ATMOSPHERIC BACKGROUND DEPOSITION OF HEAVY-METALS IN DENMARK MONITORED BY EPIPHYTIC CRYPTOGAMS

Samples of a moss (Hypnum cupressiforme Hedw.) and of two lichens (Hypogymnia physoides (L.) Nyl. and Lecanora conizaeoides Nyl. ex Cromb.) were collected from the trunks of beech (Fagus silvatica L.) at 21 rural sites throughout Denmark. The samples were analysed for heavy metal content. The concentration of Cd, Cr, Cu, Ni, Pb, V and Zn in the plant material reflected the regional atmospheric deposition of these elements, but the content of Fe and Mn did not reflect atmospheric deposition. The three epiphytic species all showed the same regional variation in metal content. The concentration in Hypnum was usually the highest, followed by Hypogymnia and Lecamora in decreasing order. The concentration of most elements increased approximately 1.5 times from north-western Denmark to eastern and south-eastern Denmark. It was concluded that this gradient might result from a N-S gradient, modified by the superimposition of local pollution in the region of the Sound (Oresund).