Atmospheric radionuclides accumulation in supraglacial sediments and mosses on two Arctic glaciers in Svalbard

Radionuclide accumulation in glacial environments is of increasing concern due to its potential ecological implications associated with retreat of glaciers worldwide. Identifying suitable matrices for monitoring radionuclides in glacial environments is therefore important for assessing their environmental availability and potential downstream transport. This study aimed to assess the occurrence of artificial (137Cs, 239+240Pu) and natural (210Pb) radionuclides in glacier mice and cryoconite (supraglacial sediments) from Svalbard. Samples were collected from two glaciers (Longyearbreen and Foxfonna), with glacier mice present at one site. Additionally, we compared our results with activity concentration from other studies on radionuclides in cryoconite and plants on Svalbard, as well as a few available studies on glacier mice in general. Investigated radionuclides were found in both matrices, while cryoconite generally exhibited higher activity concentrations than glacier mice. The 240Pu/239Pu atomic ratios indicate that global fallout is the primary source of these isotopes. Glacier mice were created by two species of moss, Sanionia nivalis and Hygrohypnella polaris. Radionuclide concentrations in the glacier mice and cryoconite in Central Spitsbergen are lower than those previously reported for cryoconite in the Arctic. We corroborate that cryoconite is a more robust matrix for radionuclide monitoring and demonstrate that glacier mice have potential as complementary biomonitors for studies on radionuclide availability in Arctic glacial environments. The use of glacier mice as biomonitors may provide new insights into the transport, deposition, and accumulation of contaminants at glacier forefields.