RADIOECOLOGICAL IMPACT AND THE ASSOCIATED HAZARDS DUE TO NORM FROM OIL AND GAS PRODUCTION FACILITY IN THE WESTERN DESERT OF EGYPT

An oil and gas production facility in the western desert of Egypt was investigated for possible radiation risks due to the routine operation. Radium-226, Radium-228 and Potassium-40 were assessed in the soil samples collected from the adjacent soakaway pond. The average 226Ra, 228Ra and 40K activity concentrations were 881.0 ± 42.0, 966.0 ± 43.0 and 143.0 ± 8.0 Bq kg-1, respectively. Both 226Ra and 228Ra were above the world ranges, while 40K was within the world range. Water samples from the facilities effluent's produced water showed elevated levels of both radium isotopes. The effective doses at three different points on the separator outer surfaces over the period between 1995 and 2014 were assessed. The maximum reading was 5.4 μSv h-1 on 2014. The time has significantly contributed to the enhancement of the effective dose readings. However, they are still within the expected range encountered in similar studies reported by International Atomic Energy Agency (IAEA).

DOSE ASSESSMENT OF NATURAL TERRESTRIAL RADIONUCLIDES IN COMMONLY CONSUMED FOODS IN NORTH INDIA

The present study aimed to record natural radionuclide content in branded food samples representative of a typical North Indian diet. Forty samples of various food items falling into three categories namely, cereal grains, pulses and beverages were collected from the local markets of Punjab. The radiometric analysis was performed using NaI(Tl) scintillator detector. The activity concentrations ranged between 10 ± 1 and 20 ± 5 Bq kg-1 for 226Ra, Below Detectable Limit (BDL) and 10 ± 2 Bq kg-1 for 232Th and 440 ± 56 and 562 ± 70 Bq kg-1 for 40K. The radium equivalent (Raeq) varied from 55 Bq kg-1(corn) to 70 Bq kg-1 (tea) with an average of 62 Bq kg-1. Internal hazard index (HI) was also calculated (0.18-0.24), which was well below the prescribed threshold of one (24). Age-specific annual effective doses were estimated for infants, children and adults. Children were the most sensitive group of population to radionuclide doses from cereal grains. The annual effective doses were further used to calculate the lifetime cancer risk which exceeded the world average of 2.9$\times$10-4 (24). However, the overall results showed that the intake of these dietary products by the general public did not pose any serious health risk.

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

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

RADIOMETRIC SURVEY OF THE TYAA RIVER SAND MINE IN KITUI, KENYA

Gamma spectroscopic analyses of sand and rock samples from Tyaa River report an average activity concentration of 33 ± 1, 55 ± 2.8 and 812 ± 40.46 Bqkg-1 for 226Ra, 232Th and 40K, respectively in the sand. A similar analysis of rock samples reveals a mean of 21 ± 2.47, 49 ± 2.47 and 782 ± 39.13 Bqkg-1 for 226Ra, 232Th and 40K, respectively. The absorbed dose rate in rocks averaged 75 ± 3.78 nGyh-1, while in the sand was 86.2 ± 4.31 nGyh-1. The ranges and mean radiological hazard indices (radium equivalent, internal and external) were within the permissible limits and the use of sand and rocks from this mine as construction material pose no health risks. Correlation analysis between the radioactivity in the sand and rocks reveals weak non-linear positive relationships suggesting that they might be from different bedrocks.

ASSESSMENT OF NATURAL RADIOACTIVITY LEVELS AND RADIOLOGICAL HAZARDS IN BUILDING MATERIALS

Radioactivity of 226Ra, 232Th, and 40K were measured in a total of 92 samples, including eight commonly used types of building materials that were obtained from local manufacturers and suppliers in Beijing. Concentrations were determined using high-purity germanium gamma-ray spectrometry. The 226Ra, 232Th, and 40K activity concentrations in all samples varied from 10.1 to 661, 3.3 to 555 and 3.2 to 2945 Bq per kg with an average of 127.8, 114.8, and 701.5 Bq per kg, respectively. The potential radiological hazards were estimated by calculating the absorbed dose rate (D), radium equivalent activity (Raeq), external hazard (Hex), and internal hazard (Hin) indices. The investigated building materials were classified into different types according to the radioactivity levels. Results from this research will provide a reference for the acquisition, sales, and use of building materials. Attention should be paid to the use of coal cinder brick, ceramic, and granite in the construction of dwellings.

