Radiochemical determination of210Po and210Pb in water

A method for²¹⁰Po and²¹⁰Pb determination in water samples is described. The nuclides are concentrated, in presence of added²⁰⁸Po 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 PbSO₄ in citrate.²¹⁰Pb content is determined by measuring the activity of its daughter²¹⁰Bi. The critical steps in the isolation of lead have been examined and discussed.     

Rapid determination of 210Po in water samples

A new rapid method for the determination of ²¹⁰Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of ²¹⁰Po in water samples have typically involved spontaneous auto-deposition of ²¹⁰Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 min to 24 h or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin?, often in combination with ²¹⁰Pb analysis. A new rapid method for ²¹⁰Po in water samples has been developed at the SRNL that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin^® (N,N,N′,N′ tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of ²¹⁰Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate ²¹⁰Po and actinide isotopes was also developed. This new approach, rapid separation with DGA resin plus microprecipitation for alpha source preparation, is a significant advance in radiochemistry for the rapid determination of ²¹⁰Po.     

Atmospheric deposition of 210Po and 210Pb in Malaysian waters during haze events

Biogenic burning as forest fire phenomena occurring from April to August each year in the Sumatra and Borneo islands are major sources of biogenic uranium–thorium decay series in marine systems. 30 samples were collected during the Ekspedisi Pelayaran Saintifik Perdana 2009 cruise (EPSP 2009 cruise) between 12th June and 1st August 2009 from the Straits of Malacca to the Sulu and Sulawesi Seas to study the effect of haze and the monsoon season on the deposition rate of ²¹⁰Po and ²¹⁰Pb in Malaysian waters. All samples were spiked with 1 ml of lead [Pb(NO₃)₂; 25 mg ml^?1] and 0.05 ml of Polonium-209 tracer (26.08 dpm ml^?1). ²¹⁰Po activity was determined by auto plating onto silver foil and counting using an alpha spectrometry system (Canberra model Alpha Analyst with a silicon-surface barrier detector). Lead that was collected via electrodeposition, formed lead sulphate (PbSO₄) precipitation. This precipitate was wrapped onto plastic discs and counted for ²¹⁰Pb beta activity using a gross alpha–beta counting system (Tennelec model LB-5100 low background gas-flowing anti-coincidence alpha/beta counter) after 1 month to allow bismuth ingrowths. The range of ²¹⁰Po activities varied between 51.08 ± 15.1 and 742.08 ± 220.34 Bq/kg, whereas the activity of ²¹⁰Pb ranged from 31.10 ± 4.20 to 880.23 ± 123.86 Bq/kg and ²¹⁰Po/²¹⁰Pb ratio value varied between sampling stations from 0.19 to 13.77. The contents of ²¹⁰Po were also statistically positively correlated with the amount of total suspended particulate especially those recorded during heavy haze period events.     

Determination of 210Pb, 210Bi and 210Po in natural drinking water

A new method for the radioanalytical determination of the ²²²Rn progenies ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Powill be presented, which has been improved for analyses of water samples fromdifferent regions in Austria. 1–2 liter samples were taken in polyethylenebottles prefilled with conc. HNO₃ to obtain 0.2M acidic solutions,thus avoiding adsorption effects. After adding 1.6 mg of inactive lead carrier,the water sample was evaporated to dryness, converted to the chloride formand dissolved in 1M HCl.     

Radiochemical analysis of210Po in coal gasification samples

The concentrations of²¹⁰Po in samples from a coal gasifier were determined by -pulse height analysis following separations from complex organic matrices. Samples were dissolved using wet acid digestion and persulfate fusion techniques and then extracted with trilaurylamine. Polonium was auto-deposited onto silver disks using²⁰⁹Po as a tracer for yield determination. The precision of the experimental method, determined on coal, was ±6% at the 95% confidence level. Excellent agreement was attained with published data on an EPA coal sample.This work was sponsored by the Office of Health and Environment, Office of Environmental Programs, and the Office of Coal Processing, U.S. Department of Energy, under contract DE-AC05-840R21400, with Martin Marietta Energy Systems, Inc.     

Determination of 210Po and uranium in high salinity water samples

A method for the determination of uranium and ²¹⁰Po in high salinity water samples has been elaborated. Both radionuclides are preconcentrated from 0.5 dm³ saline media by co-precipitation with hydrated manganese dioxide, followed by dissolution of the precipitate in 200 mL of 1 M HCl. Uranium isotopes ²³⁵U and ²³⁸U can be directly determined by ICP MS method with a detection limit of 0.01 ppb for ²³⁸U. Prior to a selective determination of ²¹⁰Po, the majority of other naturally occurring α-emitting radionuclides (uranium, thorium and protactinium) can be stripped from this solution by their extraction with a 50% solution of HDEHP in toluene. Finally, ²¹⁰Po is simply separated by direct transfer to an extractive scintillator containing 5% of trioctylphosphine oxide in Ultima Gold F cocktail and determined by an α/β separation liquid scintillation technique with detection limit below 0.1 mBq/dm³.     

