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Monitoring of aerosol and fallout radioactivity in belgradeafter the fukushima reactors accident
 

Monitoring of aerosol and fallout radioactivity in belgradeafter the fukushima reactors accident

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    Monitoring of aerosol and fallout radioactivity in belgradeafter the fukushima reactors accident Monitoring of aerosol and fallout radioactivity in belgradeafter the fukushima reactors accident Document Transcript

    • Water Air Soil Pollut (2012) 223:4823–4829DOI 10.1007/s11270-012-1238-xMonitoring of Aerosol and Fallout Radioactivity in BelgradeAfter the Fukushima Reactors AccidentJelena Nikolic & Gordana Pantelic &Dragana Todorovic & Marija Jankovic &Maja Eremić SavkovicReceived: 29 November 2011 / Accepted: 12 June 2012 / Published online: 4 July 2012# Springer Science+Business Media B.V. 2012Abstract After the accident in Fukushima reactors, 1 Introductiona daily monitoring programme was initiated in twolaboratories in Belgrade, one at the Vinčа Institute The Fukushima Daiici nuclear power plant accidentfor Nuclear Sciences and the other at Institute for caused a large regional release of radionuclides intoOccupational Health Karajovic. Samples of aerosol the atmosphere and subsequent radioactive contami-and fallout, as well as the random samples of food nation of the environment. Once released into theand water, were collected and analysed, using atmosphere, long-range atmospheric transport pro-gross alpha/beta and gamma spectrometry, in order cesses can cause a widespread distribution of radioac-to establish the presence of traces of isotopes tive matter. The fallout consisting of short-lived andindicating Fukushima fallout. Gamma spectrometry long-lived radionuclides eventually affects humansmeasurement of these samples showed clear evi- either directly or indirectly by entering the food chaindence of fission products 131I, 134Cs and 137Cs through plants and animals.wtihin 2 weeks after the accident. The activity dimin- The radioactive contamination originating fromished with time due to dispersion in air and, in Fukushima was detected not only in Japan and Asia,case of 131I, short half-life. but also in the entire northern hemisphere, including USA and Europe (Chino et al. 2011; Diaz Leon et al. 131Keywords I . 134Cs . 137Cs . Aerosols . Fallout 2011; Manolopoulou et al. 2011; Pittauerová et al. 2011; Wakeford 2011). The fallout spread from Fukushima across the Pacific ocean and American continent, then over the Atlantic ocean, and finally came to Europe,J. Nikolic (*) : G. Pantelic : D. Todorovic : M. Jankovic where it was first detected in Iceland and Scandinavia.University of Belgrade Vinča Institute of Nuclear Sciences, After that, all European countries reported detection ofMike Petrovića Alasa 12-14, the elements originating from Fukushima reactors.11001 Belgrade, Serbiae-mail: jnikolic@vinca.rs Serbia has developed a monitoring programme 60 years ago. The contents of radionuclides are deter-M. E. Savkovic mined in aerosol, soil, fallout (wet and dry deposition),Serbian Institute of Occupational Health rivers, lake and drinking water, human and animal food,“Dr Dragomir Karajović”,Deligradska 29, on monthly basis. This network and monitoring pro-11000 Belgrade, Serbia grammes were updated after the Chernobyl accident.
