DEPTH PROFILING OF RADIOACTIVE NUCLIDES IN SOIL

Analyses of 114 soil samples in Ningbo City show that,in general,there are statistical differences of 137Cs and 40K contents between every layers,the other kinds of natural radionuclides present an increasing tendency with depth.When the γ radiation dose rate is estimated by Beck Formula,owing to the effect of those nonuniform distributions is less than 1% and can be ignored.'

Assessment of Natural Radioactivity in Rivers Sediment and Soil from the Copper Belt Artisanal Mining Region, Democratic Republic of the Congo

The concentrations and distribution of naturally occurring radionuclides (238U, 235U, 234U, 230Th, 226Ra, 210Pb, 232Th, 228Ra, and 40K) were determined by alpha and gamma spectrometry in soil and sediments collected from Luilu and Dilala rivers located in the mining district of Kolwezi (Lualaba Province) of the Democratic Republic of the Congo. The average concentrations of 238U and 226Ra in the analyzed samples were 5 - 10 times higher than the world average values for soil provided by the United Nations Scientific Committee on the Effects of Atomic Radiation. However, the average concentrations of 232Th were found similar to the world average. In both river basins, artisanal mining activities and mineral washing sites displayed the higher concentration values of radionuclides. The mean values of health risk indices calculated for those sites were found significantly higher compared to world average levels. Radiation protection measures seem needed to ensure the radiation safety of local populations. Graphical Abstract

Measurement of Natural Radioactivity and Radon Exhalation Rate in Coal Ash Samples from a Thermal Power Plant

Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that 226Ra activities and 232Th in both ash samples are well above the permissible activity. The values of the external risk index (Hex) and internal one (Hin) for these ashes are below unity, with the exception of 1.28 in fly ash for Hin. The obtained values for the equivalent radium Raeq and annual effective doses Ėin fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq⋅m-2⋅h-1 and 381 mBq⋅m-2⋅h-1, respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn’t have, in any case, a health risk to the public so it can be effectively used in various construction activities.

Assessment of natural radioactivity levels in Yemen rocks

Studies on radiation level and radionuclide distribution in Yemen were studied. The samples were collected from eight locations： Ma＇rib, A1 Jawf, Sana＇a, Dhamar, Amran, Ibb, Al Bayda and Al Dalea. The purpose of this study is to provide a baseline map of radioactivity background levels in the investigated area and this study will be used as reference information to assess any change in the radioactive background level due to geological processes. The highest values of 22~ and 2~l＇h concentrations （8797.2 and 24984.1 Bq.kg＂l, respectively） were observed at A1 Jawf, region, whereas the highest average value of 40K concentration was 1561.9 Bq.kg-1. The investigation of the geological maps of the area under study showed that the surface rock outcrops consist mainly of granites, diorite, granodiorite, gneisses, and schists. All these rock types arc known to be rich in radioactive materials, which are considered natural sources for gamma radiation. The low mdiological background characterizing some Yemeni rocks could be attributed to nature of these rocks which consist of lime stone （sands and gravels）. The absorbed dose rate in air was found to be in the range between 5.40 and 45.11 nGy.h-1 depending on the geological features, and radium equivalent activity concentration was found in the range between 29.57 and 71.85 Bq.kg-1. Also the representative extcmal hazard index values for the corresponding samples were also estinlated and given.

A Study of Chemical, Mineral Compositions (of Some Metals) and Natural Radioactivity in Porcelain and Ceramic Dinner Ware

