Natural Radioactivity Levels Research Articles

Determination of the Natural Radioactivity Level of Amasya Şeyhcui Region

People are exposed to both internal and external radiation from the natural radiation sources. For this reason, studies determining the natural radiation level are made to detect the effects of radionuclides, that constitute the natural radiation sources, on the environment and especially the effects of radiation on people and on biological systems. The most common radiation sources are U, Ra, Th and K radioisotopes. In this study, in the samples of the rock and soil acquired from Amasya Seyhcui Region, the activity concentrations of Ra, Th and K are determined by using NaI (Tl) detector with gamma spectrometer and are compared with the limit values.

Estimation and mapping of uranium content of geological units in France

In France, natural radiation accounts for most of the population exposure to ionizing radiation. The Institute for Radiological Protection and Nuclear Safety (IRSN) carries out studies to evaluate the variability of natural radioactivity over the French territory. In this framework, the present study consisted in the evaluation of uranium concentrations in bedrocks. The objective was to provide estimate of uranium content of each geological unit defined in the geological map of France (1:1,000,000). The methodology was based on the interpretation of existing geochemical data (results of whole rock sample analysis) and the knowledge of petrology and lithology of the geological units, which allowed obtaining a first estimate of the uranium content of rocks. Then, this first estimate was improved thanks to some additional information. For example, some particular or regional sedimentary rocks which could present uranium contents higher than those generally observed for these lithologies, were identified. Moreover, databases on mining provided information on the location of uranium and coal/lignite mines and thus indicated the location of particular uranium-rich rocks. The geological units, defined from their boundaries extracted from the geological map of France (1:1,000,000), were finally classified into 5 categories based on their mean uranium content. The map obtained provided useful data for establishing the geogenic radon map of France, but also for mapping countrywide exposure to terrestrial radiation and for the evaluation of background levels of natural radioactivity used for impact assessment of anthropogenic activities.

Study of natural radioactivity in Lake Miri in South West of Sudan

The focus of this study is to investigate the suitability of Lake Miri, a lake with high natural radioactivity in the southwest of Sudan, as a water source for nearby villages. Soil, water, foodstuffs and vegetable samples were collected and analyzed. The results indicate that the mean natural radioactivity level in the study area is 450nGy/h, which is ten times greater than other places in Sudan with normal background (40nGy/h) natural radioactivity, and these findings demonstrate that the average annual exposure of the population is 38.4mSv.

Mineralogy-induced radiological aspects with characterization of commercial granites exploited in Turkey

This study deals with natural radioactivity levels of the ten most important commercial granites from various districts currently being exploited as dimension stone in Turkey. Determining the level of radioactivity is important for human health, particularly for indoor use of granites. This study shows that the relationship between the natural radioactivity and the radiogenic mineralogical contents of the granites exploited for commercial utilization in Turkey is variable. The natural radioactivity levels (i.e., activity concentrations of radionuclides 226Ra, 232Th, and 40K) of granite samples were determined by high-resolution gamma-ray spectrometry. Using these activities, radiological hazard dose rates (absorbed and annual effective) and gamma-activity indexes were calculated using standard equations accepted by public health bodies, taking relevant international reports and guidelines into account. Three of the granites exploited in the Black Sea, Aegean, and Central Anatolia regions were found to be high in radium-equivalent activities and annual effective doses due to minerals bearing the radionuclides, including zircon, apatite, allanite, xenotime, uranothorite, K-feldspars, and biotite. Of those, uranothorite contains large amounts of radionuclides and is present in samples of granites collected from the Black Sea and Aegean regions. Radioactivity measurements using high-resolution gamma-ray spectroscopy serve as a rapid screening tool to evaluate natural radioactivity, whereas detailed petrographic, mineralogical, and elemental investigations can reveal the source of radioactive emissions in granites.

