Estimation of 241Am and 239Pu activity embedded in the tissue using portable planar HPGe detector.

This paper describes a procedure for the estimation of 241Am and 239Pu activity present in the human tissue by measuring the depth of contaminant using a portable Planar High Purity Germanium detector (HPGe). The ratios of photopeak counts of X-rays or gammas obtained with the detector coupled to collimator are calculated for the estimation of depth of the contaminant and the optimum one is determined. Since Minimum Detectable Activities (MDA) for the detector coupled to a collimator are higher than that of bare detector, activity must be estimated using bare detector, after locating the contaminant. Two methods are described for the estimation of plutonium coexisting with 241Am: (i) Abundance and isotopic correction for 239Pu (ii) and 239Pu:241Am ratio. The procedure to estimate 239Pu when plutonium isotopes alone are present is also established. An optimum monitoring period to detect the minimum value of intake for both radionuclides corresponding to chelation therapy and excision is also derived.

Set up and test of an anticoincidence system for the detection of radioactive xenon by gamma spectrometry system.

The aim of this work is based on the optimisation of a gamma spectrometry system in anticoincidence for the detection of noble gases, in particular the radioactive isotopes of xenon. These four radionuclides are of particular interest for the Comprehensive Nuclear Test-Ban Treaty (CTBT). The Laboratory of the ENEA Research Centre of Brasimone, where the experimental apparatus has been set up to carry out the measurements of 131mXe, 133Xe, 133mXe and 135Xe, is able to provide, if necessary, data and analysis on noble gases. The apparatus provides for the sampling of outdoor air, the passage through filters and in activated carbons maintained at cryogenic temperatures to allow xenon absorption. Finally, gas extraction and xenon volumes are analyzed by means of gas chromatography and a thermal conductivity detector. At the end of the extraction an aluminium cylinder containing radioxenon is analyzed by high resolution gamma spectroscopy using a High Purity Germanium Detector P-type. The signals produced by the interaction of cosmic rays with the crystal have been recognized as the main cause of the increase of the detector background because they give rise to the Compton continuum and, as a result, they affect the value of the minimum detectable activity (MDA). In order to overcome this effect, a system in anticoincidence has been developed using two plastic scintillators, placed over the shielding of the HPGe detector, which send pulses recording within a time delay window located in the germanium multichannel analyzer: at the time the signal arrives from the scintillator, the gate blocks data acquisition to avoid recording pulses generated by cosmic radiation. For both configurations of the system (with and without the anticoincidence apparatus operating) the energy, and efficiency calibrations have been carried out using a certified multigamma-ray calibration source to assess the performance.

A rapid method for determining low concentrations of 210Pb in drinking water using MnO2 fibers.

A rapid method for determining low activity concentrations of 210Pb in drinking water was developed and tested. The method consists of a few stages for sample preparation that involve passing 12 L of water through a column with acrylic fibers implanted with MnO2 (used to adsorb 210Pb). The MnO2 fibers are oven-dried, compressed and measured by a broad-energy germanium detector used to quantify 210Pb via its characteristic 46.5 keV γ-ray. The time taken for sample preparation is approximately 4 h and recovery factors for lead in tap water of 87 ± 3% were achieved. After a measurement duration of 4 h, the minimum detectable activity concentration reaches 0.02 Bq/L for 210Pb, being well below the respective limit for drinking water in Israel (0.2 Bq/L) as well as the value recommended by the World Health Organization (0.1 Bq/L). Furthermore, a measurement duration of 48 h provides a minimum detectable activity concentration of ∼0.006 Bq/L, which is similar in magnitude to other, well-established methods that rely on lengthy and rather complex procedures. Thus, the combination of MnO2 fibers and gamma-ray spectrometry may be attractive for routine use by analytical laboratories that monitor radioactivity in drinking water.

RADIOACTIVITY ASSESSMENT OF SURFACE SOIL IN THE VICINITY OF A URANIUM MINE IN MALAWI.

