Radionuclides from Fukushima accident in Thessaloniki, Greece (40°N) and Milano, Italy (45°)

¹³¹I, ¹³⁷Cs and ¹³⁴Cs were observed in environmental samples in Milano (40°N), Italy and Thessaloniki (45°N), Greece, soon after the nuclear accident in Fukushima, Japan. The radionuclide concentrations were determined and studied as a function of time. In Thessaloniki the ¹³¹I in air was observed for the first time on March 24, 2011. In Milano, the first evidence of Fukushima fallout has been confirmed with ¹³¹I and ¹³⁷Cs measured in wet precipitation collected 2 days later. The maximum ¹³¹I activity concentration in air of 467 ± 25 μBq m^?3, observed in Milano on April 3–4, 2011, was almost similar to the highest value of 497 ± 53 μBq m^?3 observed in Thessaloniki. The ¹³⁴Cs/¹³⁷Cs activity ratio values in air were around 1 in both regions. Soil, grass and milk samples were contaminated with ¹³¹I and ¹³⁷Cs at a low level. Finally, a dose assessment for these two areas showed clearly that the detected activities in all environmental samples were far below levels of concern.     

Monitoring the environmental contamination of Kara Sea and shallow bays of Novaya Zemlya

The distribution of ¹³⁷Cs and ^239,240Pu in various ecosystems of the Kara Sea as well as speciation of these radionuclides has been studied to assess their potential mobility. In bottom sediment and seawater samples collected in Abrosimov, Tsivolky, Stepovoy, and Sedov Bays and on the coast of Novaya Zemlya, the content of anthropogenic radionuclides ¹³⁷Cs and ^239,240Pu does not exceed the values typical of the offshore zone in the Kara Sea (in sea water: 1.0–3.7 Bq/m³ for ¹³⁷Cs and 50–90 mBq/m³ for ^239,240Pu; in bottom sediments: 0.5–18.3 Bq/kg for ¹³⁷Cs and 4.3–7.3 Bq/kg for ^239,240Pu). The present monitoring study is important for the development of a long-term forecast for the dynamics of environmental contamination in the shallow bays of Novaya Zemlya.     

On variations of volumetric activity of 90Sr and 137Cs in the Baltic Sea coastal waters near the shore of Lithuania in 2005–2009

The article presents the measurement results of the volumetric activity (VA) of artificial radionuclides ⁹⁰Sr and ¹³⁷Cs in the coastal waters of the Baltic Sea near the Curonian Peninsula in 2005–2009. The annual average values for this period of time were 12 Bq/m³ (⁹⁰Sr) and 40 Bq/m³ (¹³⁷Cs). Considerable variations in the VA of the radionuclide in individual measurements compared to the average results were observed. The extreme values were 6 and 16 Bq/m³ for ⁹⁰Sr and for ¹³⁷Cs—27 and 75 Bq/m³. It is proposed to allow such variations under the influence of a variety of external factors such as hydro meteorological situations, inflowing rivers and bays, storm activity and etc. Besides, a possibility of penetration of radionuclides into the sea waters from the additional radioactive sources is not excluded.     

Environmental radioactivity measurements in north–western Greece following the Fukushima nuclear accident

The impact of the Fukushima nuclear accident in north–western Greece was assessed through an environmental monitoring programme activated by the Nuclear Physics Laboratory of the University of Ioannina. Measurements of ¹³¹I were carried out in atmospheric particulate, ovine milk and grass samples. In daily aerosol samplings, radioiodine was first detected on March 25–26, 2011 and reached maximum levels, up to 294 μBq m^?3, between April 2 and April 4, 2011. In ovine milk samples, ¹³¹I concentrations ranged from 2.0 to 2.7 Bq L^?1 between April 2 and April 6, 2011, while an average activity of 2.7 Bq kg^?1 was measured in grass samples on April 4, 2011. The ^134,137Cs isotopes were below detection limits in all samples and could only be determined in the air, by analysis of multiple daily filters. A maximum average activity concentration of ¹³⁷Cs amounting to 24 μBq m^?3 was measured during the period from April 5 to April 9, 2011, with the ¹³⁴Cs/¹³⁷Cs activity ratio being close to unity. Activity concentrations were consistent with measurements conducted in other parts of the country and were well below those reported in May 1986 after the Chernobyl accident. The committed effective dose to the whole body and to the thyroid gland from inhalation of ¹³¹I was estimated for the adult and infant population and was found to be of no concern for the public health.     

