SEASONAL DYNAMICS OF THE CONTENT OF NITROGEN-CONTAINING COMPOUNDS A STEM IN THE WATER OF THE RIVER STUBELKA

Abstract

The most common pollutants of aquatic ecosystems are inorganic nitrogen compounds (NH4+, NO2¯ and NO3¯). The main sources of their entry into water bodies are an increase in the volume of sewage discharge from treatment facilities, the activities of enterprises, animal complexes, the peculiarities of communal and agricultural management, the growth of the level of urbanization, atmospheric precipitation, life processes and the death of hydrobionts. The purpose of the research is to determine the content of nitrogen compounds in the water of the Stubelka River. The article analyzes the seasonal dynamics of the content of nitrogen-containing compounds, temperature, pH, dissolved oxygen, HSC, BSC5 in the water of the Stubelka River. It was found that the concentration of ammonium nitrogen varies from 2.185 mg/dm3 (December) to 0.051 mg/dm3 (May), nitrites from 0.026 mg/dm3 (September) to 0.181 mg/dm3 (November), nitrates from 6.246 mg/dm3 (July ) to 0.133 mg/dm3 (January). Exceeding the maximum permissible concentrations of ammonium nitrogen in the water of the Stubelka River by 1.16–4.37 times (October, December), and nitrite by 2.26 (November). The content of nitrates during the entire period of the study does not exceed permissible values. A shift in the balance in the ammonium ↔ nitrite ↔ nitrate system was shown in the direction of nitrification (June–August, November, February–May) and ammonification (September, October, December, January), which confirms the arrival of nitrogen-containing compounds from diffuse (NH4+<NO3¯) and point (NH4+>NO3¯) sources. Seasonal changes in water temperature, pH, and dissolved oxygen were established (in summer – 19–24° C, 6.66–7.30, 5.70–8.38 mgO2/dm3; in autumn – 11–13° C, 6.91–7.30, 6.35–8.47 mgO2/dm3; in winter – 0–2o C, 8.06–10.50, 6.80–7.14 mgO2/dm3; in spring – 3–15o C, 7.66–10.3, 6.80–7.28 mgO2/dm3). The content of HSK varies from 10 mgO2/dm3 (May) to 44 mgO2/dm3 (January), and BSK5 – from 0.50 mgO2/dm3 (October, December, February) to 2.26 mgO2/dm3 (August). Seasonal dynamics of the content of nitrogen-containing compounds in the water of the Stubelka River reflects the state of the water ecosystem and allows us to find out the main processes of changing its stability.