The activity concentrations of 238U, 232Th and 40K in the soil of areas surrounding the Kayelekera uranium mine were assessed. This study aims to provide a comprehensive profile of soil radioactivity distribution in the area surrounding the uranium mine to determine radiological hazards associated with mining and processing activities. Soil samples were analysed using gamma-ray spectrometry with a high-purity germanium detector. Mean specific activities of 238U, 232Th and 40K were 58.3 ± 3.7, 40.3 ± 0.3 and 590.9 ± 63.9 Bq kg-1, respectively. Results from this study have indicated changes in radioactivity levels of naturally occurring radioactive materials in the area surrounding the understudied mine, with certain areas close to the mine site showing elevated levels of 238U, highlighting the need for systematic and periodic monitoring.

Photochemical vapor generation for germanium: synergistic effect from cobalt/chloride ions and air-liquid interfaces.

Photochemical vapor generation (PVG) of germanium (Ge) was first reported in this work. The synergistic effect from cobalt/chloride ions and air-liquid interfaces was found for the PVG of Ge. No obvious signal response was observed from the standard solution of Ge in 10% (v/v) formic acids (FAs) under UV irradiation. The addition of 300 mg L-1 of Co2+ and 30 mmol L-1 of Cl- resulted in enhanced photochemical reduction for Ge, and the introduction of air-liquid interfaces proceeding and succeeding the sample solution caused another 4.6 folds of enhancement in signal response of Ge. Under the selected condition, the limit of detection (LOD, 3σ, n = 11) was obtained to be 0.008 ng mL-1 with inductively coupled plasma mass spectrometry (ICP MS) measurement. A good precision, expressed as a relative standard deviation (RSD, n = 7) of 2.0%, was found from replicated measurements of 2 ng mL-1 of Ge. The generation efficiency was found to be no better than 9 ± 2%. The PVG mechanism of Ge was investigated in this work. The new finding is useful for understanding the principle of PVG, and further exploring the analytical and environmental application of PVG.

Toward 'element balance' in ADHD: an exploratory case control study employing hair analysis.

Background: Head hair analysis has been used for decades to clarify mineral relationships to symptoms of ADHD, but there is little consensus among findings. We sought to explore 33 hair element concentrations and their 528 calculated ratios among two groups of boys, one with ADHD and one without.Method: 107 boys aged 7-12 years were recruited; 55 with ADHD and 52 non-ADHD Controls. Hair minerals were compared using Mann-Whitney U tests, p<0.01 was used for significance. Dietary data were obtained using a 138 item food frequency questionnaire (FFQ).Results: There were three group differences on individual elements: bismuth/Bi: 8 fold higher in ADHD, chromium/Cr: 15% lower in ADHD and germanium/Ge: 11% lower in ADHD, Cr level being the strongest predictor of ADHD symptoms. We found thirty significant group differences in element ratios, two thirds involving Bi and eight of these showing that as ADHD severity increased, the ratios with Bi as the denominator decreased (r ranging from -0.263 to -0.433, p<0.01). From the FFQ, tinned fruit was consumed more often in the ADHD group. Hair arsenic levels were somewhat elevated across both ADHD and Control groups.Discussion: While element 'imbalance' appears to be associated with ADHD, we did not replicate any previous study results of group differences on individual elements. We have raised the possibility that the ratios may be far more important than any one individual element in better elucidating the effects that minerals may have on the pathogenesis of ADHD. These are cautionary findings requiring replication.

Calibration and use of well-type germanium detectors for low-level gamma-ray spectrometry of sediments using a semi-empirical method.

