Distribution and inventories of 90Sr, 137Cs, 241Am and Pu isotopes in sediments of the Northwest Pacific Ocean

Lee, Sang‐Han; Povinec, P.; Wyse, E.; Pham, Mai Khanh; Hong, Gi-Hoon; Chung, Chang-Soo; Kim, Suk-Hyun; Lee, Hee Jun

doi:10.1016/j.margeo.2005.02.013

Cited by 95 publications

(50 citation statements)

References 39 publications

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“…A significant part of caesium and other radionuclides will bind to suspended particles and cause sedimentary contamination by deposition on the seafloor, as observed previously for atmospheric fallout from nuclear tests (Lee et al, 2005;Moon et al, 2003). Consequences will be significant for months and years in the vicinity of the plant.…”

Section: Introductionmentioning

confidence: 78%

Estimation of marine source-term following Fukushima Dai-ichi accident

Bois

Laguionie

Boust

et al. 2012

Journal of Environmental Radioactivity

215

113

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Contamination of the marine environment following the accident in the Fukushima Dai-ichi nuclear power plant represented the most important artificial radioactive release flux into the sea ever known. The radioactive marine pollution came from atmospheric fallout onto the ocean, direct release of contaminated water from the plant and transport of radioactive pollution from leaching through contaminated soil. In the immediate vicinity of the plant (less than 500 m), the seawater concentrations reached 68,000 Bq.L(-1) for (134)Cs and (137)Cs, and exceeded 100,000 Bq.L(-1) for (131)I in early April. Due to the accidental context of the releases, it is difficult to estimate the total amount of radionuclides introduced into seawater from data obtained in the plant. An evaluation is proposed here, based on measurements performed in seawater for monitoring purposes. Quantities of (137)Cs in seawater in a 50-km area around the plant were calculated from interpolation of seawater measurements. The environmental halftime of seawater in this area is deduced from the time-evolution of these quantities. This halftime appeared constant at about 7 days for (137)Cs. These data allowed estimation of the amount of principal marine inputs and their evolution in time: a total of 27 PBq (12 PBq-41 PBq) of (137)Cs was estimated up to July 18. Even though this main release may be followed by residual inputs from the plant, river runoff and leakage from deposited sediments, it represents the principal source-term that must be accounted for future studies of the consequences of the accident on marine systems. The (137)Cs from Fukushima will remain detectable for several years throughout the North Pacific, and (137)Cs/(134)Cs ratio will be a tracer for future studies.

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Section: Introductionmentioning

confidence: 78%

Estimation of marine source-term following Fukushima Dai-ichi accident

Bois

Laguionie

Boust

et al. 2012

Journal of Environmental Radioactivity

215

113

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“…were not found in the manganese crust below a depth of 0.5 cm in contrast to the deep-sea sediment in which the 239, 240 Pu atoms were detected even at a depth of around 10 cm (Lee et al, 2005;Zheng and Yamada, 2005) from the surface. Hence, the manganese crust may be a better candidate than the deep-sea sediment in searching for the extinct nuclide 244 Pu, which has its origins in outer space.…”

Section: Estimation Of Deposition Rate Of Extraterrestrial Materialsmentioning

confidence: 62%

“…The 3 He depth profile demonstrates that the degassing of 3 He is insignificant, i.e., an element incorporated into a particle hardly migrates out of the manganese encrustation. Additionally, the anthropogenic 239, 240 Pu contents of the surface of the manganese crust (Lee et al, 2005) were found to be about three orders less than those of the deep-sea sediment. 239, 240 Pu atoms…”

Section: Estimation Of Deposition Rate Of Extraterrestrial Materialsmentioning

confidence: 90%

Incorporation rate measurements of 10Be, 230Th, 231Pa, and 239,240Pu radionuclides in manganese crust in the Pacific Ocean: A search for extraterrestrial material

et al. 2007

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In order to estimate the deposition rate of extraterrestrial material onto a manganese crust in a project to search for supernova debris, we analyzed the contents of 10 Be, 230 Th, 231 Pa, and 239, 240 Pu in a sample of manganese crust collected from the North Pacific Ocean. On the basis of the depth profile of 10 Be, the growth rate of the manganese crust was determined to be 2.3 mm Myr −1 . The uptake rates of 10 Be, 230 Th, and 231 Pa onto the manganese crust were estimated to be 0.22−0.44%, 0.11−0.73%, and 1.4−4.5%, respectively, as compared to the deposition rates onto the deep-sea sediments near the sampling station and that for 239, 240 Pu was 0.14% as compared to the total inventory of seawater and sediment column. Assuming the sinking particles to be 0.11−4.5% of the uptake rates, the deposition rate of extraterrestrial material onto the manganese crust was estimated to be 2−800 μg cm −2 Myr −1 according to the uptake of 10 Be onto the manganese crust. Further, our estimate is similar to the value of 9−90 μg cm −2 Myr −1 obtained using the integrated global production rate of 10 Be and the deposition rate of 10 Be onto the manganese crust.

