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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.
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
3.
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
4.
P. Vesterbacka S. Klemola K. Salahel-Din M. Saman 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):441-448
An intercomparison of the methodology (alpha, beta and gamma spectrometry) used for 238U, 235U and 210Pb determination was carried out based on 38 sediment samples. The activity range of the samples varied from 10–700 Bq/kg
for 210Pb, 1–35 Bq/kg for 235U and 10–800 Bq/kg for 238U. Results obtained using the three methods were not statistically different at high activity levels, but agreement between
the results decreased at lower sample activity levels. For 210Pb, the smallest difference was found between alpha and gamma spectrometry. A good correlation between results from alpha
and gamma spectrometry was observed over the whole activity range. In beta spectrometry, the results were slightly higher
than those obtained by alpha or gamma spectrometry due to the impurity of 228Ra. In 238U analysis, good correspondence was observed between 238U determined by gamma and alpha spectrometry, particularly at higher 238U activity concentrations over 100 Bq/kg. In 235U analysis, attention needs to be paid to interference from 226Ra and its reduction. 相似文献
5.
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
6.
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
7.
M. Liezers O. T. FarmerIII M. L. Thomas 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(1):309-313
The measurement of fission product cesium isotopes 135Cs and 137Cs at low femtogram (fg) 10−15 levels in ground water by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) is reported. To eliminate the natural barium
isobaric interference on the cesium isotopes, in-line chromatographic separation of the cesium from barium was performed followed
by high sensitivity ICP-MS analysis. A high efficiency desolvating nebulizer system was employed to maximize ICP-MS sensitivity
~10 cps/fg. The three sigma detection limit for 135Cs was 2 fg/mL (0.1 μBq/mL) and for 137Cs 0.9 fg/mL (0.0027 Bq/mL) measured from the standard with analysis time of less than 30 min/sample. Cesium detection and
135/137 isotope ratio measurement at very low femtogram levels using this method in a spiked ground water matrix is also demonstrated. 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.
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
10.
Zidan Mohamed M. Houmani Amran Ab. Majid Shahidan Radiman Zaharudin Ahmad 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):271-277
226Ra is a member of the 238U natural decay series and is one of the most important isotope to be determined among the naturally occurring nuclides in
environmental samples. In order to evaluate the radiation dose from 226Ra, it is important to know its mobility in different types of soils. The aim of the present study is to quantify the influence
of physico-chemical soil properties on 226Ra adsorption. The distribution coefficients (K
d-value) of 226Ra in Selangor soil series samples were measured in one core, at three depth levels to evaluate the adsorbability of 226Ra. The soil samples were spiked with 226Ra tracer and the activities of 226Ra in the separated phase from batch sorption test were measured by a low background but high efficiency well-type HPGe detector.
Several physico-chemical soil properties were also characterised for each soil samples. Pearson’s correlation and stepwise
multiple regression test were applied at the 0.05 level of significance throughout all analysis to determine the relationships
and influences between distribution coefficients (K
d-value) of 226Ra with physicochemical soil properties for the Selangor soil series. The observed K
d value was in the range of 50.55–172.28 mL g−1 (mean: 93.20 ± 46.99 mL g−1). The regression showed that the highest positive correlations were observed for organic matter (OM) and cation exchange
capacity (CEC) (r = 0.96**, 0.81**, respectively) with K
d-values. The results indicate that the stepwise multiple regression model incorporating the soil’s OM and CEC accounts for
98% of the variability in distribution coefficients of 226Ra. 相似文献
11.
<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
12.
The activity concentrations of the Ra isotopes, 226Ra and 228Ra, as well as of 222Rn were measured in Austrian tap waters. Rn was extracted into a mineral oil cocktail not miscible with water and measured
by liquid scintillation counting using pulse-shape analysis for α/β-separation. Ra isotopes were co-precipitated with BaSO4 or concentrated by filtration through an element specific filter. EDTA solution was used to redissolve the precipitate as
well as to release the Ra from the filter. After mixing with a cocktail, the EDTA solution was measured by liquid scintillation
counting, too. From our results the effective ingestion doses for adults and 3 months old babies were calculated. 相似文献
13.
Özlem Selçuk Zorer Tekin Şahan 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):417-421
Gross α and gross β activities and 238U concentrations were determined in 18 surface water samples collected from Van Lake. The instrumentations used to count the
gross α and gross β activities and to determine the 238U concentrations were α/β counter of the multi-detector low background system (PIC-MPC-9604) and Inductively Coupled Plasma-Mass
Spectrometry (Thermo Scientific Element 2), respectively. Concentrations ranging from 0.001 to 0.021 Bq L−1 and from 0.111 to 2.794 Bq L−1 were observed for the gross α and β activities in surface waters, respectively. For all samples the gross β activities were
higher than the corresponding gross α activities. The results indicated that the gross α radioactive contamination in water
samples was lower than recommended values for the guideline of drinking waters and most of the gross β activities in water
samples were higher than those in the same procedure. The 238U concentrations ranged from 74.49 to 113.2 μg L−1 in surface waters. The obtained results have showed that 238U concentrations are higher than guideline values for uranium. 相似文献
14.
