Radiation treatment in the presence of catalysts such as anatase, P25 and bentonite showed an efficient removal of TCE and PCE compared with gamma-irradiation only. The gamma-ray pretreatment of P25 and bentonite enhanced the decomposition of TCE and PCE, respectively. The change of the catalysts by gamma-ray was characterized by EPR spectra. For anatase and bentonite, the peaks in the spectra ...