Evaluation of dose parameters and radiological hazards in gravel samples of Konyaaltı Beach,Antalya

It is important to know the distribution and transfer of radionuclides such as uranium, thorium, and potassium, which exist naturally in the environment we live in. For this reason, measurements of these natural radionuclides have been carried out for 15 gravel samples collected from Konyaalt? Beach, Antalya. In order to measure the natural activity concentrations of potassium-40, uranium-238, and thorium-232 radionuclides, we performed the measurements by applying a gamma spectrometry method with a “3?×?3” NaI(Tl) detector, which is a multichannel analytical detector in the Suleyman Demirel University gamma spectrometry laboratory. The minimum, maximum, and mean values for the ²²⁶Ra activity concentration were measured as 19.74 Bq/kg, 37.03 Bq/kg, and 31.64 Bq/kg, respectively. The minimum, maximum, and mean values for the ²³²Th activity concentration were measured as 12.76 Bq/kg, 34.32 Bq/kg, and 26.67 Bq/kg, respectively. The minimum, maximum, and mean values for the ⁴⁰K activity concentration were measured as 196.37 Bq/kg, 421.13 Bq/kg, and 350.42 Bq/kg, respectively. Dose parameters and radiation damage indices were calculated using experimentally measured activity results and the resulting dose and hazard index values were compared with the determined limit values. It can be concluded that no risk may threat in terms of the hazard index values. In addition, all results obtained in terms of calculated dose values except for annual gonadal dose are below the recommended limit values.     

Estimation of excess lifetime cancer risk and radiation hazard indices in southern Iraq

Relatively high activity concentrations of some radionuclides (²²⁶Ra, ²³⁸U, ²³²Th, and ⁴⁰K) have been measured in surface and subsurface soils in areas (southern Iraq) where many warfare actions have taken place during the Iran–Iraq and Gulf wars. Such high activity concentrations might be related to the increase in cancerous injuries and birth defects recently reported. The study was aimed to estimate the activity concentrations of some nuclides and a comparison of results with international health hazard indices. In addition, the excess lifetime cancer risk (ELCR) was assessed. Soil samples were collected at three depths (0, 30, and 60 cm) in three locations in Abu Al Khasib and Ad Dayr in Basrah governorates. The average activity concentrations were estimated employing hyper-pure germanium HPGe gamma-ray detection technology. The values obtained in Abu Al Khasib were: 58.44 Bq/kg (²²⁶Ra), 43.56 Bq/kg (²³⁸U), 19.38 Bq/kg (²³²Th), and 321.76 Bq/kg (⁴⁰K) whereas in Ad Dayr 45.71 Bq/kg (²²⁶Ra), 35.53 Bq/kg (²³⁸U), 20.33 Bq/kg (²³²Th), and 337.02 Bq/kg (⁴⁰K). According to UNSCEAR (Sources and effects of ionizing radiations: a report on the effects of atomic radiation to the general assembly with scientific annexes, Annex B, United Nations, New York, 2000) report, higher levels of ²²⁶Ra, ²³⁸U concentrations than the world’s average values (35 Bq/kg) were observed in both locations. In addition, some radiation hazard indices were determined for both locations: average outdoor external dose (D _out), average indoor external dose (D _in), total average value of the external dose (D _tot), average annual outdoor effective dose (E _out), average annual indoor effective dose (E _in), and averaged total annual effective dose (E _tot). Values for D _tot and E _tot were higher than the worldwide median (143 nGy/h and 0.48 mSv/y, respectively) in both regions. The measured values of activity concentrations were also used to estimate the outdoor, indoor, and total ELCR. The ELCR values were higher than the worldwide averages. Further analyses and studies need to assess the real risks for human health and possible soil remediation.     