Gamma-ray spectrometry is a widely used technique to quantify the presence of numerous radionuclides in environmental samples. In this work, we describe a methodology for efficiency calibration of four well-type germanium detectors and their use for the determination of low-level activities of gamma emitters in sediment samples. An experimental efficiency calibration for each detector was built with three materials for 17 energies, ranging from 46.5 keV to 1460 keV. For efficiency transfer to different geometries and sample types, we used the effective solid angle approach (ET-Ω method). Final calibrations were calculated for all detectors, several counting geometries, and elemental composition of selected sample types. Calibrations were validated with six reference materials. This methodology allowed to reliably analyze nine gamma emitters (210Pb, 241Am, 234Th, 228Ac, 214Pb, 208Tl, 137Cs, 134Cs and 40K) in sediment samples. Using these calibrations, gamma emitter profiles of sediment cores from contrasting aquatic systems (lake, intertidal, marine and deep-sea areas) provided reliable profiles of 210Pb and artificial radionuclides useful for dating and stratigraphic interpretation. A protocol to implement this methodology is also presented.

PERFORMANCE EVALUATION OF THE EQUIPMENT FOR MEASURING RADIOACTIVITY IN WHOLE FOODSTUFFS WITHOUT DESTRUCTIVE SAMPLE PREPARATION DEVELOPED AFTER THE FUKUSHIMA NPP ACCIDENT.

Recently, several types of instruments for measuring radioactivity in whole foodstuff were developed by manufacturers, in which any sample preparation technique such as machining was avoided, and such types of instruments are employed by agricultural producers or municipality radioactivity testing stations in Fukushima. In this study, radioactivity in various kinds of 91 samples collected by residents were measured by use of instruments for radioactivity measurement in whole samples, and the activity in each sample was also measured by use of the conventional gamma-ray spectrometry technique using calibrated Ge detectors after the sample machining procedure. The results obtained by instruments for measurement in whole samples were roughly proportional to the result obtained by a conventional technique, although large differences or unexpected variations were found in some specimens.

Germanium speciation using liquid chromatography-inductively coupled plasma-triple quadrupole mass spectrometry: Germanium in biological and chemical leaching solutions of fine-grained residues from copper smelting.

A new method for the speciation analysis of inorganic germanium (Ge(OH)4), monomethylgermanium (MMGe) and dimethylgermanium (DMGe) in complex acidic aqueous leachates by liquid chromatography coupled to inductively coupled plasma mass spectrometry (LC-ICP-MS) was developed. The species are separated using anion exchange chromatography with tartrate added as complexing agent. When tartrate was added to the sample and the eluent chromatography was not affected by sulfate concentrations up to 100 mM. The He collision mode (MS/MS mode) removes polyatomic plasma- and matrix-based interferences, thus providing the selectivity in Ge speciation required for the complex samples. With LOQs of 62 ng L-1 (DMGe), 67 ng L-1 (MMGe) and 164 ng L-1 (Ge(OH)4) the method was sufficiently sensitive for the intended application. The developed method was applied to biological and chemical leachates of sulfidic flue dust from copper shale smelting (Theisen sludge). Only small amounts of methylated Ge species were determined next to inorganic Ge in these leachates.

Germanium in the soil-plant system-a review.

Germanium (Ge) is widespread in the Earth's crust. As a cognate element to silicon (Si), Ge shows very similar chemical characteristics. Recent use of Ge/Si to trace Si cycles and changes in weathering over time, growing demand for Ge as raw material, and consequently an increasing interest in Ge phytomining have contributed to a growing interest in this previously rather scarcely considered element in geochemical studies. This review deals with the distribution of Ge in primary minerals and surface soils as well as the factors influencing the mobility of Ge in soils including the sequestration of Ge in secondary mineral phases and soil organic matter. Furthermore, the uptake and accumulation of Ge in plants and effects of plant-soil relationships on the availability of Ge in soils and the biogeochemical cycling of Ge are discussed. The formation of secondary soil minerals and soil organic matter are of particular importance for the concentration of Ge in plant-available forms. The transfer from soil to plant is usually low and shows clear differences between species belonging to the functional groups of grasses and forbs. Possible uptake mechanisms in the rhizosphere are discussed. However, the processes that are involved in the formation of plant-available Ge pools in soils and consequently its biogeochemical cycling are not yet well understood. There is, therefore, a need for future studies on the uptake mechanisms and stoichiometry of Ge uptake under field conditions and plant-soil-microbe interactions in the rhizosphere as well as the chemical speciation in different plant parts.

