Instrumental Epithermal Neutron Activation Analysis Research Articles

The features of heavy metals and metalloids accumulation in the phytomass of the amphipodous moss <i>Pleurozium schreberi</i> (Brid.) Mitt. in the conditions of the Krasnosamarsky Forest area (Samara Region) and the National Park «Buzuluksky Bor» (Orenburg Region)

The paper analyzes ecological and geochemical features of the moss Pleurozium schreberi (Brid.) Mitt., growing in artificial pine plantings of the National Park Buzuluksky Bor (Orenburg Region) and the Krasnosamarsky Forest (Samara Region). The research has been carried out within the framework of the International Program ICP Vegetation (https://icpvegetation.ceh.ac.uk), on the practical use of some bryophyte species in the environmental monitoring of multi-element air pollution in the countries of Western and Eastern Europe and a number of other countries. In the National Park Buzuluksky Bor and the Krasnosamarsky Forest, where species diversity and ecological characteristics of bryophytes have been studied for several years, the phytomass of the moss Pleurozium schreberi has been selected. This species is included in the species list proposed by the organizers of the research work under the UNECE ICP Vegetation Program. A multi-element analysis of Pleurozium schreberi phytomass has been carried out on the basis of the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research in Dubna using instrumental epithermal neutron activation analysis (ENAA). The biogeochemical similarity of the moss Pleurozium schreberi from the Krasnosamarsky Forest and Buzuluksky Bor, estimated by the concentration coefficients, has manifested itself in relation to a large group of heavy metals and metalloids, characterized by a relatively low ability to accumulate in its phytomass (Ti, V, Cr, Fe, Co, As, Se, Rb, Sr, Mo, Cd). Some differences have been revealed in relation to the elements with the maximum accumulation: Cu and Zn in the Krasnosamarsky Forest area, Mn and Ni - in the Buzuluksky Bor. A relatively low content of most of the analyzed heavy metals and metalloids in the soil of the studied territories as well as in the phytomass of the biomonitor moss Pleurozium schreberi allows us to consider them to be background for the steppe zone of the European part of the Russian Federation.

Major and Trace Element Content of Tribulus terrestris L. Wildlife Plants.

The genus Tribulus L. (Zygophyllaceae) includes 12 species, the most important of which is Tribulus terrestris L. This annual herb grows in temperate and tropical climates, and has a rich chemical composition of biologically active substances and chemical elements. Medicinal plants, and the phytopreparations obtained from them, are becoming more and more popular in world practice as they are used to successfully treat human diseases. Their therapeutic effect is due to the presence in them, of a variety of natural compounds and biologically important trace elements, especially in higher concentrations present in higher doses. T. terrestris is becoming more and more popular for the treatment of diseases of the human genital area and sexual dysfunctions. The elemental content in the tissues of leaf, flower, and fruit of T. terrestris was determined by using multi-element instrumental epithermal neutron activation analysis. For the first time, 26 essential and trace elements were observed in the plant species collected in Russia (from cultivated) and China (wild growing). It was confirmed that the elemental composition of T. terrestris grass varies depending on the habitat (geographic zones). The place of growth affects the accumulation of elements by the plant.

MACRO- AND MICROELEMENTS DISTRIBUTION IN URBANIZED ECOSYSTEMS OF KARELIA

The aim was to study the distribution of macro-and microelements in the main urban ecosystems of Karelia. Methods. Samples of soil, vegetation, surface water, sediments and biota (fish) were taken. In total, 300 samples were collected. The analysis of the material was carried out using epithermal instrumental neutron activation analysis (INAA), x-ray spectral analysis (XRF), and atomic absorption spectrometry (AAS) with "cold steam" and inductively coupled plasma spectrometry (ICP-MS). Concentration of 32 chemical elements in soil, birch leaves, sediments, water and biota (fish) was determined. Results. The distribution of macro- and microelements in soil and vegetation of these main cities of Karelia was determined. Geochemical profiles of distribution of elements in soils and vegetation were constructed. Concentration of heavy and toxic metals in the samples of water and sediments was close to the background values. High concentration of mercury in the muscles of predatory fish was found (CHg = 0.2÷0.3 mcg/kg). Conclusions. The levels of total accumulation of heavy and toxic metals in the soil of Petrozavodsk are classified as hazardous (Zc = 56), and soil pollution in Pitkyaranta, Sortavala and Suoyarvi is considered moderately dangerous (Zc = 15-31). A high degree of correlation between the concentration of elements in the soil and birch leaves was found. The water in lake Ladoga, lake Onega, and lake Suoyarvi in terms of the concentration of the elements presented in the article meets the Russian standards for drinking water.

