The concentration of <Superscript>238</Superscript>U and the levels of gross radioactivity in surface waters of the Van Lake (Turkey)

Gross α and gross β activities and ²³⁸U concentrations were determined in 18 surface water samples collected from Van Lake. The instrumentations used to count the gross α and gross β activities and to determine the ²³⁸U concentrations were α/β counter of the multi-detector low background system (PIC-MPC-9604) and Inductively Coupled Plasma-Mass Spectrometry (Thermo Scientific Element 2), respectively. Concentrations ranging from 0.001 to 0.021 Bq L⁻¹ and from 0.111 to 2.794 Bq L⁻¹ were observed for the gross α and β activities in surface waters, respectively. For all samples the gross β activities were higher than the corresponding gross α activities. The results indicated that the gross α radioactive contamination in water samples was lower than recommended values for the guideline of drinking waters and most of the gross β activities in water samples were higher than those in the same procedure. The ²³⁸U concentrations ranged from 74.49 to 113.2 μg L⁻¹ in surface waters. The obtained results have showed that ²³⁸U concentrations are higher than guideline values for uranium.     

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.     

Impact of season and location on the natural radioactivity in marine macroalgae (<Emphasis Type="Italic">Gracilaria edulis)</Emphasis> of coastal Tamil Nadu,India

Gracilaria edulis, an edible red marine macro algae from three high background radiation areas (Arockiapuram, Kadiapattinam and Kurumpanai) on the southwest coast of Tamil Nadu, and one low background radiation area (Mandapam) on the southeast coast of Tamil Nadu, in India, were studied for variations in average gross alpha and beta radiation activities. Significant variations in average gross beta activities were observed while alpha activities showed only marginal variation. The average gross alpha activity was recorded high (61.51 Bq kg ⁻¹) during the post southwest monsoon season, while it recorded lowest (25.48 Bq kg ⁻¹) during the post northeast monsoon season. Average gross beta activity varied between seasons with the lowest level (211.55 Bq Kg⁻¹) during post southwest monsoon season and the highest (413.33 Bq kg ⁻¹) during post northeast monsoon season. Among the four locations, the gross alpha activity was high (70.95 ± 26.74 Bq Kg⁻¹) in Arockiapuram and low (18.74 ± 6.32 Bq Kg⁻¹) in Mandapam, while the gross beta activity was high (442.25 ± 168.53 Bq Kg⁻¹) in Kurumpanai and low (158.63 ± 34.37 Bq Kg⁻¹) in Mandapam. Average gross alpha activity in G. edulis was found significantly varying in terms of locations, while average gross beta activity for the same species recorded significant seasonal variation.     

Quinolinephosphomolybdate as ion exchanger: synthesis,characterization, and application in separation of <Superscript>90</Superscript>Y from <Superscript>90</Superscript>Sr

An inorganic ion exchanger, quinolinephosphomolybdate has been synthesized and characterized by elemental analysis, infrared (IR) and X-ray diffraction (XRD) spectroscopy. This compound is highly stable toward thermal, chemical and radiation dose. This has been employed in the separation of carrier-free ⁹⁰Y from its parent ⁹⁰Sr from an equilibrium mixture. The absorbed daughter was recovered by using 0.0284 mol L⁻¹ ascorbic acid solutions at pH 5.0 as eluting agent.     

<Superscript>3</Superscript>H and <Superscript>90</Superscript>Sr in urine radiobioassay intercomparison results from the intercomparison studies program at Oak Ridge National Laboratory: statistical analysis of laboratory performance

The Intercomparison Studies Program (ISP) at the Oak Ridge National Laboratory (ORNL, Oak Ridge, TN USA) provides natural-matrix human urine quality-assurance/quality-control (QA/QC) samples to radiobioassay analysis laboratories. Samples are provided to these laboratories as “single-blind” or “double-blind” unknowns, spiked with radioactive-solution standards at “low” levels (e.g., 0.7–7 Bq g⁻¹ for ³H and 0.7–7 Bq kg⁻¹ for ⁹⁰Sr). Participants use the results as a tool for self-evaluation and a measure of performance. In this paper, sample preparation and the results of testing during the years 2001–2005 for ³H and ⁹⁰Sr are presented and discussed.     

