Assessment of the Level of Pollution of Glacial and Non-Glacial Rivers of the Central Caucasus Based on the Results of Five-Year Monitoring

An assessment of the pollution of glacial and non-glacial rivers of the Central Caucasus for the observation period 2020–2024 was conducted. By comparing with established maximum permissible concentrations (MPCs) for NO2‒, NO3‒, and NH4+, the main pollutants were identified. The content of inorganic nitrogen compounds was determined using chemical analysis methods. Concentration levels of the components in the waters of the following six glacial rivers: the Urukh, Cherek, Baksan, Chegem, Malka, and Terek, as well as in the waters of three non-glacial rivers—Kurkuzhin, Shalushka and Nalchik—are presented. The most polluted watercourses and their flow frequency were established. The results indicate that the range of concentrations of inorganic nitrogen compounds in the waters of glacial-fed rivers varied widely. Interannual and interseasonal variability in their content was noted. The main pollutants in the waters of glacial-fed rivers (NO2‒, NH4+) and in the waters of non-glacial origin (NO2‒, NO3‒, and NH4+) were identified. Generally, there is a tendency for the concentration values of inorganic nitrogen compounds to increase towards the lower reaches of the studied rivers.