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1.
The levels of radioactivity and heavy metals in soil, plant and groundwater samples collected from the area of the new campus of Taif University, Saudi Arabia, and its neighbouring areas have been determined. High-resolution gamma-ray spectroscopy was used for radioactivity measurements, and inductively coupled plasma atomic emission spectroscopy was used to determine the concentration of heavy metals. The means of 226Ra, 228Ra and 40K concentrations in water samples collected from four wells were found to be 0.13±0.03, 0.05±0.03 and 1.3±0.5 Bq l?1, respectively. The means of 238U, 226Ra, 228Ra (232Th for soil samples) and 40K concentrations in wild plant and soil samples were found to be 3.7±4.1, 8.8±11.6, 3.8±2.9 and 1025±685, and 8.6±3.4, 12.8±3.4, 16.6±7.1 and 618±82 Bq kg?1 dry weight (DW), respectively. The 137Cs of artificial origin was also detected in soil samples with a mean concentration of 3.8±2.2 Bq kg?1 DW. Evaluating the results, it can be concluded that the concentrations of 238U, 226Ra, 232Th and 40K in soil samples fall within the world average. Furthermore, 19 trace and major elements in groundwater samples and 22 elements in soil and plant samples were determined. The sampling locations of soil can be classified into three groups (relatively high, medium and low polluted) according to their calculated metal pollution index using the contents of trace and major elements. A cluster analysis of the contents of radioactivity and trace element contents in soil samples shows the presence of two main distinct clusters of sampling locations.  相似文献   

2.
An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides 226Ra, 232Th, 40K, and 137Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for 226Ra, 232Th, 40K, and 137Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg–1, respectively. The highest mean activity concentration for 226Ra was found to be 138?±?4 Bq kg–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg–1 for 232Th, and 14.2?±?1.9 Bq kg–1 for 137Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of 232Th, 40K, and 137Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to 226Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg–1, and 0.266, respectively.  相似文献   

3.
The analysis of gamma-emitting radionuclides in nature, i.e. 226Ra, 232Th, 40K and 137Cs, has been carried out in soil samples collected from Peshawar University Campus and surrounding areas using a high purity germanium detector coupled with a computer-based high-resolution multichannel analyser. The activity concentrations in soil ranged from 30.20±0.65 to 61.90±0.95, 50.10±0.54 to 102.80±1.04, 373.60±4.56 to 1082±11.38 and 9.50±0.11 to 46.60±0.42 Bq kg?1 for 226Ra, 232Th, 40K and 137Cs, with a mean value of 45±7.70, 67±12.50, 878±180 and 19±9.20 Bq kg?1, respectively. The radium equivalent activity, internal and external hazard indices have mean values of 203.40±29.40 Bq kg?1, 0.56 and 0.68, respectively. The mean values of outdoor and indoor absorbed dose rates in air and the annual effective dose equivalents were found to be 106.50 and 128 nGy h?1 and 0.19 and 0.54 mSv y?1, respectively. In the present study, 40K was the major radionuclide present in soil samples. The presence of 137Cs indicates that this area also received some fallout from the nuclear accident of the Chernobyl power plant in 1986. The activity concentrations of radionuclides found in soil samples during the current investigation were nominal. Therefore, they are not associated with any potential source of health hazard to the public.  相似文献   

4.
The activity concentration of natural (238U, 232Th, and 40K) and artificial (137Cs) radionuclides was determined in 50 samples (obtained from the same station) from various species of mushrooms and soil collected from the Middle Black Sea Region (Turkey). The activities of 238U, 232Th, 40K, and 137Cs were found as 84 ± 16, 45 ± 14, 570 ± 28, and 64 ± 6?Bq?kg–1 (dry weight), respectively, in the mushroom samples and as 51?±?6, 41?±?6, 201?±?11, and 44?±?4?Bq?kg–1, respectively, in the soil samples for the entire area of study. The results of all radionuclide activity measurements, except those of 238U and 232Th in the mushroom samples, are consistent with previous studies. In the soil samples, the mean values of 238U and 232Th are above the world mean, and the activity mean of 40K is below the world mean. Finally, the activity estimation was made with both the soil and mushroom samples for unmeasured points within the study area by using the ordinary kriging method. Radiological distribution maps were generated.  相似文献   

5.
The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km2 in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among 238U, 234Th, and 226Ra isotopes and low significant correlations between the concentrations of 238U-series and 232Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for 226Ra, 232Th, 40K, and 137Cs, respectively. The range of concentrations of 226Ra, 232Th, and 40K in water samples collected from five wells were<0.4–0.16,<0.4–0.13, and<0.15–1.62 Bq l?1, respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h?1. The Raeq activities of the sands are lower than the recommended maximum value of 370 Bq kg?1 criterion limit for building materials.  相似文献   

