Transfer of210Pb and210Po to the environment during mining and processing of uranium ores

Transfer of²¹⁰Pb and²¹⁰Po 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 for²¹⁰Po and²¹⁰Pb determination.     

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.     

Anthropogenic emissions of210Po,210Pb and226Ra in an estuarine environment

An extensive study on the distribution of natural radionuclides in an estuarine ecosystem located in Southwestern Spain is presented. This environment is highly affected by the wastes released by a phosphoric acid industry which uses phosphate rocks as raw material for fertilizer production. This rock has generally high concentrations of U and its daughters. The estuary is formed by two rivers, Odiel and Tinto, which have a common mouth into the Atlanic Ocean and a salt marsh (Odiel marsh) affected by the income of Odiel riverwaters. This river receives directly the liquid and part of the solid (gypsum) wastes released from the industries. Besides that, most of the phosphogypsum wastes are stored in uncovered piles at the right margin of the Tinto river. The study has concluded that the wastes from such industries are the cause of the enhanced concentrations found at the bed of both river channels as well as the enhancement found in surface soils in certain zones of the Odiel wet marshland. Indeed, the Northern marsh and the Mojarrera channel at the Odiel marsh seem to be the main sinks of the contaminant released by the phosphoric acid industry.     

210Pb(210Po) speciation of aquatic deposits: Refinement and utility

A refined chemical procedure for speciation studies of sediments has been thoroughly examined. The suggested method, although only tested on²¹⁰Pb (²¹⁰Po), could be applied to other chemical species, especially heavy metals and radioactive nuclides. Successive dissolutions using dilute HC1 (1–2.5%) and NaOH (0.5–1%) proved that the geochemistry of fulvic, humic, and mineral compounds plays an important role in the mobility, transport, and accumulation of²¹⁰Pb in various aquatic systems. This work demonstrates that²¹⁰Pb, as well as analogous isotopes and metals-based dating and tracing applications, could be further improved and extended using proper speciation techniques. The procedure given here allows not only evaluation of supported and unsupported²¹⁰Pb but also the resolution of anomalies in modelling biogeochemical cycles.Supported by the Swedish Natural Science Council and the Spanish CICYT contract PB86-0207.     

Trace elements, 210Po and 210Pb in a selection of berries on commercial sale in Italy

The occurrence of ²¹⁰Pb, ²¹⁰Po, trace elements was assessed in a selection of berries on commercial sale in Italy. Data confirmed that berries might serve as an important source of essential elements. The ²¹⁰Pb, ²¹⁰Po concentrations found were higher than the reference values reported by UNSCEAR for roots and fruits in the world. There is no risk whatsoever from the intake of toxic elements as Al, As, Cd, Pb, Ni, Hg in berriberries analyzed; it is necessary, however, continuously monitored the levels of these elements to protect consumers against potential adverse health effects especially when consumed in large quantities.

     

Determination of (210)Pb, (210)Bi and (210)Po in natural waters and other materials by electrochemical separation

An improved method for determination of (210)Pb, (210)Bi and (210)Po in both natural waters and solid materials has been developed. Polonium-210 is spontaneously plated onto a silver disc from dilute hydrochloric acid medium. Bismuth-210 is then electro-deposited onto a platinum gauze cathode directly from the same solution, with a graphite rod as anode. Finally, (210)Pb is electro-deposited from a fluoroborate medium onto the same platinum gauze, used as the anode. All three nuclides are subsequently measured by standard low-level alpha and beta counting techniques. The speed of this method (approximately 6 hr per sample after pretreatment) is a distinct advantage over existing techniques, as (210)Bi must be quickly separated from (210)Pb because of its 5.02-day half-life. Another advantage of this method is that the chemical form of the sample solution is suitable for use of established separation schemes for determining other decay-series isotopes (U, Th, Pa, etc.) after the three short-lived nuclides have been processed.     

An efficient quantitative technique for the simultaneous analyses of radon daughters (210)Pb, (210)Bi and (210)Po

An improved and time efficient technique has been developed for quantitative determination of the long-lived (222)Rn daughters ((210)Pb, (210)Po and (210)Bi) in atmospheric and oceanic samples. The sample is first spiked with yield tracers for polonium (208 or 209), bismuth (207), and lead (stable lead carrier). These nuclides may then be scavenged through iron hydroxide precipitation and redissolved in a dilute (pH approximately 2) nitric acid plating medium with citrate and hydroxylamine hydrochloride at 90 degrees centrigrade with constant stirring. First a silver planchet is suspended in the solution which plates polonium to high efficiency. Second, a nickel planchet is suspended in the same solution which is maintained hermetic (e.g. bubbling with helium) and bismuth is plated next with high efficiency. Third, lead is purified from the same solution using anion exchange techniques and isolated for beta counting as the sulfate. Polonium is analyzed by isotope dilution alpha spectrometry. Bismuth and lead are analyzed by anti-coincident beta counting in a low level shield. In the case of bismuth, the 207 tracer is added in quantities at least comparable to the background of the beta system such that counting before and after the decay of (210)Bi gives the bismuth yield. The unique characteristics of this technique are its speed and efficiency; all three radon daughters can be isolated for counting within 4 hr of pre-treating the sample. The remaining solution can be treated subsequently for other analyses as appropriate.     

