Biogeochemical signatures in the lichen Hypogymnia physodes in the mid Urals.
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. (234)U/(238)U 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.
Purvis
O W
OW
Department of Botany, Natural History Museum, Cromwell Road, London SW7 5BD, UK. w.purvis@nhm.ac.uk
Longden
J
J
Shaw
G
G
Chimonides
P D J
PD
Jeffries
T E
TE
Jones
G C
GC
Mikhailova
I N
IN
Williamson
B J
BJ
D016000:Cluster Analysis; D004190:Disasters / Q000706:statistics & numerical data*; D008011:Lichens / Q000737:chemistry*; D013058:Mass Spectrometry; D025341:Principal Component Analysis; D011834:Radiation Monitoring / Q000706:statistics & numerical data*; D012426:Russia; D013054:Spectrophotometry, Atomic; D014501:Uranium / Q000032:analysis*
D014501:Uranium