Study of the diffusion of trace elements and radionuclides in soils

Thin layer method of measuring diffusion processes was modified to shorten time and to increase efficiency of experiments. For this purpose small and fine glass capillaries of 20 mm length and inner diameter of several millimeters were used as diffusion cells. The diffusion of trace amounts of¹³⁷Cs, its dependence on soil moisture and interaction with the soil have been studied. Experimental technique. evaluation of records and the basic interpretation of the migration process are described.     

Role of mineralogical structure of sediments in accumulation of radionuclides and trace elements

Similar distributions for ²³⁸U, ²³²Th, ²²⁶Ra, ²¹⁰Po, ^238,239,240Pu, ¹³⁷Cs and trace elements were obtained in sediment samples collected along the Romanian sector of the Danube River and the Black Sea coast during 1994. The radionuclide and trace element accumulation in the investigated samples is discussed with respect to their geochemical behavior and the mineralogical structure of the samples. The latter, investigated by X-ray diffraction and cation exchange capacity of the same samples, proves to be an important factor in the selection of sampling sites for monitoring the pollution of river basins and the sea.     

Some peculiarities of the contamination with radionuclides and toxic elements of the Syrdarya river basin, Kazakhstan

Investigation of radionuclide and element composition of environmental objects such as soil, bottom sediments, water, vegetation sampled at the Syrdarya river basin in Kazakhstan is presented. Distribution and season variations of radionuclide content for various objects were studied. Main sources of Syrdarya river contamination were revealed: the tributaries Keles and Badam, Shieli uranium field. This revised version was published online in August 2006 with corrections to the Cover Date.     

Determination of some trace elements in natural and fertilised Libyan soils using INAA and ED-XRF

Samples of natural and fertilised soils were collected from Al-Gheran region, west of Tripoli, Libya. The samples were investigated by means of INAA and ED-XRF for Al, Si, K, Ca, Sc, Cr, Mn, Fe, Co, Zn, Br, Rb, Sr, Y, Zr, Nb, Cs, Ba, Hf, Ta, Pb and Th. The results indicate that the concentrations of K, Ca, Zn, Sr and Pb are 2–4 fold higher in fertilised compared to natural soil, while the concentrations of Al, Si, Cr, Mn, Fe, Co, Rb, Y, Nb, Cs, Ba Ta and Th are nearly the same in all samples. Mn and Fe values in two arable soils have been found to be 4–6 times lower than the average concentration in the earth's surface soils. This study concludes that, although the levels of some trace elements important for human health are very low in both natural and fertilised soils. Further research is needed to understand the full significance of the distribution transfer and toxicity of trace elements introduced in imported fertilisers.     

Distribution of radionuclides and elements in Cubatão River sediments

Summary Cubat?o River is located in Santos Basin, S?o Paulo State, Brazil. This region is characterized by the occurrence of estuaries and mangrove. Due to its location, near the coastal line, it is also an important industrial area, where phosphate fertilizer plants, petrol refineries, and chemical and steel industries are present. Such human activities contribute to the enhancement of elemental composition in sediments and, in some cases, also increase the radionuclide concentrations, the so called Technologically Enhanced Natural Occurring Radioactive Materials (TENORM). The contamination of land and sediments by TENORM is of major concern. The activity concentration of U and Th series radionuclides was determined in five sediment samples from Cubat?o River. The activity concentration ratio was also determined. Equilibrium was observed for the ratio ²³⁴U/²³⁸U. The activity ratios of Th/²³⁸U, ²²⁸Ra/²²⁶Ra and ²¹⁰Pb/²²⁶Ra were higher than the unity. In the first two cases, the observed values are due to the higher activity of Th in the sediment and in the last case are probably due to the atmospheric deposition of ²¹⁰Pb.     

Assessment of metals and trace elements in sediments from Rio Grande Reservoir,Brazil, by neutron activation analysis

The Rio Grande Reservoir, Southeast of the São Paulo Metropolitan Area, supplies water for four counties (about 1.6 million people). It has been seriously affected by urban expansion due to chaotic urban occupation and improper use of the surrounding areas. In this study bottom sediment samples were collected during the dry season and rainy season. Four sampling points were defined and located at the mouth of the Rio Grande and Ribeirão Pires Rivers (points 1 and 2), in the middle of the reservoir (point 3) and near the catchment point of the water supply (point 4). Samples were submitted to instrumental neutron activation analysis and some metals, trace and rare earth elements were determined. The methodology validation according to precision and accuracy was carried out by reference material analyses. The results obtained were compared to earth crust values and also with results already published in the literature. The enrichment factor in relation to earth crust values using Sc as reference element was calculated and a strong enrichment was found for the elements As, Br, Sb, Th, U and Zn. A strong anthropogenic influence was observed for some elements, mainly in the points located in the entrance of the reservoir that receives domestic and industrial effluents from the rivers that reach the reservoir.     

