Aqueous, low-temperature oxidation rates for the polychlorinated biphenyl (PCB) congener 2,2`,3-trichlorobiphenyl have been measured in aqueous phosphate-buffered solutions using Dickson-type reaction vessels. Concentrations of the target compounds were determined by gas chromatography and compound identification was verified by gas chromatography - mass spectrometry. The reaction temperatures ranged from 131 {degrees}C to 165{degrees}C and the activation energy for the destruction of 2,2`,3-trichlorobiphenyl was estimated to be 134 kJ/mole. In a low concentration experiment (approximately 500 ng/g starting concentration), 2,2`,3-trichlorobiphenyl concentration reached non-detect in two days at 135{degrees}C. In a much higher concentration experiment (approximately 24,000 mg/g initial loading), nearly 40% of the initial 2,2`,3-trichlorobiphenyl concentration, or about 10,000 ng/g was destroyed at 161{degrees}C in 18 days. The 2,2`, 3-trichlorobiphenyl concentration of 24,000 ng/g measured at 131{degrees}C represents a greater than 100 fold increase in the aqueous solubility compared to the value of 200 ng/g at 20{degrees}C reported by Mackay et al. During the experiments the reacted portion of the 2,2`, 3-trichlorobiphenyl was completely mineralized, as indicated by a stoichiometric production of inorganic carbon and chloride ion, and no intermediates amenable to gas chromatography were observed during the HPO experiments. These preliminary experiments indicate that hydrous pyrolysis/oxidation (HPO) may be a useful alternative method for remediating soil and groundwater contaminated with PCBs.