Selective and regenerable ion-exchange technology has been developed for removing perchlorate (ClO4-) from contaminated water at trace concentrations. The technology relies on a unique, bifunctional anion-exchange resin to sorb ClO4- selectively, and the resin is then regenerated using tetrachloroferrate displacement techniques. The regeneration technology enables quantitative recovery of perchlorate from contaminated water or other environmental matrices such as plants, sediments and/or salt deposits for possible reuse or for isotopic source identification. Naturally-forming perchlorate has been found to contain distinct oxygen and chlorine isotope signatures as compared with anthropogenic perchlorate, thereby allowing unambiguous identification of sources of perchlorate for environmental forensics.