    • 4824 Water Air Soil Pollut (2012) 223:4823–4829As a first response to the Fukushima accident, five air century (Todorovic 2000). The results presented in thiscollection stations and three fallout collection stations, paper represent the investigation of daily measurementssituated in and around the Vinča Institute of Nuclear of aerosol filters from six stations, fallout and compositeSciences in Belgrade, were used for daily sample col- samples from five stations and random food and soillection (Popović 2007). Also, the Institute for Ocupa- samples obtained in the above-mentioned institutes.tional Health Karajovic analysed samples taken fromone air station situated in the centre of Belgrade andtwo fallout sampling sites in the nearby counties of 2 Materials and MethodsLazarevac and Obrenovac, producing a total of six airand five fallout sampling stations at the teritory of Air samples were collected daily, 1 m above groundBelgrade city region. Radionuclide content in aerosol by airflow pump, pumping the air trough the filterand fallout was determined both in daily and composite paper. At five locations (Table 1), F&J Digital Highmonthly samples. The coordinates and type of samplers Volume Environmental Air Sampling System DH-are given in Table 1 (samples from the locations named 60810 Ev.2 was used and aerosol samples were col-Vinča 1, Vinča 2, Vinča 3, Vinča 4 and Belgrade 2 were lected using Whatman 41/No.5A, 20×25-cm filteranalysed in the Vinca Institute of Nuclear Sciences, and papers, with relative efficiency of 81 % for depositedsamples from locations Belgrade 1, Lazarevac and dust. The samplers have constant flow rate, of averageObrenovac were analysed in the Institute for Ocupa- 30–50 m3/h. The Petrianov FPP-15-1.5 type filter 40×tional Health Karajovic). A more detailed plan of mon- 40 cm with relative efficiency of 96 to 99 % was useditoring is already in motion, and will include sample at one high volume ASS-500 station with average flowcollection from numerous stations distributed in other rate of 500 m3/h at the location Belgrade 2. The filtersparts of the country. were replaced every day at 8 a.m., covering a total After a nuclear accident, contamination of food and period from March 18 to April 30, 2011. Samples ofland can occur either from deposition of material origi- fallout (dry and wet precipitation) were collected innally introduced to atmosphere or through the food the container 1 m above of uncultivated soil at loca-chain. Because of that, random food and soil samples tions in the centre of Belgrade, the vicinity of Vinčawere analysed to confirm eventual presence of contam- Institute, Lazrevac and Obrenovac.ination. The food samples included green vegetables The air filter samples collected at five stations(spinach, greens and salad), cow and goat milk, grass (Vinča1, Vinča 2, Vinča 3, Vinča 4 and Belgrade 2)and clover for cattle feed. The soil samples were col- were cut in the form that corresponds to the measure-lected at the Danube and Danube confluents’ coasts. ment geometry and measured, without ashing, 5 h and It was expected that some traces of isotopes re- 5 days after sampling, on lowbackground alpha/betaleased from Fukushima accident should be detected proportonal counter Thermo Eberline FHT770T. Thein the last week of March, according to previous correction factor for the cut surface/total surface of theinvestigations of release from nuclear weapons tests filter paper was calculated, so that the final resultconducted in China in the mid-sixties of the twentieth represented the whole sample. The first measurementTable 1 The coordinates ofsampling sites, type of aerosol Station Coordinates Aerosol sampler Fallout Frequency ofsampler, fallout container container (m2) samplingarea and sampling frequencyfor the sampling stations Vinča 1 44°45′ N, 20°35′ E F&J System 0.16 Daily Vinča 2 44°45′ N, 20°36′ E F&J System – Daily Vinča 3 44°46′ N, 20°37′ E F&J System – Daily Vinča 4 44°44′ N, 20°36′ E F&J System – Daily Belgrade 1 44°48′ N, 20°28′ E ASS-500 station 0.1 Daily Belgrade 2 44°47′ N, 20°25′ E F&J System 1 Daily Lazarevac 44°23′ N, 20°16′ E – 0.1 Monthly Obrenovac 44°39′ N, 20°12′ E – 0.1 Monthly
