Sources and accumulation of Be-7, Pb-210 and Cs-137 isotopes in the annual needles of larch and cedar in Novy Urengoy region (Arctic part of Western Siberia)

Annual needles of larch and cedar were sampled in the tundra zone of the Arctic part of Western Siberia in order to determine Be-7, Pb-210 and Cs-137 specific activities. Higher concentrations of Cs-137 in the needles of cedar relative to the needles of larch can be associated with a clear difference in the properties of accumulation and translocation of caesium among these species. Higher concentrations of Be-7 and Pb-210 in the needles of larch relative to cedar needles and close isotopic ratios (Be-7/Pb-210) are probably due to more efficient aerosol deposition on vegetative canopies of larch.