Measurement of fallout with rain in Hiroshima and several sites in Japan from the Fukushima reactor accident

Fallout with rain from the Fukushima reactor accident was monitored for about two months in Higashi-Hiroshima City, Hiroshima, Japan, from March 20 to May 23, 2011. Gamma-ray (γ-ray) spectra measured using a low background HPGe spectrometer showed clear evidence of fission products—¹³¹I, ¹³⁷Cs, and ¹³⁴Cs. The ¹³¹I was observed on March 27 and April 8, while ¹³⁷Cs and ¹³⁴Cs were observed on March 27, April 18, and April 22. The ¹³¹I, ¹³⁷Cs, and ¹³⁴Cs activity concentrations in rainwater collected in Hiroshima reached 0.44 ± 0.09 on April 8, 0.17 ± 0.01 on April 18, and 0.15 ± 0.01 Bq/L on April 18, 2011, respectively. These activity levels were compared with global results collected from the Northern Hemisphere. Several samples of rainwater that were collected in Chiba (Kashiwa) on March 21, April 11, and May 12; Tokyo (Nerima) on March 21 and April 11; Osaka (Hirano) on April 8; Nara (Kitakatsuragi) on April 9; and Fukushima (Fukushima) on April 19, were also measured by our spectrometer and compared. Among these samples of rainwater collected at different locations in Japan, the one collected at Kashiwa City, Chiba Prefecture, on March 21 showed the highest activity concentrations of 6072 ± 1,   632 ± 4,   766 ± 3,   637 ± 1,   97.6 ± 0.8, and 752 ± 2 Bq/L for ¹³¹I,   ¹³²I,   ¹³²Te,   ¹³⁴Cs,   ¹³⁶Cs, and ¹³⁷Cs, respectively. The health risks due to these high activity levels were considered in terms of several regulations. The ratio of the activites for the isotopes ¹³¹I to ¹³⁷Cs and ¹³⁴Cs to ¹³⁷Cs were compared with the other measurements and discussed.     

238Pu, 239+240Pu, 241Am, 90Sr and 137Cs in mountain soil samples from the Tatra National Park (Poland)

Activity concentrations and inventory for ²³⁸Pu, ^239+240Pu, ²⁴¹Am, ⁹⁰Sr, and ¹³⁷Cs in soil from Tatra Mountains of Poland are presented. Soil samples were collected using 10 cm diameter cores down to 10 cm and sliced into 3 slices. Details of the applied procedure are described with the quality assurance program. The maximum activity concentrations found for various samples were: 1782±13 Bq/kg, 17.4±0.9 Bq/kg, 3.4±0.3 Bq/kg and 84±7 Bq/kg for ¹³⁷Cs, ^239+240Pu, ²⁴¹Am and ⁹⁰Sr, respectively. The maximum cumulated deposition of ^239+240Pu is 201±8 Bq/m². The origin of radionuclides is discussed, based mostly on the observed isotopic ratio of Pu. Significant correlations were found between ^239+240Pu, ²⁴¹Am and ¹³⁷Cs. The effective vertical migration rate seems to be in the order of: ⁹⁰Sr≫Pu>Am>Cs.     

