Anthropogenic 14C Marine Geochemistry in the Vicinity of a Nuclear Fuel Reprocessing Plant

Abstract

The British Nuclear Fuels plc reprocessing plant at Sellafield in Cumbria, Northwest England, discharges between 1 and 3 TBq of 14C per annum as low-level waste via a pipeline into the Eastern Irish Sea. Our results demonstrate 14C activities in excess of the current ambient level (i.e., ca. 260 Bq kg−1 carbon) in a range of both biotic and abiotic samples with evidence that a significant percentage of the discharges are in the form of dissolved inorganic carbon (DIC). There also appears to be a significant seasonal influence on the uptake of the DIC by the phytoplankton, most likely linked to their bloom periods. Results from different aspects of the research are integrated to provide an opportunity to consider the overall distribution and behavior of 14C in the Eastern Irish Sea. We also discuss the results in terms of existing sediment chronologies and sedimentation rates and consider the possible consequences of phytoplankton blooms on the cycling of the other radionuclides.