Iodine analysis of foodstuffs samples using epithermal instrumental neutron activation analysis

Iodine is an essential element that has an important role in the proper growth and thyroid hormone functioning of humans. Iodine deficiency was correlated with the health status of human-caused by malnutrition. The analytical method to analyze the Iodine content on foodstuffs is limited because Iodine concentration exists in a level of a trace. 127I has a ratio of I 0 to s relatively high, and it is possible to obtain 128I (t1/2 = 24.5 minutes) using nuclear reaction with an epithermal neutron. Samples were collected at Magelang region, and it consists of foodstuffs that consumed by the citizen. All sample has been dried using Freeze dryer at-90 °C and 0.03 bar for 24-48 hours. After drying, the sample then pounded to get the form of granules smooth, about 100-150 mesh. About 40 to 130 mg of sample was weighed accurately on a clean micro vial of Polyethylene. Irradiation has been carried out at l5 MW reactor power using neutron epithermal for 45 seconds at the rabbit facility of GA. Siwabessy reactor. After cooling 5 to 10 minutes, the irradiated sample then counted for 300 seconds, and the gamma-ray spectra obtained emitted have been analyzed by Hyperlab software. Several standard reference materials of NIST have been used as analytical quality control. The experimental result shows that the Iodine has the Boron ratio, RB, and the Advantage factor, Fadv, equal to 2.4 and 21, respectively. Trace element of Iodine has been determined quantitatively on nine spices, seven types of meat, and 32 vegetables. The Iodine concentration on spices have average 1.57 ± 0.23 mg/kg with range value 0.38 mg/kg to 3.4 mg/kg. Iodine on vegetable have average of 2.00 ± 0.43 mg/kg with range value of 0.38 mg/kg to 7.30 mg/kg. Meanwhile, its concentration on meat has range 0.71 mg/kg to 2.16 mg/kg, with an average of 1.44 ± 0.28 mg/kg, lower than that on vegetables. Epithermal INAA is a reliable analytical technique for Iodine determination quantitatively.

Moss and Lichen Biomonitoring of Atmospheric Pollution in the Western Cape Province (South Africa)

For the first time, the atmospheric deposition of trace elements was investigated in two regions (Cape Winelands and Cape Peninsula) of the Western Cape Province of the Republic of South Africa (RSA) using naturally growing mosses and lichens. A total of 33 elements were determined by epithermal instrumental neutron activation analysis (INAA). Multivariate statistical analysis was used to identify and characterize different pollution sources.

Air Pollution Study in the Republic of Moldova Using Moss Biomonitoring Technique.

Moss biomonitoring using the species Hypnum cupressiforme (Hedw.) and Pleurocarpous sp was applied to study air pollution in the Republic of Moldova. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Cd, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Hf, Ta, W, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Geographical distribution maps were prepared to point out the regions most affected by air pollution and relate this to potential sources of contamination. Median values of the elements studied were compared with data from the European moss biomonitoring program. The cities of Chisinau and Balti were determined to experience particular environmental stress.

Multi-element atmospheric deposition in Macedonia studied by the moss biomonitoring technique.