Age-dependent effective ingestion dose estimations and lifetime risk assessment for selected radionuclides (40K and 3H) in bottled waters marketed in United Arab Emirates

Monitoring drinking water, including bottled water, is imperative to safeguarding public health especially where bottled water consumption is high like in the United Arab Emirates (UAE). In this study, radionuclide activity levels of Tritium (³H) and Potassium (⁴⁰K) were assessed in various brands of bottled water marketed in UAE. Activity level data was used to calculate the annual effective doses (E_d) for different age groups, and the excess lifetime cancer risk (ELCR) for adult males and females in the UAE population. Activity levels for both radionuclides were below the allowable maximum guideline values specified by local and international standards. Calculated total age dependent ingestion doses revealed that adults and lactation age groups received the highest effective ingestion doses. Adult males exhibited a higher ELCR for both isotopes, compared to females. Nonetheless, total radioactive dose for each water brand (0.91-1.47 μSv/yr) as well as for each population group were well below the recommended annual reference dose level of 100 μSv set by World Health Organization. Therefore, bottled water in the UAE is safe from the radiological aspect for investigated radionuclides, and poses no significant radiological exposure and health risk to the public.

Estimation of absorbed gamma dose rate from granite by Monte Carlo simulation approach

Apart from the continuous exposure of humans to background ionising radiation, an increased level of radiation may also originate from the use of building materials with an enhanced level of radioactivity. Thus, it is necessary to examine the content of radionuclides present in building materials, as well as the corresponding dose which may be received by residents from these materials. In this paper, particular attention was dedicated to finding the absorbed dose rate and annual effective dose caused by the presence of naturally occurring radioisotopes ²²⁶Ra, ²³²Th, and ⁴⁰K in granite, a widely used building material, by means of Monte Carlo simulations. In addition, the obtained dose rate simulation results were compared with values estimated from commonly used simple equations, relating to the dose rate emitted by granite plates, covering the interior of a standard room. In the simulation, a room was constructed with standard dimensions (4 m × 5 m × 2.8 m), and with floor and walls covered with 3 cm thick granite. A water cylinder (approximate mass 65 kg) was positioned in the center of the room, representing a human body. The emission of the most intense gamma rays from ²²⁶Ra and ²³²Th progenies, as well as from ⁴⁰K, emanating from the granite matrix, was simulated. The number of generated photons in each simulation (typically it was an order of magnitude of ~10⁶) precisely represented actual activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in granite samples. All processes playing a role in the interactions of gamma photons with the granite matrix itself, the outer concrete shell, the air within the room, and the water cylinder, were taken into account by GEANT4 simulation software, after which the spectra of deposited energy inside of the water cylinder were obtained. Based on the deposited energy, the absorbed dose rate and annual effective dose were calculated for 6 analysed granite samples, each with different ²²⁶Ra, ²³²Th, and ⁴⁰K contents. Furthermore, the effect of the position of the water cylinder in the simulated room on the absorbed dose rate was considered, as well as the distribution of the deposited energy within the water cylinder. The absorbed dose rates, and consequently annual effective dose, obtained in the simulations were found to be 30%-40% higher than the values obtained from using a standard formula.

Artificial (137Cs) and natural (40K) radioactivity and total potassium in medicinal fungi from Yunnan in China

Evaluated has been radioactive contamination with ¹³⁷Cs in parallel to occurrence of ⁴⁰K and total K in 31 species of medicinal mushrooms from Yunnan, China. We chose species that were not previously studied. The activity concentrations of ¹³⁷Cs in the medicinal fungi in this study were low. The maximum values were 54 ± 4 Bq kg^-1 dry biomass (db) in caps and 48 ± 5 Bq kg^-1 db in stipes of saprotrophic fungus Gerronema xanthophyllum from the family of Tricholomataceae. Mushrooms with relatively higher activity concentrations of ⁴⁰K were among the non-polypore species but certain species from the genus Ganoderma such as G. applanatum, G. capense, G. philippii and G. sinense showed ⁴⁰K in the higher range of 900 ± 240 to 1400 ± 340 Bq kg^-1 db. The concentrations of total K in the fungal materials in this study were in the range from 2.9 ± 6.5 g kg^-1 db in Fomes rufolaccatus to 110 ± 6 g kg^-1 db in G. xanthophyllum. The species studied, which represented both some popular wood-decaying polypore fungi but also terrestrial forms from the herbal medicine of China, can be considered as little contaminated with ¹³⁷Cs and potentially good source of leachable K in extract and decoction or as a powdered form in capsules.

