Instrumental neutron activation analysis of spherule samples recovered from the Pacific ocean sea sediment and Antarctic ice sheet

Chemical compositions of spherules separated from deep sea sediment dredged off Hawaiian islands and from Antarctic ice were measured by instrumental neutron activation analysis (INAA) using Kyoto University Reactor (KUR). Iron, cobalt, nickel, iridium, scandium and manganese contents in those spherules were determined to be 19.3–97.7%, 23–4370 mg·kg⁻¹, 0.08–7.04%, 0.84–35.4 mg·kg⁻¹, 1.4–44.3 mg·kg⁻¹ and 93.4 mg·kg⁻¹–7.2 %, respectively, and compared with each other. Particularly, iridium was detected in seven spherules among fourteen from Hawaii, but only one spherule among twenty-two from Antarctic, and those spherules turned out to be extraterrestrial in origin. However, it was shown that there was little difference in characteristics of elemental contents between both kinds of spherules, except for Ir-detected spherules.     

Elevated uptake of Th and U by netted chain fern (<Emphasis Type="Italic">Woodwardia areolata</Emphasis>)

We assessed the ability of netted chain fern (Woodwardia areolata) to uptake U and Th from wetland soils on the U.S. Department of Energy’s Savannah River Site in South Carolina. Netted chain fern had the highest Th and U concentrations of all plants collected from the wetland. Ferns grown in contaminated soil (329 mg·kg⁻¹ Th, 44 mg·kg⁻¹ U) in a greenhouse contained 6.4 mg·kg⁻¹ Th and 5.3 mg·kg⁻¹ U compared with 0.13 mg·kg⁻¹ Th and 0.035 mg·kg⁻¹ U in Bermuda grass (Cynodon dactylon). Netted chain fern has potential for the phytoremediation of soils contaminated with Th and U.     

Instrumental neutron activation analysis of monomineral fractions of sulfide minerals and quartzes

A method has been worked out of multi-elemental instrumental neutron-activation analysis INAA of small weights some mg of monomineral fractions of sulfide minerals pyrites, galenites, chalcopyrites, arsenopyrites, bornites, chalcosines and quartzes. The samples were irradiated in a nuclear reactor under a flux of 1.3·10¹³ n·cm⁻²·s⁻¹. For measuring the gamma radiation of the exposed samples Ge(Li) gamma-spectrometers with semiconductor detectors were used. Determined in sulfide monofractions were the elements: Co, Sc, Ag, Se, Sb, Cr, Fe, Zr; rare-earth elements: Ce, Sm, Eu and others at content levels of 10⁻¹−10⁻⁴%. In quartzes they were: Mn, Na, Sb, Cr, Sc, Fe, Co at content levels of 10⁻⁵−10⁻⁷% and Au to n×10⁻⁹%. A special method has been worked out for the determination of In in sulfides with the irradiation of samples in a cadmium screen. An example is cited of using the method for studying some peculiar features of the genetics of copper pyrite deposits. The data on the distribution of admixture elements in sulfide monofractions produced in this work made it possible to conclude that the oreformation in the deposits has a stage-by-stage character.     

Neutron activation analysis of cadmium in Jamaican soils

A procedure for the instrumental neutron activation analysis of Cd in soils with relatively high Cd content and possible inteferences is reported. Cadmium concentrations in Jamaican soils above 4 mg·kg⁻¹ can now be reliably determined by multielemental instrumental activation analysis with an accuracy ±10% and the reasonably high throughput of 30 samples per day. Over 600 geochemical survey samples were analysed for Cd along with some 20 other long-lived elements.     

Study of trace impurities in heroin by neutron activation analysis

Sixty-two heroin samples were analyzed for their contents of 15 trace elements (Au, Ba, Br, Ca, Ce, Co, Cr, Fe, La, Na, Sb, Sc, Sm, Th, and Zn) by neutron activation analysis (NAA). Large variations of elemental concentrations between samples were found to possess statistical significance. Of all the elements calcium was the most abundant element, followed by zinc and sodium. The concentrations of Au, Ce, Co, La, Sb, Sc, Sm, and Th in all the samples were below 1 mg·g⁻¹. Classification of these heroin samples was achieved by the application of hierarchical cluster analysis. The results show that NAA can provide useful information on the origin of the illicit drugs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Determination of chromium in blood by neutron activation analysis

A procedure for the determination of chromium in blood has been developed with a sensitivity of 5×10⁻³ μg Cr. Dried blood was irradiated with a neutron flux of 10¹² n·cm⁻²·sec⁻¹ in the VVRS reactor for 4 weeks, then the sample was mineralized and the chromium isolated by extraction as perchromic acid. The determination of the chromium content was accomplished by measuring the 0.32 MeV gamma energy of⁵¹Cr. In order to make correction for the interfering reaction⁵⁴Fe(n,α)⁵¹Cr, the formation of chromium from high-purity iron was investigated. The chromium content of the blood samples was between 1.03×10⁻² and 5.2×10⁻² ppm Cr.     