NORM determination in urban soils from selected cities in Chihuahua, Mexico

Soil radioactivity affects the human body. This study determinates the 238 U, 232 Th and 40 K activity (NORM) in 164 urban soils in 13 cities in the State of Chihuahua, Mexico. Absorbed Dose Rate and the Annual Effective Dose were also calculated. Activities were analyzed using a coaxial hyper-pure germanium detector (HPGe), Ge Model 2020, Thermo and Dewar 7500 SL (CANBERRA brand). A one-way variance analysis (ANOVA) was performed and a Tukey test was applied to identify mean differences. Activity averages were 36.8 Bq kg –1 for 238 U, 41.4 Bq kg –1 for 232 Th and 805.7 Bq kg –1 for 40 K. Calculated absorbed dose rate ranged f rom 36 nGy h –1 to 83 nGy h –1 while Annual Effective Dose varied from 1.02 mSv y –1 to 0.44 mSv y –1 . Results suggest that some levels exceed global averages and are among the highest levels of natural radioactivity in the world.

Distribution and environmental impacts of heavy metals and radioactivity in sediment and seawater samples of the Marmara Sea

In this study, the natural and anthropogenic radioactivity levels in the sediment samples collected from the Marmara Sea in Turkey were determined. The average activity concentrations (range) of 226Ra, 238U, 232Th, 40K and 137Cs were found to be 23.8 (13.8–34.2) Bq kg−1, 18.8 (6.4–25.9) Bq kg−1, 23.02 (6.3–31.1) Bq kg−1, 558.6 (378.8–693.6) Bq kg−1 and 9.14 (4.8–16.3) Bq kg−1, respectively. Our results showed that the average activity concentrations of 226Ra, 238U and 232Th in the sediment samples were within the acceptable limits; whereas the average activity concentration of 40K in the sediment samples was higher than the worldwide average concentration. The average radium equivalent activity, the average absorbed dose rate and the average external hazard index were calculated as 100.01 Bq kg−1, 48.32 nGy h−1 and 0.27, respectively. The average gross alpha and beta activity in the seawater samples were found to be 0.042 Bq L−1 and 13.402 Bq L−1, respectively. The gross alpha and beta activity concentrations increased with water depth in the same stations. The average heavy metal concentrations (range) in the sediment samples were 114.6 (21.6–201.7) μg g−1 for Cr, 568.2 (190.8–1625.1) μg g−1 for Mn, 39.3 (4.9–83.4) μg g−1 for Cu, 85.5 (11.0–171.8) μg g−1 for Zn, 32.9 (9.1–73.1) μg g−1 for Pb and 49.1 (6.8–103.0) μg g−1 for Ni. S5 station was heavily polluted by Cr, Cu, Ni and Pb. The results showed that heavy metal enrichment in sediments of the Marmara Sea was widespread.

Technologically elevated natural radioactivity and assessment of dose to workers around a granitic uranium deposit area, China

Gamma dose rates in a uranium site in Guangdong, China were measured based on different functioning areas (mining area, milling area, tailings area and downstream area); four representative soil profiles were measured with HP Ge gamma spectrometry. The gamma dose rates as well as annual effective dose overall exceeded the relevant values reported from other countries. Both the external and the internal hazard index overwhelmingly exceeded the recommended value. Some areas were heavily polluted with technologically elevated concentrations of 238U and 226Ra, while others were observed with extremely high background level of natural radioactivity, mainly stemming from granitic lithology.

Assessment of Human Exposures to Natural Sources of Radiation in Soils of the Cretaceous-Paleocene Formation of Sokoto Basin, Sokoto, Northwestern, Nigeria

Natural radioactivity is a source of continuous exposure to human beings. It originates from both extraterrestrial sources and radioactive elements in the earth’s crust. The amount of radioactivity in soil varies geographically and ggeologically across the world. In Sokoto city and it’s environs, data on the levels of natural radioactivity in soils is absent. It was therefore considered imperative to measure the activity concentration of 226Ra, 232Th, and 40K in soil samples collected from various areas of Sokoto. Activity concentrations were measured by means of Sodium Iodide gamma-ray spectrometry. A total of 12 surface soil samples were collected from around Sokoto city. The measured activity concentrations of these radionuclides were compared with the data reported worldwide. Mean measured activity concentrations of 226Ra, 232Th, and 40K were 53.68.28 Bq kg −1, 115.2928.4 Bq kg −1, and 2003.1278.1 Bq kg−1, respectively. Mean values of radium equivalent activity, air absorbed gamma radiation dose rate, and external radiation hazard index were 378.71±40.19 Bq kg−1, 1.09±0.06 nGy h−1, and 1.006 Bq kg−1, respectively. The annual effective radiation dose was calculated to be 1.09 mSvy−1. The result of this work has established the fact that soils from Sokoto contain enhanced level of gamma radiation that may be hazardous to the inhabitants of the area.

