Erprobung und Erfolgskontrolle eines Phytoremediations-verfahrens zur Sanierung Sprengstoff-kontaminierter B?den

Zusammenfassung  Die Befunde des in seiner Konzeption in Teil I dargestellten Freilandexperimentes dokumentieren die TNT-Abreicherung und Erholung des Standortes im Laufe der Phytoremediation. Das Monitoring umfasst Erhebungen im Feld (Nitroaromatengehalte in Boden, Sickerwasser und Pflanzen; Erfassung von Bodenorganismen und Streuabbau) und den Einsatz einer Biotestbatterie mit 6 Einzeltests. Die Daten belegen die hohe Heterogenit?t der TNT-Kontamination, eine rasche initiale Abreicherung und eine geringe Verlagerung von Nitroaromaten in Pflanzen und Sickerwasser. Die anf?nglich rasche Transformation des TNT zu Aminodinitrotoluolen l?sst nach 3 Monaten deutlich nach. Mit Hilfe der Biotestbatterie wird die Toxizit?t des Bodens differenziert beurteilbar; die boden-biologischen Befunde lassen Langzeitwirkungen der TNT-Belastung wahrscheinlich werden. Eine Gesamtbeurteilung des Projekts wird im dritten Teil der Artikelserie erfolgen. OnlineFirst: 10. 09. 2001     

Trace elements in buried human bones: intra-population variability of Sr/Ca and Ba/Ca ratios – diet or diagenesis?

A comparative analysis of trace element data of human skeletal material from four archaeological sites is presented. We show that the state of histomorphological preservation of bone, which is a measurement for the degree of its diagenetic alteration, closely corresponds to the Sr/Ca and Ba/Ca ratios at an intra-population level. This study challenges the validity of dietary studies that are based on the presently used procedures for sample preparation and subsequent evaluation of strontium and barium concentrations.     

Miniaturization,genome size and the origin of functional constraints in the visual system of salamanders

During their evolution, many species of lungless salamanders (fam. Plethodontidae) have experienced a great increase in genome size and consequently in the size of their cells, including sensory receptors and neurons. In addition, some have become extremely miniaturized. The consequences of these events and the morphological compensatory processes are studied in the visual system of juvenile and adult salamanders.     

Multidimensional risk analysis of antifouling biocides

In order to improve the orientation about the long-term sustainability of the use of the antifouling biocides tributyltin (TBT), copper, Irgarol® 1051, Sea-Nine? 211 and zinc pyrithione, used for the protection of fouling in sea-going ships, the risks posed to the marine biosphere due to their use are evaluated. The newly presented method of risk analysis uses release rate, spatiotemporal range, bioaccumulation, bioactivity and uncertainty as 5 dimensions of ecotoxicological risk. For each dimension, a scoring procedure is briefly described. The resulting risk profiles of the antifouling biocides show characteristics of the different substances, but also indicate where further information is required. Application of the method is proposed as a decision support in the integrated development of products, informed purchasing and for regulatory purposes.     

Suitability of using diffusive gradients in thin films (DGT) to study metal bioavailability in mine tailings: possibilities and constraints

Background, aim, and scope  

Diffusive gradients in thin films (DGT) have been recognized as a suitable tool to assess in situ metal bioavailability in soils. Mine tailings have some singular characteristics such as high heavy-metal concentrations, low pH, or absence of water retention capacity that may compromise the correct application of this technique whose applicability is known to be pH dependent. The goal of this study was to determine the response of DGT devices in heavy-metal-polluted mine tailings with different pH. In addition some experiments were performed in order to determine the effect of acidic pH and dissolved ions on the binding properties of the chelating resin.     

Influence of the initial state of carbon nanotubes on their colloidal stability under natural conditions

The colloidal stability of dry and suspended carbon nanotubes (CNTs) in the presence of amphiphilic compounds (i.e. natural organic matter or surfactants) at environmentally realistic concentrations was investigated over several days. The suspensions were analyzed for CNT concentration (UV-vis spectroscopy), particle size (nanoparticle tracking analysis), and CNT length and dispersion quality (TEM). When added in dry form, around 1% of the added CNTs remained suspended. Pre-dispersion in organic solvent or anionic detergent stabilized up to 65% of the added CNTs after 20 days of mild shaking and 5 days of settling. The initial state of the CNTs (dry vs. suspended) and the medium composition hence are critical determinants for the partitioning of CNTs between sediment and the water column. TEM analysis revealed that single suspended CNTs were present in all suspensions and that shaking and settling resulted in a fractionation of the CNTs with shorter CNTs remaining predominantly in suspension.