scholarly journals Activity of natural radionuclides and their contribution to the absorbed dose in the fish cubera snapper (lutjanus cyanopterus, cuvier, 1828) on the coast of Ceara, Brazil

2010 ◽  
Vol 58 (spe4) ◽  
pp. 25-32 ◽  
Author(s):  
Wagner de S. Pereira ◽  
Alphonse Kelecom ◽  
Delcy de A. Py Júnior
Keyword(s):  
Dose Rate ◽  
Standard Dose ◽  
Natural Radionuclides ◽  
Absorbed Dose ◽  
Threshold Value ◽  
Average Dose ◽  
Absorbed Dose Rate ◽  
Dose Rates ◽  
A Value ◽  
Lead 210

A methodology was developed for converting the activity concentration of radionuclides (Bq kg-1) into absorbed dose rate (Gy y-1), aiming an approach to environmental radioprotection based on the concept of standard dose limit. The model considers only the internal absorbed dose rate. This methodology was applied to the cubera snapper fish (Lutjanus cyanopterus, Cuvier, 1828) caught off the coast of Ceará. The natural radionuclides considered were uranium-238, radium-226, lead-210, thorium-232 and radium-228. The absorbed dose rates were calculated for individual radionuclides and the type of emitted radiation. The average dose rate due to these radionuclides was 5.36 µGy y-1, a value six orders of magnitude smaller than the threshold value of absorbed dose rate used in this study (3.65 10³ mGy y-1), and similar to that found in the literature for benthic fish. Ra-226 and U-238 contributed 67% and 22% of the absorbed dose rate, followed by Th-232 with 10%. Ra-228 and Pb-210, in turn, accounted for less than 1% of the absorbed dose rate. This distribution is somewhat different from that reported in the literature, where the Ra-226 accounts for 86% of the absorbed dose rate.

Absorbed dose rate assessment for the Japanese cedar stand affected after the Fukushima NPP accident.

2021 ◽  
Author(s):  
Rena Mikailova ◽  
Yuichi Onda ◽  
Sergey Fesenko ◽  
Hiroaki Kato
Keyword(s):  
Dose Rate ◽  
Water Content ◽  
Forest Ecosystem ◽  
Forest Ecosystems ◽  
Absorbed Dose ◽  
Japanese Cedar ◽  
Average Dose ◽  
High Concentration ◽  
Absorbed Dose Rate ◽  
Dose Rates

<p>The nuclear disaster from the FNPP accident resulted in the major contamination of forest ecosystem of Eastern Japan. Forests are the most susceptible to ionizing radiation exposure, especially conifers due to their high radiosensitivity and pollutant interception abilities. A high concentration of radionuclides in forest ecosystems caused an increase in the dose rate. Japanese cedar belongs to Japan's endemic species; therefore, the current study was aimed at the absorbed dose rate assessment of the C. japonica forest stand in the Yamakiya district. To estimate the absorbed dose rates to the Japanese cedar trees, we used the <sup>134,137</sup>Cs concentrations in different forest ecosystems’ compartments. The calculations include data from 2011 to 2017. The dose rate assessments were performed at different heights of the forest ecosystem (canopy, trunk, understory). The average dose rates decreased from 40 µGy/day in 2011 to 13 µGy/day in 2017. The assessment results comply with the ambient dose rate measured from 2011 to 2015. The assessment showed that the water content in the litter and topsoil layers significantly influence the formation of the dose rate. Via the model, we simulated the dose rates for 20% and 80% of the litter water content. The results showed that the average measured dose rates lie within the estimated results. Due to the lack of data on litter and soil moisture during sampling, now we are trying to calculate the ground layers’ water content using the available information on precipitation rate.</p>

scholarly journals Influences of Absorbed Dose Rate on the Mechanical Properties and Fiber–Matrix Interaction of High-Density Polyethylene-Based Carbon Fiber Reinforced Thermoplastic Irradiated by Electron-Beam

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3012
Author(s):  
Se Kye Park ◽  
Dong Yun Choi ◽  
Duyoung Choi ◽  
Dong Yun Lee ◽  
Seung Hwa Yoo
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Carbon Fiber ◽  
Dose Rate ◽  
High Density Polyethylene ◽  
Absorbed Dose ◽  
High Density ◽  
Absorbed Dose Rate ◽  
Dose Rates ◽  
Absorbed Dose Rates

