Multidisciplinary analysis of Finnish esker sediment in radon source identification.
In order to define the naturally-occurring radioactive materials that are the source of radon in natural environments, a comprehensive analytical (geochemical, physical and chemical) methodology was employed to study sand samples from the Hollola esker in the city of Hollola (Lahti area, Finland). Techniques such as gamma-spectrometry, emanation measurements, sequential chemical extraction, scanning electron microscopy (SEM), electron probe microanalyses (EPMA) and inductively-coupled plasma mass spectrometry (ICP-MS) were used to determine the potential source of radon. Monazite and xenotime, uranium- and thorium-bearing minerals and potential radon sources, occurred in significant amounts in the samples and were also the main reason for the distribution of uranium and thereby radium in separate grain-size fractions. Following deposition, the esker sand has been exposed to no significant weathering, and radium has not therefore been much separated from uranium. However, considering its non-compatibility with crystal lattices, it was recognized rather in easily leachable species (44% of the total (226)Ra) than uranium (21% of the total (238)U) in our analyses. The smallest grain-size fraction of the esker sand had a higher emanation power (0.24) than the other fractions (around 0.17). Due to the small relative proportion of this fraction, however, it contributed only slightly to the total emanation (4%). The emanation power of the leachable species was about three times higher (ca. 0.20) than that of the species tightly bound to the crystal lattice (ca. 0.07).
Breitner
Dániel
D
Lithosphere Fluid Research Lab, Institute of Geography and Earth Sciences, Eötvös University, Budapest, Hungary. danielbreitner@yahoo.com
Turtiainen
Tuukka
T
Arvela
Hannu
H
Vesterbacka
Pia
P
Johanson
Bo
B
Lehtonen
Marja
M
Hellmuth
Karl-Heinz
KH
Szabó
Csaba
C
D005387:Finland; D005720:Gamma Rays; D019015:Geologic Sediments / Q000737:chemistry*; D010316:Particle Size; D011834:Radiation Monitoring; D011886:Radon / Q000032:analysis* / Q000737:chemistry; D014131:Trace Elements / Q000032:analysis
D014131:Trace Elements; D011886:Radon