Selected physicochemical properties of several phenanthrene and anthracene biochemical metabolites (1-hydroxy-2-naphthoic acid, 2,3-dihydroxy naphthalene, 2-carboxy benzaldehyde, and 3,4-dihydroxy benzoic acid) were experimentally measured and/or estimated. These properties, including aqueous solubility, octanol-water partition coefficient, and vapor pressure, were then used to estimate the distribution of these metabolites and associated parent compounds in a contaminated soil using the Fugacity Level 1 model. The resulting information was used to illustrate the use of a chemical mass balance approach to enhance site characterization, remedial treatment technology selection, and monitoring strategies at hazardous waste sites.