Average Activity Concentrations Of 40K Research Articles

Assessment of Natural Radioactivity and Associated Radiological Indicators in Water and Surface Soils Around Beta Glass Plc and Its Environs, Ughelli, Delta State, Nigeria

A radiometric assessment was conducted around Beta Glass plc using sodium iodide detector (3×3-inch NaI (TI)). The study collected 14 soil and 13 water samples from June to July 2022, analyzing radioactivity concentrations of 40K, 238U, and 232Th. The mean specific activity concentrations of 40K, 238U, and 232Th were 184.00±29.73 Bqkg-1, 14.55±2.50 Bqkg-1, and 8.60±1.04 Bqkg-1, respectively, in soil samples, but these elements' concentrations in water were 27.429±5.633 BqL-1, 6.661±1.421 BqL-1, and 2.518±0.361 BqL-1, respectively. The average activity concentrations of 40K, 238U, and 232Th were lower than the safe limit, and the corresponding radiation hazard indices for soil samples were all below the UNSCEAR-recommended acceptable limits. The mean activity concentrations of radionuclides in water samples were higher than the UNSCEAR's recommended international limits for 40K, 238U, and 232Th. Nonetheless, elevated radiological health hazards imply that cumulative dosages may cause cancer, even though these values might not pose an immediate health concern to the local community's people or the workforce.

Radiological hazards assessment of building materials used in Swakopmund, Namibia

A Canberra coaxial High Purity Germanium (HPGe) gamma-ray spectrometry detector was used to measure activity concentrations of radionuclides in commonly used building materials in Swakopmund, Namibia. The activity concentrations in, Bq.kg−1, for 226Ra, 232Th and 40K in all sample groups of building materials (cement, sand, cement bricks and roof tiles) were found to be in the range of 18.002–499.266, 14.069–132.508 and 162.794–1747.260, respectively. The average activity concentration of 40K was found to be two times higher than the critical level of 500 Bq.kg−1 in sand, cement bricks, clay bricks and roof tiles. The measured activity concentrations were used to estimate average dose rates and radiological hazard parameters. The absorbed dose rate (D) both due to indoor and outdoor exposure was higher than the international acceptable safe limits in all sample groups while the annual effective dose equivalent (AEDE) due to indoor exposure was higher in sand, cement bricks and clay brick samples. AEDE due to outdoor exposure was within acceptable safe limits for all sample groups. Radium equivalent (Raeq), external hazard (Hex) and gamma (Iγ) hazard indices were found to be higher than the acceptable safe limit only in clay bricks samples. The internal hazard (Hin) index was only higher than the acceptable safe limit in cement and clay bricks while the alpha (Iα) index was higher in sand, cement bricks and clay bricks. The Excess Lifetime Cancer Risk (ELCR) exceeded the acceptable safe limits in all sample groups. Our study showed that most of the computed radiological parameters were significantly higher than prescribed safe limits in most of the samples and therefore may pose a health risk to the inhabitants of Swakopmund.

Naturally occurring radioactive materials (NORM) concentration and health risk assessment of aerosols dust in Nicosia, North Cyprus

This study was carried out to evaluate the distribution of naturally occurring radioactive materials (NORM) and radiological risk indexes in aerosol dust in Nicosia, Cyprus utilizing a high-resolution HPGe gamma-spectrometry. The activity concentrations of 226Ra, 232Th, and 40K in the selected aerosol dust samples ranged from 25.9–52.4, 21.7–46.3, to 471–1302 Bq kg−1, respectively. The average activity concentrations of 40K were found to be above the Earth's crust average. The internal and external hazard indexes are well below the acceptable limit in most dust samples. All investigated samples met the exemption dose limit of 0.3 mSv y−1.