Radiometrical and physico-chemical characterisation of contaminated glass waste from a glass dump in Sweden

Around former glass factories in south eastern Sweden, there are dozens of dumps whose radioactivity and physico-chemical properties were not investigated previously. Thus, radiometric and physico-chemical characteristics of waste at Madesjö glass dump were studied to evaluate pre-recycling storage requirements and potential radiological and environmental risks. The material was sieved, hand-sorted, leached and scanned with X-Ray Fluorescence (XRF). External dose rates and activity concentrations of Naturally Occurring Radioactive Materials from ²³⁸U, ²³²Th series and ⁴⁰K were also measured coupled with a radiological risk assessment. Results showed that the waste was 95% glass and dominated by fine fractions (<11.3 mm) at 43.6%. The fine fraction had pH 7.8, 2.6% moisture content, 123 mg kg^-1 Total Dissolved Solids, 37.2 mg kg^-1 Dissolved Organic Carbon and 10.5 mg kg^-1 fluorides. Compared with Swedish EPA guidelines, the elements As, Cd, Pb and Zn were in hazardous concentrations while Pb leached more than the limits for inert and non-hazardous wastes. With ⁴⁰K activity concentration up to 3000 Bq kg^-1, enhanced external dose rates of ⁴⁰K were established (0.20 μSv h^-1) although no radiological risk was found since both External Hazard Index (H_ex) and Gamma Index (I_γ) were <1. The glass dump needs remediation and storage of the waste materials under a safe hazardous waste class 'Bank Account' storage cell as a secondary resource for potential future recycling.

Investigations on chemical composition and natural radioactivity levels from salt water and peloid used in pelotherapy from the Techirghiol Lake, Romania

The work presents the historical evolution, objectives, goals, concepts, chemical and radiometric methods, results and conclusions for salt waters and natural peloids used in pelotherapy. This study assesses chemical composition, natural radioactivity concentrations and the radiological hazard in peloid and salt water samples, from ten places in the Techirghiol Lake from Romania. Pelotherapy is a very important procedure, and thus, the materials used for this purpose must be well characterized to guaranty safety use. Concentrations of elements such as Sr, Ba, Mn, Fe, Sb, Zn, Cu, Pb, Ti, Ni, Cr, As have been measured using ICP-OES analytical technique. The natural radionuclides such as ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K have been determined by gamma-ray spectrometry. The average activity concentrations were of 0.48 ± 0.10 Bq/kg for ²³⁸U, 0.60 ± 0.10 Bq/kg for ²²⁶Ra, 0.30 ± 0.08 Bq/kg for ²³²Th and 17.5 ± 1.3 Bq/kg for ⁴⁰K for salt water samples. Also, the mean activity concentrations for peloids were: 5.70 ± 1.00 Bq/kg for ²³⁸U, 6.85 ± 1.60 Bq/kg for ²³²Th, 15.3 ± 3.7 Bq/kg for ²²⁶Ra and 95.8 ± 5.5 Bq/kg for ⁴⁰K. The results from this study contribute to the identification of possible contaminants in the salt water and peloid, and their association with the potential ecological and human health risk. In this context, of using salt water and peloid in a relatively long treatment period, several radiological indices have been calculated, to determine if the radionuclide's content can be also harmful to human health. The assessment indicates that humans are not exposed to concentrations of metal contaminants higher than the international recommended values.

Activity concentrations of 137Cs, 40K, and 210Pb radionuclides in selected medicinal herbs from Central Serbia and their effective dose due to ingestion

