Investigation of natural and artificial radioactivity levels in travertines of the Cappadocia region in Turkey

This study determined natural and artificial radionuclide concentrations to evaluate natural radioactivity and health risk levels of nine travertines in the Yaprakhisar and Balkayası regions in Turkey. The samples coded B1-M, B2, B5, B7, B8, and B10 represent waste derived from the Yaprakhisar travertines, as well as samples T5-M, T12, and Z1 travertines derived from Balkayası. The levels of natural and artificial radionuclide concentrations (232Th, 40K, and 137Cs) were measured using a high-purity germanium (HpGe) detector system. The travertine activity ranged from 2.09 to 12.07 Bq kg-1 for 232Th, 4.21 to 13.41 Bq kg-1 for 40K, and 0.42-3.26 Bq kg-1 for 137Cs. The results showed that the activity concentration values for 232Th, 40K, and 137Cs were coherent with the travertine analysis results in the UNSCEAR, 2000; 2008 publications. The values obtained were lower than the average values in the UNSEAR reports. The radiological hazard parameters calculated in this study were absorbed gamma dose rate (D), radium equivalent activity (Raeq), annual gonadal dose equivalent (AGDE), exposure dose (ER), total annual effective dose (AEDEtotal), excess lifetime cancer risk (ELCRtotal), gamma representative level (GRL), internal hazard index (Hin) and external hazard index (Hex).

Assessment of radiological hazards from radioactivity natural of cement used in Dwellings in Rio de Janeiro, Brazil

Brazil is the fourth largest cement consumer in the world and the largest producer in Latin America, around 1.3% of global production. The main inputs in the manufacture of cement are limestone and clay. Few studies have been carried out in the country on the risk of these materials used in civil construction. Therefore, the objective of this present work is to evaluate the radiological danger that they can present to society. Gamma spectrometry analysis on 16 samples of different brands of cement used as construction material in Rio de Janeiro (Brazil) was performed in this study, using an HPGe detector and the Genie 2000 data acquisition software. Samples were set to count for an accumulation time of 14,400 s (4 h) and all measurements were corrected to eliminate background and backscattering. Activity concentrations are determined for 226Ra was from (41.2 ± 1.6 to 174.9 ± 3.9) Bq kg-1, 232Th was from (15.7 ± 0.5 to 43.1 ± 0.7) Bq kg-1 and 40K was from (82.6 ± 7.2 to 254 ± 17) Bq kg-1. To assess radiological health risks: mean values of Radium Activity Equivalent 150.0 ± 3.4 Bq kg-1, Annual Gonadal Dose Equivalent 468 ± 11 μSv year-1 and Lifetime Excess Cancer Risk (ELCR) 2.42 ± 0.06 were calculated. Total Absorbed Dose Rates ranged from 72.2 ± 1.7 to 225.1 ± 5.2 nGy h-1. The damage to collective health was also estimated from the annual effective dose rates with an estimated total cost of damage to health of US$ 130 million. Values are generally within global limits reported by UNSCEAR.

A pioneering study of the radiological mapping in the world's largest mangrove forest (the Sundarbans) and implications for the public and environment

Coastal Mangroves are facing growing threats due to the harmful consequences of human activities. This first-ever detailed study of natural radioactivity in soil samples collected from seven tourist destinations within the Sundarbans, the world's largest mangrove forest, was conducted using HPGe gamma-ray spectrometry. Although the activity levels of 226Ra (11 ± 1-44 ± 4 Bq/kg) and 232Th (13 ± 1-68 ± 6 Bq/kg) generally align with global averages, the concentration of 40K (250 ± 20-630 ± 55 Bq/kg) was observed to surpass the worldwide average primarily due to factors like salinity intrusion, fertilizer application, agricultural runoff, which suggests the potential existence of potassium-rich mineral resources near the study sites. The assessment of the hazard parameters indicates that the majority of these parameters are within the recommended limits. The soil samples do not pose a significant radiological risk to the nearby population. The results of this study can establish important radiological baseline data before the Rooppur Nuclear Power Plant begins operating in Bangladesh.

Assessment of radioactivity level and associated radiological hazard in riverbed samples within industrial areas

Terrestrial gamma radiation is one of the major outdoor radiation exposures to the general public that varies substantially based on the type and geological properties of the soil. The objective of this study is to evaluate the naturally occurring radioactive materials (NORMs) distribution and assess the hazard parameters in the riverbank soil within various industrial zones in the densely populated Dhaka and Chattogram cities of Bangladesh. The mean activities of 226Ra (37 ± 3), 232Th (58 ± 4), and 40K (1129 ± 18) Bqkg-1 in the assessed soil samples were found to be slightly higher than the world average values 32, 35, and 420 Bqkg-1, respectively. The mean radium equivalent activity (207.49 Bqkg-1) and the external and internal hazard indices were within the recommended limits of 370 Bqkg-1 and <1, respectively. The mean absorbed dose rate (99.47 nGyhr-1), annual effective dose (0.12 mSva-1), ELCR (4.27 × 10-4), and gamma level index (1.58) exceeded the world average values 59 nGyhr-1, 0.07 mSva-1, 2.9 × 10-4, and 1 respectively. However, the studied areas are safe from a radiological viewpoint with no radiation health hazard to the people. The results of this study can be utilized to produce factual baseline data for future studies.

Health risk assessment for soil radioactivity around Shidaowan nuclear power plant in Shandong, China

Monitoring radioactivity levels in the environment around nuclear power plants is of great significance to assessing environmental safety and impact. Shidaowan nuclear power plant is currently undergoing commissioning; however, the baseline soil radioactivity is unknown. The naturally occurring radionuclides 238U, 232Th, 226Ra and 40K, and artificial radionuclide (AR) 137Cs in soil samples around the Shidaowan nuclear power plant were measured to establish the baseline levels. Human health hazard indices such as external hazard indices (Hex), Radium equivalent (Raeq), outdoor absorbed dose rate (Dout), annual effective dose (AED) and excess lifetime cancer risk (ELCR) were estimated. The average concentration of 232Th, 40K, 137Cs, 238U and 226Ra were 42.6 ± 15, 581 ± 131, 0.68 ± 0.38, 40.13 ± 9.07 and 40.8 ± 12.8 Bq per kg, respectively. The average Hex, Raeq, Dout, AED and ELCR were 0.40, 146 Bq per kg, 68.8 nGy per h, 0.09 mSv per y and 3.29E-04, respectively. These data showed an acceptable level of risk to residents near the nuclear power plant and that the current radioactivity in the soil may not pose immediate harm to residents living close to the nuclear power plant. The observed lower AED and 40 K and 137Cs concentrations were comparable to other studies, whilst ELCR was higher than the world average of 2.9E-04. The commissioning of the Shidaowan nuclear power plant is potentially safe for the surrounding residents; further continuous monitoring is recommended.

Assessment of radioactivity in sand samples from eastern Nepal in perspective of radiological hazards

This study was conducted to investigate the activity concentrations of 226Ra, 232Th and 40K in the sand samples and the health hazards associated with them utilizing a NaI (Tl) gamma spectrometer. The average activity concentrations of 226Ra, 232Th and 40K were found to be 24.8 ± 10.1, 39.8 ± 16.4 and 531.3 ± 52.8 Bq kg-1, respectively. The calculated radiological hazard parameters, including radium equivalent activity, absorbed gamma dose and effective dose rate, were found to be 122.7 ± 34.0 Bq kg-1, 57.7 ± 14.9 nGy h-1 and 0.3 ± 0.1 mSv y-1, respectively. Notably, these results were observed to be below the recommended thresholds. Other measured hazard indices were also lower than the prescribed values. From a radiological perspective, the present study concludes that the sand samples do not pose any threat to human health when utilized as a building material.