Effects of La3+ and Eu3+ on outward potassium channels (Kout+) in Vicia guard cells have been studied by patch clamping technique. Extracellular La3+ inhibited Kout+ currents with a half-inhibition concentration (IC50) of 81 μmol·L−1. Interestingly, intracellular La3+ activated Kout+ currents at a free concentration of 1.13 × 10−14 mol·L−1, and inhibited Kout+ currents at a free concentration of 5.86 × 10−14 mol·L−1. Extracellular Eu3+ also activated Kout+ currents at concentrations of 10 μmol·L−1 and 50 μmol·L−1, and inhibited Kout+ currents at concentrations of more than 1 mmol·L−1. The effects of La3+ and Eu3+ on Kout+ currents may contribute to regulation of the plant water status, which may be one of the mechanisms of the biological effect
of rare earth elements. 相似文献
15.
Baki B. Sadi Chunsheng Li Gary H. Kramer Cassandra L. Johnson Queenie Ko Edward P. C. Lai 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):415-425
A new radioanalytical method was developed for rapid determination of 226Ra in drinking water samples. The method is based on extraction and preconcentration of 226Ra from a water sample to an organic solvent using a dispersive liquid-liquid microextraction (DLLME) technique followed by
radiometric measurement using liquid scintillation counting. In DLLME for 226Ra, a mixture of an organic extractant (toluene doped with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone) and a disperser
solvent (acetonitrile) is rapidly injected into the water sample resulting in the formation of an emulsion. Within the emulsion,
226Ra reacts with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone and partitions into the fine droplets of toluene. The water/toluene
phases were separated by addition of acetonitrile as a de-emulsifier solvent. The toluene phase containing 226Ra was then measured by liquid scintillation counting. Several parameters were studied to optimize the extraction efficiency
of 226Ra, including water immiscible organic solvent, disperser and de-emulsifier solvent type and their volume, chelating ligands
for 226Ra and their concentrations, inorganic salt additive and its concentration, and equilibrium pH. With the optimized DLLME conditions,
the accuracy (expressed as relative bias, B
r
) and method repeatability (expressed as relative precision, S
B
) were determined by spiking 226Ra at the maximum acceptable concentration level (0.5 Bq L−1) according to the Guidelines for Canadian Drinking Water Quality. Accuracy and repeatability were found to be less than −5%
(B
r
) and less than 6% (S
B
), respectively, for both tap water and bottled natural spring water samples. The minimum detectable activity and sample turnaround
time for determination of 226Ra was 33 mBq L−1 and less than 3 h, respectively. The DLLME technique is selective for extraction of 226Ra from its decay progenies. 相似文献
16.
L. Popov G. Mihailova I. Hristova P. Dimitrova R. Tzibranski V. Avramov I. Naidenov B. Stoenelova 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):49-64
The method for the determination of 90Sr which employs sodium hydroxide for the separation of strontium from calcium was further improved introducing the use of
elevated temperatures. The results from 11-year study of background activity concentrations of 90Sr in different environmental objects in 100 km zone around Kozloduy Nuclear Power Plant (Bulgaria) are presented as an application
of the analytical method. The measured mean values are as follows: air precipitation − 0.0015±0.0009 Bq(m2.d), tap water − 0.0017±0.0012 Bq/L, soil − 1.90±1.26 Bq/kg, grass − 1.54±0.80 Bq/kg, milk − 0.023±0.012 Bq/L and for the Danube
river: water − 0.0046±0.0026 Bq/L, bottom sediments − 0.64±0.60 Bq/kg, algae − 1.99±1.56 Bq/kg. The calculated transfer coefficients
(soil-grass) are in the range of 0.33–0.84. Between 2 and 5 times reduction in actual background activities of 90Sr is observed compared to 1972–1974. 相似文献
17.
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
18.
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
19.
N. M. Antovic I. Antovic N. Svrkota 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):605-614
232Th activities in the South Adriatic Sea-water, surface sediment, mud with detritus, seagrass (Posidonia oceanica) samples, and the mullet (Mugilidae) species Mugil cephalus, as well as soil and sand from the Montenegrin Coast, were measured using the six-crystal spectrometer PRIPYAT-2M, which
has relatively high detection efficiency and a good sensitivity, and allows a short acquisition time, and measuring samples
of any shape, without preliminary preparation and calibration measurements for different sample geometries. An average 232Th activity concentration in surface soil layer is found to be 40.33 Bq kg−1, while in sand—4.7 Bq kg−1. The absorbed dose rate in air due to 232Th gamma radiation from surface soil layer ranged from 11.76 to 63.39 nGy h−1, with a mean of 24.06 nGy h−1. Corresponding average annual effective dose rate has been found to be 0.03 mSv y−1. The absorbed dose rates due to the thorium gamma radiation in air at 1 m above sand surface on the Montenegrin beaches have
been found to be from 0.41 to 9.08 nGy h−1, while annual effective dose rates ranged from 0.0005 to 0.011 mSv y−1. 232Th activity concentration in seawater ranged from 0.06 to 0.22 Bq L−1, as in the mullet (Mugil cephalus) whole individuals from 0.63 to 1.67 Bq kg−1. Annual intake of 232Th by human consumers of this fish species has been estimated to provide an effective dose of about 0.003 mSv y−1. 相似文献
20.
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