Biogeochemical signatures in the lichen Hypogymnia physodes in the mid Urals

• Published in: Journal of environmental radioactivity 2006, Vol.90 (2), p.151-162
• Main Authors: Purvis, O.W., Longden, J., Shaw, G., Chimonides, P.D.J., Jeffries, T.E., Jones, G.C., Mikhailova, I.N., Williamson, B.J.
• Format: Article
• Language: English
• Subjects: Cluster Analysis; Disasters - statistics & numerical data; Fossil fuel; Geology; Hypogymnia physodes; Lichen; Lichens - chemistry; Mass Spectrometry; Principal Component Analysis; Radiation Monitoring - statistics & numerical data; Russia; Spectrophotometry, Atomic; Uranium; Uranium - analysis
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/j.jenvrad.2006.06.008

Multi-element content and uranium (U) isotopes were investigated in the lichen Hypogymnia physodes (native and transplants) sampled across a 60-km transect, centred on Karabash smelter town, from Turgoyak Lake (SW) to Kyshtym (NE) to investigate the origin of U. Kyshtym was the site of a major nuclear accident in 1957. 234U/ 238U activity ratios in native thalli sampled during July 2001 were within the natural isotopic ratio in minerals. Uranium/thorium (U/Th) ratios were higher in native thalli towards the NE (average 0.73) than those in the SW (average 0.57). Element signatures in native thalli and transplants suggest U was derived from fossil fuel combustion from Karabash and sources lying further to the east. Systematic and significant U enrichment indicative of a nuclear fuel cycle source was not detected in any sample. Element signatures in epiphytic lichen transplants and native thalli provide a powerful method to evaluate U deposition.