Abstract. A survey of airborne radioactive isotopes (137Cs,
238Pu, 239+240Pu, 241Am, and 210Pb) and trace metals (Pb,
Cu, Zn, Cd, Fe, Al) in tundra soils and cryoconite hole material sampled
from several locations in the Kaffiøyra region of Spitsbergen revealed
significant variability in spatial concentration. Lithogenic radionuclides
(230Th, 232Th, 234U, 238U) show less variability than
the airborne radionuclides because their activity concentrations are
controlled by mixing of local material derived from different types of
bedrock. Activity ratios of the artificial radionuclides in most cryoconite samples
differ from global fallout signatures. The contribution of radionuclides
from additional and more specific sources might be enhanced by
non-continuous exposure of cryoconite to atmospheric deposition. We assumed
that the main source of Pu, which was detected only in cryoconite samples,
is derived from nuclear tests and non-exploded weapons-grade material.
Approximately one-third of the total observed Pu activity concentration is
238Pu, most likely originating from the SNAP9A satellite re-entry,
which was powered by a 238Pu thermoelectric generator. In samples from
Waldemarbreen the influence of glacial local morphology on the capability of
cryoconite for trapping and accumulating airborne radionuclides is apparent.
Local glacial morphology plays an important role in determining the
accumulation of airborne pollutants. Trace metal concentrations in soils
were typical or slightly higher than concentrations characteristic for the
natural background; the 206Pb∕207Pb signature was also close to
the natural ratio of the parent rocks. Conversely, trace metal
concentrations in cryoconite samples (Pb and Cd) were higher than in soil
samples and exceeded natural values. Cryoconite is an effective monitor of
the spread of artificial radionuclides and heavy metals in their surrounding
environment.
Cryoconite granules are mixtures of mineral particles, organic substances and organisms on the surface of glaciers where they decrease the ice albedo and are responsible for formation of water-filled holes. The contaminants are effectively trapped in the cryoconite granules and stay there for many years. This study evaluates the contamination level of artificial and natural radionuclides in cryoconite holes from Adishi glacier (Georgia) and identifies the sources of contamination based on activity or mass ratios among artificial radionuclides. Results revealed high activity concentrations of fallout radionuclides reaching 4900 Bq/kg, 2.5 Bq/kg, 107 Bq/kg and 68 Bq/kg for 137Cs, 238Pu, 239+240Pu and 241Am, respectively. The main source of Pu is global fallout, but the low 240Pu/239Pu atomic ratios also indicated local tropospheric source of 239Pu, probably from the Kapustin Yar nuclear test site. Also, high activity ratios of 241Am/239+240Pu could originate from Kapustin Yar. The natural radionuclides originate from the surrounding rocks and were measured to control the environmental processes. 210Pb in cryoconite granules comes predominantly from the atmospheric deposition, and its activity concentrations reach high values up to 12000 Bq/kg.
The paper summarizes results of investigation of the current state of radioactive contamination on site being under consideration for planned nuclear power plant in northern Poland. Thanks to use of sequential procedure it was possible to determine activity concentrations for radioisotopes of nine elements, both natural and artificial. Results show that observed levels of radioactive contamination are rather typical for central Europe and global fallout is dominant factor of presence of artificial radionuclides. The total deposition for artificial radionuclides revealed maxima equal to 1747 ± 121 Bq/m2 for 137Cs, 3854 ± 158 Bq/m2 for 90Sr, 101 ± 23 mBq/m2 for 237Np, 57.7 ± 6.0 Bq/m2 for 241Am, 3.27 ± 0.80 Bq/m2 for 238Pu and 68.5 ± 5.0 Bq/m2 for 239+240Pu.
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