Distribution of some natural and anthropogenic radionuclides in Sudanese harbour sediments

The distribution of some natural and anthropogenic radionuclides (²²⁶Ra,²²⁸Ra,²¹⁰Po,⁴⁰K,¹³⁷Cs) in surface marine sediments from the harbours at Port Sudan and Sawakin on the Sudanese coast of the Red Sea has been investigated using α-spectrometry and direct high-resolution γ-spectrometry. The prime ams were to assess the levels of radioactivity and the influence of factors such as dredging and the organic matter content of the sediments on the distribution pattern of the radionuclides. The results have been evaluated and the leves indicate the absence of any possible enhancement by anthropogenic influx from the hinterland. The spatial distribution pattern is more heterogeneous in Sawakin harbour where some parts have recently been dredged and the sludge is removed to maintain the required depth. The data also show an insignificant relationship between the activity concentrations of all the radionuclides and the content of organic matter in the sediments.     

Lognormal distribution of natural radionuclides in freshwater sediments and coal-ash repositories

The distribution of natural radionuclides,⁴⁰K,²²⁶Ra, and²³²Th, in freshwater sediments and in coal-fired power-plant ash repositories has been tested for lognormality. Thereafter, lognormality for natural radionuclide concentration frequency distribution was accepted with a high probability. The lognormal natural radionuclide distribution in sediments and coal-ash indicated single population groups. The anthropogenic modifications of the natural radionuclide concentrations in the environment are indicated. The adsorbed dose rates, in mGy y^–1, in air from gamma field of the natural radionuclides were calculated.     

Plutonium in soils, bottom sediments and lichen near peaceful nuclear explosion sites in the Republic of Sakha (Yakutia)

During the 1974–1987 period 12 paceful nuclear explosions were conducted in the Republic of Sakha (Yakutia). For the first time^239,240Pu and²³⁸Pu concentrations were determined in samples of soils, bottom sediments and lichen taken at the Craton-3 and Crystal nuclear explosion sites. At the Craton-3^239,240Pu concentrations in the range 6.2 mBq/g to 5.9 Bq/g samples of soil and^239,240Pu concentrations up to 7.4 Bq/g in samples of lichen were observed.^239,240Pu concentration measurements in bottom sediments of a stream washing out the banking around the borehole of Craton-3 show that plutonium migrates in the direction of the Markha river. At the Crystal site local plutonium concentrations up to 35 Bq/g in soil and 1.8 Bq/g in lichen were observed.     

The spectrographic determination of trace elements in rocks,minerals and soils

Summary The total content of trace elements in rocks, minerals and soils is determined by a semi-quantitativecathode layer arc spectrographic technique. For more accurate determinationsa variable internal standard technique, in which the trace element contents are compared with that of iron, is employed. This method is combined with a chemical concentration for the analysis of extracts of soils and plant materials. The chemical concentration technique involves the use of 8-hydroxyquinoline, tannic acid and thionalide, and gives recovery of microgram quantities of most trace elements, rejecting at the same time the alkalis, alkaline earths and phosphate.

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Zusammenfassung Der Gesamtgehalt von Spurenelementen in Gesteinen, Mineralien und Bodenproben wird nach einem halbquantitativen Verfahren bestimmt; hiezu werden die Proben in gehöhlten, als Kathoden geschalteten Elektroden im Bogenstrom verbrannt. Für genauere Bestimmungen wird nach einem abgeänderten Verfahren der quantitativen Spektralanalyse die Menge des Spurenelementes der Probe in Bezug auf ihren Eisengehalt ermittelt. Diese Methode ist mit einer chemischen Anreicherung für die Untersuchung von Bodenextrakten und Pflanzenmaterial kombiniert. Die Technik der chemischen Anreicherung beruht auf der Verwendung von 8-Oxichinolin, Gerbsäure und Thionalid; auf diese Weise lassen sich Mikrogramme der meisten Spurenelemente ermitteln, bei gleichzeitiger Abscheidung der Alkalien, Erdalkalien und Phosphate.

