Actinide enrichment in marine aerosols

Abstract

Previous work1–4 has shown that a small fraction of the plutonium and americium discharged into the Irish Sea from the nuclear fuels reprocessing plant at Sellafield, Cumbria (United Kingdom) has been transferred into the atmosphere and returned to land. Bubble scavenging in the water column, coupled with droplet ejection from bubbles bursting at the surface, may be involved in the transfer mechanism; other studies5–7 have shown this to be true for heavy metals. Laboratory measurements8,9 have demonstrated aerosol enrichments for radionuclides. Here we describe investigations of the sea-to-air transfer of Pu and Am. Initial results indicate that, relative to their concentrations in bulk sea water, these actinides are enriched in artificially generated marine aerosols by factors of 30–600. We believe this to be the first field study which demonstrates that bursting bubbles can contribute to enhanced actinide levels in marine air.