    • Water Air Soil Pollut (2012) 223:4823–4829 4825produced the data on the total short- and long-lived Sciences by HP Ge detection systems Canberra, relativeradionuclides in air, and the second one produced the efficiency 23 %, and samples collected at the locationsdata on the activity of long-lived radionuclides only. Belgrade 1, Lazarevac and Obrenovac were mea-After the gross alpha and beta measurement at the day of sured at Institute of Occupational Health Karajovicthe collection, these five daily filters were combined to using ultra-low background HP Ge detection systemsform one composite sample and placed, without ashing, Ortec-Ametek, relative efficiency 40 %.into a plastic container. Composite daily sample wasmeasured by gamma spectrometry using HP Ge detec-tion systems Canberra, relative efficiency 23 %, resolu- 3 Results and Discussiontion 1.89 keV at 1,332 keV. At the end of the month,samples from each aerosol station were combined to The daily measurement of aerosol filters and falloutform mothly sample (i.e. 30 air samples from one station started on March 18, 2011, 6 days after the accident atwere combined in one composite monthly sample at that the Fukushima Daiici nuclear power plant. The grossstation) for gamma spectrometry measurement. alpha and beta activity in aerosol filters measured 5 h The air samples collected at the location Belgrade 1 after sampling did not show any increase of activitywere measured, without ashing, using ultra-low back- compared to measurements before the Fukushima ac-ground HP Ge detection systems Ortec-Ametek, relative cident (Todorovic et al. 1996). The ratio of gross betaefficiency 40 % and resolution 1.85 keV at 1,332 keV. activity/gross alpha activity in these measurement wasFallout smples were collected using a plastic foil cover- between 2 and 2.5 for the entire examination period,ing the fallout container. After collection of the daily except for the filters exposed from March 29 to 30,sample, the foil was placed into a plastic container and when this ratio was betwen 2.7 and 3.7 for filtersmeasured immediately without any other preparation in collected at all stations.order to aviod the loss of iodine. If there was any wet Time variation of gross beta activity concentrationprecipitation, the content of the foil was placed into a in aerosol samples measured 5 days after sampling atplastic bottle of 250 ml without evaporation. Composite five aerosol sampling stations measured by Vinčamonthly sample of the fallout was formed by collecting Institute of Nuclear Sciences is presented on Fig. 1.all daily samples from corresponding locations (except These measurements also showed the maximum betathe samples collected at Lazarevac and Obrenovac activity on filters exposed from March 29 to March 30.where monthly samples were obtained by exposing the The highest value of 3.6 mBq/m3 was measured atsampler to the precipitation during the whole month) aerosol filter collected at Vinča 3 station. This corre-and prepared by mineralization at 450 °C. Daily and sponds to the highest detected 131I activity in aerosolmonthly samples collected at the locations Vinča 1 and filters which will be shown later in this paper. ThisBelgrade 2 were measured at Vinča Institute of Nuclear peak of activity is expected, according to previousFig. 1 Time variation ofgross alpha beta activityconcentration in aerosol atlocations Vinča 1, Vinča 2,Vinča 3, Vinča 4 and Bel-grade 2, measured by VinčaInstitute of Nuclear Sciences5 days after sampling; theresults are given at two-sigma level of uncertainty
    • 4826 Water Air Soil Pollut (2012) 223:4823–4829Fig. 2 Time variation of131 I activity concentrationin daily aerosol samplesmeasured by Vinča Instituteof Nuclear Sciences (InstitutVinca) and measured by In-stitute for OccupationalHealth Karajovic (InstitutKarajovic), 5 h after sam-pling; the results are given attwo-sigma level ofuncertaintyexperience, to occur 15–20 days after the release of the samples from location Belgrade 1. The resultsradioactive contaminants, and here, this presumption obtained from the latter show higher values, presumablyis confirmed (Todorovic 2000). The dates on all fig- due to greater average flow rate at that station.ures correspond to days when the filters were changed During the first week of the measurement, only the 137on aerosol pumps. Cs activity was measurable, but that was estimated On March 23, the depostion of 131I was detected on to be a consequence the Chernobyl accident. Theaerosol samples (as it can be seen in Fig. 2) and the first average 137Cs activity in the first week was 1 μBq/detection of 134Cs occured on March 29 (shown in m3 which is at the same level as the value obtained inFig. 3). The highest activity observed for 131I in aerosol 2010. The average 137Cs activity in aerosol in Bel-was 1.6 mBq/m3 on March 29 and 30. 131I activity in grade in 2010 was 0.78 μBq/m3 with the maximumaerosol decreased after April 12. Figures 2 and 3 repre- value 1.8 μBq/m3 in March 2010 (Serbian Radiationsent the mean values obtained daily from composite Protection and Nuclear Safety Agency 2011).samples (as described in the Introduction section), The maximum value for 134Cs in aerosol waswhere Institut Vinca represents the composite samples 0.14 mBq/m3 on March 29 and 30 and 0.136 mBq/m3from locations Vinča 1, Vinča 2, Vinča 3, Vinča 4 and on April 8 and 9. The maximum values for 137CsBelgrade 2 (since those were measured at Vinča Institute in aerosol were 0.16 and 0.144 mBq/m3 at theof Nuclear Sciences) and Institut Karajovic represents same days (Fig. 4). According to the measurementFig. 3 Time variation of134 Cs activity concentrationin daily aerosol samplesmeasured by Vinča Instituteof Nuclear Sciences (InstitutVinca) and measured by In-stitute for OccupationalHealth Karajovic (InstitutKarajovic), 5 h after sam-pling; the results are given attwo-sigma level ofuncertainty
