Determination of elemental composition of airborne dust and dust suspended in rain

To clarify the magnitude of wash-out effect of rain on the elemental composition of airborne dust and the possible origin of the dust, the dust samples were collected with a high-volume air sampler at the JAERI-Tokai. The dust suspended in rain was also collected from rain by filtration. Up to 20 elements in both types of the dust were determined by instrumental neutron activation analysis. It was found that the elements determined could be classified into 3 groups from the elemental composition and the elemental correlation in both types of the dust samples.     

A comparative study on the nitrate determination in airborne dust

Summary Two analytical methods for determination of nitrate in airborne dust samples — spectrophotometry and direct potentiometry with ionselective electrodes — are compared. Different aerosol samples collected by an impaction cascade device and a high-volume filter sampler and model powdered dust samples were analysed. It was shown that direct potentiometry is quite satisfactory for nitrate determination irrespective of collecting technique if the known addiMikrochim. Acta 1977 II-6 tion procedure is used. The spectrophotometric determination of impaction-collected aerosol samples suffers from interference by the copper foil used for collection. The advantage of the spectrophotometric method is that concentrations as low as 0.25g/ml can be determined reliably. The advantage of potentiometry is that it gives a simple analytical technique for samples containing down to 1 ppm NO₃ ^– and it can readily be automated.

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Zusammenfassung Zur Bestimmung von Nitrat in Staubproben wurden die UV-Spektrophotometrie und die Direkt-Potentiometrie mit ionenselektiven Elektroden verglichen. Die Untersuchung erfolgte an standardisierten Staubproben und an Proben, die mit High Volume Filter Samplern (Sartorius) und mit Kaskadenimpaktoren gesammelt worden waren. Die Direktpotentiometrie konnte bei alien mit verschiedenen Methoden gesammelten Stauben erfolgreich mit einem Standardadditionsverfahren eingeScizt werden. Die UV-spektrophotometrische Methode konnte bei den Impaktorproben nicht eingeScizt werden, da die Sammlung auf Kupferfolien erfolgte und Kupfer die Bestimmung stört. Der Vorteil der UV-Spektrophotometrie liegt in der Bestimmung sehr kleiner Nitratmengen (bis 0,25g/ml). Der Vorteil der ionenselektiven Elektroden liegt hingegen in der einfachen analytischen Vorgangsweise bei Proben bis zu 1 ppm Nitrat.

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On leave from Faculty of Chemistry, University of Sofia, Sofia, Bulgaria.     

Estimation of possible airborne elemental inputs to the Slovenian marine environment

In evaluation of the influence of environmental pollution on the ecosystem, data about the elemental concentrations of the atmospheric aerosols, combined with information about particle size and meteorological data, are of significant importance. They are also necessary prerequisites for source/receptor studies and long-range transport modeling. As such, these data are irreplaceable for the estimation of potential elemental input from air to the sea, an understanding of which is one of the tasks of the Mediterranean Pollution Programme (MED POL). Three sampling locations (Sečovlje, Koper, and Iskrba) in Slovenia were chosen for the present study, two at the coast and the third one in a scarcely inhabited, almost unpolluted area, as a reference point, and the element concentrations in the collected particulate matter (PM) were determined. From the Iskrba data the wet scavenging coefficient of airborne sulphur due to precipitation was estimated as k = (1.0±0.3)·10⁻⁴s⁻¹ (at 1.5 mm·h⁻¹).     

Reaction of palladium bisacetylacetonate with elemental phosphorus. Effect of water on the composition of palladium phosphides

Reaction of palladium bisacetylacetonate with elemental phosphorus in an inert atmosphere is shown to proceed as a redox process forming palladium phosphides of different compositions: PdP₂, Pd₅P₂, Pd_4,8P, and Pd₁₂P_3,2. The conversion of Pd(acac)₂ and the composition of palladium phosphides formed in benzene is established to be affected by water. A tentative scheme of the formation of palladium phosphides is suggested.     

Effect of bombardment with helium ions on the molecular-topological structure and elemental composition of the surface of polytetrafluoroethylene

Irradiation of a polytetrafluoroethylene (PTFE) film with accelerated (1–5 MeV) helium ions at a fluence of 10¹⁵ ion/cm² has been studied. The efficiency of carbonization, defined as a decrease in the fluorine content and an increase in the carbon content on the surface of the polymer, increases with the incident ion energy. A characteristic feature of the topological structure of PTFE is the presence of four high-meltingpoint crystalline modifications, the “branching points” of the pseudo-network of the amorphous matrix block, in addition to a low-melting-point modification with the melting onset temperature of 13°C. After bombardment with 3–5 MeV ions, only two crystalline blocks remain in the polymer and a cluster block, which was not present in the unirradiated polymer, appears. The overall mass fraction of the crystalline structure in the irradiated polymer (0.48) is below that in the initial polymer (0.66), indicating amorphization of its structure.     

