Heavy metal bioaccumulation in lichens from Macedonia in northern Greece

Research on lichens as biological monitoring indicators is described. The concentration of Pb, Cu, Zn and Cd in lichens from polluted and unpolluted areas of Greece were determined by atomic absorption spectrometry after acid digestion. The levels of the heavy metals in the tissues of different species are discussed. Although bioaccumulation of heavy metals depends on the degree of pollution of the given biotope, large variations were observed between different species collected from the same biotope. In areas with porphyry copper deposits, pendulous lichens hanging from trees and, to a lesser extent epiphytes, were less contaminated than epigeic or epilithic ones. Epilithic lichens accumulated larger concentrations of these metals than did epigeic lichens. Finally, the capacity of lichens to accumulate heavy metals, is compared to that of mosses and tree leaves.