Determination of trace elements in water by non-destructive neutron activation

A systematic study was undertaken in order to find out which of the most relevant elements can be determined in water under normal conditions by non-destructive neutron activation simultaneously using a suitable monostandard method. Standardized water samples as well as natural water of different kind were used, brought to dryness by freeze-drying and irradiated in quartz at a neutron flux of 10¹⁴ cm⁻² s⁻¹ for 1 day. The trace element content in quartz ampoules of different origin was determined separately. The following elements are discussed in detail including possible interferences: As, Au, Br, Ca, Cd, Co, Cr, Cu, Eu, Fe, Hg, K, La, Mo, Na, Ni, Sb, Sc, Se, U, Zn. Presented at the Euroanalysis II Conference, Budapest, 25–30. Aug. 1975.     

Characterization of Brazilian commercial milks by instrumental neutron activation analysis

Aiming at the determination of toxic and essential elements in Brazilian commercial bovine milk, 25 ultra high temperature (UHT) milk samples were acquired in the local market of Piracicaba, SP. The samples were freeze-dried and analyzed by instrumental neutron activation analysis (INAA) allowing the determination of Br, Ca, Co, Cs, Fe, K, Na, Rb and Zn. When the results were expressed as concentration (mg·l⁻¹) no significant differences were found. However, considering the dry matter, results showed a clear difference between the mass fractions (mg·kg⁻¹ d.w.) of skim milk and whole milk for the elements Br, Ca, K, Na, Rb and Zn, indicating that the removal of fat caused a concentration effect in the dry matter of skim milks. Discrepancies were found between the concentrations of Ca and Na measured by INAA and the values informed in the labels. Ca showed variations within 30% for most samples, while concentrations of Na were up to 190% higher than informed values. The sample preparation and the INAA procedure were appropriate for the determination of Br, Ca, Co, Cs, Fe, K, Na, Rb and Zn in milk samples.     

Comparison of neutron activation analysis with conventional detection techniques for the evaluation of trace elemental contamination in Mallard (<Emphasis Type="Italic">Anas platyrhynchos</Emphasis>) feathers

Instrumental neutron activation analysis (INAA) was used to determine trace elemental contamination in bird feathers. Primary feathers from twelve mallard (Anas platyrhynchos) ducks, migrating through the Thousand Islands region of Ontario, Canada, were analyzed for selenium, mercury, chromium, arsenic and antimony. Certified reference materials were used to assess the quality of the analytical procedure. Quantification of chemical elements was performed using Ortec Gamma Vision software. Five chemical elements were quantified, with corresponding analytical uncertainties of less than 20%. Results indicated the presence of As (max = 0.13 mg kg⁻¹), Cr (max = 2.6 mg kg⁻¹), Hg (max = 7.7 mg kg⁻¹), Sb (max = 0.31 mg kg⁻¹) and Se (max = 1.31 mg kg⁻¹). To assess the validity of using INAA as a quantitative analytical technique for feather samples, two standard reference materials were examined and mercury results were compared to those obtained from both direct mercury analysis (DMA) and cold vapour atomic absorption spectroscopy (CVAAS). Several CVAAS results differed significantly from the INAA results; in many instances CVAAS appeared to under-report when compared to INAA, with relative percent difference values as high as 126%. Conversely, results obtained using DMA compared favourably with INAA. For all samples, RPD values were within 30%. This is the first study to use INAA to examine feather contamination in Canadian migratory waterfowl and the first to corroborate INAA feather results by comparing them to those obtained using CVAAS and DMA.     

Preparation and characterization of loess sediment for use as a reference material in the annual radiation dose determination for luminescence dating

Loess sediment was prepared and characterized with well-established K, Th and U contents, and corresponding ⁴⁰K, ²³²Th and ^235,238U activities, intended for use as a reference material in the annual radiation dose determination for luminescence dating. To this purpose, loess was collected in Volkegem, Belgium, and — after drying, pulverizing and homogenizing — characterized via k ₀-INAA and HPGe gamma-ray spectrometry. This led to 12 kg material with a grain size below 50 μm, with established K, Th and U homogeneity, with the ²³²Th and ²³⁸U decay series proven to be in equilibrium, and with the following K, Th and U reference data: K = 16.5±1.5 g·kg⁻¹ (⁴⁰K = 497±45 Bq·kg⁻¹); Th = 10.4±0.6 mg·kg⁻¹ (²³²Th = 42.2±2.5 Bq·kg⁻¹); U = 2.79±0.12 mg·kg⁻¹ (²³⁸U = 34.5±1.5 Bq·kg⁻¹; ²³⁵U = 1.59±0.09 Bq·kg⁻¹; ^235+238U = 36.1±1.7 Bq·kg⁻¹). These data were confirmed via comparison with the results from NaI(Tl) field gamma-ray spectrometry, thick-source ZnS alpha-counting and thick-source GM beta-counting (after converting all data to Gy·ka⁻¹). The reference material is available (as aliquots up to 200 g) from the Ghent Luminescence Laboratory to all interested luminescence dating laboratories upon motivated request.     