A preliminary study on determination of radioactivity levels and estimation of the annual effective dose in dried fruits consumed in Albania

This work aimed to support Albania's food safety monitoring regime. In this context, the natural and artificial radioactivity was measured in 20 samples of dried fruits collected randomly in different markets of Tirana. The activity concentration of 40K, 226Ra, 232Th and 137Cs was determined by using the high-purity germanium detector. The maximum values of activity concentration in dried fruits were calculated as 517 ± 22 Bq kg-1 for 40K, 11.10 ± 0.93 Bq kg-1 for 226Ra, 4.38 ± 0.26 Bq kg-1 for 232Th and 0.83 ± 0.14 Bq kg-1 for 137Cs. The average values of activity concentration of 40K and 226Ra were 269and 6.05 Bq kg-1 and the average effective dose to individuals from the intake of the dried fruits was 44 μSv y-1. All average values in this study were lower than recommended values by reports United Nations Scientific Committee on the Effect of Atomic Radiation, World Health Organization and International Commission on Radiological Protection for all age groups. Therefore, all dried fruit samples in this study are safe for consumption with acceptable radiological risk and none of them pose any significant radiological impact. The obtained data in this paper and information for levels of radioactivity and ingestion absorbed dose from dried fruits can be used to be the basic data for future comparative analysis of the other studies.

Assessment of gamma absorbed doses and radiological risk indexes from soil radioactivity around the phosphate area in south Tunisia

Human beings are constantly exposed to the radiations coming from the environment. This work assesses the radiological hazards of natural radioactivity in soil samples taken at four locations around the phosphate area in south Tunisia. Concentrations of primordial radionuclides were measured by gamma spectrometer using an HPGe detector. The overall mean values of 40K, 226Ra and 232Th concentrations were 264, 27 and 13 Bq kg-1, respectively. From the radioactivity measurements, radiation hazard indices specified by the United Nation Scientific Committee on the Effect of Atomic Radiation such as radium equivalent activity (Raeq), absorbed dose rates ($ {\dot{\text D}} $) and annual effective dose (AED) to the population for outdoor environment were determined. The mean values for the abovementioned parameters were 64 Bq kg-1, 33 nGy h-1 and 40 μSv y-1, respectively.

Analysis of internal gamma-ray dose to the public from brick as building material in Tamil Nadu, India

Natural radioactivity due to 238U, 232Th and 40K in brick samples from Tamil Nadu was determined using gamma-ray spectrometry. The mean activity concentrations of 238U, 232Th and 40K, 69 ± 6, 62 ± 6 and 462 ± 23 Bq kg-1, are slightly greater than the world recommended limits of 35, 45 and 420 Bq kg-1, respectively, and they are compared with a similar work carried out across the world. The radiological parameters such as radium equivalent activity, Raeq (193 ± 17 Bq kg-1), internal hazard index, Hin (0.71 ± 0.06), and activity utilisation index, AUI (1.43 ± 0.13), was lower, whilst absorbed dose rate, DRin (89 ± 8 nGy h-1), annual effective dose equivalent, AEDEin (0.43 ± 0.04 mSv y-1), and excess lifetime cancer risk, ELCRin (1.52 ± 0.13 mSv y-1), are slightly greater than the world's recommended limit. Bi-variate statistical analysis was performed to corroborate the relationship between radionuclides and radiological hazards.

Radiation risk assessment of quarry pit soil as construction material in Abeokuta, Nigeria: implications for environmental and public health

ABSTRACTEnvironmental and health risks posed by radionuclides in quarry pit soils are of great concern in environmental health monitoring. The current investigation was aimed at determining the natural radionuclide activity concentration (in Bq kg-1) of the understudied quarry pit granules used as construction materials. The collection and preparation of pit soil samples from Abeokuta quarry sites were done using standard methods, analysis of radiological parameters was carried out using hyperpure germanium (HPGe) spectrometer. Specific activity concentrations of 226Ra, 232Th, and 40K were measured. The values obtained were greater than the world weighted average of 35, 30, and 400 Bq kg-1 for 226Ra, 232Th, and 40K, respectively. The absorbed dose, the annual effective dose, and the radium equivalent were calculated and demonstrated significant values. The radionuclide content of the samples is relatively high and the use of pit soils as a building material, therefore, raises radiological concerns for dwellers in this area and requires periodic monitoring and undergoing a radiation protection program.

Natural radionuclides and radiological risk assessment in the stream and river sediments of a high background natural radiation area Kanyakumari, India

The Kanyakumari coast is known to be a high background natural radiation area due to the placer deposits of heavy minerals such as ilmenite, monazite, and rutile. The Kanyakumari river sediments that could be the source of the elevated amounts of natural radionuclides in the coastal sands have been studied in this paper. The activity concentrations of primordial radionuclides 226Ra, 232Th, and 40K were determined using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 75 Bq kg-1, 565 Bq kg-1, and 360 Bq kg-1, respectively. The mean absorbed dose rate was 395 nGy h-1. Radiological hazard parameters were studied and compared with the world average values. The contribution of 232Th to the total dose rate was found to be higher than that of the two other radionuclides. The high mean ratio of 232Th/226Ra suggested an enrichment of 232Th and the occurrence of 226Ra leaching due to an oxidizing environment. Principal component analysis (PCA) was carried out for the radionuclides in order to discriminate the source of the sediments. This study provides new insights into the distribution of natural radionuclides in sediments of rivers and streams.

Assessment of radioactivity concentration for building materials used in Babadogo Estate, Nairobi City County, Kenya

Natural radioactive materials in certain conditions can get to hazardous radiological level. The aim of the present work was to evaluate the natural activity concentration from sampled building materials collected from different locations in Babadogo Estate within Nairobi City County. The analysis done using gamma ray spectrometer, which was put into action for spectral data acquisition and then analysis. The activity concentration levels of 238U, 232Th and 40K for the selected samples of building materials was measured by the use of gamma ray spectrometry method. The analyzed data compared with the standard acceptable values. The activity concentration in 40K varied from 55 ± 3 to 2647 ± 132 Bq kg-1, giving an average (sum of all values divided by 33) value of 831 ± 42 Bq kg-1; 238U varied from 39 ± 2 to 3602 ± 180 Bq kg-1, giving average figures of 378 ± 19 Bq kg-1 and 232Th ranged from 5.000 ± 0.300 to 4213 ± 211 Bq kg-1, giving average figure of 290 ± 15 Bq kg-1. The calculated average figures for activity concentration surpassed the world average values of 420, 33 and 45 Bq kg-1 in 40K, 238U and 232Th, respectively.

Assessment of NORMs (238U, 232Th, 40K) and radiation hazard indices in Beldih apatite mine region of Purulia district, West Bengal, India

The radiation arising from naturally occurring radioactive materials (NORMs) is the foremost contributor to the collective dose received by the global population. The present study aims to measure the natural background radiation level and the associated gamma radiation dose in air in the Beldih apatite mine region of Purulia district, India. This study is primarily focused on the determination of 238U, 232Th and 40K activities in the sub-surface soil of the study area. The measurements were carried out using a High Purity Germanium (HPGe) detector-based gamma-ray spectrometer with a relative efficiency of 80%. To achieve uniformity in exposure estimations, radium equivalent activity has been calculated. Additionally, the internal hazard index, external hazard index, radioactivity level index and gamma dose rates have been evaluated to estimate the radiation hazard levels in the study area. The comparison of obtained concentrations and hazard indices with global data (UNSCEAR. (2008). Sources, effects and risks of ionizing radiation. United nations scientific committee on the effects of atomic radiation (report to the general assembly, with Annexes).) suggests that this region lies in a relatively high background radiation zone.