Assessment of elemental contamination in road dust using EDXRF

Road dust samples were collected in different locations of heavy traffic, medium traffic, express way and industrial areas of Mumbai. The concentrations of various elements (Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb) in road dust samples were analyzed using EDXRF. The average elemental profile of road dust in Mumbai was comparable with studies carried out in other countries with slight variations. The estimated geo accumulation indices and enrichment factors indicated moderate elemental contamination and enrichment of anthropogenic elements in road dust samples. Factor analysis of elemental data resolved four sources namely crustal, tyre wear, vehicular/industrial emissions and break wear.     

Critical review on the development of analytical techniques for the elemental analysis of airborne particulate matter

Among all environmental pollutants, particulate matter (PM) poses the major threat to our health. These tiny airborne particles vary in shape and composition, which is reflected in their hazardous potential. The particles are small enough to penetrate deep into the lungs and even enter the bloodstream, causing severe diseases. Therefore, their regular monitoring is required. Toxic metals and other elements are often measured by regulatory agencies as well as in research laboratories, either to compare ambient concentrations with prescribed limit values or to study provenance of air pollution sources in order to target PM pollution mitigation strategies. The most established method for the determination of regulated Pb, Cd, As, Ni and other elements in PM is microwave digestion inductively coupled plasma mass spectrometry (MW/ICPMS), whereas X-ray fluorescence (XRF) techniques have also often been used, especially in research. In this review paper we critically assess these two and three other analytical techniques (i.e., LA-ICPMS, PIXE and INAA) for element determination in PM deposited on filter media. All aspects from sample treatment to measurement range and limitations, costs and waste management are considered. In conclusion we identify XRF and LA-ICPMS as two promising surface techniques for the analysis of a PM deposit on a filter, which could replace the laborious wet MW/ICPMS method, which is – considering its wide use, very incriminating to the environment. In short, EDXRF is the cheapest, simplest for use and already customized for PM samples, whereas LA-ICPMS is promising, but still needs some development in the direction of autosamplers and matrix-matched standards for calibration.     

Variation of the elemental composition of plants and soils

INAA with thermal and epithermal irradiation has been applied for determination of 40 chemical elements in soils and different organs of plants. The time and spatial variations of elemental composition of plants and soils are studied.     

Long-term stability of the elemental composition in biological materials

Summary Lyophilized and radiation sterilized biological certified reference materials (CRMs) are believed to be stable in their chemical composition. Generally, the certifying agencies consider the certificates of these biological CRMs valid for a 5-year shelf life, i.e., apart from measurable moisture content, the chemical composition should not change during that time. The long-term behavior of fresh frozen material is not known. In this study the elemental compositions of the Bovine Liver Standard Reference Material (SRM 1577) and human liver tissue samples are evaluated over a time period of more than 7 years. The concentrations of selected elements were determined by neutron activation analysis at various times. The initial evaluation of zinc, selenium and arsenic results gives no indication of changes during 7 years storage of fresh frozen tissues, however, a trend towards lower arsenic concentrations has been observed in SRM 1577 during a 10-year period.

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Langzeitstabilität der Elementzusammensetzung in biologischen Materialien

     

Potentiometric determination of chloride and bromide in airborne dust

Summary A simple, rapid and reproducible potentiometric titration method for determination of both bromide and chloride in airborne dust is described. The use of a precise microburette and a differentiating recorder allows good resolution of the two species determined. The method can be easily applied for routine environmental control analysis.

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Zusammenfassung Die Anwendung eines einfachen, schnellen und reproduzierbaren potentiometrischen Verfahrens zur Bestimmung von Bromiden und Chloriden in Stauben wurde beschrieben. Der Einsatz einer Motorkolbenbürette für die relativpotentiometrische Titration und die Verwendung eines Differentiators erlauben eine exakte Bestimmung des Titrationsendpunktes und ermöglichen so das gute Auflösungsvermögen des Verfahrens. Die Methode wurde routinemäßig in der Umweltanalytik eingesetzt.

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On leave from Faculty of Chemistry, University of Sofia, Sofia, Bulgaria.     

Comparison of extracting solutions for elemental fractionation in airborne particulate matter

It is here described the comparison of extraction efficiency of some solutions (acetate buffer, deionized water, diluted HNO₃ and EDTA) frequently adopted in literature for evaluating the elemental solubility in airborne particulate matter. This comparison was performed considering the distribution of As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, S, Si, Sb, Sn, Sr, Ti, V, Zn between the extractable and mineralized residual fractions on the NIST 1648 certified material, PM₁₀ real samples and size-segregated samples, collected by a 13-stage impactor.The extracting solutions were evaluated by comparing extractive efficiencies and robustness towards some factors, such as acidity and concentration of complexing species, that have great environmental variability and that could be able to modify the extractive efficiency.Furthermore, extraction methods application to size-segregated samples allowed estimating the selectivity of extracting solutions towards dimensionally characterized emission sources, as dusts originated from abrasion and road dust re-suspension.On the basis of the obtained results, it was possible to define the main advantages and disadvantages resulting from the use of different extracting solutions, necessary to make possible the comparison of environmental studies carried out in different extractive conditions and to start up a proper study for harmonizing extracting procedures.     