Estimation of Radiation Dose in Building Materials Used In Federal University Gusau Using Gamma-Ray Spectroscopy Analysis

This study estimated the radiation dose in building materials (sand, cement, and granite) in Federal University Gusau, Zamfara State, Nigeria, through gamma-ray spectrometry system using a Sodium Iodide Thallium activated "NaITl" detector in a low background configuration. The range of the average activity concentration of 226Ra was found to be 56.65±0.75Bqkg-1 to 159.45±2.68Bqkg-1, which was higher than that of the world mean value for soil 35Bqkg-1,for 232Th the range was 46.65±0.45Bqkg-1 to 79.32±1.68Bqkg-1, all the samples, were found to be higher than that of the world mean for soil 30Bqkg-1. While the activity concentrations of 232Th levels of blocks, granite, and sand samples are all above the world range, except the cement which was within the worldwide range 194.84±1.31Bqkg-1 to 656.84±0.76Bqkg-1. The average activity concentration of 40K for cement, sand, and blocks was within the worldwide range, with granite samples slightly higher than the world mean value for soil 400Bqkg-1. The results have been compared with the world mean values of 35, 30, and 400Bqkg-1 specified by the UNSCEAR (2016). Concerning radiological risk to human health, the absorbed gamma dose rate (D) was estimated to be above the world average range of 55nGyh-1; the outdoor annual effective dose equivalent (AEDE) were, estimated to be below the permissible limit of 0.07mSvy-1. The values of Raeq, Hex, and Hin for all the samples in the present work are lower than the accepted safety limit value of 370Bqkg-1 and below the limit of unity, respectively.

Ingestion exposure of public to natural radionuclides and committed effective dose and cancer risk through tuber crops cultivated in Ebonyi State, Nigeria.

Internal exposure of public to radiation arising from ingestion of natural radionuclides in tuber crops of Ebonyi State origin was investigated in this study. Committed effective doses and lifetime cancer risk of 40K, 226Ra, and 232Th in cassava, cocoyam, water yam, and white yam were calculated. The average activity concentrations of 40K, 226Ra, and 232Th determined by gamma spectrometric Na (TI) detector were, respectively, 199.15 ± 23.51, 77.57 ± 7.98, and 118.20 ± 10.72 Bq/kg in cassava; 146.62 ± 40.69, 43.42 ± 7.63, and 75.61 ± 2.89 Bq/kg in cocoyam; 162.81 ± 20.43, 63.17 ± 11.36, and 81.50 ± 10.27 Bq/kg in water yam; and 184.50 ± 20.22, 80.23 ± 10.93, and 116.29 ± 5.93 Bq/kg in white yam. The total committed effective dose via ingestion aligned in this orderof cassava (7.05 mSv/year) > white yam (4.38 mSv/year) > water yam (0.42 mSv/year) > cocoyam (0.21 mSv/year) with overall average dose of 3.12 mSv/year. The values of dose were higher than world average of 0.29 mSv/year given by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The lifetime cancer risk values were above tolerance level of >10-4 prescribed by United States Environmental Protection Agency (USEPA), suggesting probable evolvement of radiogenic cancer morbidity. The data presented in this study contributes to baseline information on radiological characteristics of tuber crops in Ebonyi, which would be valuable to WHO/FAO food safety policy in Nigeria and rest of the world.

Measurement of Radionuclides and their Impact on the Environment Around Asphalt Plants in Delta State

Measurement of radionuclides and their impact on the environment around asphalt plants in some selected Asphalt mixing plant within Delta State, Nigeria was carried out. The Background Ionizing Radiation and the GPS of the location was measured using a well calibrated Gamma scout; Geiger counter multi-radiation meter and a GARMIN GPS meter and the result obtained at Raycon, DLA and Neodede Hot Asphalt Mixing Plants for outdoor exposure, shows a total mean value of (0.01492±0.038) (mRh-1), (0.01497±0.037) (mRh-1) and (0.01413±0.014) (mRh-1) respectively. The total mean values obtained in the selected radiological centers were all above the world average BIR level of 0.013 (mR?-1) as recommended by UNSCEAR (2000). These results were used to calculate some hazard indices such as the Equivalent dose (ED) in mSv??1, the absorbed dose rate (ADR) in nGy??1, Annual Effective Dose Equivalent (AEDE) and Excess Life Cancer Risk (ELCR). All the values obtained for each Parameter were above the world permissible limits as given by UNSCEAR (2000). The average activity concentration of 40K, 238U and 232Th in the soil of the three study areas were (603.21±30.94) Bq/Kg, (5.70 ±0.678) Bq/Kg and (6.91 ± 0.405) Bq/Kg. For 40K the average activity concentration was high and above the world recommended limit of 420 Bq/Kg (UNSCEAR 2000). 238U and 232Th were below the world recommended limits which are 33 Bq/Kg and 45 Bq/Kg. respectively. The Activity Concentration results were used to calculate the following radiological parameters: Absorbed gamma dose rate (DR) in (nGy/h), Annual Effective Dose Equivalent AEDE in (?Svy-1), the Radium Equivalent (Raeq), Excess Life Cancer Risk (ELCR) and External Hazard Index. All the calculated radiological Values were above the recommended limit given by (UNSCEAR 2000). Water samples in the study areas was also collected and the average activi