The ambient gamma dose-rate and the inventory of fission products estimations with the soil samples collected at Canadian embassy in Tokyo during Fukushima nuclear accident

In this study, soil samples were collected at Canadian embassy in Tokyo (about 300 km from Fukushima) on 23 March and 23 May of 2011 for purposes of estimating concentrations of radionuclides in fallout, the total fallout inventory, the depth distribution of radionuclide of interest and the elevated ambient gamma dose-rate at this limited location. Some fission products and actinides were analyzed using gamma-ray spectrometry, alpha spectrometry and liquid scintillation counting. The elevated activity concentration levels of ¹³¹I, ¹³²I, ¹³⁴Cs, ¹³⁷Cs, ¹³⁶Cs, ¹³²Te, ¹²⁹mTe, ¹²⁹Te, ¹⁴⁰Ba and ¹⁴⁰La were measured by the gamma-ray spectrometer in the first sample collected on 23 March. Two months after the accident, the ¹³⁴Cs and ¹³⁷Cs became only detectable nuclides. A mass relaxation depth of 3.0 g/cm² was determined by the activities on the depth distribution of ¹³⁷Cs in a soil core. The total fallout inventory was thus calculated as 225 kBq/m² on March sampling date and 25 kBq/m² on May sampling date. The ambient gamma dose-rates in the sampling area estimated by the fallout fission products inventory and ¹³⁷Cs depth distribution ranged from 184 to 38 nGy/h. There was no detectable americium or plutonium in the soil samples by alpha spectrometry. Although ⁹⁰Sr or ⁸⁹Sr were detected supposedly as a result of this accident, it was less than the detection limit, which was about 0.4 Bq/kg in the soil samples.     

Radon concentrations in kindergartens and schools in two cities: Kalisz and Ostrów Wielkopolski in Poland

Plastic PicoRad detectors with activated charcoal have been used for radon monitoring in local kindergartens and schools in two cities, Kalisz and Ostrów Wielkopolski, in the region of Greater Poland. Detectors were exposed for a standard time of 48 h during the autumn and winter of 2011 in 103 rooms (Kalisz) and 55 rooms (Ostrów Wlkp), respectively. The detectors were calibrated in the certified radon chamber of the Central Laboratory for Radiological Protection in Warsaw, Poland. The arithmetic and geometric means of indoor radon concentrations in the examined rooms were 46.0 and 30.3 Bq/m³ for Kalisz and 48.9 and 29.8 Bq/m³ for Ostrów Wlkp, respectively. The measured levels of the indoor radon concentrations were relatively low, since the main source of indoor radon for these low storey (max. three storeys) buildings is radon escaping from the underlying soil with a low ²²⁶Ra concentration (~15 Bq/m³). Therefore, the calculated annual effective doses from that source for the children in Kalisz and Ostrów Wlkp were also low 0.35 mSv.     

Ultra-low background measurements of decayed aerosol filters

Aerosol samples collected on filter media were analyzed using HPGe detectors employing varying background-reduction techniques in order to experimentally evaluate the opportunity to apply ultra-low background measurement methods to samples collected, for instance, by the Comprehensive Test Ban Treaty International Monitoring System (IMS). In this way, realistic estimates of the impact of low-background methodology on the sensitivity obtained in systems such as the IMS were assessed. The current detectability requirement of stations in the IMS is 30 μBq/m³ of air for ¹⁴⁰Ba, which would imply ~10⁶ fissions per daily sample. Importantly, this is for a fresh aerosol filter. One week of decay reduces the intrinsic background from radon daughters in the sample allowing much higher sensitivity measurement of relevant isotopes, including ¹³¹I. An experiment was conducted in which decayed filter samples were measured at a variety of underground locations using Ultra-Low Background (ULB) gamma spectroscopy technology. The impacts of the decay and ULB are discussed.     

Determination of137Cs and134Cs in air samples collected near Belgrade /Yugoslavia/ following the Chernobyl accident

This paper presents the results of measurements of¹³⁷Cs and¹³⁴Cs content in air sampled during May 1986. Maximum concentrations:¹³⁷Cs 2.94±0.01 Bq m^–3 and¹³⁴Cs 1.38±0.01 Bq m^–3 were registered on May 3. Several other long lived radionuclides having -energies in the region 33 keV to 1365 keV were registered in the same samples two years later. The results of measurements of the total -activity in air for the same period are also presented.     