    • Water Air Soil Pollut (2012) 223:4823–4829 4827Fig. 4 Time variation of137 Cs activity concentrationin aerosol in daily aerosolsamples measured by VinčaInstitute of Nuclear sciences(Institut Vinca) and mea-sured by Institute for Occu-pational Health Karajovic(Institut Karajovic), 5 h aftersampling; the results aregiven at two-sigma level ofuncertaintyof KEK (2011), the 137Cs/134Cs ratio was aprox- concentration (MDC) which was 8.4 μBq/m3 andimately equal to unity. In our measurement, the 137 Cs below 6.4 μBq/m3.137 Cs/134Cs ratio was equal to 1.1, which shows Measured concentrations of 134Cs and 137Cs inpresence of 137Cs from Chernobyl accident. The composite monthly aerosol samples collected at allmeasurement results over the years showed that stations except Lazarevac and Obrenovac are pre-every winter and spring, there is a certain air sented in Table 2, at the uncertainty level of twoexchange between the stratosphere and the tropo- sigma. The results showed similar activity concentra-sphere, vertical mixing within the troposphere and tion ratio 137Cs/134Cs as it was in the daily measure-the washout effects, which leads to increasing of 137Cs ment. The measured 131I activity was below detectionactivity in aerosol (Todorovic 1997; Jankovic and limit, due to short half-life of iodine and because theTodorovic 2011). monthly samples represent mineralised daily filters, 134 Cs and 137Cs were first detected in aerosol sam- from which iodine dissapeared as a volatile element,ples collected at air sampling station Belgrade 1 (Figs. 3 and its value is not presented in Table 2.and 4) because the air flow rate at ASS 500 station is The time variation of 131I inventory in fallout col-much higher than on other sampling stations, and hence, lected at meterorological stations Vinča 1 and Bel-the perceptibility is greater. After April 23 the daily grade 1 is shown in Fig. 5. After April 17 the dailydeposition of 134Cs was below minimal detectable deposition of 131I was below 0.1 Bq/m2.Table 2 134Cs and 137Cs 134activity and their ratio in the Month Station Cs (μBq/m3) 137 Cs (μBq/m3) 137 Cs/134Csaerosol, monthly samples; theresults are given at two-sigma March Vinča 1 6.3±0.8 8±1 1.3level of uncertainty Vinča 2 12±1 14±2 1.2 Vinča 3 10±1 14±2 1.4 Vinča 4 14±2 16±2 1.1 Belgrade 1 28.0±0.2 32±1 1.1 Belgrade 2 11±2 12±2 1.1 April Vinča 1 27±3 36±4 1.3 Vinča 2 19±2 23±2 1.2 Vinča 3 20±2 24±2 1.2 Vinča 4 17±2 24±2 1.4 Belgrade 1 68±2 87±2 1.3 Belgrade 2 18±2 24±2 1.3
    • 4828 Water Air Soil Pollut (2012) 223:4823–4829Fig. 5 Time variation of131 I inventory in fallout inBelgrade, at locations Vinča1 measured by Vinča Insti-tute of Nuclear Sciences(Institut Vinca) and Bel-grade 1, measured by Insti-tute for Occupational HealthKarajovic (Institut Kara-jovic), 5 h after sampling;the results are given at two-sigma level of uncertainty 134 Cs inventory was below detection limit (MDC0 of some differences in the absolute values of ac-0.2 Bq/m2) in all monthly fallout samples, while 137Cs tivity concentrations, all results, obtained from allwas detected in two samples. MDC for 134Cs is rather samples and measured in both laboratories, showhigh due to small efficiency of the measurement similar pattern increase of values in time to theequipment in this energy region and small fallout maximum at about 15–20 days from the date ofcollecting area. The results are presented in Table 3 the release of contaminants and after that a slow(results for 134Cs were omitted since they all are below decrease, until the values are below MDC.MDC) with the uncertainty level of two sigma. The 131I and 134Cs activities were below detectionlimit in all food and soil samples, exept in one goat 4 Conclusionsmilk sample collected on March 30 in a village nearParaćin where 131I activity was (0.16 ±0.04) Bq/l. The Fukushima nuclear accident fission products were137 Cs activity was below detection limit in all food detected in the Republic of Serbia, regardless of thesamples, but because of its long half-life, it is detected great distance from Fukushima and the pathway of thein the soil samples and will remain for a long time air masses. The detected isotopes were 131I, 134Cs and 137as a consequence of Chernobyl (Pantelić et al. Cs with the highest activity observed for 131I in2000) rather than Fukushima accident. Regardless aerosol on March 29 and 30. Maximum values for 134 Cs and 137Cs in aerosol were also on March 29Table 3 137Cs inventory in fallout, monthly