Naturally occurring radionuclides and their geochemical interactions at a geothermal site in the North German Basin

The activities of the most common, naturally occurring radionuclides ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²²⁸Ra, ²²⁸Th, and ⁴⁰K were measured by gamma-ray spectrometry in samples from reservoir rocks, geothermal fluids, and mineral precipitates at the geothermal research site Groß Schönebeck (North German Basin). Results demonstrated that the specific activity of the reservoir rock is within the range of the mean concentration in the upper earth crust of <800 Bq/kg for ⁴⁰K and <60 Bq/kg for radionuclides of the ²³⁸U and ²³²Th series, respectively. The geothermal fluid showed elevated activity concentrations (up to 100 Bq/l) for ²²⁶Ra, ²¹⁰Pb, and ²²⁸Ra, as compared to concentrations found in natural groundwater. Their concentration in filter residues even increased up to 100 Bq/g. These residues contain predominantly two different mineral phases: a Sr-rich barite (Sr, BaSO₄) and laurionite (PbOHCl), which both precipitate upon cooling from the geothermal fluid. Thereby they presumably enrich the radionuclides of Ra (by substitution of Ba) and Pb. Analysis of these precipitates further showed an increased ²²⁶Ra/²²⁸Ra ratio from around 1–1.7 during the initial months of fluid production indicating a change in fluid composition over time which can be explained by different contributions of stimulated reservoir rock areas to the overall produced fluid.     

Measurement of natural radioactivity in sand samples collected from the Baoji Weihe Sands Park, China

The activity concentrations and the gamma-absorbed dose rates of the primordial naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K were determined for sand samples collected from the Baoji Weihe Sands Park, China, using γ-ray spectrometry. The natural radioactivity concentration of sand ranges from 10.2 to 38.3 Bq kg⁻¹ for ²²⁶Ra, 27.0 to 48.8 Bq kg⁻¹ for ²³²Th and 635.8 to 1,126.7 Bq kg⁻¹ for ⁴⁰K with mean values of 22.1, 39.0 and 859.1 Bq kg⁻¹, respectively. The concentrations of these radionuclides are compared with the typical world values and the average activity of Chinese soil. The measured activity concentration of ²²⁶Ra and ²³²Th in sand is lower than the world average while that of ⁴⁰K is higher. . To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate, and the effective dose rate have been calculated and compared with internationally approved values. The radium equivalent activity values of all sand samples are lower than the limit of 370 Bq kg⁻¹. The values of the external hazard index are less than unity. The mean outdoor air absorbed dose rate is 69.6 nGy h⁻¹ and the corresponding outdoor effective dose rate is 0.085 mSv y⁻¹.     

Estimation of radiation exposure in soils and organic (animal) and inorganic (chemical) fertilizers using active technique

In this study, activity concentrations of ⁴⁰K, ²²⁶Ra and ²³²Th in fertilized soil samples and different organic and inorganic fertilizers used in agricultural soil were analysed using gamma-ray spectrometry NaI (Tl) detector in order to access the implications of extended use of fertilizers in 2–3 years. The concentrations of radionuclides in some granular fertilizer brands were discovered to be higher for ⁴⁰K, ²²⁶Ra and ²³²Th than those obtained in leafy fertilizer, animal fertilizer and fertilized soil samples. From the results, the highest overall mean concentrations of the specific activities of ⁴⁰K, ²²⁶Ra and ²³²Th were 2301.8 (granular fertilizer), 42.5 (leafy fertilizer) and 327.1 (animal fertilizer) in Bq kg^?1, while the lowest values observed in the specific activities of the same radionuclides were 357.7 (leafy fertilizer), 28.1 (animal fertilizer) and 36.5 (animal fertilizer). The radiological hazards of the radium equivalent (Ra_eq), normative value (NRN), outdoor radium equivalent (Ra_eq-out), external hazard index (H _ext), internal hazard index (H _in), dose rate, annual effective dose rate, activity utilization index and concentration accumulation index (CAI) and Ra_FZ due to the presence of these radionuclides in the investigated samples were calculated. Nevertheless, some of the fertilizer brands have higher concentration values than the recommended limit, and the values of hazard indices of fertilizer brands used in the selected teaching and research farms were within acceptable limit. Therefore, the fertilized soil samples in the studied farms are safe.     

Natural radionuclide survey in the coastal strip of the 290 Ramsar site,Uruguay

An initial on-going survey of the activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K for sand samples collected within the coastal strip of 290 Ramsar site evaluated the external hazard index, the outdoor annual effective dose equivalent and the radium equivalent activity, to elucidate potential risks for the resident inhabitants. The range of mean activity concentrations in the whole area for ²²⁶Ra, ²³²Th and ⁴⁰K were between 4.12?±?0.26 and 48.3?±?1.4, 5.47?±?0.55 and 194?±?13, 77.7?±?4.2 and 445?±?18 Bq kg^?1, respectively. The Barra de Valizas–Aguas Dulces region had the highest activity concentrations of ²²⁶Ra and ²³²Th. The annual effective dose equivalent for this region was higher than the mean worldwide value, whereas it is lower than the recommended values for public exposure.     