Levels and effects of natural radionuclides in soil samples of Garhwal Himalaya

Distribution of natural radionuclide gives significant parameter to assess the presence of gamma radioactivity and its radiological effect in our environment. Natural radionuclides are present in the form of ²²⁶Ra, ²³²Th and ⁴⁰K in soil, rocks, water, air, and building materials. Distribution of natural radionuclides depends on the type of minerals present in the soil and rocks. For this purpose gamma spectrometer is used as tool for finding the concentration of these radionuclides. The activity concentration of naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in these soil samples were found to vary from of 8 ± 1 Bq/kg to 50 ± 10 Bq/kg with an average 20 Bq/kg, 7 ± 1–88 ± 16 Bq/kg with an Average 26 Bq/kg and 115 ± 18–885 ± 132 Bq/kg with an average 329 Bq/kg, respectively. In this paper, we are presenting the radiological effect due to distribution of natural radionuclide present in soil of Garhwal Himalaya.     

Input of 129I into the western Pacific Ocean resulting from the Fukushima nuclear event

We present an initial characterization of the input of ¹²⁹I into the Pacific Ocean resulting from the 2011 Fukushima nuclear accident. This characterization is based primarily on ¹²⁹I measurements on samples collected from a research cruise conducted in waters off the eastern coast of Japan in June 2011. These measurements were compared with samples intended to reflect pre-Fukushima background that were collected during a May 2011 transect of the Pacific by a commercial container vessel. In surface waters, we observed peak ¹²⁹I concentrations of ~300 μBq/m³ which represents an elevation of nearly three orders of magnitude compared to pre-Fukushima backgrounds. We coupled our ¹²⁹I results with ¹³⁷Cs measurements from the same cruise and derived an average ¹²⁹I/¹³⁷Cs activity ratio of 0.442 × 10^?6 for the effluent from Fukushima. Finally, we present ¹²⁹I depth profiles from five stations from this cruise which form the basis for future studies of ocean transport and mixing process as well as estimations of the total budget of ¹²⁹I released into the Pacific.     

Semi-quantitative analysis of leaf surface contamination by radioactivity from the Fukushima Daiichi nuclear power plant accident using HPGe and imaging plate

After the nuclear power plant accident at Fukushima Daiichi on 11 March 2011, green-leaves from trees, dead-leaves and grass on ground were collected from March to June 2011 in Japan. Radioactive concentrations were measured by a high purity germanium detector. Five radionuclides including ^129mTe, ¹³²Te, ¹³¹I, ¹³⁴Cs and ¹³⁷Cs were detected. The fission product concentration of the dead-leaves was higher than those of the green-leaves in many cases. The highest concentration observed was found on the dead-leaves collected at Iwaki, 60 km far from Fukushima Daiichi. A total activity of 2,000 Bq g^?1 was measured for all 5 radionuclides. Clear images of radioactivity of the highly contaminated leaves were obtained with an imaging plate (IP) after <24 h exposure time without using a shielded box. The photostimulated luminescence values (PSL) of leaves arranged on half size of IP were roughly in proportion to their activities except for the low activity samples. Semi-quantitative analysis was possible by using PSL values with a large region of interest of half size of IP, because the radioactivity released in the case of the nuclear power plant accident was uniform in the early days.     

Radioactivity of plutonium isotopes, <Superscript>137</Superscript>Cs and their ratio in sediment,seawater and biota from the east coast of Peninsular Malaysia

