Radiocarbon in seawater at radioactive waste dumping sites in the Northeast Atlantic and Northwest Pacific

Radiocarbon has been an important constituent of radioactive wastes dumped in the open ocean and marginal seas as well as wastes released from nuclear reprocessing plants. Therefore, in some regions these sources could have a greater impact on ¹⁴C concentration in seawater than global fallout. The high analytical sensitivity of ¹⁴C measurement by accelerator mass spectrometry (AMS) allows even tracer amounts of ¹⁴C to be found in seawater at radioactive waste dumping sites and their comparison with the global distribution of this radionuclide. Data on measurements of ¹⁴C in samples taken at former dumping sites in the northeast Atlantic and northwest Pacific Oceans and in the open ocean are discussed and compared with other anthropogenic radionuclides, namely ³H. Small increases in ¹⁴C concentrations observed in some bottom and surface seawater samples collected at the Northwest Pacific Ocean dumping sites require further ¹⁴C analyses before final conclusions can be made on possible leakages from dumped radioactive wastes.