Electrochemical Correction of the Redox Potential of Potable Water and Its Quality Evaluation by Animal Test Objects

In recent years, great attention is paid to such a potable water quality characteristic as the redox potential. Water has reductive properties, if the redox potential has negative values, and oxidative properties in the case of its positive values. According to the Nernst equation, this changes water pH, which may significantly differ from potable water pH approved by regulatory documents. Since the state of the internal medium of a human organism strongly depends on the potable water quality, the effect of water with positive and negative redox potentials on animal test organisms with different sensitivity ( Ceriodaphnia affinis , Hydra attenuate , and also aquarium fishes Brachidanio rerio ) has been estimated in this study. It has been shown that the most toxic medium for all the test objects is the anolyte with pH of 3.6 and a redox potential of +520 mV (100% death of all the test objects). This seems to be due to low pH of water as confirmed by the fact that 100% survival of all the organisms is observed, when anolyte pH is corrected to neutral values. The catholyte obtained at 200 mA with a redox potential of –600 mV and pH of 10.6 causes 10–20% death of test organisms. The highest sensitivity is exhibited by Ceriodaphnia affinis with 20% death of all the species. Electrotreatment at 100 mA causes only 10% death of Ceriodaphnia affinis , but the other organisms exhibit tolerance to this aqueous medium.