engleski

Influence of dissolved oxygen on nitrates concentration in Zagreb aquifer

Nitrates present one of the most common and widespread groundwater pollutants in the world. Although there are numerous potential sources of nitrates, lot of studies showed high correlation between agriculture and the concentration of nitrates in groundwater. Nitrates are defined as one of the five main groups of contaminants in the study area. Zagreb aquifer is designated as part of the country`s strategic water reserves, protected by the Croatian State. It is the main source of potable water for the inhabitants of the City of Zagreb and Zagreb County. Nitrates concentration depend on the aerobic and anaerobic conditions in the aquifer. Even though there are several indicators of the aerobic and anaerobic conditions in the groundwater, concentrations of dissolved oxygen present the most important one. Most research has shown that the boundary among aerobic and anaerobic conditions is between 1 and 2 mg l‐1 O2. The goal of this work was to estimate the influence of dissolved oxygen on nitrates concentration using parametric (Pearson) and nonparametric (Spearman) correlation coefficients. T‐test was used for the calculation of correlation coefficients statistical significance (α=0.05). Chemical substance analysed mostly from national monitoring programme of the Croatian Waters, for 166 observation wells were analysed. Analyses mostly date from 1991 to 2015. Both correlation coefficients showed that there is good to very good positive, statistically significant correlation between two variables what indicates that natural conditions in the Zagreb aquifer have influence on the stability of nitrates concentration in groundwater.

Dissolved oxygen; nitrates; Zagreb aquifer; correlation

nije evidentirano