Average Activity Concentrations Research Articles

ASSESSMENT OF RADIOLOGICAL HAZARD FOR VARIOUS FOOD COMMONLY USED IN REPUBLIC OF NORTH MACEDONIA

Consuming food containing radionuclides is particularly dangerous. If anyone ingests or inhales a radioactive particle, it continues to irradiate the body as long as it remains radioactive and stays in the body. However, studies on the radioactivity of consumable foods assume importance as it is necessary to estimate the ingestion dose to the public. Due to all this, the focus of this research was on determining the activity concentrations of 226Ra, 40K and 232Th. Forty-nine samples in three categories of vegetables, cereals (rice, wheat, corn), and milk, were collected from local markets (city of Skopje) in the Republic of North Macedonia and they were analyzed by using high-purity germanium (HPGe) detector to assess natural and artificial radioactivity. The average activity concentrations of 226Ra, 40K and 232Th of the tested samples were 2.85±1.15, 2.48±0.85, and 80.64±5.45 Bq kg-1, respectively. No artificial radionuclide was found in any of these samples. The average value of the radium equivalent activity in all samples was 12.56 Bq kg-1, which was less than the maximum permitted value of 370 Bq kg-1. The values ​​of the external hazard indices for vegetables, cereals and milk samples vary with an average value of 0.11, which is less than one in all samples indicating the non-harmfulness of the samples. The mean activity concentrations of 226Ra, 40K and 232Th (Bq kg-1) in the samples were used to calculate the absorbed dose rate whose mean value for all food samples was 6.16 Bq kg-1. It was determined that the measured values are within the globally accepted values, i.e., they are quite lower than the data in literature. These data would be useful to establish a baseline for natural radioactivity concentrations in food products consumed in the Republic of North Macedonia.

Measurement of radiological parameters in harvested sand in Bungoma county rivers, Kenya

samples of sand were collected along the course of ten selected rivers two from each river through random sampling. Activity concentration of 238U, 232Th and 40K were measured using high resolution NaI(Ti) gamma ray spectrometer. Activity concentration of the three primordial radionuclides obtained were used to calculate, absorbed dose rate, annual effective dose rate, interna and external hazard indices and radium equivalent. The average activity concentration for the three primordial radioactive nuclides were; 2±0.1Bq/kg with a range of 0± 0.03Bq/kg to 4±0.24Bq/kg for 238U, 55±2.78Bq/kg with a minimum value of 32±1.6Bq/kg and a maximum value of 87±4.38Bq/kg for 232Th and 51±2,56Bq/kg with a minimum value of 27±1.37Bq/kg and a maximum value of 76±3.8Bq/kg for 40K. The mean activity concentrations for 238U and 40K were below the world averages of 33Bq/kg and 420Bq/kg respectively.  The indoor and outdoor annual effective dose rate varied from 0±0mSv/y to 0.2±0.01mSv/y with an average of 0.1±0 mSv/y and 0±0.003mSv/y to 0.1±0.009mSv/y with a mean of 0.1±0.006 mSv/y respectively. The annual effective dose rates were below the safe limits of 1mSv/y. Therefore, use of sand from the selected rivers in Bungoma County, Kenya for construction has minimal health risks to the inhabitants.

Assessment of Activity Concentration of Radionuclides in Soil and Cassava Food Crop from Solid Mineral Mining Site in Ishiagu, Ivo L.G.A of Ebonyi State, Nigeria

The assessment of activity of concentration of radionuclides in soil and food crops from solid mineral mining sites at Ishiagu, in Ivo L.G.A of Ebonyi State was carried out using the necessary measuring instruments. Samples of soil and cassava crop collected from around the mining sites. The samples were analysed using gamma ray spectrometry. The average activity concentration of 226Ra, 232Th and 40K in soil samples were 12.37,16.08, and 144.29 Bqkg-1 while those for cassava were 2.81, 16.80, and 205.41 Bqkg-1. The soil/plant radionuclide transfer ratio estimated are 0.62, 2.43 and 2.51 for 226Ra, 232Th and 40K, respectively. All the radiological risk parameters estimated are relatively low. The result of this work showed that the obtained results for all samples were lower than the international accepted limit. Hence, from radiological health standpoint, the obtained values of effective doses may not pose significant threat to both human and the environment.

