Effect of industrial emissions on membrane permeability of epiphytic lichens in Northern Finland and the Kola Peninsula industrial areas

The impact of air pollution on membrane permeability of the epiphytic lichens Hypogymnia physodes and Bryoria fuscescens was studied in northern Finland and the Kola Peninsula to assess the effects of the Kola industrial emissions. The conductivity and quantity of K⁺ in leachates of the lichens were determined both as absolute and relative leakage. The K⁺ leakage from the lichens was the most sensitive indicator of membrane disturbance. Positive relationships between K⁺ leakage and decreasing distance from pollution sources and modelled atmospheric SO₂ concentrations were found and the K⁺ leakage and Cu and Ni concentrations of Scots pine bark were also highly correlated. The relative conductivity of leachates was inversely related to distance from sources, while the absolute conductivity of leachates from lichens was positively correlated with bark S. The ion leakage was higher in fruticose Bryoria fuscescens than in foliose Hypogymnia physodes, but the overall response to pollution was similar in both species. The methods used were able to identify areas of disturbed membrane function around the Kola industrial areas and local point sources in northern Finland. However, the majority of the studied sites in Finnish Lapland can be regarded as undisturbed background areas with respect to these sensitive lichens.