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Trace elements in the water cycle of the Šalek Valley, Slovenia, using INAA
Abstract
Three watersheds were studied by sampling bulk precipitation deposition, seepage water at 50 cm soil depth and spring water. As the main analytical method for determination of trace elements and heavy metals in water samples, thek
0-based method of INAA was used. The results showed an increased content and concentration range of trace elements in precipitation, soil water and spring water in the vicinity of the otanj Thermal Power Plant. We demonstrated that thek
0-based method of INAA as a multielement nondestructive technique is a highly suitable approach to determining some toxic trace elements in environmental studies of the water cycle.
... Total Sc in suspended material, periphyton, water and artificial substrates was determined by neutron activation analysis (INAA) as described by Smodiš (1992) and Svetina et al. (1996) . This method has proved to be very sensitive for the determination of the above element, even when only small amounts of samples are available for analysis (Sansone et al., 1998). ...
Aquarium experiments were performed to quantify the inorganic fraction of suspended particles deposited on the external surface
of aquatic biota. The mass of suspended particles retained on the surfaces of microalgae growing on submerged substrates and
the algal biomass were determined by comparing the scandium content of suspended material with that in algal communities.
Scandium, a predominantly soil-associated trace element, has been used as a ‘tracer’ for the inorganic component of suspended
particles, because this element is geologically ubiquitous in soils, and it is recognized that it cannot cross natural membranes
of plants and other organisms. The algal biomass determined using the scandium content was compared with biomass values calculated
using phytopigments as estimates of periphyton biomass. The results indicate that the suspended particle mass adhering to
the external periphyton surface may accounted for up to 55% of the total mass collected on submerged artificial substrates.
... The k -based method of instrumental neutron 0 Ž activation analysis INAA; Smodis, 1992;Svetina . et al., 1996 was used for determination of total Sc and Cs in suspended material and periphyton. This method has proved to be very sensitive for the determination of the above elements, even when only small amounts of samples are available Ž . for analysis Table 1 . The accuracy of the results obtained was confirmed by the analysis of botani-Ž . Ž c ...
The retention of suspended particles transported by river flow on surfaces of freshwater plants is a potentially important process in the contamination of aquatic biota. Field experiments have been performed to test the role of benthic algae (periphyton) in trapping inorganic suspended solids transported by the river water and to discriminate between the caesium content of periphyton caused by the adherence of inorganic solids and by the active uptake inside the organisms. The contribution of caesium of suspended solids adhering to biotic surfaces was estimated by determining the scandium content (scandium method). The scandium method was used because this element is geologically ubiquitous in soils and it is not taken up actively by plants and other organisms. The mass of suspended particles retained on the surfaces of microorganisms growing on submerged substrates were determined by comparing the scandium content of suspended material with that in algal communities. Neutron activation analysis was used as the analytical method for determination for both scandium, and caesium. The results indicate that the suspended particle fraction can contribute up to 80% of the caesium contamination of periphyton samples. Active caesium uptake and accumulation by aquatic biota represents the remaining 20% of the total caesium contamination.
... Total Sc and Cs in suspended material, periphyton, water and artificial substrates were determined by neutron activation analysis (INAA) as described by Smodis (1992) and Svetina, Smodis, Jeran and Jacimovic (1996). This method has proved to be very sensitive for the determination of the above elements, even when only small amounts of samples are available for analysis (Sansone et al., 1998). ...
Suspended particle adhesion on aquatic biota can significantly increase the apparent concentration of radionuclides above their endogenous value, leading to an overestimation of the uptake rate and concentration ratios. This study is an attempt to assess quantitatively the importance of suspended particle adhesion on periphyton samples (biological material coating submerged surfaces). The concentrations of 137Cs and stable Cs (133Cs) in periphyton, suspended particles and filtered water were measured to determine the net water-to-periphyton concentration ratios for 137Cs and stable Cs. The net amount of 133Cs (or 137Cs) taken up by periphyton was calculated by subtracting from the total amount of 133Cs (or 137Cs) on the collected material (periphyton + inorganic particles), the 133Cs (or 137Cs) due to the inorganic particles adhering to periphyton. The mass of suspended particles adhering to the periphyton surface was calculated using scandium as an indicator of the mineral fraction of the suspended particles. The relationship between the concentration ratios for 137Cs and stable Cs and suspended particle adhesion on periphyton external surfaces is discussed.
