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1.
Zal U’yun Wan Mahmood Che Abd Rahim Mohamed Mei Wo Yii Zaharudin Ahmad Kamaruzzaman Ishak Abdul Kadir Ishak 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):107-113
Inventories and fluxes of 210Pb, 228Ra and 226Ra were determined in sediment cores collected at nine stations covering of the southern South China Sea and Malacca Straits
with the thickness of water column between 42 and 83 m depth. The inventories of 210Pb, 228Ra and 226Ra were calculated range from 0.15–2.55 Bq cm−2, 0.05–0.40 Bq cm−2 and 6.83–83.63 Bq cm−2, meanwhile the fluxes ranged from 0.005–0.079 Bq cm−2 yr−1, 0.009–0.048 Bq cm−2 yr−1 and 0.003–0.037 Bq cm−2 yr−1, respectively. The results show that the highest inventories and fluxes for 210Pb, 228Ra and 226Ra were found at station WC 01 and EC 05. Because there are additional sources of 210Pb, 228Ra and 226Ra, where water transport will brings more dissolved isotopes, influence of the transportation and deposition of suspended
particles, fast rate of regeneration and greater production of those radionuclides and others. 相似文献
2.
The natural radioactivity in phosphate fertilizers used in central Italy has been measured by alpha and gamma spectrometry. The results show that the specific activities of 238U, 234U and 235U ranged within interval from < 0.5 to 2628.8, from < 0.5 to 2826.3 and from < 0.9 to 138.0 Bq kg− 1 respectively and those of 210Pb and 210Po ranged within interval from < 15.0 to 401.5 and < 0.5 to 351.6 Bq kg− 1 respectively. The 228Th, 230Th and 232Th concentrations found by alpha spectrometry ranged from < 0.5 to 50.2, from 0.9 to 2727.2 and from < 0.5 to 60.8 Bq kg− 1 respectively. 226Ra and 228Ra activity concentrations ranged from < 14.3 to 290.9 and from < 2.9 to 24.9 respectively. 40K specific activities ranged from 39.2 to 8263.7 Bq kg− 1. A very good correlation exists between the activity concentrations found by alpha spectrometry and those found by gamma spectrometry. 相似文献
3.
S. Pommé E. García-Toraño G. Sibbens S. Richter R. Wellum A. Stolarz A. Alonso 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(1):207-210
High-resolution alpha-particle spectrometry was performed on three uranium materials enriched in 235U. Besides the 235U peaks, separate peaks belonging to impurity traces of 234U could be quantified. Relying on the isotopic composition of the uranium, as determined by mass spectrometry, the ratio of
the half-lives of 238U and 235U was determined via the activity ratio of 234U and 235U in the materials. As an intermediate link, the 234U/238U half-life ratio was taken from published mass spectrometric analyses of ‘secular equilibrium’ uranium material. The resulting
half-life ratio T
1/2(238U)/T
1/2(235U) = 6.351±0.031 is in agreement with the commonly adopted half-life values determined by Jaffey et al. 相似文献
4.
Dimitrios C. Xarchoulakos Konstantina Kehagia Nikolaos Kallithrakas-Kontos Constantinos Potiriadis 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(2):285-292
For the first time, a radiological study for the dissolved 238U, 234U, 210Pb and 210Po was held in major Greek rivers across the country. 234U/238U activity ratios are above one in all samples and 210Po/210Pb activity ratios are respectively below the unit indicating the disequilibrium in the samples. Quite satisfactory correlations were observed among 234U and 238U as well as among 210Po and 210Pb values. Uranium isotopes were separated by ion exchange and electroplated on stainless steel plates. 210Po was spontaneously deposited on nickel plates, while 210Pb was indirectly determined through the ingrowth of 210Po. The sources were measured by a-spectrometry. 相似文献
5.
Claudia Landstetter Christian Katzlberger 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(2):467-471
Screening measurements for 3H, 226Ra, 222Rn and 238U in ground water were performed within a ground- and drinking water project in Austria. The aim of this project is to get
an overview of the distribution of natural radionuclide activity concentration levels in ground water bodies. In some cases
this water is used for drinking water abstraction. In this paper methods and results of the screening measurements are presented.
