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1.
<Superscript>226</Superscript>Ra and <Superscript>228</Superscript>Ra determination in environmental samples by alpha-particle spectrometry 总被引:1,自引:1,他引:0
J. L. Aguado J. P. Bolivar R. García-Tenorio 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):191-199
A complete methodology for 226Ra and 228Ra determination by alpha-particle spectrometry in environmental samples is being applied in our laboratory using 225Ra as an isotopic tracer. This methodology can be considered highly suitable for the determination of these nuclides when
very low absolute limits of detection need to be achieved. The 226Ra determination can be performed at any time after the isolation of the radium isotopes from the analyzed samples while the
228Ra determination needs to be carried out at least six months later through the measurement of one of its grand-daughters.
The method has been validated by its application to samples with known concentrations of these Ra nuclides, and by comparison
with other radiometric methods. 相似文献
2.
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
3.
R. Kandlbinder V. Geißler R. Schupfner O. Wolfbeis B. Zinka 《Journal of Radioanalytical and Nuclear Chemistry》2009,280(1):113-119
The adsorption of Cs on clayey materials such as bentonite and Na-montmorillonite was studied in various electrolytic conditions
(concentration and composition), various solid to liquid ratios and various pH conditions. The results obtained for these
different conditions were modeled considering an exchange model associated to the surface complexation concept. Then, the
same approach was considered to model the sorption of Rb, which have the same chemical behavior than Cs. Experiments were
carried out for various electrolyte, pH, and Rb concentrations. The stoichiometries corresponding to the sorption of Rb on
bentonite and montmorillonite were then deduced from the experimental results. 相似文献
4.
L. I. Tsikritzis 《Journal of Radioanalytical and Nuclear Chemistry》2005,264(3):651-656
Summary The distribution and origin of 40K, 226Ra, 228Ra and 137Cs has been investigated in trees, mosses and lichens in the basin of the West Macedonia Lignite Centre. In tree leaves 137Cs is negligible, while the 226Ra and 228Ra concentrations are affected by the fly ash particles. Concerning 226Ra and 228Ra values of mosses and lichens, which are systematically larger than those of unpolluted areas, the application of chemometrics proved that they originate mainly from the lignite fly ash. 相似文献
5.
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
6.
Robert Kandlbinder Robert Schupfner Otto S. Wolfbeis 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(1):69-73
The determination of 228Ra by means of γ-spectrometry, in material containing significant quantities of 40K and Ca2+ such as bone ash results in increased values of counting uncertainty and lower limit of detection (LLD) because of a significant
contribution from the Compton continuum of 40K. However, 40K is widely removed from bone ash if 228Ra is coprecipitated with barium sulfate. As a result, the counting uncertainty and LLD are significantly reduced. A method
is presented for determination of very low activity concentrations of 228Ra. Impurities introduced by precipitation are negligible when applying high resolution γ-spectrometry. 相似文献
7.
A. Amekudzie O. Adukpo J. Annkah A. Faanu G. Emi-Reynolds 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(3):795-800
As part of monitoring the exposure of the Ghanaian public to natural radioactivity, radioactivity concentrations in titanium
enamel frits use for coating, spraying and decorating steel bowls were investigated. Samples collected from Ghana Utensil
Manufacturing Company in Ghana were analyzed using γ-ray spectrometry with a high purity germanium detector. The samples were
found to contain an average absorbed dose rate of 509.38 nGy h−1, while an average annual effective dose was calculated to be 2.50 mSv. 相似文献
8.
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
9.
N. M. Antovic V. Popovic I. Antovic N. Svrkota P. Vukotic 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):81-88
A coincidence method for measuring 137Cs, 40K, 226Ra and 232Th decay products activity in soil, vegetation and fish samples, was applied to the six-crystal gamma-coincidence spectrometer
PRIPYAT-2M. In this way, some problems appeared in simultaneous measurement of 137Cs, 226Ra and 232Th by NaI(Tl) detectors and the PRIPYAT-2M spectrometer were solved. The obtained results were agreeable with the HPGe spectrometer
ones. 相似文献
10.
John Thompson Nie Luo Charlie Entenmann G. H. Miley Mitchell R. Swartz 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):753-761
Radioactive decay rates are to a large extent believed to be independent of the chemical environment. This is the physics
basis implicitly assumed in applications such as radioisotope dating. While this statement is a good approximation for most
radioactive decays, there are cases where a slight variation of 0.5% or more can be observed, as in the electron capture type
of decay. There are renewed interests in possible decay-rate changes with external parameters such as temperature, with controversy
as to the phenomenon’s authenticity. In this paper, we study the variation of radioactivity counts that significantly change (up to 50% or more) with temperature. We carefully studied the characteristics of the change and
found that the presence of a gaseous decay daughter can pose a serious challenge to a bona fide account of the intrinsic nuclear decay rate. After a careful solution to rate equations of the relevant isotopes under our
experimental conditions, we found that most of the radioactivity change could be accounted for by the diffusion and loss of
gaseous daughters under the heat, without a supposed change in the intrinsic nuclear decay rate. We hence demonstrate that
an accurate determination of the decay constant has to consider the possible diffusion of volatile components in the decay
chain. This is especially important in cases involving significant temperature change. 相似文献
11.
