## 3 Results and Discussion
### Physical-Chemical Parameters of Investigated Drinking Water Samples  
Among the 65 investigated water samples, 16 samples exceeded the allowed values for Fe, ammonia, and residual free chlorine (Table 3). The appearance of free chlorine residue is associated to a certain extent with the treatment of water with chlorine, its used amount being increased above the well-established minimum values in isolated cases such as the possibility of transmitting a disease through water [78]. However, the level of residual free chlorine in the water can be more definitely increased in the case of organic contamination, for example, with the droppings of farm animals [79]. The geological substrate, the level of anthropic impact, the existence of some industrial activities that use iron, and the contamination with household sewage residues can lead to increased values of iron in the water [80; 81]. Similarly, the high level of ammonium can also come from anthropogenic [82; 83] and industrial [83] activities, from animal droppings [79; 83], and from the use of chemical fertilizers for agriculture [83; 84], or it can be influenced by the pH and temperature in the environment [82]. Regarding chemical composition, the water sources from Avrig, Cisnadie, Dumbraveni, Paltinis, and Talmaciu meet all quality criteria within the studied period. Physical parameters (pH, conductivity, turbidity, and oxidizability) were found within the allowed values for the 5-year study period. Significant correlations were found between some of the chemical parameters (Table 4). The water sources (Surf and Ground) and sampling month explained 29.1% (14.4%) of the variation in the physical and chemical parameters (pseudo-F = 2, \(p\) = 0.004). The first constrained axis was the only one significant (pseudo-F = 0.7, \(p\) = 0.002), extracting 42.5% of the explained variation. This axis was defined mainly by the opposition between Surf \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \
\begin{tabular}{c} **Gross Alpha** \\ **Activity** \\ \end{tabular} &
\begin{tabular}{c} **Gross Beta** \\ **Activity** \\ \end{tabular} & **Fe** & **Cl** & **Cd** & **Mn** & pH & **Ammonia** \\ \hline Gross beta & **0.709** & & & & & & \\ activity & **(0.327)** & & & & & & \\ Nitrates & **(0.344)** & & & & & & \\ Fe & & \(-\)**0.34** & & & & & \\ Mn & **(0.285)** & & & & & & \\ pH & \(-\)**0.276** & & & & & & \\ Ammonia & & & & 0.303 & & & \\ Al & & & & 0.269 & 0.237 & & & \\ Oxidizability & & & 0.238 & & & \(-\)0.259 & 0.234 \\ Conductivity & **0.497** & **0.527** & & & & \(-\)0.263 & \\ Turbidity & & (0.257) & **0.338** & & & 0.236 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Coefficients of the correlation between radioactivity and physical and chemical parameters. Only significant (\(p<0.05\), shown in bold) or marginally significant (\(0.05<p<0.1\)) results are shown. Values given in parentheses are for data without the outliers. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Location**} & \multirow{2}{*}{**Source of Water**} & \multicolumn{3}{c}{**Chemical Parameter**} & \multirow{2}{*}{**Sampling Year**} \\ \cline{3-4}  & & **Ammonia** & **Residual Free Chlorine** & **Fe** & \\ \hline Sadu & & x & & x & 2017, 2018, 2019 \\ Tilisca & & & & x & 2018, 2021 \\ Agnita & surface & & & x & 2020 \\ Medias & & & x & & 2021 \\ Sibiu & & & x & 2018, 2019, 2021 \\ Sacel & deep & x & x & & 2018 \\ Seica-Mare & & x & x & & 2017, 2021 \\ Aciliu & subsurface & x & & & 2021 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Water sources and locations of samples showing the chemical contaminants found above the allowed concentration values. and Ground water sources but also by some monthly variation. Along this axis, turbidity and Fe showed the highest values in Surf samples, while conductivity, nitrates, ammonia, and pH showed the highest values in Ground samples (Figure 6), the response to the water source being significant for Fe, turbidity, conductivity, and nitrates (Figure 7).