scholarly journals Impact of typhoons on particulate and dissolved <sup>137</sup>Cs activities in seawater off the Fukushima Prefecture: results from the SOSO 5 Rivers cruise (October 2014)

2021 ◽  
Author(s):  
Michio Aoyama ◽  
Sabine Charmasson ◽  
Yasunori Hamajima ◽  
Celine Duffa
Keyword(s):  
Activity Concentration ◽  
Activity Ratio ◽  
Coastal Region ◽  
137Cs Activity ◽  
137Cs Activity Concentration ◽  
Fukushima Prefecture ◽  
The Core ◽  
Organic Particles ◽  
Dissolved Form ◽  
134Cs Activity

Abstract. Cruise SoSo 5 Rivers took place during October 2014 off the coast of Fukushima Prefecture shortly after the passage of two typhoons. Detection of dissolved 134Cs and 137Cs in all samples reflected contamination caused by accidental releases of radiocaesium from the Fukushima Dai-ichi Nuclear power plant (FNPP1) accident. The dissolved activities were generally higher at coastal sites and decreased with distance from shore, and they were higher in the surface than in the bottom water. The tendency of 137Cs activities to decrease with distance from the coast reflected mixing of coastal water and open-ocean water of which 137Cs activity concentration was ~1.5 Bq m−3. At stations very close to the coast, we observed high particulate 137Cs activity concentration that exceeded dissolved 137Cs activity concentration. 137Cs activities were generally 1–2 orders of magnitudes lower in organic particles than in dissolved form, and the ratios of 137Cs activity concentration in organic particles to 137Cs activity concentration in dissolved form ranged from 0.01 ± 0.00 to 0.12 ± 0.01. The ratio of 137Cs to 134Cs activity concentrations in organic particles did not change with distance from shore or with 137Cs activity concentration and generally remained around 1, even in samples collected far from the coast. This pattern indicated that the organic particles had come from rivers or a source very close to the coast. The 137Cs / 134Cs activity ratio in dissolved form north of FNPP1 region was estimated to be 1.074 ± 0.015, a ratio that is in good agreement with the 137Cs / 134Cs activity ratio in the core of Unit 1 of the FNPP1 while the 137Cs / 134Cs activity ratio at Tomioka port which located south of FNPP1 was 0.998 ± 0.017. Therefore we can conclude the source of radiocaesium in seawater in the coastal region north of FNPP1 was deposited radiocaesium released from the core of Unit 1 of FNPP1, while the source of radiocaesium observed in the coastal region south of FNPP1 was a mixture of deposited radiocaesium released from the core of Unit 2 and the core of Unit 1 of FNPP1. During September–October of each year, the typhoon season in Japan, the 137Cs activity concentration generally increased at Ukedo port, Tomioka port, FNPP1, and Iwasawa beach, and showed a good relationship with the 7-day modified antecedent precipitation index (API) while there is less correlation between the modified API and 137Cs activity concentration near the outlet of canal from unit 5 and 6 of FNPP1 to the sea.

Evolution of 137Cs Activity Concentration in the Aegean Sea

2021 ◽  
Author(s):  
Christos Tsabaris ◽  
Georgios Eleftheriou ◽  
Filothei K. Pappa ◽  
Heleni Kaberi ◽  
Stylianos Iliakis ◽  
...  
Keyword(s):  
Activity Concentration ◽  
Aegean Sea ◽  
137Cs Activity ◽  
137Cs Activity Concentration

Radionuclides in deposition in the Ignalina NPP region in 2005

Open Physics ◽  
2006 ◽  
Vol 4 (4) ◽  
Author(s):  
Rimvydas Jasiulionis ◽  
Andrej Rožkov
Keyword(s):  
Nuclear Power ◽  
Particle Deposition ◽  
Activity Concentration ◽  
Ground Level ◽  
137Cs Activity ◽  
Hysplit Model ◽  
Solubility In Water ◽  
137Cs Activity Concentration ◽  
Chernobyl Npp ◽  
Ground Level Air

AbstractResults of radionuclide activity concentration measurements in deposition and ground-level air conducted at the station of the Institute of Physics situated 3.5 km from the Ignalina Nuclear Power Plant (Ignalina NPP) in 2005 are analyzed. Atmospheric depositional fluxes of 7Be, 60Co and 137Cs are estimated. Radionuclide particle deposition rates are calculated. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model of the global dispersion and deposition is used to explain variations in the 137Cs activity concentration in the ground-level air in the Ignalina NPP region in 2005. An increase in the 137Cs activity concentration of up to 17.4 µBq m−3 on 30 October-5 November is studied. Modelling results show that the Chernobyl NPP Unit 4 Sarcophagus and the radiocaesium resuspension from the Chernobyl NPP accident polluted regions are sources of 137Cs to the environment of the Ignalina NPP. Results on solubility in water of aerosols — carriers of 137Cs — are discussed.

scholarly journals Estimation of the Contribution of Dust Storm on April 16, 2020 to Radioactive Contamination of the Atmosphere During Forest Fires in the Exclusion Zone