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“…The Japanese government investigated Pu isotopes in the surface sediments off Japan and reported 241 Pu activities less than 3.3 mBq g −1 [ 23 ]. However, as a result of the infl uence of the PPG close-in fallout, high 241 Pu activities (up to 19-33 mBq g −1 ) were observed in the sediment near Bikini Atoll [ 24 ]. 240 Pu/ 239 Pu atom ratios in the Japanese near-coastal surface sediments ranged from 0.17 to 0.27 ( Fig.…”

Section: Distribution Of Pu Isotopes In the Marinementioning

confidence: 99%

Distribution of Plutonium Isotopes in Marine Sediments off Japan Before and After the Fukushima Dai-ichi Nuclear Power Plant Accident: A Review

Zheng²,

Guo

et al. 2013

Radiation Monitoring and Dose Estimation of the Fukushima Nuclear Accident

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A large amount of radionuclides was released into the atmosphere and directly discharged into the ocean as a consequence of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. The possible actinides, especially plutonium contamination in the ocean from the nuclear accident, attracted general public and scientifi c concern. In this review, we summarize studies of the distribution of Pu isotopes in the marine sediments off Japan before and after the FDNPP accident to assess possible Pu contamination from the nuclear accident. Our results suggested that there was no detectable additional Pu injection from the FDNPP accident in the marine environment 30 km off the FDNPP 1 year after the accident. The detectable Pu isotopes originated from global fallout and the Pacifi c Proving Ground close-in fallout. Keywords FDNPP • Marine sediments • Plutonium isotopes IntroductionOn March 11, 2011, the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) was hit and damaged by a magnitude 9.0 earthquake in the Northwest Pacifi c about 130 km off the northeast coast of Japan and the following gigantic tsunami. As a result, large amounts of radionuclides were released into the atmosphere and directly discharged into the sea. More than 70 % of the released radionuclides were deposited over the North Pacifi c Ocean [ 1 ]. Studies concerning the fi ssion products, such as 131 I and radiocesium, were carried out intensively after the nuclear accident. However, information about actinides, especially the plutonium (Pu) isotopes, is limited.Pu isotopes are of public and scientifi c interest because they are characterized by radiotoxicity and strong chemical toxicity. They contribute much to the longterm dose for humans because of their relatively long half-lives ( 238 Pu, 87.7 years; 239 Pu, 24,110 years; 240 Pu, 6,561 years; 241 Pu, 14.4 years) . Investigating the characterization of Pu isotopes in marine sediments is important for purposes of environmental monitoring and radiotoxicity assessment. Moreover, Pu isotopes are considered as new geochemical tracers for the study of oceanic processes, such as sedimentation and particle scavenging, and the isotopic composition of Pu ( 240 Pu/ 239 Pu) has been used as an important fi ngerprint for environmental radioactive source identifi cation [ 2 -5 ].Abnormal atom ratios of 240 Pu/ 239 Pu and 241 Pu/ 239 Pu, and activity ratios of 241 Pu/ 239+240 Pu and 238 Pu/ 239+240 Pu, have been reported in surface soil and litter samples in the 20-to 30-km zone around the FDNPP [ 6 , 7 ], suggesting the atmospheric release of Pu isotopes from the nuclear accident. For the marine environment, in previous studies [ 8 , 9 ] we investigated the distribution of Pu isotopes in marine sediments collected in the Pacifi c Ocean, 30 km off the FDNPP site, from July 2011 to July 2012 after the nuclear accident. Sakaguchi et al. [ 10 ] determined Pu concentration in seawaters in the Pacifi c, 50 km off the FDNPP, and they observed no significant amount of extra components from the nuclear accident...

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Distribution and inventories of 90Sr, 137Cs, 241Am and Pu isotopes in sediments of the Northwest Pacific Ocean

Cited by 95 publications

References 39 publications

Estimation of marine source-term following Fukushima Dai-ichi accident

Estimation of marine source-term following Fukushima Dai-ichi accident

Incorporation rate measurements of 10Be, 230Th, 231Pa, and 239,240Pu radionuclides in manganese crust in the Pacific Ocean: A search for extraterrestrial material

Distribution of Plutonium Isotopes in Marine Sediments off Japan Before and After the Fukushima Dai-ichi Nuclear Power Plant Accident: A Review

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