A sediment history of sellafiel discharges

• Published in: Journal of environmental radioactivity 1990, Vol.12 (3), p.201-241
• Main Authors: Kershaw, P.J., Woodhead, D.S., Malcolm, S.J., Allington, D.J., Lovett, M.B.
• Format: Article
• Language: English
• ISSN: 0265-931X; 1879-1700
• DOI: 10.1016/0265-931X(90)90024-P

A suite of artificial radionuclides, discharged from the BNFL Sellafield works into the Irish Sea, has been measured in sediment cores taken from a nearby disused and undisturbed dock basin (Senhouse Dock, Maryport). This has provided a comprehensive record of Sellafield discharges from the early 1960s, including radionuclides for which discharge data are in incomplete A chronology was established by comparing a variety of radionuclide concentrations and isotope ratios in the core with the available information on decay-corrected discharges. This allowed an estimate to be made of the quantity of 238Pu discharged in the period 1959–1977 (94 ± 8 TBq) for which no discharge data exist. The transit time from discharge to incorporation in the surface sediment was in the order of 1–1·.5 y. Attempts to verify the sediment chronology with conventional 210Pb excess dating met with difficulties because of uncertainties in the flux of 210Pb, linked to a local, anthropogenic source of 210Pb/ 226Ra.