Distribution and behavior of plutonium isotopes in Western Pacific marginal seas

Cao, Liguo; Zheng, Jian; Zhou, Zhengchao; Bu, Wenting; Wang, Zhongtang; Zheng, Wang; Yamada, Masatoshi

doi:10.1016/j.catena.2020.105023

Cited by 15 publications

(8 citation statements)

References 127 publications

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“…S1 , S2 ). The result of 240 Pu/ 239 Pu higher than 0.18 is similar to that reported from other North Western Pacific seafloors 26 including down core analyses in Sagami Bay, Japan 37 . Measurement of Pu in sediment obtained from Hiroshima-bay 40 located further inside of the Seto Inland Sea (Fig.…”

Section: Discussionsupporting

confidence: 89%

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene

Yokoyama

Tims

Froehlich

et al. 2022

Sci Rep

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Plutonium (Pu) has been used as a mid-twentieth century time-marker in various geological archives as a result of atmospheric nuclear tests mainly conducted in 1950s. Advancement of analytical techniques allows us to measure 239Pu and 240Pu more accurately and can thereby reconstruct the Pacific Pu signal that originated from the former Pacific Proving Grounds (PPG) in the Marshall Islands. Here, we propose a novel method that couples annual banded reef building corals and nearshore anoxic marine sediments to provide a marker to precisely determine the start of the nuclear era which is known as a part of the Anthropocene. We demonstrate the efficacy of the methods using sediment obtained from Beppu Bay, Japan, and a coral from Ishigaki Island, Japan. The sedimentary records show a clear Pu increase from 1950, peaking during the 1960s, and then showing a sharp decline during the 1970s. However, a constantly higher isotope ratio between 239Pu and 240Pu suggest an additional contribution other than global fallout via ocean currents. Furthermore, single elevations in 240Pu/239Pu provide supportive evidence of close-in-fallout similar to previous studies. Coral skeletal radiocarbon displays a clear timing with the signatures supporting the reliability of the Beppu Bay sediments as archives and demonstrates the strength of this method to capture potential Anthropocene signatures.

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Section: Discussionsupporting

confidence: 89%

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene

Yokoyama

Tims

Froehlich

et al. 2022

Sci Rep

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“…It is reported that most of the plutonium in mainland China comes from global fallout; only a few areas have received the impact of regional settlement. , However, radioactive contaminants transmitted to coastal areas were generally received from global fallout and PPG . Cao et al reviewed the sources, spatial and temporal distributions, and geochemical behaviors of plutonium isotopes in the China Seas and proposed that global fallout and PPG are the major sources of Pu in the China Seas. Sources of artificial radionuclides in our study area include global fallout, Pearl River transportation, and PPG.…”

Section: Resultsmentioning

confidence: 99%

²³⁷Np and ²⁴¹Am as Fingerprints in the Major River Basins of Southern China and North South China Sea: A Land–Sea Perspective

Han

Zhu

et al. 2021

ACS Omega

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During the global nuclear weapon tests, large amounts of radioactive elements are released into the environment. Long-period actinide elements such as Np, Pu, and Am exhibit different behaviors in various environments, and their isotope characteristic fingerprints are of great significance for studying the distribution, migration, and prediction of radioactive pollutants. To investigate the distribution of 241 Am and 237 Np in southern China, activities of 241 Am (0.008 ± 0.012−0.932 ± 0.066 Bq/kg) and 237 Np (0.037 ± 0.003−1.458 ± 0.063 mBq/kg), 237 Np/ 239 Pu atom ratios (0.055 ± 0.003−0.864 ± 0.054), and 241 Am/ 239+240 Pu activity ratios (0.033 ± 0.075−15.870 ± 0.477) in 95 surface sediment samples collected from the northern South China Sea and major river basins were analyzed for the first time. Due to the different scavenging mechanisms of Am and Pu, 241 Am is preferentially concentrated by sinking the particulate, while plutonium is scavenged in the coastal area, resulting in a higher 241 Am/ 239+240 Pu activity ratio in estuary and coastal areas. The distribution of 237 Np shows obvious spatial inhomogeneity as the high migration rate. The relevant fingerprint characteristic has changed greatly and needs to be updated urgently. As a result of the convergence of land and sea, 241 Am, 239,240 Pu, and 237 Np are dominated by terrestrial sediments and deposited in the coastal area of southern China, which should be paid more attention to. This work can establish China's current neptunium radioactivity database, and the difference in Np, Pu, and Am scavenging processes may be a powerful tool for evaluating the impact of the Pearl River Estuary salt tide.

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“…Plutonium is an important anthropogenic radionuclide in the environment, and 239 Pu (t½= 24,110 yr) and 240 Pu (t½=6561 yr) are the most important isotopes of plutonium, which have been widely used to estimate the environmental effects of human nuclear activities and to trace environmental processes, such as soil erosion and the behaviors of the suspending particles in the ocean Cao et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…The level, distribution and sources of plutonium isotopes in the sediment samples in the northern SCS (Wu et al, 2014;Dong et al, 2010), seawater samples in the eastern and central SCS (Wu et al, 2018;Yamada et al, 2006) have been investigated. Nevertheless, investigation on the transport pathway and deposition process of plutonium from the overlying water column to surface sediment in different sites is still limited (Cao et al, 2021). Meanwhile, the factors influencing the spatial distribution of plutonium concentration and its isotopic ratio in the different marine environments have not been well investigated, which limited our unstanding on the behavior of the continential runoff sourced and long-distance sea current transported suspending particles.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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Distribution and behavior of plutonium isotopes in Western Pacific marginal seas

Cited by 15 publications

References 127 publications

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene

²³⁷Np and ²⁴¹Am as Fingerprints in the Major River Basins of Southern China and North South China Sea: A Land–Sea Perspective

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

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Distribution and behavior of plutonium isotopes in Western Pacific marginal seas

Cited by 15 publications

References 127 publications

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene

Plutonium isotopes in the North Western Pacific sediments coupled with radiocarbon in corals recording precise timing of the Anthropocene

237Np and 241Am as Fingerprints in the Major River Basins of Southern China and North South China Sea: A Land–Sea Perspective

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

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²³⁷Np and ²⁴¹Am as Fingerprints in the Major River Basins of Southern China and North South China Sea: A Land–Sea Perspective