## 2 Materials and Methods
### Generation of Magnetic Fields and Processing of Water Samples  
The experiments were conducted utilizing relatively weak magnetic fields, with a strength either less than or similar to those of the geomagnetic field (GMF), which typically vary between 30 and 65 \(\upmu\)T. To ensure consistency and minimize the dependence on external conditions, we employed specialized research equipment, specifically a pair of cylindrical devices designed to create a hypomagnetic environment: one was located horizontally, and another one was located vertically (Figure 1). The treatment of water samples using a CMF was conducted in a hypomagnetic environment device (similar to the one shown in Figure 1 and in [11]). This device reduced the external geomagnetic field (GMF) by up to 5000 times, ensuring the residual static field did not exceed 10 nT. Moreover, it substantially minimized alternating anthropogenic noise to a single-digit nT level, as confirmed via measurements. The device comprised three coaxially arranged cylindrical permalloy magnetic shields, each with walls of 1 mm thickness. These shields were nested within each other and equipped with closures featuring inlet ports for connecting the device to measurement equipment. The innermost shield measured 22 cm in diameter and 42 cm in length. The residual fields within the hypomagnetic environment device were precisely measured using a Mag-03 MS100 fluxgate magnetometer (Bartington, Witney, UK). A specialized electromagnetic induction coil, or solenoid, was positioned inside the device to experimentally induce a CMF. The solenoid was linked to a current source, producing a static magnetic field (SMF) of 60 \(\mu\)T, and to a low-frequency alternating signal source, creating the alternating field component with a frequency of 12.6 Hz and an amplitude of 50 nT (utilized for pre-incubating water samples). The coil specifications were as follows: 18 cm in diameter, 36 cm in length (constructed from a 720-turn, 1 mm diameter copper wire), and a resistance of 7.5 Ohm. The solenoid was used to create a uniform area of a weak CMF within the shielding unit, where the test samples were incubated. The CMF alternating component frequency was equivalent to the frequency of ion cyclotron resonance for complex hydronium ions in their hydrated form H\({}_{3}\)O\({}^{+}\) (3 H\({}_{2}\)O) (as previously shown in [11]). Water samples were exposed to a CMF in the horizontal hypomagnetic environment device in 22.5 mL optic glass spectrophotometric cubic cuvettes (Hellma Analytics, Mulhein, Germany, Cat. No. 704-001-30-10) closed with lids at room temperature (23-24 \({}^{\circ}\)C). An aliquot of a pre-treated water sample was added to a balanced salt solution (5\(\times\) concentrated Hanks' solution) and then to a suspension of intact neutrophils, incubated for 20 min at 37 \({}^{\circ}\)C at the GMF, and the intensity of cell chemiluminescence was measured as described below (see Section 2.4). The remaining part of the sample was subjected to further processing, including dilution and shaking procedures. For this, the second hypomagnetic environment device (similar to the first one but located vertically) was used. Inside this device, only an SMF was generated using a direct current source in the induction range of 10-20,000 nT. In different experiments the magnetic field strength varied: 10 nT (background near-zero field--the current source of the solenoid is turned off), as well as when current is applied to the solenoid, corresponding to the field of 200, 350, 550, 900, 1500, 2500, 5000, and 20,000 nT. Glass vials with samples were placed in special holders connected to each other using a non-magnetic rod (as shown in Figure 1b). The shaking of the samples was carried out inside (with the defined parameters of the magnetic field) and simultaneously outside (at  
Figure 1: Vertical unit for vigorous shaking of water under various magnetic conditions (GMF, near-zero magnetic field, or CMF): (**a**) general view; (**b**) schematic drawing [11]. the GMF) of the hypomagnetic device.