Atmospheric depositional fluxes of cosmogenic <Superscript>32</Superscript>P, <Superscript>33</Superscript>P and <Superscript>7</Superscript>Be in the Sevastopol region

⁹⁰Y was separated from ⁹⁰Sr using an extraction chromatographic resin consisting of 4, 4′(5′)-bis-t-butylcyclohexano-18-crown-6 (DtBuCH₁₈C₆), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (C₂mimNTf₂), and a polymer (Amberlite XAD-7). Ionic liquid was introduced into the column to improve the separation efficiency. The column showed an excellent performance for the separation of Y from Sr. After the separation, the ratio of ⁹⁰Sr/⁹⁰Y was <2.0 × 10^?5; the column was recycled for >18 times. This study provides preliminary results on columns to produce ⁹⁰Y with a high purity in radiopharmaceuticals.     

Preparation of <Superscript>95m</Superscript>Tc radiotracer

Several procedures for preparation of the ^95mTc radiotracer following irradiation of a thin Mo target with deuterons were tested. The procedures consisting of alkaline-oxidative fusion of the irradiated target in a mixture of Na₂O₂ + NaOH and subsequent liquid–liquid extraction with 2-butanone, and acid decomposition of the target in a mixture of H₂SO₄ + HNO₃ followed by extraction chromatography with PAN-Aliquat 336 composite material appeared suitable for the given purpose.     

Simultaneous measurements of cosmogenic radionuclides <Superscript>32</Superscript>P, <Superscript>33</Superscript>P and <Superscript>7</Superscript>Be in dissolved and particulate forms in the upper ocean

A technique to determine concentrations of ³²P, ³³P and ⁷Be in dissolved and particulate forms, in the upper ocean was developed. By using a large volume in situ filtration and concentration system (LV-FiCS), several tons of seawater at different depths were filtered concurrently through two kinds of filters. The dissolved radionuclides were concentrated onto adsorbents in the LV-FiCS. The radionuclides obtained were further purified by precipitation and ion-exchange chromatography, and quantified by gamma-spectrometry and ultra-low level liquid scintillation counter measurements. The technique was used with good results in a coastal area of Ibaraki, Japan.     

Direct low-energy measurement of <Superscript>37</Superscript>Ar and <Superscript>127</Superscript>Xe in a radiotracer gas using low-background proportional counters

A radiotracer gas with a blend of ³⁷Ar and ¹²⁷Xe was created for a gas migration experiment and was characterized at Pacific Northwest National Laboratory using ultra-low-background proportional counters. This paper describes the direct low-energy measurement of ³⁷Ar and ¹²⁷Xe in a dual-isotope sample. Using this low-energy technique, the dual-isotope radiotracer gas was determined to have activity concentrations of 483 Bq/cc and 1435 Bq/cc for ³⁷Ar and ¹²⁷Xe, respectively, and a ratio of 1:3 on the reference date of 7/11/2016.     

Changes of decay rates of radioactive <Superscript>111</Superscript>In and <Superscript>32</Superscript>P induced by mechanic motion

The changes of decay rates of radionuclide 111in (electron capture) and 32p (β decay) induced by external mechanic motion are studied. The results indicate that, in the external circular rotation in clockwise and anticlockwise centrifuge on Northern Hemisphere (radius 8 cm, 2000 r/min), the half life of 111in compared with the referred (2.83 d) is decreased at 2.83% and increased at 1.77%, respectively; the half life of 32P compared with the referred (14.29 d) is decreased at 3.78% and increased at 1.75%, respectively. When the clockwise and anticlockwise rotations increase to 4000 r/min, the half life of 111in is decreased at 11.31% and increased at 6.36%, respectively; the half life of 32P is decreased at 10.08% and increased at 4.34%, respectively. When the circular rotation is removed, the decay rates of 111in and 32P return back to the referred, respectively. It is found that the external circular rotations in clockwise and anticlockwise centrifuge selectively increased and decreased the decay rates of 111in and 32p, respectively, and the effects are strongly dependent on the strength of circular rotation. It is suggested that these effects may be caused by the chiral interaction.     