Specific activity of ¹³⁷Cs, ⁴⁰K, and ²¹⁰Pb radionuclides in fifteen selected medicinal herbs from three locations in Central Serbia (two mountains, Kopaonik and Zlatar, and a valley, Sokobanja) was measured using two semiconductor HPGe spectrometer systems. The obtained values are in intervals (<0.3 ÷ 9.7) Bq/kg, (<0.2 ÷ 24.7) Bq/kg, and (<0.2 ÷ 5.7) Bq/kg for ¹³⁷Cs; in intervals (125 ÷ 1100) Bq/kg, (104 ÷ 872) Bq/kg, and (103 ÷ 954) Bq/kg for ⁴⁰K, and in intervals (3.6 ÷ 49.0) Bq/kg, (3.9 ÷ 57.9) Bq/kg, and (2.8 ÷ 103) Bq/kg for ²¹⁰Pb, for herbs from Kopaonik, Sokobanja and Zlatar, respectively. The highest activity measured in individual herbs was: 24.7 Bq/kg for ¹³⁷Cs (Sokobanja valley), 1100 Bq/kg for ⁴⁰K (Mt. Kopaonik) and 103 Bq/kg for ²¹⁰Pb (Mt. Zlatar). The corresponding individual annual effective doses due to ingestion calculated from the measured activity concentrations, of the radionuclides are: in intervals (<1.7 ÷ 82.9) nSv, (<1.4 ÷ 211) nSv, and (<1.1 ÷ 48.7) nSv for ¹³⁷Cs; in intervals (0.76 ÷ 4.5) μSv, (0.64 ÷ 4.4) μSv, and (0.63 ÷ 4.9) μSv for ⁴⁰K, and in intervals (1.1 ÷ 18.2) μSv, (1.3 ÷ 21.6) μSv, (0.9 ÷ 38.3) μSv for ²¹⁰Pb, respectively. The specific activity concentration values of ¹³⁷Cs and ⁴⁰K obtained for the investigated herbs are similar to the literature data, while no information was found in literature about specific activity concentration of ²¹⁰Pb. The all values obtained for individual annual effective dose due to ingestion are less than 100 μSv, which means that the daily use of 200 mL of herbal infusion during a year made from the investigated herbs does not represent a radiological risk for health. However, a high individual annual effective dose of ingestion of ²¹⁰Pb obtained for some herbs indicate that their consumption in larger amounts 2-3 cups of infusion daily over a year could make the dose to exceed the recommended level, and points to necessity for extensive investigation of ²¹⁰Pb activity concentration worldwide.

STATISTICAL ESTIMATION OF RADIOLOGICAL HAZARDS FROM RADIONUCLIDE CONTENTS IN BUILDING MATERIALS

Thirteen (13) types of building tiles and Sharp sand commonly used for building purposes were collected for their radionuclide contents analysis using gamma ray spectrometry. The average value of the Radium equivalent activity is 208.81 Bq/kg for all samples considered was found to be lower than the recommended safe limit of 370 Bq/kg. Similarly, both external and internal hazard indices (Hex and Hin) were noted to have mean values of 0.57 and 0.73, respectively, which were lower than the recommended safe standard of 1. More so, the average absorbed gamma dose rate was observed to be 94.31 nGy/h, much higher than the recommended safe limit of 59 nGy/h.

MONITORING AND CHARACTERISATION OF NEW EVIDENCE OF NATURAL RADIONUCLIDES IN ROCK OUTCROPS IN PARAÍBA-BRAZIL

The radiometric monitoring carried out in the present study allowed the discovery of anomalous granite outcrops in natural radionuclides in the rural area of São Mamede in the state of Paraíba, Brazil. The characterisation study made it possible to determine maximum specific concentrations of approximately 199 kBq kg-1 of 238U, 85 kBq kg-1 of 226Ra, 26 kBq kg-1 of 232Th and 24 kBq kg-1 of 40K. Models for environmental dosimetry were applied, which resulted in obtaining the following quantities: radium equivalent (Raeq), indices of external (Hex), internal (Hin) and representative (Iyr) damage, and the effective outdoor dose (HE). The maximum results presented were approximately 123 kBq kg-1, 332, 562, 832, and 68 mSv y-1, respectively. Consequently, it was possible to define the region as of high radioactive background due to isolated rocky outcrops located in the rural area of the mentioned municipality.

ASSESSMENT OF NATURALLY OCCURRING RADIONUCLIDES IN MALAYSIA'S BUILDING MATERIALS

The activity concentrations of 226Ra, 232Th and 40K radionuclides from common building materials used by Malaysian people for construction purposes were studied using High-Purity Germanium (HPGe) detector. The measured activity concentrations of the aforementioned radionuclides range from 10 ± 1 Bq kg-1 (limestone) to 155 ± 61 Bq kg-1 (feldspar), 12 ± 3 Bq kg-1 (limestone) to 274 ± 8 Bq kg-1 (kaolin) and 62 ± 19 Bq kg-1 (limestone) to 1114 ± 20 Bq kg-1 (pottery stone) for 226Ra, 232Th and 40K, respectively. The measured activity concentrations of the natural radionuclides reported herein were found to be in accordance with other previous studies. In general, the activity concentration of the natural radionuclides revealed that all the determined values were below the recommended limit.