Natural Radioactivity of Granitic Rocks and Their Health Risk around Ingesana Mountains, Sudan

ABSTRACT

This work was carried out mainly to analyze radioactive elements 40 K, 232 Th, and 226 Ra and non-radioactive elements in some granitic rocks and study their health risk for humans and non-humans. Radioisotope activity was evaluated using a high-purity germanium (HPGe) detector, and various radiological hazard indices were calculated. We also measured some non-radioactive elements using x-ray fluorescence analysis and performed Pearson correlation analysis to examine the relationships between the radionuclides and the non-radioactive elements. Furthermore, we used the ERICA software to estimate the total dose rate per organism for some non-human biota. The means of 226 Ra, 232 Th, and 40 K are 25.13 ± 5.22 Bq kg -1 , 29.01 ± 6.95 Bq kg -1 , and 323.07 ± 97.83 Bq kg -1 , respectively. Hence, 226 Ra, 232 Th, and 40 K radioactivities were lower than the worldwide average limits. The 226 Ra, 232 Th, and 40 K levels were under the global average values. The hazardous radiometric variables were computed, and the findings observed that the mean absorbed dosage was 23.48 ± 7.36 nGy h -1 , the yearly effective dose rate was 29.82 ± 10.46 μSv y -1 , and the radium equivalent activity was 88.88 ± 18.64 Bq kg -1 . The average dose and yearly effective dose rates were lower than the global average absorbed dose rate of 60 nGy h -1 and the ICRP standard of 1.0 mSv y -1 . The results of Ra-equivalent activity were lower than the recommended maximum criterion for building materials limit of Ra-equivalent activity (370 Bq kg -1 ) proposed by UNSCEAR. Tests of Pearson correlation coefficients indicate a substantial positive relationship between 226 Ra and 232 Th and a modest correlation between 226 Ra and 40 K. Meanwhile, no association between 226 Ra and 40 K and non-radioactive components has been identified. Thorium-232 exhibits a moderately favorable connection with Ti, Fe, and Ni. The estimated total dose rate per organism for the studied non-human is less than the ambient dose rate. However, the total dose rate for small burrowing mammals and reptiles exceeds the background exposure rate. In accordance with the findings, granite rocks may be safe to use as construction materials and pose no threat to human health.

Evaluation of natural radioactivity in soils of Konya (Turkey) and estimation of radiological health hazards

Surface soil samples were collected from Konya, Turkey and natural activity concentrations were determined using the ɤ-ray spectroscopy system with HPGe detector. The activity concentrations of 226Ra, 232Th and 40K were found to vary from 14.07 ± 0.71 Bq kg-1 dw to 67.27 ± 1.62 Bq kg-1 dw, 10.19 ± 2.60 Bq kg-1 dw to 46.09 ± 0.76 Bq kg-1 dw and 107.87 ± 13.32 Bq kg-1 dw to 605.95 ± 11.34 Bq kg-1 dry weight (dw), respectively. The radiological hazard parameters such as Raeq, D, AEDE, ELCR, AGDE, Hex, Hin, and Iɤ evaluated the radiological risk for the public and environment. The mean values of D, AEDE and ELCR are lower than the world average value of 57 nGy h-1, 70 μSv y-1, 0.29 × 10-3 respectively. The activity concentration distribution maps of 226Ra, 232Th and 40K and the radiological maps of the radiological hazard parameters were plotted using the Surfer programme. Cluster analysis was carried out to indicate the similarity between the variables.

Evaluation of soil radioactivity in the areas of underground nuclear explosions at the Pomuk gas field site in Uzbekistan

This study investigates soil radioactivity at the Pomuk gas field in Uzbekistan, a region with history of underground nuclear activity. Using a NaI (Tl) scintillation gamma spectrometer, soil samples were analyzed for concentrations of 232Th, 226Ra, 40K, and 137Cs. Concentrations were found to be in the range of 19.0-31.0 Bq/kg for 232Th, 12.0-32.0 Bq/kg for 226Ra, 450.0-634.0 Bq/kg for 40K, and 2.4-11.0 Bq/kg for 137Cs. Surface radon flux density was measured using a coal sorbent-based passive method, with values ranging from 26.1 to 79.0 mBq/m2s. Mean activity values for radium equivalent (Raeq) and gamma representative level index (Iγ) were calculated to be 75.2-96.5 Bq/kg and 0.3-0.4 Bq/kg, respectively. The absorbed airborne gamma dose rates (GDR) varied between 41.0 and 52.0 nGy/h, while annual effective dose rates (AEDR) were 0.3-0.4 μSv/year. The radiological risk assessment indicates the area is within safe limits for the population and environment, providing a foundation for future radiological monitoring programs.

Distribution of naturally occurring radionuclides and gamma dose rate assessment in the soils of high background natural radiation area Odisha, India

A study on the activity concentration of primordial radionuclides 226Ra, 232Th and 40K was carried out on the surface soil samples collected from the coastal villages between Chhatrapur and Gopalpur regions of high background natural radiation area Odisha, India, using high purity germanium gamma spectroscopy. The mean activity concentrations of 226Ra, 232Th and 40K were found to be 231, 1692 and 250 Bq/kg, respectively. The total mean absorbed dose owing to the presence of 226Ra, 232Th and 40K was 1139 nGy/h. The mean annual effective dose was found to be 1397 μSv/y and higher than the UNSCEAR average value 70 μSv/y.

Assessment of radioactivity levels and radiological hazard indices in phosphate and phosphate mine waste samples from Algeria

Phosphate ore is the starting raw material for production of all phosphate products including fertilisers phosphate waste. It can be of sedimentary, volcanic or biological origin. Like any other geological material found in nature, it contains various amounts of naturally occurring primordial radionuclides, such as 238U series, 232Th series and 40K. Gamma-ray spectrometry was used to assess natural radioactivity levels and radiological hazard indices in phosphate samples. In this paper, the specific activity concentrations of 226Ra, 232Th and 40K of phosphate ores, merchant and mine waste samples were determined. Based on the activity concentrations, the radiation hazard indices (Raeq, Hex, Hin and I𝛾𝑟), and the radiation doses (D, AED and ELCR) were calculated. The results were discussed and compared with those from other studies as well as recommended safety limit values.

Norm in cultivated honey in Malaysia and concomitant effective dose to consumers

Present study concerns the radiological character of Malaysian honey. A total of 18 samples (representative of the various most common types) were obtained from various honey bee farms throughout the country. Using a high-purity germanium γ-ray spectroscopic system, the samples were analysed for the naturally occurring radionuclides 226Ra, 228Ra and 40K. The respective range of activities (in Bq/kg) was: 3.49 ± 0.35 to 4.51 ± 0.39, 0.99 ± 0.37 to 1.74 ± 0.39 and 41.37 ± 3.26 to 105.02 ± 6.91. The estimated associated committed effective doses were derived from prevailing data on national consumption of honey, the annual dose being found low compared with the UNSCEAR reference dose limit of 290 μSv y-1. The estimated threshold consumption rate for honey indicates a maximum intake of 339 g/d, which poses an insignificant radiological risk to public health; however, the total dietary exposure may not, the guidance level of 290 μSv y-1 being applicable to dietary intake of all foodstuffs. The study is in support of the cultivation of a healthy lifestyle, acknowledging prevailing radioactivity within the environment.

Geological control of terrestrial background radiation in Garhwal Himalaya, India

Activity concentrations of 226Ra, 232Th, and 40K were measured in soil samples from several areas of Garhwal Himalaya, Northern India, by gamma-ray spectrometry. In this region, which extends around the Himalayan Main Central Thrust, a tectonic line that separates several geological provinces, background levels of natural terrestrial radiation were assessed. The maximum levels of radium, 285 Bq/kg and 136 Bq/kg, respectively, were found in the Budhakedar and Uttarkashi regions, exceeding the world average value of 35 Bq/kg. The mean radiation levels were found to be different between the areas, which reflects the geological diversity in the region. The overall absorbed dose rate owing to radionuclide presence in the Uttarkashi area ranged from 79 to 188 nGyh-1, with an average of 118 nGyh-1. That is more than UNSCEAR's world-populated weighted average value of 59 nGyh-1. The present investigation indicated that the absorbed dose rates are greater in Uttarkashi and Budhakedar than in other places. The multiple comparison analysis between geology and absorbed dose rate shows that the geology of Uttarkashi and Budhakedar are statistically similar. According to several hazard indices, terrestrial background radiation is not of radiological concern in the investigated region.

