Possibilities of ED-XRF with radionuclide sources for analysis of plants

A comparative evaluation of the applicability of different radionuclide sources for the determination of toxic elements in plants by ED-XRF is presented.²³⁸Pu or¹⁰⁹Cd are suggested as most suitable single excitation sources in ED-XRF for monitoring investigations. More elements are determined with a combination of⁵⁵F/¹⁰⁹Cd(²³⁸Pu)/²⁴¹Am. The results obtained by radionuclide ED-XRF analysis of different plants show that the method permits the reliable determination of Br, Ca, Fe, K, Mn, Rb, Sr and Zn in plant bioindicators. For toxic elements like As, Cd, Cu Cr, Hg, Ni, Se and Pb the detection limits of the method are not low enough.     

Distribution of aquatic plants and absorption of radionuclides by plants through the leaf surface in brackish Lake Obuchi, Japan, bordered by nuclear fuel cycle facilities

We investigated the distribution of aquatic plants and the absorption of radionuclides by them in the brackish Lake Obuchi, Japan, which is bordered by nuclear fuel cycle facilities. We studied 5 species of submerged plants: Zannichellia palustris, Ruppia maritima, Potamogeton pectinatus, Zostera japonica, and Z. marina. The plants contained many elements, including radionuclides. The concentrations of ²³⁸U, ¹³⁷Cs, and ⁹⁰Sr in Z. marina were 11.3-12.4, 0.000-0.144, and 0.151-0.202 Bq^.kg^-1 dw, respectively. Those in Z. japonica were 5.2-8.8, 0.000-0.267, and 0.081-0.175 Bq^.kg^-1 dw, respectively. The concentrations of these radionuclides in the plants tended to be higher in higher-salinity regions than in lower-salinity regions of the lake. We found a close relationship between photosynthetic activity and the absorption of stable Sr by plants in the laboratory. Salinity, illumination, and water temperature influenced the photosynthetic activity of the plants and the consequent absorption of elements.     

Arsenic compounds in terrestrial organisms. IV. Green plants and lichens from an old arsenic smelter site in Austria

Two lichens and 12 green plants growing at a former arsenic roasting facility in Austria were analyzed for total arsenic by ICP–MS, and for 12 arsenic compounds (arsenous acid, arsenic acid, dimethylarsinic acid, methylarsonic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, the tetramethylarsonium cation and four arsenoriboses) by HPLC–ICP–MS. Total arsenic concentrations were in the range of 0.27 mg As (kg dry mass)⁻¹ (Vaccinium vitis idaea) to 8.45 mg As (kg dry mass)⁻¹ (Equisetum pratense). Arsenic compounds were extracted with two different extractants [water or methanol/water (9:1)]. Extraction yields achieved with water [7% (Alectoria ochroleuca) to 71% (Equisetum pratense)] were higher than those with methanol/water (9:1) [4% (Alectoria ochroleuca) to 22% (Deschampsia cespitosa)]. The differences were caused mainly by better extraction of inorganic arsenic (green plants) and an arsenoribose (lichens) by water. Inorganic arsenic was detected in all extracts. Dimethylarsinic acid was identified in nine green plants. One of the lichens (Alectoria ochroleuca) contained traces of methylarsonic acid, and this compound was also detected in nine of the green plants. Arsenobetaine was a major arsenic compound in extracts of the lichens, but except for traces in the grass Deschampsia cespitosa, it was not detected in the green plants. In contrast to arsenobetaine, trimethylarsine oxide was found in all samples. The tetramethylarsonium cation was identified in the lichen Alectoria ochroleuca and in four green plants. With the exception of the needles of the tree Larix decidua the arsenoribose (2′R)‐dimethyl[1‐O‐(2′,3′‐dihydroxypropyl)‐5‐deoxy‐β‐D ‐ribofuranos‐5‐yl]arsine oxide was identified at the low μg kg⁻¹ level or as a trace in all plants investigated. In the lichens an unknown arsenic compound, which did not match any of the standard compounds available, was also detected. Arsenocholine and three of the arsenoriboses were not detected in the samples. Copyright © 2000 John Wiley & Sons, Ltd.     