Moss biomonitoring technique using moss species Homolothecium lutescens (Hedw.) Robins and Hypnum cupressiforme (Hedw.) was applied to air pollution studies in the Republic of Macedonia. The study was performed in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP). The presence of 47 elements was determined by instrumental epithermal neutron activation analysis, atomic absorption spectrometry and atomic emission spectrometry with inductively coupled plasma. Normality of the datasets of elements was investigated, and Box-Cox transformation was used in order to achieve normal distributions of the data. Different pollution sources were identified and characterized using principal component analysis (PCA). Distribution maps were prepared to point out the regions most affected by pollution and to relate this to the known sources of contamination. The cities of Veles, Skopje, Tetovo, Radoviš and Kavadarci were determined to experience particular environmental stress. Moreover, three reactivated lead-zinc mines were also shown to contribute to a high content of lead and zinc in the eastern part of the country. However, a comparison with the previous moss survey conducted in 2005 showed a decreasing trend of pollution elements that are usually associated with emission from industrial activities.

Assessment of contamination with trace elements and man-made radionuclides around Temelin Nuclear Power Plant in Czech Republic

Abstract The results of atmospheric deposition of heavy metals and trace elements, determined in moss Pleurozium schreberi collected around the Temelin Nuclear Power Station in the Czech Republic in 2011, are presented. The monitored area around NPP Temelin comprises 29 sampling sites located along 8 profile radii stretched as of 2, 5, 10, and 20 km from the NPP. Some pollution sources are located in the study area. A total of 42 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Ta, W, Au, Hg, Pb, Th, and U) were determined by epithermal instrumental neutron activation analysis with the neutron flux density Φ epi=3.6×10 11 n/(cm 2 s) at the pulsed fast reactor IBR-2, FLNP, JINR. To determine the presence of radionuclides and their measurable activity in samples, laboratory gamma spectrometry was found to be the best detection method. A coaxial HPGe detector with samples in the geometry of Marinelli containers in the laboratory of Faculty of Nuclear Sciences CTU in Prague was used. To assess the influence of NPP Temelin on the Biomass in 20 km radius, the mass activity of 137 Cs (Bq/kg) was determined. No other short-term radionuclides have ever been identified in any spectrum.

Characterization and quantification of engineered nanoparticles in food by epithermal instrumental neutron activation analysis and electron microscopy

Engineered nanoparticles (NPs) have increasingly been used in various areas including agriculture and food packaging, which may potentially cause contamination in food products. In this study, a combination of analytical techniques was used to detect, characterize, and quantify engineered NPs (cerium (IV) oxide (CeO2), silica (SiO2) NPs, and their mixture) in food matrices. A series of concentrations of CeO2, SiO2, and their mixtures from 0 to 0.75 wt% were mixed in soybean powders. The presence of engineered NPs was investigated using transmission electron microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy. The average size of CeO2 and SiO2 was 28.5 and 30.5 nm in diameter, respectively. CeO2 NPs were irregular octahedral and cubic in shape, while SiO2 NPs were spherical. The concentration of NPs in soybean powders was analyzed by epithermal instrumental neutron activation analysis (EINAA). Calibration curves were plotted for quantification of NPs in soybean powders (R 2 = 0.996 and 0.994 for CeO2, SiO2 NPs in soybean powders, respectively; R 2 = 0.995 and 0.997 for CeO2 and SiO2 NP in a mixture in soybean powders, respectively). The study of the detection limit (DL) demonstrates that at 99 % confidence interval, EINAA can detect both NPs at 0.1 wt% in soybean powders. Satisfactory recoveries were obtained for samples with a concentration at and higher than the DL (86.2–104.7 % for CeO2 NPs and 85.7–95.2 % for SiO2 NPs; 87.5–101.3 and 85.6–93.5 % for CeO2 and SiO2 NPs in a mixture in soybean powders, respectively).