This study with sampling expeditions of marine sediment, seawater and biota were performed at 30 stations within Malaysian Exclusive Economic Zone (EEZ). A total of >400 samples were collected to determine the activity concentration of anthropogenic radionuclides (^239+240Pu, ¹³⁷Cs) and their activity ratio (^239+240Pu/¹³⁷Cs) in sediments, seawater and biota. The purpose of this study was to determine the concentration levels for these radionuclides and to evaluate any occurrence of radioactive contamination. Sediment cores were obtained using multicorer device, while water samples via co-precipitation techniques and biota was purchased from local fishermen. The activity concentrations of ^239+240Pu in sediment, seawater and biota were ranged 0.21–0.45 Bq/kg dry wt., 2.33–7.95 mBq/m³ and <0.008 Bq/kg fresh wt., respectively. Meanwhile, the values of ¹³⁷Cs were ranged <1.00–2.71 Bq/kg dry wt. in sediment, 3.40–5.89 Bq/m³ in seawater and <0.05–0.41 Bq/kg fresh wt. in biota, respectively. Activity ratios of ^239+240Pu to ¹³⁷Cs obtained seem to confirm that these artificial radioactivities were mainly due to global nuclear fallout.     

Cosmogenic 22Na, 7Be and terrestrial 137Cs, 40K radionuclides in ground level air samples collected weekly in Kraków (Poland) over years 2003–2006

A low background gamma spectrometer with an Etruscan, 2500 years old lead shield and a muon veto detector were applied to study ²²Na and ⁷Be activity concentration in ground level air aerosol samples collected weekly over the years 2003–2006 in Kraków. Each sample was formed with ca 100 000 m³ of passed air, collected with two parallel ASS-500 high volume air samplers. The results for ⁴⁰K and ¹³⁷Cs are also presented for reference and comparison. Presented frequency distributions for activity concentration and correlation between the obtained results are discussed. The activity concentration results confirmed seasonal variation of activity to be different for all the investigated radionuclides. Moreover, the seasonal variation in nucleus activity ratio was also noticed for ²²Na and ⁷Be. Cosmogenic radionuclides being mainly of stratospheric origin, are subsequently attached to fine aerosols, via which they are transported to the ground level air. The mean aerosol transport time within the troposphere was estimated as equal to 7.5 days on average, reaching even 50 days in warm seasons. Limitations of the applied model were identified.     

Intercomparison of phosphorus-32, technetium-99m and iodine-131 activity measurement in Pakistani nuclear medical centers and supplier

Technetium-99m and iodine-131 are the leading isotopes used in diagnosis and radiotherapy, respectively in Pakistani nuclear medical centers. Both radionuclides are regularly supplied by Isotope Production Division (IPD), PINSTECH to nuclear medical centers in Pakistan. The packages of ³²P, ⁹⁹Mo → ^99mTc generators, and ¹³¹I, are prepared at IPD and dispatched by air, rail or road according to the desired activity at reference day to nuclear medical centers. An accurate determination of the activity to be administered to the patient plays key role on the quality of the clinical result of a medical investigation. Activity meters are employed for quantification of radioactivity of radionuclides at supplier site as well as by the users. In order to investigate the performance on the quality of activity measurements and elution efficiency of PAKGEN ^99mTc generators, a pilot program of intercomparison was organized between the supplier and the users. The results of intercomparison of the activity measurements showed a maximum difference of ±13 % between supplier and nuclear medical centers.     

Outdoor 222Radon concentrations monitoring in relation with particulate matter levels and possible health effects

Air quality monitoring could potentially improve exposure estimates for use in epidemiological studies. We investigated air quality by monitoring concentrations of ²²²Rn near the ground and particulate matter (PM) with an aerodynamic diameter less than or equal to 10 μm (PM10) and 2.5 μm (PM2.5) for Bucharest-Magurele periurban area. Atmospheric radon concentrations have been continuously monitored near the ground at 1 m height as well as at 10 m height. This paper presents time-series of radon concentrations monitoring in air near the ground measured during 1 January 2011–1 January 2012 by use of solid state nuclear track detectors SSNTD CR-39, exposed for 10 days periods. The daily average atmospheric radon concentration near the ground registered at 1 m height was found to be in range of 40.25 ± 7.53 Bq/m³, which was comparable with the daily average radon concentration of 44.92 ± 9.94 Bq/m³ recorded for period 1 August 2011–20 December 2011 at 10 m height by AlphaGUARD Radon monitor. Also, was done a comparative analysis of spatio-temporal variations in time series of outdoor radon concentration and PM in two size fractions (PM10 and PM2.5) in Bucharest Magurele area for 2011 year. The predominant recorded component in PM10 was PM2.5. Observational results show that recorded yearly average PM2.5 and PM10 concentrations were 35.96 μg/m³ and 40.91 μg/m³, respectively. The average ratio of PM2.5/PM10 was 87.9 % at this sampling site. However, in densely populated Bucharest urban and suburban areas the mean daily EC limit values for PM10, PM2.5 and attached ²²²Rn are frequently exceeded leading to serious public concern during the last years. The ambient air pollution measurements like as PM10 and PM2.5 levels are used as a proxy for personal exposure levels. Have been investigated also meteorological effects on the temporal patterns of atmospheric radon and particle matter.     

