Publication Abstract

A Sediment History of Sellafield Discharges

P.J. Kershaw, D.S. Woodhead, S.J. Malcolm, D.J. Allington and M.B. Lovett

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 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 1-1.5y. 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.

Reference:

P.J. Kershaw, D.S. Woodhead, S.J. Malcolm, D.J. Allington and M.B. Lovett, 1990. A Sediment History of Sellafield Discharges. Journal of Environmental Radioactivity, 12(3): 201-241.