Modeling heavy metal release in the epiphytic lichen Evernia prunastri

In this study, the release of Cu(2+) and Zn(2+) was investigated and modeled in the epiphytic lichen Evernia prunastri. Samples were incubated with solutions containing these metals at ecologically relevant concentrations (10 and 100 μM) and then transplanted to a remote area and retrieved after 1, 2, 3, 6, 12, and 18 months. The results showed that, after 12 months, all samples faced similar metal reductions of ca. 80–85%, but after this period, all the involved processes seem to be no longer capable of generating further reductions. These results suggest that the lichen E. prunastri can provide information about environmental improvements after exposure to high or very high pollution levels in a relatively short period of time.