Assessment of Radium Equivalent Activity and Total Annual Effective Dose in Cassava cultivated around Ewekoro Cement Factory

In this study, cassava tubers cultivated in the Ewekoro cement area were investigated with the aid of Hyper Pure Germanium (HPGe) detector in order to assess the radionuclide content. Twenty-seven (27) samples of both arable soil and cassava tubers were studied at different sites to the epicenter of the mining activity. The results revealed the highest activity concentrations of K-40, Ra-226, and Th-232 to be 194.10, 63.92, and 76.90 Bq/kg, respectively, in soil to be at site 1, which was 50 m away from the cement mining site. Similarly, cassava reported the highest activity concentrations of 228.15 and 81.50 Bq/kg for K-40 and Ra-226, respectively, at sites 2, which was 150 m away from the mining site. However, the highest value of Th-232 in cassava was noted in site 1. Also, the highest values of Raeq for arable soil and cassava tubers were estimated to be 188.84 Bq/kg and 199.89 Bq/kg at site 1 and site 2, respectively. All the above results were higher than the recommended safe limits by a factor of 2. Moreover, the Total Annual Effective Dose of exposure by oral ingestion of cassava tubers for different age groups revealed children to have the highest level of exposure with the highest mean value of 7.98 mSv. This is followed by adults and infants, which reported 5.66 and 5.38 mSv, respectively, all at site 2. This result is far greater than the recommended safe limits of 1 mSv. Therefore, the results of the total averages of annual effective doses due to consumption of the three natural radionuclides in cassava tubers and other products from it by adults, children, and infants were found to be above the average annual ingestion radiation dose due to natural sources. Further statistical analysis of the results showed significant differences between sites 1 and 2 and between sites 1 and 3, where there was no statistically significant difference between sites 2 and 3.

Measurement of radioactivity in soils of Karamjal and Harbaria mangrove forest of Sundarbans for establishment of radiological database

This work presents the first in-depth study of soil radioactivity in the mangrove forest of Bangladesh part of the Sundarbans. It used HPGe gamma-ray spectrometry to measure the amount of natural radioactivity in soil samples from Karamjal and Harbaria sites of the world's largest mangrove forest. The activity concentrations of most of the 226Ra (14±2 Bqkg-1 to 35±4 Bqkg-1) and 232Th (30±5 Bqkg-1 to 50±9 Bqkg-1) lie within the world average values, but the 40K concentration (370± 44 Bqkg-1 to 660±72 Bqkg-1) was found to have exceeded the world average value. The evaluation of radiological hazard parameters revealed that the outdoor absorbed dose rate (maximum 73.25 nGyh-1) and outdoor annual effective dose (maximum 0.09 mSvy-1) for most samples exceeded the corresponding world average values. The elevated concentration of 40K is mainly due to the salinity intrusion, usage of fertilizers and agricultural runoff, and migration of waste effluents along the riverbanks. Being the pioneering comprehensive research on the Bangladesh side of the Sundarbans, this study forms a baseline radioactivity for the Sundarbans before the commissioning of the Rooppur Nuclear Power Plant in Bangladesh.

Evaluation of radioactivity levels and radiological hazards of some endemic plants used as medicine in Ankara, Turkey

In this study, natural radioactivity levels (226Ra, 232Th, and 4 K) of some medicinal plant samples with known anti-oxidative properties, which are frequently consumed by animals and humans, were obtained from Ankara province and its surroundings (Mamak, Kızılcahamam, Beypazarı, Kahramankazan, and Polatlı districts) were determined using a thallium-doped sodium iodide NaI(Tl) gamma spectrometry. By using the determined natural radioactivity concentrations in the collected plant samples, the number of radiological doses that people could be exposed by consuming these plants was calculated. As a result of the study, 226Ra, 232Th, and 4 K radioactivity concentration ranges of the plant samples were found be 14.69 ± 1.27-59.08 ± 3.12 Bq kg-1, 1.78 ± 0.04-50.05 ± 2.76 Bq kg-1 and 207.24 ± 34.09-826.13 ± 25.40 Bq kg-1, respectively. The highest 226Ra, 232Th, and 4 K activity concentrations were measured in Astragalus densifolius subsp. ayashensis (Kahramankazan), Astragalus kochakii (Kahramankazan) and Rumex patientia (Patience Dock) (Kahramankazan) plants, respectively. The lowest 226Ra, 232Th and,4 K activity concentration plants were determined respectively as Rumex patientia (Mamak), Lavandula angustifolia (Kızılcahamam), and Astragalus acikirensis (Polatlı). The establishment and routine repetition of environmental radioactivity monitoring programs in each region are important for human and animal health, and the results of this study gain importance for Ankara and its surroundings in terms of environmental health.

Dolphin-shaped island: Exploring the natural resources and radiological hazards of Wadi El Gemal Island

The objective of this study is to assess the natural resources and radiological risks of Wadi El Gemal Island by examining its topography, mineralogy, geochemistry, and radioactive distributions. This island, which is situated at the outlet of Wadi El Gemal in Egypt's southeastern Desert, has a unique shape resembling a dolphin based on Landsat imagery. It's a part of the Wadi El Gemal-Hamata Protectorate and is notable for its diverse environmental, geological, economic, and archeological features, including recent reefs, sandy deposits, Quaternary carbonate sediments, and mangroves. The main natural resources on the island are fauna, mangrove forests, and flora. Samples collected from the island were analyzed using a NaI detector to measure the concentrations of radionuclides such as 238U, 232Th, 226Ra, and 40K, which were found to be within acceptable levels according to UNSCAR guidelines. The radionuclide 238U, 232Th, 226Ra, and 40K activity concentrations of the collected samples were 32.55 ± 9, 12.63 ± 4, 12.49 ± 4, and 325 ± 34 Bq/kg, respectively. Regarding radiological hazard indices, the values of absorbed gamma dose rate (36.06 ± 5.42 nGy/h), radium equivalent activity (73.88 ± 14.4 Bq/kg), annual effective dose indoor (0.18 ± 0.03 mSv/y) and outdoor (0.04 ± 0.01 mSv/y), internal (0.29 ± 0.05) and external (0.2 ± 0.03) indices, and excess lifetime cancer index (0.15 ± 0.05 × 10-3).This is suggest that there is no significant risk associated with these sediments.

Evaluation of radioactivity in soil and rock samples from an undiscovered sea beach in the southeastern coastline of Bangladesh and associated health risk

This study marks the first-ever assessment of radiological hazards linked to the sands and rocks of Patuartek Sea Beach, situated along one of the world's longest sea beaches in Cox' Bazar of Bangladesh. Through the utilization of an HPGe detector, a comprehensive analysis of the activity concentrations of 226Ra, 232Th, and 40 K was conducted, and their activity ranged from 7 to 23 Bq/kg, 9-58 Bq/kg, and 172-340 Bq/kg, respectively, in soils, and 19-24 Bq/kg, 27-39 Bq/kg, and 340-410 Bq/kg, respectively, in rocks. Some sand samples exhibited elevated levels of 232Th, while the rock samples displayed higher levels of 40 K compared to the global average. The radiological hazard parameters were assessed, and no values surpassed the recommended limits set by several international organizations. Hence, the sands and rocks of Patuartek sea beach pose no significant radiological risk to the residents or tourists. The findings of this study provide crucial insights for the development of a radiological baseline map in the country, which is important due to the commissioning of the country's first nuclear power plant Rooppur Nuclear Power Plant. The data may also stimulate interest in the rare-earth minerals present in the area, which is important for the electronics industry, thorium-based nuclear fuel cycles.

Car-borne survey and dose assessment from external radiation exposure in Bangka Island

With a history of more than 200 years of tin mining, Bangka Island has brought along a byproduct of heavy minerals containing radionuclide elements. There are some concerns about this byproduct material contributing to natural radiation in the environment. In this study, a car-borne survey was conducted to accurately assess natural background radiation in Bangka Island. Indoor and outdoor ambient dose rates in 146 houses were also measured to assess the radiation dose from external exposure received by the public. Soil samples were collected and measured using a gamma spectroscopy system to evaluate the contributions of specific radionuclides to external terrestrial exposure. From 3790 measurement points during the car-borne survey, the highest ambient dose equivalent rate was 596 nSv h-1 measured in Muntok area, with a mean value of 101 nSv h-1 and a median value of 95 nSv h-1. The ambient dose equivalent rate distribution map showed a relatively higher value in the northern coastal area of the island, where the Pemali tin deposit is located. The annual effective dose received from external radiation in the 146 houses in Bangka Island ranged from 0.44 to 1.30 mSv year-1, with a median value of 0.66 mSv year-1. The soil contained a relatively high amount of thorium (232Th), which contributed 69% to external radiation exposure in Bangka Island.

