Abstract: In air particulate matter, sampled at a suburban site near the city of Antwerp, Belgium, more than 1500 individual Pb-containing aerosol particles with projected diameters between 0.2 and 15 μm were analyzed by automated electron probe X-ray micro analysis (EPXMA) for 26 elements and morphological features. Laser microprobe mass analysis (LAMMA) was used to detect elements with Z < 11, particularly ammonium compounds. The Pb-containing particles were classified into five main classes: Pb-sulfates, Pb-halides, soil related Pb, Pb associated with medium atomic number elements and Pb associated with high atomic number elements. Each class was divided into several distinct particle types, of which the abundance (in number and mass %), the mean projected particle diameter, and the chemical composition were determined. Auto exhaust products are responsible for Pb-sulfates and Pb-halides, making up respectively 66.7 and 27.8% by mass of the Pb-containing particles. Ammonium sulfate coatings were found to be present on nearly all Pb particles. The observations were correlated with daily concentrations of Pb and Br, obtained by particle induced X-ray emission analysis (PIXE).

Abstract: Trace elements can influence dental health, possibly by altering tooth resistance during preeruptive development. Therefore, it was investigated whether lead and fluoride would be incorporated into the calcifying matrices or the cellular parts of tooth germs in vitro. Using laser microprobe mass analysis, the localization of lead and fluoride was studied in the different layers or tooth germs that had been cultured in a medium to which PbCl2 of NaF had been added in different concentrations. Both elements could only be detected in the dentine layer. Hence, the enamel organ in the secretory stage of tooth development excludes lead and fluoride from the enamel, even when enamel formation by the ameloblasts is visibly disturbed. Furthermore, there seemed to be a process of saturation in the accumulation of lead and fluoride in the dentine.

Abstract: Through a combined use of light- and electron microscopy with microanalytical techniques, the aluminium distribution in gills of aluminium-exposed catfish was investigated. This study demonstrates that also with the ''acid-resistant'' catfish, exposed during seven days to acidified water (pH=4.3) with an elevated aluminium concentration (1 mg Al/l), aluminium can be found at, and even in, the gills.