Assessment of the natural radioactivity levels in Kirkuk oil field

The natural radioactivity levels of Kirkuk oil field are studied using high resolution gamma rays spectrometry. For this reason, soil samples were collected from three sites in the Iraq North Oil Company: Baba Gurgur, Shurau and old process plant (Terkiz). The activity concentrations obtained for 238U-series (226Ra, 214Pb, and 214Bi), 232Th-series (228Ac, 212Pb, and 208Tl) and 40K. The results have been compared with the worldwide average values. The radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose rate (AEDE), the external hazard (Hex), the internal hazard (Hin) and Gamma radiation representative level Index (Iγ) were also obtained and compared with the international recommended values.

Assessment of Natural Radioactivity of Soil Sample in Selected Locations of Basrah Governorate

The concentration levels of 226Ra, 232Th and 40K in soil have a great concern in the recent decades, due to its effect on the human health. The radioactivity of some soil samples taken from selected locations in Basrah Governorate have been measured using a NaI(Tl) detector based on gamma ray spectroscopy. Radium equivalent activity, external and internal hazard indices associated with the natural radionuclide were calculated to assess the radiation hazard of the natural radioactivity on the occupiers. The present investigation shows that the level of natural radioactivity for 232Th and 40K in such soil is well below the acceptable limits, while 226Ra is higher. From the analysing the results, it was found that soil in the area does not possess any health hazard to the inhabitant.

Natural Radioactivity Level of Phosphate Fertilizers and Related Products from Al-Qaim Complex Plant in Iraq by Using Solid State Nuclear Track Detector

The natural radioactivity level of phosphate rock, P2O5 (29 - 30 %), TSP, MAP, phosphoric acid, NPK, cryolite, zeolite samples obtained from Al-Qaim Complex Plant in Iraq, as well as organic bitmuse fertilizers were recorded by using solid state nuclear track detector, (SSNTD) CR-39. Three positions were selected for detectors exposure; the upper position that can record the radon originated from uranium; the middle (sample surface), and inside the sample to estimate the total alpha emitter isotopes. The measured values of the radioactivity level were found to be within the range of 113.52 - 1034.29 Bq/m3 and these values belong to Cold (organic bitmuse fertilizers) and MAP-3 (Monoammonium phosphate) samples, respectively. The later was obtained from the treatment process of ~ 60 % phosphoric acid (WPA) with phosphate rock in the Wet process. Generally, the value of the total of radon and thoron radioactivity Ca, roughly indicated by the surface detectors, throughout the chemical process was generally twice the measurement related to uranium at the upper detector. Zeolite sample showed higher radioactivity level than phosphate rock, and this can be considered, as unexpected result for it is not famous ore for uranium scavenging.

Natural and fallout radioactivity levels and radiation hazard evaluation in soil samples

The present study aims to obtain the baseline data on natural and fallout radioactivity and to evaluate radiation hazards caused by ionizing radiation emitted from 226Ra, 232Th, 222Rn, 40K and 137Cs in surface soil samples collected from Mersin province and Akkuyu nuclear power plant region. The activity concentrations of 226Ra, 232Th, 40K and 137Cs were measured using a gamma spectrometer with HPGe detector. The activity concentrations of 226Ra, 232Th, 40K and 137Cs varied from 14.1 ± 0.7 to 65.4 ± 2.9, 12.0 ± 0.8–51.7 ± 2.1, 172.2 ± 15.8–511.1 ± 37.8 and <MDA to 86.2 ± 1.4 Bq kg−1, respectively. The average concentrations of radon in soil and air were estimated as 23.9 kBq m−3 and 76 Bq m−3. The radiological parameters such as absorbed gamma dose rate in outdoor air (DRout), annual effective dose rate from external exposure (EExt), annual effective dose rate from inhalation of radon (EInh) and lifetime cancer risk (LTCR) were calculated to evaluate radiological hazards. The average values of DRout, EExt, EInh and LTCR were found to be 51 nGy h−1, 62 μSv year−1, 715 μSv year−1 and 2.2 × 10−4, respectively.

