The determination of the nitrogen-containing ions concentrations dynamics in the oxbow of Ishimchik to assess the impact of 2016–2017 floods

This paper presents the results of the ecological state study of oxbow Ishimchik, located in Ishim, Tyumen Region. The paper presents data on the nitrogen-containing ions concentrations dynamics in water samples of oxbow Ishimchik over the summer-autumn of 2017, the content of which is an important indicator of the water chemical composition. The presence of nitrate ions, nitrite ions and ammonia in high concentrations in the samples usually indicates that the reservoir suffers from contamination by household, agricultural and industrial waste. In 2016 and 2017 a large amount of water from heavy floods came to the oxbow, which could significantly increase the concentration of mineral forms of nitrogen. The main concern is the flood of 2016 as to stop the Ishim private sector flooding a channel was dug for discharge of floodwaters from the town-affected part into the oxbow. To determine the content of nitrogen-containing ions, the photometry method was used. The results of a chemical analysis show that the content of ammonium and ammonia cations (total), nitrite anions and nitrate anions is less than maximum permissible concentration as well as there is a change in the prevailing mineral form of nitrogen from redoxidized to oxidized.