Radioactivity of anthropogenic and natural radionuclides in marine sediments of the Chaun Bay, East Siberian Sea

Natural radioactive isotopes serve as a useful proxy of geological and geochemical processes in marine environment, while radiocesium serves as an indicator of man-made contamination. Monitoring of natural and anthropogenic radioactivity under conditions of the climate changes in the Arctic region is of high importance in investigations of this natural system. For the first time, we report the data on spatial distribution of natural (232Th, 226Ra, 40K) and anthropogenic (137Cs) radionuclide activities in the marine sediments from Chaun Bay (East Siberian Sea). The measured activity concentrations varied in the range 23.7–77.9 (mean 39.2) Bq kg−1 for 232Th, 16.5–39.3 (mean 26.6) Bq kg−1 for 226Ra, 535–991 (mean 726) Bq kg−1 for 40K, and 0.5–4.7 (mean 2.0) Bq kg−1 for 137Cs. The radiocesium level in the sediments showed no local sources of anthropogenic pollution in the Chaun Bay, while the average activity concentration of 40K was 1.8 times higher than worldwide.

Assessment of natural radionuclides in powder milk imported to Erbil Governorate, Kurdistan Region-Iraq

In this study, the activity concentrations of 40K, 232Th, and 226Ra radionuclides were estimated in imported milk powder samples from 40 brands available in local markets in Erbil Governorate, Iraq. The measurements were performed using High Purity Germanium (HPGe) detector. The results indicated that the average activity concentrations of 40K, 232Th, and 226Ra were 241, 0.476, and 1.23 Bq kg−1, respectively, and comparisons were made based on the typical consumption characteristics of powdered milk by Kurdistan residents. In all investigated age groups (2–17 years), the average annual effective doses were below the ICRP-recommended limit of 1 mSv y−1 for public exposure. Radiological hazard parameters were determined based on the measured radioactivity concentrations. The relation between all the determined activities of natural radionuclides and radiological parameters was examined using multivariate statistical analysis techniques such as histograms, descriptive statistics, and Pearson correlation analyses. The cancer risk in all samples was lower than the allowable value of (2.5 × 10−3), while the ingestion dose in two samples was higher than the worldwide acceptable value of (0.29) mSv y−1.

Radionuclide contents in sediment and seafood from Makoko Lagoon, Lagos State, Nigeria

Sediment and seafood samples were collected from Makoko Lagoon, Lagos state, Nigeria. Gamma-ray spectrometry was used to determine the activity concentrations of 40K, 226Ra and 232Th in the samples. The average activity concentrations of 40K, 226Ra and 232Th in the sediment were 41.04 ± 6.41, 10.15 ± 3.19 and 4.39 ± 2.10 Bq kg−1, respectively, while the annual effective dose was 0.01 mSv/year. In seafood, the average activity concentrations of 40K, 226Ra and 232Th were 15.66 ± 8.07, 1.72 ± 1.51 and 1.93 ± 0.30 Bq kg−1, respectively. The cumulative effective ingestion dose obtained ranged from 0.016 μSv/year (giant prawn) to 1.08 μSv/year (Parrotgrunt). The mean activity concentrations and absorbed dose rate in sediment were below the worldwide average values. The cumulative dose from the ingestion of seafood was also significantly low. Sediment and seafood from the lagoon in Makoko pose no health risk from a radiological point of view to the population.

