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Journal of Environmental Radioactivity 102 (2011) 1062e1064

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Journal of Environmental Radioactivity

journal homepage: www.elsevier .com/locate / jenvrad

Short communication

Evidence of the radioactive fallout in the center of Asia (Russia)following the Fukushima Nuclear Accident

A. Bolsunovsky*, D. DementyevRadioecology Laboratory, Institute of Biophysics, Siberian Branch of Russian Academy of Sciences, Akademgorodok, 50-50, 660036 Krasnoyarsk, Russian Federation

a r t i c l e i n f o

Article history:Received 11 May 2011Received in revised form15 June 2011Accepted 18 June 2011Available online 13 July 2011

Keywords:Radioactive falloutEnvironmental samplesFukushima nuclear accidentFission product radionuclidesRussia

* Corresponding author. Tel.:þ7 391 2494572; fax: þE-mail address: radecol@ibp.ru (A. Bolsunovsky).URL: http://www.ibp.ru/

0265-931X/$ e see front matter � 2011 Elsevier Ltd.doi:10.1016/j.jenvrad.2011.06.007

a b s t r a c t

It was recently reported that radioactive fallout due to the Fukushima Nuclear Accident was detected inenvironmental samples collected in the USA and Greece, which are very far away from Japan. In AprileMay 2011, fallout radionuclides (134Cs, 137Cs, 131I) released in the Fukushima Nuclear Accident weredetected in environmental samples at the city of Krasnoyarsk (Russia), situated in the center of Asia.Similar maximum levels of 131I and 137Cs/134Cs and 131I/137Cs ratios in water samples collected in Russiaand Greece suggest the high-velocity movement of the radioactive contamination from the FukushimaNuclear Accident and the global effects of this accident, similar to those caused by the Chernobylaccident.

� 2011 Elsevier Ltd. All rights reserved.

An earthquake followed by a tsunami that occurred at theFukushima Daiichi complex on March 11, 2011 caused release ofradionuclides into the environment (Brumfiel and Cyranoski, 2011;Butler, 2011; Reardon, 2011). On April 12, 2011, the Nuclear andIndustrial Safety Agency of Japan (NISA) submitted a provisionalInternational Nuclear and Radiological Event Scale Level 7 rating forthe Fukushima accident (IAEA, 2011). The only other accident tohave an INES Level 7 rating was the Chernobyl accident in 1986.However, NISA estimates that the Fukushima nuclear releases tothe atmosphere were approximately 10% of the Chernobyl accident(IAEA, 2011). The Fukushima Nuclear Accident has also causedglobal effects, as suggested by the first measurements of 133Xe thatwere conducted at the Pacific Northwest National Laboratory (USA)(46�1604700N, 119�1605300W) located more than 7000 km fromFukushima (37�2501700N, 141�105700E) (Bowyer et al., 2011). Firstdetections of 133Xe were made starting early March 16, only fourdays following the accident, and then high concentrations of 133Xewere determined daily. On March 22, 2011, the U.S. EnvironmentalProtection Agency (EPA, 2011) reported that analysis of samplescaptured by RadNet air monitor filters in the states of California andWashington on March 18 detected fission product radionuclides(137Cs, 132Te, 132I, 131I). Subsequently, the cloud containing

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radioactivity moved over the USA and the Atlantic Ocean and thendiffused over the European continent. The first data on radioactivefallout in Europe (Greece) were reported by scientists of AristotleUniversity of Thessaloniki (40�380N, 22�580E) (Manolopoulou et al.,2011). From March 24 through April 9, radionuclides (134Cs, 137Cs,131I) released in the nuclear accident at Fukushima were recordedin air samples collected at Thessaloniki. The only isotope detectedin rainwater and in the sheep milk collected on March 29e30, 2011in Greece was 131I (Manolopoulou et al., 2011).

