Transuranic nuclides Pu, Am and Cm isotopes, and 90Sr in seafloor sediments off the Fukushima Daiichi Nuclear Power Plant during the period from 2012 to 2019

Plutonium Isotopes in the Northwestern South China Sea: Level, Distribution, Source and Deposition

“…5), reflecting the different transport and deposition of plutonium in the corresponding sedimentary environments in the SCS after the entrance of the branch of Kuroshio Current carrying PPG derived plutonium. This is in agreement with the reported PPG contributions in the sediment in the northern SCS shelf (~58%), the central SCS (~57%) and the Okinawa Trough (~56%) (Wu et al, 2014;Dong et al, 2010;Wang and Yamada, 2005), and slightly higher than those in the East China Sea Shelf (~41%), the Japan Sea (~43%) (Wang et al, 2017;Yamada et al, 2021).…”

“…The elevated 240 Pu/ 239 Pu atomic ratios observed in the SCS surface sediment in this work compared to the global fallout signal should be mainly attributed to the continuous input of the PPG derived plutonium. Many investigations also observed higher 240 Pu/ 239 Pu atomic ratios in the regions affected by Kuroshio Current (Wang and Yamada, 2005;Dong et al, 2010;Wu et al, 2014;Wang et al, 2017;Yamada et al, 2021). It was noticed that the highest 240 Pu/ 239 Pu atomic ratio (0.31 ± 0.10) was measured in the sediment at st. 7, which is located in the most east site to the Luzon Strait, reflecting a significant contribution of PPG derived Pu.…”

“…2) (Zhang et al, 2018;Xu et al, 2018;Wang et al, 2017;Wang and Yamada, 2005;Wu et al, 2014;Dong et al, 2010;Moon et al, 2003;Yamada et al, 2021), which are two orders of magnitude lower than that near the Sellafield reprocessing plants (RP) and Pacific Proving Grounds (PPG) (Lindahl et al, 2011;Lachner et al, 2010).…”

“…It has been reported that some amount of plutonium has been released into the environment from the nuclear accidents, and higher 240 Pu/ 239 Pu atomic ratios of 0.386 -0.412 in the Chernobyl derived materials (Boulyga et al, 1997) and 0.323-0.330 in the Fukushima derived materials (Zheng et al, 2012) compared to the global fallout were measured. However, the region affected by the Fukushima derived plutonium was mainly within 30 km off the Fukushima Daiichi Nuclear Power Plant (FDNPP) (Zheng et al, 2012) and no significant increase of 239, 240 Pu concentration in the environment near the FDNPP in 2012 -2019 was observed (Yamada et al, 2021). Plutonium as particle-associated radionuclide released from the Chernobyl accident was mainly deposited in surrounding areas of the Chernobyl, and no Chernobyl derived plutonium in soils from China and the marginal of Pacific Ocean has been reported (Wu et al, 2010;Wu et al, 2014).…”

“…A large number of investigations on plutonium isotopes in soil, sediments, seawater and coral in the Northern Hemisphere (Wang and Yamada, 2005;Zheng et al, 2012;Zhang et al, 2018;Xu et al, 2018;Wang et al, 2017;Liu et al, 2011Liu et al, , 2020Wu et al, 2014;Dong et al, 2010;Roviello et al, 2020;Guan et al, 2021;Yamada et al, 2021) and Southern Hemisphere (Srncik et al, 2014;Tims et al, 2016) have been J o u r n a l P r e -p r o o f 3 reported. Among of them, the marginal seas of the western Pacific Ocean, e.g.…”