Activity concentrations and radiological hazard assessments of 226Ra, 232Th, 40K, and 137Cs in soil samples obtained from the Dongnam Institute of Radiological & Medical Science, Korea

The radioactivity concentration of environmental radionuclides was analyzed for soil and sand at eight locations within a radius of 255 m centered on the Dongnam Institute of Radiological & Medical Science (DIRAMS), Korea. The average activity concentrations of 40K, 137Cs, 226Ra, and 232Th were 661.1 Bq/kg-dry, 0.9 Bq/kg-dry, 21.9 Bq/kg-dry, and 11.1 Bq/kg-dry, respectively. The activity of 40K and 137Cs was lower than the 3-year (2017–2019) average reported by the Korea Institute of Nuclear Safety, respectively. Due to the nature of granite-rich soil, the radioactivity of 40K was 0.6-fold higher than in other countries, while 137Cs was in the normal fluctuation range (15–30 Bq/kg-dry) of the concentration of radioactive fallout from nuclear tests. The activity of 226Ra and 232Th was lower than in Korean soils reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average activity concentrations of 232Th and 40K for the soil and sand samples from DIRAMS were within the range specified by UNSCEAR in 2000. The radium equivalent activity and internal and external hazard index values were below the recommended limits (1 mSv/y). These radionuclide concentration (226Ra, 232Th, 40K, and 137Cs) data can be used for regional environmental monitoring and ecological impact assessments of nuclear power plant accidents.

The occurrence of 40K and 137Cs radioactivity in mosses during 2015-2019 in the Djerdap National Park (E. Serbia).

The radiation status of the national park (NP) Djerdap (Eastern Serbia) is characterized using bioindicators (mosses). Mosses (16 species, 156 samples) were collected randomly within the area of NP Djerdap during the month of June, periodically from 2015 to 2019. Samples were collected in the regions of Dobra, Donji Milanovac, and Tekija. Within the mosses, the presence of 40K and 137Cs is regarded as a good indicator of radionuclides present in the environment due to their easy interchangeability with 39K highly present in living moss organisms. The activity concentrations of gamma ray-emmiting radionuclides in samples were determined using high-resolution gamma ray spectrometry, an HPGe-ORTEC/Ametek detector. The determining activity concentrations of 40K and 137Cs in collected samples were as follows: for 40K from 31.4 to 721Bqkg-1and for 137Cs varied from 2.6 to 908Bqkg-1. The average activity concentrations of 40K and 137Cs (Bq kg-1) in mosses in the period 2015-2019 were the lowest in moss samples collected in the Dobra region, and the highest in the area of Donji Milanovac. The most prevalent collected moss species within the Djerdap National Park was Hypnum cupressiforme. The determined activity concentrations in H. cupressiforme of 137Cs for the whole region of NP Djerdap for all 5years was 78.1 ± 70.3Bqkg-1 and of 40K was 181 ± 86.1Bqkg-1.

Assessment of naturally occurred radiation hazards in chemical and organic fertilizers used in Chattogram area, Bangladesh

ABSTRACT The present work deals with identifying and determining the activity levels of naturally occurring radionuclides 226Ra and 232Th series, their decay products and 40K in chemical and organic fertilisers used in the Chattogram area, Bangladesh. A total of 39 samples collected from retail markets were investigated, out of which 28 are chemical fertilisers and the others are organic fertilisers. The average activity concentration of 226Ra and 232Th found in TSP fertiliser are 304.57 ± 36.0 and 19.1 ± 6.8 Bq kg−1 respectively and the average activity concentration of 40K in MOP fertiliser is found as 10,311.11 ± 1168 Bq kg−1. In the organic fertiliser samples, the mean concentration of 226Ra, 232Th and 40K are 17.35 ± 3.11, 7.20 ± 1.74 and 437.14 ± 42.58 Bq kg−1, respectively. The mean absorbed dose rates were measured after the end of our experiment, and the value was found to be 91.39 nGy h−1. The combined (indoor + outdoor) annual effective dose equivalent was also estimated as 0.322 mSv year−1. The mean radium equivalent activity found to be 190.15 ± 26.74 Bq kg−1 is well below the recommended level of 370 Bq kg1. The internal hazard index, external hazard index, and radioactivity level index of the investigated fertiliser samples were found as 0.56 ± 0.034, 0.54 ± 0.08 and 0.69 ± 0.10, respectively. From the calculated hazard parameters, the excess lifetime cancer risk (ELCR) was found to be higher than the world average in most of the chemical fertilisers except in DAP and BOR, while the organic fertilisers show lower than the world average. The obtained results reveal that there are no significant radiation hazards due to natural radionuclides of the fertiliser samples in the studied area, but the higher concentration of 40K in MOP suggests strengthening the regulatory work. Overall, this study highly recommends the use of organic fertilisers, as these kinds have hazard parameters lower than the recommended levels.