samples; the results and 30 and on April 8 and 9. The measured radionu-are given at two-sigma level of uncertainty clide concentrations in aerosols were three to four 137 orders of magnitude lower than the concentraton mea-Month Station Station Cs (Bq/m2) sured in Belgrade in 1986. after the Cernobyl accidentMarch Vinča 1 0.24±0.06 (Todorović 2000; FC 1989), which was expected be- Belgrade 1 <0.12 cause of the well-known dilution effects. Belgrade 2 <0.03 Reasonably good agreement between the measure- Lazarevac <0.35 ment activities of 131I, 134Cs and 137Cs was observed for Obrenovac <0.21 the levels measured in aerosol and fallout. The discrep-April Vinča 1 <0.18 ancies between the results obtained in two institutes are Belgrade 1 <0.24 due to different climate conditions and different relative Belgrade 2 0.21±0.03 efficiency of the measurement equipment. The 131I and 134 Lazarevac <0.44 Cs activities were below detection limit in all food Obrenovac <0.34 samples, except in one goat milk sample collected on March 30. From these results, we can conclude that the
    • Water Air Soil Pollut (2012) 223:4823–4829 4829contamination did occur but in amounts that are not ground level air. Water Air and Soil Pollution. doi:10.1007/considered threatening for the general population. s11270-011-0917-. KEK. (2011). Measurement result of airborne nuclide and air Since our measurements were carried out as a re- radiation level in Tsukumba Area (Japan): 3rd report.sponse to a potential threat from contamination and only High Energy Accelerator Research Organization, KEK,in a few locations that cover a small part of our country, Japan.the results should be regarded as a preliminary investi- Manolopoulou, M., Vagena, E., Stoulos, S., Ioannidou, A., & Papastefanou, C. (2011). Radioiodine and radiocesium ingation. The aim was to establish the method for fast Thessaloniki. Northern Greece due to the Fukushima nu-response and control in case of contamination. In that clear accident. Journal of Environmental Radioactivity,respect, the number of results obtained is not large 102(8), 796–797.enough for a more in-depth analysis, but can provide a Pantelić, G., Eremić-Savković, M., Vitorović, G., Vuletić, V., Tanasković, I., Javorina, Lj. (2000). Radionuclides activityvery useful insight, that is to be used for further refin- concentration in soil in Serbia. Proceedings of Third Euro-ment of the monitoring procedures. pean IRPA Congress, 14–16 June 2010, Helsinki, Finland, p 16–24, 1–4. Pittauerová, D., Hettwig, B., & Ficher, H. W. (2011). FukushimaAcknowledgments The investigation was partially supported fallout in Nothwest German environmental media.by the Ministry of Education and Science of the Republic of Journal of Environmental Radioactivity. doi:10.1016/Serbia under the following Project III43009. j.jenvrad.2011.06.003. Popović, D., Todorović, D., Spasic Jokić, V., & Djurić, G. (2007). Air radioactivity monitoring in Serbia. In B. O.References Gungor (Ed.), Environmetal tehnologies: New develop- ments (pp. 147–166). Vienna: I-Tech Education and Publishing.Chino, M., Nakayama, H., Nagai, H., Terada, H., Katata, G., & Serbian Radiation Protection and Nuclear Safety Agency Yamazawa, H. (2011). Preliminary estimation of release (2011). Report on the level of ionizing radiation environ- amounts of 131I and 137Cs accidentally discharged from mental exposure of population in the Republic of Serbia in the Fukushima Daiichi Nuclear Power Plant into the atmo- 2010. http://www.srbatom.gov.rs/srbatom/doc/Monitoring- sphere. Journal of Nuclear Science and Technology, 48(7), izvestaj.pdf. In Serbian. Accessed 12 June 2012. 1129–1134. Todorovic, D. (1997). The effect of tropopause height on theDiaz Leon, J., Jaffe, D. A., Kaspar, J., Knecht, A., Miller, M. L., content of radioactive debris in surface atmosphere. Envi- Robertson, R. G. H., & Schubert, A. G. (2011). Arrival ronmental International, 23(6), 815–818. time and magnitude of airborne fission products from the Todorović, D. (2000). Distribution of natural (7Be, 210Pb) and Fukushima, Japan, reactor incident as measured in artificial (137Cs) radionuclides in in ground level atmo- Seattle, WA, USA. Journal of Environmental Radioactivity. sphere and in the precipitated dust in urban areas. Faculty doi:10.1016/j.jenvrad.2011.06.005. of Physics, Belgrade. PhD thesis, in SerbianFC. (1989). Federal Committee for Labour, Health and Social Todorovic, D., Smiljanic, R., & Manic, S. (1996). Thirty years Policy. Environmental Radioactivity in Yugoslavia, data of air radioactivity monitoring in Vinca Institute. Ecolog- for 1986, Belgrade, in Serbian. ica, 10(2), 33–40. In Serbian.Jankovic, M., & Todorovic, D. (2011). Determination of sym- Wakeford, R. (2011). And now, Fukushima. Journal of Radio- metrical index for 3H in precipitation and 137Cs in logical Protection, 31, 167–176.