Regions with high activity concentrations were identified and in these regions further investigation for 228Ra, 210Pb and 210Po will be conducted. 相似文献
6.
Eduardo H. Montoya Pablo A. Mendoza Patricia S. Bedregal Oscar R. Baltuano Isaac M. Cohen 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(1):175-178
A method that combines the use of non-destructive neutron activation analysis and high-resolution α spectrometry has been
developed for determination of the activities of 234U and 238U in geological samples of low uranium content. The 238U content is determined by k0-based neutron activation analysis, whereas the 234U/238U relationship is measured by α spectrometry after isolation and electrodeposition of the uranium extracted from a lixiviation
with 6 M HCl. The main advantage of the method is the simplicity of the chemical operations, including the fact that the steps
destined to assure similar chemical state for the tracer and the uranium species present in the sample are not necessary.
The method was applied to soil samples from sites of the North Peru Coast. Uranium concentration range 3–40 mg/kg and the
isotopic composition correspond to natural uranium, with about 10% uncertainty. 相似文献
7.
Marine sediment cores were collected from two stations at East Malaysia coastal waters on June 2004. Activity concentrations
of 210Pb in sediment core were ranged from 11 Bqkg−1 to 84 Bqkg−1 dry wt. for SR 01 and 4 Bqkg−1 to 66 Bqkg−1 dry wt. for SB 03. Meanwhile, activity concentrations of 226Ra in sediment core were varied significantly depending on the sampling location of SR 01 and SB 03 with ranged 17–26 Bqkg−1 dry wt. and 8–11 Bqkg−1 dry wt., respectively. The activity ratios of 210Pb/226Ra were no significantly different at all sampling stations with an average of 1.78. Refer to the entire results; the activities
of 210Pb and 226Ra were higher at station SR 01 than station SB 03, but contrast with ratio of 210Pb/226Ra. The reasons of different 210Pb and 226Ra activity concentration and distribution of their ratios were strictly related to their half lives, environment origin,
potential sources and behavior. 相似文献
8.
Activity concentrations of 238U, 235U and 234U were determined in different sources of drinking water at the Obuasi gold mines and its surrounding areas in Ghana. Water
samples collected from the mines and its surrounding areas were analyzed using direct gamma-ray spectrometry and neutron activation
analysis. The 234U/238U and 235U/238U ratios were calculated and the mean values range from 1.27 to 1.38 and from 0.044 to 0.045 respectively. The average 234U/238U ratio was from 1.27 for groundwater to 1.38 for treated water, demonstrating the lack of equilibrium. The average 235U/238U activity ratio is 0.045, indicating that only natural uranium was detected in the samples investigated. 相似文献
9.
Wu Men Fenfen Wang Guangshan Liu 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):189-195
The activities of 224Ra in the East China Sea (ECS) were measured by the Mn-fiber adsorption—emanation method. The horizontal and vertical distributions
of 224Ra in the ECS in summer and winter were studied. The ranges of 224Ra activities were < lowest limit of detection (LLD)–5.88 Bq/m3 in summer with an average of 0.85 Bq/m3, and < LLD-7.50 Bq/m3 in winter with an average of 0.72 Bq/m3. And the distributions of 224Ra in the surface water were similar in these two seasons, decreasing rapidly with the increasing distance from the coast.
The high 224Ra area was located within 30–100 km offshore and the lowest activities appeared in the Kuroshio Current. The vertical distributions
of 224Ra showed two different characteristics. The horizontal and vertical eddy diffusion coefficients calculated by the one-dimensional
state model of 224Ra were (7.1–88.9) × 106cm2/s and 2.18–163 cm2/s, respectively. The upwelling rates off Zhejiang Province were calculated from 224Ra vertical distribution, which varied from 8.4 × 10−3cm/s to 13.3 × 10−3cm/s in summer and 16.3 × 10−3cm/s to 16.8 × 10−3cm/s in winter. 相似文献
10.
Andrea D. Choiniere Rosara F. Payne Charles M. Knaack Steven C. Smith Sue B. Clark 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(3):1013-1017
Soil materials used were collected in the early 1970s at Idaho National Laboratory near the Subsurface Disposal Area (SDA).
