In this paper a generalization of the TAU-transform method introduced by Turai (1985) is presented. On combining the TAU transform method and the tools of inverse problem theory a general algorithm for the determination of the time-constant spectrum of the polarizability data (deduced from time-domain IP measurements) is available for the general case of continuous spectra (Turai, Dobróka, 2001). In the practice we use global inversion method for determination the time-constant spectra. <br>Induced Polarization is a very useful geophysical method also in the detection and haracterization of environmental spots mainly waste sites.