Novel methodology for the study of mercury methylation and reduction in sediments and water using <Superscript>197</Superscript>Hg radiotracer

Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H₂SO₄ or HCl were evaluated in freshwater sediments using ¹⁹⁷Hg radiotracer. Values obtained for the ¹⁹⁷Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of ¹⁹⁷Hg²⁺ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg²⁺ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg²⁺ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H₂SO₄ method is recommended, since it is free from these interferences. ¹⁹⁷Hg radiotracer (T _1/2 = 2.673 d) has a production rate that is about 50 times higher than that of ²⁰³Hg (T _1/2 = 46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to ²⁰³Hg when it is used it in short-term experiments and produced by the irradiation of ¹⁹⁶Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the ¹⁹⁶Hg isotope is increased, the specific activity of the ¹⁹⁷Hg tracer can be significantly improved. In the present work, ¹⁹⁷Hg tracer was produced from mercury 51.58% enriched in the ¹⁹⁶Hg isotope, and a 340-fold increase in specific activity with respect to natural mercury targets was obtained. When this high specific activity tracer is employed, mercury methylation and reduction experiments with minimum mercury additions are feasible. Tracer recovery in methylation experiments (associated with Me¹⁹⁷Hg production from ¹⁹⁷Hg²⁺ spike, but also with Hg²⁺ contamination and Me¹⁹⁷Hg artefacts) with marine sediments was about 0.005% g⁻¹ WS (WS: wet sediment) after 20 h incubation with mercury additions of 0.05 ng g⁻¹ WS, which is far below natural mercury levels. In this case, the amount of Hg²⁺ reduced to Hg⁰ (expressed as the percent ¹⁹⁷Hg⁰ recovered with respect to the ¹⁹⁷Hg²⁺ added) varied from 0.13 to 1.6% g⁻¹ WS. Me¹⁹⁷Hg production from ¹⁹⁷Hg²⁺ spike after 20 h of incubation of freshwater sediment ranged from 0.02 to 0.13% g⁻¹ WS with mercury additions of 2.5 ng g⁻¹ WS, which is also far below natural levels. ¹⁹⁷Hg⁰ recoveries were low, 0.0058 ± 0.0013% g⁻¹ WS, but showed good reproducibility in five replicates. Me¹⁹⁷Hg production from ¹⁹⁷Hg²⁺ spiked in freshwater samples ranged from 0.1 to 0.3% over a period of three days with mercury additions of 10 ng L⁻¹. A detection limit of 0.05% for Me¹⁹⁷Hg production from ¹⁹⁷Hg²⁺ spike was obtained in seawater in a 25 h incubation experiment with mercury additions of 12 ng L⁻¹.     

<Superscript>1</Superscript>H and <Superscript>31</Superscript>P nuclear spin-lattice relaxation in C-phosphorylated oximes

The ¹H spin-lattice relaxation times of the proton-bearing groups and the ³¹P spin-lattice relaxation times in C-phosphorylated oximes R¹C(=NOH)P(=O)R²R³ (R¹ = Ph, R² = R³ = OMe; R¹ = Ph, R² = OMe, R³ = OCH²CH²Br; R¹ = PhCH², R² = R³ = OCHMe²) and dioxime R²P(=O)C(=NOH)(CH₂)₄C(=NOH)P(=O)R² (R = OMe) in DMSO-d₆ were measured. The characteristic reorientation times of the whole molecules were estimated using the measured values of the ¹H relaxation times and the results of semiempirical PM3 quantum chemical calculations of the molecular geometries. The reorientation times were used to identify the contributions of different relaxation mechanisms to the rate of ³¹P spin-lattice relaxation. The anisotropy of the chemical shielding of ³¹P nuclei was evaluated from the difference between the ³¹P relaxation rates measured at 101.27 and 161.92 MHz.     

Study of the cyclotron production of <Superscript>172</Superscript>Lu: an excellent radiotracer

¹⁷²Lu due to its suitable (T _1/2 = 6.7 days) and high detection sensitivity, is used as a radiotracer in different fields. ¹⁷²Lu appears to be suitable as a long-lived rare-earth tracer for compound labelling and biodistribution studies. In the present study, excitation functions via ¹⁷²Yb(p,n)¹⁷²Lu, ^natYb(p,xn)¹⁷²Lu, ¹⁷²Yb(d,2n)¹⁷²Lu and ^natYb(d,xn)¹⁷²Lu reactions were calculated by ALICE/91, ALICE/ASH and TALYS-1.2 codes. Deposition of ^natYb₂O₃ on Cu substrate was carried out via sedimentation method for the production of ¹⁷²Lu. Cementation separation process and liquid–liquid extraction (LLX) of no-carrier-added (nca) radiolutetium from irradiated ytterbium(III)oxide target hydrochloric solution was described using Na(Hg) amalgam, α-hydroxyisobutyric acid (α-HIB) and di-(2-ethylhexyl)phosphoric acid (HDEHP).     

