This study shows that iodinated organic compounds can be produced when iodide-containing waters are in contact with manganese oxide bimessite (delta-MnO2) in the pH range of 5-7. In the absence of natural organic matter (NOM), iodide is oxidized to iodate that is also adsorbed onto delta-MnO2, In the presence of iodide and NOM, adsordable organic iodine compounds (AOI) are formed at pH