Behavior of Zn,Cu, Pb and Cd in biota of Yangtze Estuary

The contents of zinc, copper, lead and cadmium were measured in the dominant species (plants:Scripus triquetor andPhrgrmites australis, macrobenthos:Ilyoplax deschampsin, Helice tridens tientsinensis, Bullacta exarata and Corbicula fluminea, and migrating waders: Calidris ruficollis and C. alpina) of the ecosystem of Yangtze Estuary, China, from 1995–1998. Results show that:

1. (1)

   Since the heavy metals stored in plants during growth seasons will be released into the environment in winter, plants are temporary stocks for metals. For the aboveground parts of reeds, about 156.6 kg·ha^-1·a^-1 of zinc, 369.9 kg·ha^-1·a^-10 of copper, 32.9 kg·ha^-·a^-1 of lead and 6.5 kg·ha^-1·a^-1 of cadmium were released.

2. (2)

   The mollusca, especially C.fluminea, are the key species storing and transporting heavy metals on the food chain.

3. (3)

   The temporal change in the highest trophic level was studied and found that it was significantly related with metabolic rates. The contents of heavy metals in Dunlin reach the peaks in January and October, which are wintering season and migratory season, respectively, of the bird.

4. (4)

   Organisms often show regulation/accumulation mechanisms to different elements of heavy metals. The elements that are widely required, such as zinc and copper, are accumulated at the metabolically active parts. It is quite another thing for the other two elements. Lead was regulated well and scarcely accumulated in the bodies of macrobenthos, but cadmium was absolutely accumulated in the animals.

5. (5)

   Heavy metals were found accumulated in some parts of the bodies of these organisms, such as shells and skeletons of macrobenthos and lives and muscles of waders.

6. (6)

   All these four elements were accumulated higher in the bodies of waders than in the plants and macrobenthos, which showed a bio-magnification function of the food chain. Overall, besides the physical and chemical processes, biological processes of heavy metal elements in Yangtze Estuarine ecosystem play a very important role in self-purification function of the ecosystem. Measurement of heavy metal contents in plants and animals in the estuarine ecosystem is an efficient technology for monitoring the environmental quality of the estuary.

     

Elemental fingerprint analysis of barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis>) using inductively coupled plasma mass spectrometry,isotope-ratio mass spectrometry,and multivariate statistics

Inductively coupled plasma mass spectrometry (ICP–MS) and isotope-ratio mass spectrometry (IR-MS) have been used to examine the multi-elemental composition and ¹⁵N/¹⁴N and ¹³C/¹²C isotope ratios of three spring barley (Hordeum vulgare) genotypes (Orthega, Barke, and Bartok) grown in three typical Danish agricultural soils (North Jutland, West Jutland, and East Zealand) differing in soil fertility. The aim of the study was to examine whether it was possible to generate a unique elemental fingerprint of individual barley genotypes irrespective of the elemental imprint plants had received from soils differing in fertility and agricultural practice. Multivariate statistics were used to analyze the elemental fingerprints of the barley genotypes at different times during a full growing season from early tillering to full maturity of the barley grains. Initially, 36 elements were analyzed in the plant samples but this number was subsequently reduced to 15 elements: B, Ba, C, Ca, Cu, Fe, K, Mg, Mn, N, Na, P, S, Sr, and Zn. These elements exceeded the limit of detection (LOD) for all genotypes, soil types, and plant growth stages and for these elements the accuracy was better than 90% compared with apple leaf certified reference material (CRM). Principal component analysis (PCA) separated multi-elemental data in accordance with soil type when plants of similar physiological age were compared, whereas this separation disappeared if plants of all ages were compared simultaneously. Isotope ratios (¹⁵N) of plants also proved to be a highly accurate property for classification of samples according to soil type. In contrast, the differences in ¹³C were too small to enable such classification. The differences in ¹⁵N among soils were so pronounced that separation of samples according to the physiological age of plants became redundant. However, ¹⁵N and the multi-elemental analysis revealed no differences between the three barley genotypes, indicating that the influence of soil chemistry and possibly also climate and agricultural practice was too large to allow an unique elemental fingerprint for the genotypes. This finding was substantiated by analyzing the multi-elemental composition of grain from two additional genotypes (Otira and Barthos) grown at the north and east locations, respectively. PCA showed not only that the elemental fingerprints of these two genotypes were similar to those of the others, but also that the soil in which the plant had been growing could be accurately predicted on the basis of the PCA scores from the genotypes Orthega, Barke, and Bartok. Similar conclusions could be drawn using ¹⁵N data.     