Atmospheric Deposition Study in the Area of Kardzhali Lead-Zinc Plant Based on Moss Analysis

For the first time the moss biomonitoring technique was used to assess the environmental situation in the area affected by a lead zinc plant as one of the most hazardous enterprises in Bulgaria. 77 Hypnum cupressiforme moss samples were collected in the Kardzhali municipality, in the summer and autumn of 2011. The concentrations of a total of 47 elements were determined by means of instrumental epithermal neutron activation analysis (ENAA), atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Multivariate statistics was applied to characterize the sources of elements detected in the samples. Four groups of elements were found. In comparison to the data averaged for the area outside of the town, the atmospheric deposition loads for the elements of industrial origin in Kardzhali, where the smelter chimney is located, were found to be much higher. Median levels of the measured concentrations for the most toxic metals (Pb, Zn, Cd, As, Cu, In, Sb) were extremely high in this hot spot when compared to the median Bulgarian cross-country data from the 2010/2011 European moss survey. GIS technology was used to produce element distribution maps illustrating deposition patterns of element pollutants in the study area. The results obtained contribute to the Bulgarian environmental research used to study and control the manufacturing processes of a lead-zinc smelter in the town of Kardzhali.

Determination of trace concentrations of thorium in uranium oxide matrix by epithermal instrumental neutron activation analysis

An epithermal instrumental neutron activation analysis (EINAA) method using cadmium filter was standardized to determine trace concentrations of thorium in four samples of uranium oxide (U3O8) samples. Samples and thorium standards, wrapped with cadmium foil, were irradiated at a reactor neutron flux of about 1012 cm−2 s−1. Radioactive assay was carried out using a Compton suppressed anticoincidence gamma ray spectrometer consisting of HPGe-BGO detectors coupled to MCA. Concentrations of thorium in these samples were found to be in the range of 15–72 mg kg−1. EINAA results were validated by determining thorium concentrations in uranium matrix by standard addition method. EINAA results were compared with those obtained by two wet chemical methods namely ion chromatography (IC) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results obtained by the three methods were found to be in good agreement, indicating further validity of the proposed EINAA method.

Trends of atmospheric deposition of trace elements in Macedonia studied by the moss biomonitoring technique

In 2002 and 2005 the moss biomonitoring technique was applied to air pollution studies in the Republic of Macedonia in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE-ICP Vegetation) Convention on Long-Range Transboundary Air Pollution (LRTAP). In August 2005 samples of the terrestrial mosses Homolothecium lutescens and Hypnum cupressiforme were collected at 72 sites evenly distributed over the territory of the country, in accordance with the sampling strategy of the European moss survey programme. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy Hf, Ta, W, Hg, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Distributional maps were prepared to point out the regions most affected by pollution and to relate this to known sources of contamination. A few areas, as in 2002, are experiencing particular environmental stress: Veles, Skopje, Tetovo, Radoviš and Kavadarci-Negotino, whereas the agricultural regions in the south, south-west, and south-east show median European values for most elements of mainly pollution origin. A significant increase in the content of Ni is noticed in the 2005 moss survey compared with 2002, due to the increased production of the ferro-nickel smelter in Kavadarci. A higher content of Cd, Hg, and Pb in 2005 relative to 2002 can be explained by pollution from the lead-zinc smelter in Veles, as well as the pollution that comes from the open slag waste dump of this smelter. Protection activities on the dump of slag from the former ferrochromium smelter located near Tetovo resulted in a lower content of Cr in the 2005 moss survey.

Epithermal instrumental neutron activation analysis in conjunction with anti-coincidence gamma-ray spectrometry for investigating iodine levels in Canadian foods

In order to reduce interferences from high activities of 24Na, 56Mn, 82Br, and 38Cl as well as to improve detection limits, precision, and accuracy of measuring iodine levels in biological materials, foods and diets in particular, an epithermal instrumental neutron activation analysis (EINAA) method in conjunction with anti-coincidence (EINAA-AC) gamma-ray spectrometry was employed. The Compton scattering background in the region of the 442.9-keV photopeak of 128I was significantly suppressed by anti-coincidence counting. In order to validate the EINAA-AC method as well as to evaluate its broad applicability to diverse types of biological material, 17 NIST and IAEA reference materials containing very low to high levels of iodine as well as interfering elements were analyzed by the EINAA-AC method. The samples were irradiated in the cadmium-lined pneumatic site at a neutron flux of 2 × 1011 cm−2 s−1 of the Dalhousie University SLOWPOKE-2 Reactor (DUSR) facility for 10 or 20 min followed by 1-min decay and 30-min counting. The detection limit for iodine by EINAA-AC was improved by a factor of 2–5 compared to EINAA depending on the sample matrix and other factors, and a limit of 3–5 μg kg−1 was achieved for low-salt foods. We found the RSD to be about ±5 % above 200, increasing to ±10 % at 20, and then to greater than ±30 % at about 5 μg kg−1 iodine levels.

