Lichens as a tool for biogeochemical prospecting

The heavy metal content in lichens and vascular plants from abandoned copper mining areas, Gerakario (Kilkis) and Megali Panagia (Chalkidiki), have been compared with metal content in soil in order to assess their efficiency to accumulate five metals (Cu, Mn, Pb, Zn, and Cr). The average metal content in the mineralized soil of Gerakario was, in descending order, Cu, Mn, Pb, Zn, and Cr, and in Chalkidiki it was Cu, Mn, Cr, Pb, and Zn. The epilithic lichens (Neophuscelia pulla) accumulated the highest amount of Cu and Pb, and Xanthoparmelia taractica accumulated the highest amount of Zn. All the lichens revealed significant (P < 0.05) correlation between Cu content in soil and that in thalli. Out of five metals studied, four (Cu, Pb, Mn, and Cr) in the epigeic lichen Cladonia convoluta, two (Cu and Mn) in both epilithic lichen N. pulla and X. taractica, and one (Pb) in vascular plant Minuartia (root) were significantly (P < 0.05) correlated between their metal content in plant tissue and in soil. Further, discoloration of C. convoluta with higher Cu concentrations adds a visible clue for biogeochemical exploration. Thus, lichens along with other symptomatic species will help in locating mining areas.