Multitracer study on transport and distribution of metal ions in plants

Transport and distribution of metal ions in rice and soybean plants were studied using multitracers produced by irradiating an Au target by 135 MeV/nucleon¹²C,¹⁴N, or¹⁶O ions accelerated by RIKEN Ring Cyclotron. The multitracer consisted of radioisotopes of the following elements: Be, Na, Sc, Mn, Fe, Co, Zn, Se, Rb, Sr, Y, Zr, Nb, Ag, Te, Ba, Ce, Pm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ir, and Pt. Rice and soybean plants were grown in a nutrient solution and also on soil containing a multitracer. -ray spectroscopy of different parts of the plants showed that all the elements were more or less taken up by roots, while appreciable transport to leaves and seeds was observed only for Mn, Zn, Se, Rb, Sr, and Ba.     

Analysis of the chemical elements in leaves infected by fumagina by X-ray fluorescence technique

Summary Energy dispersion X-ray fluorescence technique (EDXRF) was employed to study the effects of the fumagina disease through the elementary chemical composition of leaves. The experimental setup consisted of a Mo X-ray tube (K_μ=17.44 keV) with Zr filter and a Si(Li) detector. The measurements were performed with infected and healthy leaves of citric plants. The elements Ti, Mn, Fe, Cu and Zn were quantified. For all the elements of interest the measured detection limit was at the order of mg ^. g^-1.     

<Emphasis Type="Italic">Lycopodium cernuum</Emphasis> and <Emphasis Type="Italic">Funaria hygrometrica</Emphasis> as deposition indicators for radionuclides and trace metals

Summary Levels of ²¹⁰Pb, ²¹⁰Po, ¹³⁷Cs and some trace elements (Cu, Zn and Pb) in two most common mosses (Lycopodium cernuum and Funaria hygrometrica) distributed in the eastern Mediterranean sea region (Syrian coastal mountains series) have been determined. Radiochemical analysis has shown that these plants contain high levels of ²¹⁰Pb, ²¹⁰Po, ¹³⁷Cs. The highest concentration of ²¹⁰Pb, ²¹⁰Po and ¹³⁷Cs were found to be 1450, 1322 and 1140 Bq ^. kg^-1 dry wt. in L. cernuum, respectively. F. hygrometrica was found to have higher values of ²¹⁰Pb and ²¹⁰Po concentrations and reached 2392 and 2119 Bq ^. kg^-1 dry wt., respectively. Correlation coefficients for radionuclide levels in both plants versus their levels in soil have been determined: No correlation for ¹³⁷Cs for both plants has been observed. This indicates that ¹³⁷Cs in these plants is of atmospheric origin and the plants can be used as deposition indicators. In addition, a correlation with radionuclide levels was found only for ²¹⁰Pb and ²¹⁰Po in F. hygrometrica samples and was mainly related to ²²⁶Ra content in soil and the existing faults, which are the main source of these radionuclides. On the other hand, lead concentration in L. cernuum was found to be in the range of 5-86.6 ppm, while F. hygrometrica samples were found to contain around 58 ppm. Both plants seem to accumulate lead from the atmosphere where vehicle emissions are the main source of lead in the region. Comparable concentrations of Cu and Zn were found in all plant and soil samples.     