Estimation of total as well as bioaccessible levels and average daily dietary intake of iodine from Japanese edible seaweeds by epithermal neutron activation analysis

An epi-thermal instrumental neutron activation analysis (EINAA) method in conjunction with Compton suppression spectrometry (EINAA-CSS) was used for the determination of total iodine in eight different species of edible seaweeds from Japan. This method gave an absolute detection limit of about 2 μg. The accuracy of the method was evaluated using various reference materials and found to be generally in agreement within ±6% of the certified values. The longitudinal distributions of iodine at different growing stages in Japanese sea mustard and tangle seaweeds were investigated. For a 150-cm-high tangle, the highest concentration (5,360 mg/kg) of iodine was found at the root, then decreased slowly to 780 mg/kg in the middle portion (60–75 cm), and increased to 2,300 mg/kg at the apex. On the other hand, for a 190-cm-high sea mustard the highest levels of iodine were found both at the roots (164 mg/kg) and apex (152 mg/kg) with lower values (98 mg/kg) in the middle section. In order to estimate the bioaccessible fraction of iodine, seaweeds were digested by an in vitro enzymolysis method, dietary fibre separated from residue, and both fractions analyzed by EINAA-CSS. The average daily dietary intakes of total (0.14 mg) as well as bioaccessible fraction (0.12 mg) of iodine from the consumption of sea mustards were estimated.

A new method for the analysis of titanium, barium, and arsenic in obsidian via epithermal neutron activation analysis

A new instrumental epithermal neutron activation analysis procedure to quantitatively determine titanium, barium, and bromine in obsidian with improved sensitivity has been developed. The advantage of epithermal activation for Ti, Ba, and Br is demonstrated with multiple geological standards and the ability to determine arsenic in obsidian is demonstrated. The results for titanium are compared to previous electron-microprobe results for Kenyan obsidian.

Determination of iodine in biological materials by pseudo-cyclic epithermal INAA using anti-coincidence gamma-ray spectrometry and estimation of expanded uncertainties

Epithermal instrumental neutron activation analysis (EINAA) technique in conjunction with anti-coincidence gamma-ray spectrometry (AC) has been applied for the determination of ppm to ppb levels of iodine in biological materials containing high levels of Al, Br, Cl, K, Mn, and Na. Both conventional EINAA-AC and pseudo-cyclic EINAA-AC (PC-EINAA-AC) methods using a combination of Cd and B filters have been developed using Dalhousie University SLOWPOKE-2 reactor (DUSR) facility. The expanded uncertainties (EU), at about 95% confidence level, for iodine in biological materials by EINAA-AC varied between 6 and 10%. The advantages of the non-destructive PC-EINAA-AC method has been successfully demonstrated by analyzing the NIST Pine Needles (SRM 1575) containing a low amount of iodine in presence of high quantities of Mn and other interfering elements where an iodine content of 92.8 μg kg−1 with an EU of 6.1 μg kg−1 and a detection limit of 40 μg kg−1 has been obtained at the end of fourth cycle.