210Pb and 210Po radionuclides in the urban air of Lodz, Poland

The concentration of two important radionuclides: ²¹⁰Pb and its decay product ²¹⁰Po in the urban air in the center of the Polish city of Lodz were measured during the winter and spring seasons of 2008–2009. Urban airborne particulate matter was collected using two methods: an Anderson 9-stage impactor, and a high-volume aerosol sampler type ASS500 working in the frames of the aerosol sampling network in Poland, established for radionuclide monitoring. Average concentrations for 10 months sampling period for ²¹⁰Pb and ²¹⁰Po were 0.556 and 0.067 mBq/m³, respectively. However remarkable fluctuations due to meteorological condition were observed: from 0.010 to 0.431 mBq/m³ for ²¹⁰Po and from 0.167 to 1.847 mBq/m³ for ²¹⁰Pb. The highest concentrations, almost 60% of the total activities, of both radionuclides were found in the first two fine aerosol fractions with particle diameters below 0.36 μm. The aerosol residence times calculated from the ²¹⁰Po/²¹⁰Pb ratio ranged from 7 to 120 days.     

Time-series observations of 210Po and 210Pb radioactivity in the western North Pacific

We carried out time-series observations of ²¹⁰Po and ²¹⁰Pb radioactivity in the western North Pacific Ocean. The sinking fluxes of particulate organic carbon (POC) in the mesopelagic zone were estimated from ²¹⁰Po radioactivity during several seasons in the subarctic and subtropical regions of the western North Pacific. The seasonal changes of POC fluxes at a depth of 400 m were larger in the subarctic region than in the subtropical region. The annual mean POC flux at a depth of 400 m was larger in the subarctic region (57 mgC m^?2 day^?1) than in the subtropical region (36 mgC m^?2 day^?1). The annual mean of the e-ratio (the ratio of POC flux to primary productivity) in the subarctic region (18 %) was about twice the e-ratio in the subtropical region (10 %). These results imply that the efficiency of the biological pump is larger in the subarctic region than in the subtropical region of the western North Pacific.     

Determination of environmental actinide nuclides and210Pb(210Po) by low-energy photon spectrometry with alpha-spectrometry

Low-energy photon spectrometry with -spectrometry was used to determine the environmental concentrations of low-level actinides and other nuclides, especially²¹⁰Pb and²¹⁰Po. The isotopic ratio of²⁴⁰Pu/²³⁹Pu was successfully determined by measuring L_x-ray/-ray counting ratio. A reliable method has been developed for the determination of extremely low-level²³⁷Np global fallout in environmental samples. The non-destructive determination by Ge-LEPS for natural²¹⁰Pb in various samples (tobacco leaves, commercially available tobacco, etc.) was also carried out with the determination of²¹⁰Po by -spectrometry using²⁰⁹Po as a yield tracer.     

The assessment of radiological risks associated with the ingestion of 210Po, 210Pb,and 137Cs in marine organisms collected from the local fish market of Kenitra,Morocco

Journal of Radioanalytical and Nuclear Chemistry - 210Po, 210Pb, and 137Cs activities were measured using gamma and alpha spectrometry in commonly consumed seafood collected from the local fish...     

The radiation dose and distribution coefficient of 210Po and 210Pb concentrations in aquatic environs of major rivers of coastal Karnataka

The activity of ²¹⁰Po and ²¹⁰Pb was measured in different matrices of aquatic ecosystem of the major rivers of Coastal Karnataka viz, Kali, Sharavathi and Netravathi. The environmental samples such as surface water, suspended particulate matter and sediment have been subjected to analyses. The activity of these two radionuclides were determined by radiochemical separation of ²¹⁰Po and counting the activity using a ZnS(Ag) alpha counter. The activity ratio of ²¹⁰Po and ²¹⁰Pb and correlation between the activity of these radionuclides were studied. From the measured concentration of ²¹⁰Po and ²¹⁰Pb, the internal Committed Effective Dose to the population for the study area was calculated. The distribution coefficient K_d between water, suspended particulate matter and sediments have been calculated to understand the distribution and accumulation of these radionuclides in different matrices of the aquatic environment.