Fifteen Porcelain and Ceramic Dinner Wares samples (collected from local commercial suppliers—Jeddah Saudi Arabia) were studied applying X-Ray Diffraction and Atomic Absorption techniques were used to study the Chemical, Mineral, Compositions Concentrations (of Some Metals). In addition, the Natural Radioactivity measurements of 226Ra, 232Th and 40K, was used by a high-purity germanium (HPGe) detector. X-ray diffraction results showed that the major mineral constituents of 15 samples were quartz (SiO2) (except one), minor and trace elements vary from sample to sample. Atomic absorption spectroscopy results of the concentrations for (Al, Pb, Bi, U, Th and K) in (ppm) showed that Al2O average was 10.3 (ppm) (10%) less than the acceptable value. PbO, its average was 1.65 ppm which was slightly greater than the allowed value 1.35 ppm. Bi concentrations for all samples were lower than (DL < 10). For most samples U, concentrations were lower than (DL < 5) except samples C9 and C11. Th concentrations ranged from LDL (<1 to 52.88) and were much greater than the acceptable value 7.24 ppm except samples P1, P2, P4. The potassium concentration average was greater than the acceptable value. The average concentrations of 238U, 232Th and 40 K were (83.83, 91.05 and 751.07) Bq/kg dry. The radium equivalent activity concentration Raeq (Bq/kg) (302.61) was less than recommended value (370), gamma dose rate D (nGy/h) average (140.15) was much higher than the recommended value (60) (UNSCEER). Deff (mSv/year) and Hix were below the published admissible limit ≤ 1 and the risk is negligible. This study offers needed information for consumers at exposure risk and is useful to be found in terms of radiation protection.

An assessment of Some Toxic, Essential Elements and Natural Radioactivity, in Most Common Fish Consumed in Jeddah-Saudi Arabia

This study has been carried out to determine the concentrations mg/Kg of the toxic elements (Al, Hg, Cd, Pb, U, Th, and As) and essential elements (K, Sn, Ca, Ni, Cu, Fe, Co, and Mn) using inductively coupled plasma optical emission spectrometer, and the radionuclides concentration levels of (238U, 226Ra, 232Th, 40K and 137Cs) using a high purity germanium spectrophotometer in ten of the most common fish samples collected from local store in Jeddah city, Saudi Arabia during 2014. The results showed that, the concentrations of the elements (Al, Hg, Pb and Cu) in all fish samples were not detected or below the detection limit. The concentrations of metals (Cd, U, Th, As, K, Sn, Ca, Ni, Fe, Co, and Mn) were below the recommended limit by the international organizations. The estimated metal dose (EDI) values for daily average consumption were lower than the recommended values by FAO/WHO, and hazard indices (HI) in fish samples were below safety levels for human consumption (HI 1), then this increase is to be of concern for fish consumer. The measured concentrations in (Bq/Kg) dry weight of natural radionuclides 238U, 226Ra, 232Th, 40K and fallout 137Cs in fish samples were calculated. The results show that the activities in fish samples were of no risk to public health. The total average annual effective dose μSv/y due to intake of 238U, 226Ra, 232Th and 40K from the ingestion of the fish samples were estimated to be 6.07 for infants (≤5 Y), 22.88 and 45.03 for children (5 - 10 Y and 10 - 15 Y) and 56.26 for adults (≥17 y), which are lower than the allowed value (1 mSv). The contribution of 137Cs is nearly negligible. This study could be useful as a baseline data for toxic, essential metals, and radiation, exposure.

Natural Radioactivity Measurements for Some Algerian Building Materials

The objective of this work is to assess the radiation hazards associated gamma rays from building materials. Natural gamma rays activities of natural radionuclide represented mainly by three natural radioactive series ^238U, ^235U and ^232Th, and the primordial ^40K in the samples of building materials which consist of bricks, ceramics, marble and gypsum from different areas of eastern Algeria are measured using gamma ray spectrometry. The values of the activities of these radionuclides do not clearly reflect the radiation hazard associated with these materials. Therefore, the radium equivalent （Raeq） concentration is defined taking into account the effectiveness of these isotopes in creating the radiation hazard. Radium equivalent activities, external and internal hazard indices （Hex and Hin） are calculated from the activities of ^226Ra, ^232Th and ^40K for suitability of the materials.

Evaluation of Natural Radioactivity in Dust Storms Samples from AI-Najaf//Iraq

Abstract： 40K, 238U and 232Th in dust storms samples from AI-Najaf Holy Area - lraq in year 2013 were measured using a high efficiency gamma ray spectroscopy NaI（Tl） detector. From the measured gamma rays spectra, the specific activity were determined for 40K （range from 237.166 to 368.689 Bq/kg）, 23SU （range from 11.531 to 34.997 Bq/kg） and 232Th （range from 2.805 to 11.162 Bq/kg）. Hazard indices （external hazard index, internal hazard index, radium equivalent activities and absorbed effective dose rates） were calculated for the measured samples to assess the radiation hazards arising from dust storms samples, which is the average of Hazard indices equal （0.214, 0.192, 25.359 nG/y and 50.855 Bq/Kg）, respectively. All results of Hazard indices were compared with safe limit values recommended by UNSCEAR （2008） below the safe limit.