In this study, a high-density polyethylene (HDPE)-based carbon fiber-reinforced thermoplastic (CFRTP) was irradiated by an electron-beam. To assess the absorbed dose rate influence on its mechanical properties, the beam energy and absorbed dose were fixed, while the absorbed dose rates were varied. The tensile strength (TS) and Young’s modulus (YM) were evaluated. The irradiated CFRTP TS increased at absorbed dose rates of up to 6.8 kGy/s and decreased at higher rates. YM showed no meaningful differences. For CFRTPs constituents, the carbon fiber (CF) TS gradually increased, while the HDPE TS decreased slightly as the absorbed dose rates increased. The OH intermolecular bond was strongly developed in irradiated CFRTP at low absorbed dose rates and gradually declined when increasing those rates. X-ray photoelectron spectroscopy analysis revealed that the oxygen content of irradiated CFRTPs decreased with increasing absorbed dose rate due to the shorter irradiation time at higher dose rates. In conclusion, from the TS viewpoint, opposite effects occurred when increasing the absorbed dose rate: a favorable increase in CF TS and adverse decline of attractive hydrogen bonding interactions between HDPE and CF for CFRTPs TS. Therefore, the irradiated CFRTP TS was maximized at an optimum absorbed dose rate of 6.8 kGy/s.

scholarly journals Estimation of radioecological parameters of soil samples from a phosphatic area

2016 ◽  
Vol 31 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Shaaban Harb ◽  
Noor Ahmed ◽  
Wael Badawy ◽  
Nagwa Saad
Keyword(s):  
Dose Rate ◽  
Annual Effective Dose ◽  
Natural Radionuclides ◽  
Significant Risk ◽  
Absorbed Dose ◽  
Soil Samples ◽  
Absorbed Dose Rate ◽  
Activity Concentrations ◽  
Average Activity ◽  
Range Of Values

The activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) for a set of 31 agricultural soil samples from the Nile River banks in the area of El-Sebaiya city, Aswan Governorate, Egypt were measured by gamma-spectrometry. The study revealed that the average activity concentrations of natural radionuclides 226Ra, 232Th, and 40K were 23.2 ? 2.8Bq/kg, 21.1 ? 2.8 Bq/kg, and 218.6 ? 3.7 Bq/kg, respectively. The obtained results of the activity concentrations are within the range of values reported for neighbouring areas in Egypt. The values obtained for the hazard indices and the representative level index in all sampling sites were lower than unity, showing that there is no significant risk arising from the exposure to the soil in the studied area. The absorbed dose rate and annual effective dose in air outdoors and indoors were calculated from 226Ra, 232Th, and 40K in soil, the average values being 32.64 nGy/h, 40.06 ?Sv, and 160.25 ?Sv, respectively. The absorbed dose rate at the eastof El-Sebaiya city is higher than that obtained for the west because of higher concentrations of tri-calcium phosphate in the soil. The studied area is not significantly affected by the industrial activities, except for a few isolated spots.

CHANGES OF ABSORBED DOSE RATE IN AIR BY CAR-BORNE SURVEY IN NAMIE TOWN, FUKUSHIMA PREFECTURE AFTER THE FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT

2019 ◽  
Vol 184 (3-4) ◽  
pp. 527-530 ◽  
Author(s):  
Y Shiroma ◽  
M Hosoda ◽  
K Iwaoka ◽  
M Hegedűs ◽  
H Kudo ◽  
...  
Keyword(s):  
Power Plant ◽  
Dose Rate ◽  
Nuclear Power ◽  
Absorbed Dose ◽  
Local Distribution ◽  
Absorbed Dose Rate ◽  
Distribution Maps ◽  
Dose Rates ◽  
Fdnpp Accident ◽  
Fukushima Daiichi

Abstract The latest car-borne survey was carried out by Hirosaki University in order to grasp the local distribution of the absorbed dose rate in air after the evacuation order was lifted on Namie Town in 2017. The car-borne survey of absorbed dose rate in air was carried out on most of the roads which were accessible by car in Namie Town using a 3-in × 3-in NaI(Tl) scintillation spectrometer. The range of the absorbed dose rate in air was calculated to be 0.041–11 μGy h−1. The distribution maps of the absorbed dose rate in air were drawn based on the data obtained during the surveys in 2011, 2015 and 2017. The comparison of these absorbed dose rates in air suggests that the elevated absorbed dose rate in air in Namie Town caused by the FDNPP accident may be decreasing faster than natural decline which includes weathering effect and physical decay due to the artificial decontamination.