Determination of trace elements in high purity copper by INAA, GFAAS and ICP/AES

Trace impurity elements in high purity copper metal (4 mine class) put on the market were analyzed by Instrumental Neutron Activation Analysis (INAA) and the results compared with those from Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS) and Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES). The sample irradiation was done at the irradiation facilities (thermal neutron flux, 5·10¹² n·cm⁻²·s⁻¹) of the TRIGA Mark-III research reactor in the Korea Atomic Energy Research Institute. Four unalloyed copper standards (NIST SRM # 393, 394, 395 and 398) were used to identify the accuracy and precision of the analytical procedure. The homogeneity of samples was assessed by means of the elements such as Ag, As, Co, Sb, Se and Zn. The analytical results of INAA, GFAAS and ICP-AES were in good agreement within expected uncertainties each other and showed the possibility of using them for the analytical quality control.     

Application of radiochemical methods and dispersion model in the study of environmental pollution in Brazil

Methodologies for analysis of anthropogenic and natural radionuclides in marine samples were developed and applied in environmental samples. Results of systematic measurements of these radionuclides have showed that artificial radioactivity levels are in agreement with the values from the regions not affected directly by nuclear accidents or nuclear reprocessing plant discharges and are due to the global fallout. The average concentration of¹³⁷Cs is of 1.4 Bq·m⁻³ in seawater, ranges from 13 to 220 mBq·kg⁻¹ in fish, and from 0.4 to 1.8 Bq·kg⁻¹ for sediments.⁹⁰Sr levels in seawater are of 1.8 Bq·m⁻³ and in fish vary from 19 to 75 mBq·kg⁻¹. Sediments present concentrations of⁹⁰Sr lower than 0.8 Bq·kg⁻¹ and for^239+240Pu of 0.03 to 0.18 Bq·kg⁻¹.²¹⁰Po levels in fish range from 0.5 to 5.3 Bq·kg⁻¹. The data generated represent reference values for our country and are used to estimate the intake levels of these radionuclides by consuming of marine products.     

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.     

Determination of phosphorus in polymers by INAA

An INAA technique employing beta spectrometry was developed for the determination of phosphorus in polymers. The (n,γ) reaction on phosphorus produces³²P, half-life 14.3 days, a pure beta emitter with end-point energy 1.71 MeV. Polymer samples in the form of powders, films and pellets are irradiated and then counted with a plastic scintillator. The beta spectrum is corrected for interferences (especially Sb, Zn and Br which are quantified by gamma spectrometry) and for energy loss in the thick sample. Samples must also be analyzed for S and Cl which cause nuclear interferences. With an irradiation time of 4 hours at a neutron flux of 5·10¹¹ n·cm^{−2 s −1}, decay time 10 days and counting time 10 minutes, the sensitivity is 520 counts/μg phosphorus and the detection limit is typically 2μg/g.     

Instrumental neutron activation analysis of gunpowder residues

A procedure has been developed for the detection of gunpowder residues deposited on the hand of a person firing a gun. The method is based on neutron activation analysis of the antimony level on the surface of the hand. The surface materials are removed by a film made by spraying a 4% solution of cellulose acetate in acetone, which sets to form a thin film that can readily be stripped off. This technique was found to be preferable to the paraffin-lift technique which is in common use. Following neutron activation of the film in a nuclear reactor, antimony is assayed by high-resolution Ge(Li) spectrometry without prior chemical processing. The sensitivity of the method is about 5·10⁻⁹ g Sb, with a precision of about ±10% at a neutron flux of 5·10¹³ n·cm⁻²·sec⁻¹. Analysis of twenty samples taken from the hands of persons who had fired a pistol gave Sb levels of 0.4±0.2 μg, compared with 0.024±0.013 μg found on the hands of persons who had not fired a revolver. The possible extension of the present technique to include the determination of additional elements is discussed. Project carried out with the support of the Office of the Chief Scientist to the Ministry of Defense and with the collaboration of the Israel Police.     