Study and Simulated the Natural Radioactivity (NORM) U-238, Th-232 and K-40 of Igneous and Sedimentary Rocks of Al-Atawilah (Al-Baha) in Saudi Arabia

In this work, gamma-ray spectroscopy based on semiconductor hyper pure germanium (HPGe) detector was used to evaluate the activity concentrations of the natural radionuclides (U-238 (Ra-226), Th-232 and K-40) and the fallout nuclide (Cs-137) for thirty samples of igneous and sedimentary rocks of Al-Atawilah (Al-Baha). The mean values of the activity concentrations of U-238 (Ra-226), Th-232, K-40 and Cs-137 in the igneous samples are found as (11.0, 11.50, 1172.71, 1.47) Bq/Kg respectively. In the sedimentary rocks, the mean values of the activity concentrations of the natural radionuclides (U-238 (Ra-226), Th-232 and K-40) and the fallout nuclide (Cs-137) equal to (12.04, 13.18, 1131.36, 1.60) Bq/Kg respectively. The averages of radiological hazards (Raeq, Hex and Iγ) were calculated and found to be within the UNSCEAR permissible limit values (370 Bq/kg for Raeq, and 1 for Hex and Iγ), except for a slight increase of average value of Iγ in the igneous rock samples (1.36). The results indicate that the dose rate values depend on the kind of rocks (high in some igneous rock samples, and most of sedimentary rock samples have low dose rate). The activities of naturalnuclides were predicted and simulated in T time using a written MATLAB R2020a script based on the average activity concentrations and respective half-lives of U-238 and Th-232 series, and K-40, this is to evaluate the future effects of natural radionuclides on the population and estimate the human inputs in the future.

Determination of Natural Radioactivity of the <i>Hibiscus sabdariffa</i>Linn (Roselle) Used in Côte d’Ivoire (Ivory Coast)

In this work, ten medicinal and nutritional leaves samples of Hibiscus sabdariffa Linn imported from Mali and Burkina Faso in Côte d’Ivoire and sold on the market were collected. The analysis of these plants using High Purity Germanium detector (HPGE) gamma spectrometry showed the activity concentrations of 226Ra, 232Th, and 40K varied respectively in the range of (1.74 - 0.11) × 10−3 Bq/kg, (6.72 - 0.61) × 10−4 Bq/kg and (4.65 - 0.54) × 10−3 Bq/kg1 in the leaves of H. sabdariffa. The Average Annual Committed Effective Dose (AACED) values from leaves this plant varied from 251.492 × 10−6 to 68.133 × 10−6 mSv/y. These values found are below 0.30 mSv/y, the world average value for an individual. These results show that there is no radiological risk in consuming “bissap” leaves.

Determination of Natural Radioactivity in Different Regions of Iran and Compared with Global Standards

Soils are naturally radioactive, because of their mineral content. An effective dose delivered by photon emitted from natural radioactivity in soil （40K, 23SU and 232Th and their progenies） was calculated in this work. Calculations were performed using the ORNL （Oak Ridge national laboratory） human phantom and Monte Carlo N-particle transport code MCNP-4C according to ICRPI03 recommendations. Optimum dimensions of each source were determined considering the incident photon energy. Then, these dimensions were employed in the MCNP code input for calculation of conversion factors which relate the effective dose rate and activity. The obtained factors of the 238U series, 232Th series and the 4~K in soil are 0.383, 0.314 and 0.019 nSv h-~ per Bq kg~, respectively. These results were compared with other studies and revealed that there is a good agreement exists between two sets of data. The estimation of the effective dose rates and the annual effective dose for the adult population has been derived in different regions of Iran, considering the natural radioactivity distribution in soil samples from these regions. Finally, the obtained results in this study were compared with UNSCEAR （United Nations Scientific Committee on the Effects of Atomic Radiation） 2008 report.