Assessment of gamma radiation and associated radiation hazards in coastal sediments of south east coast of Tamilnadu, India with statistical approach.

Gamma spectroscopy was performed to determine the concentrations of 226Ra, 232Th and 40K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg-1 for 226Ra, 85.67 Bq kg-1 for 232Th and 425.72 Bq kg-1 for 40K. The average activity concentration of 232Th and 40K are slightly higher and 226Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Raeq) Absorbed Gamma Dose Rate (DR), Annual Effective Dose Rate (HR), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE), Internal Hazard Index (Hin) and External Hazard index (Hex) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides.

Association of Periodontitis with the Concentration Levels of Germanium and Tin in Hair.

The purpose of this study was to investigate whether or not the concentration levels of certain kinds of trace elements in hair are associated with periodontitis. We studied a total of 109 participants, which are composed of 25 participants with periodontitis and 84 participants without periodontitis. Periodontal conditions were assessed by measuring the periodontal clinical attachment loss and pocket depth, which were determined at six sites of all teeth. Periodontitis was defined according to the criteria of periodontitis proposed by CDC-AAP. The hair samples were washed with acetone, water, and extran (1%v/v), and then aliquots of hair samples were wet-ashed. This sample solution was analyzed by Perkin-Elmer Mass Spectrometer. The odds ratios and 95% confidence intervals of the concentration levels of trace elements for periodontitis were calculated by multivariate logistic regression analysis. After adjusting all confounders, it was found that the higher concentration level of germanium in hair was significantly and positively associated with periodontitis (odds ratio [OR] 7.12; 95% confidential interval [CI] 2.03-25.00). The higher concentration level of tin in hair was significantly and negatively associated with periodontitis (OR 0.27; 95% CI 0.08-0.94). It was concluded that there was a significant relationship between periodontitis and the concentration level of germanium and tin in hair.

Application of ISOCS system in the laboratory efficiency calibration.

ISOCS (In Situ Counting Object System) from Canberra is applied in laboratory for creating efficiency calibrations of good quality without using radioactive standards. Besides of typical sample containers used in laboratory, ISOSC system also allows modelling containers and objects of almost any shape and elemental composition. The study was based on gamma spectrometry with HPGe semiconductor detector with electronics and software spectrum analysis GENIE 2000 + ISOCS. Measuring set is equipped with portable shield system with set of collimators ISOCS Shield Systems Model ISOXSHLD from Canberra. This shielding system provides attenuation of gamma background radiation with average value 33 (for gamma energies from 186 keV to 2615.5 keV). The portable shield system can be used for low-background laboratory measurements. For this purpose a measuring vessel of new geometry was constructed: the polystyrene cylinder with a height of 40 mm and a diameter of 70 mm. The efficiency calibration for this container was performed using both ISOCS system and classical calibration standard in the same geometry. In order to verify the correctness of performed calibration procedures, the measurements of radioactive standard CBSS 2 were made. The results of both calibrations were compared with the data from the standard certificate. Satisfactory agreement was achieved. Mean percentage difference between results from ISOCS calibration compared to reference values is 6% for all isotopes activities in CBSS 2 standard. The set of collimators was used to develop efficiency calibration for in situ measurements of the soil surface. Test measurements were carried out at the area of the Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland (IFJ PAN). Two measurement methods were compared: in situ and laboratory gamma spectroscopy. The obtained average results (from all 10 measuring points) are consistent within the range of measurement uncertainty.

A rotating-slit-collimator-based gamma radiation mapper.

