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

This paper reports the results of total sulphur content, photosynthetic pigments, ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) analysed in current-year needles of Norway spruce (Picea abies (L.) Karst.) in the area influenced by sulphur emissions from the Sostanj Thermal Power Plant (STPP), Slovenia, in the period 1991-2004. Ten differently polluted sampling sites in the emission area of STPP were selected. After desulphurization of emission gases from STPP total sulphur content in needles decreased and vitality parameters of needles increased. Moreover, a strong correlation between the average annual emissions of SO(2) from STPP 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 SO(2).