首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 156 毫秒
1.
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.  相似文献   

2.
The natural radioactivity levels and magnetic measurements in sediment samples of Bharathapuzha river for the first time have been determined. Bottom sediments from 33 locations were collected to determine 226Ra, 232Th and 40K using a HPGe detector based on the high-resolution gamma spectrometry system, and magnetic susceptibility by using Bartington MS2 magnetic susceptibility meter. The calculated activity concentrations of 226Ra, 232Th and 40K have been found to vary from 21.21 to 66.03 Bq kg?1, 33.49 to 93.10 Bq kg?1 and 232.25 to 899.66 Bq kg?1, respectively. The results have been compared with worldwide recommended values and also with radioactivity measurements in river sediments of India and other parts of the world. The air-absorbed dose rate, indoor and outdoor annual effective dose rates and radium equivalent activity are calculated with an aim to access the radiation hazards arising due to the use of these materials in the construction of buildings and their mean values obtained are 74.83 nGy h?1, 367.08 μSv y?1, 91.77 μSv y?1 and 157.09 Bq kg?1, respectively. The mass-specific magnetic susceptibility values ranged widely from 35.4 to 2,160.5 × 10?8 m3 kg?1 and compared with other rivers in South India. Multivariate statistical analyses were performed to describe the magnetic and radioactivity relevance of the different groups of samples. The data obtained in the present study may be useful for radiological and magnetic mapping of the study area in the future.  相似文献   

3.
In this study, radioactivity measurements in the environment of Akhisar, Gölmarmara, Gördes and Sindirgi regions in Western Turkey were investigated in order to evaluate the implications of any excess radioactivity in the environment of geological formation. The radioactivity concentrations of 40K, 238U and 232Th radionuclides in the soil samples were measured by a NaI(Tl) gamma spectrometer system, and the radium activity concentrations in the water samples were also analyzed by an ZnS(Ag) alpha counter by the collector chamber method. The radioactivity of 40K, 238U and 232Th in soils ranged 2.80–2,347.77, 9.90–256.19 and 9.66–106.53 Bq kg?1, respectively. The activity of 226Ra in the water samples ranged from 0.03 Bq L?1 (0.89pCi/L) to 0.80 Bq L?1 (21.58pCi/L). In addition, the external terrestrial gamma dose rate in air (nGy h?1), annual effective dose rate (mSv year?1) and radium equivalent activity (Bq kg?1) were calculated and compared with international standard values.  相似文献   

4.
Oil mineral leases (30, 58 and 61) in Delta and River States are the major oil blocks in the oil and gas rich Niger Delta region of Nigeria that is characterized by environmental degradation from oil and gas activities. This research work presents an analytical approach on natural radioactivity assessment in soil and sediment in 15 oil fields of these OMLs. Concentrations of natural radionuclides (226Ra, 232Th and 40K) were determined using gamma spectroscopy. The mean activity concentration of 226Ra, 232Th and 40K for OML30 is 40.2 ± 5.1, 29.9 ± 4.2 and 361.5 ± 20.0 Bq kg?1, respectively; the corresponding values obtained for OML58 is 20.9 ± 2.8, 19.4 ± 2.5 and 260.0 ± 14.1 Bq kg?1, respectively. While the mean activity concentration of 226Ra, 232Th and 40K for OML61 is 29.3 ± 3.5, 21.6 ± 2.6 and 262.1 ± 14.6 Bq kg?1, respectively. These values obtained show enhanced NORMs, but are well within the world range and values reported in some regions and countries of the world, and are slightly above control values, values obtained in Southwestern region of Nigeria and some countries reported average values. The study also examined some radiation hazard indices, the mean values obtained are 86.6 ± 9.3 Bq kg?1, 0.6 Bq kg?1, 40.8 ηGy h?1, 0.05 μSv y?1, 0.2 and 0.3 for radium equivalent activity (Raeq), representative level index (Iγ), absorbed dose rates (D), annual effective dose rates (E ff dose), external hazard index (H ex) and internal hazard index (H in), respectively. These calculated hazard indices to estimate the potential radiological health risk in soil and sediment are well below their permissible limits. The soil and sediments from the study area provide no excessive exposures for the inhabitants and can be used as construction materials without posing any radiological threat or harm to the public users. However, oil-field workers and host community residents are cautioned against excess exposure to avoid future accumulative dose of these radiations from sludge and sediment of this area.  相似文献   

