Schadstoffbelastung durch Persorption von Bodenpartikeln

The term persorption describes the paracellular uptake of particles from the digestive tract. It has been shown that solid, hard microparticles such as starch granules, cellulose particles, fibres and crystals are incorporated from the digestive tract. It is likely that an uptake of soil contaminants may also occur via this mechanism, thereby increasing the health risks of children through soil ingestion. The aim of this study was to evaluate the significance of such soil contaminant absorption via this mechanism using data from the literature. Since no information was available on the persorption of soil particles, studies using other models had to be evaluated. The results of these studies show that a persorption of soil particles must be expected. The maximum persorption rate occurs for diameters of <35 μm which is in the range of diameters of street dust, clay and coarse clay. The persorption of these particles is therefore of significance. Data from the literature, however, does not allow an estimation of the magnitude of persorption of such soil particles. Basically, it is conceivable that a relevant ingestion of less mobile pollutants is possible through their persorption in the gastrointestinal tract. Aside from an increased internal exposure via the persorption of soil particles carrying contaminants, additional health risks may occur through the long-term deposit of such particles, the presence of potential allergens as well as through the embolisation of small vessels.     

Stadtklima

Zusammenfassung  Teil 2 dieses übersichtsartikels zur Stadtklimatologie besch?ftigt sich mit der Auspr?gung ausgew?hlter Klimaelemente in urbanen R?umen, der lufthygienischen Problematik in St?dten sowie mit den human-biometeorologischen Aspekten der Stadtklimatologie. Es wird zun?chst der Aufbau der Stadtatmosph?re und die st?dtische Strahlungs- und W?rmebilanz dargestellt. Anschlie?end werden der urbane W?rmeinseleffekt, das bodennahe Windfeld, die urbanen Luftfeuchtigkeitsverh?ltnisse und die Luftqualit?t exemplarisch erl?utert. Planerische M?glichkeiten zur Verbesserung des Klimas in unseren St?dten werden vorgestellt und ihre Wirksamkeit abgesch?tzt. Zum Abschluss wird die Rolle des Stadtklimas innerhalb der aktuellen Diskussion rund um die Problematik der globalen Klimaentwicklung beleuchtet und anhand der Ergebnisse bisheriger Untersuchungen positioniert. OnlineFirst: 04. August 2004     

Bestimmung der resorptionsverfügbaren PCDD/PCDF aus Kieselrot

For the estimation of intestinal absorption of polychlorianted dibenzodioxins/dibenzofurans (PCDD/F), ain-vitro model was developed in order to study PCDD/F mobilization by digestion of technogenic soils using ?Kieselrot” (red slag) as substrate and digestive juice model mixtures. Red slag samples were shaken successively with model mixtures of saliva, gastric juice, duodenal juice and bile. The solids were separated, the aqueous phase was extracted with hexane, the hexane extract analyzed for PCDD/F. Additionally, the PCDD/F-content of the red slag was determined. Extraction efficiency was tested with three different digestive juice model mixtures and also tap water for comparision. The percentage of PCDD/F transferred from the red slag sample into the digestive juice mixture was defined as absorption availability. In our experiments, a maximum absorption availability of 2 % was found.