TERRESTRIAL RADIONUCLIDES IN SURFACE (DAM) WATER AND CONCOMITANT DOSE IN METROPOLITAN KUALA LUMPUR

Batu Dam is of considerable importance to the metropolis of Kuala Lumpur, its existence and the quality assessment of its waters being essential in helping to maintain the lives of a large sector of the Malaysian population. Concerning the level of naturally occurring radioactivity contained within its waters, a well characterised HPGe γ-ray technique has been used in making measurements of the concentrations of primordial radionuclides in samples of surface water from the Dam. Based on the mean individual daily consumption of dam water, estimation has been made of the concomitant radiation dose. Activity concentrations, in units of Bq l-1, have been found to be in the range 2.4-3.2 for 226Ra, 1.1-1.3 for 232Th and 22.7-40.7 for 40K, in line with literature data for surface waters. The total annual ingestion dose for infants (<1 y) and adolescents (12-17 y) are found to be significant and greater than the World Health Organization recommended maximum dose of 0.1 mSv y-1 from the imbibing of drinking water. However, the Dam water does not pose a threat to public health, the Dam water not being used as the sole source of drinking water. Noting that this is the only known study of water from Batu Dam, the reported levels allow for evaluation of future changes in the natural radioactivity profile.

RADIOACTIVITY OF SOIL IN THE REGION OF THE TOWN OF NIŠ, SERBIA

The concentration of radionuclides in samples of soil collected in the region of the town of Niš, was measured and presented in this paper. The naturally occurring radionuclides, 226Ra, 232Th and 40K, were found in all samples. In many of them, 137Cs was also measured, while the other artificial radionuclides were not detected. The measurements were carried out using the standard gamma spectroscopy system with high purity germanium (HPGe) detector. The results show that the average activity concentrations of 226Ra, 232Th, 40K and 137Cs are: 21, 26, 414 and 4.7, in Bq/kg, respectively. The sediment in the municipality spa Niška Banja exhibits a high content of 226Ra, 573 Bq/kg. The outdoor dose rates, due to the gamma radiation of the ground, were also determined for all soils. The average absorbed dose rate in air was estimated to be 39 nGy/h, while the corresponding annual effective dose is 0.048 mSv.

EVALUATION OF RADIATION DOSES AND HAZARD INDICES IN CRUSHED ROCKS FROM SOME QUARRIES IN IBADAN SOUTHWESTERN NIGERIA

The radiological assessment of rock samples from four quarry sites in Ibadan have been carried out. The mean activity concentrations of 40K, 226Ra and 232Th were 377.0 ± 37.9, 17.7 ± 3.6 and 4.98 ± 2.1 Bq kg-1, respectively, for Ratcon Quarry (RQ); 408.0 ± 28.7, 16.6 ± 1.6 and 10.6 ± 2.3 Bq kg-1, respectively, for Dekit Quarry; 388.0 ± 26.6, 15.7 ± 1.9 and 9.85 ± 3.9 Bq kg-1, respectively, for Hajaig Quarry; and 388.084 ± 55.9, 16.2 ± 3.9 and 12.1 ± 3.8 Bq kg-1, respectively, for NSCE Quarry (NQ). The highest mean outdoor effective dose of 0.038 ± 0.005 mSv y-1 and the minimum of 0.033 ± 0.004 mSv y-1 were obtained at NQ and RQ, respectively. The radiological hazard indices recorded in each site were <1.0. The results show lower radioactivity levels than the world average values; therefore, no serious radiological health effect is expected when the crushed rocks from the quarries are used for buildings construction.

ASSESSMENT OF RADIOLOGICAL HAZARDS OF USING PETROLEUM RAW MATERIALS AND THEIR WASTE

Activity concentrations of 238U, 232Th and 40K in raw and waste petroleum materials (Egypt and Kuwait) were measured using gamma ray spectrometer. The average values of 226Ra, 232Th and 40K were 21.1 ± 3.2, 7.6 ± 1.3 and 88.4 ± 8.2 Bq kg-1 for Egyptian samples while for Kuwaiti samples, they were 25.2 ± 3.4, 6.1 ± 2.2 and 67.8 ± 6.4 Bq kg-1, respectively. All samples had activity less than the exemption level recommended by the International Atomic Energy Agency. Moreover, radiological indices of radium equivalent, external, internal, alpha and gamma indices and radiation dose as well were calculated and their values were lower than the recommended regulatory limits. Thus, radiation exposure to petroleum materials did not present a significant radiological hazard.