High pressure Marinelli for counting low activity compressed gas samples

Quantification of low-activity noble gases in air is typically accomplished through separation of the noble gas from air followed by radiometric assay. This work is aimed at quantification of radioactive noble gas in air without extraction. A high pressure aluminum Marinelli counting vessel was designed and fabricated that can be placed on a coaxial high purity germanium detector for gamma counting. Characterization of the performance of this Marinelli using MCNP modeling, large excesses of activity, and low-activity noble gas in air is discussed. Minimum detectable concentrations achieved during a 24 h count are: 5, 10, 50, and 1 Bq/m³ for ¹³³Xe, ^133mXe, ^131mXe, and ¹³⁵Xe, respectively.     

Fabrication and characterization of electrochemical double layer capacitors using ionic liquid-based gel polymer electrolyte with chemically treated activated charcoal electrodes

The present investigation deals with electrochemical double layer capacitors (EDLCs) made up of ionic liquid (IL)-based gel polymer electrolytes with chemically treated activated charcoal electrodes. The gel polymer electrolyte comprising of poly(vinylidine fluoride-co-hexafluropropylene) (PVdF-HFP)–1-ethyl-2,3-dimethyl-imidazolium-tetrafluroborate [EDiMIM][BF₄]–propylene carbonate (PC)–magnesium perchlorate (Mg(ClO₄)₂) exhibits the highest ionic conductivity of ~8.4?×?10^?3?S?cm^?1 at room temperature (~20 °C), showing good mechanical and dimensional stability, suitable for their application in EDLCs. Activation of charcoal was done by impregnation method using potassium hydroxide (KOH) as activating agent. Brunauer–Emmett–Teller (BET) studies reveal that the effective surface area of treated activated charcoal powder (1,515 m²?g^?1) increases by more than double-fold compared to the untreated one (721 m²?g^?1). Performance of EDLCs has been tested using cyclic voltammetry, impedance spectroscopy, and charge–discharge techniques. Analysis shows that chemically treated activated charcoal electrodes have almost triple times more capacitance values as compared to the untreated one.     

The study on radioactive contamination in foodstuffs imported from Japan after the Fukushima accident

During the Fukushima nuclear accident, a large number of radionuclides were released, causing direct radioactive contamination to the environment and the ecosystem, and eventually indirect contamination to the foodstuffs. The Radiation Monitoring Group, Office of Atoms for Peace (OAP) in cooperation with the Food and Drug Administration (FDA), has been monitoring the foodstuffs imported from Japan, especially the Fukushima and nearby areas. This monitoring program covered the potentially contaminated foodstuffs. The measurements were mainly conducted using Gamma spectroscopy systems in order to analyze the radioactive concentration of ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs fission products. From 442 samples collected between after the nuclear accident to the end of September 2012, 28 of contaminated food products of fission isotopes have been found with the contamination ranges of 0.63–15.25 Bq/kg fresh, 1.45–44.70 Bq/kg fresh, and 0.45–51.10 Bq/kg fresh) for ¹³¹I, ¹³⁴Cs, and ¹³⁷Cs, respectively. However, the contamination levels are still well under the Thailand standard of food contaminated with radionuclide and the relevant international standards. Finally, the research also investigated the relationship between the times the samples were collected and the contamination levels.