Measurements of natural radionuclide levels and hazards in the Lega Dembi gold mine, Oromia, Ethiopia

This study aimed to evaluate natural radioactivity levels and hazards of radionuclides 232Th, 226Ra and 40K in soil samples taken from 15 locations in the Lega Dembi gold mining, Oromia, Ethiopia, using gamma-ray spectroscopy coupled with an HPGe detector. It was observed that the respective mean specific activities for 226Ra, 232Th and 40K determined in the mining site were 23.87 ± 0.7, 52.5 ± 1.8 and 391.62 ± 11.35 Bq/kg, and 8.89 ± 0.4, 13.83 ± 0.6 and 423.68 ± 9.5 Bq/kg in the living areas. The specific activity of 232Th was above the permissive limit in the mining site, while for 226Ra and 40K were within the limit. The specific activity of 40K in the living area was observed to be above the permissive limit. The calculated value of radiation hazards parameters; radium equivalent activity (Raeq), internal and external hazards indices (Hin) and (Hex), the mean annual effective dose (AED), and gamma representative indices (Iγ) were within permissively limit. The mean absorbed dose rate in the mining site was above the recommended safety limit. The total annual gonadal dose equivalent value was found to be 494.8 ± 8.7 µSv/a in the mining site. This value was also above the permissively.

Radiogeochemistry, mineralogy, lithology, radiogenic heat production, and health implication using airborne radiometric data of Ilesha and its surroundings

The current study analyzed and interpreted airborne radiometric data from Ilesha's basement complex rock and its surroundings. At the surface, the concentrations of the most frequent primordial radionuclides notably K, elemental concentration of uranium eU, and elemental concentration of thorium eTh were measured. The weighted mean elemental and activity concentrations were 0.85%, 2.75 ppm, 10.22 ppm, and 267.54 Bq kg^-1, 34.41 Bq kg^-1, 41.51 Bq kg^-1 for ⁴⁰ K, ²³⁸U, and ²³²Th, respectively. The low concentration of ⁴⁰ K was certainly due to the effects of weathering, kaolinization of granites, and pedogenesis activities. The abundance of uranium was ascribed to the availability of uranium minerals such as allanite, apatite, and sphene with accessories minerals, while that of thorium was due to minerals such as cheralite, thorite, uranothorite, thorianite, and uranothorianite with accessories minerals. The RPHR weighted mean 1.48 µWm^-3 compared to the earth's crust mean between 0.8 and1.2 µWm^-3 was higher due to significant presence of gneiss rocks in all the studied profiles. Radiological hazard, in particular, dose rates, external hazard index, internal hazard index, radium equivalent, annual gonadal dose, effective dose dispensed to various organs of the body were computed to determine the deleterious effects of rocks in the area. The weighted means of annual gonadal dose of 363.98 µSv y^-1 and outdoor 0.91 × 10^×3 and indoor 1.65 × 10^-3 excessive life cancer risks were more than the global average 300 µSv y^-1, 0.29 × 10^-3 and 1.16 × 10^-3. As a result, proper surveillance is required in the area in order to prevent epidemics occurrence in future.

SEDIMENT RADIOACTIVITY LEVELS DETERMINATION WITH THE HEALTH RISK ASSESSMENTS IN CHEFA RIVER BASIN

The activities of the naturally occurring radionuclides 232Th, 226Ra, 40K and 238U of the shore sediments in the South Gondar Zone were determined and used to evaluate radiation hazards in the study spots. The activities of 232Th, 226Ra, 40K and 238U range from 46 to 179, 62 to 140, 125 to 449 and 72-156 Bq/kg, with the overall average of 123.07 ± 7.90, 105.34 ± 4.27, 371.38 ± 13.53 and 115.52 ± 4.62 Bq/kg, respectively. These were analogous to concentrations of other states in worldwide. We recommend to all the concerned bodies about the environment that the farmers require use the necessary radiation protection method before deploying them for farming (irrigation) activities and preparing for construction. Therefore, accommodating a permanent protection method by talking to the concerning bodies (e.g. Ministry of Agriculture and Ministry of Health) should be taken.

Estimating geothermal and background radiation hotspots from primordial radionuclide concentrations in geology of South Africa

Naturally occurring radionuclides are the main generator of geothermal energy in the Earth's crust and mantle. The generated energy is consequently directly proportional to the concentrations of the three main naturally occurring radionuclides (uranium, thorium and potassium), which are primordial in origin. Concentrations of these naturally occurring radionuclides were extracted for all the different geological rock units in South Africa. The radionuclide concentrations were then mapped and integrated by using QGIS. The results were used to estimate and map the geothermal energy production rates for the rock units. The radionuclide concentrations in the rock units were also used to identify regions with high radiation background. These radiation hotspots were plotted and investigated. The estimated geothermal energy and background radiation hotspots were compared to measurements and projections of other studies and good corelations were found.

Radioactivity amounts, annual effective dose rate, and lifetime cancer risk estimation of some vegetable and fruit samples cultivated in Kahramanmaraş, Turkey

In this research, examples of the fruits and vegetables cultivated in Kahramanmaraş, ²³⁸U, ²³²Th, and ⁴⁰K levels, were detected, and in the case of consumption of these vegetables and fruits, for several age categories (adults, children (10 years old), and infants), annually effective dose rates and lifetime cancer risks were calculated. In fruit samples, concentrations of ²³⁸U, ²³²Th, and ⁴⁰K ranged from under detection limit (UDL) to 15.29 ± 1.14 Bq/kg, 0.30 ± 0.01 to 13.23 ± 1.60 Bq/kg, and 5.82 ± 0.21 to 179.82 ± 1.34 Bq/kg, respectively. The mean concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in fruit samples were 5.31 ± 0.44 Bq/kg, 2.72 ± 0.26 Bq/kg, and 56.84 ± 0.57 Bq/kg, respectively. In vegetable samples, concentrations of ²³⁸U, ²³²Th, and ⁴⁰K ranged from 0.48 ± 0.04 to 11.77 ± 0.95 Bq/kg, 0.55 ± 0.04 to 4.57 ± 0.44 Bq/kg, and 9.32 ± 0.43 to 52.44 ± 0.52 Bq/kg, respectively. The mean concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in the vegetable samples were 6.58 ± 0.65 Bq/kg, 2.72 ± 0.27 Bq/kg, and 27.09 ± 0.27 Bq/kg, respectively. The mean annual effective dose rates for adults, children (10 years old), and infants in fruit samples were 0.184 ± 0.001 mSv/y, 0.288 ± 0.002 mSv/y, and 0.304 ± 0.003 mSv/y, respectively. The average lifetime cancer risks for adults, children (10 years old), and infants in fruit samples were 0.647 ± 0.006 × 10^-4, 1.011 ± 0.010 × 10^-4, and 1.067 ± 0.010 × 10^-4, respectively. The mean annual effective dose rates for adults, children (10 years old), and infants in the vegetable samples were 0.118 ± 0.001 mSv/y, 0.128 ± 0.001 mSv/y, and 0.086 ± 0.001 mSv/y, respectively. The mean lifetime cancer risks for adults, children (10 years old), and infants in vegetable samples were 0.416 ± 0.004 × 10^-4, 0.449 ± 0.004 × 10^-4, and 0.304 ± 0.003 × 10^-4, respectively.

ASSESSMENT OF DOSES FROM INGESTION OF NATURALLY OCCURRING RADIONUCLIDES K-40 AND RA-226 IN RICE CONSUMED IN TAIWAN

This study investigated natural gamma emitting radionuclides 40K and 226Ra in rice consumed in Taiwan. Thirty rice samples, collected from local markets, included 24 local rice and 6 imported rice samples. Radionuclide activities were 24.05 ± 10.21 and 0.62 ± 0.61 Bq/kg for 40Kand 226Ra for all rice samples. The activity of each radionuclide was insignificantly different for local and imported samples (p = 0.33 and 0.52 for 40K and 226Ra, respectively). The annual effective doses from rice consumption were estimated to be 6.80 ± 2.89 and 7.86 ± 7.81 μSv/y for 40K and 226Ra, respectively, and the sum ingestion dose of 226Ra and 40K was 14.66 ± 8.57 μSv/y. These values were one order of magnitude less than the 290 μSv/y world average of the ingestion exposure from natural sources. The results suggest that rice consumption in Taiwan is radiologically safe for the investigated radionuclides.