Levels of 210Po and 210Pb in cigars

²¹⁰Po and ²¹⁰Pb concentrations have been determined in 58 cigar brands manufactured in 11 countries. Cuban and American cigars showed the lowest ²¹⁰Po content. The mean levels of ²¹⁰Po in Brazilian, European and Dominican cigars were almost identical and somewhat lower than the levels observed for cigars from other Latin American countries. Cuban, American and European cigars contained low levels of ²¹⁰Pb. Cigars from the remaining countries contained twice as much ²¹⁰Pb. The mean ²¹⁰Po/²¹⁰Pb ratio showed an excess of polonium. In the case of a one cigar-a-day smoker, the calculated annual absorbed dose due to ²¹⁰Po is -16 mGy.     

Assessment of 210Po deposition in moss species and soil around coal-fired power plant

In the present study, the depositions of ²¹⁰Po were assessed in the surface soil and some mosses species found in the area around coal fired power plant using radiochemical deposition and alpha spectrometry counting system. The purposes of the study were to determine activity concentrations of ²¹⁰Po in mosses and surface soil collected around coal-fired power plant in relation to trace the potential source of ²¹⁰Po and to identify most suitable moss species as a bio-indicator for ²¹⁰Po deposition. In this study, different species of mosses, Orthodontium imfractum, Campylopus serratus and Leucobryum aduncum were collected in May 2011 at the area around 15 km radius from Tanjung Bin coal-fired power plant located in Pontian, Johor. The ²¹⁰Po activity concentrations in mosses and soil varied in the range 102 ± 4 to 174 ± 8 Bq/kg dry wt. and 37 ± 2 to 184 ± 8 Bq/kg dry wt., respectively. Corresponding highest activity concentration of ²¹⁰Po observed in L. aduncum, therefore, this finding can be concluded this species was the most suitable as a bio-indicator for ²¹⁰Po deposition. On the other hand, it is clear the accumulation of ²¹⁰Po in mosses might be supplied from various sources of atmospheric deposition such as coal-fired power plant operation, industrial, plantation, agriculture and fertilizer activities, burned fuel fossil and forest; and other potential sources. Meanwhile, the main source of ²¹⁰Po in surface soil is supplied from the in situ deposition of radon decay and its daughters in the soil itself.     

210Pb and210Po analysis in sediments and soils by microwave acid digestion

A microwave acid digestion method prior to the determination of²¹⁰Pb and²¹⁰Po in sediments and soils is described. It involves an acid (HNO₃, HCl, HF and H₃BO₃ mixture) digestion with microwave heating in closed vessels at high pressures. Analyses carried out for various reference materials showed that the results were statistically equal to certified values and reproducibility was also assured. The advantage of the microwave technique compared to the traditional leaching procedures is that the solid materials are completely dissolved and, therefore, ca. 100% efficiency is achieved in the extraction of²¹⁰Po and²¹⁰Pb, even though a fraction is associated to the silica net. Moreover, time of analysis is drastically reduced, as are the risks associated to vapour inhalation and material corrosion.     

Determination of210Po in lead

A quantitative separation procedure for²¹⁰Po in lead has been developed by cupferron and dithizone extraction. The²¹⁰Po activity is plated on a silver foil for counting with a ZnS(Ag) scintillator, or by α-spectrometry with a surface barrier semiconductor. Different lead samples were analyzed ranging from very old lead with a negligible²¹⁰Po content to recently manufactured lead samples showing up to 9100 disintegrations per hour and per gram of lead. The reproducibility and the accuracy of the analyses are satisfactory.     

210Pb and210Po in tobacco-with a special focus on estimating the doses of210Po to man

Studies have been carried out on the solubility of Pu(III) oxalate by precipitation of Pu(III) oxalate from varying concentrations of HNO₃/HCl (0.5–2.0M) solutions and also by equilibrating freshly prepared Pu(III) oxalate with solutions containing varying concentrations of HNO₃/HCl, oxalic acid and ascorbic acid. Pu(III) solutions in HNO₃ and HCl media were prepared by reduction of Pu(IV) with ascorbic acid. 0.01–0.10M ascorbic acid concentration in the aqueous solution was maintained as holding reductant. The solubility of Pu(III) oxalate was found to be a minimum in 0.5M–1M HNO₃/HCl solutions containing 0.05M ascorbic acid and 0.2M excess oxalic acid in the supernatant.     