Total Indicative Dose Determination in Water from the North Riviera Well Field of SODECI in Abidjan, Cote d’Ivoire

The Uranium-238 (238U), Thorium-232 (232Th) families and Potassium-40 (40K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of 238U, 232Th and 40K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides238U, 232Th, and 40K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.

Determination of gross α and β activities in Zouma River based on online HPGe gamma measurement system

This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in natural water are provided by natural and artificial radionuclides such as ^(40) K,^(137)Cs,and radionuclides belonging to ^(238)U and ^(232)Th series.The main a emitters related to gamma emissions in natural water are ^(224)Ra(240.98 keV)and ^(226)Ra(186.21 keV),and the β^(-) emitters are ^(40) K(1460.85 keV),^(214)Bi(609.31 keV),^(208)Tl(583.19 keV),and ^(214)Pb(351.93 keV).The formula for gross α and β^(-) activity concentration is based on these radionuclides,and the short half-life decay products are considered in the calculation.The detection efficiency of the device across energy region(0–3 MeV)is obtained through Monte Carlo simulation,and a calibration experiment is conducted to verify the simulation results.Gamma radioactivity is measured continuously for 114 d in Pixian County and Dongfeng Canal located in the Zouma River,Chengdu,Sichuan Province,China.A comparison of the calculation results and monitoring data from the Sichuan Management and Monitoring Center Station of Radioactive Environment indicates that the percentage and absolute error of a activity concentration is lower than 53%and 0.02 Bq/L,respectively,and that of β-activity concentration is lower than 33.2%and 0.016 Bq/L,respectively.The method can rapidly determine gross α and β^(-) activity concentrations in natural water online.

Fertility Cancer and Hereditary Risks in Soil Sample of Nasarawa, Nasarawa State, Nigeria

A survey of Fertility Cancer and Hereditary Risks in Soil Sample of Nasarawa was carried out.This study assessed the level of Fertility Cancer and Hereditary Risks from the naturally occurring radionuclides;^(232)Th,^(226)Ra and ^(40)K.12 soil samples collected from the respective part of the Nasarawa were analyzed using the gamma-ray spectrometry NaI(Tl)detector system.The mean concentration for ^(40)K was 645.29±07.32 Bq/kg,for ^(226)Ra was 28.43±4.8422 Bq/Kg and for ^(232)Th was 66.84±2.0201 Bq/Kg.The average effective dose due to the ingestion was 0.36±0.1μSv/y which was approximately 1000 times lower than the world average effective dose.Radium equivalent activity Ra_(eq)(Bq/kg),alpha index and total cancer risk were found to be 161.44±8.08 Bq/kg,0.142±0.02 and(0.21±0.05)×10^(-5) respectively.UNSCEAR/USEPA stipulated that;radium equivalent activity,alpha index,effective dose and total cancer risk should not exceed the limit of 370 Bq/kg,unity,300μSv/y and 1×10^(-4) respectively.Hence the values obtained in this work were within the acceptable limits.This implies that the ingestion or inhalation of soil is not associated with any radiological risk of concern.

Radiological Effectual and Mineral Salts Measurements of Sandstone Used in the Construction from Al Wajh, Al Ula and North Al Ula, Az Zabirah-Saudi Arabia

The activity concentrations of natural radionuclides 226Ra, 232Th and 40K, were measured in (16) sandstone samples collected from two regions of Saudi Arabia, Region 1 (Al Wajh on Red Sea coast and Al Ula north-East of Medina), Region 2 (North of Al Ula and Az Zabirah, North-West of Hail) by (HPGe gamma spectrometer). The activity concentration average values of the radionuclides 226Ra, 232Th, and 40K in the sandstone samples (Region 1) ranged from 10.97 ± 0.43, 27.68 ± 0.37 and 64.56 ± 0.74 Bq/kg respectively. These values are less than the international values reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000), in (Region 2), average values ranged from 2465.49 ± 0.00, 2042.00 ± 0.00 and 2259.65 ± 0.64 Bq/kg respectively. These values are higher than the values reported by (UNSCEAR, 2000). Average values of radium equivalent activity Raeq (Bq/Kg), absorbed dose rate D (nGy/h), annual effective radiation dose Deff (mSv/y), External index (Hex) and Internal index (Hin) were in (region 1) 21.13, 27.22, 11.75, 0.07 and 0.10 respectively, in (region 2) 5775.19, 1787.78, 846.58, 11.57 and 15.64 respectively. These results are lower (except annual effective radiation dose) in (region 1) and higher in (region 2) than the world recommended values by (UNSCEAR, 2000). Also, samples were analyzed by Atomic Absorption spectrometer (AAS) for Al, Ca, Fe, K, Mg and Bi in % elements concentrations. Average value in (region 1) (Al Wajh and Al Ula) are 4.42, 0.41, 1.37, 0.04 and 0.03, (in region 2) (N. Al Ula and Az Zabirah) are 12.50, 10.05, 1.01, 1.19, 0.04 respectively. Classifications of sandstone depend on the content of these elements. These results are important for the safety of dwellers and user of sandstone in constructions.