Soil to tobacco component transfer factors for natural radionuclides 40K, 226Ra, and 232Th and the risk assessment of tobacco leaf in smoking

This study determined the activity concentrations and corresponding transfer factors (TF) of 40K, 226Ra, and 232Th in three tobacco components (root, stem, and leaf). The radiation hazard index parameters were assessed for the tobacco leaf. The activity concentrations in the soil were 589–762, 32–43, and 49–59 Bq kg-dw−1 (dry weight) for 40K, 226Ra, and 232Th, respectively. The average activity concentrations of 40K, 226Ra, and 232Th were 447, 5.41 and 5.69 Bq/kg-dw for the root, 670, 9.64 and 7.61 Bq kg-dw−1 for the stem, and 793, 6.79 and 6.15 Bq kg-dw−1 for the leaf, respectively. The TF values were 0.42–1.42, 0.10–0.49 and 0.06–0.23 for 40K, 226Ra, and 232Th, respectively. The stem and leaf 40K TF values were significantly higher than the root values. The stem 226Ra TF values were significantly higher than the root values. The 226Ra and 232Th activity concentrations and TFs of tobacco components had a significant positive correlation. Based on the activity concentrations of the tobacco leaves, the annual inhalation effective dose to the lungs for an adult smoker was 0.32–0.81 mSv y−1 (average 0.60 mSv y−1). The Excess Lifetime Cancer Risk (ELCR) caused by smoking was an average of 2.39 × 10−3.

CHARACTERIZATION OF RADIOACTIVITY FROM PRIMORDIAL RADIONUCLIDES IN THE SOIL OF IKA SOUTH LOCAL GOVERNMENT AREA OF DELTA STATE

This study presents the characterization of the soil in Ika South Local Government Area of Delta State. It presents radiometric (40K, 238U and 232Th) survey of soil samples collected from some selected towns in Ika South Local Government Area of Delta State, Nigeria using gamma-ray [NaI(TI)] spectroscopy.Twenty five representative soil samples from five communities (five soil samples each per community) were collected for the study. The average activity concentration of 40K, 238U and 232Th in soil samples from the selected communities was 510.87 ± 3.068 Bqkg-1, 31.092±2.638 Bqkg-1 and 64.662 ± 2.842 Bqkg-1 respectively. By comparing the obtained average result of soil samples of 40K, 238U and 232Th with UNSCEAR standard, it was observed that the obtained average results of 40K and 232Th exceeded the standard value limit of 400 Bqkg-1 and 30 Bqkg-1 respectively while 238U was less than the standard value limit of 35 Bq/kg-1. The calculated radiological hazard values were lower than the world allowable average standard, except for the annual gonadal dose equivalent and the excess lifetime cancer risk which were above than the world recommended average standard value of 300 mSv/yr and 0.29 x10-3Sv/yr standard in some communities. However, contactwith the soils in these communities will not pose much health hazard problem to man and the environment

Radiogeochemistry, uranium migration, and radiogenic heat of the granite gneisses in parts of the southwestern Basement Complex of Nigeria