<Superscript>226</Superscript>Ra, <Superscript>232</Superscript>Th and <Superscript>40</Superscript>K activities in soils of Cuihua Mountain National Geological Park,China

Gamma activity from the naturally occurring radionuclides namely, ²²⁶Ra, ²³²Th, the primordial radionuclide ⁴⁰K was measured in the soil of Cuihua Mountain National Geological Park, China using γ-ray spectrometry technique. The mean activity of ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 27.2 ± 6.5, 43.9 ± 6.2 and 653.1 ± 127.6 Bq kg⁻¹, respectively. The concentrations of these radionuclides were compared with the typical world values and the average activities of Chinese soil. The radium equivalent activity, the air absorbed dose rate, the annual effective dose rate, and the external hazard index were evaluated and compared with the internationally approved values. All the soil samples have Ra_eq lower than the limit of 370 Bq kg⁻¹ and H _ex less than unity. The overall mean outdoor terrestrial gamma dose rate is 66.3 nGy h⁻¹ and the corresponding outdoor annual effective dose is 0.081 mSv.     

Radiological monitoring and statistical approach of primordial and anthropogenic radionuclides in surface soil of Mami-water site in the Western Cameroon

The study referred to measure activity concentrations of some primordial radionuclides and anthropogenic of ¹³⁷Cs in soil samples of Mami-water in the Menoua subdivision, Dschang employing gamma-ray spectrometry-based characterized Broad Energy Germanium (BE6350) detector and a comparison of radiological and safety impact parameters on human due to primordial radioactivity in soil with some internationally approved values. In addition, statistical analysis of primordial radionuclides of ²²⁶Ra, ²³²Th and ⁴⁰K was performed to evaluate the distribution and the interrelation of radionuclides. Samples were randomly collected from a depth of about 0 to 5 cm from the top surface layer. Each of the sampling points was considered as being overlaid with a grid and subdivided into cells. The observed radioactivity level of ²²⁶Ra, ²³²Th and ⁴⁰K in the investigated soil samples was compared with some published data available in some countries including Cameroon and observed varying within some reported data of radioactivity in soil from bauxite ore deposit. ²³⁵U and ¹³⁷Cs were found in very few samples with a very low average of activity concentrations. In the majority of the samples, the observed radiological safety parameters seem to be greater than the internationally approved values. Consequently, using bricks made of soil as building materials might lead to an increase in radiation risk for the population. Multivariate statistical analysis of activity concentrations of primordial radionuclides performed showed an asymmetrical distribution with more peaked than Gaussian distribution and relatively flatter distribution of radionuclides in soil. In addition, a good positive interrelation between ²²⁶Ra and ²³²Th was observed and a weak negative one observed between ⁴⁰K and ²²⁶Ra–²³²Th.     

Assessment of radiation hazards due to the concentration of natural radionuclides in the environment

A study of natural radionuclides and radon concentration of Hamirpur District of Himachal Pradesh, India is carried out using various methodologies. The activity concentration of the natural radionuclides viz. ²²⁶Ra, ²³²Th and ⁴⁰K is measured using high-resolution-based HPGe detector. Indoor radon measurements in the dwellings of Hamirpur district is carried out using LR-115 type II cellulose nitrate films in the bare mode. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K are 35.58, 54.95 and 580.58 Bq kg^?1, respectively. The annual average indoor radon value in the study area varies from 173.90 to 198.25 Bq m^?3, which is well within the recommended action level given by International Commission on Radiological Protection. The indoor radon values obtained in the present investigation are higher than the world average of 40 Bq m^?3. Radon concentration in water samples is measured using RAD7, an active radon detector. The annual effective dose for stomach and lung is determined from the measured value of radon concentration in water. To assess the radiation hazard of the natural radioactivity in all samples to the people, the radium equivalent activity, external hazard index, lifetime fatality risk, absorbed dose rate and total annual effective dose is estimated. The results signify that the studied area does not possess any radiation hazards due to the presence of natural radioactivity concentration.     