Preparation and preliminary evaluation of <Superscript>211</Superscript>At-labeled amidobisphophonates

In this paper, 3-amino-1-hydroxypropylidene-1,1-bisphosphonate(APB), a amidobisphophonate was synthesized and labeled with the α-emitter ²¹¹At by an indirect method using N-succinimidyl 5-(tributylstannyl)-3-pyridinecarboxylate (SPC) as a bi-functional linker, and the conjugated amidobisphophonate (²¹¹At-SAPC-APB) was preliminarily evaluated in vitro and in vivo by comparison with free astatide (²¹¹At⁻) and ^99mTc-MDP. 3-amino-1-hydroxypropylidene-1,1-bisphosphonate(APB) was prepared using β-alanine as the starting material. With SPC bi-functional linker, APB was conjugated with ²¹¹At in a labeling yield of 80–90% with radiochemical purity of more than 99%. The conjugated amidobisphophonate (²¹¹At-SAPC-APB) exhibited considerable stability in vitro, in that the radiochemical purity of ²¹¹At-SAPC-APB was still more than 98% in 0.1 mol/L PBS (pH 7.6) or in fetal calf serum, even stayed for 24 h at room temperature (RT). Biodistribution of ²¹¹At-SAPC-APB was investigated in NIH strain mice by I.V injection. The results showed that ²¹¹At-SAPC-APB could rapidly locate in shank, with the maximum uptake of 23.70 ± 2.29% I.D/g at 6 h, earlier than that of ^99mTc-MDP at 12 h, and stayed in the bone for long time. Moreover, ²¹¹At-SAPC-APB uptake in some key organs or tissues, especially in thyriod, stomach, lung and spleen, was much less than that of free astatide (²¹¹At⁻), implying that ²¹¹At-SAPC-APB was constantly stable in vivo as well as in vitro. These results indicated that ²¹¹At-SAPC-APB will be a suitable candidate for the targeted radiotherapy of bone metastases and should be further investigated.     

Determination of <Superscript>40</Superscript>K, <Superscript>226</Superscript>Ra and <Superscript>232</Superscript>Th concentration and radiation dose assessment in titanium enamel frits use in polishing household utensils in Ghana

As part of monitoring the exposure of the Ghanaian public to natural radioactivity, radioactivity concentrations in titanium enamel frits use for coating, spraying and decorating steel bowls were investigated. Samples collected from Ghana Utensil Manufacturing Company in Ghana were analyzed using γ-ray spectrometry with a high purity germanium detector. The samples were found to contain an average absorbed dose rate of 509.38 nGy h⁻¹, while an average annual effective dose was calculated to be 2.50 mSv.     

Polymer-coated magnetic nanoparticles for rapid bioassay of <Superscript>90</Superscript>Sr in human urine samples

A rapid bioassay for ⁹⁰Sr was developed involving preconcentration of ⁹⁰Sr/⁹⁰Y from human urine samples with a cation exchange polymer (poly–acrylamido–methyl–propanesulfonic acid) coated onto magnetic nanoparticles, followed by selective elution of ⁹⁰Sr (over ⁹⁰Y) with phosphate for determination by liquid scintillation analysis. The minimum detectable activity for this method (4.9 ± 0.5 Bq/L) is lower than the required sensitivity of 19 Bq/L for ⁹⁰Sr in human urine samples, as defined in the requirements for radiation emergency bioassay techniques for the public and first responders based on the dose threshold for possible medical attention recommended by the International Commission on Radiological Protection. The relative bias was 9.2%, the relative precision was 3.2%, and the linear dynamic range covered 12–600 Bq/L. This simple and rapid bioassay method is found to be in compliance with the HPS ANSI N13.30 performance criteria for radiobioassay.     

Separation and determination of <Superscript>90</Superscript>Sr in low- and intermediate-level radioactive wastes using extraction chromatography and LSC

A methodology for the determination of ⁹⁰Sr in low- and intermediate-level radioactive wastes from nuclear power plants is presented in this work. It is a part of a methodology developed for the sequential radiochemical separation of radionuclides difficult-to-measure directly by gamma spectrometry in these radioactive wastes. The separation procedure was carried out using precipitation and extraction chromatography with Sr Resin, from Eichrom and the ⁹⁰Sr was measured by liquid scintillation counting (LSC). Optimum conditions for the pretreatment, separation and LSC measurements were determined using simulated samples, which were prepared using standard solutions and carriers. The procedure showed to be rapid and achieved a good chemical yield, in the range 60–90%, and a detection limit of 6.0 × 10⁻⁴ Bq g⁻¹. The method was also tested by participation in a national intercomparison program, with aqueous samples, with good agreement of results.     

