Generation of •OH, O2•−, and H2O2 in ultrapure water under 50-Hz ELF–EMF exposure

This study investigates the long-term generation of reactive oxygen species (ROS) in ultrapure water exposed samples (ES) to extremely low-frequency electromagnetic fields (ELF-EMF; 50 Hz, 1 mT) under controlled, external non-thermal conditions. The ROS hydroxyl radicals (•OH), superoxide radicals (O2•−), and hydrogen peroxide (H2O2) were quantified in over 1 year in ES relative to matched non-exposed samples (NES). The net ROS differences (ES minus NES) exhibited accelerating temporal trajectories that were well described empirically by exponential functions. This exponential behavior is interpreted as a descriptive temporal pattern rather than as evidence of a specific kinetic or autocatalytic amplification mechanism. The empirical exponential coefficients decreased in the order •OH > O2•− > H2O2, corresponding to progressively longer characteristic and doubling times for the respective ROS trajectories. These observations are compatible with the possibility that small ELF-EMF-associated perturbations of pre-existing ROS reactions could influence coupled reaction pathways over time, although the underlying mechanism remains unresolved. A mechanistic interpretation based on radical pair spin dynamics and secondary ROS cross-reactions is proposed, while excluding direct high-energy radiolytic pathways as an explanation. The findings are therefore considered within an exploratory, hypothesis-generating framework rather than as evidence of a demonstrated amplification mechanism. Although the observed temporal behavior of the generated ROS raises the possibility that weak ELF-EMF-associated perturbations could influence ROS dynamics in more complex systems, extrapolation to biological systems or human health remains speculative and requires direct experimental investigation. Further studies are required to evaluate the mechanistic basis and biological relevance of this framework. Reactive oxygen species (ROS) are highly reactive molecules that play important roles in both normal biology and disease. We investigated whether long-term exposure of ultrapure water to an extremely low-frequency electromagnetic field (ELF-EMF; 50 Hz, 1 mT) influences the production of three common ROS: hydroxyl radicals (•OH), superoxide radicals (O2•−), and hydrogen peroxide (H2O2). Over 1 year, continuously exposed water samples consistently showed higher ROS levels than matched non-exposed samples. The difference between exposed and non-exposed samples increased with time and showed an accelerating pattern that was well described empirically by an exponential function. This finding describes the observed pattern but does not by itself demonstrate that ROS were being amplified through an autocatalytic mechanism. The fastest increase was observed for •OH radicals, followed by O2•− radicals and H2O2, indicating different temporal behaviors among the three ROS species within the coupled chemical system. These observations are compatible with the possibility that small changes in existing ROS-generating or ROS-consuming reactions could become progressively detectable over time, but the underlying mechanism remains unresolved. Because ELF-EMFs do not carry enough energy to break covalent chemical bonds directly, our findings are not readily explained by direct energy-driven bond breaking or radiolysis and may instead be compatible with subtle modulation of pre-existing chemical processes. A possible explanation involves magnetic field effects on short-lived radical pairs, which may slightly alter reaction pathways and, over long periods, potentially influence ROS concentrations through coupled reactions. However, this remains a hypothesis rather than a demonstrated mechanism. Our study is therefore best regarded as an exploratory hypothesis-generating investigation. Since the experiments were performed in ultrapure water, further studies are needed to determine whether similar effects occur in living systems, where antioxidant defenses, enzymes, cellular compartmentalization, and other regulatory processes may substantially modify or prevent such responses.