The concentrations of some elements in a few varieties of cereals and pulses are determined by Instrumental Neutron Activation Analysis using a single comparator method (k0-standardised NAA method). A total of 15 elements are measured. The method was validated by analysing the Standard Reference Material (SRM-1571) of NIST; the results are within ±10% of the reported values for the majority of the elements. The measured concentrations of major and minor elements are analysed in terms of the average intake of mineral content and the role of these elements in terms of the nutritional value.
The International Atomic Energy Agency (IAEA) was formed in 1957 as a specialised agency within the United Nations system for scientific and technical co-operation in the nuclear field. Its Statute authorises it, among others, “… to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world”. Since its foundation, therefore, the IAEA has been supporting the use of nuclear analytical techniques such as neutron activation analysis, particle induced X-ray emission and X-ray fluorescence, for undertaking environmental monitoring and assessment activities ever since founded. Research work on trace element air pollution has been systematically supported since 1992. The activities supported include mainly (1) collection and analysis of coarse (2.5–10 μm diameter) and fine (<2.5 μm diameter) airborne particulate matter using standardized low-volume stacked filter air samplers and (2) trace element atmospheric pollution studies using plants as biomonitors. The IAEA has two main support tools for its Member States: the Research Contract Programme for encouraging research of interest to the IAEA's programme of work based on its mandate, and the Technical Co-operation Programme focused on solving technical problems by providing the necessary know-how upon countries' requests. Basic mechanisms and functions of both tools are presented. In supporting assessment of chemical elements in atmosphere the IAEA is implementing environmental metrology in practice: First, available environmental monitoring and assessment tools are adopted, upgraded and tested within co-ordinated research projects. Once tested, these tools are transferred to developing countries through technical co-operation projects. Projects on studying element atmospheric pollution, emphasising the one on “Validation and application of plants as biomonitors of trace element atmospheric pollution, analysed by nuclear and related techniques”, are presented. In the framework of this project, the participants are harmonizing approaches for using plants for the assessment of atmospheric element deposition. Production and characterization of reference materials, and organization of quality control exercises form an important part of IAEA continuous support to its Member States in achieving high quality measurement results. Recent activities pertaining to the assessment of chemical elements in the atmosphere are presented. These activities include production of reference lichen material IAEA-336, and organisation of five proficiency testing and analytical quality control exercises involving air filters and plant materials, coded NAT-3 to NAT-7.
The paper reports the approach followed in the SOILSAMP project, funded by the National Environmental Protection Agency (ANPA)of
Italy. SOILSAMP is aimed at assessing uncertainties associated with soil sampling in agricultural, semi-natural, urban, and
industrial environments. The uncertainty assessment is based on a bottom-up approach, according to the Guide to the Expression
of Uncertainty in Measurement published by the International Organization for Standardization (ISO). A designated agricultural
area, which has been characterized in terms of elemental spatial distribution, will be used in future as a reference site
for soil sampling intercomparison exercises.
The concentration of trace elements was studied in different parts of the submersed species Najas marina and Potamogeton lucens and in floating-leaved species Nuphar lutea and Potamogeton nodosus, and also in the corresponding samples of water and sediment in the artificial lake Velenjsko jezero, where the large amount of ash from lignite coal (about 15 million tons) is deposited at the bottom. The concentration of trace elements in water was mainly below the detection limit. In sediment only the concentration of As was found to be above the average European background concentration. It also showed the highest degree of translocation from sediment into plant roots, but its mobility to above-ground plant parts was negligible. The submersed species N. marina and P. lucens exhibited similar concentrations of trace elements in their organs. Of the floating-leaved species, the lowest concentrations of trace elements were found in N. lutea and the largest in P. nodosus. Significantly higher concentrations of As, Ni, Pb and Cr were shown in roots of N. marina, P. lucens and P. nodosus than in their stems and leaves, whereas Cu and Zn were equally distributed throughout all their organs. Cr and Ni also showed relatively high mobility from roots to upper parts of N. lutea.
The k0-standardization method of INAA (instrumental neutron activation analysis) was applied to three reference materials: NIST (National Institute for Standards and Technology, Washington, D.C., USA) SRM (Standard Reference Material) 1646 Estuarine Sediment, NIST SRM 2704 Buffalo River Sediment and IAEA (International Atomic Energy Agency) CRM (Certified Reference Material) SL-1 Lake Sediment. Among the 50 elements sought yielding long-lived radioisotopes after (n, ) activation, for 32 elements numerical values were obtained, and for the remaining 18, only detection limits were estimated. When comparing the results obtained in this work to certified, recommended or other literature values, good agreement was found, proving that the same analytical procedure can be applied with confidence for analysis of environmental sediment samples.