2021 ◽  
Vol 20 ◽  
pp. 81-95
Author(s):  
M. M. Таlerko ◽  
◽  
Т. D. Lev ◽  
V. O. Кashpur ◽  
◽  
...  
Keyword(s):  
Forest Fires ◽  
Dust Storm ◽  
Nuclear Power ◽  
Activity Concentration ◽  
Total Activity ◽  
137Cs Activity ◽  
Wildland Fires ◽  
Exclusion Zone ◽  
137Cs Activity Concentration ◽  
Burned Areas

On April 16, 2020, a strong dust storm was observed in the northern regions of Ukraine, which coincided with the period of intense wildland fires in the Chornobyl exclusion zone. The activity of 137Cs in aerosol particles released into the atmosphere as a result of resuspension from burned areas in the meadow biocenoses in the exclusion zone is evaluated in the article. Resuspension of radioactively contaminated particles from burned areas formed after fires in meadow biocenoses of the exclusion zone can be a powerful source of air contamination in the zone itself, as well as increase of the radionuclides transport outside it. The total 137Cs activity that entered the atmosphere during the dust storm was estimated to be about 162 GBq, i. e. up to 20% of the total activity emitted in the air during the entire period of forest fires on April 3–20, 2020. The 137Cs emission from burned areas during the dust storm on April 16 and 17 amounted to 0.24% of the total stock of 137Cs activity in this territory. According to the results of modeling, the relative contribution of wildland fires and resuspension due to the dust storm on April 16 and 17 significantly depends on the distance to the emission sources. It was found that the resuspension of radioactive particles from burned areas during the dust storm determined 80–95% of the 137Cs activity concentration in the surface air near Chornobyl nuclear power plant and in Chornobyl city and the rest was due to the continuing forest fires in neighboring territories. The maximum 3-hour averaged value of the 137Cs activity concentration in the air due to resuspension from the burned areas was obtained for the location of the monitoring post VRP-750 of SSE “Ecocenter” to be about 28 mBq/m3 for the period 9–12 hours on April 16. In Kyiv, the 3-hour averaged 137Cs activity concentration due to the dust storm in the Exclusion Zone was calculated as 44 μBq/m3 in the period from 9 to 12 hours on April 17, 2020. This value was only about 4% of the total 137Cs activity in the air in this period.

scholarly journals Tritium activity concentration and behaviour in coastal regions of Fukushima in 2014

2021 ◽  
Author(s):  
Michio Aoyama ◽  
Sabine Charmasson ◽  
Yasunori Hamajima ◽  
Celine Duffa ◽  
Daisuke Tsumune ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Activity Concentration ◽  
Coastal Region ◽  
Open Water ◽  
Major Axis ◽  
137Cs Activity ◽  
Freshwater Flux ◽  
Monthly Precipitation ◽  
Activity Concentrations ◽  
North And South

Abstract. We observed 3H activity concentrations and the 137Cs activity concentrations during the SoSo 5 rivers cruise in 2014 and at the Tomioka port in 2014–2018. The 3H activity concentrations at coastal stations located close to the Fukushima coast ranged from 90 Bq m−3 to 175 Bq m−3, and decreased between 67 Bq m−3 to 83 Bq m−3 at the stations located 12–16 km from the coast. The 3H activity concentration at the estuaries and ports, except at 56 north canal of the FNPP1 site, are around 200–500 Bq m−3 and slightly lower than the 3H activity concentration of 500–600 Bq m−3 observed in the rivers. These gradients of the 3H activity concentrations in the coastal region might indicate the large effect of 3H flux through the rivers. On the other hand, the 3H activity concentration at 56N of the FNPP1 site was significantly high compared to the 3H activity concentration in surrounding waters both north and south of the FNPP1 site and in river waters. It should also be noted that the 3H activity concentrations were similar at the stations located both north and south of the FNPP1 site, while the 137Cs activity concentrations were lower at the stations north of the FNPP1 site and higher at the stations south of the FNPP1 site. This indicated that the major sources of 137Cs could be the FNPP1 site as the point source while the source of 3H should be more diffuse and linked to riverine inputs located north and south of the FNPP1 site. The 3H / 137Cs activity ratios in coastal waters were 1.2–2.2 as obtained via the slopes by standardised major axis regressions between the 3H activity concentration and the 137Cs activity concentration of SoSo samples and Tomioka Port observed in 2014–2018, which is significantly high compared to that of the released radionuclides derived from the FNPP1 site, which was 0.01 in 2011 just after the accident. The open-water 3H activity concentration contribution to coastal waters was estimated to be 67 ± 20 Bq m−3 and 66 ± 17 Bq m−3 as the intercepts also by standardised major axis regressions. These estimates are consistent with 50 Bq m−3 obtained at the Kuroshio region as the background levels of 3H activity concentration in open water. The 3H and 137Cs fluxes to the coastal region of Fukushima based on the open-water movement, freshwater flux from the rivers based on their respective catchment, and mean monthly precipitation were estimated. The largest 3H flux is the open-water inflow from the north of the FNPP1 site and it reaches 52 GBq day−1, while the rivers north of the FNPP1 site showed 3–5 GBq day−1 fluxes. We obtained a 3H flux as 1.9–4.5 GBq day−1 of 3H using the 3H activity concentration in the port, which is comparable with the fluxes obtained from the rivers located north of the FNPP1 site. While using 3H activity concentration at the 56 north canal of FNPP1, we obtained 28–86 GBq day−1 fluxes, which is one order of magnitude larger than those estimated using 3H activity concentration in the FNPP1 port. One of the reasons could be the very high variability of the 3H levels at 56 north canal and in the port of FNPP1, explaining variable 3H/137Cs activity ratio observed at 56 north canal and in the port of FNPP1. The 3H activity concentration of TFWT in the fish filets collected close to the FNPP1 site ranged from 97 ± 11 Bq m−3 to 144 ± 11 Bq m−3, which were similar to the 3H activity concentrations in the surrounding seawater, in agreement with the knowledge that the bioconcentration factor of 3H is approximately 1. In contrast, higher values were found in TOBT, which can be linked to life-history traits.