Samples from a depth of 0–4 and 4–8 cm at two different sites located on the northeast corner of the SDA perimeter were analyzed.
The concentration of 234U, 235U, 236U, and 238U in soil digests were measured by mass spectrometry. Uranium isotopic composition of the soil at the two sample sites and
depths is compared to previously measured concentrations of 238Pu, 239Pu, 240Pu, 241Pu, and 241Am. Implications for remediation of contaminated soils surrounding the SDA are discussed. 相似文献
11.
Wu Men Guang Shan Liu Yi Pu Huang 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):65-72
228Ra levels in the Yellow Sea and East China Sea were determined using the emanation method. The seawater radium was concentrated
using an Mn-fiber and the 224Ra ingrowth was measured after about half a year when the initial 224Ra in the sample would have decayed. The 224Ra activity in the sample was evaluated using the decay dynamics relationship between parent 228Ra and daughter 228Th. The concentration and distribution feature of 228Ra in the Yellow Sea and East China Sea were studied and the 228Ra concentrations in the surface seawater of the Yellow Sea and the East China Sea were in the range 0.09–15.0 Bq/m3 with an average of 6.84 Bq/m3 during the summer cruise, and in the range 0.09–16.9 Bq/m3 with an average of 6.37 Bq/m3 during the winter cruise. The 228Ra distribution in the northern Yellow Sea was different from the southern Yellow Sea and East China Sea. The highest 228Ra activity of surface water was located in the middle of the northern Yellow Sea, but for the southern Yellow Sea and East
China Sea, it decreased with increasing distance from China continent. 相似文献
12.
J. J. LaBrecque P. R. Cordoves M. A. Cordoves K. Perez D. Palacios J. A. Alfonso 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):669-674
This work presents the results of 137Cs, 40K, 232Th and 238U concentration (Bq kg−1) values in coastal marine sediments collected from 38 sites along the coastline of the island of Margarita, Venezuela. The
purpose was to determine baseline values for these radionuclides in surface marine sediments and to detect if there were any
anomalously high concentration values. Only three of the 38 sediments analyzed had measurable values above the detection limit
of 0.9 Bq kg−1 for 137Cs and the highest only being 1.4 Bq kg−1. While, the concentration (Bq kg−1) ranges for the primordial radionuclides, 40K, 232Th and 238U were as follows: 12.2–211.7, <1.5–9.8 and <4.4–20.7, respectively. These concentration ranges for the primordial radionuclides
can be considered as baseline values for surface marine sediments for areas that are considered not polluted by man or contaminated
by nature. Finally, the concentration range of 137Cs can also be employed as baseline values, which only seem to have been the result of the atmospheric testing of nuclear
weapons in the past. 相似文献
13.
Mei-Wo Yii Zal U’yun Wan Mahmood 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(3):819-833
This study with sampling expeditions of marine sediment, seawater and biota were performed at 30 stations within Malaysian
Exclusive Economic Zone (EEZ). A total of >400 samples were collected to determine the activity concentration of anthropogenic
radionuclides (239+240Pu, 137Cs) and their activity ratio (239+240Pu/137Cs) in sediments, seawater and biota. The purpose of this study was to determine the concentration levels for these radionuclides
and to evaluate any occurrence of radioactive contamination. Sediment cores were obtained using multicorer device, while water
samples via co-precipitation techniques and biota was purchased from local fishermen. The activity concentrations of 239+240Pu in sediment, seawater and biota were ranged 0.21–0.45 Bq/kg dry wt., 2.33–7.95 mBq/m3 and <0.008 Bq/kg fresh wt., respectively. Meanwhile, the values of 137Cs were ranged <1.00–2.71 Bq/kg dry wt. in sediment, 3.40–5.89 Bq/m3 in seawater and <0.05–0.41 Bq/kg fresh wt. in biota, respectively. Activity ratios of 239+240Pu to 137Cs obtained seem to confirm that these artificial radioactivities were mainly due to global nuclear fallout. 相似文献
14.
