Trace element composition of vegetation and the possible incidence of soil contamination of samples

Samples of olive leaves, the lichen Parmelia perlata (from the same trees) and the moss Scleropodium purum were collected in relatively uncontaminated areas of Calabria and Tuscany (Italy). Total concentrations of Al, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn were determined in unwashed samples. Concentrations of lithophilic elements in mosses collected at the same samplings were higher in dry and barren environments, whereas in lichens they where significantly higher at the end of the dry season. These variations were probably due to the quantities of soil particles trapped in the samples. The normalization of raw concentrations to soil composition is advisable before making comparisons, assessing baseline concentrations and calculating patterns of trace element fallout over large areas. © 1996.