DISPERSION AND BIOACCUMULATION OF TRACE POLLUTANTS EMITTED BY COAL-FIRED POWER PLANTS IN WEST MACEDONIA, GREECE

Coal burnt in thermoelectric plants contains a great number of trace elements and natural radionuclides, which are dispersed in the environment during coal combustion. The distribution and bioaccumulation of these trace pollutants in the northwestern part of Greece, where five lignite-fired power plants are installed, are studied. For this purpose 71 soil samples as well as 92 samples of plant organisms (trees, mosses and lichens) were examined. The determination of radionuclides, trace elements and heavy metals in all samples and then the calculation of the soil to plant Transfer Factors were conducted. The main conclusion is that there is not detectable loading of the soil caused by the trace pollutants of the fly ash emitted by the power plants. There is, however, a discernible loading in some tree species, which does not exceed the legally established limits. Mosses and lichens seem to display much higher transfer factors, confirming their ability to bio accumulate air pollutants. Finally it must be noted that the systematically high value of the ratio Ra-226/Ra-228 (similar to 1.7) in these organisms is attributed to the suspended particles of the fly ash, while the radiocesium concentrations are originated from the Chernobyl accident.