Natural environments subjected to hydrologically-driven redox fluctuations are regarded as propitious to contaminant degradation since they favor cyclic oxygenation of Fe(II)-minerals that produces oxidizing reactive species, such as the hydroxyl radical, OH • . However, the identity of these reactive species may vary as a function of physicochemical conditions and is still a matter of research. Here, using spin-trapping electron paramagnetic resonance (EPR) with 5,5-dimethyl-1pyrroline N-oxide (DMPO) as spin trap, we show that a non-hydroxyl reactive species is produced in significant amount upon air-oxidation of alluvial soil suspensions (Seine River basin, France). Indeed, among the DMPO-OH • , DMPO-CO2 •-and DMPO-alkyl • adducts observed, the latter one dramatically raised when adding ethanol or, to a lesser extent, tert-butanol, especially with phosphate buffer. This result revealed a dominant non-hydroxyl species we interpret as Fe(IV) since it is known to oxidize alcohols into alkyl • radicals and to be favored by phosphate ligands. With phosphate buffer and ethanol, the DMPO-alkyl • production correlated with the initial reduced-state iron pool in the samples determined using Fe K-edge X-ray absorption spectroscopy (XAS). Fe(II)-phyllosilicates, and Fe(0) in one soil, and to a lesser extent vivianite, were the most significantly oxidized upon soil oxygenation, pyrite appearing less reactive. Hence, we show that a significant reactive species, differing from OH • , forms upon oxygenation of soil Fe(II)-minerals, especially in the presence of soil-sourced phosphate. Our results may thus call for further direct identification of this putative Fe(IV) species and for investigating its ability to degrade organic contaminants in natural environments.