Ejaz ur Rehman Riffat Naheed Shakeel ur Rehman Munir Ahmed 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(2):333-336
The precision in measurement of trace level uranium isotopic ratio, i.e., 236U/238U or 234U/238U, on single Faraday detector with narrow dynamic range is very hard to achieve. this is mainly due to the narrow dynamic
range of a single detector systems. A significant improvement in mass spectrometric determination of 236U/238U ratio has been achieved by employing an alternate method using a single Faraday detector of narrow dynamic range. The method
makes use of the precise measurements of the 236U/234U ratio, 234U/235U ratio and 235U/238U ratio, which are used to calculate the 236U/238U ratio using the equation 236U/238U=236U/234U×234U/235U×235U/238U. Despite the fact that correlation of the data tends to increase the uncertainty in the result, our results show a significant
improvement, i.e., more than 8 times better precision in measuring the 236U/238U ratio with this method (σ=3.98×10−08) as compared to direct measurement of 236U/238U (σ=3.104×10−07). The method widens the applicability of the single collector system with narrow dynamic range and it will potentially be
helpful to improve the precision in the case of the static multi-collector system also. The objective of the present study
was to compare the results of the same sample analyzed with the present alternate method and the direct method for precision. 相似文献
15.
Radioactive Contamination of Lichens and Mosses Collected in South Shetlands and Antarctic Peninsula
J. W. Mietelski P. Gaca M. A. Olech 《Journal of Radioanalytical and Nuclear Chemistry》2000,245(3):527-537
Samples belonging to two species of lichen and one of moss collected on the Antarctic seashore (King George Island, Deception, Antarctic Peninsula) were analysed for gamma-emitters using HPGe gamma-spectrometry, and for alpha-emitters using alpha-spectrometry with silicon detectors. Observed 137Cs activities show large variations: from 4.1±0.4 to 74±3 Bq/kg. Total activity of 210Pb changed from <2 to 125±35 Bq/kg. The 2391240Pu activity ranged from 0.07±0.02 to 2.95±0.16 Bq/kg. The activity of 238Pu ranged from <0.02 to 0.64±0.04 Bq/kg. Maximum 238U and 234U activity was 7 Bq/kg, respectively, and 0.3 Bq/kg for 235U, whereas minimum activities were below 0.5 Bq/kg for 234U and 238U and about 0.02 Bq/kg for 235U. The 235U to 238U activity ratio for most of the samples was natural. Thorium activities were about two times lower than those for uranium. The activities of 147Sm ranged from 0.014±0.002 to 1.0±0.2 Bq/kg. One sample had relatively high activity of 241Am: 3.38±0.11 Bq/kg, another did not exceeded 1 Bq/kg. Observed activity ratios confirmed differences between mosses and lichen accumulation properties for radionuclides. Lichens are more selective for plutonium accumulation. Some radiocesium and probably also americium can be leached from them. 相似文献
16.
K. M. Rajashekara Y. Narayana S. A. Narasimha Pramod Shetty V. Prakash 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):137-140
The concentrations of 226Ra, 210Po and 210Pb have been measured, by high efficiency 5″ × 5″ NaI(Tl) gamma ray spectrometer and chemical deposition method, in surface
water samples from major rivers Kali, Sharavathi and Netravathi of coastal Karnataka. Measurements of 226Ra, 210Po and 210Pb in surface water from these rivers are important because the river water is main source of potable water in this region
due to inadequate supply of treated water. The mean activity of 226Ra, 210Po and 210Pb in the surface water of the river Kali was found to be 5.13 mBq L−1, 1.28 and 1.37 Bq L−1, for Sharavathi River the mean activity was found to be 3.37 mBq L−1, 1.30 and 1.44 Bq L−1. In Netravathi River the mean activity of 226Ra, 210Po and 210Pb was found to be 3.30 mBq L−1, 1.00 and 1.20 Bq L−1. From the measured concentration of 226Ra, 210Po and 210Pb, the Effective dose to the population of the region was computed. The results of these systematic studies are presented
and discussed in the paper. 相似文献
17.
