International Journal of PIXE

The change of shape and elemental concentration of cellular samples in In-Air micro PIXE analysis was investigated. Cultured bovine aortic endothelial cells were analyzed in the atmosphere by using 2.6 MeV proton micro-beams. The shape of cross-sections of cells was not so much distorted by beam irradiation and the concentrations of trace elements did not change too, except for S. The concentration of S changed with strongly depending on the temperature rise due to beam irradiation.

The method to observe the localization of the trace elements in cultured human cell, by the micro Particle Induced X-ray Emission (PIXE) camera, was developed.

The analyzed samples received the eosin staining, which colored the nucleus of cell violet. The scanned areas of the sample with particle irradiation were colored brown by the heat during irradiation. The brown scanned areas were examined by an optical microscope at 400 X magnification and photographed. Then the photo was digitized and loaded into the microcomputer. By microcomputer, the photo of the scanned area was superimposed onto the image of the micro PIXE camera, by matching the scanned area to the image of micro PIXE camera.

This superimposed image enabled us to determine whether the elements exists in cytosol, or in nucleus.

The study of trace elements level in coal arouses much interest in recent days to assess and evaluate the environmental impact related to its benefit and usage in applying it to the problem of mining site. Further, it is more important during the coal combustion in thermal power stations particularly in relation to the emission of air toxic, disposal and utilization of fly ash. The paper describes the level of nineteen environmentally significant trace elements found in recently discovered Permian Gondwana coals in Barapukuria and Khalaspir of Northwestern Bangladesh using Proton Induced X-ray Emission (PIXE) spectroscopy. Both the mineral species and trace elements are expected to be due to sedimentary and aerobic environmental condition where the Permian coals have been generated depending on their degree of evolution.

Precambrian ferromanganese oxide deposits of India and Brazil were formed in optimum favorable geological situations at specific period of evolution. Two representative ferromanganese oxide ore samples have been collected from different mines of Precambrian Bonai-Keonjhar belt, Eastern India, and were irradiated with 3 MeV proton beam from a 3 MV pelletron accelerator at Institute of Physics, Bhubaneswar, India. The spectral data were analyzed by using GUPIX software package. About 20 major, minor and trace elements including Ca, Ti, V, Cr, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Zr, Mo and Pb were quantified in these ores. The obtained Mn/Fe ratio and the content of the trace elements were used in interpreting the initial formation environment of the depositional basin.

In Cambodia, artisanal mining has recently come to a social concern because of the possibility to cause environmental degradation and human health problems. The General Department of Mineral Resources of Cambodia is collecting environmental specimens in mining sites to watch the situation. This time, four water samples from Sampov Loon and one from Memong mining site were sent from the Department to Hiroshima University, Japan, and the samples were analyzed by means of PIXE at the University. A volume of 10 μl from each sample was separated and dropped onto 4 μm polypropylene backing foil. The measurement was carried out by using 2.5 MV single-ended Van de Graaff accelerator. A Si(Li) detector (active area, 80mm²; sensitive depth, 5mm; Be-window's thickness, 25 μm; resolution, 167 eV fwhm at 5.9 keV) was used for both of in vacuo PIXE and non-vacuum external beam PIXE measurement. A computer code PIXS was used for the quantification. The result indicates that there are at least two kinds of water in Sampov Loon and one of them possibly represents polluted condition.

The samples of common salts available in Japan and Mongolia were analyzed for the presence of heavy elements by PIXE spectrometry using 2.5 MeV proton beam at the Tokyo Institute of Technology Van de Graaff Laboratory. The samples were dissolved in water and insoluble and soluble fractions were determined separately. The soluble constituents were treated with pre-concentration method by using DBDTC to form the complexes appropriate to percolation through a Nuclepore Track - etch Membrane. Insoluble particles were precipitated on the filter surface for subsequent direct irradiation. Combined As and Pb concentrations in insoluble portion of salts were found in the range of 7.2 – 102 ppm based on mass analysis of insoluble materials collected on Nuclepore Track - etch Membrane of the pore diameter 0.4μm. This level of toxic heavy metals makes a caution from the view-point of their safe intake.

In recent years, the number of artisanal gold miners in Mongolia is drastically increasing. They use mercury to extract gold from ore and release it to the environment and this fact has been an issue of concern in the nation. In order to monitor the degree of exposure to mercury, artisanal miners' hairs from a typical mining site, Boroo, were analyzed by PIXE at Nishina Memorial Cyclotron Center, Japan. The result indicated that mercury content in the hairs is very low in spite of the miners' practice to work in mercury fume for smelting. However the result showed high level of arsenic, up to 3.2 ppm, although miners' do not use arsenic in the smelting process.

Coins are important archaeological objects that can provide useful information regarding preparation methodology and provenance. Their classification plays a fundamental role in dating historical events, in constructing trade routes and in establishing the welfare of population. Several Indian copper coins of different periods have been studied using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopic technique. The method is rapid, efficient, multi elemental and non-destructive in nature. Concentrations of the major and trace elements like Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Pb have been estimated in these copper coins. In the present investigation, an attempt has been made to characterize some Indian copper coins of different periods using EDXRF technique.

Proton Induced X-ray Emission Technique (PIXE) has been used in analyzing Gold standards of 22, 20, 18, and 14 karats with a proton beam of Energy 3.3 MeV at the newly commissioned Folded Tandem Ion Accelerator (FOTIA) at B.A.R.C, Trombay. Well resolved Au and Ag X-rays were detected at a current of 3 nA. Percentage values of gold and silver were calculated and were checked with those obtained by Energy Dispersive X-ray Fluorescence (EDXRF) Method and were found to be in agreement with the certified values as well as those obtained by XRF.

Samples of fine airborne particulate matter (PM_2.0) have been collected at three sites located in the Mexico City Metropolitan Area (MCMA) during July, August, and September 2000. The elemental concentrations of these samples were determined by PIXE so that twelve elements (S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br and Pb) were consistently detected. These results produced a database, which was statistically analysed; first by Principal Components so to identify the pollution sources, and, subsequently, by Absolute Principal Component Scores analysis in order to estimate the corresponding source apportionment contributions. Other elements such as V and Cr were also detected in around 20% of the samples and, therefore, they were not considered statistically significant. Thus, these elements, as well as some others found only occasionally and in the trace range, were left out of the discussion. All calculations were performed using a standard statistical package following the method developed by Thurston and Spengler. Four main pollution sources were identified and the source apportionments were found in good agreement with other estimations found in the literature. The results were obtained individually for the three sampling sites, but the complete results are presented for just one of the sites in order to simplify this presentation.