The radiogeochemistry of granite gneisses in Akunu-Akoko (AK) and Ayere (AY) areas of the southwestern Basement Complex of Nigeria was studied using gamma-ray spectrometry, and geostatistical analysis and modeling. This study was aimed at determining the concentrations of radionuclides (K, U, and Th) in these rocks, as well as alteration scenarios, nature and rates of uranium migration (UM), levels of radiological hazards, and rate of radiogenic heat production (RHP). The interquartile (lowest Q1 < highest Q2 < highest Q3) elemental concentrations for 40K, 238U, and 232Th were 0.23 < 3.75<4.06%; 1.00 < 4.20<5.40 ppm; and 4.10 < 16.10<30.20 ppm, respectively, within the minimum and maximum limits of BDL (below detection limit) to 5.23%, BDL–9.70 ppm, and 0.40–60.20 ppm. The average activity concentrations of 40K, 238U, and 232Th with values of 629.28, 38.58, and 49.96 Bqkg−1, respectively, were above their crustal averages in the order of AK3<AK2<AK3<AY3<AY1<AY2. Variability in K-eU-eTh content and alteration in the rocks were affirmed by radioelement ratios and F-parameter. The high radionuclide concentrations may be attributed to high levels of radioactive materials, as well as trace and rare earth elements. Low radionuclide concentration in rocks is due to weathering, metamorphism, and 12–86% outward UM. The absorbed dose rate (ADR) average of 75.09 nGyh−1 was within the allowable range, with regression R-squared (R2) prediction values of 25–92% from the radionuclides. The average radium activity was below the permissible limit of 370 Bqkg−1, and the annual effective doses, hazard indices, gamma activity, and activity utilization index were all far below the safe limit of 1 mSvy−1. However, gonad equivalent and excess lifetime cancer risk were above their permissible limits. RHP average of 1.89 μWm−3 above the crustal range of 0.8–1.2 μWm−3 will considerably contribute to the heat flux in the areas. Based on the prediction accuracy of the R2 results, 36–86% of RHP rates in the rocks are achievable from the radionuclides.

Investigation of the Radiological Risk of Farmlands and the Transfer Factor from Soil to Crops in Jalingo and Wukari L.G.A of Taraba State, Nigeria

The activity concentrations of radionuclides, absorbed dose rate, excess lifetime cancer risk, and soil-to-plant transfer factor have been evaluated in soil and crop samples from Jalingo and Wukari Local Government Area of Taraba State, Nigeria. The activity concentrations were determined with the aid of High Purity Germanium detector. The absorbed dose and excess lifetime cancer risk were evaluated and forecasted for 60 years using the ResRad off-site model. The average activity concentration of 40K, 232Th, and 238U in the soil samples were 633.13, 141.15, and 71.20 Bq·kg-1 respectively, for the Jalingo study area, and while that of the Wukari study area was; 199.21, 87.23, and 25.37 Bq·kg-1 respectively. The average soil-to-plant transfer factors for 40K, 232Th, and 238U were 0.51, 0.10, and 0.27 respectively for the Jalingo study area while that of Wukari are 0.40, 0.57, and 0.74 respectively. The mean annual effective dose equivalent for the study area is higher than the world average of 0.07 mS·vy-1. The excess lifetime cancer risk for the study areas has values that are higher than the safety limit. The ResRed model showed that direct radiation from the crops is the major contributor to excess cancer risk among other pathways. The radiological hazard indices reveal health risks to farmers, especially in the Jalingo area.

Distribution of some natural and anthropogenic radionuclides in the sediments and seawater along the coastal areas of North Sulawesi

Studies on the radionuclide distribution of some naturally occurring radioactive materials (NORM) and anthropogenic radionuclides in the sediments of the coastal areas of North Sulawesi were conducted to provide baseline data for the effective monitoring of radioactive fallout in these areas. Sediment samples were collected by a van Veen grab samples about 100 – 300 m from the shoreline, and 60 L of seawater was pre-concentration to precipitated 137Cs. Activity concentration of the three main natural radionuclides (222Ra, 232Th, and 40K) and 137Cs were determined using a high-resolution HPGe gamma-spectroscopy system and presenting background about the radiological levels and assessing the associated hazards. The activity of 226Ra ranged from 2.1 to 9.5 Bq kg−1 with an average value of 5.9 Bq kg−1. The activity of 232Th varies from 2.4 to 10.4 Bq kg−1 with an average value of 5.2 Bq kg−1. The 40K ranges between 169.1 to 492.7 Bq kg−1 with an average value of 238.8 Bq kg−1. The average activity concentration of 40K (238.8 Bq kg−1) in the sediment samples was lower than the worldwide average concentration (420 Bq kg−1). The current level of activity 137Cs varied from 0.05 to 0.40 Bq kg−1 in sediment samples and 0.98 to 1.33 Bq m−3 in seawater samples. 134Cs in all samples were not detected or below the detection limit. This fact indicated that radioactive cesium in Celebes Sea areas of North Sulawesi still originated from global fallout and insignificant influenced by the FDNPP accident. All radionuclide radiation values in the recent study are lower than the world average. Therefore, the potential danger of radiation generated from the surrounding environment has not yet caused a radiological health impact for the people living on the coast of North Sulawesi. Natural and artificial radionuclide activity data in this study will be used as the basis for sedimentary activity along the coast of North Sulawesi.

