Using the fluorescence, IR, and electronic spectroscopy methods, we have investigated the spectral characteristics of the surface of a polypropylene microfiber before and after their UV irradiation. We have studied the degradation of naphthalene and phenol in water exposed to UV radiation in the presence of fibers. As a radiation source, we used a KrCl excilamp with a radiation wavelength of 222 nm. It has been revealed that, after irradiation, photooxidation of the fiber surface occurs. The degree of crystallinity of examined samples remains almost the same after their irradiation. We show that, as a result of the adsorption of naphthalene and phenol on the fiber surface, their concentration in aqueous solutions efficiently decreases. Maximally, the concentration of naphthalene decreased 21-fold and that of phenol decreased 4-fold. Under UV irradiation of the system toxicant + water + fiber by the KrCl excilamp, fluorescent photoproducts are formed in the system and are adsorbed on the fiber surface.