6.
This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176?±?5 nGy h?1. Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides 226Ra, 232Th and 40K are 110?±?3, 151?±?5 and 542?±?51 Bq kg?1, respectively.226Ra and 232Th concentrations were found to be three times the world average, while that of 40K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for 226Ra (215?±?6 Bq kg?1), 232Th (384?±?12 Bq kg?1) and 40K (1564?±?153 Bq kg?1). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg?1 and the unity value, respectively.  相似文献   

7.
The radiation survey of the ambient environment was conducted using two gamma detectors, and the measurement results were used in the computation of the mean external radiation dose rate, mean-weighted dose rate and annual effective dose, which are 144 nGy h?1, 0.891 mSv y?1 and 178 μSv, respectively. A high-purity germanium detector was used to determine the activity concentrations of 232Th, 226Ra and 40K in soil samples. The results of the gamma spectrometry of the soil samples show radioactivity concentration ranges from 19±1 to 405±13 Bq kg?1 with a mean value of 137±5 Bq kg?1 for 232Th, from 21±2 to 268±9 Bq kg?1with a mean value of 78±3 Bq kg?1 for 226Ra and from 23±9 to 1268±58 Bq kg?1 with a mean value of 207±13 Bq kg?1 for 40K. Radium equivalent activity (Raeq) and external hazard index (Hex) were 290 Bq kg?1 and 0.784, respectively, which were safe for the population. The mean lifetime dose and lifetime cancer risk for each person living in the area with average lifetime (70 y) were 12.46 mSv and 7.25×10?4 Sv year, respectively. The results were compared with values given in United Nations Scientific Committee on the Effects of Atomic Radiation 2000.  相似文献   

8.
The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among (238)U, (234)Th, and (226)Ra isotopes and low significant correlations between the concentrations of (238)U-series and (232)Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. The range of concentrations of (226)Ra,( 232)Th, and (40)K in water samples collected from five wells were<0.4-0.16,<0.4-0.13, and<0.15-1.62?Bq?l(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1?m above the ground surface for the sand samples was 19.4?nGy?h(-1). The Ra(eq) activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials.  相似文献   

9.
The results of activity concentration measurements of natural occurring radioactive nuclides 238U, 235U, 232Th, 226Ra, and 40K in surface soil samples collected in the area of cities Tuzla and Lukavac, northeast region of Bosnia and Herzegovina were presented. Soil sampling was conducted at the localities that are situated in the vicinity of industrial zones of these cities. The measured activity was in the range from (8?±?4) to (95?±?28) Bq kg–1 for 238U, from (0.41?±?0.06) to (4.6?±?0.7) Bq kg–1 for 235U, from (7?±?1) to (66?±?7) Bq kg–1 for 232Th, from (6?±?1) to (55?±?6) Bq kg–1 for 226Ra, and from (83?±?12) to (546?±?55) Bq kg–1 for 40K. In order to evaluate the radiological hazard of the natural radioactivity for people living near industrial zones, the absorbed dose rate, the annual effective dose and the radium equivalent activity have been calculated and compared with the internationally approved values.  相似文献   

10.
A survey was conducted to evaluate levels of indoor radon and gamma doses in 42 primary schools located in Batman, southeastern Anatolia, Turkey. Indoor radon measurements were carried out using CR-39 solid-state nuclear track detector-based radon dosimeters. The overall mean annual 222Rn activity in the surveyed area was found to be 49 Bq m?3 (equivalent to an annual effective dose of 0.25 mSv). However, in one of the districts (Besiri) the maximum radon value turned out to be 307 Bq m?3. The estimated annual effective doses are less than the recommended action level (3–10 mSv). It is found that the radon concentration decreases with increasing floor number. The concentrations of natural and artificial radioisotopes were determined using gamma-ray spectroscopy for soil samples collected in close vicinity of the studied schools. The mean gamma activity concentrations in the soil samples were 31, 25, 329 and 12 Bq kg?1 for 226Ra, 232Th, 40K and 137Cs, respectively. The radiological parameters such as the absorbed dose rate in air and the annual effective dose equivalent were calculated. These radiological parameters were evaluated and compared with the internationally recommended values.  相似文献   