Attempt to reduce <Superscript>239</Superscript>Pu and <Superscript>241</Superscript>Am uptake by wheat plantlets by application of inorganic fertilizers

Inorganic fertilizers are applied to reduce plant uptake of anthropogenic radionuclides, but scarce data are available for ²³⁹Pu and ²⁴¹Am. Wheat plantlets were grown in laboratory on limited amount of soil with ²³⁹Pu, ²⁴¹Am and different application rates of NPK and diammonium phosphate (DAP). As rates increased, the uptake of ²³⁹Pu and ²⁴¹Am to the whole plantlet also increased. It was higher for DAP than for NPK, (higher supply of P₂O₅ and NH₄ ⁺). Root content was higher than shoots for all experiences, suggesting low mobility within the plantlet. Root content increased with fertilizer rate, but practically no effect in shoots.     

Styrene oxide DNA adducts: quantitative determination using <Superscript>31</Superscript>P monitoring

The reaction of styrene oxide, a potential carcinogen in humans, with DNA constituents has been used to develop an improved method for quantification of DNA adducts. To enable monitoring of DNA adducts caused by xenobiotics at physiological relevant levels, a robust, reliable and powerful method based on monitoring of phosphorus in nucleotides is described. An efficient enzymatic digestion step and a sample-preconcentration procedure are essential, and enable separation of alkylated nucleotides from the large excess of native nucleotides. The adducts are detected by means of the phosphorus signal measured at mass m/z=31 with an inductively-coupled-plasma mass spectrometer. Bis(4-nitrophenyl)phosphate (BNPP) serves as internal standard for quantification of the adducts. The absolute limit of detection, 45 fmol, corresponds to detection of three modified nucleotides among 10⁷ native nucleotides (the calculation is based on use of 50 g calf thymus DNA). An adduct formation ratio at the DNA of 3.6 adducts per 1000 nucleotides was measured, which is 75% lower than for reaction with monomeric 2-deoxy-nucleotides. In addition, a substantial amount of phosphate adducts were detected, but in DNA the rate of phosphate formation was lower than with monomeric nucleotides. Most probably these adducts escaped unnoticed when ³¹P-post-labelling was employed.     

Separation of <Superscript>125</Superscript>IBZM and <Superscript>125</Superscript>ILIS using polyacrylamide-acrylic acid resin

Radioiodination of both S(−)BZM and LIS was carried out using n-bromosuccimide(NBS) as a mild oxidizing agent. The factors affecting on the radiochemical yield such as pH, reaction time, substrate concentration and oxidizing agent have been studied. The chromatographic separation of both ¹²⁵IBZM and ¹²⁵ILIS was carried out using HPLC and poly(acrylamide-acrylic acid) resin P(AAm-AA). The copolymer was prepared by a template polymerization of AA in aqueous solution on PAAm as a template polymer and in the presence of N,N-methylenebisacrylamide (NMBA) as a crosslinker using gamma rays as initiator. The purifications of tracers were carried out using prepared resin compared with TLC and HPLC. The effects of pH buffer, variable elution volumes, flow rate and temperature on the separation process of the resin efficiency have been studied.     

Assessment of <Superscript>210</Superscript>Po in foodstuffs consumed in Korea

²¹⁰Po in the daily diet in Korea was analyzed and the ingestion dose from an intake of ²¹⁰Po was estimated by considering the dietary habit of a Korean person. The ²¹⁰Po concentrations of a leafy vegetable (0.36 Bq·kg⁻¹ for lettuce) in the terrestrial food were higher than those of grain, whereas Chinese cabbage had a lesser ²¹⁰Po concentration (0.019 Bq·kg⁻¹). The ²¹⁰Po concentration of the animal product was similar to those detected in the grain and vegetable. The ²¹⁰Po concentrations in the shell and crustaceous were high from 19.1 to 33.0 Bq·kg⁻¹, however, its value fell in the overall range of the reported values. The effective dose from ²¹⁰Po for an adult from the Korean population was about 269.4 μSv·y⁻¹. Nearly 80% of the ingestion dose from the intake of ²¹⁰Po was attributed to the consumption of seafood. It suggests that the marine food ingestion is a critical pathway for natural ²¹⁰Po to the Korean population.     