FIELD MEASUREMENT OF THE UNATTACHED FRACTION AND ACTIVITY CONCENTRATION RATIO OF RADON PROGENY IN TYPICAL DWELLINGS.

The unattached fraction (fp) and activity concentration ratio of radon progeny (${\boldsymbol C}_{{}{}^{\bf 218}\bf{Po}}:{\boldsymbol C}_{{}{}^{\bf 214}\bf{Pb}}:{\boldsymbol C}_{{}{}^{\bf 214}\bf{Bi}}$) are important for radon exposure dose evaluation. For getting these characteristic parameters in dwellings, a series of field measurement was carried out. For comparison, a semi-continuous measurement was carried out in an office room and outdoors. Results show that the average fp is 4.5%±2.2% and 3.8%±1.7% in city dwellings and in rural dwellings, respectively. The average activity concentration ratios are 1:0.94:0.70 for radon progeny and 1:0.07:0.06 for unattached radon progeny in city dwellings, while those in rural dwellings are 1:0.88:0.66 and 1:0.09:0.07. The average values of fp are 5.1%±0.9% and 5.4%±3.1% in the office room and in outdoors without significant difference. The average activity concentration ratios are 1:0.88:0.77 for radon progeny and 1:0.11:0.11 for unattached radon progeny in outdoors.

Determination of radioactivity levels in feldspathic dental ceramics

Activity concentrations of 42 different feldspathic dental ceramic powders were determined using a gamma spectrometer with an HPGe detector. The average 238U, 232Th and 226Ra activity concentrations of the specimens were 126 ± 8 Bq kg−1, 5.6 ± 0.5 Bq kg−1 and 12.7 ± 1.2 Bq kg−1, respectively. The average 40K activity was found as 2855 ± 89 Bq kg−1 ranging from 2252 ± 70 Bq kg−1 to 3522 ± 110 Bq kg−1 due to high potassium content in dental ceramics. None of the activity concentration measurements exceeded the limits by EC and ISO.

Natural radioactivity level in fly ash samples and radiological hazard at the landfill area of the coal-fired power plant complex, Vietnam

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of 238U, 226Ra, 232Th and 40K were 93, 77, 92 and 938 Bq kg−1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y−1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30 ×10−3, 4.26 ×10−3, 0.62 ×10−3, and 25.61 ×10−3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

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.

Applying in-Situ and Laboratory-based Gamma Spectrometry to Determine Activity Concentration and Distribution of 40K, 226Ra and 232Th in Abeokuta, Southwest Nigeria

Abstract: The applications of radionuclides are potential sources of health risk and also a concern in the area of nuclear security. It is therefore imperative to determine the presence of the different radionuclides present in the environment at all times, because it is necessary to control and assess the risk level in the environment. The present study compares activity concentrations of the primordial radionuclides 40K, 226Ra and 232Th obtained from laboratory gamma spectrometry measurements with the activity concentrations of the radionuclides as obtained from in-situ measurements. Soil samples were randomly collected from nineteen different points within Abeokuta city ensuring good coverage of the city area. A mobile gamma spectrometry system was used to collect gamma spectra measurements in the field. The obtained values are presented. The ranges of activity concentrations for 40K, 226Ra and 232Th have been found to be 113 – 1975, 5 – 128 and 181 – 3284 Bqkg-1, respectively for laboratory gamma spectrometry and 104 – 1312, 31 – 121 and 104 – 2578 Bqkg-1, respectively for in-situ gamma spectrometry measurements. This study showed that the average activity concentrations of the primordial radionuclides in Abeokuta were much higher than worldwide averages of 400, 35 and 30 Bqkg-1 for 40K, 226Ra and 232Th, respectively. From both methods, 232Th is seen to be the major contributor to the environmental radioactivity of Abeokuta. Good correlations also were deduced between the activity concentration results obtained from laboratory and in-situ gamma spectrometry, which therefore implies a significant relationship between the two methods used in the study. Keywords: In-situ gamma, Gamma spectrometry, Activity concentration, Radionuclides.