Pharmacokinetics,tissue distribution and excretion of a recombinant fusion protein <Superscript>125</Superscript>I-rhTNT-IL2

This study examined the tissues distribution and pharmacokinetics of rhTNT-IL2, a fusion protein, in rats and macaques after iv. injection. The rhTNT-IL2 was labeled with ¹²⁵I. The ¹²⁵I-rhTNT-IL2 was administered into rats and macaques at a dose of 250 μg·kg⁻¹ and 125 μg·kg⁻¹, respectively. Upon administration, rhTNT-IL2 declined in tri-exponentially with the half-lives of 1.78 h (T _1/2α), 25.06 h (T _1/2β), 114.19 h (T _1/2γ) for rats and 1.87 h (T _1/2α), 9.82 h (T _1/2β), 43.17 h (T _1/2γ) for macaques. The fraction of ¹²⁵I-rhTNT-IL2 excreted in feces was low (about 1%), while the majority of ¹²⁵I-rhTN-IL2 was excreted in urine. The tissue distributions showed that the liver, spleen and heart were major organs for deposition of the fusion protein in rats and macaques in 48-hour post-injection, and the fusion protein could not penetrate through blood brain barrier.     

Distribution of <Superscript>137</Superscript>Cs, <Superscript>40</Superscript>K, <Superscript>232</Superscript>Th and <Superscript>238</Superscript>U in coastal marine sediments of Margarita Island,Venezuela

This work presents the results of ¹³⁷Cs, ⁴⁰K, ²³²Th and ²³⁸U concentration (Bq kg⁻¹) values in coastal marine sediments collected from 38 sites along the coastline of the island of Margarita, Venezuela. The purpose was to determine baseline values for these radionuclides in surface marine sediments and to detect if there were any anomalously high concentration values. Only three of the 38 sediments analyzed had measurable values above the detection limit of 0.9 Bq kg⁻¹ for ¹³⁷Cs and the highest only being 1.4 Bq kg⁻¹. While, the concentration (Bq kg⁻¹) ranges for the primordial radionuclides, ⁴⁰K, ²³²Th and ²³⁸U were as follows: 12.2–211.7, <1.5–9.8 and <4.4–20.7, respectively. These concentration ranges for the primordial radionuclides can be considered as baseline values for surface marine sediments for areas that are considered not polluted by man or contaminated by nature. Finally, the concentration range of ¹³⁷Cs can also be employed as baseline values, which only seem to have been the result of the atmospheric testing of nuclear weapons in the past.     

Radioactivity levels of <Superscript>238</Superscript>U and <Superscript>232</Superscript>Th,the α and β activities and associated dose rates from surface soil in Ulu Tiram,Malaysia

A survey was carried out to determine terrestrial gammaradiation dose rates, the concentration level of ²³⁸U and ²³²Th and α and β activities for the surface soil in Ulu Tiram, Malaysia A 125 measurements were performed using a NaI(T1) gamma-ray detector with crystal size of 1″ × 1″ on 15 soil samples collected from the site area about 102 km^{2 238}U and ²³²Th concentrations were determined in soils by using hyper pure germanium (HPGe) gamma-ray spectrometry. The activity of α and β from the surface soil was counted by using alpha beta counting system. The average value of ²³⁸U and ²³²Th concentrations in soil samples collected are 3.63±0.39 ppm within the range of 1.74±0.20 to 4.58±0.48 and 43.00±2.31 ppm within the range of 10.68±0.76 to 82 10±4.01 ppm, respectively. The average estimate of α and β activity in soil samples collected are 0.65±0.09 Bqg⁻¹ and 0.68±0.08 Bqg⁻¹, respectively. The average of terrestrial gamma-radiation dose rates measured in Ulu Tiram was found to be 200 nGy h⁻¹, within the range of 96 to 409 nGy h⁻¹. The population weighted outdoor annual effective dose was 1.2 mSv.     

Natural <Superscript>3</Superscript>H radioactivity analysis in groundwater and estimation of committed effective dose due to groundwater ingestion in Varahi and Markandeya river basins,Karnataka State,India

The present study aimed at the assessment of natural tritium radioactivity in groundwater, being used for domestic and irrigation purposes in Varahi and Markandeya river basins. The study also intended to assess human health risk by estimating committed effective dose due to groundwater ingestion in the study area, taking into consideration the obtained tritium activity concentrations and annual water consumption. Tritium concentration of groundwater samples from the Varahi and Markandeya river basins were determined by liquid scintillation counting and the results laid in the range of 1.95 ± 0.25 to 11.35 ± 0.44 TU and 1.49 ± 0.75 to 9.17 ± 1.13 TU in Varahi and Markandeya river basins, respectively. Majority of the samples from Varahi (46.67%) and Markandeya (62.5%) river basins belong to modern water category aged between 5 and 10 years, while the remaining 53.33% and 37.5% of the samples from Varahi and Markandeya river basins respectively belong to sub-modern water with modern recharge, significantly influenced by precipitation and river inflowing/sea water intrusion. The effective committed dose for general public consumption considering the highest concentration value of 0.02 μSv year⁻¹, which is very negligible compared to EPA (0.04 mSv year⁻¹), WHO (0.1 mSv year⁻¹), ICRP (1.0 mSv year⁻¹) and UNSCEAR (2.4 mSv year⁻¹) recommended dose limits, should not mean any additional health risk for the population living nearby.     

