The epiphytic lichen (IAEA-336) was collected from areas in Portugal remote from pollution sources. These areas included Gavião (center of Portugal), Ourique and Serra do Cladeirão (south of Portugal). The lichen was harvested from both the Cistus ladanifer and Quercus species of tree. About 25 kilograms were collected, separated from debris and other epiphytic lichen species by visual inspection, then washed in deionized water and oven-dried at 40 °C for 24 hours. The lichen was ground using a Teflon “Mikro-dismembrator” mill. The final material was passed through a 125 μm sieve and mixed in a rotating plastic drum. This material was γ-sterilized to ensure long-term stability of the material by inhibiting microbial action.
| Analyte | Value | Unit | 95% C.I. | N | R/I/C |
| Al | 680 | mg/kg | 570 - 790 | 15 | I |
| As | 0.63 | mg/kg | 0.55 - 0.71 | 17 | R |
| Ba | 6.4 | mg/kg | 5.3 - 7.5 | 11 | R |
| Br | 12.9 | mg/kg | 11.2 - 14.6 | 18 | R |
| Cd | 0.117 | mg/kg | 0.100 - 0.134 | 14 | I |
| Ce | 1.28 | mg/kg | 1.11 - 1.45 | 13 | R |
| Cl | 1900 | mg/kg | 1600 - 2200 | 13 | I |
| Co | 0.29 | mg/kg | 0.24 - 0.34 | 19 | R |
| Cr | 1.06 | mg/kg | 0.89 - 1.23 | 22 | I |
| Cs | 0.11 | mg/kg | 0.097 - 0.123 | 13 | R |
| Cu | 3.6 | mg/kg | 3.1 - 4.1 | 21 | R |
| Eu | 0.023 | mg/kg | 0.019 - 0.027 | 9 | I |
| Fe | 430 | mg/kg | 380 - 480 | 35 | R |
| Hg | 0.2 | mg/kg | 0.16 - 0.24 | 15 | R |
| K | 1840 | mg/kg | 1640 - 2040 | 24 | R |
| La | 0.66 | mg/kg | 0.56 - 0.76 | 12 | R |
| Lu | 0.0066 | mg/kg | 0.0042 - 0.0090 | 5 | I |
| Mn | 63 | mg/kg | 56 - 70 | 29 | R |
| Na | 320 | mg/kg | 280 - 360 | 20 | R |
| Nd | 0.6 | mg/kg | 0.42 - 0.78 | 5 | I |
| P | 610 | mg/kg | 490 - 730 | 12 | I |
| Pb | 4.9 | mg/kg | 4.3 - 5.5 | 23 | I |
| Rb | 1.76 | mg/kg | 1.54 - 1.98 | 16 | I |
| Sb | 0.073 | mg/kg | 0.063 - 0.083 | 12 | R |
| Sc | 0.17 | mg/kg | 0.15 - 0.19 | 13 | I |
| S | 0.22 | mg/kg | 0.18 - 0.26 | 12 | R |
| Sm | 0.106 | mg/kg | 0.092 - 0.120 | 15 | R |
| Sr | 9.3 | mg/kg | 8.2 - 10.4 | 19 | R |
| Tb | 0.014 | mg/kg | 0.012 - 0.016 | 7 | I |
| Th | 0.14 | mg/kg | 0.12 - 0.16 | 16 | R |
| V | 1.47 | mg/kg | 1.25 - 1.69 | 8 | I |
| Yb | 0.037 | mg/kg | 0.025 - 0.049 | 5 | I |
| Zn | 30.4 | mg/kg | 27.0 - 33.8 | 38 | R |
(Value) Concentration calculated as a mean of the accepted laboratory means
(N) Number of accepted laboratory means which are used to calculate the recommended or information values and their respective confidence intervals
(R/I/C) Classification assigned to the property value for analyte (Recommended/Information/Certified)
The values listed above were established on the basis of statistically valid results submitted by laboratories which had participated in one or more international intercomparison exercises organized by the Chemistry Unit, IAEA Laboratories, Seibersdorf. The details concerning the criteria for qualification as a recommended or information value can be found in the respective report (attached).