5.
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.  相似文献   

6.
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.  相似文献   

7.
The main focus of this study was to assess radiation exposure to human and non-human biota due to natural radionuclides in soil of the Serbian capital. For the first time, ERICA tool was employed for calculation of gamma dose rates to non-human biota in this area. In analyzed soils, the mean values of 226Ra, 232Th and 40K specific activities were found to be 35, 43 and 490 Bq kg?1, respectively. The distribution of analyzed natural radionuclides in soils was discussed in respect to its statistically significant correlations with sand, silt, clay, carbonates, cation exchange capacity and pH value. The annual outdoor effective dose rates to the population varied from 48 to 98 μSv, and the total dose rates to terrestrial biota, calculated by ERICA tool, varied from 9.84?×?10?2 μGy h?1 (for tree) to 5.54?×?10+0 μGy h?1 (for lichen and bryophytes). The results obtained could serve as a baseline data for the assessment of possible anthropogenic enhancement of the total dose rate to human and non-human biota of the study area.  相似文献   

8.
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 (Raeq), 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.  相似文献   

9.
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 (Raeq), normative value (NRN), outdoor radium equivalent (Raeq-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 RaFZ 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.  相似文献   

10.
Radon, thoron, and their progeny are largest contributors to the radiation dose received by human beings present in the natural environment. The indoor radon depends upon many factors such as building materials, meteorology, ventilation, and occupant’s behavior. This paper presents the measurements of indoor radon, thoron, and their progeny in four villages in rural area of district Kanshiram Nagar (Kasganj) in the state of Uttar Pradesh in Northern India. The concentration of indoor radon and thoron varies from 10.32 to 72.24 and 11.61 to 84.49 Bq m?3 with a geometric mean (GM) of 29.49 and 31.20 Bq m?3, respectively. The concentration of radon and thoron daughters was found to vary from 1.11 to 7.80 and 0.31 to 2.28 mWL, respectively. The annual exposure due to radon and thoron mainly vary from 0.05 to 0.30 WLM. The preliminary results (i.e., bare mode exposure of the LR-115 detectors fixed on cards) of this study have been separately published and compared this recent data with those results.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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 (Raeq), 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 (Raeq). 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.  相似文献   

14.
Tailings resulted from sulphuric acid leaching process of uranium from sedimentary rocks contain high concentrations of 226Ra and its daughters, the most important of which is 222Rn. Movement of radon gas out of the tailings is strongly influenced by the physicochemical characteristics of these tailings especially their radium content and the grain size. So, the tailing samples were size fractionated into four sizes (>?250, 250–125, 125–74 and <?74 µm). The natural radioactivity was investigated using hyper-pure germanium detector and solid-state nuclear track detectors (CR-39) for bulk size and after size fractionation. The activity concentrations of different radionuclides in size-fractionated tailing samples have been shown to be strongly dependent on the size of the particles. In the range of >?250 and <?74 µm, the activity concentrations of 230Th, 226Ra, 214Pb, 214Bi, 210Pb, 232Th and 40K increased throughout with decreasing particle size, while that of 238U, 234U and 235U have an opposite effect. The results revealed an inverse relationship between the radon exhalation rate and size fractionation. Also, the results showed a good correlation between radium activity concentration and radon mass exhalation rate.  相似文献   