Levels of radionuclide concentrations in benthic invertebrate species from the Balearic Islands, Western Mediterranean, during 2012-2018

Baseline levels of radionuclides in the marine environment of the Balearic Islands in Western Mediterranean have not been reported in literature. Because of their ecological role and acknowledged sensitivity to pollutants, herein, the activity concentrations of ²¹⁰Po, ⁴⁰K, ²¹⁰Pb, ⁹⁰Sr, and ²³⁴Th were measured in two types of benthic invertebrate species (mussels and sea urchins) sampled during 2012-2018. The activity concentrations of ²¹⁰Po, ⁴⁰K, ²¹⁰Pb, and ²³⁴Th ranged from 38 ± 1 to 325 ± 11 Bq kg^-1 dry weight (d.w.), 220 ± 10 to 996 ± 46 Bq kg^-1 d.w., ND (lower than the limit of detection) to 55 ± 8 Bq kg^-1 d.w., and ND to 70 ± 15 Bq kg^-1 d.w., respectively. In all cases, no artificial ⁹⁰Sr activity was detected in the collected samples. The committed effective dose to humans was calculated to be in the range of 48-640 μSv year^-1.

137Cs and 40K in Cortinarius caperatus mushrooms (1996-2016) in Poland - Bioconcentration and estimated intake: 137Cs in Cortinarius spp. from the Northern Hemisphere from 1974 to 2016

Cortinarius caperatus grows in the northern regions of Europe, North America and Asia and is widely collected by mushroom foragers across Europe. This study shows that in the last three decades since the Chernobyl nuclear accident, C. caperatus collected across much of Northern Poland exhibited high activity concentrations of radiocaesium (¹³⁷Cs) - a long-lived radionuclide. The mushroom appears to efficiently bioconcentrate ¹³⁷Cs from contaminated soil substrata followed by sequestration into its morphological parts such as the cap and stipe which are used as food. The gradual leaching of ¹³⁷Cs into the lower strata of surface soils in exposed areas are likely to facilitate higher bioavailability to the mycelia of this species which penetrate to relatively greater depths and may account for the continuing high activity levels noticed in Polish samples (e.g. activity within caps in some locations was still at 11,000 Bq kg^-1 dw in 2008 relative to a peak of 18,000 in 2002). The associated dietary intake levels of ¹³⁷Cs have often exceeded the tolerance limits set by the European Union (370 and 600 Bq kg^-1 ww for children and adults respectively) during the years 1996-2010. Human dietary exposure to ¹³⁷Cs is influenced by the method of food preparation and may be mitigated by blanching followed by disposal of the water, rather than direct consumption after stir-frying or stewing. It may be prudent to provide precautionary advice and monitor activity levels, as this mushroom continues to be foraged by casual as well as experienced mushroom hunters.

BASELINE EVALUATION STUDY OF NATURALLY OCCURRING RADIONUCLIDES IN SOIL SAMPLES FROM VICINITY OF INDIA'S FIRST FAST REACTOR FUEL CYCLE FACILITY (FRFCF), DAE COMPLEX, KALPAKKAM, INDIA

The activity concentration of 238U, 232Th and 40K were measured in the soil samples collected from Fast Reactor Fuel Cycle Facility (FRFCF) site, using high-resolution gamma-ray spectrometry. This study is aimed to establish the baseline data of naturally occurring radionuclides within the site. The average activity concentrations were found to be 416.5, 61.7 and 622.3 Bq kg-1 for 40K, 238U and 232Th, respectively. The activity concentrations and its radiological indices were evaluated and were compared with the international values reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The ratio of 40K/232Th and 40K /238U were calculated, which indicates the presence of 5.79 and 2.69 times more K-bearing minerals as compared with Th and U-bearing minerals in the soil samples, respectively. The study provides baseline information on concentration of radionuclides and background radiological assessment of the FRFCF site.