Molecular iodine selective membrane for iodate determination in salt samples: chemical amplification and preconcentration

A molecular iodine selective membrane has been used for preconcentration of I(2) generated in situ by iodometric reaction of IO(3)(-) with excess I(-) in acidic medium (pH 1-2). This iodometric reaction amplifies the iodine content six times resulting in enhancement of analytical response ranging from three times for molecular methods to six times for elemental methods. The chemical conditions of this iodometric reaction were optimized for quantitative generation and subsequent sorption of I(2) in the membrane samples (96 +/- 3%). The homogeneous transparent membrane was prepared by immobilizing I(2)-complexing polyvinylpyrrolidone (PVP) in the plasticized cellulose triacetate matrix. Four different analytical methods were examined for quantitative determination of IO(3)(-) in iodized salt samples by preconcentrating it as I(2) in the membrane matrix. These methods were: (1) spectrophotometry of the PVP-I(2) complex formed in the membrane matrix, (2) a radiotracer method using I(-) tagged with (131)I radiotracer, (3) instrumental neutron activation analysis (INAA), and (4) energy-dispersive X-ray fluorescence (EDXRF) analysis. The IO(3)(-) contents thus determined in the iodized salt samples by the membrane-based radiotracer method were compared with the total iodine determined in salt samples by epithermal instrumental neutron activation analysis (EINAA). The membrane-based method for iodate determination in salt samples has advantages over conventional analytical methods, for example preconcentration and chemical amplification, and is free from interference from anions.

Determination of Iodine in Libyan Food Samples Using Epithermal Instrumental Neutron Activation Analysis

Epithermal instrumental neutron activation analysis (EINAA) has been used to determine the iodine content of many individual food materials that constitute the typical Libyan diet. The selected samples include different varieties of local and imported foods such as wheat and barley products, rice, bread, legumes such as chick peas and lentil, table salt, and commonly used spices, including thyme and fenugreek. Both conventional and anticoincidence gamma-ray spectrometry techniques have been employed. Epithermal INAA in conjunction with anticoincidence counting has been found to provide the most reliable results. For quality control purposes, a number of NIST biological reference materials were analyzed. The range of daily dietary intake has been calculated as 100-180 microg of iodine per day, which is within the recommended range. Bread was identified as a significant source of iodine in the Libyan diet, as it contributed 99 microg/d.

Simultaneous determination of tantalum, niobium, thorium and uranium in placer columbite-tantalite deposits from the Akim Oda District of Ghana by epithermal instrumental neutron activation analysis

Tantalum, niobium, thorium and uranium contents of 21 columbite-tantalite minerals from the Akim Oda District of Ghana have been determined using epithermal instrumental neutron activation analysis (ENAA) with a conventional counting system. As thermal neutron filters, boron carbide was encapsulated in the irradiation vials during irradiation. The samples were irradiated at one of the outer irradiation channels in the Ghana Research Reactor-1 facility, and counted directly. Various elements were identified and quantified using 172 keV of 182mTa, 871 keV of 94mNb, 86.5 keV of 233 Th and 74.7 keV of 239U. The precision and accuracy of the method were evaluated using standard reference materials and the precision was found to be within 5% with comparable accuracy. The composition of columbite-tantalite minerals ranged from 33.1% to 59.2% Ta2O5 and 19.2% to 44.6% Nb2O5, ThO2 and U3O8 the levels were 0.024-0.045% and 0.014-0.048%, respectively.

ENAA studies of chromium uptake by Arthrobacter oxydans

To study chromium uptake by Arthrobacter oxydans [Cr(VI)-reducing bacteria isolated from Columbia basalt rocks, USA] the instrumental epithermal neutron activation analysis (ENAA) was applied. It was established that chromate accumulation is dose-dependent and it is most intensive in the interval of Cr(VI) concentrations (10-50 mg/l). At lower concentrations of Cr(VI) (up to 50 mg/l) the most intensive formation of Cr(V) was found using ESR method. Besides, it was established that reduction from Cr(VI) to Cr(V) is a faster process than the uptake of Cr(VI). According to ENAA measurements, in contrast to Cr(VI), Cr(III) is not accumulated in Arthrobacter oxydanscells up to concentrations of 200 mg/l. Using epithermal neutron activation analysis the background levels of 17 major, minor and trace elements were determined in Arthrobacter oxydans.