Calibration with MCNP of NaI detector for the determination of natural radioactivity levels in the field

In view of assessing natural radioactivity with on-site quantitative gamma spectrometry, efficiency calibration of NaI(Tl) detectors is investigated. A calibration based on Monte Carlo simulation of detector response is proposed, to render reliable quantitative analysis practicable in field campaigns. The method is developed with reference to contact geometry, in which measurements are taken placing the NaI(Tl) probe directly against the solid source to be analyzed. The Monte Carlo code used for the simulations was MCNP. Experimental verification of the calibration goodness is obtained by comparison with appropriate standards, as reported. On-site measurements yield a quick quantitative assessment of natural radioactivity levels present (40K, 238U and 232Th). On-site gamma spectrometry can prove particularly useful insofar as it provides information on materials from which samples cannot be taken.

Assessment of natural radioactivity and 137Cs in some coastal areas of the Saudi Arabian gulf

The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for 226Ra, 228Ra (232Th), 4°K and 137Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.

Natural radioactivity levels in soils, rocks and water at a mining concession of Perseus gold mine and surrounding towns in Central Region of Ghana.

Levels of naturally occurring radioactive materials prior to processing of gold ore within and around the new eastern concession area of Perseus Mining (Ghana) Limited were carried out to ascertain the baseline radioactivity levels. The study was based on situ measurements of external gamma dose rate at 1 m above ground level as well as laboratory analysis by direct gamma spectrometry to quantify the radionuclides of interest namely; 238U, 232Th and 40K in soil, rock, ore samples and gross alpha/beta analysis in water samples. The average absorbed dose rate in air at 1 m above sampling point using a radiation survey metre was determined to be 0.08 ± 0.02 μGyh−1 with a corresponding average annual effective dose calculated to be 0.093 ± 0.028 mSv. The average activity concentrations of 238U, 232Th, and 40K in the soil, rock, and ore samples were 65.1 ± 2.2, 71.8 ± 2.2 and 1168.3 Bqkg−1 respectively resulting in an average annual effective dose of 0.91 ± 0.32 mSv. The average Radium equivalent activity value was 257.8 ± 62.4 Bqkg−1 in the range of 136.6–340.2 Bqkg−1. The average values of external and internal indices were 0.7 ± 0.2 and 0.9 ± 0.2 respectively. The average gross alpha and gross beta activity concentrations in the water samples were determined to be 0.0032 ± 0.0024 and 0.0338 ± 0.0083 Bql−1 respectively. The total annual effective dose from the pathways considered for this study (gamma ray from the soil, rock and ore samples as well as doses determined from the gross alpha/beta activity concentration in water samples) was calculated to be 0.918 mSv. The results obtained in this study shows that the radiation levels are within the natural background radiation levels found in literature and compare well with similar studies for other countries and the total annual effective dose is below the ICRP recommended level of 1 mSv for public exposure control.

Comparison between natural radioactivity levels andgeochemistry of some granitoids in western Turkey

Granitoids commonly include K-feldspar, biotite and zircon, apatite, titanite, allanite, and xenotime crystals, which are known to contain common radioactive elements. Radioactive isotopes of 40K, 238U, and 232Th can be harmful to human health with increasing dosage and their quantification should be well defined to assess the suitability of wall-rock granitoids for indoor and outdoor purposes. In this study, it is aimed to correlate the possible relationship between concentrations of natural radionuclides and SiO2, Na2O, K2O, and CaO together with elements U, Th, Zr, Y, Ba, Rb, and Sr to provide a basic approach to the compatibility of geochemical data with natural radioactivity levels of granitic to dioritic rocks in western Turkey. 226Ra, 228Ac, and 40K radioactivity concentrations of the granitoid samples from seven locations range between 15.6 ± 1.5 and 139.7 ± 11.2, 12.0 ± 1.1 and 93.4 ± 9.0, and 297.5 ± 15.5 and 880.2 ± 47.5 Bq/kg, respectively. The lowest 226Ra, 228Ac, and 40K values occur in the Karaburun granitoids while the Buldan granitoids have the highest values. Our data confirm that the silica-rich acidic granitoids have higher natural radioactivity levels than silica-poor basic granitoids and high natural radioactivity levels have been closely associated with high SiO2, Na2O, K2O, Rb, and Ba contents, which may be explained by postmagmatic events of metasomatism and alteration. CaO, Sr, Y, and Zr do not show any correlation with natural radioactivity levels. Natural radioactivity parameters of the studied granitoids are within the safe dosage limits specified in international standards and are safe for use as construction materials. However, metasomatized or strongly altered granitoids may have elevated natural radioactivity levels and hence careful attention is needed for such granitoids.

