One of the logical reasons for the study of nitrogen is the toxicity of its various forms. Their effect on the natural aquatic environment is very different and depends on the amount and structure of organic radicals associated with amine nitrogen. The difference of the effect of amines of natural origin (diethylamine - DEA) and synthetic origin (1-naphtylamine - 1-NA, diphenylamine - DPA and cetyltrimethylammonium - CTMA) on the processes of ammonia oxidation has been investigated. The maximum allowable concentration (MAC) for synthetic amines and for natural origin amines differs by almost two orders of magnitude. Both natural and synthetic amines affect oxidation-reduction processes caused by the activity of bacterial enzymes, even within MAC values. In the case of 1-NA, the inhibitory effect is associated with a toxic effect, whereas for DEA this effect is doubled (due to a toxic effect, as well as from the amine-bound carbon). CTMA also has an impact on the inhibition of processes. But in the presence of anionic surfactants (egg, lauryl sulfate-LS) in an aqueous medium, the effect of CTMA is clearly reduced. Conversely, the presence of CaCO3 particles reduces the ability of anionic organic substances to decrease the effect of cationic ones. Typically, the amines, arising from the decomposition of organic materials of natural origin, have less toxicity and lower MAC than those of synthetic origin. It is important to note here that laboratory models are sensitive even at concentrations below the MAC. Because of this, MAC can not be perceived as absolute values and only meaning within certain limits.