RADIATION EXPOSURE FROM NATURAL RADIONUCLIDES IN BUILDING MATERIALS

Building materials from Iberian Peninsula (Portugal and Spain) were collected and analysed for 226Ra, 232Th and 40K using HPGe gamma-ray spectrometers. The results show that the highest mean value of 226Ra and 232Th activities are 2168 and 390 Bq kg-1, respectively, measured in zircon. For 40K, this value is 1290 Bq kg-1, measured in granite. The mean concentrations of the three radionuclides in the different building materials, excluding the zircon and the industrial by-products (ashes, gypsum and phosphogypsum), are 62, 31 and 519 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The radiological health hazard parameters: radium equivalent activity (Raeq), activity concentration index (I) absorbed and effective dose rates, associated with these radionuclides, were evaluated. These values are within the EU recommended limits in building materials, except for same samples of aggregates, granites, ceramics, phosphogypsum and zircon. This study will contribute for the worldwide data pooling on the radioactivity of the building materials.

Radionuclide Concentrations in Different Water Sources From Nigeria

Gamma spectrometric analysis was done on all the different sources of water samples in the rural communities of Egbeda Local Government Area of Oyo State in Nigeria. Water samples were collected from 6 boreholes, 11 streams, 5 taps, and 41 hand-dug wells. The water samples were analyzed using a high-purity germanium detector at the National Institute of Radiation Protection and Research, Ibadan, Nigeria. Radionuclides found in the water samples include K, Th, and U. The average amount of K found in the borehole, stream, tap, and well water is 3.22, 2.23, 2.11, and 1.77 Bq L, respectively. The average amount of Th found in the borehole, stream, tap, and well water is 0.57, 0.46, 0.47, and 0.55 Bq L, respectively. The average amount of U found in the borehole, stream, tap, and well water is 0.54, 0.27, 0.29, and 0.61 Bq L, respectively. The annual effective doses calculated from radionuclides in the water are 0.11, 0.09, 0.09, and 0.11 mSv for borehole, stream, tap, and well, respectively.

Gamma dose rate distribution in the Unegt subbasin, a uranium deposit area in Dornogobi Province, southeastern Mongolia

Unegt subbasin in Dornogobi Province, southeastern Mongolia, contains the Dulaan Uul uranium deposit, for which development for commercial mining has been conducted as of 2015. Zuunbayan is a commune located close to the Dulaan Uul uranium deposit, and residents of Zuunbayan and their livestock can easily approach the uranium deposit area, including an aboveground dump site, which was created as a result of the mining development. The present study measured and analyzed the gamma dose rate (absorbed dose rate in air) distribution in Unegt subbasin using data collected from a car-borne measurement survey. The gamma dose rate increased from the northern (45-65 nGy/h) to the central (50-69 nGy/h, including Zuunbayan) and the southern (54-195 nGy/h, including Dulaan Uul) parts of the study area. The gamma dose rates (up to 195 nGy/h) around the dump site in Dulaan Uul were significantly higher than the background level (< 80 nGy/h) at several points. Additional in-situ measurements showed that the gamma dose rates reached up to 450 nGy/h at these locations, which was primarily attributed to the gamma radiation emitted by ²³⁸U series elements. Spatial distribution of gamma dose rates around the dump site revealed that the gamma radiation did not originate from the dump, but from the ground, at the measurement points. Analysis of collected soil samples showed that ²³⁸U and ²²⁶Ra were concentrated in deeper soil. These results indicate that the gamma dose rates higher than the background level were not associated with the aboveground mine dump; rather, they were very probably caused by presence of uranium deposits close to the ground surface.

A study of the radiological baseline conditions around the planned Sinop (Turkey) nuclear power plant using the mapping method

This study makes a first attempt at a detailed estimation of the background radioactivity level and its distribution at the Sinop nuclear power plant site. The activity concentration levels of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs radionuclides in soil samples collected from 88 locations around Sinop Province, Turkey, in November 2016, were measured using gamma spectrometry. The distributions of radionuclide levels obtained from the results were evaluated using a geostatistical method, and the estimated radiation levels were determined using the ordinary kriging (OK) method, which is the best linear unbiased estimator (BLUE) for unmeasured points. Estimates of distribution results were evaluated using cross-validation diagrams, and it was shown that the OK method could predict radiological distributions for appropriate criteria. Finally, using the kriging parameters, distributions of radiation levels for the entire work area were mapped at a spatial resolution of 100 × 100 m². These maps show that the natural radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K) are distributed at higher levels to the southeast of Sinop than in the other regions, and the activity of an artificial radionuclide (¹³⁷Cs) is high in the interior and northern sections.