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1.
Mathematical equations governing the ratio of 210Bi/ 210Pb and 210Po/ 210Pb activities are used to explain the ingrowth of 210Bi and 210Po in environmental samples during post collection. Procedures are described for radiochemical separation of 210Pb, 210Bi, and 210Po in a state of radioactive disequilibrium and quantification by alpha- and beta-counting. Also, the special case is considered where 210Bi is in equilibrium with 210Pb, but both are in disequilibrium with 210Po. In this case, the activities of both 210Pb and 210Po are computed by measuring 210Po activity twice, using alpha-counting. 相似文献
2.
To determine the levels of 210Pb and 210Po in human tissues of people in Japan, various tissue samples were obtained at autopsy from the cadavers of 22 oncologic cases, mainly in Niigata Prefecture in northern Japan, from 1986 to 1988.Wet ashing, followed by electrochemical deposition and alpha spectrometry were used to separate and determine the 210Pb and 210Po present. Among the tissues analyzed, the highest concentrations of 210Pb and 210Po were observed in bone (sternum), liver, and kidneys. The total body burden of 210Pb and 210Po was found to be approximately 427 pCi and 514 pCi, respectively. This estimated 210Po value did not differ significantly from values found in populations in the U.S.A. and European countries. 相似文献
3.
A scheme of fractionation of 210Pb, 210Bi, 210Po forms present in air aerosols based on the combination of methods of radiochemical analysis and radiometric deteemination with leaching by different agents has been developed. The ratio between the 210Pb, 210Bi, 210Po present in the aerosol samples was determined experimentally. Carbonate of 210Pb, and 210Po and 210Bi forms connected with oxides prevai in the aerosol component of atmospheric air. 相似文献
4.
A determination procedure has been developed for 210Bi and 210Po in environmental samples and was applied for pine needles. Bismuth-210 and 210Po separated from the parent nuclide 210Pb as BiOCl precipitate were extracted simultaneously by TOPO/toluene containing PPO and POPOP. The separation of 210Bi and 210Po from 210Pb was almost satisfactory. The activity of 210Bi+ 210Po in the TOPO/toluene was measured periodically by liquid scintillation counting for about 20 days after separation. The time course of the decreasing pattern of the activity was determined by the initial activity ratio 210Po/ 210Bi. The decreasing pattern of the activity was compared with theoretical patterns, and best estimates for 210Po and 210Bi were obtained by non-linear least-squares fitting. The activities of 210Bi and 210Po were determined for one-year and two-year old pine needles fro the same pine tree, and weathering half-time and deposition rate of these nuclides was discussed. 相似文献
5.
Using as eluent a sequence of 3M HCl, 12M HCl, and 8M HNO 3, a mixture of 210Pb, 210Bi, and 210Po may be clearly separated on a column of Dowex 1×2−100 anion exchange resin. A Cherenkov count in H 2O and the variation in count rate with time confirm that the nuclides emerge in the order 210Pb→ 210Bi→ 210Po. If 12M HCl is replaced by 1.5M H 2SO 4/2.3 M Na 2SO 4, a clean separation also results, but recovery of 210Po becomes considerably more difficult. All three nuclides are readily detectable by liquid scintillation counting, with the
efficiency for 210Pb in the 60–70% range. The Cherenkov aqueous counting efficiency for 210Bi is ∼14–15%. 相似文献
6.
Displacement-extraction of tracer concentrations of 210Po in 1.0M (H, Na)NO 3 solutions has been studied by using copper dithizonate–CCl 4 solutions. Furthermore, based on the results of the displacement-extraction of polonium, a mixture of 210Po, 210Bi, and 210Pb of tracer concentrations in 1.0M (H, Na)NO 3 solutions could be satisfactorily separated with successive extractions by copper dithizonate–CCl 4 and dithizone–CCl 4 solutions in acidic conditions. 相似文献
7.
Transfer of 210Pb and 210Po from an uranium mine and mill to the environment was studied by measuring their concentrations in different stages of uranium extraction technology, in waste products from the mill and in environmental waters. A slightly modified radiochemical method was used for 210Po and 210Pb determination. 相似文献
8.
