Radioactive concentrations of the Livingston Island soils (Antartica). Dosimetry considerations
ABSTRACT The radioactive concentrations of natural and man-made (90Sr and 137Cs) emitters were studied in soil samples collected from an area of 2.3 km2 around the Spanish Antarstic Base on Livingston Island in the South Shetlands.The levels of radiation detected, for natural radioisotopes, as well as consequently the measured levels of effective dose equivalent rate, are of the order of half the values commonly assigned as world averages for these magnitudes.
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ABSTRACT: There are few data reported on radionuclide contamination in Antarctica. The aim of this paper is to report 137Cs, 90Sr and 238,239+240Pu and 40K activity concentrations measured in biological samples collected from King George Island (Southern Shetlands, Antarctica), mostly during 2001–2002. The samples included: bones, eggshells and feathers of penguin Pygoscelis papua, bones and feathers of petrel Daption capense, bones and fur of seal Mirounga leonina, algae Himantothallus grandifolius, Desmarestia anceps and Cystosphaera jacquinotii, fish Notothenia corriceps, sea invertebrates Amphipoda, shells of limpet Nacella concina, lichen Usnea aurantiaco-atra, vascular plants Deschampsia antarctica and Colobanthus quitensis, fungi Omphalina pyxidata, moss Sanionia uncinata and soil. The results show a large variation in some activity concentrations. Samples from the marine environment had lower contamination levels than those from terrestrial ecosystems. The highest activity concentrations for all radionuclides were found in lichen and, to a lesser extent, in mosses, probably because lichens take up atmospheric pollutants and retain them. The only significant correlation (except for that expected between 238Pu and 239+240Pu) was noted for moss and lichen samples between plutonium and 90Sr. A tendency to a slow decrease with time seems to be occurring. Analyses of the activity ratios show varying fractionation between various radionuclides in different organisms. Algae were relatively more highly contaminated with plutonium and radiostrontium, and depleted with radiocesium. Feathers had the lowest plutonium concentrations. Radiostrontium and, to a lesser extent, Pu accumulated in bones. The present low intensity of fallout in Antarctic has a lower 238Pu/239+240Pu activity ratio than that expected for global fallout.Polar Biology 08/2008; 31(9):1081-1089. DOI:10.1007/s00300-008-0449-5 · 2.07 Impact Factor
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ABSTRACT: A study was carried out of the physico-chemical characteristics of the different layers of ice to a depth of 8.32 m in the Hurd glacier on Livingston Island in the South Shetland archipelago (Antarctica). No dependence on depth was observed for the pH, dry residue, or the concentrations of Ca2+, Mg2+, and K+ ions. The only dependence observed was a systematic increase in density from 0.5 to 0.85 g cm(-3) due to the greater compaction of the deeper layers. The mean annual mass balance was determined by two methods: localization of the ashes emitted by a volcano on Deception Island and by means of a Pb-210 dating method. The result in both cases was a value of 0.24 kg m(-2) yr(-1), which allowed us to date different layers of ice sampled. The mean annual Pb-210 fallout was determined to be 1.9 Bq m(-2) yr(-1). While no systematic variations in total beta activity were observed with depth, they were observed for total alpha and residual beta activities in the said ice layers. Copyright (C) 1996 Elsevier Science LtdApplied Radiation and Isotopes 08/1996; 47:811-819. DOI:10.1016/0969-8043(96)00033-4 · 1.06 Impact Factor
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ABSTRACT: The temporal arrangement of the ice layers that are produced in ecosystems with perpetual snows form situations that greatly favour the study of the temporal evolution of the radioactive fallout that occurs in the said zones, whether this fallout is natural or artificial in origin. This allows one to investigate the causes of the fallout and the mechanisms transporting the radionuclides involved from their source point to the study zone, as well as their subsequent behaviour in that zone. There are special difficulties involved in this type of study in Antarctica. Some are of a general character deriving from the conditions of extreme climate and isolation which complicate the processes of extraction and pre-treatment of the samples. Others are directly related to the detection of the temporal evolution of the radionuclides of interest, since these generally possess very low activity levels, so that one has to collect large volumes of samples and use refined techniques of extraction and selective radiochemical concentration prior to assay. In particular, the primordial radionuclides are usually detected in Antarctic ice at lower activity levels than are found for similar latitudes in the northern hemisphere (Nijampurkar and Rao 1993), mainly because of the greater proportion of land to sea in the northern hemisphere. With respect to the deposition of artificial radionuclides, save for those from the re-entry into the atmosphere of the SNAP-9A satellite and from the French atmospheric tests in the Mururoa Atoll between 1966 and 1974, the main events responsible for global artificial radioactive contamination occurred in the northern hemisphere (Kathren 1984), with the resulting observed progressive fall in artificial radioactivity, levels from northern to southern latitudes (Baeza et al. 1996, Holm et al. 1991).Bulletin of Environmental Contamination and Toxicology 09/1999; 63(2):139-49. DOI:10.1007/s001289900959 · 1.22 Impact Factor