Radionuclides measurements and mineralogical studies on beach sands, East Rosetta Estuary, Egypt

Radiometric measurements were carried out for the beach sands from East Rosetta estuary to determine the activity concentrations of 238 U, 226 Ra, 232 Th, and 40 K, using a Hyper Pure Germanium spectrometer, to estimate the dose rates and radiation hazard indices. The average specific activities are 778.20 Bq/kg for 238 U; 646.89 Bq/kg for 226 Ra; 621.92 and 627.85 Bq/kg for the 222 Rn daughters 214 Pb and 214 Bi respectively. The average specific activity of 232 Th is 1510.25 Bq/kg, while the calculated specific activity for 40 K has an average of 8.41 Bq/kg. The average specific activity of 235 U is 38.61 Bq/kg. The average absorbed dose rate is 1211.36 nGy/h, 20 times higher than the estimated average global primordial radiation of 60 nGy/h and 6 times higher than that of the world range (10-200 nGy/h). The radium equivalent (Ra eq ) values are from 6 to 9 times the recommended value. The internal and external hazard indices (H int , H ex ) indicate that their values are from 6 to 11 times the permissible values of these indices. These higher values may be due to the presence of economic heavy minerals containing radionuclides as zircon and monazite as well as some trace minerals, thorite and uranothorite. The mineralogical study indicates the beach sands contain heavy minerals, zircon, monazite, rutile, ilmenite, leucoxene, magnetite and garnet. The average abundance of zircon is 0.175 wt% ranging from 0.125 wt% to 0.239 wt%, while it is 0.004wt% ranging from 0.001 wt% to 0.007 wt% for monazite. The average abundance is 0.087 wt% for rutile; 2.029 wt% for ilmenite; 1.084 wt% for magnetite; 0.384 wt% for leucoxene and 0.295 wt% for garnet.     

Assessment of natural radioactivity in aquifer medium bearing uranium ores in Koprubasi,Turkey

Koprubasi, located within Manisa Province near the Izmir, is the biggest uranium mine where uranium ores originate from Neogene aged altered sandstone and conglomerate layers. The main objective of this study is to determine the radiation hazard associated with radioactivity levels of uranium ores, and the rocks and sediments around Koprubasi. In this regard, measured activity levels of ²²⁶Ra, ²³²Th and ⁴⁰K were compared with world averages. The average activity levels of ²²⁶ Ra, ²³²Th and ⁴⁰K were measured to be 5369.75, 124.78 and 10.0 Bq/kg in uranium ores, 24.32, 52.94 and 623.38 Bq/kg in gneiss, 46.24, 45.13 and 762.26 Bq/kg in sandstone and conglomerate, 73.11, 43.15 and 810.65 Bq/kg in sediments, respectively. All samples have high ²²⁶Ra and ⁴⁰K levels according to world average level. As these sediments are used as construction materials and in agricultural activities within the study area, the radiation hazard are calculated by using dose rate (D), annual effective dose rate (He), radium equivalent activity (Ra_eq) and radiation hazard index (I_yr). All the samples have Ra_eq levels that are lower than the world average limit of 370 Bq/kg. On the other hand, D, He and I_yr values are higher than world average values. These results indicate that the uranium ores in the Koprubasi is the most important contributor to the natural radiation level. The radioactivity levels of sediments and rocks make them unsuitable for use as agricultural soil and as construction materials. Moreover, it is determined that shallow groundwater in sediments and deep groundwater in conglomerate rocks and also surface water sources in the Koprubasi have high ²²⁶Ra content. According to environmental radioactive baseline, some environmental protection study must be taken in Koprubasi uranium site and the environment.     

