Levels and transfer of super(210)Po and super(210)Pb in Nordic terrestrial ecosystems

• Published in: Journal of environmental radioactivity 2011-05, Vol.102 (5), p.430-437
• Main Authors: Brown, JE, Gjelsvik, R, Roos, P, Kalas, JA, Outola, I, Holm, E
• Format: Article
• Language: English
• Subjects: Humus
• ISSN: 0265-931X
• DOI: 10.1016/j.jenvrad.2010.06.016

Recent developments regarding environmental impact assessment methodologies for radioactivity have precipitated the need for information on levels of naturally occurring radionuclides within and transfer to wild flora and fauna. The objectives of this study were therefore to determine activity concentrations of the main dose forming radionuclides super(210)Po and super(210)Pb in biota from terrestrial ecosystems thus providing insight into the behaviour of these radioisotopes. Samples of soil, plants and animals were collected at Dovrefjell, Central Norway and Olkiluoto, Finland. Soil profiles from Dovrefjell exhibited an approximately exponential fall in super(210)Pb activity concentrations from elevated levels in humus/surface soils to "supported" levels at depth. Activity concentrations of super(210)Po in fauna (invertebrates, mammals, birds) ranged between 2 and 123 Bq kg super(-1) d.w. and in plants and lichens between 20 and 138 Bq kg super(-1) d.w. The results showed that soil humus is an important reservoir for super(210)Po and super(210)Pb and that fauna in close contact with this media may also exhibit elevated levels of super(210)Po. Concentration ratios appear to have limited applicability with regards to prediction of activity concentrations of super(210)Po in invertebrates and vertebrates. Biokinetic models may provide a tool to explore in a more mechanistic way the behaviour of super(210)Po in this system.