Determination of rare earth and other elements in algae by ICP-MS and neutron activation analysis

Several rare earth elements (REEs) and other elements in algae were investigated by ICP-MS and INAA. Algae materials were supplied from an IAEA Intercomparison Study:Chlorella vulg. grown under reduced levels of toxic elements (IAEA-391) and IAEA-393 algae was grown in a medium to which certain toxic elements were added. 34–691 mg of algae samples were dissolved in conc, nitric acid using a microwave sampleppreparation system. REEs could be detected in the order of magnitude of 10⁻³ ng/g by ICP-MS. Activation analysis failed to detect any REEs because of a strong interference due mainly to²⁴Na and³²P. The distriubtion patterns of these REEs in algae slightly differed from those ofCarya sp. and tobacco leaves, and differed significantly from that of fern leaves. The distribution pattern was rather similar to that found in the North American shale composite (NASC).     

Elemental analysis of fertilizers using X-ray fluorescence and their impact on alpha radioactivity of plants

The fertilizers used for plantation contain different elements including some natural radionuclides with their daughter decay products. The radiological impact of the use of fertilizers may be due to internal irradiation of the lung by the alpha particles, short lived radon-thoron progeny and the external irradiation of the body by gamma ray emitted from the radionuclides. The aim of this study was to estimate the enhanced alpha radioactivity in different parts of plants due to fertilizers and to measure the concentration of different elements present in the fertilizers. A control study was carried out on round gourd plants using different fertilizers. Fertilizers were added to the soil just before the plantation of seeds in the pots. For the measurement of alpha track densities in different parts of plants we used α-sensitive LR-115 type II plastic track detectors. The alpha-track density (T cm^?2 days^?1) was measured in leaves of plants at different interval of time. The variation in alpha track densities was also observed in root, stem leaf and grain parts of the plants. In case of the plants grown using some phosphate fertilizers the alpha radioactivity was found to be more compared with others. A positive correlation between alpha track densities and mass exhalation rates of radon from different fertilizers has been observed. The concentration of major elements (Al, Si, P, S, Cl, K) along with other elements present in fertilizer samples was measured by X-ray fluorescence analysis.     

Development of a 14C detectable real-time radioisotope imaging system for plants under intermittent light environment

A new real-time radioisotope imaging system (RRIS) to study the kinetics of nutrient uptake and transfer of photosynthetic products in a living plant was developed and evaluated through a test run. ¹⁴C is a common radioisotope of carbon and useful to trace the photosynthetic products as well as a low energy beta emitter. The rationale of this study was to develop a RRIS that has the ability to detect low energy beta emitters, such as ¹⁴C, ³⁵S, and ⁴⁵Ca. To achieve compatibility between the detection of low energy beta emitters and irradiation of the test plant, an intermittent lighting system was added to the RRIS. Furthermore, a commercially available digital camera was added to the RRIS for acquisition of photographic images of the test plants. The capabilities of the new RRIS were evaluated through a test run by using seedlings of rice plants and ³⁵S-labeled sulfate. It was shown that the new RRIS was able to detect ³⁵S absorbed by rice plant seedlings, and it was able to acquire photon-counting images and photographic images of the test plants simultaneously. Despite some limitations, the new RRIS provides a means to study the kinetics of elements in plants by utilizing low energy beta emitters.     

Uptake and Distribution of Trace Elements in Growing Cucumber

Multitracer technique was used to study the uptake and distribution of some relatively long half-life radionuclides Be, Na, Mn, Co, Sc to growing cucumber (Cucumis Sativus L.) with two different treatments. In Hoagland solution, only ⁵⁴Mn and ⁶⁰Co accumulated in the every part of plants. ⁵⁴Mn, ⁶⁰Co and other radionuclides were absorbed in distilled water. The results indicate that there were major differences in the accumulation of trace elements between the two different treatments.     

Multi-element determination in sandstone rock by instrumental neutron activation analysis

Summary Instrumental neutron activation analysis (INAA) was used for the qualitative and quantitative analysis of sandstone samples of Aswan area, in South Egypt. The samples were properly prepared together with standards and simultaneously irradiated by a neutron flux of 7 ^. 10¹¹ n ^. cm^-2.s^-1. in the TRIGA research reactor facilities in Mainz. The gamma-spectra from a hyperpure germanium HPGe detector were analyzed. The present study provides the basic data of elemental concentrations of a sandstone rock. The following elements have been determined: Na, K, Fe, Sc, Cr, Co, Zr, Ce, La, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. Energy dispersive X-ray fluorescence (EDXRF) was used for comparison and to detect elements which can be detected only by this method.     

