# Hydrochemical Characteristics and Suitability Assessment of Groundwater Quality for Irrigation
## 3 Results and Discussion
### Hydrochemical Characteristics
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline  & \multicolumn{4}{c}{**Nikinci**} & \multicolumn{4}{c}{**\(\boldsymbol{\hat{\text{S}}}\)id**} & \multicolumn{4}{c}{**La\(\boldsymbol{\hat{\text{c}}}\)arak**} \\ \hline
**Parameter** & **Min** & **Max** & **Mean** & **SD** & **Min** & **Max** & **Mean** & **SD** & **Min** & **Max** & **Mean** & **SD** \\ \hline Ca2\({}^{+}\) (mg/L) & 70 & 96 & 89.51 & 7.29 & 86 & 123 & 107.75 & 13.73 & 68 & 111.2 & 82.84 & 13.96 \\ Mg2\({}^{+}\) (mg/L) & 59.7 & 84 & 75.62 & 7.92 & 25.3 & 39 & 31.86 & 4.40 & 18.4 & 80.2 & 47.61 & 16.74 \\ Na\({}^{+}\) (mg/L) & 13.5 & 39.8 & 30.63 & 8.58 & 12 & 26.7 & 17.32 & 5.20 & 10.9 & 82 & 57.7 & 21.33 \\ K* (mg/L) & 0.6 & 25.5 & 4.64 & 7.61 & 0.7 & 4.08 & 1.48 & 0.97 & 0.5 & 6.24 & 1.56 & 1.69 \\ HCO3 (mg/L) & 505 & 773 & 653 & 74.22 & 378 & 460 & 404.8 & 28.92 & 564 & 700 & 591.7 & 38.68 \\ Cl (mg/L) & 9.5 & 40.2 & 30.01 & 8.29 & 13 & 38 & 26.91 & 7.63 & 6.3 & 13.3 & 9.27 & 2.29 \\ SO4\({}^{-}\) (mg/L) & 5 & 107 & 41.5 & 27.73 & 5 & 27 & 16.5 & 6.29 & 2 & 48 & 24.8 & 12.80 \\ NO3-N (mg/L) & 0.2 & 12.24 & 2.56 & 3.84 & 4.4 & 27.2 & 14.36 & 7.53 & 0.03 & 5.8 & 0.747 & 1.79 \\ EC (\(\mu\)S/cm) & 975 & 1153 & 1043.8 & 49.69 & 667 & 931 & 793.2 & 88.19 & 676 & 902 & 820.9 & 60.02 \\ TDS (mg/L) & 549 & 683 & 628.8 & 46.92 & 406 & 512 & 457.9 & 37.72 & 394 & 559 & 498 & 45.95 \\ pH value & 7.11 & 7.7 & 7.52 & 0.18 & 6.95 & 7.63 & 7.41 & 0.20 & 7.01 & 7.68 & 7.421 & 0.23 \\ \hline \end{tabular}
\end{table} 
Table 5: Analyzed parameters on the monitoring locations in period 2011–2020. Concentrations of main cations and anions are also shown in Table 5. Calcium and magnesium contribute to water hardness and in larger quantities can have a negative effect, not only on crops, but also on irrigation equipment. Values of Ca\({}^{2+}\) at all three monitoring locations were between 68 and 123 mg/L. Magnesium had a wider range, from 18.4 to 84 mg/L. Sodium as a cation, is singled out because of its effect on the soil (it causes unfavorable physical and chemical changes), especially on the soil structure when it is present in the soil in an adsorbed form. Sodium affects the dispersion of the soil, which further affects the reduction of water and air penetration into the soil. Irrigation water can be a source of excess sodium. Values of Na\({}^{+}\) were in the range of 10.9 to 82 mg/L. In the group of anions, chlorides, bicarbonate, and sulfates play dominant roles. The presence of chloride is a common phenomenon whose toxic effect is easily recognized on irrigated plants in the form of burns on the leaves or death of the tissue of the leaf itself. This ion ranged from 6.3 to 40.2 mg/L in the irrigation water. Bicarbonates had a range from 378 to 773 mg/L. Sulfates are more soluble and less likely to form residue or clog irrigation systems at lower concentrations. Values of this ion ranged from 2 to 107 mg/L. Concentrations of NO\({}_{3}\)\({}^{-}\) were in the range of 0.2 to 12.24 mg/L, which can be considered acceptable. [PERSON] and [PERSON] (1985), [PERSON] and [PERSON] (1985) state that the ideal amount of nitrogen in irrigation water should be below 5 mg/L, so that there are no side effects for sensitive crops, while for most other crops the tolerant amount of nitrogen ranges up to 30 mg/L. The analyzed hydrochemical characteristics and their values of minimum, maximum, means and standard deviations (SD) are given in Table 5 and in Appendix A. Starting from the correlation matrix of the values of 11 analyzed irrigation groundwater parameters for the 10 observed years, the initial set of variables was reduced to two main components, which explains 50.31% of the variability of the initial set of variables (Figure 4), by applying the principal component analysis (PCA) method. When looking at the years in the coordinate system determined by the main components, it can be seen that the PC1 axis separated the years according to the lower values of K\({}^{+}\) (\(-\)0.84) and Ca\({}^{2+}\) (\(-\)0.84) in water.