Speaker
Description
Despite Antarctica’s geographical isolation and protection under the Antarctic Treaty, the continent remains a recipient of global radioactive fallout originating from past atmospheric nuclear weapons tests and other events, such as the burn-up of the SNAP-9A satellite Long-lived radionuclides, including Cs-137, Sr-90, and transuranic elements such as plutonium isotopes and Am-241 persist in the Antarctic environment and can be used as tracers of environmental transport processes and food chain transfer. On the other hand, Antarctic ecosystems are also influenced by naturally occurring radionuclides originating from radioactive decay series as well as from primordial radionuclides present in the environment. These radionuclides may enter food web through atmospheric deposition, seawater, and dietary intake, and their accumulation in biological tissues can provide additional information on the natural biogeochemical processes and element cycling in polar ecosystems.
In this study, we examined material from seven pellets of the south polar skua (Stercorarius maccormicki) containing remains of predated Wilson’s storm petrels (Oceanites oceanicus), a highly migratory pelagic seabird, breeding in the Antarctic and migrating to distant wintering areas in the northern Hemisphere. The pellets were collected in the breeding areas of the skuas around Admirality Bay on King George Island, South Shetland Islands. Pellets were separated into two fractions: 1) residues of feathers, 2) bones. This allowed for comparative analysis of radionuclide accumulation across tissue types. Radiometric analyses included gamma spectrometry for gamma-emitting isotopes followed by radiochemical sequential separation ending with, alpha spectrometry for uranium, thorium, plutonium isotopes, Am-241 and liquid scintillation counting determination of Sr-90.
Assessing radionuclide loads in meso-predators such as storm-petrels provides essential data on the current radiological state of the region and the potential impact of persistent contaminants on Antarctic biota. The study contributes to our understanding of the transfer and distribution of both natural and anthropogenic radionuclides within the Antarctic food chain.