Levels of <Superscript>232</Superscript>Th activity in the South Adriatic Sea marine environment of Montenegro

²³²Th activities in the South Adriatic Sea-water, surface sediment, mud with detritus, seagrass (Posidonia oceanica) samples, and the mullet (Mugilidae) species Mugil cephalus, as well as soil and sand from the Montenegrin Coast, were measured using the six-crystal spectrometer PRIPYAT-2M, which has relatively high detection efficiency and a good sensitivity, and allows a short acquisition time, and measuring samples of any shape, without preliminary preparation and calibration measurements for different sample geometries. An average ²³²Th activity concentration in surface soil layer is found to be 40.33 Bq kg⁻¹, while in sand—4.7 Bq kg⁻¹. The absorbed dose rate in air due to ²³²Th gamma radiation from surface soil layer ranged from 11.76 to 63.39 nGy h⁻¹, with a mean of 24.06 nGy h⁻¹. Corresponding average annual effective dose rate has been found to be 0.03 mSv y⁻¹. The absorbed dose rates due to the thorium gamma radiation in air at 1 m above sand surface on the Montenegrin beaches have been found to be from 0.41 to 9.08 nGy h⁻¹, while annual effective dose rates ranged from 0.0005 to 0.011 mSv y⁻¹. ²³²Th activity concentration in seawater ranged from 0.06 to 0.22 Bq L⁻¹, as in the mullet (Mugil cephalus) whole individuals from 0.63 to 1.67 Bq kg⁻¹. Annual intake of ²³²Th by human consumers of this fish species has been estimated to provide an effective dose of about 0.003 mSv y⁻¹.     

Technology of DTPA and immunoglobulins conjugation and their attachment to <Superscript>90</Superscript>Y and <Superscript>177</Superscript>Lu radionuclides

The aim of the study of labeling of ligand–antibody conjugates was to find optimal conditions of preparing of these conjugates and appropriate radioactivity of selected nuclide for applications in nuclear medicine. Conjugation of the γ-immunoglobulin G (human or bovine IgG, polyclonal antibodies) and bifunctional chelating agent, diethylenetriaminepentaacetic acid dianhydride (cDTPAA), was carried out. Various values of the cDTPAA/antibody ratio, the weight concentration of polyclonal or monoclonal antibodies (MEM-97) and buffers were used. Further, the labeling conditions of the DTPA–IgG conjugate by radionuclides ⁹⁰Y and ¹⁷⁷Lu were optimized, and the labeling yield and the conjugation ratio of prepared radionuclide–DTPA–IgG conjugates was determined. Optimal incubation time of the immunoglobulin conjugation was obtained at 30 min from mixing of individual components. The labeling yield of radionuclide–DTPA–antibody conjugate higher than 95% was achieved. Higher values of conjugation ratio of radionuclide–DTPA–antibody conjugate were achieved in 0.1 mol L⁻¹ carbonate buffer, pH 8.5, and the 0.1 mol L⁻¹ carbonate buffer is suitable for studied conjugation systems. This study showed that the labeling yield as well as the conjugation ratio of tested systems depend on the amount of antibody substance, bifunctional chelating agent/antibody molar ratio and pH value of the buffer used.     

Biosorptive behavior of mango (<Emphasis Type="Italic">Mangifera indica</Emphasis>) and neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) barks for <Superscript>134</Superscript>Cs from aqueous solutions: A radiotracer study

The role of dead biomasses viz., mango (Mangifera indica) and neem (Azadirachta indica) bark samples are assessed in the removal behavior of, one of important fission fragments, Cs(I) from aqueous solutions employing a radiotracer technique. The batch type studies were carried out to obtain various physico-chemical data. It is to be noted that the increase in sorptive concentration (from 1.0·10⁻⁸ to 1.0·10⁻² mol·dm⁻³), temperature (from 298 to 328 K) and pH (2.6 to 10.3) apparently favor the uptake of Cs(I) by these two bark samples. The concentration dependence data obeyed Freundlich adsorption isotherm and the uptake follows first order rate law. Thermodynamic data evaluation and desorption experiments reveal the adsorption to be irreversible and endothermic in nature proceeding through ion-exchange and surface complexation for both dead biomasses. Both bark samples showed a fairly good radiation stability in respect of adsorption uptake of Cs(I) when irradiated with a 300 mCi (Ra-Be) neutron source having an integral neutron flux of ∼3.85·10⁶ n·cm⁻²·s⁻¹ and associated with a nominal γ-dose of ∼1.72 Gy·h⁻¹.     