11.
In Rechna Doab, samples of the most common vegetation, perennial grass Desmostachya bipinnata (dab), were collected along with soil samples from 29 sites. Natural radioactivity of 226Ra, 232Th/228Ac and 40K was measured by using high purity germanium-based gamma ray spectrometer. Activity concentration levels of 226Ra, 232Th/228Ac and 40K in soil were found to be 46.8±6.2 (36.0–57.6), 61.4±5.9 (48.2–73.2) and 644.8±73.9 (537.7–868.4) Bq kg?1 (dry mass), respectively, and those in vegetation were 2.74±1.70 (1.00–6.39), 2.24±0.59 (1.56–2.61) and 172.72±113.37 (53.14–469.24) Bq kg?1 (dry mass), respectively. The measured values of the activity concentration in vegetation are comparable with some other international data. Calculated soil to vegetation transfer factors of 226Ra, 228Ac and 40K were 0.06±0.03 (0.02–0.14), 0.04±0.01 (0.03–0.04) and 0.26±0.16 (0.09–0.69). The mean outdoor absorbed dose rate in air for the area under study was determined as 8.22 nGy h?1 and the mean indoor absorbed dose rate in air was 11.52 nGy h?1. The total annual effective dose to the general public from the vegetation was found to be (0.02–0.16) mSv, which is below the recommended limit value of 1 mSv y?1 for the general public. The dab vegetation under study was found to be radiologically safe for the population and environment.  相似文献   

12.
Studies of the natural γ-emitting radionuclides in different types of cements manufactured by different companies in Egypt (e.g. Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan Ltd.) have been done to determine their natural levels of radioactivity using a high-purity germanium detector (HPGe). Knowledge of radioactivity present in cement materials enables one to assess any possible radiological risks to human health. The results show that the highest mean values of 226Ra and 232Th activity are 234.01±20.12 and 46.56±4.65 Bq kg?1, respectively, measured in cement sample ‘Iron’ from Helwan company (HI). The corresponding value of 40K is 333.53±26.68 Bq kg?1 measured in cement sample ‘Karnak’ from Helwan company (HK). For 137Cs, this value is 3.27±0.31 Bq kg?1 measured in cement sample (HI). The average concentrations of measured radionuclides in the different cement samples are 72.21±6.39, 24.98±2.24, 134.49±10.45, and 0.58±0.08 Bq kg?1 for 226Ra, 232Th, 40K, and 137Cs, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries. Radium equivalent (Raeq) activities and different hazard indices were calculated to assess the radiation hazard. Iron HI cement sample shows a higher Raeq activity of 311.91±31.10 Bq kg?1. Calculations of absorbed doses in nGy h?1 show that the Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan company have higher activities than the permissible level (80 nGy h?1). On the basis of the external hazard index (H ex), Raeq activities, and annual effective dose rates for organs (H organ), the natural radioactivity of cement samples is not greater than the recommended values in the established standards and hence safe for use in building constructions and therefore for inhabitants.  相似文献   

13.
Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides 226Ra, 232Th and 40K were measured by using γ-ray spectrometry. The mean activity concentrations of 226Ra, 232Th and 40K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg?1 for 226Ra, 83±5, 71±7 and 162±23 Bq kg?1 for 232Th and 513±10, 493±20 and 681±28 Bq kg?1 for 40K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.  相似文献   

14.
Research of the effect of salinity on the fate of radionuclides has been focused on seas or estuarine systems while there is almost no information on marine environments with a salinity higher than that of sea water. The hypersaline Bardawil lagoon is a concentration basin, with evaporation exceeding precipitation. This study presents the characteristics of some environmental factors including salinity and their influence on the distribution of natural and artificial radionuclides in different compartments of the lagoon. The concentrations of 238U, 234Th, 228Ra and 137Cs in sediments show some degree of dependency on the water's salinity. Migration of these radionuclides in the lagoon's sediments must take place from high salinity to low-salinity regions. Cluster analysis revealed the data structure for sediment by separating 137Cs and 40K from 232Th, 226Ra, and 234Th and for sand by separating 40K from the other radioisotopes.  相似文献   

15.
The objective of this study is to evaluate natural and artificial radioactivity levels in 18 different samples of medicinal herbs from Serbian market. The activity concentrations of (238)U, (232)Th, (40)K, and (137)Cs were measured using gamma spectroscopy system with a high-purity germanium detector. The activity concentrations of (238)U, (232)Th, (40)K, and (137)Cs were found to be in a range of 0.6-8.2, 1.7-15.1, 126-1243.7, and 0.3-8.8 Bq/kg, respectively. The annual whole body doses from ingestion of (137)Cs and natural radionuclides for an adult person who consumed herbal tea from these medicinal herbs were found to be 2.5-469.9 nSv for (137)Cs, 0.7-9.7 nSv for (238)U, 0.3-2.8 nSv for (232)Th, and 1026.0-10,132.0 nSv for (40)K. These doses are not hazardous to public health. The obtained results were compared with correspondent studies conducted worldwide.  相似文献   

