Norway spruce needles as bioindicator of air pollution in the area of influence of the Šoštanj Thermal Power Plant, Slovenia

This paper reports the results of total sulphur content, photosynthetic pigments, ascorbic acid (vitamin C) and α-tocopherol (vitamin E) analysed in current-year needles of Norway spruce (Picea abies (L.) Karst.) in the area influenced by sulphur emissions from the Šoštanj Thermal Power Plant (ŠTPP), Slovenia, in the period 1991–2004. Ten differently polluted sampling sites in the emission area of ŠTPP were selected. After desulphurization of emission gases from ŠTPP total sulphur content in needles decreased and vitality parameters of needles increased. Moreover, a strong correlation between the average annual emissions of SO2 from ŠTPP and average annual sulphur content (increase) or average annual chlorophyll content (decrease) in current-year needles was found. The results showed that spruce needles may be an useful bioindicator for detecting changes in the emission rates of SO2.