For situations with radioactive material out of control where it may be physically difficult or prohibited to access areas close to the source, measurements from distance may be the only way to assess the radiation environment. Using collimated detectors will provide means to locate the direction of the radiation from the source. To investigate the possibilities of mapping gamma emitting radioactive material in a closed non-enterable area, a tentative system for mapping radioactive materials from a distance was built. The system used a computer controlled cylindrical rotating slit collimator with a high purity germanium detector placed in the cylinder. The system could be placed on a car-towed trailer, with the centre of the detector about 1.4 m above ground. Mapping was accomplished by the use of a specially developed image reconstruction algorithm that requires measurements from two or more locations around the area to be investigated. The imaging capability of the system was tested by mapping an area, 25 by 25 m2, containing three 330 MBq 137Cs point sources. Using four locations outside the area with about 20 min measuring time in each location and applying the image reconstruction algorithm on the deconvoluted data, the system indicated the three source locations with an uncertainty of 1-3 m. The results demonstrated the potential of using collimated mobile gamma radiometry combined with image reconstruction to localize gamma sources inside non-accessible areas.

Multielemental Determination of As, Bi, Ge, Sb, and Sn in Agricultural Samples Using Hydride Generation Coupled to Microwave-Induced Plasma Optical Emission Spectrometry.

A microwave-induced plasma optical emission spectrometer with N2-based plasma was combined with a multimode sample introduction system (MSIS) for hydride generation (HG) and multielemental determination of As, Bi, Ge, Sb, and Sn in samples of forage, bovine liver, powdered milk, agricultural gypsum, rice, and mineral fertilizer, using a single condition of prereduction and reduction. The accuracy of the developed analytical method was evaluated using certified reference materials of water and mineral fertilizer, and recoveries ranged from 95 to 106%. Addition and recovery experiments were carried out, and the recoveries varied from 85 to 117% for all samples evaluated. The limits of detection for As, Bi, Ge, Sb, and Sn were 0.46, 0.09, 0.19, 0.46, and 5.2 µg/L, respectively, for liquid samples, and 0.18, 0.04, 0.08, 0.19, and 2.1 mg/kg, respectively, for solid samples. The method proposed offers a simple, fast, multielemental, and robust alternative for successful determination of all five analytes in agricultural samples with low operational cost without compromising analytical performance.

Modified matrix volatilization setup for characterization of high purity germanium.

Modified matrix volatilization (MV) method has been described to characterize high purity germanium material of 7 N (99.99999%) purity. Transport of both, the chlorine gas generated in-situ in this method and the argon gas (carrier) is fine controlled by means of a mass flow controller. This enabled both uniform reaction of chlorine gas with the germanium matrix and smooth removal of germanium matrix as its chloride. This resulted in improvement in the reproducibility of the analytical results. The use of quartz reaction vessel has lead to the reduction in the process blank levels. The combined effect of these modifications in the MV setup has resulted in very consistent and low process blanks and hence improved detection limits of this method. Applicability of the method has been expanded to rare earth elements and other elements after examining their recoveries. The quantification is done by using inductively coupled plasma quadrupole mass spectrometer (ICP-QMS) and continuum source graphite furnace atomic absorption spectrometry (CS-GFAAS). In the absence of certified reference materials for high pure germanium, the accuracy of the method is established by spike recovery tests. The precision of the method has been found to vary from 1 to 30% for concentrations between 1 and 30 ng g(-1). The limits of detection (LOD) for the target analytes are found to be between 18 and 0.033 ng g(-1).

Impact of Recent Change in the National Institute of Standards and Technology Standard for 18F on the Relative Response of 68Ge-Based Mock Syringe Dose Calibrator Standards.