Concentration of chlorine in rice plant components

Rice plants were grown in an experimental field and separated at harvest into different components, including polished rice, rice bran, hull, straw and root. The distribution of chlorine in these components was determined by instrumental neutron activation analysis. The concentration of chlorine in the roots was the highest (4800 mg·kg⁻¹ dry wt.) and that in the polished rice was the lowest (140 mg·kg⁻¹ dry wt.) among the plant components. The content of chlorine in the polished rice was about 2% of the entire plant, and the rest was present in the inedible portions; about 75% of the total chlorine content was in the straw. The percentage of chlorine removed from the surface soil layer to the above ground biomass of the rice plants was calculated as 5% every year. The chlorine concentrations in leaf blades of different positions collected from four growing stages varied by more than one order of magnitude, and were well correlated with the sum concentrations of major cations (potassium + calcium + magnesium). This may be attributed to the fact that the translocation rate of chlorine among the leaf blades with age depends on the concentrations of the major cations.     

Determination of metals in alloys by neutron capture gamma-ray spectrometry

A collimated neutron beam capable of providing a thermal neutron flux of 4.75·10⁷ n·cm⁻²·sec⁻¹ has been used to analyze alloy samples of 1–5 g during relatively short irradiation times of 30 min by the use of neutron capture gamma-ray spectrometry. The analyses were performed by using a mathematical treatment that relates the count ratio of every constituent present in the matrix with the concentration and thus it requires no standards. The technique was applied to the analysis of steel and gold alloy samples. Errors ranged from 0.8%–10%.     

Rare-earth elemental analysis of banded iron-formations by instrumental neutron activation analysis

Representative banded iron-formations (BIFs) from various locations of the eastern Indian geological belt were investigated by instrumental neutron activation analysis (INAA). After pre-concentration, irradiation was carried out using a neutron flux of 5.1·10¹⁶ m⁻²·s⁻¹, 1.0·10¹⁵ m⁻²·s⁻¹ and 3.7·10¹⁵ m⁻²s⁻¹, with thermal, epi-thermal and fast neutrons, respectively. The activities in these samples were measured by a HPGe detector. Ten rare-earth elements, such as La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu, have been qualitatively identified and quantitatively estimated in these samples. The present investigation is an example of employing a pre-concentration method for high iron-containing ores prior to neutron activation analysis.     

Radioactivity of coals and fly ashes

The level and the behavior of the naturally occurring primordial radionuclides ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²³²Th, ²²⁸Ra and ⁴⁰K in coals and fly ashes are described. The activity concentrations of the examined coals and originated from coal mines in Greece ranged from 117 to 435 Bq·kg⁻¹ for ²³⁸U, from 44 to 255 Bq·kg⁻¹ for ²²⁶Ra, from 59 to 205 Bq·kg⁻¹ for ²¹⁰Pb, from 9 to 41 Bq·kg⁻¹ for ²²⁸Ra and from 59 to 227 Bq·kg⁻¹ for ⁴⁰K. These levels are comparable to those appeared in coals of different countries worldwide. The activity concentrations of the examined fly ashes and produced in coal-fired power plants in Greece ranged from 263 to 950 Bq·kg⁻¹ for ²³⁸U, from 142 to 605 Bq·kg⁻¹ for ²²⁶Ra, from 133 to 428 Bq·kg⁻¹ for ²¹⁰Pb, from 27 to 68 Bq·kg⁻¹ for ²²⁸Ra and from 204 to 382 Bq·kg⁻¹ for ⁴⁰K. The results showed that there is an enrichment of the radionuclides in fly ash relative to the input coal during the combustion process. The enrichment factors (EF) ranged from 0.60 to 0.76 for ²³⁸U, from 0.69 to 1.07 for ²²⁶Ra, from 0.57 to 0.75 for ²¹⁰Pb, from 0.86 to 1.11 for ²²⁸Ra and from 0.95 to 1.10 for ⁴⁰K.     

Contents of238Pu,239,240Pu and137Cs in sediments and shore depositions of the Vltava river in 1995–1996

The²³⁸Pu,^239,240Pu and¹³⁷Cs concentrations in sediments and shore deposition samples of the Vltava river were determined.^239,240Pu and¹³⁷Cs concentrations in sediment samples (five locations) ranged from 19.6 to 124.8 mBq·kg⁻¹ and from 1.8 to 28.2 Bq·kg⁻¹, respectively. The²³⁸Pu,^239,240Pu and¹³⁷Cs concentrations in shore deposition samples (four locations) ranged from 2 to 16.8, from 26.8 to 477.2 mBq·kg⁻¹, and from 1.6 to 86.3 Bq·kg⁻¹, respectively. The superficial activity of studied radionuclides in shore deposition areas was determined and radionuclide origin at studied locations was discussed.