Radiological and environmental hazards of granitic rocks in Wadi Faliq El Sahl and El Waar area, North Eastern Desert, Egypt

Chronologically, the main exposures in the study area include; tonalite, granodiorite, adamellite, Hammamat Sediments, monzogranite, syenogranite, rapakivi syenogranite, alkali feldspar granite and dykes. This work aims to determine the suitability of the granitic rocks for using as ornamental stones through detecting their radiological and ecological impacts. The studied samples were measured radiometrically by using Na-I detector for determination of ²²⁶Ra, ²³²Th and ⁴⁰K concentrations. External hazard indices (H_ex) in some samples are more than unity, also, the (Raeq) are higher than the exemption limits (370 Bq.kg^-1) exceeds the upper limit of exposure. The hierarchical cluster analysis (HCA) was applied to investigate the correlation between the radionuclides and the corresponding radiological hazard variables. Based on the statistical analysis, ²³²Th and ²²⁶Ra mainly contribute to the radioactive risk of the studied rocks. Regarding ecological indices, 42.1% of younger granite samples have Pollution load index values greater than 1, indicating deterioration, while the majority of older granite samples are lower than 1 suggesting perfection samples. Where, some sample from the older granitoids and younger granites have many radiological and ecological parameters greater than the recommended international limits, so, these samples should not be used in construction for safety reasons.

Study on the Radioactivity Levels of Metal Tailings in the Lhasa Area of Tibet

The main purpose of this study was to determine the natural radioactivity level of raw radionuclides in the metal tailings of a mine in Lhasa, Tibet, and to conduct sampling and detection in 17 typical metal tailing mines in Lhasa, Tibet. The specific activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in the samples were calculated. The total αβχγ radiation, radon concentration, and outdoor absorbed dose rate in the air 1.0 m above the ground were measured. The γ radiation levels affecting miners and their surrounding residents were assessed. The results show that the radiation dose ranges from 0.08 μSv/h to 0.26 μSv/h, and the radon concentration ranges from 10.8 Bq/m³ to 29.6 Bq/m³, which does not exceed the national radiation-related standards, and the environmental hazard risk is low. The specific activity concentration of ²²⁶Ra ranged from 8.91 Bq/kg to 94.61 Bq/kg, the specific activity concentration of ²³²Th ranged from 2.90 Bq/kg to 89.62 Bq/kg, and the specific activity concentration of ⁴⁰K was less than MDA to 762.89 Bq/kg. The average absorbed dose rate (DO) of the 17 mining areas was 39.82 nGy/h, the average annual effective dose rate (EO) was 0.057 mSv/y. The average external risk index of the 17 mining areas was 0.24, the average internal risk index was 0.34, and the average γ index was 0.31, all of which were less than the maximum permissible limit. This means that the metal tailings from all 17 mining areas were within the limit for γ radiation and, therefore, can be used in bulk as major building materials without posing a significant radiation threat to the residents of the study area.

Radiological health assessment of infant milk in Erbil Governorate, Iraq

In this research, the radioactivity caused by natural radionuclides (⁴⁰ K, ²³²Th, and ²²⁶Ra) was evaluated in infant milk consumed in Erbil, Iraq. The measurements were performed using an HPGe gamma-ray spectrometer. The variation of activity concentrations in milk samples was (99.56-256.9 Bq kg^-1) for ⁴⁰ K, (BDL-0.53 Bq kg^-1) for ²³²Th, and (0.27-5.59 Bq kg^-1) for ²²⁶Ra, as determined by the results. The radiological parameters of E_ing, D_org, and ELCR were calculated and compared to international standards. The correlation between computed radiological hazard parameters and natural radionuclides was analyzed statistically using Pearson's correlation. Overall, the results indicate that infant milk consumption in Erbil is radiologically safe and that consumers of these brands of milk are unlikely to be directly exposed to radiological health risks.

RADIOLOGICAL ASSESSMENT OF NATURAL RADIOACTIVITY IN A URANIUM DEPOSIT AREA: KÖPRÜBAŞI, TÜRKIYE

In this study, the results of environmental radioactivity studies conducted in Köprübaşı, Manisa district, where Türkiye's uranium mineral exploration and processing studies were carried out, are shared. Because this is a populated area, there is a need for radio ecological dosimetry assessment to investigate the possible risk to the population. The region where radiological monitoring is carried out is discussed in two parts as the areas where uranium mineral exploration is performed and the settlements close to these areas. It was observed that 714-4714 nGy/h values were obtained in the outdoor absorbed dose rate in air measurements taken in the areas where mineral exploration was performed and this value reached up to 22 857 nGy/h in open field mining areas. In the residential areas, it was recorded that the outdoor absorbed dose rate in air values ranged between 142 and 242 nGy/h and the indoor values ranged between 171 and 400 nGy/h. The world absorbed dose rate in air average values is 57 nGy/h (outdoor) and 75 nGy/h (indoor). The high 226Ra values in the radioactivity analyses of the soil samples draw attention. The mean values of the activity concentrations of the radionuclides 226Ra, 232Th and 40K in the soil samples are 3169, 55 and 802 Bq/kg and the world averages of these values are 35, 30 and 400 Bq/kg, respectively. It was determined that high 226Ra value in the soil in the areas close to the open field uranium mining area was passed on to the agricultural products. Radioactivity measurement results of drinking water samples did not exceed World Health Organization guidelines. According to the radon gas measurement results of 44 houses in Köprübaşı villages, the average radon concentrations in winter, spring, summer and autumn seasons were 72, 61, 50 and 55 Bq/m3, and the annual average value was 60 Bq/m3, respectively. Although these values are greater than the world average of 46 Bq/m3, they are below the recommended limit value (100 Bq/m3). By evaluating the data obtained, the total annual effective equivalent dose values (originating from outdoor-indoor absorbed dose in air, drinking water and indoor radon gas concentration) to which the people in the region are exposed were calculated as a 3.12 mSv.

ASSESSMENT OF GAMMA DOSE AND ANNUAL EFFECTIVE DOSE RATE FOR COMMONLY USED FERTILIZER SAMPLES IN AGRICULTURE FIELD WITH A STATISTICAL APPROACH

In this present study, the activity concentration of the naturally occurring radionuclides 238U, 232Th and 40K have been measured in commonly used chemical fertilizers for agriculture by using gamma-ray spectrometry with NaI (TI) detector. Radiological hazard parameters have been calculated for samples. The mean specific activity concentration of the 238U, 232Th and 40K is 176, 5.75 and 4136 Bq kg-1, respectively. Particularly, the mean value of 238U, as well as 40K, is higher than the world recommended value. Also, the average value of radium equivalent activity is 503 Bq kg-1 and the absorbed dose rate (DR) is 282.93 nGyh-1, which is greater than the permissible limit, whereas the annual effective dose rate (AEDR) is 0.316 mSvy-1, which is lower than the world recommended value. Therefore, collected fertilizer samples significantly increase the activity concentration of natural radionuclides in the agricultural soils. Multivariate statistical techniques such as Pearson correlation and factor analysis are carried out for radioactive variables to understand the existing relationship between them. From obtained results reveals that these fertilizer samples increases the probability of adverse health effects due to natural radioactivity.

Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh

This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of ²³²Th, ²²⁶Ra, and ⁴⁰K were found to be 37.15 ± 3.76 Bqkg^-1, 19.69 ± 2.15 Bqkg^-1, and 347.82 ± 24.50 Bqkg^-1, respectively, where in most cases, ²³²Th exceeded the world average value of 30 Bqkg^-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of ¹³⁷Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of ²³²Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.

