# Hydrochemical Characteristics and Suitability Assessment of Groundwater Quality for Irrigation
## 3 Results and Discussion
### Hydrochemical Characteristics  
According to the ion balance error (IBE), all groundwater samples in the study area are within the limits of 5%, indicating a valid water quality analysis. According to average concentrations, ion compositions were as follows: at Nikinci and Sid locations Ca\({}^{2+}\) > Mg\({}^{2+}\) > Na\({}^{+}\) > K\({}^{+}\), at the Lacarak location Ca\({}^{2+}\) > Na\({}^{+}\) > Mg\({}^{2+}\) > K\({}^{+}\); and at Nikinci and Lacarak locations HCO\({}_{3}\)\({}^{-}\) > SO\({}_{4}\)\({}^{2-}\) > Cl\({}^{-}\) > NO\({}_{3}\)\({}^{-}\) > CO\({}_{3}\)\({}^{-}\), while at the Sid location HCO\({}_{3}\)\({}^{-}\) > Cl\({}^{-}\) > SO\({}_{4}\)\({}^{2-}\) > NO\({}_{3}\)\({}^{-}\) > CO\({}_{3}\)\({}^{-}\). Geochemical classification of groundwater was done using the trilinear Piper diagram [23], as previously presented in similar studies [24; 25]. This diagram is a common method that has distinct zones that describe the dominant cations and anions that influence the hydrochemistry of groundwater. As can be seen in Figure 2, in the cation triangle, most of the samples from the three monitoring locations belong to the Ca and no dominant water type, while in the anion triangle, all of samples belong to HCO\({}_{3}\) water type, except one sample from the Sid monitoring location. Observing the diamond field of the diagram, it can be concluded that all three locations can be classified as a Ca-Mg-HCO\({}_{3}\) hydrochemical type (only one sample from the Sid monitoring location belonged to Na-Cl type), where the alkaline earth metals Ca\({}^{2+}\) and Mg\({}^{2+}\) exceed alkali metals and the weak acid HCO\({}_{3}\)\({}^{-}\) exceeds the strong acids Cl\({}^{-}\) and SO\({}_{4}\)\({}^{2-}\)[26]. This hydrochemical type of groundwater can be related to carbonate-rich minerals in the aquifers [27]. Groundwater chemical components are characterized by water-rock interactions and chemical processes [28]. [PERSON] (1970), [29] proposed two diagrams to understand the hydrogeochemical procedures with reference to atmospheric precipitation, rock-water interaction, and evaporation. In other words, these diagrams illustrate the relationship between groundwater chemistry and aquifer lithology. As shown in Figure 3, groundwater samples from the analyzed area were plotted in the zone of evaporation dominance,  
Figure 2: Piper diagram of groundwater from monitoring locations in the Srem region. close to the rock-dominant zone. Similar results were presented by [28], suggesting that evaporation-sedimentation is the main factor affecting the chemical composition of this groundwater. Additionally, the movement toward the evaporation zone can be attributed to the lack of precipitation during the summer season, which has increased the intensity of evaporation [27]. Physical parameters such as total dissolved salts (TDS), electrical conductivity (EC) and pH value (pH) are presented for each measured well, for the period from 2011 to 2020 in Table 5. Total dissolved salts are one of the most important parameters for irrigation because they significantly impact the growth of plants and the quantity and quality of the yield. The values at all three monitoring locations do not have a wide range. Also, the amount of accumulated salt in the soil is directly dependent on the salinity of the irrigation water. Electrical conductivity is directly related to the sum of cations or anions and is strongly correlated with the dry residue, and that is the reason for the same narrow range of EC values [30]. Figure 3: Gibbs diagrams of groundwater from monitoring locations in the Srem region.