Transfer from soil to grass and statistical analysis of naturally occurring radionuclides in soil from phosphate mining and processing sites in Maritime Region of Togo

Natural radionuclides activity concentrations of 226Ra, 228Ra, and 40K in soil and grass samples, statistical analysis of these radionuclides, and transfer factors (TFs) from soil to the grass were carried out from phosphate mining and processing sites in southern areas of Togo using gamma-ray spectrometry-based high-purity germanium (HPGe) detector. The average activity concentrations of 226Ra, 228Ra, and 40K were found within the range usually measured worldwide. Statistical analysis was done by investigating the skewness, the kurtosis, and the density distribution of radionuclides in the study areas. Both skewness and kurtosis displayed that the activity concentrations of soil and grass samples in the discharge waste site (Kpémé) and mining site (Hahotoé) exhibited slightly positively skewed, negatively skewed, leptokurtic, and platykurtic distributions. The TFs for 226Ra, 228Ra, and 40K from discharge waste soil to grass were evaluated. The average transfer factors of 226Ra, 228Ra, and 40K in the phosphate processing area were found to be 0.16, 0.32, and 8.42, respectively. 226Ra and 228Ra TFs values were found to be within the limit of worldwide measure values, while that of 40K was found to be larger than the values measured in other countries. The average TF value of 8.42 for 40K was eight times higher than the average value of unity, showing its large intake by vegetables. The high TFs for 40K could be explained by the extensive application of phosphate fertilizers to soils when growing vegetables.

Measurement of Natural Radionuclides and Radon Gas Concentration in Surface Soil samples within Jalingo Metropolis, North East Nigeria

Activity concentrations of radionuclides (226Ra, 232Th, 40K) and radon gas in soil samples collected within Jalingo Metropolis were assessed by gamma spectrometric techniques using Na (TI) scintillation detector. The result showed an average activity concentration of 226Ra, 232Th and 40K to be 18.626±7.31 Bq/kg, 16.709±10.96 Bq/kg and,167.935±389.33 Bq/kg. The concentrations of 226Ra, 232Th were lower than the world average value while 40K was far higher that the recommended value.Most people in the study area use soil for building construction therefore, it was necessary to asses if there are any radiological hazards associated with the soil. This was achieved by determining Radium equivalent activity (Raeq), internal hazard index (Hin) and Annual effective dose rate. The result indicates that the indices are within normal limit. The Radon concentration in soil varies 11.126±1.315 kBq/kg to 30.374±3.331 kBq/kg with a mean value of 17.881±7.019 kBq/kg which is within the safety limits. Generally, the result showed that the soil in the study area might not pose major hazard to the members of the public

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.

Radon protection in apartments using a ventilation system wireless-controlled by radon activity concentration

The new German Radiation Protection Act (StrlSchG) of 31 December 2018 established a reference value of 300 Bq m−3 for the annual average radon activity concentration in buildings with recreation and living rooms, as well as in workplaces. It is expected that the reference value will be exceeded in a vast number of buildings throughout Germany and that radon protection measures will become indispensable. A simple and inexpensive radon protection measure for existing buildings is ventilation. In the scope of a joint project, ventilation systems with zone control and heat recovery are to be extended by the control parameter radon activity concentration. A highly sensitive, miniaturized radon monitor will be developed for this purpose, which can be integrated wirelessly into ventilation systems. Radon measurements were carried out in 13 apartments of an unoccupied heated apartment block in Germany over a period of three weeks in the wintertime. High radon activity concentrations were found on all three floors. The maximum values were 14000 Bq m−3 on the first floor, 6000 Bq m−3 on the second floor, and 2000 Bq m−3 on the third floor. Ventilation experiments were carried out in an apartment with high radon activity concentration. Two decentralized ventilation systems with heat recovery were installed in each of the two opposite outside walls. The controlling device of the system was activated wirelessly depending on the radon activity concentration. The radon activity concentration was reduced from 8000 Bq m−3 to 800 Bq m−3 in a first experiment in the living room.