Investigation on 226Ra, 238Th, 4040K and 137Cs Concentrations in Common Polishing Materials Consumed by Inhabitants in Saudi Arabia

Knowledge of radioactivity present in polishing materials enables one to assess any possible radiological risks to human health. In this work, the radioactivity due to the presence of 226Ra, 232Th, 40K, and 37Cs has been measured in polishing materials con-sumed in Saudi Arabia using gamma spectrometry with HPGe. The activity concentra-tions of 226Ra, 232Th, 40K and 137Cs ranged from 13.61 ± 0.005 to 0.60 ± 0.002, 18.43 ± 0.003 to 0.78 ± 0.001, 342.59 ± 0.009 to 2.47 ± 0.001 and 1.47 ± 0.001 to 0.55 ± 0.001 Bq/l, respectively. For 226Ra and 40K, the highest values are measured in stainless steel polisher. The highest values also measured in metal polisher (copper-chrome) and disinfectant cleaner and polisher sample for 232Th and 137Cs. Radium equivalent activ-ity due to the natural radioactivity of the investigated samples ranged from 51.37 to 1.24 Bq/l. This value is less than the recommended values in the established standards. The evaluated data were compared with the literature data. Our results indicate that no significant radiological hazards arise from using investigated samples hence quite safe to be used as polishing materials.

Evaluation of natural radioactivity and radiological hazards in basement rocks from Gabel Abu El-Hassan in the North Eastern Desert of Egypt by multivariate statistical approach with remote sensing data

Purpose The present work deals with the natural radioactivity levels of basement rocks from Gabel Abu El-Hassan in the North Eastern Desert of Egypt.Methods The activity concentrations of 226Ra,232Th and 40K in rock samples were measured using a gamma-ray spectrometry with an HPGe detector.Landsat Enhanced Thematic Mapper Plus(ETM+)data were processed and interpreted to create rock forming radioactive map.Results and conclusion The activity concentrations of 226Ra,232Th and 40K varied from 28.2±9.4 to 259.6±38.6 Bq/kg,37.9±9.9 to 297.4±54.6 Bq/kg and 487.0±73.4 to 5514.6±786.0 Bq/kg,respectively.The radiological hazard indices(gamma index),the annual effective dose rate and excess life-time cancer risk were estimated to assess the radiological hazards due to the use of rock samples as building material.Remote sensing data were also used to integrate between radioactive analysis and Landsat-7(ETM+)data processing to detect radioactive anomalies and to identify the uraniferous alteration zones in Abu El-Hassan area.

Simulation of natural radioactivity backgrounds in the JUNO central detector

The Jiangmen Underground Neutrino Observatory（JUNO） is an experiment proposed to determine the neutrino mass hierarchy and probe the fundamental properties of neutrino oscillation.The JUNO central detector is a spherical liquid scintillator detector with 20 kton fiducial mass.It is required to achieve a 3%/√E（MeV） energy resolution with very low radioactive background,which is a big challenge to the detector design.In order to ensure the detector performance can meet the physics requirements,reliable detector simulation is necessary to provide useful information for the detector design.A simulation study of natural radioactivity backgrounds in the JUNO central detector has been performed to guide the detector design and set requirements for the radio-purity of the detector materials.The accidental background induced by natural radioactivity in the JUNO central detector is 1.1/day.The result is satisfied for the experiment.