Lichen transplantation in monitoring fluoride and sulphur deposition in the surroundings of a fertilizer plant and a strip mine at Siilinjaervi

Branches of Norway spruce (Picea abies ) with epiphytic lichens were transplanted to several sites in the vicinity of a fertilizer plant and a strip mine at Siilinjaervi in Central Finland. Accumulation of fluoride, sulphur and plant nutrients N, P, K. Ca and Mg was found in Hypogymnia physodes , the concentrations depending on the distance from the emission sources. Within 4 to 6 months, the element concentrations reached the levels measured in local lichens in the same sites. The highest levels of sulphur, up to 3,000 ppm, were measured at sites close to the plant. High levels of fluorides, up to 360 ppm, were found at several sites close to both the plant and the strip mine, pointing to the importance of both those sources as emittors of fluorides. The accumulation of sulphur increased towards the autumn, while the accumulation of fluoride was highest in summer and declined in autumn. The concentration of fluoride was significantly decreased by washing the thalli. In the ultrastructure of the photobiont cells of H. physodes and Bryoria capillaris , injuries typical of exposure to sulphur developed within two weeks of transplantation, before the sulphur concentrations of the thalli were significantly elevated.