Simultaneous neutron-activation determination of selenium and mercury in biological samples by volatilization
Abstract
A method is described for the determination of selenium together with mercury in biological samples by neutron-activation analysis based on quantitative volatilization of both elements. The technique originally developed for mercury, based on pyrolysis with filtration of undesirable impurities and selective trapping from the gas phase, is now extended to selenium. The radionuclides 197Hg and 75Se, from one sample, are trapped separately and counted in a well-type NaI(Tl) detector and γ-spectrometer for maximum sensitivity. The method has been tested by comparative analyses and analyses of standard biological materials, and gives good results. It is simple and is especially effective in studies of the interaction of mercury and selenium in biological systems; a positive correlation for these elements was found for human tissues.
On décrit une méthode pour le dosage du sélénium conjointement au mercure dans les échantillons biologiques par analyse par activation de neutrons basée sur la volatilisation quantitative des deux éléments. La techniqu initialement développée pour le mercure, basée sur la pyrolyse avec filtration des impuretés indésirables et captage sélectif de la phase gazeuse, est maintenant étendue au sélénium. Les radionuclides 197Hg et 75Se, d'un échantillon, sont captés séparément dans un détecteur NaI(Tl) du type puits et un spectromètre γ pour la sensibilité maximale. La méthode a été essayée par des analyses comparatives et des analyses de produits biologiques étalons, et donne de bons résultats. Elle est simple et particulièrement efficace dans les études de l'interaction du mercure et du sélénium dans des systèmes biologiques; on a trouvé une corrélation positive pour ces éléments pour des tissus humains.
Zusammenfassung
Es wird ein Verfahren beschrieben. Selen zusammen mit Quecksilber in biologischen Proben durch Neutronenaktivierungsanalyse zu bestimmen, wobei beide Elemente quantitativ verflüchtigt werden. Das ursprünglich für Quecksilber entwickelte Verfahren der Pyrolyse mit Filtration unerwünschter Verunreinigungen und selektivem Auffangen aus der Gasphase wird jetzt auf Selen ausgedehnt. Die Radionuklide 197Hg und 75Se von einer Probe werden getrennt aufgefangen und, um die höchste Empfindlichkeit zu erzielen, in einem NaJ(Tl)-Detektor vom Bohrlochtyp und einem γ-Spektrometer gezählt. Das Verfahren wurde durch Vergleichsanalysen und Analysen von biologischem Standardmaterial getestet; es gibt gute Ergebnisse. Es ist einfach und besonders nützlich bei Untersuchungen der Wechselwirkung von Quecksilber und Selen in biologischen Systemen; in menschlichem Gewebe wurde eine positive Korrelation zwischen diesen Elementen gefunden.
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Human exposure to mercury in the vicinity of chlor-alkali plant
2009, Environmental ResearchThe main objectives of our study were to estimate the impact of a mercury cell chlor-alkali (MCCA) complex in Rosignano Solvay (Tuscany, Italy) on the local environment and to assess mercury exposure of inhabitants living near the plant. Measurement campaigns of atmospheric Hg near the MCCA plant showed that the impact of the emitted Hg from the industry on the terrestrial environment is restricted to a close surrounding area. Total gaseous mercury concentrations in ambient air of inhabited area around the MCCA plant were in the range of 8.0–8.7 ng/m3 in summer and 2.8–4.2 ng/m3 in winter. Peaks of up to 100 ng/m3 were observed at particular meteorological conditions. Background levels of 2 ng/m3 were reached within a radius of 3 km from the plant. Reactive gaseous mercury emissions from the plant constituted around 4.2% of total gaseous mercury and total particulate mercury emission constituted around 1.0% of total gaseous mercury emitted. Analysis of local vegetables and soil samples showed relatively low concentrations of total mercury (30.1–2919 μg Hg/kg DW in the soil; <0.05–111 μg Hg/kg DW in vegetables) and methylmercury (0.02–3.88 μg Hg/kg DW in the soil; 0.03–1.18 μg Hg/kg DW in vegetables). Locally caught marine fish and fresh marine fish from the local market had concentrations of total Hg from 0.049 to 2.48 μg Hg/g FW, of which 37–100% were in the form of methylmercury. 19% of analysed fish exceeded 1.0 μg Hg/g FW level, which is a limit set by the European Union law on Hg concentrations in edible marine species for tuna, swordfish and shark, while 39% of analysed fish exceeded the limit of 0.5 μg Hg/g FW set for all other edible marine species. Risk assessment performed by calculating ratio of probable daily intake (PDI) and provisional tolerable daily intake (PTDI) for mercury species for various exposure pathways showed no risks to human health for elemental and inorganic mercury, except for some individuals with higher number of amalgam fillings, while PDI/PTDI ratio for methylmercury and total mercury exceeded the toxicologically tolerable value due to the potential consumption of contaminated marine fish.