The concentrations of 210Po and 210Pb were determined in about 30 species of marine organisms collected mainly from the north-easterm region of Japan to know the levels and distributions of these radionuclides and to estimate their intake levels from marine foods. 210Po and 210Pb showed a wide range of concentration in species: 0.6–26 and 0.04–0.54 Bq/kg (wet wt) in fishes, 0.5–220 and 0.2–43 Bq/kg (wet wt) in molluscs, echinoderms and chordatas, and 2.8–4.3 and 0.4–1.3 Bq/kg (wet wt) in algae, respectively. Higher accumulation of 210Po relative to 210Pb was found in all of the samples analyzed. The intake levels of 210Po and 210Pb by marine foods consumption were roughly estimated to be 0.48–0.69 and 0.022–0.042 Bq/d per person, respectively, on the basis of the statistical data on the consumption of seafood and/or production rates of marine foods. 相似文献
9.
This research describes methods for the sequential determination of 210Pb and 210Po activity concentrations in Ca-rich ash samples collected from oil shale-fired power plants in Estonia. The procedure involves digestion of Ca-rich ash samples in a microwave digestion system, radiochemical separation of 210Pb and 210Po and their measurements. All samples, blanks and standards were measured by liquid scintillation counting (Quantulus 1220). The method was tested using IAEA (International Atomic Energy Agency) RGU-1 and IAEA-444 reference materials. Spectral calibration/peak identification which included the optimization of α/β discrimination system (pulse shape analyser), and recovery have been made by 209Po and 210Pb standard solutions. 相似文献
10.
A method for 210Po and 210Pb determination in water samples is described. The nuclides are concentrated, in presence of added 208Po and lead carrier, by evaporation. Then the polonium is plated electroless from the acidic solution on a copper planchet and measured by alpha spectrometry. 210Pb separation from the other isotopes is based on the solutility of PbSO 4 in citrate. 210Pb content is determined by measuring the activity of its daughter 210Bi. The critical steps in the isolation of lead have been examined and discussed. 相似文献
11.
Alpha-counting of filters used to sample large volumes of air provides a convenient way of determining atmospheric concentrations of 210Pb. Following decay of short-lived 222Rn and 220Rn progeny, alpha activity of the filters increases as 210Pb decays to 210Po. After transient equilibrium is reached at about 3 y, alpha activity diminishes with the 22.3 y halflife of 210Pb. The degree of equilibrium between 210Pb and 210Po can be calculated subsequent to sampling, and the average concentration of 210Pb in the air during the sampling period can be computed. Contributions to the total 210Pb from ambient short-lived radon progeny are small, typically 2–4%. Using high volume air samplers with collection rates of 1.1–1.7 m 3/min for 24 h periods, and using counting times of 2 h for 20 cm 2 filter sections, we measured alpha counts ranging from 0.0100±0.0050 to 0.200±0.0200 dps. Periodic measurements on 100 of these filters over a 4 y period yielded mean 210Pb levels with standard deviations less than ±15%. The method requires minimal sample preparation and can be used to determine past atmospheric 210Pb concentrations on filters stored for up to 20 y and more. 相似文献
12.
210Pb and 210Po in human hair have been measured to serve as an aid in order to estimate the dietary intake and body burden of these radionuclides of Japanese. The 210Po concentrations found in 83 hair samples were ranging from 4.0 to 59.3 mBq/g with a mean (median) value of 18.2±12.2 (14.9) mBq/g as compared to the 210Pb concentrations from 0.7 to 6.5 mBq/g with a mean (median) value of 2.3±1.1 (2.0) mBq/g. The 210Po/ 210Pb activity ratios (mean: 8.7±5.1, median: 7.1) were surprisingly higher compared with the available literature value of about 2. The high concentration of 210Po in human hair of Japanese may be due to the ingestion of animal protein mainly in the form of seafood. 相似文献
13.
Low-energy photon spectrometry with -spectrometry was used to determine the environmental concentrations of low-level actinides and other nuclides, especially 210Pb and 210Po. The isotopic ratio of 240Pu/ 239Pu was successfully determined by measuring L x-ray/-ray counting ratio. A reliable method has been developed for the determination of extremely low-level 237Np global fallout in environmental samples. The non-destructive determination by Ge-LEPS for natural 210Pb in various samples (tobacco leaves, commercially available tobacco, etc.) was also carried out with the determination of 210Po by -spectrometry using 209Po as a yield tracer. 相似文献
15.
A method for the separation of 210Pb, 210Bi and 210Po using spontaneous deposition has been developed. The 210Bi and 210Po are simultaneously removed by deposition onto nickel foil (copper and tin could also be used but less effectively) while the 210Po is separated from 210Bi, after dissolution of the nickel foil, by deposition onto silver foil. The effectiveness of each separation was evaluated by adding aliquot portions of each solution to a cocktail and counting with a liquid scintillation counter. Water was used as the medium to observe the Cherenkov count of the sample solution. 相似文献
16.