Determination of <Superscript>151</Superscript>Sm and <Superscript>147</Superscript>Pm using liquid scintillation tracer methods

The long-lived rare earth isotopes ¹⁵¹Sm (90 years, β _max = 76.3 keV) and ¹⁴⁷Pm (2.62 years, β _max = 224.6 keV) are low-yield fission products that generally require lengthy separation procedures to isolate and count by their beta emissions. We will describe novel liquid scintillation counting techniques using radioactive tracers to determine radiochemical yields from an environmental matrix. The recovery of ¹⁵¹Sm is determined from the alpha decay (2.25 MeV) of ¹⁴⁷Sm in the natural Sm carrier and is in excellent agreement with the gravimetric recovery. The ¹⁴⁷Pm recovery is determined by the use of ¹⁴⁵Pm (17.7 years, EC) tracer, custom-produced at LANL using an isotopically enriched target of ¹⁴⁴Sm. We have determined the ¹⁴⁵Pm recovery both from the 37.4 keV k_α1 X-ray, and the electron-capture emissions by LSC. A comparison of these recovery methods is presented.     

Disequilibrium of dissolved <Superscript>234</Superscript>U/<Superscript>238</Superscript>U and <Superscript>210</Superscript>Po/<Superscript>210</Superscript>Pb in Greek rivers

For the first time, a radiological study for the dissolved ²³⁸U, ²³⁴U, ²¹⁰Pb and ²¹⁰Po was held in major Greek rivers across the country. ²³⁴U/²³⁸U activity ratios are above one in all samples and ²¹⁰Po/²¹⁰Pb activity ratios are respectively below the unit indicating the disequilibrium in the samples. Quite satisfactory correlations were observed among ²³⁴U and ²³⁸U as well as among ²¹⁰Po and ²¹⁰Pb values. Uranium isotopes were separated by ion exchange and electroplated on stainless steel plates. ²¹⁰Po was spontaneously deposited on nickel plates, while ²¹⁰Pb was indirectly determined through the ingrowth of ²¹⁰Po. The sources were measured by a-spectrometry.     

Structural features of acidic fluorophosphatozirconates (hafnates) from the <Superscript>19</Superscript>F, <Superscript>31</Superscript>P, <Superscript>1</Superscript>H NMR data

Fluorophosphatometallates with the composition K₃H₃Zr₃F₃(PO₄)₅, Rb₃H₃Zr₃F₃(PO₄)₅, Rb₃H₃Hf₃F₃(PO₄)₅, CsH₂Hf₂F₂(PO₄)₃?2H₂O are studied by ³¹P, ¹⁹F, and ¹H NMR. It is found that protons enter in the composition of hydrophosphate groups and fluorine atoms occupy the terminal sites in the tetravalent metal environment. Schemes of the crystal structure of fluorophosphatometallates are proposed. It is established that in CsH₂Hf₂F₂(PO₄)₃?2H₂O water molecules are bonded to the phosphate group proton via a strong hydrogen bond and are characterized by a low energy barrier of molecular motions.     

<Superscript>103</Superscript>Rh, <Superscript>17</Superscript>O,and <Superscript>31</Superscript>P NMR study of Rh(III) complex formation in acidic sulfate-phosphate media

Rhodium(III) complex formation with phosphoric acid in strong acidic solutions has been studied by ¹⁰³Rh, ¹⁷O, and ³¹P NMR. Phosphoric acid is mainly coordinated to rhodium as a monodentate terminal HPO₄²⁻ ion, while the coordinated phosphate ion accounts for no more than 7%.     

Determination of <Superscript>3</Superscript>H, <Superscript>226</Superscript>Ra, <Superscript>222</Superscript>Rn and <Superscript>238</Superscript>U in Austrian ground- and drinking water

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.     

Non-destructive assay technique for the determination of <Superscript>238</Superscript>U/<Superscript>232</Superscript>Th ratio in the mixed oxides of uranium and thorium using prompt gamma-ray neutron activation

A non-destructive assay technique based on prompt gamma-ray neutron activation analysis for the determination of ²³⁸U to ²³²Th ratio in the mixed oxide fuel materials has been established. The method uses closely spaced high energy gamma-rays in the region of 4000 keV to 4150 keV enabling it to be applied for samples of any geometry and thickness without having any correction for gamma-ray attenuations and detection efficiencies.