between soil, subsurface, and sediments in situ and small laboratory systems simulating the ecosystems indicates that many parallels exist between the two. Heterocyclic compounds are more susceptible to anaerobic oxidation than homocyclic aromatics, because of the instability that the heteroatom imparts to the ring structure. The initiation of the transformation of halogenated aromatic hydrocarbons under anaerobic conditions occurs through reductive de-halogenation. Theoretically, highly halogenated ring compounds might serve as exogenous electron acceptors for microroganisms under anaerobic conditions. Anaerobic and facultatively anaerobic microorganisms in soil, subsurface, and sediments represent a significant factor that influences the fate of nonoxygenated aromatic and alicyclic pollutants in the environments.
