Table 2.
Levels of 24 selected elements measured in propolis along with mean, standard deviations (SD), and relative standard deviation (%RSD) values, calculated for each year separately and all samples in total; 1, 2, 3—samples collected in 19 May, 23 June and 8 July 2018, respectively; 4, 5, 6—samples collected in 19 May, 1 June and 29 June 2019, respectively. Values of mean and SD are expressed in mg/kg, QL—quantification limit.
| Element | 1 | 2 | 3 | Year 2018 | 4 | 5 | 6 | Year 2019 | Years 2018 and 2019 | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| [mg/kg] | Mean + SD | %RSD | [mg/kg] | Mean + SD | %RSD | Mean + SD | %RSD | |||||
| Ag | <QL | 0.01 | <QL | 0.003 ± 0.006 | 173.21 | <QL | 0.07 | <QL | 0.009 ± 0.016 | 173.21 | 0.009 ± 0.016 | 177.76 |
| Al | 140.00 | 120.00 | 120.00 | 126.67 ± 11.55 | 9.12 | 93.00 | 97.00 | 69.00 | 86.33 ± 15.14 | 17.54 | 86.33 ± 15.14 | 23.63 |
| As | 0.11 | 0.06 | 0.08 | 0.09 ± 0.03 | 26.98 | 0.06 | 0.06 | 0.05 | 0.056 ± 0.009 | 16.20 | 0.056 ± 0.01 | 32.40 |
| Ba | 3.90 | 2.60 | 2.90 | 3.13 ± 0.68 | 21.72 | 1.50 | 1.80 | 1.70 | 1.67 ± 0.15 | 9.17 | 1.67 ± 0.15 | 38.19 |
| Ca | 500.00 | 560.00 | 300.00 | 453.33 ± 136.14 | 30.03 | 300.00 | 220.00 | 360.00 | 293.33 ± 70.24 | 23.94 | 293.33 ± 70.24 | 34.99 |
| Cd | 0.05 | 0.04 | 0.03 | 0.043 ± 0.01 | 23.26 | 0.03 | 0.08 | 0.03 | 0.032 ± 0.006 | 19.52 | 0.032 ± 0.0184 | 25.56 |
| Co | 0.13 | 0.10 | 0.20 | 0.14 ± 0.05 | 35.80 | 0.10 | 0.10 | 0.08 | 0.09 ± 0.01 | 13.45 | 0.09 ± 0.01 | 36.95 |
| Cr | 0.69 | 0.72 | 0.54 | 0.65 ± 0.10 | 14.84 | 0.28 | 0.41 | 0.25 | 0.31 ± 0.09 | 27.14 | 0.31 ± 0.09 | 41.84 |
| Cu | 2.00 | 1.40 | 1.40 | 1.6 ± 0.35 | 21.65 | 3.00 | 1.10 | 0.98 | 1.69 ± 1.13 | 66.92 | 1.69 ± 1.13 | 45.62 |
| Fe | 150.00 | 160.00 | 120.00 | 143.33 ± 20.81 | 14.52 | 97.00 | 84.00 | 76.00 | 85.67 ± 10.60 | 12.37 | 85.67 ± 10.60 | 30.45 |
| K | 730.00 | 1100.00 | 470.00 | 766.67 ± 316.60 | 41.30 | 610.00 | 600.00 | 730.00 | 646.67 ± 72.34 | 11.19 | 646.67 ± 72.34 | 30.52 |
| Mg | 110.00 | 140.00 | 76.00 | 108.67 ± 32.02 | 29.47 | 100.00 | 64.00 | 110.00 | 91.33 ± 24.19 | 26.49 | 91.33 ± 24.19 | 27.10 |
| Mn | 7.90 | 8.30 | 6.40 | 7.533 ± 1.002 | 13.30 | 5.00 | 9.70 | 5.90 | 6.87 ± 2.49 | 36.33 | 6.87 ± 2.49 | 24.15 |
| Mo | 0.07 | 0.13 | 0.04 | 0.08 ± 0.05 | 58.10 | 0.04 | 0.05 | 0.06 | 0.05 ± 0.01 | 26.01 | 0.05 ± 0.01 | 51.43 |
| Na | 30.00 | 20.00 | 29.00 | 26.33 ± 5.51 | 20.91 | 23.00 | 20.00 | 14.00 | 19.00 ± 4.58 | 24.12 | 19.00 ± 4.58 | 26.71 |
| Ni | 0.53 | 0.86 | 0.47 | 0.62 ± 0.21 | 33.87 | 0.25 | 0.40 | 0.36 | 0.34 ± 0.08 | 23.07 | 0.37 ± 0.08 | 43.92 |
| P | 230.00 | 160.00 | 110.00 | 166.67 ± 60.28 | 36.17 | 300.00 | 190.00 | 210.00 | 233.33 ± 58.59 | 25.11 | 233.33 ± 58.59 | 32.25 |
| Pb | 1.00 | 0.68 | 0.74 | 0.817 ± 0.17 | 21.09 | 0.50 | 0.60 | 0.44 | 0.51 ± 0.08 | 15.75 | 0.51 ± 0.08 | 30.30 |
| S | 270.00 | 320.00 | 160.00 | 250 ± 81.86 | 32.74 | 180.00 | 200.00 | 220.00 | 200.00 ± 20.00 | 10.00 | 200.00 ± 20.00 | 26.63 |
| Sb | 0.04 | 0.04 | 0.05 | 0.042 ± 0.002 | 5.46 | 0.04 | 0.03 | 0.08 | 0.031 ± 0.005 | 17.07 | 0.031 ± 0.005 | 19.64 |
| Se | 0.08 | 0.05 | 0.04 | 0.057 ± 0.0 | 37.96 | 0.03 | 0.05 | 0.04 | 0.034 ± 0.008 | 19.87 | 0.038 ± 0.008 | 37.12 |
| Si | 170.00 | 160.00 | 140.00 | 156.677 ± 15.28 | 9.75 | 97.00 | 110.00 | 96.00 | 101.00 ± 7.81 | 7.73 | 101 ± 7.815 | 25.12 |
| V | 0.39 | 0.27 | 0.26 | 0.317 ± 0.07 | 23.59 | 0.20 | 0.22 | 0.15 | 0.19 ± 0.04 | 18.98 | 0.19 ± 0.04 | 32.95 |
| Zn | 19.00 | 12.00 | 11.00 | 14 ± 4.36 | 31.13 | 15.00 | 13.00 | 12.00 | 13.33 ± 1.53 | 11.46 | 13.33 ± 1.53 | 21.54 |