Synthesis of electrospun BaSrTiO<Subscript>3</Subscript>/PVP nanofibers

Ba_1−x Sr _x TiO₃(x = 0–0.5, BST) nanofibers with diameters of 150–210 nm were prepared by using electrospun BST/polyvinylpyrrolidone (PVP) composite fibers by calcination for 2 h at temperatures in the range of 650–800 °C in air. The morphology and crystal structure of calcined BST/PVP nanofibers were characterized as functions of calcination temperature and Sr content with an aid of XRD, FT-IR, and TEM. Although several unknown XRD peaks were detected when the fibers were calcined at temperatures less than 750 °C, they disappeared with increasing the temperature (above 750 °C) due to its thermal decomposition and complete reaction in the formation of BST. In addition, the FT-IR studies of BST/PVP fibers revealed that the intensities of the O–H stretching vibration bands (at 3430 and 1425 cm⁻¹) became weaker with increasing the calcination temperature and a broad band at 540 cm⁻¹, Ti–O vibration, appeared sharper and narrower after calcination above 750 °C due to the formation of metal oxide bonds. However, no effect of Sr content on the crystal structure of the composites was detected.     

Bioaccumulation and biosorption of stable strontium and <Superscript>90</Superscript>Sr by <Emphasis Type="Italic">Oscillatoria homogenea</Emphasis> cyanobacterium

The ability of living filamentous cells of the cyanobacterium Oscillatoria homogenea to separate stable strontium and ⁹⁰Sr from aqueous solution is demonstrated in this study. On a basis of filamentous cell biovolume, the removal were 43.78 nM·ml·(mm³)⁻¹ and 3129.48 mBq·ml·(mm³)⁻¹ after 240 hour incubation. The optimum pH for strontium uptake is 9±0.3. The increasing biovolume of the blue-green alga elevates sorption. In the liquid culture containing 21.2 mm³·ml⁻¹ filamentous cells and 1000 nM·ml⁻¹ initial strontium concentration, the maximum strontium removal was 455.34 nM·ml·(mm³)⁻¹. At 1200 Lux illumination, the maximum removal value was 58.62 nM·ml·(mm³)⁻¹, and at the initial strontium concentration of 6590 nM·ml⁻¹, 235.40 nM·ml·(mm³)⁻¹ removal was observed. The experimental data fitted to Langmuir isotherm and the model parameters and correlation coefficient (R ²) were q _max = 7.143 μg·(mm³)⁻¹, b = 0.003 and 0.99, respectively.     

Analytical investigation of energy spectrums of beta rays emitted from <Superscript>90</Superscript>Sr and <Superscript>204</Superscript>Tl radioisotopes

The energy spectra of beta rays emitted from ⁹⁰Sr and ²⁰⁴Tl radioisotopes were obtained by using a silicon surface barrier detector with a 1000 μm depleted layer and 50 mm² effective area. The detector response function is interpreted by making use of range distributions of mono-energetic electrons in matter and by assuming a linear energy loss along the range in the depleted layer of the detector. An analytical expression is given for pulse height distribution obtained in the surface barrier detector. A good agreement is observed between the experimental results and theoretical interpretation.     

A novel electrochemical <Superscript>99</Superscript>Mo/<Superscript>99m</Superscript>Tc generator

A novel electrochemical process to avail clinical grade ^99mTc from (n,γ)⁹⁹Mo has been demonstrated. The electrochemical parameters were optimized to maximize the ^99mTc yield with minimal ⁹⁹Mo contamination. ⁹⁹Mo/^99mTc generators containing up to 29.6 GBq (800 mCi) ⁹⁹Mo were developed and their performance were extensively evaluated for 10 days without changing the operating conditions. Very high radioactive concentration of ^99mTcO₄ ⁻ of acceptable quality, commensurate with hospital radiopharmacy requirements could be availed from the system with >90% yield. The compatibility of the product for the formulation of ^99mTc labeled radiopharmaceuticals such as ^99mTc-DMSA and ^99mTc-EC was found to be satisfactory in terms of high labeling yields. The proposed route represents an important step for enhancing the scope of accessing clinical grade ^99mTc from low specific activity (n, γ)⁹⁹Mo.