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

ABSTRACT

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 90Sr, 137Cs, 230, 232Th, 234, 238U, 238, 239+240Pu and 241Am. The radioactive pollution was found as relatively low, reaching the maximum values at 25.3 ± 2.04 Bq/kg for 90Sr, 293 ± 27 Bq/kg for 137Cs, 4.01 ± 0.13 Bq/kg for 239+240Pu, 0.1381 ± 0.0070 Bq/kg for 238Pu and 1.90 ± 0.21 Bq/kg of 241Am, 9.15 ± 0.48 Bq/kg for 230Th, 25.1 ± 1.2 Bq/kg for 232Th, 7.5 ± 1.5 Bq/kg for 234U and 7.26 ± 0.80 Bq/kg for 238U. Both activity and mass isotopic ratio assays revealed dominant contribution of the global fallout + SNAP 9A on the presence of plutonium isotopes and 241Am in Greenland tundra. However, noticeable deviations of 241Am/239+240Pu and to a lesser extend of 240Pu/239Pu ratios from the GF level have been observed. The origin of 137Cs was evidently connected with the coexistence of global and Chernobyl fallout, while the presence of 90Sr was caused by nuclear weapon tests and affected by leaching process. The seaborne signature of uranium isotopes was manifested in research material as well.