The ko-standardization method is suitable for routine multielement determinations by reactor neutron activation analysis (NAA).
Investigation of NIST standard reference materials SRM 1571 Orchard Leaves, SRM 1572 Citrus Leaves, and SRM 1573 Tomato Leaves
showed the systematic error of 12 certified elements determined to be less than 8%. Thirty-four elements were determined in
NIST proposed SRM 1515 Apple Leaves.
Source receptor relationships are presented for trace elements emitted from various sources in Europe and measured at a number of remote locations. Quantitative and qualitative data for the major sources of trace elements in Europe are presented, and the emission data have been used in long-range transport models to calculate trace element concentrations and deposition patterns. These estimates are verified by measurements, and a few examples are given. It was concluded that the estimates of trace element emissions can be related to the air concentrations measured at remote locations. Statistical methods were found useful to assess the source category of trace elements measured at remote locations. However, it has been proven much harder to localize the sources. To do so, it is necessary to use these techniques together with the information on the meteorological situation, particularly on air mass trajectories and/or synoptic configurations, and accurate emission inventories.
Defining ecology as a system-theory oriented synthesis of both Earth and life sciences, this study aims at a coherent understanding of the chemical impact on the lower atmosphere and the characteristic types of terrestrial ecosystems. To this end, comprehensive flux-analytical and hierarchical modelling approaches were developed and consulted, which include a consideration of the specific physical and geographic boundary conditions of the processes involved. The first part of the text is devoted to fundamentals of environmental chemistry and ecology, while the second deals with the complex atmospheric pathways of anthropogenic chemicals. In the last part, the manifold interactions of these compounds or their metabolites with a soil-vegetation complex of ecosystems are described. Chapters on the impact of pollution on materials and a review of chemical fate modelling are included.
Although k0-factors and related nuclear data for 122 radionuclides of interest in (n,γ) reactor neutron activation analysis have been tabulated, there are still some reactions attracting interest with respect to the accuracy of the literature data. The present paper deals with the reaction130Ba(n,γ)131Ba, for which a more accurate half-life is proposed, together with re-evaluated Q0 and k0 factors. The new values are 11.53 days for T, 21.3 for Q0, and for the k0's 3.90×10−5, 2.75×10−5, 1.92×10−5 and 6.48×10−5 for the γ-rays at 123.8 keV, 216.1 keV, 373.2 keV and 496.3 keV, respectively.
k0-Factors and related nuclear data are tabulated for 112 radionuclides of interest in (n, γ) reactor neutron activation analysis. Whenever relevant, critical comments are made with respect to the accuracy of literature data for e. g. isotopic abundances, half-lives, absolute gamma-intensities and 2200 m · s−1 (n, γ) cross-sections. As to the latter, a comparison is made with the values calculated from the experimentally determined k0-factors, by introduction of selected literature data for the input parameters.
This paper reports on the contribution made by some cooperating laboratories to the further development of the k0-method. As to the extensions and improvements, emphasis is put on the availability of an Al–0.1% Au reference material for the k0-standardization of NAA, on the counting of large-diameter samples, on the use of a low-energy photon detector, and on the introduction of the Westcott formalism for the handling of non-1/v (n, ) reactions. A survey is given of a large variety of scientific and industrial applications, including the analysis of biological, geological and geochronological samples, various kinds of reference materials, high-purity products and ceramics, and a number of environmental pollution indicators. As shown, the advantage of the k0-standardization will be fully exploited with an increasing level of automation in NAA laboratories. Eventually, new measurements and evaluations of k0-factors and related nuclear data are given in an Appendix.
The program ROMOS and the assisting program RECAL are presented. These programs were designed to facilitate nuclide identification and concentration calculation in NAA using the k0-concept. For nuclide identification classical tests (energy match, decay factor) are complemented with a test of the saturation factor including the sensitivity of neutron acctivation analysis for the candidate nuclide. For nuclides emitting more than one gamma-energy the intensity of the observed peaks in the spectrum are compared. Thereby full account is taken of relative detection efficiency and true coincidence effects. Practical experience in using the interactive code shows that it is a convenient and time-saving working aid for an experienced experimenter.