The hydrochemical properties of groundwater play a crucial role in crop growth and soil health, as well as the maintenance of irrigation equipment. To ensure suitable water quality for irrigation, the present study was conducted to evaluate the hydrochemical properties of irrigation groundwater in a typical agricultural region of Serbia. Groundwater was sampled at three monitoring locations in the Srem region in Republic of Serbia between 2011 and 2020. Examined parameters included electrical conductivity (EC), total dissolved salts (TDS), pH values, and the concentrations of cations (sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺) and potassium (K⁺)) and anions (bicarbonate (HCO₃⁻), chloride (Cl⁻), sulfate (SO₄²⁻), and nitrate (NO₃⁻)). Further assessment was done using three classification systems; Nejgebauer’s, the US USSL, and the FAO classification. To obtain a more detailed assessment, additional indices were included, such as Soluble Sodium Percentage (SSP), Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Permeability Index (PI), Kelly’s Ratio (KR), Magnesium Adsorption Ratio (MAR), and Total Hardness (TH). The PCA analysis detected that the concentration of K⁺, Ca²⁺, and Na⁺ in the irrigation water were lower in recent years, while the concentration of Cl⁻ was higher. The cluster analysis grouped the parameters into three clusters; I—electroconductivity, II—dry residue and HCO₃⁻, and III—other water parameters for all three monitoring localities. According to the applied classifications, the majority of underground water samples were suitable for irrigation. However, some samples fell out of the range of the first class, indicating the need for regular water quality monitoring. In light of climate changes that influence water deficiency, the urgent need for wise and sustainable water use implies the application of a comprehensive approach to irrigation water quality assessment, as shown in this study.

The Danube River plays significant role not only for preserving natural ecosystems. The aim of this paper is to examine the Middle Danube water quality in the part flowing through Serbia in section Bezdan -Banatska Palanka. Water quality data were examined for seven control points for period 2004-2018, for seven parameters: suspended solids (SS), dissolved oxygen (DO), electrical conductivity ( EC ), nitrates (NO ₃ ^– -N), total phosphorus (P _tot ), biochemical oxygen demand (BOD ₅ ) and chemical oxygen demand (COD). Data analyses included the application of ANOVA, linear regression analysis and Mann-Kendall trend test. The Mann-Kendall tests in most (32/49) cases, i.e. in 65 %, confirmed the non-existence of a significant trend. Significant downward trends were confirmed in 17 cases. Water quality improvement was confirmed at following control points: Bezdan for NO ₃ ^– -N, P _tot and BOD ₅ ; Bogojevo for NO ₃ ^– -N, P _tot , COD and BOD ₅ ; Novi Sad for P _tot , BOD ₅ and COD; Slankamen for BOD ₅ and COD; Smederevo for NO ₃ ^– -N and COD; Banatska Palanka for NO ₃ ^– -N. Slight deterioration of water quality was confirmed only in two cases, at the Zemun and Smederevo where DO was decreasing. Water quality for the examined period was stable and can be characterised as excellent and/or very good (class I or class II). Results emphasise fact that water quality trends monitoring reveals river sectors where the process of water quality degradation is ongoing. Timely detected critical river sectors can draw the attention of decision-makers, who can improve the existing legislation that would lead to water quality improvement.

With the continuous trend of urbanization, increase in industrial capacities, and expansion of agricultural areas, there is also a rise in the amount of wastewater. One of the effective and economical solutions for wastewater treatment has proven to be Constructed Wetlands (CWs). Defining the locations where CWs can be built is not an easy task and there are several criteria that need to be considered. The Geographical Information Systems (GIS) and Multi-Criteria Decision Analysis—Analytic Hierarchy Process (AHP) are combined to select CW locations. AHP is one of the most commonly used methods in many environmental decision making problems, involving various conflicting criteria. In this case, conflicts arise between the evaluation of criteria that influence the selection of CW locations. The evaluation of selected criteria and sub-criteria resulted in a suitability map indicating that the first class represents 44%, the second class 37%, and the third class 16% of the total area. The fourth and fifth classes represent 3% of the total area. The criteria with the highest significance are land use, floodplains and distance of the location from populated places. This study has important implications for sustainable wastewater management in Serbia and provides guidelines for selecting locations for CWs.

The increasingly pronounced lack of water resources and their irrational exploitation and insufficient protection, along with the unfavorable consequences of extreme climatic events, represent a limiting factor of economic development in many regions of the world, including the region of Southeast Europe. The surface waters of Vojvodina (northern Serbian province) are used for irrigation, supply of industry, tourist and sports-recreational activities and transport. Irrigation represents by far the largest consumer in the total consumption of fresh water at global scale, hence it is necessary to rationalize the quantities and monitor the quality of water used for this purpose. The study conducted a qualitative assessment of the usability of water for irrigation on three important transboundary watercourses in the period 1980-2020. All three analyzed watercourses belonged to Ca-Mg-HCO3 water type. Trend analysis of parameters important for irrigation showed mostly decreasing or values without a statistically significant trend. Agronomic classifications have indicated the existence of a danger of triggering the process of soil salinization, and refere to caution when using water from these watercourses.