Cluster analysis of the elemental composition of five austrian peats

The elemental composition of peat depends on the plant residues from which the peat was formed. The concentrations of 45 elements were determined for five peat samples by plasma emission spectrometry. Literature data on the composition of three bogs was added. The elemental abundances of six rock or soil categories, the elemental compositions of several peat-forming plants, and the results of the elemental analyses of bog samples, were examined by the SIMCA method. A clear difference was found between fens and raised bogs. Factor analysis of the elemental compositions shows that the concentrations of most of the elements reflect their natural abundance in the surrounding region. Some concentrations are influenced by anthropogenic pollution, e.g. lead, and by plant metabolism. The cluster analysis together with the training sets shows the degree of the deposition of mineral material from adjacent rivers and the type of plant growth which formed the peat.     

Variability of 40K isotopic composition in forest soils under different environmental conditions

Radiopotassium isotopic composition (⁴⁰K/K, %) of several forest soils did not show a constant value of generally known 1.17 × 10^?2 %, but they were varied significantly from 0.4 × 10^?2 to 1.3 × 10^?2 % at different locations under different environmental conditions. Surface portion of a soil (2–4 cm in depth) gave always lower ⁴⁰K/K values compared with those of deeper soil layer (35–40 cm in depth). Ion exchange of K⁺ with NH₄ ⁺ did not affects the ⁴⁰K/K value in any soils, which revealed with chemical leaching experiments in the laboratory. Some plant species showed much lower ⁴⁰K/K values than those in the surface soil. Possible reasons for varying ⁴⁰K/K values obtained in this study may result from a dynamic behavior of potassium in soil, probably due to biological activity including root uptake and decomposing soil organic matter by microorganisms in the forest floor.     

Elemental composition of Nigerian harmattan dust

Six samples of harmattan dust collected over three seasons of harmattan in Nigeria were analyzed for 29 elements by instrumental neutron activation analysis. The mean concentrations are (in g/g): Al, 61100; As, 6.59; Au, 0.16; Ba, 695; Br, 195; Ce, 122; Cl, 6200; Co, 20.9; Cr, 119; Cs, 2.72; Eu, 1.31; Fe, 43 1000; Ga, 21.9; Hf, 8.05; K, 15700; La, 53.9; Mg, 8700; Mn, 825; Na, 6400; Rb, 82.4; Sb, 32.7; Sc, 10.3; Se, 6.61; Sm, 6.50; Th, 14.0; Ti, 4900; U, 6.28; V, 81.6; Zn, 2200. The results are compared to similar recent studies in the German Democratic Republic.     

Effect of bombardment with helium ions on the molecular-topological structure and elemental composition of the surface of Kynar polyvinylidene fluoride resin

A polyvinylidene fluoride film has been bombarded with accelerated (1–5 MeV) helium ions at a fluence of 10¹⁵ ion/cm². Unlike the completely amorphous structure of the unirradiated polymer, the weight fraction of the crystalline modification in the irradiated polymer is 0.86–0.90, which is indicative of the efficient conversion of the amorphous structures of the polymer pseudo-network into the crystalline ones. Irradiation with 1-MeV ions leads to the greatest changes in the fraction of the crystalline modification and the glass-transition and flow temperatures of the polymer. The detachment of fluorine and the surface carbonization of the irradiated polymer occur under the ion beam.     

Effect of growth conditions on the rheological properties and chemical composition ofVolcaniella eurihalina exopolysaccharide

The exopolysaccharide produced byVolcaniella eurihalina, an halophilic eubacterium, under different environmental and nutritional conditions, is studied.V. eurihalina synthesizes an acidic heteropolysaccharide, composed by rhamnose, glucose, and mannose, as well as amino sugars, uronic acids, and acetyl and sulphate residues. This composition varies depending on the nutrients of culture medium. Viscosity and pseudoplasticity of the polymer solutions are also influenced by the nutritional conditions in which the microorganism was grown.     

Effect of thermal treatment conditions on the phase composition and structural characteristics of V-Mo-Nb-O catalysts

The formation of an active phase in V-Mo-Nb oxide catalysts for the selective oxidation and ammoxidation of ethane during thermal treatment in air and in helium was studied using high-temperature in situ and ex situ X-ray diffraction analysis, transmission electron microscopy, IR spectroscopy, and the differential dissolution method. It was found that, in thermal treatment below 500°C, the formation occurred through the same irreversible steps with the formation of a unidimensionally ordered layered compound with structure elements like Mo₅O₁₄ regardless of the calcination atmosphere. Above 500°C, the formation of crystalline phases took place; the composition and structure of these phases depended on the atmosphere of thermal treatment. The unidimensionally ordered V-Nb-Mo oxide with structure elements like Mo₅O₁₄ exhibited the best catalytic properties.