Variation of metal concentrations in water samples is presented in Figures 1 and 2. Descriptive statistics are presented in Table 3. Water quality assessment with regard to heavy metals was based on the recommended values of the Albanian legislation, respectively Decision no. 379, dated: 25.05.2016 as well as on the WHO guidelines (WHO 2022, Guidelines for Drinking Water Quality).
Table 3
Descriptive statistics of metal concentrations
| Al | 20 | 0 | 41.7 | 10.3 | 46.2 | 7.5 | 14.4 | 26.3 | 50.8 | 209.8 |
| Zn | 20 | 0 | 5.46 | 1.80 | 8.06 | 0.04 | 0.75 | 1.57 | 8.97 | 24.71 |
| Fe | 20 | 0 | 7.41 | 1.76 | 7.87 | 0.00 | 0.10 | 4.10 | 16.58 | 21.50 |
| Cu | 20 | 0 | 8.69 | 1.29 | 5.75 | 0.90 | 4.38 | 7.69 | 12.95 | 20.38 |
| Cr | 20 | 0 | 1.75 | 0.21 | 0.93 | 0.47 | 1.18 | 1.62 | 2.39 | 4.53 |
| Mn | 20 | 0 | 0.42 | 0.13 | 0.60 | 0.00 | 0.07 | 0.15 | 0.50 | 2.00 |
| Ni | 20 | 0 | 18.07 | 4.62 | 20.66 | 1.55 | 6.44 | 9.63 | 22.03 | 89.87 |
| Pb | 20 | 0 | 2.13 | 0.56 | 2.50 | 0.09 | 0.97 | 1.71 | 2.15 | 12.11 |
| Cd | 20 | 0 | 0.076 | 0.006 | 0.026 | 0.05 | 0.06 | 0.065 | 0.10 | 0.13 |
| Al | 20 | 0 | 41.7 | 10.3 | 46.2 | 7.5 | 14.4 | 26.3 | 50.8 | 209.8 |
| Zn | 20 | 0 | 5.46 | 1.80 | 8.06 | 0.04 | 0.75 | 1.57 | 8.97 | 24.71 |
| Fe | 20 | 0 | 7.41 | 1.76 | 7.87 | 0.00 | 0.10 | 4.10 | 16.58 | 21.50 |
| Cu | 20 | 0 | 8.69 | 1.29 | 5.75 | 0.90 | 4.38 | 7.69 | 12.95 | 20.38 |
| Cr | 20 | 0 | 1.75 | 0.21 | 0.93 | 0.47 | 1.18 | 1.62 | 2.39 | 4.53 |
| Mn | 20 | 0 | 0.42 | 0.13 | 0.60 | 0.00 | 0.07 | 0.15 | 0.50 | 2.00 |
| Ni | 20 | 0 | 18.07 | 4.62 | 20.66 | 1.55 | 6.44 | 9.63 | 22.03 | 89.87 |
| Pb | 20 | 0 | 2.13 | 0.56 | 2.50 | 0.09 | 0.97 | 1.71 | 2.15 | 12.11 |
| Cd | 20 | 0 | 0.076 | 0.006 | 0.026 | 0.05 | 0.06 | 0.065 | 0.10 | 0.13 |
Figure 1
Variation of metals in water samples.
Figure 2
Confidence intervals of metals in selected samples.