EVALUATION OF INDOOR/OUTDOOR GAMMA EXPOSURE RATES AND EXCESS LIFE TIME CANCER RISK IN DIFFERENT CITIES OF PAKISTAN

2020 ◽  
Vol 190 (4) ◽  
pp. 355-363
Author(s):  
Jahan Zeb ◽  
Mohammad Wasim ◽  
Muhammad Awais ◽  
Asad Ullah ◽  
Talat Iqbal ◽  
...  
Keyword(s):  
Cancer Risk ◽  
Dose Rate ◽  
Absorbed Dose ◽  
Life Time ◽  
Absorbed Dose Rate ◽  
Detailed Measurement ◽  
Dose Rates ◽  
The Mean ◽  
Azad Kashmir ◽  
Indoor And Outdoor

Abstract This study presents a detailed measurement of indoor and outdoor terrestrial gamma radiation levels in different cities of Pakistan. The measurements covered dwellings in 27 cities, covering all provinces and region of Azad Kashmir. Most of the houses were of attached type, made of brick walls and concrete roofs. The measurements were made by a handheld radiation survey meter containing Geiger–Muller tube. The average absorbed dose rate in air was 100 ± 32 nGy h−1 for indoor and 74 ± 30 nGy h−1 for outdoor. The population-weighted mean terrestrial dose rates were 90 nGy h−1 for indoor and 78 nGyh−1 for outdoor. The ratio of indoor to outdoor absorbed dose rate was 1.5 as compared to 1.3 for the world average. The estimated average annual effective dose rate was 0.58 ± 0.18 mSv a−1 and the mean excess life time cancer risk was 2.0 × 10−3.

IMPACT ON ABSORBED DOSE RATE IN AIR IN KANTO REGION BY FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT

2019 ◽  
Vol 184 (3-4) ◽  
pp. 500-503
Author(s):  
K Inoue ◽  
M Arai ◽  
H Tsuruoka ◽  
K Saito ◽  
M Fujisawa ◽  
...  
Keyword(s):  
Dose Rate ◽  
Nuclear Power ◽  
Absorbed Dose ◽  
Ground Level ◽  
Absorbed Dose Rate ◽  
Artificial Radionuclides ◽  
Dose Rates ◽  
The Mean ◽  
Absorbed Dose Rates ◽  
Kanto Region

Abstract Absorbed dose rates in air were measured for the whole area of the Kanto region in 2015, 2016 and 2017 (n = 31 147). The mean absorbed dose rates in air for each prefecture measured by car-borne surveys were from 44 to 67 nGy h−1 (13–289 nGy h−1). The absorbed dose rate in air from artificial radionuclides (134Cs + 137Cs) measured by fixed-point observation (n = 507) was from 1 to 14 nGy h−1 (0–105 nGy h−1), and meaning that the contribution ratios of 134Cs and 137Cs were 3–22%. The deposited location of artificial radionuclides was less than 1000 m from ground level and depended on the topography, wind direction and precipitation field.

Natural gamma radiation in La Palma Island, Canary Islands, Spain

2020 ◽  
Author(s):  
María López-Pérez ◽  
Pedro Ángel Salazar-Carballo ◽  
M. Candelaría Martín-Luis ◽  
José Miguel Lorenzo-Salazar ◽  
Xiomara Duarte-Rodríguez ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Dose Rate ◽  
Canary Islands ◽  
Absorbed Dose ◽  
Absorbed Dose Rate ◽  
Dose Rates ◽  
La Palma ◽  
Natural Gamma ◽  
Gamma Absorbed Dose ◽  
Cumbre Vieja

