Abstract: Yamuna River sediments are more enriched in metals than those of the Ganges and average Indian river sediments. Variation of metals in suspended, bed and core sediment are due to the varying proportions of grain size and mineral content. Iron, Mn and Pb show a preference for the oxide fraction, whereas Cu and Zn are predominant in organic and carbonate fractions of sediments. Of the total elemental content, 80% Mn, 78% Fe, 69% Pb, 67% Cu and 55% Zn are available in chemically mobile phases of the sediments. The high partition coefficient of metals with respect to Mn suggests similar chemical mobility and preferences for solid phases. River sediments in the vicinity of Delhi show an increase in sorption of metals downstream, consequently metals are retained in sediments. The high correlation coefficient and significant regression relation among the metals indicate their similar behaviour during transport. At Allahabad, the contribution of the Yamuna to the Ganges is 3200 t Pb year−1, 12 100 t Zn year−1 and 8500 t Cu year−1 in particulate form.

Abstract: The methodology of direct hair analysis by energy-dispersive x-ray fluorescence was studied. The effect on the XRF result of having a non-homogeneous radial distribution of the analyte in a single hair strand and the macroscopic effects in a bundle of hairs were calculated to evaluate possible systematic errors. The detection limits were mapped as a function of the target thickness and surface fraction. It appeared that a 10 mg cm−2 sample thickness, i. e. a target with about four layers of hair strands, is recommended. The standard deviation of this simple direct analytical method is 619% for some important elements. Discrepancies with neutron activation analysis had a mean value of around 15%. About twelve elements can be determined simultaneously on a routine basis.

Abstract: Soils are complex mixtures of organic, inorganic materials, and metal compounds from anthropogenic sources. In order to identify the pollution sources, their magnitude and development, several X-ray analytical methods were applied in this study. The concentrations of 16 elements were determined in all the soil samples using energy dispersive X-ray fluorescence spectrometry. Soils of unknown origin were observed by scanning electron microscopy equipped with a Si(Li) X-ray detector using Monte Carlo simulation approach. The mineralogical analyses were carried out using X-ray diffraction spectrometry. Due to the correlations between heavy metals and oxide compounds, the samples were analyzed also by electron probe microanalyzer (EPMA) in order to have information about their oxide contents. On the other hand, soil pH and salinity levels were identified owing to their influence between heavy metal and soil-surface chemistry. Moreover, the geoaccumulation index (I geo) enables the assessment of contamination by comparing current and pre-industrial concentrations.

Abstract: The assessment of damage to indoor cultural heritage, in particular by pollutants, is nowadays a major and growing concern for curators and conservators. Nevertheless, although many museums have been widely investigated in Europe, the effects of particulate matter and gaseous pollutants in museums under tropical and subtropical climates and with different economic realities are still unclear. An important portion of the world's cultural heritage is currently in tropical countries where both human and financial resources for preserving museum collections are limited. Hence, our aim is to assess the damage that can be caused to the artwork by pollution in hot and humid environments, where air quality and microclimatic condition differences can cause deterioration. As a case study, particulate matter as well as gases were collected at the Oscar Niemeyer Museum (MON) in Curitiba, Brazil, where large modern and contemporary works of art are displayed. NO2, SO2, O3, Acetic Acid, Formic Acids and BTEX, in the ambient air, were sampled by means of passive diffusive sampling and their concentrations were determined by IC or GCMS. The particulate matter was collected in bulk form and analyzed with the use of energy dispersive X-ray fluorescence and aethalometer. The chemical compositions of individual particles were quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis. The gaseous and particulate matter levels were then compared with the concentrations obtained for the same pollutants in other museums, located in places with different climates, and with some reference values provided by international cultural heritage conservation centers. Results are interpreted separately and as a whole with the specific aim of identifying compounds that could contribute to the chemical reactions taking place on the surfaces of artifacts and which could potentially cause irreversible damage to the artworks.

Abstract: The energy distributions of ions produced in a spark source mass spectrometer were recorded for different trace element ions and for the total ion current. Both electrodes of pure doped graphite, and with 10% potassium salts added, were examined. The results show that the measured energy of an ion is mainly determined by the m/z ratio and that the energy of the total ion current depends on the sample composition. It was also clear that if the accelerating voltage is set to obtain maximum transmission of the total ion current, the fraction of the heavy elements that is discriminated at the β-slit depends on the matrix composition if the pass band of the instrument is narrow. These effects influence considerably the accuracy in the analysis of variable samples.

Abstract: Expressions are presented for calculating the matrix effect and the pure particle size effect in the XRF analysis of particulate samples with a discrete particle size. The equations are based on the absorption-weighted radiometric diameter concept. Two excitationdetection geometries are considered, with the angles between the sample plane and both the incident and emerging radiation being either 90° (π geometry) or 45° (π/2 geometry). Calculations were made for different sample loadings and exciting radiation energies. The influence of these parameters on the matrix and pure particle size effects is shown. From the results, it is possible to predict the performances of alternative experimental correction procedures for the particle size effect, involving dual measurements at different excitation energies or in different excitationdetection geometries.

Abstract: Individual aerosol particles from the remote marine atmosphere were investigated by scanning electron microscopy and electron microprobe analysis. A large fraction of the silicate mineral component of the aerosol was found to be internally mixed with sea-salt aerosol particles. This observation explains the unexpected similarity in the size distributions of silicates and sea salt that has been observed in remote marine aerosols. Reentrainment of dust particles previously deposited onto the sea surface and collision between aerosol particles can be excluded as possible source mechanisms for these internally mixed aerosols. The internal mixing could be produced by processes within clouds, including droplet coalescence. Cloud processes may also be responsible for the observed enrichment of excess (nonsea-salt) sulfate on sea-salt particles.

Abstract: Artificially generated NaCl particles were coated with PAH's by using a condensation technique. These particles were exposed to reactive gases like ozone, bromine and nitrogen dioxide. The original as well as the exposed particles were investigated by fluorimetric analysis and by LAMMA (Laser Microprobe Mass Analysis) in the desorption mode, which allows the evaporation and characterization of surfaces of single particles. The results are interpreted in terms of possible heterogeneous atmospheric reactions. The reactivity of the considered PAH's towards nitrogen dioxide was found to be negligible. The structure of the reaction products formed with ozone was partially elucidated.