Investigation of Pyrene Degradation and Bound Residue Formation on Environmental Surfaces

INTRODUCTION Polycyclic aromatic hydrocarbons (PAH) are one of the primary contaminants of concern at the Champion International Superfund Site in Libby, Montana. Contaminated soil at the Libby site is currently being treated by bioremediation that results in contaminant loss mechanisms including mineralization and formation of bound residues (Nieman et al., 1999). Our current work involves the use of synchrotron based FTIR spectromicroscopy at the Lawrence Berkeley National Laboratory (LBNL) Advanced Light Source (ALS) beamline 1.4.3 to observe pyrene degradation in model environmental systems. This instrument was recently used to monitor bacterial chromium reduction on a basalt surface (Holman et al., 1999). Our research team used synchrotron based FTIR spectromicroscopy to characterize the degradation of pyrene on a magnetite surface by three bacterial strains isolated from contaminated soil from the Champion International Superfund site in Libby, Montana. The three strains were characterized as Mycobacterium Spp. by grams stain, 16S ribosomal RNA, and fatty acid analyses. They were isolated from soil samples from the Libby site, are capable of C-pyrene degradation, and were shown to metabolize C-pyrene to CO2 in the absence of other carbon sources (unpublished data from UWRL).