THE EVALUATION OF NUTRIENTS CONCENTRATIONS VARIABILITY IN THE NER RIVER

The concentrations of nitrogen and phosphorus often decide on the final outcome of the physicochemical status classification in the lowland river catchments located in the agricultural landscape. The study attempts to evaluate the changes in the concentrations of nutrients in the Ner river in the years 2000–2006. In the first step of the work, minimum, maximum and average concentrations of nitrogen and phosphorus were calculated. Then the variability of the nutrients concentrations were assessed. The analysis of the dynamics of nitrogen and phosphorus concentration in the water were carried out in relation to hydro-meteorological conditions, conducted water and wastewater management and land use. It was observed that the phosphate concentration in the Ner river was characterized by a marked seasonality. The highest concentrations occurred in summer and autumn and the lowest in the spring months. It was found that in 2000–2006 there was a significant relationship between phosphates and water temperature and hydrological conditions. The analyzes carried out showed that the concentration of nitrate and nitrate nitrogen were characterized by a positive trend, while phosphates and total phosphorus showed a negative trend.