Determination of natural radioactivity levels in soil and travertine of the region of Tokat and Sivas,Turkey

In this study, the environmental radioactivity measurements for Tokat and Sivas provinces in the northeast of Turkey were performed. Using gamma ray spectrometry, the activity concentrations of natural radionuclides in soil and travertine samples (²³²Th, ²²⁶Ra, and ⁴⁰K) were determined. The annual effective dose equivalent, the absorbed doses rate in air, the radium equivalent, and the external hazard index were obtained from these activities. The activity concentrations vary from 9.09 to 17.04 Bq kg^?1 for ²³²Th, from 36.53 to 76.95 Bq kg^?1 for ²²⁶Ra, and from 216.56 to 576.59 Bq kg^?1 for ⁴⁰K in soil samples. The activity concentrations in travertines vary from 15.99 to 21.01 Bq kg^?1 for ²³²Th, from 19.89 to 67.71 Bq kg^?1 for ²²⁶Ra, and from 179.89 to 314.43 Bq kg^?1 for ⁴⁰K. The average dose rate in air for soil and travertine samples was 43.41 and 41.05 nGy h^?1 respectively. The obtained results are presented and compared with other studies, and the results of this study are lower than the international recommended value (55 nGy h^?1) given by UNSCEAR ( 2000). The results show that the region has a background radiation level within the natural limits.     

An analysis of naturally occurring radionuclides and <Superscript>137</Superscript>Cs in the soils of urban areas using gamma-ray spectrometry

This study of environmental radioactivity was carried out in the soils of an urban area. Naturally occurring gamma-emitting radionuclides and man-made ¹³⁷Cs were found in the soil profiles collected from four parks in the central Belgrade city area and the soil layer was examined every 10 cm and to a depth of 50 cm. Radioisotope activity concentrations (Bq kg^?1) in the samples of urban soil using the gamma-ray spectrometry method were in the range of 14–46 for ²³⁸U, 33–50 for ²²⁶Ra, 29–63 for ²¹⁰Pb, 1.2–3.4 for ²³⁵U, 28–50 for ²³²Th, 424–576 for ⁴⁰K and 0.7–35.8 for ¹³⁷Cs. Some of the basic physicochemical soil properties (pH, organic matter content, calcium-carbonate content, particle size distribution) were determined to investigate the impact on the vertical distribution of radionuclides. The results of this investigation showed that variations of activity concentration ratios of radionuclides that belong to the same (²³⁸U/²²⁶Ra) or different radioactive series (²³²Th/²²⁶Ra; ²³⁵U/²³⁸U), including ²¹⁰Pb/¹³⁷Cs ratios could well be explained by the properties of the soil. Alkaline pH reaction, the accumulation of organic matter in the uppermost and of carbonates in the deepest layers of urban soil had an effect on ²³⁸U/²²⁶Ra, and ²¹⁰Pb/¹³⁷Cs activity concentration ratio values, while ²³²Th/²²⁶Ra and partially ²³⁵U/²³⁸U ratios were associated with the particle sizes vertical distribution. A study of radionuclides in the samples of leaves of two deciduous tree species common for these parks was also conducted and ²¹⁰Pb and ⁴⁰K were found concentrated in leaves rather than other investigated radionuclides.     

Radiological hazard assessment for building materials incorporating phosphogypsum made using Eshidiya mine rock in Jordan

The mean activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in Eshidiya phosphogypsum samples were measured as 351.4 ± 23.4, 3.8 ± 0.3, and 120.7 ± 8.3 Bq kg^?1, respectively. The results show that the mean values of activity concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K are in the lower range of typical values reported for phosphogypsum samples collected worldwide. Radiological hazard indices such as the radium-equivalent activity (Ra_eq), the gamma index (I _γ ) alpha index (I _α ), the absorbed gamma dose rate (D _in), and the corresponding annual effective dose (E _in) were assessed for building materials for dwellings. The results of assessment exhibit that all phosphogypsum samples are higher than the recommended safe limit for building materials for dwellings, except for the radium-equivalent activity (Ra_eq). Overall assessment, it can be concluded that the possibility of using Eshidiya phosphogypsum in building materials in proportions lower than 100 % will be safe. The mixture of phosphogypsum with normal gypsum can dilute the concentrations of natural radionuclides allowing the use of the mixed building materials to be safe from a radiological point of view.     