Radon Spatial Variations in University’s Buildings Located in an Italian Karst Region

In the framework of a collaboration between INAIL and University of Salento, an indoor radon survey in 54 buildings belonging to the UniSalento University (Southeast Italy) was carried out. The monitored buildings differ by type, construction period, materials, etc., and are located in an area with a morphology characterized mainly by marls, calcareous marls, and calcarenites (karst area). The sample of the survey includes 963 rooms at different floors: it consists in rooms mainly located at ground floor (67%), first floor (12%), and below ground (12%). SSNTD passive dosimeters measured the average radon activity concentration for two consecutive semesters (spring/summer and autumn/winter) from which annual radon averages were estimated for each room. The spatial variability within buildings was investigated in terms of variation between floors and among rooms at the same floor. Data analysis provides evidence that the distributions (in terms of arithmetic mean, standard deviation, median, and geometric mean) of indoor radon annual averages at ground floor and at first floor within building are very similar. This highlights that the karstic characteristics of soil and building materials affect radon levels not only below ground and at ground floor, but also at first floor. Moreover, to evaluate the spatial variability of radon among buildings or floors, the analysis of the distribution of coefficient of variation (CV) was carried out: the results show a low spatial variability with median and average values of CVs ≤ 30% both for the whole building and at different floor levels.

Radiometric analysis of micas used in many industries and evaluation of radiological hazards

Abstract Mica group minerals have been utilized in various industries such as paint, cement, rubber, plastic, paper, automotive, cosmetics, textile, etc. due to their unique electrical, thermal, and mechanical properties. In this study, the radiometric properties of 58 mica samples collected from three quarries operated commercially in Turkey were investigated using gamma-ray spectroscopy with an HPGe detector. The average activity concentrations of 226Ra, 232Th, and 40K analyzed in mica samples were found as 12, 44, and 2763 Bq kg−1, respectively. The radon emanation coefficient and radon mass exhalation rate of mica samples varied from 4 to 22% with an average of 10% and 0.4–5.9 µBq kg−1 s−1 with an average of 2.6 µBq kg−1 s−1, respectively. The radiological hazard caused by the utilization of mica samples as raw materials in the cement and concrete industry was evaluated for adults by calculating the gamma index and annual effective dose due to external exposure indoor. The study results revealed that there are no significant radiological hazards associated with the utilization of mica samples as building raw materials.

ASSESSMENT OF NORM LEVELS AND RADIOLOGICAL HAZARDS FROM PETROLEUM EXTRACTION IN THE ONSHORE OIL FIELDS, EGYPT.

Forty-nine different samples (crude oil, surface soil, produced water and sludge) from onshore oil fields in the Western Desert of Egypt were assessed for naturally occurring radioactive material (NORM) levels using HPGe gamma-ray spectrometer. The average activity concentrations of 226Ra, 232Th and 40K were 25±1.3, 26±1.0 and 21±1.5; 9.8±0.50, 11±0.40 and 94±6.9; 130±6.6, 91±3.4 and 41±3.0; and 180±16, 70±6.9 and 1300±110Bqkg-1 for crude oil, surface soil, produced water and sludge, respectively. The obtained NORM levels are much below the International Atomic Energy Agency NORM clearance levels. Radiological parameters (radium equivalent activity, absorbed dose rate and annual effective dose) were calculated and compared with the international acceptable limits. The annual effective doses are below 1 and 20mSv, the ICRP safety limits for the public and workers, respectively. Consequently, insignificant radiological hazards could present for the workers and surrounding environment from petroleum extraction activities in the studied area.

Assessment the Natural Radioactivity of Radionuclides ( 226Ra, 232Th, 40K, and 137Cs) in Wheat Grain

This paper investigates the activity concentration of radionuclides (226Ra, 232Th, 40K and 137Cs) in the wheat grain samples using a high-purity germanium detector. Thirty-six wheat grain samples were collected from different locations of Koya City, Iraqi Kurdistan region. Average activity concentrations of 226Ra, 232Th and 40K in wheat grain are found to be 0.407 ± 0.097 Bq.kg-1 for 226Ra, 0.36 ± 0.14 Bq.kg-1 for 232Th and 109.25± 2.214 Bq.kg-1 for 40K, respectively. The measured activity concentrations for the radionuclides are compared with the reported data from other countries. In addition, the fallout radionuclide of 137Cs has no detection of in the wheat grain samples. The radium equivalent activity Raeq, internal and external hazard indices Hin and Hex, and annual gonadal dose equivalent are calculated for the measured samples. The total ingestion dose is 113.19 µSv.y-1, which is below the world average value of 290 µSv.y-1.