A rapid method for the separation of 210 Po from 210 Pb by TIOA extraction

A rapid method for the separation of ²¹⁰ Po from ²¹⁰ Pb was developed utilizing extraction of triisooctylamine (TIOA)/xylenein HCl+H₂O₂ medium. Polonium in the form of PoCl ₆ ²– was extracted into TIOA phase and ²¹⁰Pb remains in the aqueous phase. Lead-²¹⁰ was determined by -countingof its granddaughter, ²¹⁰ Po ingrown from ²¹⁰ Pb forsome period of time. Distribution of ²¹⁰ Po and ²¹⁰Pb in TIOA and aqueous phases was investigated in various concentrations ofHCl media. Hydrogen peroxide was used to further decompose organic matterand to remove sulfur to prevent its deposition on the silver disc. The improvedprocedure resulted in a good chemical yield (80–95%) and a good á-resolution.     

Sequential analysis methodology for 210Po and uranium analysis by extractive liquid scintillation spectrometry

Journal of Radioanalytical and Nuclear Chemistry - A methodology for separation and purification of 210Po from uranium, thorium and daughters has been studied. Solvent extraction coupled with...     

Measurements of210Pb and210Po in Japanese human hair

²¹⁰Pb and²¹⁰Po 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. The²¹⁰Po 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 the²¹⁰Pb concentrations from 0.7 to 6.5 mBq/g with a mean (median) value of 2.3±1.1 (2.0) mBq/g. The²¹⁰Po/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 of²¹⁰Po in human hair of Japanese may be due to the ingestion of animal protein mainly in the form of seafood.     

Analysis of210Po in marine samples

A method for determining²¹⁰Po in marine samples by wet dissolution, deposition onto silver disc and counting by -spectrometry is described. Recovery of polonium was obtained with²⁰⁸Po tracer.²¹⁰Po levels in fish from the Brazilian coast and sediments from Antarctic region were determined. Levels in fish ranged from 0.5 to 5.3 Bq·kg^–1 wet and for sediments, mean values of 10 mBq·kg^–1 were obtained.     

Estimation of sedimentation rates using 210Pb and 210Po at the coastal water of Sabah, Malaysia

Sediment cores were obtained from Teluk Brunei, Sipitang, Teluk Kimanis, Kota Kinabalu and Kuala Penyu at the coastal water of Sabah and analyzed for ²¹⁰Pb and ²¹⁰Po to estimate the sedimentation rates. The calculated sedimentation rates of ²¹⁰Pb and ²¹⁰Po varied from 0.003 to 0.049 cm/y and 0.74 to 8.77 cm/y, respectively. The highest sedimentation rates were determined for ²¹⁰Pb and ²¹⁰Po at stations located at Sipitang (mean: 0.027 cm/y) and Teluk Kimanis (mean: 5.53 cm/y), respectively. The sedimentation rate estimated for ²¹⁰Pb is not fully reliable because the activity of ²²⁶Ra was higher than that of ²¹⁰Pb and bioturbation was active at the sampling stations.     

Determination of210Pb and210Po in human tissues of Japanese

To determine the levels of²¹⁰Pb and²¹⁰Po 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 the²¹⁰Pb and²¹⁰Po present. Among the tissues analyzed, the highest concentrations of²¹⁰Pb and²¹⁰Po were observed in bone (sternum), liver, and kidneys. The total body burden of²¹⁰Pb and²¹⁰Po was found to be approximately 427 pCi and 514 pCi, respectively. This estimated²¹⁰Po value did not differ significantly from values found in populations in the U.S.A. and European countries.     

Quality control strategy for the determination of 210Po

A quality control programme is presented for the determination of ²¹⁰Po in samples from the phosphate ore-processing industry. Accuracy and precision of selected steps of the analytical procedure are quantified and the change in these parameters is monitored by analysis of hundreds of reference samples during the last two years.     

Analysis of 210Pb and 210Po in Brazilian foods and diets

Radiochemical procedures for the analysis of ²¹⁰ Pb and ²¹⁰ Po in foods and diets are presented. Because of the low beta energy of ²¹⁰ Pb, its analysis was based on a separation of the daughter radionuclide ²¹⁰ Bi by precipitation of lead sulphate, ²¹⁰ Bi ingrowing and beta counting of this nuclide. ²¹⁰ Po analysis was based on wet dissolution of the sample, deposition onto silver disc and counting by alpha-spectrometry. Levels of these radionuclides in individual items and diets of selected university students were determined in order to evaluate the intakes of ²¹⁰ Pb and ²¹⁰ Po as well as the dose due to ingestion of foods and diets in São Paulo city.     

Investigative study on 210Po activity concentration in naturally grown medicinal herbs

Journal of Radioanalytical and Nuclear Chemistry - Among various naturally grown-medicinal herbs investigated, the estimated natural radioactivity content of 210Po is found to be the highest in the...