Potential effect of natural radionuclides in riverbed sediments: a statistical approach based on granulometric and magnetic mineral differences

South India is one of the regions in the world that has the highest background radiation levels. In this region, river sediments are used in large quantities as building material. Therefore, the knowledge of the radionuclides distribution in such sediments is important for assessing their potential adverse effects on humans residing in buildings made of sediment material. For this goal, we focus on the determination of the natural radioactivity levels and magnetic properties in sediment samples collected from 33 locations along the southwestern Bharathapuzha river originating from the Anamalai hills. The sediment samples were subdivided into two categories according to particle size. It is observed that the average activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in sediment samples varied greatly with granulometric and geological differences. The average values of ²²⁶Ra, ²³²Th, and ⁴⁰K and its associated radiological hazard parameters for category II samples (particle size between 149 μm and 2 mm) were lower than category I sediment samples (bulk samples). Moreover, the average radionuclide activity concentrations (except for ⁴⁰K) and the calculated radiation hazard parameters are higher in the lowland region compared to the highland and the midland regions. The mass-specific magnetic susceptibility values ranged widely along the river, as well as between physiographic regions, e.g., average values for category I sediment samples were 950.2 × 10^?8, 351.1 × 10^?8 and 131.8 × 10^?8 m³ kg^?1 (for high-, mid- and lowland regions, respectively). Differences between physiographic regions and sediment fractions from both radioactivity determinations and magnetic parameters were analyzed with statistical tests and multivariate analysis, which showed the advantages of using both independent techniques.     

Natural and artificial radioactivity levels and hazards of soils in the Kücük Menderes Basin,Turkey

In this study, natural and artificial radionuclide activity concentrations in surface soils of Kücük Menderes Basin have been measured using gamma spectroscopy. The soil samples were collected from agricultural lands in the Kücük Menderes Basin in Turkey. The activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs in the soils were found to be range of 12.63 ± 2.28–72.51 ± 11.23, 11.45 ± 2.4–58.12 ± 4.76, 234.8 ± 14.85–1058.52 ± 24 Bq kg^?1 dw and 2.31 ± 0.18–7.75 ± 1.14 Bq kg^?1, respectively. The natural gamma radioactivity of the terrestrial radionuclides in soil samples and the gamma absorbed dose rate, the annual effective dose equivalent, the radium equivalent activity, the external hazard index, were calculated and compared with the international recommended values.     

Assessment of the radiological hazards of sand sediments collected from streams and streamlets of the uranium deposit areas in West Khasi Hills District,Meghalaya, India

Primordial radionuclides in sand sediments that are often used as constructing materials are one of the sources of radiation hazard in dwellings. Activity concentrations of the primordial radionuclides of ⁴⁰K, ²²⁶Ra and ²³²Th have been measured in sand sediments collected from streams and streamlets lying within and around the uranium mineralization deposit blocks of Kylleng-Pyndensohiong, Mawthabah Areas of West Khasi Hills District, Meghalaya, India. The technique of gamma-ray spectroscopy using a NaI(Tl) detector with a PC-based multi channel analyser was applied for determination of the activity concentrations. The activity of the sand sediments obtained in this study ranges from 95.3 to 1,088.8 Bq kg⁻¹ for ⁴⁰K; 38.3 to 784.1 Bq kg⁻¹ for ²²⁶Ra and 78.0 to 316.1 Bq kg⁻¹ for ²³²Th. Sand sediments from two sampling locations lying within the mineralization zone show highest concentrations of these radionuclides. The radiological hazards of the sand sediments were calculated using various models given in the literature. The radium equivalent activity was found to be higher than the accepted standard criterion value of 370 Bq kg⁻¹ and the values of external and internal hazard indices were also found to be higher than unity in these two sampling locations. Besides these two sampling locations, a sampling location lying at a nearby distance from the mineralization zone also exhibits hazard indices values greater than unity.     

Anomalous concentrations of radionuclides in the groundwater of Ede area,southwestern Nigeria: a direct impact of geology