16.
The current study presents the results of the activity of radionuclides in spa waters, and evaluates their radiological influences on the population consuming these waters in the Central and Eastern Black Sea regions of Turkey. Since these waters are used for therapy and consumption purposes unconsciously, their radiological impact on the people was computed by taking into consideration the annual intake through ingestion of 226Ra, 232Th, 40K, 137Cs and 222Rn. The mean activities were estimated to be 11.35 for gross alpha, 6.23 for gross beta, 2.96 for 226Ra, 0.42 for 232Th, 0.069 for 137Cs, 0.19 for 40K, and 267 Bq L–1 for 222Rn, respectively. The estimated effective doses from spa water were found to be 49.77 µSv a–1 (226Ra), 5.95 µSv a–1 (232Th), 0.07 µSv a–1 (137Cs), 0.83 µSv a–1 (40K) and 56.03 µSv a–1 (222Rn). These values were evaluated and compared with related verified values from literature. Also, physico-chemical characterizations of spa water samples considered in the current study were investigated. This study would be useful for consumers and official authorities for the assessment of radiation exposure risk due to usage of the considered spa waters.  相似文献   

17.
The activity concentrations of both natural (238U and 232Th chains and 40K) and anthropogenic (137Cs) radionuclides down along the soil profile have been determined in soil samples collected from inland and coastal areas of the La Plata River, located in the Northeastern region of the Province of Buenos Aires, Argentina. These studies were complemented with 57Fe Mössbauer spectroscopy characterization, pH, texture and organic carbon content measurements. From Mössbauer results, the sample compositions differ from one area to the other. Spectra from both soil samples are dominated by the Fe3+? paramagnetic signal. For soil samples from the coastal area, the ??-Fe2O3 contribution is lower, Fe3O4 was not detected, and the relative areas of each spectral contribution are nearly constant with depth. For samples from the inland area, the Fe3+? paramagnetic fraction increases up to 82%, mainly at the expense of the magnetically ordered phase. The main observed activity originates from the decay of 40K (540?C750 Bq/kg), followed by 238U (60?C92 Bq/kg) and 232Th (37?C46 Bq/kg) chains. The activity of 235U was in all the cases lower than the detection limit (LD?=?0.02 Bq/kg). The only determined anthropogenic nuclide was 137Cs, arising from the fallout of the Southern Hemisphere nuclear weapon tests. Three of the observed differences in the depth distributions can be described by the dispersion-convection model. A correlation between the natural nuclide activities and the Mössbauer relative fractions was found, whereas no correlation was found between the 137Cs profile and the relative fraction of Fe3O4 or with other iron species.  相似文献   

18.
The primordial radionuclides activity concentrations (226Ra, 40K and 232Th) are measured in some granite samples in this study. The collected granite materials are analyzed with NaI(Tl) gamma-ray spectrometry. The specific activity of 226Ra, 232Th and 40K values are in range 2.60?±?0.10 to 178.9?±?0.6?Bq?kg?1, 1.46?±?0.10 to 162.50?±?0.75?Bq?kg?1 and 19.8?±?0.3 to 579.7?±?2.8?Bq?kg?1 respectively. The radium’s equivalent activity, annual effective dose, absorbed dose rate, hazard index, radioactivity level index, activity utilization’s index and exposure rate are calculated for determination of radiological risk. The concentration of 226Ra (in the 71.4% of samples), 232Th (in the 71.4% of samples) and 40K (in the 14.3% of samples) in the granite samples are higher than average radioactivity concentrations of this radio-isotopes defined by ICRP (35.0, 30.0 and 400.0?Bq?kg?1, respectively).  相似文献   

19.
Twenty-two medicinal herb samples, each representing a distinct species, were collected from Turkish markets and measured by the gamma spectrometric method. The activity concentration of 226Ra in medicinal herbs was found in the range of minimum detectable activity (MDA) and 15.1?±?2.2?Bqkg?1. The activity concentration of 232Th ranged from MDA values to 3.5?±?0.8?Bqkg?1. The activity concentration of 40K varied between 50.0?±?16.8 and 1311.5?±?57.3?Bqkg?1. All 137Cs activity concentrations of medicinal herbs were found to have lower than MDA values. The bone surface dose, lower large intestine and colon doses were found to be 182.9, 18.8 and 18.7?µSvy?1, respectively. The highest committed effective dose originated from the annual ingestion of 1?kg medicinal herb was calculated notably low as 9.0?µSv. The cancer risk of ingestion of medicinal herbs was found to be small enough to be neglected. The selected Turkish medicinal herbs are considered safe for human consumption.  相似文献   

20.
《Radiation measurements》2009,44(1):116-121
238U, 232Th and 40K concentrations in 72 soil samples from two major fault systems (North and East Anatolian Active Fault Sytems) in Turkey have been studied. However, terrestrial gamma radiation dose originated by natural radionuclides in soil was measured and compared with other measurements in literature for different countries. This extensive survey regarding U, Th and K radionuclide and terrestrial gamma dose measurement was carried out by means of NaI(TI) gamma spectroscopic system and a dose rate meter, respectively. The mean concentration of 238U, 232Th and 40K in soil samples in NAFS is higher than determined in EAFS. The measured and calculated mean gamma dose rates in two fault systems are found to be higher than 57 nGyh−1.  相似文献   

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