## 5 Results and Discussions
### Cations and Anions  
The Ca\({}^{2+}\) concentrations ranged from 16 mg/L to 452.8 mg/L (median 46.6 mg/L) in January 2020 and from 48.7 mg/L to 700 mg/L (median 122 mg/L) in January 2021. The Ca\({}^{2+}\) concentrations were high in the northern, central, and southern coastal regions in January 2020 (Figure S4a) and high in the northern and southern coastal regions of the study area in January 2021, as shown in Figure S4b. The Mg\({}^{2+}\) concentrations ranged from 1.9 mg/L to 256.3 mg/L, with a median value of 19.7 mg/L, and ranged from 15 mg/L to 450 mg/L, with a median value of 64.5 mg/L, in January 2020 and January 2021, respectively. The Mg\({}^{2+}\) concentrations were high in the northern, southern, and central shoreline regions in January 2020 and in the southern and central parts of the study region in January 2021 (Figure S5a,b). The concentrations of Na\({}^{+}\) ions in groundwater in the study area ranged from 31 mg/L to 1200 mg/L, with a median concentration of 139 mg/L, in January 2020, and varied from 20 mg/L to 600 mg/L, with a median concentration of 150 mg/L, in January 2021. Higher levels of Na\({}^{+}\) were found in the southern and northern shore regions, similar to other cations (Figure S6a,b). The most abundant K\({}^{+}\) bearing silicate minerals are orthoclase, followed by microcline, nephelene, leucite, and biotite. In January 2020, the groundwater K\({}^{+}\) concentration varied from 3 mg/L to 300 mg/L, with a median of 18 mg/L. In contrast, in January 2021, it varied between 2 mg/L and 98 mg/L, with a median value of 20 mg/L in the groundwater of the study area. The spatial maps (Figure S7a,b) show that the K\({}^{+}\) concentration was very high in the southern and northern coastal regions in January 2020, while it was high in the eastern coastal regions in January 2021. Sodalite and chlorapatite are the most common Cl\({}^{-}\)-bearing minerals found as minute constituents of igneous and metamorphic rocks. Dissolved Cl\({}^{-}\) remains stable in solution forms and does not chemically react with host rock minerals. The base ion exchange process increases the Cl\({}^{-}\) value so that it exceeds the Na\({}^{+}\) level in groundwater. However, Cl\({}^{-}\) occurs in groundwater as halite (rock salt or common salt), which is NaCl salt. The Cl\({}^{-}\) values in groundwater ranged from 12 mg/L to 2880 mg/L, with a median concentration of 158 mg/L, in January 2020. The same value varied from 50 mg/L to 1674.8 mg/L, with a median concentration of 315.5 mg/L, in January 2021. High Cl\({}^{-}\) concentrations were measured on the coast of the study area during both seasons (Figure S8a,b), which could be due to seawater intrusion. The HCO\({}_{3}\)\({}^{-}\) levels in the groundwater samples rangedfrom 48 to 696 mg/L in January 2020, with a median of 190 mg/L, and from 10 mg/L to 661.4 mg/L in January 2021, with a median of 87.9 mg/L. Figure S9a,b depicts the regional distribution of HCO\({}_{3}\)\({}^{-}\) ions in the study area for January 2020 and January 2021. The central to eastern coastal regions were affected by high HCO\({}_{3}\)\({}^{-}\) levels in January 2020, while high HCO\({}_{3}\)\({}^{-}\) levels affected the southern part of the study area in January 2021. With the exception of a few groundwater samples near the coast, HCO\({}_{3}\)\({}^{-}\) was the dominant anion in the bulk of the samples. The atmospheric contact with the unconfined aquifer system, mixing of seawater with freshwater, and dissolution of carbonate minerals could be the reason for the increase in HCO\({}_{3}\)\({}^{-}\) concentration in the groundwater of the study area. SO\({}_{4}\)\({}^{2-}\) occurs in many rocks in a dilute form as metal sulfide, but it is not a major component of the Earth's outer crust. The SO\({}_{4}\)\({}^{2-}\) concentrations in groundwater in this area ranged from 12 mg/L to 750 mg/L, with a median concentration of 73 mg/L in January 2020, and from 29.8 mg/L to 493 mg/L in January 2021, with a median concentration of 143.3 mg/L.