Application of instrumental neutron activation analysis to plant medicines in Ghana: A review

Some essential elements in eleven plant medicines used at the Center for Scientific Research into Plant Medicine (CSRPM), Mampong-Akwapim, Ghana, for the management and cure of various diseases were determined by instrumental neutron activation analysis (INAA), using thermal neutrons at a flux of 5^.10¹¹ n^.s^-1.cm^-2. The plant medicines were: Sirappac powder-E, Tina-A powder, Blighia powder, Aphrodisiac powder, Ninga powder and Lippia tea. The others are Olax powder, Ritchiea powder, Momordica powder, Kenken and Fefe powder. Concentrations of seventeen elements namely Al, Br, Ca, Cl, Co, Cu, Cr, K, Mn, Mg, Na, Rb, Sb, Sc, Ta, V, and Zn have been determined by short, medium and long irradiation times. Of these elements Co, Sb, and Sc are found to be present at the trace level, Br, Cu, Cr, Mn, Rb, Ta, V and Zn at the minor level, while Al, Ca, Cl, K, Mg and Na were generally at major level. The differences in the concentration of the elements are attributed mainly to soil composition and climate in which the plants grow. Standard reference material NIST SRM-1571 (Orchard Leaf) was analyzed simultaneously with the samples. The precision and accuracy of the method were evaluated using real samples and the standard reference material. It was found that the elemental concentrations measured in the NIST SRM-1571 were within ±10% of the reported values. The importance of these elements as related to human health and nutrition has been discussed.     

Soil-to-plant transfer of 137Cs and other essential and trace elements in cabbage plants

The concentrations of ¹³⁷Cs and other essential and trace elements were determined in soils and in cabbage heads collected from 8 agricultural fields in Aomori Prefecture, Japan and the soil-to-plant transfer factors were determined. The 95% confidence intervals of the elements, excluding ¹³⁷Cs, La and Ce, were within 2 orders of magnitude. The transfer factor of ¹³⁷Cs was approximately 4 times higher than that of Cs, and they were well correlated. In addition, the distributions of elemental concentrations in different leaf positions of a cabbage plant were also determined and were divided into three groups according to their different distribution patterns in the leaf positions. These patterns were as follows: (1) the concentrations of the elements in older (outer) leaves were higher than in younger (inner) ones (Ca, Sr, etc.), (2) the concentrations of the element had a relatively constant value independent of their leaf position (K, Rb, etc.), and (3) the concentrations of the elements were higher in both the older and younger leaves compared to the leaves in the middle portion (Zn). The percentage distribution of the dry weight contents in the edible leaves of cabbage plants was 41% at harvest time, however each element had different distribution patterns.     

Controle de la purete d'echantillons de nickel par spectrometrie-γ directement apres irradiation au moyen de neutrons thermiques

Purity control of high-purity nickel by direct γ-spectrometry after irradiation with thermal neutronsThe possibilities of analysing high-purity nickel samples by direct γ-spectrometry with a Ge(Li) detector after neutron activation are described. The samples (300—600 mg) are irradiated for 65 h in a thermal neutron flux of 5 X 10¹² n cm^-2 s^-1 and the matrix radioactivity is then allowed to decay for 30 h. It is possible to determine simultaneously 18 elements (the commonest impurities in nickel) by using standards containing known quantities of these elements irradiated under the same experimental conditions. Concentration limits are calculated for 15 elements based on the nuclear characteristics of the radio-isotopes which can be detected by neutron activation. It should be possible to determine 22 elements in nickel samples, at concentrations below 0.1 μg g^-1. The method is suitable for laboratories situated far from irradiation facilities.     

