 Metallic iron (Fe0) is a reactive material that is widely used for industrial water treatment. The course of the metal ion removal process using Fe0 (iron powder) was monitored electrochemically (differential pulse polarography). As probe species, Zn2+, Pb2+, and Cd2+ were selected for their different (1) adsorptive affinity to iron corrosion products (FeCPs), (2) redox properties, (3) precipitation ability at various pH. Batch experiments were carried out with binary (Zn2+/ Pb2+ and Zn2+/ Cd2+) and ternary (Zn2+/Cd2+/Pb2+) systems to reveal the mutual interference of these cations. Detailed time monitoring of iron aging for up to 14 days as well as concentration decay of individual removed cations represent important data for mechanistic discussions. The aqueous concentration of Fe2+ was also monitored. FeCPs were characterized using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Results showed that the presence of Pb2+ delays the Zn2+ removal whereas the presence of Cd2+ in solution accelerates its removal. The removal of Pb2+ by FeCPs was not affected by the presence of Zn2+ and Cd2+, moreover, the Pb2+ inhibited the effect of Cd2+ on the removal of Zn2+. XPS has proven existence of Fe2O3 and hydrated Fe oxidic phase, whilst the SEM showed that the original Fe grains were partly dissolved into buffered ambient under formation of fine particles of FeCPs. Results confirm that reductive transformation of any contaminant in a Fe0/H2O system is the consequence and not the cause of iron corrosion.