An assessment of the groundwater in areas underlain by pegmatite in Ede, southwestern Nigeria was carried out to determine the concentration of Potassium-40 (⁴⁰K), Uranium-238 (²³⁸U) and Thorium-232 (²³²Th) radionuclides. In the earlier work, it was established that zircons in these pegmatites have suffered a high degree of metamictization that has enhanced continuous loss of some radionuclides since the time of emplacement of the pegmatite host rock to the present. The aim of this work is to determine whether or not there is corresponding increase in the concentration of radionuclides in groundwater in the study area. Fifteen groundwater samples were collected from both hand dug wells and boreholes in the area. Ten samples were from Ede town, two samples each from nearby communities of Iddo and Ekuro and one from Iwoye, where the bedrocks were not pegmatites. All the 15 samples were analyzed with the Sodium Iodide scintillator (NaI [Tl]) detector at the Centre for Energy Research and Development, Obafemi Awolowo University, Ile-Ife, Nigeria. The results showed varying concentrations of the radionuclides in the water samples. Activity concentrations of Potassium-40 (⁴⁰K) indicated an average value of 17.149 Bq/L for samples from Ede, 9.265 Bq/L for Iddo, 6.6 Bq/L for Ekuro, while Iwoye has a value of 21.21 Bq/L. The Uranium-238 (²³⁸U) series had an average value of 13.64 Bq/L for Ede, 13.49 Bq/L for Ekuro, 11.685 Bq/L for Iddo and 12.04 Bq/L for the lone sample from Iwoye. Thorium-232 (²³²Th) series had an average value of 11.182 Bq/L for Ede, while average values of 7.79 Bq/L and 9.025 Bq/L, respectively, were recorded for Iddo and Ekuro and 12.25 Bq/L for Iwoye. The annual effective dose level of ⁴⁰K is generally below the World Health Organization (WHO) recommended dosage of 0.1 mSv/y except for three locations, while those of ²³⁸U and ²³²Th are in excess of the standard values. The high radionuclides in the groundwater in the study area were not due to anthropogenic sources but directly due to geological processes which release the radioisotopes from rocks after weathering, continuous loss from metamict minerals and natural lateral mobility from regions of radionuclides’ release to other areas. There is thus the need to carry out systematic studies of the radionuclides concentrations on regional scale in the area which could lead to investigating on both short- and long-term health effects on organic species in these areas, and development of purification systems before utilizing water from the areas for domestic and industrial purposes.     

Assessment of lifetime cancer risk from natural radioactivity levels in Kadikoy and Uskudar District of Istanbul

The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K are measured in soil samples from various locations in the Kadikoy and Uskudar district of Istanbul (Turkey). The ²²⁶Ra activity concentrations range from 19.97 Bqkg^?1 to 50.80 Bqkg^?1 and average ²²⁶Ra concentration value 31.40 Bqkg^?1 was calculated. The ²³²Th activity concentrations range from 21.38 Bqkg^?1 to 52.61 Bqkg^?1 and average ²³²Th concentration value 34.44 Bqkg^?1 was calculated. The ⁴⁰K activity concentrations range from 464.06 Bqkg^?1 to 711.27 Bqkg^?1 and average ⁴⁰K concentration value 619.59 Bqkg^?1 was calculated. In addition, radium equivalent (Ra_eq), absorbed gamma dose rate (D), annual effective dose equivalent, (AEDE), excess lifetime cancer risk (ELCR) were calculated in this study. All of the calculations have been compared with both national and international standards and similar studies. As a result of this comparison, levels of natural radioactivity and radiological effects were slightly higher than the World average and Turkey.     

Natural radioactivity distribution and gamma radiation exposure of beach sands from Sithonia Peninsula

This study aims to evaluate the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, ²²⁸Th and ⁴⁰K along the beaches of Sithonia Peninsula which are adjacent to the rock-types of the Sithonia Plutonic Complex. These range from 6–673, 5–767, 5–1750, 6–1760 and 185–875 Bq/kg respectively. The (% wt.) heavy magnetic (HM) fraction (epidote, allanite, hornblende, biotite and garnet), the heavy non-magnetic (HNM) fraction (monazite, zircon, titanite and apatite) and the total heavy (TH) fraction, were correlated with the concentrations of the measured radionuclides in the bulk samples. The HNM fraction seems to control the activity concentrations of ²³⁸U in all samples, while the HM fraction, at least for the heavy mineral rich samples bearing high amounts of epidote crystals with allanite cores, controls their ²³²Th content. The measured radionuclides in beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parent rocks, in order to provide data on their enrichment or depletion. The annual effective dose varies from 0.013 to 0.688 mSv y^?1 for local people working on the beach, while for tourists the annual external effective dose ranges between 0.003 and 0.165 mSv y^?1.