Matthias J. Brunnermeier Stefanie A. K. Schmied Robert Schupfner 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1285-1290
The period of date of death of an elephant can be assessed by analyzing four different radionuclides, 14C, 90Sr, 228Th and 232Th in its ivory. These nuclides are supposed to have variing concentrations at different parts of a tusk. The reason is the
procedure of growth which takes place at the butt-site of a tusk. Therefore the site of sampling could have a big influence
on the assessed date of death. However, to find out if the position of sampling is important a complete tusk was analyzed
regarding the distribution of these nuclides. Results show that the concentration activity of 14C and 228Th varies in different parts of a tusk. The activity concentration of 90Sr is very similar in all analyzed parts. The conclusion is that sampling at the butt of a tusk is recommended for age assessment. 相似文献
12.
C. H. R. Saueia B. P. Mazzilli M. H. T. Taddei 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(2):201-204
The phosphate rocks used for the production of phosphate fertilizers present in their composition radionuclides of the U and
Th series. During the chemical attack, the radionuclides are distributed to final products and phosphogypsum. A sequential
radiochemical procedure was implemented to determine the content of radionuclides alpha emitters in samples of fertilizers
and phosphogypsum produced in Brazil. The results obtained show that the levels of radioactivity present in the fertilizers
are of the same order of magnitude on those found in the phosphogypsum, reaching values up to 1158 and 457 Bq kg−1, for the U and Th series, respectively. 相似文献
13.
W. Zhang K. Ungar J. Chen N. St-Amant B. L. Tracy 《Journal of Radioanalytical and Nuclear Chemistry》2009,280(3):561-567
A quantitative method to determine the activity concentration of 226Ra in soil samples was established using high performance environmental gamma-ray spectrometry. In this method, a semi-empirical
calibration procedure was developed for full energy peak efficiency calculation utilizing the elemental composition of the
soil sample. Aatami software was used to deconvolute the 235U and 226Ra doublet at 185.7 keV and 186.2 keV, respectively, and to fit the baseline of the soil gamma-spectrum for the determination
of 226Ra activity. The results indicated that the Aatami doublet deconvolution procedure provides a rapid and accurate analysis
of a complicated spectrum in comparison with other cumbersome spectral interference correction methods. The study also compared
the results with those obtained by radon progeny (214Pb, or 214Bi) measurements and found that the deconvolution method provided a more accurate 226Ra activity as it is independent of the error caused by radon diffusion. This error can be quite large since the amount of
escaped radon gas through the sample container walls and sealing cannot be accurately quantified. 相似文献
14.
D. Larivière D. K. Brownell V. N. Epov R. J. Cornett R. D. Evans 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(2):337-344
Three protocols (Method I: ion chromatography (IC) and extraction chromatography (EC), Method II: precipitation followed by
IC, and Method III: adsorption onto MnO2 followed by IC-EC) were investigated to determine their applicability for the separation and pre-concentration of 226Ra in sediments. 226Ra recoveries, measured using the isotope dilution method with 228Ra as yield tracer, and the removal of spectral and non-spectral interferences were evaluated. The formation of polyatomic
interferences at m/z = 226 from elements found in the matrix of sediments was also investigated to assess the level of separation required. Methods
I and III were found to be the most effective with respect to recoveries and interference removal. The efficiency of a rapid
microwave based protocol for the complete digestion of 1 g of sediment is also described. The method was tested and 226Ra concentrations in the millibecquerel range (fg) were determined in a standard reference material and sediment cores collected
from Lake Baikal. 相似文献
15.
R. Periáñez A. Absi M. Villa H. P. Moreno G. Manjón 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(2):293-299
The Odiel and Tinto rivers, southwest Spain, form a fully mixed estuary. An industrial area that includes a complex dedicated
to the production of phosphate fertilizers is located by the Odiel River. This complex released phosphogypsum wastes directly
to the Odiel River and also disposed them on open air piles located by the Tinto River. Due to new EU regulations, wastes
are not directly released to the Odiel from 1998 on, although they are still disposed on the open air piles. The behavior
of 226Ra in a system like this estuary is complex, since radionuclides are affected by tidal actions and interactions with sediments
through adsorption/desorption reactions and erosion/deposition processes. A numerical 2D depth-averaged model of the estuary
has been developed, including processes mentioned above. It has been applied to reproduce experimental data measured after
a release from the industrial complex in the Odiel River and after an accidental release in the Tinto River from the gypsum
piles. The model has also been applied to simulate the self-cleaning process observed in the estuary after the direct releases
from the fertilizer complex were stopped. 相似文献
16.
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
17.
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
18.
Tsuey-Lin Tsai Chun-Chih Lin Tsung-Yuan Wang Hwa-Jou Wei Lee-Chung Men 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(1):145-154
A rapid, accurate and less labor intensive approach to determining 226Ra in environmental samples was examined; this utilized quadrupole-based inductively coupled plasma mass spectrometry (ICP-QMS).
The procedure used chemical separation by ion exchange chromatography to remove most of the matrices after coprecipitation
with BaSO4. The average chemical recovery of the NIST SRM preparation method ranged from 60.5 to 85.9% using 133Ba as internal tracer by gamma counting. This technique was capable of completing a 226Ra measurement within 3 min. It did not require an in-growth period to allow radon and its progeny to achieve secular equilibrium
with the parent 226Ra as is needed for liquid scintillation analyzer (LSA). The method detection limits for the determination of 226Ra in geothermal water and sediment samples were 0.02 mBq L−1 (0.558 fg L−1) and 0.10 Bq kg−1 (2.79 fg g−1), respectively. The results obtained with various natural samples and the suitability of the method when applied to various
environmental matrices such as geothermal water and sediment are discussed. When ICP-QMS was compared to double-focusing magnetic
sector field inductively coupled plasma mass spectrometry (ICP-SFMS), good agreement was obtained with a correlation coefficient,
r
2 = 0.982. 相似文献
19.
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