Karakterizacija kvaliteta vode reke Ibar u funkciji procene stanja životne sredine

Abstract

A large number of data, which were too voluminous to be single iterpreted, due to the temporal and spatial variations of the parameter values, were significantly reduced by implementing statistical methods. Basic statistical analysis enables the correct interpretation of the time series of a large number of data and implies the first and the most important step in the process of classification of the river Ibar water quality. By the correlation analysis, the level of interconnection of the parameters of water quality of the river Ibar was estimated at the measuring stations by using Pearson’s and Spirman’s correlation coefficients, where attention was paid to whether the water quality parameter follows the normal distribution or not. Factor analysis showed that the group of important factors differ among the measuring stations. At the measuring stations Batrage and Kraljevo four factors for each of the stations were set apart, describing approximately 72,94 % and 78,11 % of the total variance of the observed data, respectively, while at each of the gauge stations Rudnica, Raška and Ušće three factors were set apart describing 70,64 %, 86,94 % and 64,19 % of the total variance of observed data, respectively. Application of the cluster analysis grouped data on the basis of similar characteristics; by marking the gauge stations the three clusters were obtained - the gauge stations Raška, Kraljevo and Ušće were in one, the gauge station Batrage in another, while the gauge station Rudnica in the third. The results of objective statistical techniques identify natural grouping of parameters according to the relative similarity, showing the arrangement of the pollution sources along the river and thus clearly indicates which gauge station needs to have the monitoring process improved. By using the average values of the time series data at the gauge stations, the model for multi-criteria decision making was formed on the basis of which are defined locations of increased potential environmental risk. The results of this analysis are in accordance with the qualitatively defined tree of polluters set along the river Ibar. It is important to be pointed out that the assessment of the ecological and chemical status of water quality of the river Ibar highlights the actuality of a new approach in assessing the quality of surface water and adjustment of the national legislation in the field of water to WFD. The ecological status of the water quality of the river Ibar ascertained in 2013 was of the third class, corresponding to „moderate ecological status”, and deviating from the required „good ecological status”. In comparison to considered gauge stations Batrage, Raška and Kraljevo, the most representative for the determination of water quality in 2013 was monitoring station Raška because it was located in the middle of the river Ibar watercourse, being under the greatest load of pollutants. The ecological status of the water quality of the river Ibar in the monitoring station Raska is classified as moderate (Class III) and deviates from the required quality of water because it was determined concentrations exceeding the parameters BPK5, TOC, NH4-N and PO4-P relating to the reference values. Concentrations of the group of priority substances, cadmium, lead and mercury and their compounds, exceed the prescribed value limits EQS (Environmental Quality Standards) so it was not achieved good chemical status of water quality of the river Ibar in the monitoring station Raška. The ecosystem approach clearly indicates that the concentration of a large number of physiological parameters of the watercourse deviate from the target values, and it is urgently needed the measures to be taken in preventing pollution and improving water quality of the river Ibar as an integral part of the environment.