RADIOLOGICAL IMPACT OF USING DECORATIVE GRANITE AS AN ATTENUATOR OF IONIZING RADIATION

Granite is a widely available rock, which can be used as a shielding material, for bulk in the form of the aggregate in concrete. It has the weakness that it is more radioactive than many other rocks, which can be used in concrete. This paper looks at its properties as a shielding material and the activity level. Thus, the concentrations of 226Ra, 232Th and 40K, in granite were measured using a high pure germanium detector (HPGe). They were ranged from (15 ± 4 to 49 ± 5) Bq kg-1 for 226Ra, (22 ± 4 to 78 ± 4 Bq kg-1) for 232Th and (791 ± 13 to 1231 ± 15 Bq kg-1) for 40K. Radiological indices of radium equivalent concentration (Raeq), external (Hex), internal (Hin) and annual effective dose were less than worldwide recommended limits. The results emphasized, the granite samples had no radiation hazard. Nevertheless, the mass attenuation coefficients of granite samples were measured for the gamma rays of energy range 122-1408 keV. The mass attenuation coefficients of the studied granite samples were ranged from 0.05 to 0.15 cm2 g-1. In addition, the average the half-value layer of granite was varied from 1.8 cm for 122 keV to 5.2 cm for 1408 keV. The results are that the attenuation characteristics are typical and match the values given by NIST for 'concrete' and that the activity levels of the samples examined are acceptable. Thus the granite may be used as an attenuator for ionizing radiation.

DETERMINATION OF RADIOACTIVITY LEVELS IN BLACK AND WHITE SANDS USED FOR BUILDINGS AND ESTIMATION OF RADIATION HAZARDS IN THE NORTH-WEST REGION OF ETHIOPIA

One hundred and two black and white sand samples were compiled from disparate sand excavates from the affluent rivers of Lake Tana. The supreme values of 226Ra, 232Th and 40K were calculated in Bq Kg-1 units from black sand samples, while the undermost deals were found from pieces of white sand. The potential radiological health parameters were sized up by determining the radium equivalent progressively activity (Raeq), outdoor immersed gamma potion rate (Dout), annual effective potion rate, internal hazard (Hin) and external hazard (Hex) indices and gamma index from using those sands in the erection of dwellings and large buildings. The outcomes acquired show that the annual potion immersed by occupants due to sand construction use in the north-west region of Ethiopia is <1.0 mSv y-1, while the outdoor absorbed dose rate, gamma index and internal hazard index are higher than the quoted values of 55 nG h-1, 1 and 1, respectively.

Seasonal variations of terrestrial gamma dose, natural radionuclides and human health

The aim of the research was to study seasonal variations in gamma radiation and the statistical significance of these variations. Moreover, we compared in-situ and laboratory analyses of uranium, thorium, radium and potassium K-40 contents. Exposure to a low level of radiation is a minor (but still is) contributor to overall cancer risk therefore we compared doses generated by gamma radiation with overall cancer risk. The research was performed in SW Poland in two granitoid massifs -Strzelin and Karkonosze. The in-situ measurements were performed seasonally using gamma-ray spectrometer Exploranium with BGO detector and Radiometer RK-100. The laboratory measurements were performed using spectrometer with HPGe detector Canberra-Packard and alpha spectrometry technique. The general trend of seasonal variations of natural radionuclides, terrestrial ambient gamma dose (TGDR) and ambient gamma dose rate (AGDR) was difficult to identify. We noticed slightly increased values of all analysed parameters in warmer seasons, and lower in colder, although there were some exceptions. These exceptions were induced by precipitation and varied soil water content, but variations were mostly not statistically significant. The statistically important deviation from the trend was registered only in equivalent uranium data when the survey was carried out during or just after intensive precipitation. We observed a good positive correlation between in-situ and laboratory results (TGDR _{in situ/Lab} r = 0.696), therefore, we recommend using in-situ measurements in a dense measuring grid before collecting selected soil samples to better evaluate the level of natural radiation in the environment. The average ambient gamma dose in the Karkonosze Massif was 0.52 mSv y^-1 whereas in the Strzelin Massif was 0.39 mSv y^-1. The overall cancer risk in Karkonoski county is higher than in Strzelin county. A connection between increased gamma radiation and higher overall cancer risk is possible but should be examined during more elaborated research.

Activity concentrations and radiological hazard assessments of 226Ra, 232Th, and 40K in soil samples of oil-producing areas of South Africa

The specific activity of natural radionuclide in soil samples of the oil-producing areas of South Africa was measured using a High Purity Germanium detector. The activity of226Ra, 232Th, and 40K in the soil range from 16.5 ± 1.3 to 64.9 ± 3.1, 16.8 ± 1.5 to 88.6 ± 1.2, 135.2 ± 17.5 to 604.8 ± 13.4 Bqkg-1 for Mossel Bay; 14.3 ± 1.2 to 48.9 ± 8.2, 22.3 ± 1.4 to 45.1 ± 3.2, 237.7 ± 10.9 to 486.5 ± 40.1 Bqkg-1 for Cape Town; 10.5 ± 1.1 to 25.8 ± 3.2, 13.1 ± 1.9 to 44.3 ± 5.2, 140.2 ± 10.9 to 229.8 ± 12.8 Bqkg-1 for Nelson Mandela Bay and 5.6 ± 2.2 to 13.1 ± 2.9, 4.5 ± 2.5 to 14.1 ± 2.7, 62.7 ± 22.6 to 126.5 ± 21.2 Bqkg-1 for Msunduzi. Most soil samples' radiological hazards were within the world average.

Natural radioactivity and radiological risk assessment due to building materials commonly used in Erbil city, Kurdistan region, Iraq

Radiometric monitoring of construction materials is required for estimating the interior and exterior exposure to ionizing radiation emitted by terrestrial radioactive elements in building materials. Using gamma-ray spectroscopy, the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰ K in fifty-two samples from eighteen different building materials commonly used in Erbil city, Kurdistan region, Iraq, were evaluated to assess possible radioactive dangers to human health. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰ K ranged from 1 ± 0.1 (gypsum board) to 130 ± 11 (granite), 1.3 ± 0.2 (gypsum) to 66 ± 8 (ceramic sample), and 18.74 ± 4 (gypsum) to 1061.708 ± 40 (granite) with an average of 28 ± 5, 20.7 ± 4, and 340.8 ± 18 (average ± standard deviation), respectively. Radiological indicators (activity concentration index, alpha and gamma index, hazard indices, interior absorbed gamma dose rate and the corresponding yearly effective dosage rate, and excess lifetime cancer risk) were computed to assess the health risks associated with these building materials. Consideration was given to the indoor annual effective dosage for common construction materials, the radon surface expiration rate, and the indoor radon concentration. The mean values of activity concentration were then inputted into the RESRAD-BUILD computer software to calculate a resident's long-term radiation exposure. The dosages were measured over a range of 0 to 70 years. From 0 to 30 years, there was a significant change in dosages; however, from 30 to 70 years, the dosages were reasonably consistent. This research demonstrates that granite samples are not safe for dwellings with poor ventilation (especially those without windows). In general, other investigated construction materials in the buildings are deemed safe for the population, since the computed values for these parameters fall within the well-being restrictions or criterion values.

Preliminary Screening of Soils Natural Radioactivity and Metal(loid) Content in a Decommissioned Rare Earth Elements Processing Plant, Guangdong, China

Radiological aspects such as natural radioactivity of ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K combined with potentially toxic metal(loid) (PTM) distribution features were seldom simultaneously investigated in rare earth element (REE) processing activities. This work was designed to investigate the distribution levels of natural radioactivity, air-absorbed dose rate of γ radiation as well as PTMs at a typical REE plant in Guangdong, China. Ambient soils around REE processing facilities were sampled, measured and assessed. The natural radioactivity of radionuclides of the samples was determined using a high-purity germanium γ-energy spectrometer while the air-absorbed dose rate of γ radiation was measured at a height of 1 m above the ground using a portable radiometric detector. The PTM content was measured by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the specific activities of the radionuclides ranged from 80.8 to 1990.2, 68.2 to 6935.0, 78.4 to 14,372.4, and 625.4 to 2698.4 Bq·kg^-1 for ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively, representing overwhelmingly higher activity concentrations than worldwide soil average natural radioactivity. The radium equivalent activity and external hazard index of most samples exceeded the limits of 370 Bq·kg^-1 and 1, respectively. The measured air-absorbed dose rate of γ radiation was in a range of 113~4004 nGy·h^-1, with most sites displaying comparatively higher values than that from some other REE-associated industrial sites referenced. The content levels of PTMs of Cu, Ni, Zn, Mn, Pb, Cd, Cr, and As were 0.7~37.2, 1.8~16.9, 20.4~2070.5, 39.4~431.3, 2.3~1411.5, 0.1~0.7, 6.7~526.1, and 59.5~263.8 mg·kg^-1, respectively. It is important to note that the PTM contents in the studied soil samples were 2.1~5.4 times higher for Zn-As and 1.4 times higher for Pb than the third level of the China soil standard while 2.5~13 times higher for Zn-As and 1.2 times higher for Pb than Canadian industry standard. The findings call for subsequent site remediation to secure the ecological environment and human health after the REE processing plant was decommissioned.