Long range transport of radiocaesium derived from global fallout and the Fukushima accident in the ocean interior of the Pacific Ocean since 1960s through 2017

2020 ◽  
Author(s):  
Michio Aoyama ◽  
Yasunori Hamajima ◽  
Yayoi Inomata ◽  
Hideki Kaeriyama ◽  
Yuichiro Kumamoto ◽  
...  
Keyword(s):  
Activity Concentration ◽  
Global Fallout ◽  
Basic Feature ◽  
137Cs Activity ◽  
Fukushima Accident ◽  
137Cs Activity Concentration ◽  
Artificial Radionuclides ◽  
Shape Distribution ◽  
Mode Waters ◽  
Range Transport

&lt;p&gt;The world's oceans act as a sink for artificial radionuclides as well as for other anthropogenic pollutants released into the environment. Owing to physical and biogeochemical processes in the ocean, artificial radionuclides in the ocean are redistributed from their initial entry points which depend on the various sources. Long range transport of radiocaesium in the ocean interior were investigated and presented. Radiocaesium were derived from global fallout which occurred mainly late 1950s and early 1960s and the Fukushima accident occurred in 2011. In the ocean interior, main factor is subduction of mode water formation from surface to two mode waters, STMW and CMW. Radiocaesium then stayed long in both STMW and CMW, but relatively first recirculation and southward movement were observed in STMW for decadal time scale.&lt;/p&gt;&lt;p&gt;We establish database for artificial Radionuclides in the marine environment as HAM global 2018, doi: 10.34355/CRiED.U.Tsukuba.00001, and we reconstruct 137Cs activity concentration sections for 1965-1968 and 1970-1973 to understand initial conditions of 137Cs activity concentration in ocean interior just after large atmospheric fallout in early 1960s and 5 years after injection. We also carried out observations at stations between 49 deg. N and 60 deg. S along 165 deg.&amp;#160; E in 2002, 2012 and 2015. After that, we also observed vertical profiles in the western North Pacific Ocean.&amp;#12288;&lt;/p&gt;&lt;p&gt;Basic feature of radiocaesium distribution along 165 deg. E section in 1963-1965 was dome shape distribution of which deepest places were around 30-40 deg. N and of which maximum depth were around 600- 800 meter depths. The penetration of 137Cs is found less than 800 m depth, associated with the bowl shape of isopycnals in the midlatitude region. In general, the 137Cs activity concentrations in the subsurface and intermediate water of the mid latitude region of the western North Pacific were higher than those in surface waters of the subtropical and equatorial Pacific. In 2002, we observed two 137Cs activity concentration maxima at 250 m and at 400 to 500 m depth at around 20 deg. N. The 137Cs activity concentration at the core at 400 to 500 m depth in 2002 was around 2 &amp;#8211; 3 Bq m-3 and the start of moving in 1963-1965 was 16 Bq m-3 which indicates only one thirds of dilution occurred during about 40 years travel in the ocean interior as CMW. In 2012, we also observed two 134Cs activity concentration maxima at 150 m, 30 deg. N and at 300 m depth at 40N, while we observed a Fukushima derived at 300 m, 30 deg. N with southward movements. Basic feature of 137Cs distribution derived from atmospheric weapons test along 165 deg. E section in 2012 still keep dome shape distribution of which deepest places were around 30-35 deg. N and of which maximum depth were around 400 meters depths, while deepest places were around 20-30 deg. N in 2015. These findings strongly suggest that radiocaesium has been transporting in the ocean interior by subduction of mode waters from subarctic region to subtropical region and tropical region.&lt;/p&gt;

Time-dependence of 137Cs activity concentration in wild game meat in Knyszyn Primeval Forest (Poland)

2015 ◽  
Vol 141 ◽  
pp. 76-81 ◽  
Author(s):  
Jacek Kapała ◽  
Krystian Mnich ◽  
Stanisław Mnich ◽  
Maria Karpińska ◽  
Agnieszka Bielawska
Keyword(s):  
Time Dependence ◽  
Activity Concentration ◽  
137Cs Activity ◽  
137Cs Activity Concentration ◽  
Game Meat ◽  
Primeval Forest ◽  
Wild Game
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