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Résumé La teneur globale des traces d'éléments dans les roches, les minéraux et les sols, est déterminée par une technique semi-quantitative, spectrographique d'arc à couche cathodique. Pour les dosages plus précis, on emploie une technique à étalon interne variable dans laquelle les teneurs en traces sont comparées à celles du fer. Cette méthode est combinée avec une concentration chimique pour l'analyse des extraits de sols et de végétaux. La technique de concentration chimique comporte l'emploi d'oxine, d'acide tannique et de thionalide et permet de récupérer des quantités de l'ordre du microgramme de la plupart des éléments en traces, ce qui élimine simultanément les alcalins, les alcalino-terreux et les phosphates.

     

Seasonal variation of natural radionuclides and some elements in plant leaves

Leaf and aerosol samples were monthly collected in Mt. Sefuri (Fukuoka Prefecture). Radioactivities of ⁷Be, ²¹⁰Pb and ⁴⁰K were determined with gamma-ray spectrometry. The concentrations of some elements in the leaf samples were determined by neutron activation analysis. Similar seasonal variation of ⁷Be and ²¹⁰Pb was observed between leaf and aerosol samples, high in spring and winter and low in summer. Correlation factors for trace elements contained in the leaf show large variations. This indicates that the contribution of two sources (atmospheric deposition and uptake from soil) is very variable.     

Determination of major,minor and trace elements in Iraqi vegetable samples by INAA

Our aim was to discover a method of separating zirconium(IV) and uranium(VI) from solutions. It is known that Zr(IV) and U(VI) are effectively extracted by tertiary amines from weak acidic sulfate solutions but the possibility of extraction decreases with increasing acidity. The transition from tertiary amine to primary amine Primene JMT enables the extraction of Zr also from more acidic solution. If both Zr and U are present in an aqueous solution, Zr is extracted preferentially and only the free part of the amine can convert uranium to an extract. The separation described below was carried out by preferentially stripping zirconium from the organic phase. The application of nitrate solution (2M HNO₃) to eliminate Zr from the solvent was tested. This method does not demand any special regeneration of the extraction agent and the amine nitrate, formed in the organic phase, can be used for further extraction of Zr without modification. Using this method of separation, a solution for producing pure ZrOCl₂·8H₂O was obtained.     

Activity concentration of some anthropogenic radionuclides in the surface marine sediments near the Saudi coast of the Arabian (Persian) Gulf

Activity concentrations of some anthropogenic radionuclides (⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239+240Pu and ²⁴¹Am) have been measured in the surface of marine sediments along the Saudi coast of the Arabian (Persian) Gulf. The samples were collected at different locations and water depths. The spatial distribution of the concentrations of the measured radionuclides showed a heterogeneous pattern and is independent of location or water depth. The obtained results are discussed and some conclusions are drawn.     

The status of trace and minor elements in some Bangladeshi foodstuffs

An investigation is conducted on the status of trace and minor elements in some foodstuffs (cereals, vegetables, milk, egg and fish), commonly consumed in Bangladesh, using proton induced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques. In PIXE measurements, the samples were irradiated in air with 2.0 MeV (energy on the target) protons having the beam intensity of 30 nA for characteristic X-ray excitation, while in XRF analysis, the samples were excited for 5000 seconds with a 10 mCi Cd-109 annular X-ray source. The elemental concentration of K, Ca, Mn, Fe, Ni, Cu, Zn, Se, As, Br, Rb, Sr, Mo, and Pb were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The validity of the analytical procedures (PIXE and XRF) followed in this study has been confirmed by comparative measurements of Cu, Zn and Mn in some varieties of rice with atomic absorption spectrophotometry. The results indicate that none of the food regimes investigated here is burdened with heavy metals beyond permissible limits except five species of vegetables with chromium having the range of 0.99–3.59 mg/kg compared to the literature value of 0.0–0.36 mg/kg (dry weight basis). An average value of 0.2 mg/kg of arsenic was observed both in IRRI (n=16) and local Aman (n=12) varieties of rice and only one hen egg contained 1.7 mg/kg of lead in yolk. The zinc content in some marine fish from Bay of Bengal was reported to be 5.4–19.5 mg/kg, whereas in the present study of sweet-water fish, the level is found to be 15.2–62.1 mg/kg (fresh weight basis) for five species. In human milk, both Cu (0.12–0.25 mg/l, n=8) and Zn (0.28–1.80 mg/l, n=8) levels appear to be almost half the literature values (n=25). On the other hand formula milk has higher values of Cu (0.32–1.63 mg/kg, n=16) and Zn (5.16–19.8 mg/kg, n=16).     

