The radioactive contamination study in south-western Greenland tundra in 2012-2013.

The paper presents results of the radioecological investigation carried out in south-western Greenland shoreline. There were examined over 50 samples of lichens and mosses collected from 7 locations during two scientific expeditions conducted in the summer of 2012-2013. The levels, trends and the most likely origin were determined for following natural and artificial radionuclides: Sr, Cs, Th, U, Pu and Am. The radioactive pollution was found as relatively low, reaching the maximum values at: 25.3 ± 2.04 Bq/kg for Sr, 293 ± 27 Bq/kg for Cs, 4.01 ± 0.13 Bq/kg for Pu, 0.1381 ± 0.0070 Bq/kg for Pu and 1.90 ± 0.21 Bq/kg of Am, 9.15 ± 0.48 Bq/kg for Th, 25.1 ± 1.2 Bq/kg for Th, 7.5 ± 1.5 Bq/kg for U and 7.26 ± 0.80 Bq/kg for U. Both activity and mass isotopic ratio assays revealed dominant contribution of the global fallout + SNAP 9A on the presence of plutonium isotopes and Am in Greenland tundra. However, noticeable deviations of Am/Pu and to a lesser extend of Pu/Pu ratios from the GF level have been observed. The origin of Cs was evidently connected with the coexistence of global and Chernobyl fallout, while the presence of Sr was caused by nuclear weapon tests and affected by leaching process. The seaborne signature of uranium isotopes was manifested in research material as well.