Rasuto zagađenje iz poljoprivrede i kvalitet površinskih voda /

A pressure problem of diffuse source pollution from agriculture to surface water quality has been studied in this dissertation. The diffuse sources of pollution have been defined and a separate category of fertilizers has been extracted as the most representative diffuse source pollution from agriculture. A change in the surface water quality has been observed in the basin of Zobnatica accumulation which is characterized by intensive agricultural production and the absence of significant concentrated pollutants. The water quality at the average values of ammonium and nitrate ions was in the I/II class, and at the average values of nitrite were mainly in the I/II class. The average concentration of orthophosphates in the last decade has reached a limit for the process of eutrophication. The average value of the total phosphorus belongs to the worst water quality class and is in the range of high concentration. Therefore, the state of accumulation has been rated as eutrophic in the terms of the risk of eutrophication. There is no statistically significant trend of increase or decrease in concentration of the nutrients. It has been concluded that future loading conditions will correspond to the period analyzed, which is negative circumstance when it comes to reducing the risk of eutrophication. The Kolenbrander method, Loss coefficient method and Pressure quantification of runoff have been used for quantification of nutrient loads from diffuse sources into water reservoir Zobnatica. During the calculation of nitrogen losses water balance has been extracted as a key factor in the leaching of nitrogen, while land usage and wind erosion have had a significant role in phosphorus losses. The input representation of nitrogen from arable land in total intake has ranged from 38.2% according to the The Kolenbrander method, to 52.2% by the Loss coefficient method to 68.4% by the Pressure quantification of runoff. The phosphorus representation has ranged from 27.2% for the Loss coefficient method to 72.7% by the Pressure quantification of runoff method. An average representation of input according to all the methods of assessment was 53% for nitrogen and 50% for phosphorus. The usage of assessment methods in quantification of diffuse source pollution from agriculture will contribute to a more precise determination of the quantity of pollutants from agriculture in the deterioration of the quality of receiving waters as well as to comprehensive consideration of the processes that make contribution to the pollution of surface waters.