A STUDY OF THE AIR-POLLUTION IN THE SURROUNDINGS OF AN ALUMINUM SMELTER, USING EPIPHYTIC AND LITHOPHYTIC LICHENS

Epiphytic and lithophytic lichens are sampled in the surroundings of a n aluminium plant and analysed for 33 elements using the kg-method of neutron activation analysis. Thanks to their much higher accumulation factors, related to characteristic thallus structure and longer life, lichens are more advantageous bioindicators than, say, grasses or pine needles. In this case, a clear correlation is found between the conce ntrations in the lichens of the elements which characterise the Al pro duction process, on the one hand, and the wind rose and the distance f rom the plant, on the other. In the near vicinity of the plant (3 to 1 5 km, the area having the shape of the wind rose) epiphytic varieties, less resistant to the pollution, have died out.