TY - JOUR
T1 - Characterisation of airborne uranium and thorium contamination in Northern England through measurement of U, Th and 235U/238U in tree bark
AU - Bellis, D. J.
AU - Ma, R.
AU - McLeod, C. W.
PY - 2001/3/5
Y1 - 2001/3/5
N2 - Samples of tree bark were collected from four locations in Northern England (a typical rural site, a coal-fired power station, a uranium (isotopic) enrichment plant and a nuclear fuel fabrication facility), to assess the nature and extent of airborne uranium and thorium contamination. The U and Th concentrations of bark were determined by inductively coupled plasma mass spectrometry after conventional nebulisation of bark digests, whilst measurement of 235U/238U isotopic ratio utilised high efficiency nebulisation. Uranium concentrations varied between and within the sites (range, 0.01-12 μg g-1), with maximum values recorded within 1 km of the nuclear fuel fabrication plant (Springfields). In comparison, the concentration of Th in bark was low (mean, 0.018 μg g-1) at all sites with the exception of the area affected by coal combustion (0.2-0.8 μg g-1). The U/Th ratio varied from 0.5 to 3900 compared with the average crustal ratio of 0.3. Low values (<2) were recorded at the 'coal' and 'rural' sites whilst Capenhurst and Springfields showed high values indicating the relative magnitude of uranium elevation. Significant enrichment of the natural 235U/238U ratio (0.00725) was observed near the nuclear installations, in particular, the enrichment plant (Capenhurst).
AB - Samples of tree bark were collected from four locations in Northern England (a typical rural site, a coal-fired power station, a uranium (isotopic) enrichment plant and a nuclear fuel fabrication facility), to assess the nature and extent of airborne uranium and thorium contamination. The U and Th concentrations of bark were determined by inductively coupled plasma mass spectrometry after conventional nebulisation of bark digests, whilst measurement of 235U/238U isotopic ratio utilised high efficiency nebulisation. Uranium concentrations varied between and within the sites (range, 0.01-12 μg g-1), with maximum values recorded within 1 km of the nuclear fuel fabrication plant (Springfields). In comparison, the concentration of Th in bark was low (mean, 0.018 μg g-1) at all sites with the exception of the area affected by coal combustion (0.2-0.8 μg g-1). The U/Th ratio varied from 0.5 to 3900 compared with the average crustal ratio of 0.3. Low values (<2) were recorded at the 'coal' and 'rural' sites whilst Capenhurst and Springfields showed high values indicating the relative magnitude of uranium elevation. Significant enrichment of the natural 235U/238U ratio (0.00725) was observed near the nuclear installations, in particular, the enrichment plant (Capenhurst).
UR - http://www.scopus.com/inward/record.url?scp=0035062265&partnerID=8YFLogxK
U2 - 10.1039/b009220g
DO - 10.1039/b009220g
M3 - Article
C2 - 11354728
AN - SCOPUS:0035062265
SN - 1464-0325
VL - 3
SP - 198
EP - 201
JO - Journal of Environmental Monitoring
JF - Journal of Environmental Monitoring
IS - 2
ER -