The status of natural radioactivity in Nigerian environments

Proper documentation of baseline radiation data of different environments is an important step toward adequate environmental monitoring, and it provides quick means to quantitatively check and determine possible radionuclide contamination by anthropogenic sources. Besides, such documentation is useful for decision making processes, assessment of dose rates to the public, epidemiological studies, and environmental regulations. This review summarizes the results of studies conducted on radioactivity in Nigerian environments. For most soil samples, the levels of radioactivity are well within the world averages of 33, 45, and 420 Bq kg^-1 for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. Other soil samples from regions such as Abeokuta in the southwest, and Jos in the northcentral have been described as high background radiation areas with radioactivity values comparable with those obtained from known high background radiation areas such as the Odisha (formerly Orissa) coast in India (with values reported as 350, 2,825, and 180 Bq kg^-1 for ²³⁸U/²²⁶Ra, ²³²Th, and ⁴⁰K, respectively). In some parts of Nigeria, surface and underground water sources used for drinking and other purposes also present elevated levels of ²²⁶Ra above the world range of 0.01 to 0.1 Bq l^-1 and the tolerable levels recommended by the World Health Organization and U.S. Environmental Protection Agency. Corresponding radiation doses due to measured radioactivities from different environments were estimated and compared with those reported in similar studies around the world. More so, the human and environmental health hazards that might be associated with the reported radioactivity in different environmental settings are discussed. The present report is expected to support authorities in developing appropriate regulations to protect the public from radiation exposure arising from environmental radioactivity. The report also examines other areas of consideration for future studies to ensure adequate radiation monitoring in Nigeria.

STUDIES ON GAMMA DOSE RATES IN OUTDOOR ENVIRONMENT AND ASSESSMENT OF EXTERNAL EXPOSURE TO PUBLIC IN STEPNOGORSK AREA, NORTHERN KAZAKHSTAN

The present study is based on a pilot study, which showed that the Stepnogorsk area of Northern Kazakhstan represents sources of potential contamination of the living environment. The aim of the study was measurement of outdoor gamma radiation levels, activity concentration in soil samples and assessment of external exposure to the public. According to our analysis, the highest ${\boldsymbol{H}}^{\ast}$(10) values ∼2870 nGy h-1 were detected in the Aqsu school territory, which were slightly higher than the control readings for this region. The average 226Ra, 232Th and 40K activities were 617.8 ± 3.2 Bq kg-1, 188.3 ± 2.9 Bq kg-1 and 731.5 ± 6.2 Bq kg-1, respectively. The annual effective dose received by the Aqsu population ranged from 0.08 to 3.5 mSv y-1, which was found higher by an order of magnitude than the upper annual dose limit. Changes in radiation background are an unfavourable factor for the population and may possibly become potential radiation risks for long-term effects.

Gamma-radiation levels outdoors in Great Britain based on K, Th and U geochemical data

Gamma-rays from naturally occurring radionuclides are a major component of background radiation. They are an important tool for geology and are also important for radiation protection. In this paper we use over a quarter of a million geochemical measurements of concentrations of potassium, thorium and uranium in soils and in stream sediments to estimate outdoor gamma-ray dose rates across Great Britain. The soil concentrations are generally at a depth of 5-20 cm with some at 35-50 cm. Soil measurements will give spatially relatively precise estimates, but as soil data are not available for much of Scotland, stream sediment data are used there. Kriging methods are used to estimate surface concentrations of K, Th and U and dose rates are imputed from these concentrations. Our results are compared with measurement surveys of both outdoor and indoor gamma-ray dose rates. Recently there has been interest in exploring the carcinogenic risks of low dose radiation by investigating associations between childhood cancer rates and doses from natural background gamma radiation. To achieve adequate statistical power, such studies must be so large that it is impractical to assess exposures by direct measurements in the homes of study subjects. Instead the exposures must be modelled. The results presented here will be an important input to such work.

RADIOACTIVITY ASSESSMENT OF SURFACE SOIL IN THE VICINITY OF A URANIUM MINE IN MALAWI

The activity concentrations of 238U, 232Th and 40K in the soil of areas surrounding the Kayelekera uranium mine were assessed. This study aims to provide a comprehensive profile of soil radioactivity distribution in the area surrounding the uranium mine to determine radiological hazards associated with mining and processing activities. Soil samples were analysed using gamma-ray spectrometry with a high-purity germanium detector. Mean specific activities of 238U, 232Th and 40K were 58.3 ± 3.7, 40.3 ± 0.3 and 590.9 ± 63.9 Bq kg-1, respectively. Results from this study have indicated changes in radioactivity levels of naturally occurring radioactive materials in the area surrounding the understudied mine, with certain areas close to the mine site showing elevated levels of 238U, highlighting the need for systematic and periodic monitoring.

A Geological Context in Radiation Risk Assessment to the Public

The work aimed to show the applicability of geological studies to the investigation of radiation risk assessment due to the presence of naturally occurring radionuclides of terrestrial origin in the soil. Soil samples were taken from a Tatra Mountains area for which geological maps were available. The concentration of selected radionuclides incl. ⁴⁰K, ²³⁸U and ²³²Th was determined by gamma-ray spectrometry with a HPGe-detector. Radioactivities and calculated absorbed dose rates were co-related to complex bedrock matrices based on an original methodology. The correlations were proved by performing a Principal Component Analysis (PCA). The rocks that had a significant impact on the rate of absorbed dose from the soil were strongly related to the radioactivity of the uranium series. The share of the following fractions was the most significant: granite with pegmatite, gneiss, granitoid and gneiss, coquina, marl and glauconite, hard limestone, dolomite and limestone. The rock types additionally showed good correlation with radioisotopes from the thorium series. Granitoids with potassium feldspar, on the other hand, contributed the largest share of ⁴⁰K radioisotope content.

Assessment of Natural Radioactivity in Cements Used as Building Materials in Poland

It has been analyzed in this article the radioactivity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and radiological hazard parameters in different types of cements commonly used in Poland and available on the Polish market. The radiological hazard parameters are, in particular, absorbed gamma dose rate, annual effective dose, radium equivalent activity, the external hazard index, and the gamma and alpha indices. The radionuclide activities of the most important radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K have been determined by gamma-ray spectrometry with the use of two kinds of spectrometers of different operational parameters. One performed also measurements on 30-day and 45-day aged samples as to verify if there is a statistically significant difference in radioactivity concentration for shorter and longer aging time. The radioactivity concentrations in the cement samples ranged from 21.7-75.7 Bq·kg^-1 for ²²⁶Ra, 12.3-47.3 Bq·kg^-1 for ²³²Th to 123-430 Bq·kg^-1 for ⁴⁰K. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Ra_eq = 127 Bq·kg^-1, mean absorbed gamma dose rate D = 115 nGy·h^-1, mean annual effective dose E = 570 µSv·y^-1, external hazard index H_ex = 0.32, internal hazard index H_in = 0.51, mean activity concentration index I_γ = 0.47 and mean alpha index I_α = 0.28. The results were compared with the reported data from other countries and the international standard values given by European Commission (EC) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR 2000). Finally, thorough statistical analysis has been performed.