Determination of Cr(VI) in plants by electrothermal atomic absorption spectrometry after leaching with sodium carbonate

The determination of chromium (VI) compounds in plants by electrothermal atomic absorption spectrometry (ET AAS) is proposed based on their leaching with 0.1 M Na₂CO₃. Due to the presence of relatively high amounts of Na₂CO₃ in the resulting samples, the temperature and time of pyrolysis and atomization stages must be optimized to minimize the influence of the matrix. A limit of detection (LOD) for determination of Cr(VI) in plants by ET AAS was found to be 0.024 μg g⁻¹.The concentration of Cr(VI) and total chromium in plants collected in different geographical areas (South Africa and Russia), grown on soils high in chromium was determined. The concentration of Cr(VI) and total Cr in stems and leaves of plants was in the range of 0.04–0.7 μg g⁻¹ and 0.5–10 μg g⁻¹, respectively. The limited uptake of Cr(III) by plants, in comparison to its concentration in soil, can be explained by the very low solubility of natural Cr(III) compounds.Results for the determination of Cr(VI) were confirmed by the analysis of BCR CRM 545 (Cr(VI) in welding dust) with good agreement between certified (39.5 ± 1.3 μg mg⁻¹) and found (38.8 ± 1.2 μg mg⁻¹) values. The total concentration of Cr in plants has also been determined by ET AAS after dry ashing of samples at 650 °C. Results were confirmed by the analysis of BCR CRM 281 (Trace elements in Rye Grass) with good agreement between the found (2.12 ± 0.16 μg g⁻¹) and certified value (2.14 ± 0.12 μg g⁻¹).     

Determination of 137Cs, 90Sr, 40K radionuclides in food grain and commercial food grain products

Following up transfer of strontium from soil to plants requires determination of isotope in the surface layer of soil and a chosen plant. The most endangered food products are plants including commonly grown grain, which constitutes a basic feeding component for both people and animals. Indeed large amounts of ¹³⁷Cs, ⁹⁰Sr get into organisms of people and animals with the food, therefore determination of radioactivity of elements in food products and animal fodder is very essential. Choice of proper diet allows to limit the level of human organism denaturation. The aim of this paper was to study relocation of ⁹⁰Sr, ¹³⁷Cs, ⁴⁰K isotopes from soil to grain and then from grain to food products. There were investigated soil, wheat, barley, groats, flour, macaroni and breakfast flakes. Based on the obtained results there were calculated effective weighted doses [nSv] from consumption of 1 kg of a product for different age groups.     

Possibilities of using simultaneous ion-induced nuclear and atomic activation for the characterization of hair

The possibility of a simultaneous determination of low and medium Z elements in hair in a single ion beam exposure was studied. Different ion beams, proton, deuteron,³He and¹⁸O, at velocities ranging from 2.7–6.9 MeV/amu were investigated. In this work,¹⁸ ₈O⁴⁺ beam was found to give the best experimental condition in terms of sensitivity and number of elements detected. The detection limits in a single hair ranged from 2.9·10⁻⁵ μg for Fe to 0.72 μg for H using this beam.     

Determination of Rare Earth Elements in Navel Oranges from Different Geographical Regions of China by Inductively Coupled Plasma-Mass Spectrometry

There are three major production bases of navel oranges in China, including Southern Jiangxi Province, Southern Hunan Province, and the Three Gorges District of the Yangtze River. Southern Jiangxi and Southern Hunan are also famous for rare earth elements that are ionic, making them easily passed from soil to plants and fruits. To test the relative enrichment of rare earth elements in navel oranges from these production sites, ICP-MS analysis was performed following a microwave digestion procedure. The concentrations of La, Ce, Pr, and Nd in navel orange peels from Southern Jiangxi and Southern Hunan (1.26–1.86 µg g^?1) were much higher than results from the Three Gorges (0.23–0.46 µg g^?1). Moreover, yttrium is relatively enriched (0.25–0.29 µg g^?1) in navel orange peels from Southern Jiangxi at concentrations almost twice that from Southern Hunan (0.15 µg g^?1). The various concentrations and distribution of rare earth elements offers the possibility of traceability and authentication of navel oranges. Meanwhile, navel orange peels from Southern Jiangxi posed no risk in consumption, based on the maximum limit level (≤0.7 µg g^?1, wet weight) of rare earth elements in food issued in China (GB 2762-2005).