     

7Be and 210Pb concentrations in air in Málaga (Spain)

Measurements of ⁷Be and ²¹⁰Pb in atmospheric air (1 m above the ground) have been carried out each week over one and a half year period. The method used to determine ⁷Be and ²¹⁰Pb activities is based on the total amount of radioactive aerosols filtered from the air. The activities of ⁷Be and ²¹⁰Pb were determined by a hyper-pure germanium detector using standard gamma-spectrometry. The average weekly concentrations of ⁷Be were in the range of 1.21-12.1 mBq^.m^-3 and for ²¹⁰Pb in the range of 0.8-2.4 mBq^.m^-3. The weekly variations were discussed in relation to various meteorological factors. It can be said that our results showed a prevailing influence of weekly average temperature for ⁷Be concentration and the weight of aerosols and wind speed for ²¹⁰Pb oncentrations.     

Local variations of atmospheric 222Rn and 210Pb concentrations in Badgastein (Austria)

²²²Rn was measured and aerosols for ²¹⁰Pb determination were collected simultaneously outdoors at ground level near the train station of Badgastein (1080 m a.s.l.), and later on also on the nearby Stubnerkogel (2230 m a.s.l.). Radon concentrations at lower altitude were up to 140 Bq/m³, on the mountain the usual background levels were found. In contrary to the differing radon levels, the ²¹⁰Pb activity concentrations were in the same order of magnitude for both locations with values between 0.16 and 0.77 mBq/m³.     

Evaluation of measurement uncertainty in the determination of 210Pb and 210Po using beta counting and alpha spectrometry

 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 PbSO₄ 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     

The role of Cherenkov and liquid scintilation counting in evaluating the anion-exchange separation of210Pb−210Bi−210Po

Using as eluent a sequence of 3M HCl, 12M HCl, and 8M HNO₃, a mixture of²¹⁰Pb,²¹⁰Bi, and²¹⁰Po may be clearly separated on a column of Dowex 1×2−100 anion exchange resin. A Cherenkov count in H₂O and the variation in count rate with time confirm that the nuclides emerge in the order²¹⁰Pb→²¹⁰Bi→²¹⁰Po. If 12M HCl is replaced by 1.5M H₂SO₄/2.3 M Na₂SO₄, a clean separation also results, but recovery of²¹⁰Po becomes considerably more difficult. All three nuclides are readily detectable by liquid scintillation counting, with the efficiency for²¹⁰Pb in the 60–70% range. The Cherenkov aqueous counting efficiency for²¹⁰Bi is ∼14–15%.     

A practical and accurate method for the determination of 234Th simultaneously with 210Po and 210Pb in seawater

A practical technique has been developed for the determinations of (234)Th simultaneously with (210)Po and (210)Pb in seawater samples, which greatly simplifies the on-board chemical procedures and enables an accurate correction of (234)Th ingrowth. A unique feature of this technique lies in the exact determination of co-precipitated (238)U following Fe(OH)(3) precipitation which leads to an exact correction of ingrown (234)Th between Fe(OH)(3) precipitation and U/Th separation. Such a correction eliminates several cumbersome on-board chemistry steps (such as Po plating, Fe(2+) oxidation, and 9 N HCl anion exchange) required in regular procedures to eliminate the (234)Th ingrowth. The total time required for on-board sample treatment (spike equilibration, Fe (OH)(3) co-precipitation and filtration) could be less than 10 h which significantly increases the sample processing efficiency and data throughput.     

A modified method for the sequential determination of 210Po and 210Pb in Ca-rich material using liquid scintillation counting

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.

     

Activity concentrations of 210Po in the soft parts of cockle (Anadara granosa)at Kuala Selangor, Malaysia

Polonium-210 has been measured in the soft parts of Anadara granosa purchased at Kuala Selangor, West Coast of Malaysia in August 2001, April 2002 and September 2002. It is shown that ²¹⁰Po is non-uniformly distributed within cockles of various sizes (i.e., 2.5, 3.0, 3.5 and 4.0 cm of shell length) and the concentration of ²¹⁰Po in the soft parts of cockle was significantly different (p<0.05) due to sampling date. The highest value was observed in the smallest cockle with a shell length of 2.5 cm (411.6±26.16 Bq/g dry wt.). It is clear that there is an allometric relationship between ²¹⁰Po activity concentration and individual cockle weight. This may reflect on the differences of metabolic rate and growth age of cockles. The mean activity concentration of ²¹⁰Po measured in Kuala Selangor filtered water were 1.75±0.17, 0.79±0.08 and 1.13±0.20 Bq/kg for August 2001, April 2002 and September 2002, respectively. The yield concentration factors for ²¹⁰Po in the soft parts of cockles varies from 27.3^. 10³ to 106.9^. 10³. This revised version was published online in July 2006 with corrections to the Cover Date.     

A study on 210Pb and 210Po levels in different tobacco types produced in Turkey and the estimation of the committed effective dose

Journal of Radioanalytical and Nuclear Chemistry - In this study, 210Pb and 210Po activity concentrations in tobacco samples produced in 12 different regions of Turkey have been investigated and...