TY - JOUR
T1 - Controls on anthropogenic radionuclide distribution in the Sellafield-impacted Eastern Irish Sea
AU - Ray, Daisy
AU - Leary, Peter
AU - Livens, Francis
AU - Gray, Neil
AU - Morris, Katherine
AU - Law, Kathleen A.
AU - Fuller, Adam J.
AU - Abrahamsen-Mills, Liam
AU - Howe, John
AU - Tierney, Kieran
AU - Muir, Graham
AU - Law, Gareth T.W.
N1 - Funding Information:
The authors thank the UK EPSRC Nuclear First CDT and the NERC LO-RISE ( NE/L000547/1 ) project (which was part of the NERC Radioactivity and the Environment program, co-funded by the Environment Agency and Radioactive Waste Management Ltd) for funding. Law and Livens acknowledge NERC for additional funding ( NE/M014088/1 ). We also thank Alistair Bewsher and Paul Lythgoe (University of Manchester) for assistance with analysis, and the Master and Crew of the RV Prince Madog for assistance with sampling of the Irish Sea Mudpatch.
Funding Information:
The authors thank the UK EPSRC Nuclear First CDT and the NERC LO-RISE (NE/L000547/1) project (which was part of the NERC Radioactivity and the Environment program, co-funded by the Environment Agency and Radioactive Waste Management Ltd) for funding. Law and Livens acknowledge NERC for additional funding (NE/M014088/1). We also thank Alistair Bewsher and Paul Lythgoe (University of Manchester) for assistance with analysis, and the Master and Crew of the RV Prince Madog for assistance with sampling of the Irish Sea Mudpatch.
Publisher Copyright:
© 2020
PY - 2020/11/15
Y1 - 2020/11/15
N2 - Understanding anthropogenic radionuclide biogeochemistry and mobility in natural systems is key to improving the management of radioactively contaminated environments and radioactive wastes. Here, we describe the contemporary depth distribution and phase partitioning of 137Cs, Pu, and 241Am in two sediment cores taken from the Irish Sea (Site 1: the Irish Sea Mudpatch; Site 2: the Esk Estuary). Both sites are located ~10 km from the Sellafield nuclear site. Low-level aqueous radioactive waste has been discharged from the Sellafield site into the Irish Sea for >50 y. We compare the depth distribution of the radionuclides at each site to trends in sediment and porewater redox chemistry, using trace element abundance, microbial ecology, and sequential extractions, to better understand the relative importance of sediment biogeochemistry vs. physical controls on radionuclide distribution/post-depositional mobility in the sediments. We highlight that the distribution of 137Cs, Pu, and 241Am at both sites is largely controlled by physical mixing of the sediments, physical transport processes, and sediment accumulation. Interestingly, at the Esk Estuary, microbially-mediated redox processes (considered for Pu) do not appear to offer significant controls on Pu distribution, even over decadal timescales. We also highlight that the Irish Sea Mudpatch likely still acts as a source of historical pollution to other areas in the Irish Sea, despite ever decreasing levels of waste output from the Sellafield site.
AB - Understanding anthropogenic radionuclide biogeochemistry and mobility in natural systems is key to improving the management of radioactively contaminated environments and radioactive wastes. Here, we describe the contemporary depth distribution and phase partitioning of 137Cs, Pu, and 241Am in two sediment cores taken from the Irish Sea (Site 1: the Irish Sea Mudpatch; Site 2: the Esk Estuary). Both sites are located ~10 km from the Sellafield nuclear site. Low-level aqueous radioactive waste has been discharged from the Sellafield site into the Irish Sea for >50 y. We compare the depth distribution of the radionuclides at each site to trends in sediment and porewater redox chemistry, using trace element abundance, microbial ecology, and sequential extractions, to better understand the relative importance of sediment biogeochemistry vs. physical controls on radionuclide distribution/post-depositional mobility in the sediments. We highlight that the distribution of 137Cs, Pu, and 241Am at both sites is largely controlled by physical mixing of the sediments, physical transport processes, and sediment accumulation. Interestingly, at the Esk Estuary, microbially-mediated redox processes (considered for Pu) do not appear to offer significant controls on Pu distribution, even over decadal timescales. We also highlight that the Irish Sea Mudpatch likely still acts as a source of historical pollution to other areas in the Irish Sea, despite ever decreasing levels of waste output from the Sellafield site.
KW - Americium
KW - Cesium
KW - Esk Estuary
KW - Irish Sea
KW - Plutonium
KW - Sellafield Ltd.
UR - http://www.scopus.com/inward/record.url?scp=85087738913&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2020.140765
DO - 10.1016/j.scitotenv.2020.140765
M3 - Article
C2 - 32659564
AN - SCOPUS:85087738913
SN - 0048-9697
VL - 743
SP - 1
EP - 14
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 140765
ER -