The cloud containing radioactivity was expected to movetoward Asia, but until now, no data have been published onradioactive fallouts in Asian countries. From April 3 through May 32011, environmental samples were collected in the city of Kras-noyarsk (Russia) (Krasnoyarsk-1, 55�590210 0N, 92�450360 0E) and inits environs (Krasnoyarsk-2, 56�050500 0N, 92�3500300E). Analysis wasperformed on samples of rainwater, melted snow, pine (Pinus syl-vestris L.) needles, and the air filter membrane. Samples of freshsnow collected from an area of 2e9 m2 were melted at roomtemperature. Rainwater samples were collected in plasticcontainers. All water samples were filtered. One liter of water wastaken immediately after filtering to perform preliminary rapidanalysis for radionuclides using g-ray-spectrometry. Then, thewater was concentrated by evaporation on an electric stove toa volume of 1 L, in order to attain a more accurate determination ofradionuclides. To avoid any loss by evaporation of iodine isotopesduring heating, a method approved by the Russian Ministry ofHealth was used: 10 drops of 1% phenolphthalein solution were

Table 1Fission product radionuclides in environmental samples collected at Krasnoyarsk (Russia) between April 4 and May 3, 2011.

Sampled material, sampling date and area 131I 134Cs 137Cs 137Cs/134Cs 131I/137Cs

Melted snow April 04.2011, Krasnoyarsk�1 0.62 � 0.05 Bq/L 0.095 � 0.02 Bq/L 0.075 � 0.03 Bq/L 0.79 8.3Melted snow April 04.2011, Krasnoyarske2 0.39 � 0.02 Bq/L 0.031 � 0.002 Bq/L 0.037 � 0.004 Bq/L 1.19 10.5Melted snow April 06.2011, Krasnoyarsk�1 0.405 � 0.015 Bq/L 0.026 � 0.002 Bq/L 0.024 � 0.004 Bq/L 0.92 16.9Melted snow April 06.2011, Krasnoyarske2 0.53 � 0.04 Bq/L 0.048 � 0.004 Bq/L 0.055 � 0.007 Bq/L 1.15 9.6Rainwater April 28.2011, Krasnoyarsk-1 0.052 � 0.004 Bq/L 0.005 � 0.001 Bq/L 0.007 � 0.003 Bq/L 1.40 7.4Rainwater April 27.2011, Krasnoyarsk-2 0.058 � 0.019 Bq/L <MDA <MDA e e

Rainwater May 03.2011, Krasnoyarsk-2 0.031 � 0.007 Bq/L 0.006 � 0.002 Bq/L <MDA e e

Pine needles April 10.2011, Krasnoyarsk-1 3.28 � 0.31 Bq/kg DW 0.74 � 0.11 Bq/kg DW 1.03 � 0.20 Bq/kg DW 1.39 3.20.83 � 0.20 Bq/kg DWa 1.12a 4.0a

Air filter membrane March 01eApril 03. 2011,Krasnoyarsk-1

0.63 � 0.05 Bq 0.11 � 0.02 Bq 0.20 � 0.04 Bq 1.82 3.2

Rainwater in Northern Greeceb March 29.2011 Up to 0.7 Bq/L <MDA <MDASamples of air in Northern Greeceb

April 1e4.2011/April 4e5.2011340� 36=497� 53 mBq m�3 15� 3=126� 11 mBq m�3 23� 7=145� 18 mBq m�3 1:5=1:2 14:8=3:4

a 137Cs activity concentrations and radionuclide ratios in pine needles are the data obtained after deduction of 137Cs background activity.b The data reported by Manolopoulou et al. (2011) are given for comparison purposes.

A. Bolsunovsky, D. Dementyev / Journal of Environmental Radioactivity 102 (2011) 1062e1064 1063

added to the filtered water, and then we gradually added K2CO3till the solution turned bright crimson and did not change colorwhen mixed. The concentrated water samples were analyzed byg-ray-spectrometry. Needles collected from individually growingpine trees (P. sylvestris L.) were dried. For rapid detection ofradionuclides in the needles, an aliquot of needles was placed ina 1-L Marinelli beaker and analyzed by g-ray-spectrometry. Toattain a more accurate determination of radionuclides, the nee-dles were concentrated by ashing. To avoid any loss by evapora-tion of iodine isotopes during ashing, a method approved by theRussian Ministry of Health was used. K2CO3 amounting to 20% ofthe sample mass was added to dry needles. The mixture waswetted with water, mixed thoroughly, and dried. Then the samplewas ashed in a muffle furnace, at a temperature graduallyincreased (by 50 �C every 30 min) to 450 �C. The ashed samplewas analyzed by g-ray-spectrometry. The membrane of the airfilter that had worked to purify the air for at least a month byApril 3, 2011, the sampling date, was first dried in a drying ovenand then prepared for g-ray-spectrometry. The activity concen-trations of the radionuclides (131I, 134Cs, 137Cs, etc.) in the sampleswere measured on a Canberra g-spectrometer (USA) coupled toa GX2320 23% hyper-pure germanium detector in a 1-L Marinellibeaker.

