Ability of metal trace elements accumulation by Lichens, Xanthoria parietina and Ramalina farinacea, in Megres area (Setif, Algeria)

The accumulating ability of the atmospheric Metal Trace Elements (MTE) of two lichenic species thalli; Xanthoria parietina and Ramalina farinacea were evaluated in the region of Megres. The recorded concentrations of MTE (Fe, Cu, Mn, Cd, and Pb) were determined by atomic absorption spectrophotometry (AASF). The ability to accumulate MTE in X. parietina thalli is considerably greater than that of the fruticulous lichen R. farinacea in all stations studied. The general pattern of the elements accumulated in the thalli of the two species in decreasing order of their concentrations was Fe> Mn> Pb> Cu> Cd. The Fe values are very high in X. parietina thalli with an average of 35237.5 ± 3394.2 mg/kg dry wt. In contrast, the Pb concentrations are high, especially in the southern station of the Megres region. The results showed that X. parietina is a hyper-accumulating species of MTE, compared to R. farinacea. This work highlights the ecological importance of this species as a stable and resistant pioneer in this fragile region.