Minor and trace element contents in pituitary gland of "normal" humans: An evaluation of analytical data
2005, Microchemical JournalIn the study of trace elements in the different human brain areas, a critical evaluation of the values available in the literature is of great importance in attempting to establish reliable baseline levels, i.e., Reference Values (RVs) for toxicological assessment studies.
This paper reviews the published values of minor and trace elements in the pituitary gland (hypophysis) of “normal” humans.
Eighteen published papers are taken into account, 15 of which refer to the entire gland, whereas in three of them, only the adenohypophysis is considered.
It turns out that essential elements such as Cu, Fe, Se and Zn were more frequently determined, whereas As, Br, Ca, Co, Cr, Cs, K, Mg, Mn, Ni and Rb were seldom investigated.
Mercury was determined by several authors because of the concern caused by Hg release from dental amalgam fillings.
Most values were obtained by Neutron Activation Analysis (NAA), which appears to have played a pioneer role in this field.
Literature data on trace element levels in pituitary gland are at present insufficient to establish RVs; rather, they can be considered only as indicative values.
Future investigations based on large populations of control subjects, with standardization of the preanalytical factors and the use of fit-for-purpose Standard or Certified Reference Materials (SRMs, CRMs) should therefore be envisaged.
Mercury, selenium, and cadmium in human autopsy samples from Idrija residents and mercury mine workers
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Elemental Composition (Ca, Mg, Mn, Cu, Cr, Zn, Se, and I) of Daily Diet Samples from Some Old People's Homes in Slovenia
1998, Journal of Food Composition and AnalysisModern analytical methods such as radiochemical and instrumental neutron activation analysis (RNAA and INAA), and electrothermal and flame atomic absorption spectrometry (ETAAS and FAAS), were used to determine concentration levels of elements Ca, Mg, Mn, Cu, Zn, Cr, I, and Se in 51 carefully prepared composite samples of total daily diets from some old people's homes in different parts of Slovenia for the summer period of the year 1992. The reliability of the results was checked by the analysis of compositionally similar certified standard reference materials (SRMs). Concentration levels of all essential elements were mostly below the recommended dietary allowance values (RDA) even when only 60% of the RDA value was taken into account.
Intake of 17 Elements by Swedish Women, Determined by a 24-h Duplicate Portion Study
1998, Journal of Food Composition and AnalysisDuplicate portions of all foods and beverages consumed by 15 Swedish women during seven consecutive 24-h periods were collected and analyzed for 17 elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Se, and Zn), mainly by atomic absorption spectrophotometry after dry ashing. Considerable emphasis was placed on analytical quality assurance. For this purpose, a set of six different simulated diet reference materials, consisting of a number of foods mixed in different proportions was prepared. A procedure for performance evaluation using these reference materials was developed. The results of the study indicate that the dietary intake of essential mineral elements is generally adequate, and the intake of undesirable elements is low.
An in vitro binucleated blocked hepatic cell technique for genotoxicity testing in fish
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