The status of NORMs in natural environment adjacent to the Rooppur nuclear power plant of Bangladesh

The Rooppur Nuclear Power Plant (RNPP), the first nuclear power plant in Bangladesh with a capacity of 2.4 GWe, is under construction on the bank of the river Padma, at Rooppur in Bangladesh. Measurement of background radioactivity in the natural environment adjacent to RNPP finds great importance for future perspectives. Soil and sediment samples collected from upstream and downstream positions of the Padma River (adjacent to RNPP) were collected and analyzed by HPGe gamma-ray spectrometry for primordial radionuclides. The average activity concentrations (in Bqkg−1) of 226Ra, 232Th and 40K radionuclides in soil samples were found to be 44.99 ± 3.89, 66.28 ± 6.55 and 553 ± 82.17 respectively. Respective values in sediment samples were found to be 44.59 ± 4.58, 67.64 ± 7.93, 782 ± 108. Relevant radiation hazard indices and dosimetric parameters were calculated and compared with the world average data recommended by US-EPA. Analytical results show non-negligible radiation hazards to the surrounding populace. Measured data will be useful to monitor any change of background radioactivity in the surrounding environment of RNPP following its operation for the generation of nuclear energy.

Gross alpha activity in urban sediments as an important indicator of urban environmental processes on the example of three Russian cities

The protection of the urban environment from radioactive wastes (including technologically enhanced natural radionuclides) and potentially harmful elements have recently become very critical. Thus, the present study aimed to assess the radioactive levels in low-volume samples of dust and fine sand fractions of the urban surface deposited sediments (USDS) collected in three Russian cities. The detection was conducted via CR-39 and LR-115 type II solid-state nuclear track detectors (SSNTDs) have been used to detect gross alpha activity concentrations. A statistically significant difference was observed between the average gross alpha activity concentrations in the dust fraction and the fine sand fraction in each city. The obtained results also illustrate the gross alpha activity concentration in the dust fraction is higher than in the fine sand fraction. This is consistent with the results of the chemical and mineralogical analysis.The dust fraction size has a higher gross alpha activity concentration than the fine sand fraction due to the natural partitioning of the main minerals constituting USDS with trace uranium and thorium content (feldspar, plagioclase, amphibole and others) and negligible uranium and thorium content (quartz). In some cases, USDS radioactivity is associated with monazite and zircon. A good correlation (0.58) was found between the gross alpha activity concentration and the effective content of uranium and thorium. Finally, an assessment of the gross alpha activity concentrations in the USDS size fractions was considered an essential indicator of environmental processes that are significant in terms of their impact on human health.

Baseline radioactivity and associated radiological hazards in soils around a proposed nuclear power plant facility, South-South Nigeria

Increased concerns about human population exposure to increased ionizing radiations emanating from anthropogenic sources of radiation, as well as the associated environmental risk, have necessitated radioactivity baseline studies in many regions. This work based on standard procedures designed suite nuclear power plant (NPP) radiological monitoring plan was conducted to assess the radiological baseline of Itu, Nigeria (5ο10′0 N, 7°59′0 E). A total of 44 soil samples were collected and analyzed using High Purity Germanium detector. The average activity concentration values for soil samples were 47.98 ± 8 Bqkg−1226 for Ra, 15.15 ± 1 Bqkg−1 for 238U, 38.65 ± 6 Bqkg−1 for 232Th, and 41.55 ± 6 Bqkg−1for 4 K. These mean values were lower than the UN Scientific Committee on the effects of atomic radiation's world mean values of 33, 45, and 420 Bqkg−1 for 238U/226Ra, 232Th, and 4 K, respectively. The hazard indices calculated using the measured activity concentrations indicated 32.04 nGy/h, 0.042 mSv/yr, and 0.17 mSv/yr for mean GDR, outdoor, and indoor AEDE, respectively. In addition, the average radium equivalent resulting from terrestrial gamma of activity concentration was 113.94 Bqkg−1, with a mean ELCR of 0.15 × 10−3. These baseline data show that there is no substantial radiological concern for human health.

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.