Natural radioactivity levels of the Egyptian phosphate rocks using BGO detector based portable gamma-ray spectrometer

Gamma-ray surveys are used in geological, geochemical, and environmental mapping for mineral exploration. Natural radioactivity levels for forty phosphate sample localities on the Eastern Desert, Nile Valley, and Western Desert, Egypt, were measured using a gamma-ray spectrometer with high accuracy. From the obtained results, the average values of the annual effective dose were 0.19, 0.28, 0.29, and 0.15 mSv/year for Safaga, Abu.Tartur, El-Sebaeya, and Hamrawayn, respectively. The measured values of natural radionuclides in the studied samples are higher than the world average activity values. This study could be useful as baseline data for radiation exposure to phosphate and their impact on human health.

Determination of natural radioactivity, 222Rn and 220Rn exhalation rates and radiation hazards of fly ash and fly ash brick used in Baotou, China

Natural radioactivity levels, 222Rn and 220Rn exhalation rates and radiation hazards of fly ash and fly ash brick used in Baotou, China were determined. The activity concentrations of 226Ra, 232Th, and 40K in fly ash samples ranged from 38.81 to 93.73, 40.34 to 135.17, and 66.92 to 290.86 Bq/kg with an average of 76.52, 109.95, and 170.72 Bq/kg, respectively; while in fly ash brick samples, these radionuclides ranged from 42.43 to 71.60, 76.65 to 208.37, and 94.32 to 489.42 Bq/kg with an average of 53.83, 101.93, and 266.48 Bq/kg, respectively. The exhalation rates of 222Rn and 220Rn in all determined samples were in the range of 1.13-20.50 and 15.60-113.00 mBq/m2s, respectively. The calculated results of the radium equivalent activity, external hazard index, internal hazard index, indoor annual effective dose and outdoor annual effective dose indicated that fly ashes and fly ash bricks collected from some brick factories of Baotou would pose excessive radiation risks to inhabitants and that they are not suitable for use in building construction. The natural radioactivity level of fly ash and fly ash brick needs to be constantly monitored considering the radiation safety of the local residents.

Natural radioactivity level in materials used for medieval vaulting in the territory of the central Balkan region

This work presents the results of an investigation undertaken to determine the level of natural radioactivity in the traditional building materials used for medieval indoor vaulted constructions in the territory of the central Balkan region. Indoor radiation exposure varies appreciably if it comes from the earth building materials, hence the presence of natural radioisotopes of 226Ra, 232Th, and 40K in masonry vaulted constructions was analyzed using gamma ray spectrometry. In addition, the internal health hazard index, the absorbed dose rates and the effective annual doses were calculated. The results were then compared both with the reported data from the previous studies concerning the territory of the Balkan Peninsula, as well as with the worldwide values for the materials of historic buildings. The results obtained from the materials examined in this paper all showed the radioactivity levels below the maximum permitted values.

Assessment of natural radioactivity levels and identification of minerals in Brahmaputra (Jamuna) river sand and sediment, Bangladesh

Distribution of the natural radionuclides (238 U,232 Th, and 40 K) and their specific activities in sands and sediments of the Brahmaputra (Jamuna) river of Bangladesh together with mineral characteristics has been studied to assess the radiation levels as well as to develop a baseline database for comparison in the future in case of any change in the area under study due to anthropogenic activities. The radiological parameters of natural radioactivity were assessed calculating the radium equivalent activity, hazard index, the absorbed dose rate, and annual effective dose. The average activity concentrations of 226 Ra (238 U),232 Th, and 40 K in sand and sediment were found to be 59 ± 2 & 60 ± 2 Bq/kg, 113 ± 5 & 135 ± 5 Bq/kg, and 983 ± 42 & 1002 ± 43 Bq/kg, respectively. The calculated average absorbed dose rate and annual effective dose were found to be 150 nGy/h and 0.18 mSv/year respectively. These high values are associated with mineral content of the sediment. X-ray diffraction peaks of sand and sediment samples identify quartz, feldspar, rutile, zircon, monazite, uranium fluoride, hematite, kyanite, and uranium arsenide minerals to be present in the samples.