UNLABELLED: As a result of a recent change in the National Institute of Standards and Technology (NIST) activity standard for (18)F, we have determined new relative response ratios for a (68)Ge solid epoxy mock syringe source used in activity calibrators as a long-lived substitute for (18)F. New standardized solutions of each radionuclide were used to determine the response ratios while maintaining traceability to national standards. This work updates our previously published data from 2010. METHODS: Following our previously published methodology, solution-filled mock syringe sources, identical in geometry to the solid (68)Ge epoxy calibration source currently on the market, were prepared using NIST-calibrated solutions of (68)GeCl4 and (18)F-FDG and directly compared in several models of activity calibrators to determine empirically the relative response ratios for these 2 radionuclides. RESULTS: The new relative response ratios measured in this study reflect the change in (18)F activity measurements that arise from the recent -4% change in the NIST activity standard. The results allow the (68)Ge activity of the mock syringe source to be expressed in terms of equivalent (18)F activity, with a relative combined standard uncertainty of about 0.8% for the activity calibrators used in this study. CONCLUSION: This work revises our previously derived relative response ratios for (18)F and (68)Ge by -3.7%, allowing users of the commercial mock syringe surrogate source to calibrate their activity calibrators in a way that is consistent with the recent change in the NIST (18)F standard.

[Determination of Trace Germanium in Plant Samples by Dry Ashing-Atomic Fluorescence Spectrometry].

To reduce the limit of detection (LOD) and allow the accurate determination of Ge, a dry ashing method was performed to enrich the Ge in plant samples. A method for the determination.of trace Ge in plant samples by HG-AFS was established. Study of the effect of temperature on the ashing of plant samples showed that no volatile loss of Ge occurred even at 900 °C. Additional experiments indicated that a 4 h burning process at 600 °C would be sufficient to fully ash the plant samples. Various digestion methods (involving nitric acid, hydrofluoric acid, and sulfuric acid digestion methods) for ashed samples were investigated. High-temperature ashing with large sample weights was used, which could reduce the reagent doses and the method's LOD effectively and simultaneously, the precision of the method was improved. The method's LOD was 0.27 ng · g(-1), and the relative standard deviation was 3.99%-6.81%. Verified with national biological reference materials (grade I), the proposed method was accurate and reliable.

[Interlaboratory study on migration test of antimony and germanium for food-contact polyethylene terephthalate].

An interlaboratory study was performed to evaluate a migration test method of antimony (Sb) and germanium (Ge), based on the Japanese Food Sanitation Law for food- contact polyethylene terephthalate. Eighteen laboratories participated, and quantified Sb and Ge in three test solutions as blind duplicates using graphite furnace atomic absorption spectrometry (GF-AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES) or induced coupled plasma-mass spectrometry (ICP-MS). Statistical analysis revealed that the trueness, repeatability and reproducibility were 98-107%, 1.7-7.5% and 2.0-18.8% by using GF-AAS and ICP-OES. The performance of these methods is sufficient for testing the specifications. The performance parameters of ICP-MS were 99-106%, 0.7-2.2% and 2.2-10.5%, respectively. ICP-MS is available as an alternative measuring method. However, in some laboratories, the quantitative values of Sb were higher than the addition levels. We found that Sb in working solutions is absorbed on glass vessels. Careful control of concentration in working solutions is required for Sb analysis.

Germanium in ginseng is low and causes no sodium and water retention or renal toxicity in the diuretic-resistant rats.

Ginseng preparations contain high concentrations of germanium (Ge), which was reported to contribute to diuretic resistance or renal failure. However, Ge content in ginseng and the influence on renal functions remain unclear. Forty rats were randomly divided into control group, low, moderate, and high Ge ginseng-treated group and observed for 25 days. Daily urine, renal functions, and serum and urine electrolytics were measured. Ge retention in the organs and renal histological changes were also evaluated. Ge content ranged from 0.007 to 0.450 µg/g in various ginseng samples. Four groups showed no difference in the daily urine output, glomerular filtration rate, urinary electrolytes excretions, 24 h-urine protein, as well as plasma and urine urea nitrogen, creatinine, osmotic pressure, and pH values. Ge did not cause any renal pathological effects in this study. No Na and water retention was detected in the ginseng-treated groups. Ge retention in various organs was found highest in spleen, followed by the kidney, liver, lung, stomach, heart, and pancreas. The total Ge contents in various ginsengs were low, and ginseng treatment did not affect renal functions or cause renal histological changes.