15.
Based on γ-radiation dose rate and radon concentration measurements and 238U, 232Th, 226Ra, and 40K radionuclide testing, this study identifies the radioactive anomalies of stone coal-bearing strata in East China and evaluates the natural radioactivity levels in the air, solid, water and plant media in the typical area of the regional stone coal-bearing layers. The stone coal-bearing strata in East China occur in the lower Cambrian system along the margin of the Yangtze block; additionally, the radioactive anomaly area is sporadically distributed in the stone coal-bearing layers. The background values of 238U, 232Th, 226Ra, and 40K are higher in the stone coal-bearing areas, and the spatial distribution of these natural radionuclides shows significant variability. 238U and 226Ra clearly accumulate in the coal, coal gangue and soil and are the main sources of the environmental radiation in coal mines. The γ-radiation shows a higher background value in the stone coal-bearing area, and this radioactive pollution cannot be ignored. Typically, the effective dose of γ-radiation exceeds the limit value of 5 mSv/a, and the total α and total β concentrations of the groundwater are 10–30 times the limit value at some points. The residents near the mining area are subjected to a higher radiation dose, and the groundwater, building materials, and plants have been contaminated by the radioactive pollution sporadically through time. It is necessary to strengthen the monitoring work of radioactive environments and to take appropriate control measures.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
Concentration of natural radionuclides in three major staple food crops cultivated around a fertilizer plant in Onne, Rivers State Nigeria and the cultivated soil samples were determined using gamma spectroscopy operated on a Canberra vertical high purity 3″ × 3″ NaI(TI) detector. The average activity concentration of 238U, 232Th and 40K was determined, for cassava flour (U 19.3 ± 5.0, Th 11.4 ± 3.3, K 426.9 ± 33.8) Bq kg?1, for yam flour (U 6.3 ± 1.8, Th 8.4 ± 2.6, K 227.0.9 ± 27.3) Bq kg?1 while for cocoyam flour (U 7.5 ± 2.7, Th 7.1 ± 2.3, K 195.8 ± 25.83) Bq kg?1. The mean activity concentration for soil samples is 18.7 ± 3.7 Bq kg?1, 18.0 ± 3.8 Bq kg?1 and 308.4 ± 22.4 Bq kg?1 for 238U, 232Th and 40K, respectively. These values obtained show enhanced 40K concentration which is attributed to the effluent discharge from a fertilizer plant and its applications to farmlands, but 238U, 232Th values are well within the global average and values reported in some regions and countries of the world. Radiation hazard indices obtained to estimate potential radiological health risk in both foodstuffs and soil samples are well below their permissible limit as set by UNSCEAR [Sources and effects of ionizing radiation (Report to the General Assembly), 2000]. The rate of radionuclides transfer from soil to crops was moderate with mean transfer factors of 232Th < 238U < 40K.  相似文献   

19.
Levels of naturally occurring radioactivity in sediment samples of Beni Haroun dam have been investigated. The activity concentrations of 238U and 232Th decay chains and 40K primordial radionuclide have been measured using high-resolution HPGe detector. Activity concentrations of 226Ra, 232Th, and 40K radionuclides were found in the ranges 9–66, 14–37, and 177–288 Bq/kg with the mean values 24.67, 25.98, and 208.10 Bq/kg, respectively. Radiological hazard parameters were estimated based on the activity concentrations for 226Ra, 232Th, and 40K to find out any radiation hazard associated with the sediments. Correlation studies between pairs of radionuclides were performed and discussed, and the obtained results are compared with international recommended values.  相似文献   

20.
Due to the widespread use of granites as building and ornamental materials, measurements of natural radioactivity for a total 27 selected samples of commercial granites used in Egypt were carried out by using a high pure germanium detector. The activity concentrations of 226Ra, 232Th and 40K of commercial granites ranged from 25 to 356, 5 to 161, and 100 to 1,796?(Bq?kg?1), respectively. The concentrations of these radionuclides are compared with the international recommended values. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the absorbed dose rate, the effective dose rate, and the hazard index have been calculated. The radium equivalent activity Raeq varied from 41 to 669?(Bq?kg?1) which exceeds the permitted value (370?Bq?kg?1) and the internal hazard index H in varied from 0.2 to 2.8 which is higher than 1. The absorbed dose rate due to the natural radioactivity in the samples under investigation ranged from 19 to 310?(nGy?h?1). The total effective dose rates per person indoors were determined to be 0.09 to 1.5?(mSv?year?1).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号