Yong Yi Peng Zhou Guangshan Liu 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):157-162
The atmospheric deposition fluxes of 7Be, 210Pb and 210Po at Xiamen were measured. The samples were collected from March 2004 to April 2005 and the sampling period was one month.
The 7Be and 210Pb activity were measured using HPGe γ-spectrometer after concentration using Fe(OH)3 co-precipitation method. The 210Po was counted with an α-spectrometer after the sample was digested and spontaneous plated onto a silver planchet. At Xiamen,
the atmospheric deposition fluxes of 7Be varied between 0.11 and 2.93 Bq·m−2·d−1 and the average was 1.64 Bq·m−2·d−1; 210Pb fluxes varied between 0.04 and 0.85 Bq·m−2·d−1, and the average was 0.51 Bq·m−2·d−1; 210Po fluxes varied between 0.002 and 0.133 Bq·m−2·d−1, and the average was 0.061 Bq·m−2·d−1. There were positive correlations between the deposition fluxes of 7Be, 210Pb or 210Po and the amount of precipitation. The residence time of aerosols varied between 6.0 and 54.0 days with a mean of 27.1 days,
which were calculated by 210Po/210Pb fluxes ratios. 相似文献
18.
A. T. Abdul Rahman A. T. Ramli 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(3):653-657
A survey was carried out to determine terrestrial gammaradiation dose rates, the concentration level of 238U and 232Th and α and β activities for the surface soil in Ulu Tiram, Malaysia A 125 measurements were performed using a NaI(T1) gamma-ray
detector with crystal size of 1″ × 1″ on 15 soil samples collected from the site area about 102 km2
238U and 232Th concentrations were determined in soils by using hyper pure germanium (HPGe) gamma-ray spectrometry. The activity of α
and β from the surface soil was counted by using alpha beta counting system. The average value of 238U and 232Th concentrations in soil samples collected are 3.63±0.39 ppm within the range of 1.74±0.20 to 4.58±0.48 and 43.00±2.31 ppm
within the range of 10.68±0.76 to 82 10±4.01 ppm, respectively. The average estimate of α and β activity in soil samples collected
are 0.65±0.09 Bqg−1 and 0.68±0.08 Bqg−1, respectively. The average of terrestrial gamma-radiation dose rates measured in Ulu Tiram was found to be 200 nGy h−1, within the range of 96 to 409 nGy h−1. The population weighted outdoor annual effective dose was 1.2 mSv. 相似文献
19.
D. Desideri M. A. Meli C. Roselli L. Feduzi 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(2):591-600
In various samples of Mytilus galloprovincialis, 210Po was determined by alpha-spectrometry while Mn, Fe, Ni, Cu, Zn, Cd, Sn, Hg and Pb by energy dispersive, polarised X-ray
fluorescence spectrometry (EDPXRF). The mussels of different sizes were taken from 7 sites in the central Adriatic Sea along
the Marche coastal region during the four seasons of the year. 210Po activity concentration ranged between 57 and 343 Bq·kg−1 dry weight. The concentration ranges of heavy metals (μg·g−1 dry weight) were as follows: Mn: 72.9–83.1; Fe: 45.1–754; Ni: 1.3–7.6; Cu: 17.9–156; Zn: 60.9–189; Cd: 0.6–1.0; Sn: 0.6–3.9;
Hg always <0.5; Pb: 2.0–9.0. The data obtained depend upon the site and the period of the sampling and they are also compared
with those obtained by other authors for the same organism in the Mediterranean and other Italian seas. 相似文献
20.
The analysis of 226Ra in natural waters can be tedious and time-consuming. For the determination and differentiation of activities of 226Ra and 222Rn in drinking water by γ-ray spectrometry a simple and fast method is presented. Activities of 226Ra > 0.5 Bq L−1 can be determined according to stabilization of the sample without further procedures. For a more sensitive detection sample
volumes of up to 5 litres are applicable by a rapid precipitation procedure without large expenditure. Further laborious enrichment
methods are not necessary. Thus, detection limits of 0.1 Bq L−1 can be obtained when using sample volumes of 5 litres. Therefore the method is suitable for the monitoring of radioactivity
in drinking water samples in accordance with the legal guidance of the European Union. 相似文献