Measurement uncertainties in the determination of 210Pb and 210Po in Reference Material IAEA-300 (Baltic Sea Sediment) were evaluated. 210Pb and 210Po were separated from the matrix using an Sr resin column. The chemical yield of 210Pb was determined gravimetrically in PbSO 4 form. Precipitation was followed by beta proportional counting after 210Bi ingrowth. 210Po was determined by alpha spectrometry after its spontaneous deposition on a Cu planchet. The major source of uncertainty
was identified as the statistical counting uncertainty, which was also expected and is almost impossible to reduce without
extension of the time required for an analysis. The expanded uncertainties were determined as 7.4% and 12.2% for 210Pb and 210Po, respectively.
Received: 3 September 2002 Accepted: 3 December 2002
Acknowledgement This work was financially supported by Ministry of Education, Science and Sport, Republic of Slovenia (Project group PO-0106–0532).
Presented at CERMM-3, Central European Reference Materials and Measurements Conference: The function of reference materials
in the measurement process, May 30–June 1, 2002, Rogaška Slatina, Slovenia
Correspondence to P. Vreˇcek 相似文献
17.
The determination of 210Po in phosphoric acid reagent by alpha-ray spectrometry using extraction chromatographic resin is presented. The decontamination factors of interference elements were measured. It was observed that HCl, HNO 3, ascorbic acid, thioacetamide and Cu were free from 210Po but Pb contain small amounts of 210Po. 210Po in phosphoric acid samples was ranged from <8 to 2.4 Bq/l. The detection limit of 210Po in 50 ml of phosphoric acid is 8 mBq/l with a counting time of 1 day undercounting efficiency of 30%. 相似文献
18.
The concentrations of 89Sr, 90Sr, 210Pb and 210Po were measured in a series of rain samples collected at Fayetteville (36°N, 94°W), Arkansas, after the 14th Chinese test
of March 18, 1972, which occurred at Lop Nor (40°N, 90°E), China. Approximately concordant tropospheric residence times were
obtained from the 89Sr/ 90Sr and 210Po/ 210Pb ratios in rain. The 89Sr/ 90Sr ratios were also measured for the rain samples collected at Tokyo (36°N, 140°E), Japan, and at Ankara (40°N, 33°E), Turkey. 相似文献
19.
The paper deals with the determination of 210 Pb and 210 Po in mineral and biological environmental samples. 210 Pb and 210 Po were preconcentrated from filtered water samples by coprecipitation with iron(III) hydroxide at pH 9-10 using ammonia solution and the precipitate was dissolved with HCl and mineralized with H2O2. 210 Pb and 210 Po in soil or sediment, algae and mussel samples were sequentially leached out at 250 °C with HNO 3 +HF, HClO 4 and HCl. About 10-20% of the leaching solution was used for 210 Po determination which was carried out at 85-90 °C for 4 hours by suspending a silver disk in a HCl solution of pH 1.5 and containing some hydroxylamine hydrochloride and sodium citrate. No preliminary separation was required and essentially quantitative recoveries were obtained by using standard 209 Po tracer. The remains of the leaching solution were used for the determination of 210 Pb which was first separated by a BIO-RAD-AG 1-X4 resin column, then purified by using Na2S to precipitate as PbS and finally precipitated as PbSO 4 for source preparation. Starting from 3 g sediment (30 liter water), the lower limits of detection of the method were 0.73 Bq.kg -1 (0.078 mBq.l -1 ) for 210 Pb and 0.25 Bq.kg -1 (0.016 mBq.l -1 ) for 210 Po. The procedure has been checked with two certified samples supplied by the International Atomic Energy Agency (IAEA) and reliable results were obtained. Most of the analyzed samples were sediments, showing average yields of 84.2±5.2% for 210 Pb and 96.4±4.1% for 210 Po. 相似文献
20.
Ingrowth and decay of 210Po on air filters used for gross alpha-determination can lead to errors in estimation of long-lived airborne radioactivity. Interferences are present to some degree in all samples and change with time, making the gross alpha-technique quantitatively invalid. However, since the degree of equilibrium between 210Po and its parent 210Pb can be calculated at any time after filter collection, it should be possible to use the gross alpha-method to estimate past atmospheric concentrations of 210Pb. Measurements on filters after elapsed times of up to 15 years show that such determinations are feasible. 相似文献
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