Cesium-137 Concentrations in Sediments and Aquatic Plants from the Pinios River, Thessalia (Central Greece)

The levels of radioactive contamination by artificial radiocesium (¹³⁷Cs) were evaluated in sediments and the commonest species of water plants. Specimens were collected from a range of biotopes along the Pinios River and its tributaries, during the years 1998 and 2010. The ¹³⁷Cs concentrations within the above period clearly indicate that this radionuclide still decrease in the River Pinios. A marked decrease is also observed in comparison to our previous results in 1993. ¹³⁷Cs concentration activities in the sediment are higher than in the plant material. In general, roots showed greater ¹³⁷Cs concentration than leaves, while stems showed the lowest concentration. Significant differences in ¹³⁷Cs concentrations were found among different species growing under similar environmental conditions. ¹³⁷Cs content in collected aquatic plants was in the descending order: Ceratophyllum demersum L. > Myriophyllum spicatum L. > Paspalum pasalodes Scribner > Cladophora glomerata L. > Cyperus longus L. > Potamogeton nodosus Poiret. A comparison of the studied stations indicated that the southwest side of Thessalia plain, where the first two initial sampling stations of the Pinios River and the tributaries Enipeas and Kalentzis are situated, was highly contaminated. Low ¹³⁷Cs concentrations were observed in the Titarisios tributary, originated from the northeast part of Thessalia plain, behind Mt. Olympus and the last sampling stations of the Pinios River.     

A Study of Chromium, Cooper, and Lead Distribution from Lignite Fuels Using Cultivated and Non-cultivated Plants as Biological Monitors

Concentrations of chromium, copper, and lead were determined in soil and plant specimens collected from the area of coal power plant (CPP), A. Dimitrios, the largest CPP in Greece located on the eastern part of Ptolemais basin, Macedonia. Two cultivated plants (Brassica oleracea var. capitata L. and Zea mays L.) and two non-cultivated plants (Rumex acetosa L. and Verbascum phlomoides L.) were chosen. The mean heavy metal content in the soil is described in the descending order of Cr>Pb>Cu, while for the plant material, the order was Cr>Cu>Pb. Stations in the vicinity of the CPP showed a distinctly high load of Cr in the soil, whereas for the other metals, no such correlation has been noted. Unexpectedly, high levels of chromium and copper have been found in plant samples of the control station (Grevena) where there is no significant point source of air pollution by particulate matter. In general, roots revealed a higher metal concentration than that of the other plant organs. This is more obvious in B. oleracea var. capitata for all metals studied. Thus, B. oleracea var. capitata possesses the potential for phytoremediation of soils contaminated by metals since this plant is removable together with its roots from the contaminated soil. The most contaminated leaves showed a variation in surface roughness. In V. phlomoides the non-glandular, branched candelabrum-like trichomes on the leaf epidermis effectively trapped and retained a considerable number of particles. In contrast, the waxy cuticle of R. acetosa, which forms a smooth sheet over the epidermal cells, enabled the fast removal of particles by rain or wind. In the case of Z. mays, seeds accumulated the lowest amount of all metals.     

Cesium-137 Monitoring Using Mosses from Macedonia,N. Greece

137Cs activities in mosses collected from four sites in Macedonia, N. Greece were measured for regular periods of time during the last decade following the reactor accident in Chernobyl. Samples taken in 1985 allow to determine the 137Cs contamination before the accident. A clear increase of the cesium interception was observed for about two years after the accident. Later a gradual decrease was detected which depended on various factors such as moss species, location, growth rate and substrate. Higher 137Cs amounts were observed in epilithic (Grimmia) in comparison to epiphytic or epigeic ones ( Encalypta, Tortula). From the studied biotopes Mt. Vermion presented the highest 137Cs activities. The high 137Cs values found 10 yr after Chernobyl suggest that mosses are effective and inexpensive biological detectors of the distribution and burden of fallout radionuclides.