Distribution of trace and minor elements in hungarian spice paprika plants

Detailed investigations were carried out to study the distribution of trace and minor elements in different parts (fruit, seed and rib, peduncle, stem, leaf, root) of ripe Hungarian spice paprika plants. Two varieties of paprika plants were analyzed for their Cl, Co, Fe, K, Mg, Mn, Na, Rb, Sc, V and Zn content by non-destructive neutron activation analysis. The results showed that the iron contents of the samples were much higher than those of the other trace elements. For the trace elements Co, Fe, Mn, Sc, V and Zn a considerable enrichment was observed in the leaf, while the Rb and K, Na, Mg showed accumulation mainly in the peduncle. In the other parts (fruit, seed and rib, stem) of the paprika plants no significant enrichment of trace elements was found. Since some of the elements investigated may have been partially eluted during the cleaning of the roots with distilled water and, on the other hand, if the cleaning was not intensive enough, some soil particles could be retained on the samples, the data obtained for the roots should be considered with precaution.     

Level of some minor and trace elements in Bangladeshi meat products

An investigation on the level of some minor and trace elements in some varieties of meat (beef, mutton and chicken) consumed in Bangladesh is reported. In this study, protoninduced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques were used for analytical measurements. In PIXE measurements, the samples were exposed to the proton beam in air as 1 mm thick pellets and irradiated with 2.0 MeV protons having the beam intensity of 30 nA for characteristic X-ray excitation, whereas in XRF, the samples were excited for 5000 seconds with a 10 mCi¹⁰⁹Cd annular X-ray source. The elemental concentrations of Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb and Sr were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The significance of the results is dicussed in relation to human health and diseases.This research received financial support from the International Atomic Energy Agency, Vienna, under the research contract RC-4265/RB.     

Determination of trace and minor elements in Mexican cigarette wrapping paper

The concentration of 14 elements in cigarette wrapping papers used in manufacturing 21 different Mexican cigarette brands was measured using instrumental thermal neutron activation analysis. These elements are As, Ba, Ce, Co, Cr, Cs, Fe, K, Na, Rb, Sb, Sc, Sr, Th and Zn. The concentration of the elements was compared with the reported concentration in similar studies for elemental content in Pakistani, American, Chinese, Egyptian, Jordanian and Iranian cigarette wrapping papers.     

Correlation of natural and artificial radionuclides in soils with pedological,climatological and geographic parameters

Various types of soil samples were collected in the southern part of Brazil, with depth intervals of 5 cm, down to 50 cm, using a specially designed sampler. Pedological analysis of these soils were performed. Nuclear activities of¹³⁷Cs (expressed in Bq m^–2) and radioactive natural element (²²⁶Ra,²²⁸Ra and⁴⁰K) concentrations were determined by low background gamma-ray spectrometry.¹³⁷Cs concentrations were correlated with radioactive natural element concentrations and pedological, climatological and geographic parameters related to the soil samples collected.     

Characterization of a potato reference material for major, minor and trace elements

Summary A potato reference material (RM) was prepared for the analytical quality control program to be employed by the Sub-network on Trace Elements in Food of the FAO European Co-operative Network on Trace Elements. Approximately 50 kg of commercially available potato granules prepared from baked, mashed and roller-dried potatoes, containing 2.8% ash and 3 mg/kg added butylhydroxyanisole was purchased. The granules were carefully homogenised in large glass cylinders followed by division into 50 g portions into numbered acid-washed bottles. The bottled material was tested for homogeneity by taking ten bottles throughout the bottling line and determining by validated atomic absorption spectrometric methods 1.0 g samples for seven mineral elements. Homogeneity for Mg, Ca, Zn, Fe, Mo, Ni and Cd was better than 5%. An international network on experienced, high-quality reference laboratories was established to conduct an interlaboratory comparison study on the determination of 14 mineral elements in the RM. A total of seven methods based on independent analytical principles were employed by the reference laboratories. After excluding outlying analytical results, the criteria defined by the IAEA were used for classification of the overall medians obtained through the interlaboratory comparison study. The relative standard deviations for the 95% confidence limits of the medians were as follows: P=4.2%, K=0.7%, Na=4.7%, Ca=5.5%, Mg=2.4%, Fe=9.3%, Mn=4.0%, Zn=3.6%, Cu=4.7%, Mo=23%, Ni=22%, Cr=19%, Pb=11% and Cd=4.6%. With the exception of Cr, all of the recommended concentration values obtained for the above indicated elements fell into category A, i.e. values recommended with a high degree of confidence according to the classification criteria of the IAEA. The present RM is the only certified potato RM currently available for mineral elements.

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Charakterisierung eines Kartoffel-Referenzmaterials für Haupt-, Neben- und Spurenelemente