Time and place changes concentration of nitrite nitrogen in the southwestern part of the Slovak Republic

Abstract

Concentrations of nitrite nitrogen in the water flow Čaradice brook were evaluated in the years 2005-2010. Čaradice brook springs in the mountains of Pohronský Inovec in the southern foot of Drienka hill and it is the right tributary of the Hron River, into which mouth near the village Kozárovce. Its length is 11.1 km. Samples of the water in longitudinal profile of the watercourse were carried out from six sampling sites, on a regular basis, in the second decade of the month. The places of taking samples were localized to include all real sources causing the pollution of watercourse. The average concentration of nitrite nitrogen during the whole period represented a value of 0.05 mg dm-3. Its share in total inorganic forms of nitrogen (N-NO3-, N-NH4+, N-NO2-) represented 1.98%. Depending on the time of sampling the lowest average concentration for the whole period was recorded in February (0.032 mg dm-3). Its highest average concentration was detected in May (0.065 mg dm-3). Seasonal dynamics regularity of concentrations of nitrite nitrogen during the whole monitored period is not reflected. Effect of sampling sites on the nitrite nitrogen concentration in the water flow was as significant as the influence of the month. In the longitudinal profile of the watercourse, we generally observed a tendency of gradual increase in the concentration from the first to the last sampling site. The lowest average concentration of nitrite nitrogen (0.025 mg dm-3) was found in the sampling site, which was located under the forest ecosystem and the highest (0.066 mg dm-3) in the sampling point located below the village Kozárovce. The most significant increase in the average concentration was found in the sampling site located under Čaradice municipalities and Kozárovce, which may indicate contamination of sewage water flow. In the regulation of the Government of the Slovak Republic No. 269/2010 Coll. the recommended value for nitrite nitrogen is 0.02 mg dm-3. Calculated values of 90-th percentile (P90) of this indicator in all sampling sites were lower than the recommended value of government regulations.

Keywords

• nitrite nitrogen
• water flow
• water quality