Activity concentrations of 226^Ra, 232^Th, and 40^K in common maize meal consumed in Namibia and their potential radiation hazards

Gamma spectroscopy was performed to determine the concentrations of 40K, 226Ra and 232Th in maize meal samples collected from shop outlets and open markets in Namibia. The activity concentrations and Excess Lifetime Cancer Risk were determined using a high purity germanium (HPGe) detector. The average activity concentrations of 40K, 226Ra and 232Th were found to be 29.98 ± 4.05, 0.99 ± 0.40 and 0.35 ± 0.08 Bq.kg – 1 in the maize meal samples. The result showed the activity concentrations of 40K significantly higher than the other radionuclides in all the maize meal samples. The average excess life cancer risk varies from 1.33 x 10 – 13 to 6.05 x 10 – 13 for 40K, 8.76 x 10 -13 to 1.19 x 10 – 12 for 232Th and 2.43 x 10 -11 to 2.83 x 10 – 11 for 226Ra. Hence, when compared with internationally acceptable limits, all values fall within the safety limits. Thus, the study concludes that the maize meals consumed in Namibia are radiologically safe for consumption.

Natural radioactivity and total K content in wild-growing or cultivated edible mushrooms and soils from Galicia (NW, Spain).

The radioactive isotope, 40K, of naturally occurring potassium (0.012%) is present in the Earth's crust in a low percentage of all potassium, leading to its presence in almost all foodstuffs. The impact of 40K activity concentrations was assessed in wild and cultivated edible mushrooms and in growing substrates. Samples were analysed by gamma spectroscopy. In the wild mushroom species, the average activity concentration of 40K was 1291 Bq kg-1 dry weight (dw), approximately 140 Bq kg-1 fresh weight (fw), with a range of average values per species from 748 in Lactarius deliciosus to 1848 Bq kg-1 dw in Tricholoma portentosum. The cultivated species presented an average value of 1086 Bq kg-1 dw; and the soils, compost of cultivation and wood of substrate are 876, 510 and 59.4 Bq kg-1 dw, respectively. The total K content reached a maximum of 59,935 mg kg-1 dw in T. portentosum. The transfer factors (TF > 1) suggested that mushrooms preferentially bioconcentrated 40K. Cantharellus cibarius, Craterellus tubaeformis, Hydnum repandum and T. portentosum by most TF could be considered as bioindicators of 40K. Taking into account that the annual radiation dose of 40K due to the average consumption of mushrooms analysed (0.15 μSv/year) is very low, it can be concluded that the consumption of these mushrooms does not represent a toxicological risk for human health. Finally, according to the total K content, from the nutritional point of view, these mushrooms could be considered as a potential source of potassium for the human diet.

Investigation of natural radionuclide and essential metal contents of ancient wheat einkorn (Triticum monococcum L.) grown in Turkey

Abstract Einkorn (Triticum monococcum L.) is accepted as the oldest known wheat. In this study, the natural radionuclide and essential metal contents of siyez samples collected from 21 different cultivation areas in Kastamonu province located in the Western Black Sea region of Turkey were determined by using non-destructive analytical methods. The average activity concentrations of 40K, 226Ra and 232Th measured in siyez samples using a gamma-ray spectrometry were found as 181.3 ± 4.1, 10.0 ± 0.7 and 6.1 ± 0.2 Bq kg−1, respectively. The average annual effective radiation dose that the people are exposed to due to the consumption of siyez samples was estimated as 68.2 ± 3.1 µSv y−1. The average concentrations of Cr, Mn, Fe, Co, Ni, Cu and Zn essential trace metals analyzed in einkorn samples using EDXRF spectrometry were found as 3.6 ± 0.2, 89.2 ± 1.2, 208.5 ± 62.6, 16.8 ± 0.6, 12.1 ± 0.1, 8.3 ± 0.2 and 65.3 ± 2.5 mg kg−1, respectively.