From April 4 through 6, fresh snow samples were collected inthe city of Krasnoyarsk (Russia) (Krasnoyarsk-1) and in its environs(Krasnoyarsk-2); the snowwas melted, and the water was found tocontain radionuclides released in the Fukushima Nuclear Accident(134Cs, 137Cs, 131I) (Table 1). The highest 131I activity that werecorded was 0.62 Bq/L and the highest 137Cs and 134Cs activitieswere 0.075 and 0.095 Bq/L, respectively. The highest 131I activityconcentration in the melted snow sample collected on April 4, 2011was similar to the 131I concentration in the rainwater collected inGreece on March 29, 2011: 0.7 Bq/L (Manolopoulou et al., 2011)(Table 1). Rainwater samples collected in Krasnoyarsk on April27eMay 3, 2011 contained much lower concentrations of 131I andcesium isotopes (Table 1). Additional evidence for radioactivefallout at Krasnoyarsk due to the Fukushima Accident was found byanalyzing pine (P. sylvestris L.) needles collected on April 10, 2011and the membrane of the air filter that had worked for at leasta month by April 3, 2011. These samples, pine needles in particular,contained rather high levels of fission product radionuclides. Inpine needles, activity concentrations of 131I, 137Cs, and 134Csreached 3.28, 1.03, and 0.74 Bq/kg DW, respectively. The datareported by Calmon et al. (2009) suggest effective accumulation ofradiocesium by pine needles. In all Krasnoyarsk samples, the137Cs/134Cs ratio varied within a range of 0.79e1.8, and this range

was similar to that obtained for air samples collected in Greecebetween April 1 and 5, 2011: 1.2O 1.5 (Table 1). The 131I/137Cs ratiovaried within a range of 7.4e16.9 for water samples collected atKrasnoyarsk and was equal to 3.2 for both pine needles and the airfilter membrane. In order to interpret the results correctly, theactivity of 137Cs accumulated in pine needles before the accidentneeds to be deducted from the obtained activity concentrations.Based on previous measurements of 137Cs in the environmentalsamples collected at Krasnoyarsk (Dementyev and Bolsunovsky,2009) and estimated pre-accident 137Cs activity concentrations inpine needles, post-accident 137Cs concentration in pine needlesafter deduction of the global background value amounted to0.83 Bq/kg DW (Table 1). Radionuclide ratios did not changesignificantly after deduction of the background activity of 137Cs inpine needles (Table 1). The range of the 131I/137Cs ratios for theKrasnoyarsk samples (Table 1) was similar to that obtained forair samples in Greece: from 3.4 to 14.8 in April (Table 1) and up to18.4 in March 2011. The Greek scientists did not record cesiumisotopes in rainwater samples (Manolopoulou et al., 2011).Manolopoulou et al. (2011) reported measurements data of Japa-nese researchers, showing that in Japan the 137Cs/134Cs ratio wasequal to 0.97. This value, within the margin of error, is similar toour results obtained between April 4 and 6, 2011 (Table 1).

The obtained results show that fission products released inthe Fukushima Nuclear Accident were detected in the center ofAsia in AprileMay and the highest level of 131I in water (meltedsnow) collected after a snowfall in Krasnoyarsk (Russia) wassimilar to the level of 131I in water collected after a rainfall inGreece. The 137Cs/134Cs and 131I/137Cs ratios varied within thesame range for the samples collected in Greece and Russia,suggesting a high-velocity movement of radioactive contami-nation. The cloud containing radioactivity evidently movedtoward the Russian Far East and Japan, and, hence, it had trav-eled around the Earth. Thus, the detections of radiocesium andradioiodine in environmental samples in North America (USA),Europe, and Asia (Russia) prove the global effects of the nuclearaccident at Fukushima, similar to those caused by the Chernobylaccident.

Acknowledgments

The authors acknowledge the work of researchers of the Insti-tute of Biophysics SB RAS (Yu. Alexandrova) and the Institute ofForest SB RAS, who took part in sample collection and preparationfor measurements.

A. Bolsunovsky, D. Dementyev / Journal of Environmental Radioactivity 102 (2011) 1062e10641064

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