<p>The Canary Islands are an archipelago with an area of 7,447 km<sup>2</sup> comprising seven main islands and some islets, located about 90 km off the northwest coast of Africa. La Palma is the most active volcanic island of the Canarian archipelago in historical times (after XV Century), with an area of 706 km<sup>2</sup> and about 83,000 inhabitants. From the geochemical point of view, La Palma is characterized by alkaline rocks ranging from basanites and alkali picrites to phonolites. Despite the different geological units essentially overlap in their bulk chemical compositions, there are significant differences.</p><p>Measurements of natural gamma radiation were carried out in 71 sites randomly selected on a predefined 3x3 km sampling grid covering the whole island in 2013. Total outdoor gamma radiation levels were measured at 1 m above the ground. Air gamma radiation was measured by means of a MINI 6-80 (Mini-Instruments) monitor equipped with an energy-compensated Geiger-Müller MC-71 probe and FH 40 GL 10 (ThermoFischer Scientific) dosimeter equipped with a proportional-gas detector. The background radiation was calculated for each sampling site and subtracted for each dose measurement. Additionally, 25 soil samples were collected at a depth of 0-15 cm in uncultivated fields. Radiometric measurements for <sup>40</sup>K, <sup>226</sup>Ra and <sup>232</sup>Th radioisotopes were performed by low-level gamma spectrometry with coaxial-type germanium detectors (Canberra Industries Inc., USA).</p><p>The gamma absorbed dose rates showed a log-normal distribution, ranging from 37.2 up to 134.0 nGy·h<sup>-1</sup>, with a geometric mean of 64.5 nGy·h<sup>-1</sup>. The observed mean gamma absorbed dose rate in La Palma Island was higher than those measured in La Gomera Island (43.9 nGy·h<sup>-1</sup>), and lower than those measured in Tenerife (89.2 nGy·h<sup>-1</sup>) and El Hierro islands (93.3 nGy·h<sup>-1</sup>) (publication in preparation). The geometric means of <sup>40</sup>K, <sup>226</sup>Ra and <sup>232</sup>Th activity concentration were 216.1 Bq·Kg<sup>-1</sup>, 22.0 Bq·Kg<sup>-1</sup> and 23.6 Bq·Kg<sup>-1</sup>, respectively.</p><p>Maps with the spatial distribution of the terrestrial natural gamma radiation and <sup>40</sup>K, <sup>226</sup>Ra and <sup>232</sup>Th radioisotopes were also prepared and compared with the geochemical composition of soils. Contour maps for the terrestrial radiation component of the absorbed dose rate and radioisotope distributions were obtained using ordinary Kriging interpolation. Lower absorbed dose rates (between 45 and 70 nGy h<sup>-1</sup>) were observed in the oldest northern part of the island, corresponding to the Taburiente and Garafía basaltic shields. Two anomalies were found with absorbed dose rate values between 80 and 110 nGy h<sup>-1</sup>. The first one is located at the Bejenado stratovolcano, extending north to the Caldera de Taburiente, and south to the Aridane Valley. The second anomaly was found in the southeastern part of the Cumbre Vieja ridge. This last volcanic edifice corresponds to the youngest part of the island, where several historical eruptions have occurred. These anomalies might be related to phonotrephritic and phonolitic rocks identified at the upper part of the Bejenado sequence and Cumbre Vieja edifice.</p><p> </p>

CHARACTERIZATION OF SAND SAMPLES FROM KARACHI BEACHES USING GAMMA SPECTROMETRY AND XRD

2020 ◽  
Vol 189 (2) ◽  
pp. 234-241 ◽  
Author(s):  
Jahan Zeb ◽  
Mohammad Wasim ◽  
Sardar A Shah ◽  
Safia Khanam ◽  
Hajira Tahir ◽  
...  
Keyword(s):  
Dose Rate ◽  
Natural Radionuclides ◽  
Absorbed Dose ◽  
Radiation Hazard ◽  
Absorbed Dose Rate ◽  
Radium Equivalent Activity ◽  
Chemical Phase ◽  
Radium Equivalent ◽  
Average Activity

Abstract Chemical phase and distribution of natural radionuclides (226Ra, 232Th and 40K) were determined for sand samples collected from ten different beaches of Karachi. All samples, except one, were identified with major and minor phases as SiO2 and CaCO3, respectively. The average activity concentrations were 24.9, 25.0 and 239 Bq kg−1 for 226Ra, 232Th and 40K, respectively. Including all samples, the average radium equivalent activity was 79.1 Bq kg−1. The external and internal radiation hazard indices and representative level index were all found below unity. The average air absorbed dose rate at 1 m above the sand due to the natural radionuclides was 18.3 nGy h−1, which was less than the world average for soil. The corresponding annual effective dose rate was 22.4 μSv y−1. It was found that Raeq had positive significant correlation with the amount of quartz present at the beaches.

EFFECT OF BUILDUP FACTORS ON INDOOR GAMMA DOSE RATE

2020 ◽  
Vol 190 (2) ◽  
pp. 132-138
Author(s):  
V Manić ◽  
G Manić ◽  
D Nikezić ◽  
D Krstić
Keyword(s):  
Effective Dose ◽  
Dose Rate ◽  
Gamma Rays ◽  
Building Materials ◽  
Absorbed Dose ◽  
Gamma Dose ◽  
Gamma Dose Rate ◽  
Absorbed Dose Rate ◽  
Dose Rates ◽  
Buildup Factors

Abstract The effect of buildup factors on absorbed dose rate in air and the effective dose from gamma rays of primordial radionuclides in building materials, was investigated in the article. Specific absorbed dose rates were calculated for the standard concrete room, as well as, for rooms where brick and covering building materials were used. For all room models the Harima (G-P) buildup factors were applied, while for the standard room the Berger’s and Taylor’s buildup factors were used, too. The contribution of the radiation buildup to absorbed dose rate and effective dose was determined as large as 41%.

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