Hydrogen peroxide is an unstable oxidizer that occurs naturally in the marine environment. In surface ocean waters, H2O2 concentration oscillate from 10-2 to 10-1 mM. Its transient character in sea water is determined mainly by the protonation of the superoxide anionic radical (O2•-), and the disproportionation of the hydroperoxyl radical (HO2•). Apart from the H2O2 present and generated in the marine environment, it is used in aquaculture in higher concentrations. There is a lot of data on the use of this compound in the fish farming industry. It is an agent against various groups of pathogenic organisms, mainly outer parasites, bacteria and fungi. However, despite the rapid decomposition of hydrogen peroxide in the presence of organic material and aeration, concentration values and toxicity to fish are determined by the sensitivity of a given species.
The methodology for determining the concentration of H2O2 covers: photometric-DPD method, colorimetric method, iodometric techniques, luminol chemiluminescence, and more.