Assessment of elevated radionuclide levels in soils associated with an avian colony in a high arctic environment

This article presents the results of an investigation into the occurrence of elevated levels of radionuclides in soils associated with a seabird colony in the Arctic. Soils and other materials were collected from a seabird colony (primarily composed of kittiwakes) in Kongsfjorden, located in the High Arctic archipelago of Svalbard. The samples were analyzed for a suite of gamma emitting natural and anthropogenic radionuclides, including Cs-137 and nuclides of the U-238 and Th-232 series, to establish the level of enrichment and the behavior of the radionuclides in the immediate area. The results indicate that soils near the colony exhibit enrichment factors of 8 for Cs-137, 5 for U-238 and 2 for Ra-226 compared to the nuclide content of soils from the general area. The spatial patterns of the nuclides in the soil are consistent with enrichment of the soil via run-off draining from a large accumulation of fecal and nesting material that has developed at the base of the colony. Cs-137 ingress to the soil appears to have peaked at some point in the past as patterns of enrichment at the colony are different to those exhibited by 138 U, which must be assumed to be a steady state contribution. The means of introduction of radionuclides to the colony remains unclear but the transfer of Cs-137 from the marine environment to the terrestrial environment via the food chain and deposition of feces is discussed.