Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne

In the catalytic addition of water to propyne the Au(III) catalyst is not stable under non-relativistic conditions and dissociates into a Au(I) compound and Cl2. This implies that one link in the chain of events in the catalytic cycle is broken and relativity may well be seen as the reason why Au(III) compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl

Workshop on Bioaccumulation: sediment test using benthic oligochaetes

The presented report gives a description of the results of the international workshop 'Bioaccumulation: Sediment test using benthic oligochaetes', held at Hochheim/Main, Germany, on April 26-27 1999. Scientists and experts from industry, academia and governmental agencies in the field of assessment of bioaccumulative, sediment-associated contaminants came together for a workshop held in Hochheim/Main, Germany, on April 26/27, to discuss the guideline proposal: Egeler Ph., Knacker Th., Roembke J., Schallnass H.-J., Meller M., Studinger G., Franke C. and Nagel, R. (1997). Bioaccumulation: Sediment test using benthic oligochaetes. Proposal for a draft guideline according to OECD format. 2nd, revised version. German Federal Environmental Agency (Umweltbundesamt) Berlin. Submitted to OECD, Paris, for revision. This draft guideline was based on the results of a research and development project on a standardisable method for the determination of bioaccumulation in sediment dwelling organisms (UBA-F+E 106 03 106/03; UBA Text 2/99) and conducted at ECT Oekotoxikologie GmbH, Floersheim/Main, Germany. The objective of the workshop was to review and refine methodological and scientific aspects of the proposed draft guideline. Questions concerning choice of test species, sediment ageing, duration of the test, and application of the test guideline were discussed. Furthermore, the organisation of an international ring test as well as further steps for the draft test guideline to be implemented in international guideline programs were considered. The proposed method was accepted in general. Recommendations regarding scope and application of the test, test species, and on details of test performance were given and will be included in the revised draft guideline document, which is presented in this report. (orig.)Available from TIB Hannover: RN 8908(99-125) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEUmweltbundesamt, Berlin (Germany)DEGerman

Standardisierung und Validierung eines Bioakkumulationstests mit terestrischen Oligochaeten

SIGLEAvailable from TIB Hannover: RN 8908(2000,205) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman

Umweltprobleme durch Arzneimitteln. Literaturstudie

The subject of the study was to examine whether the ecotoxicological hazard potential of pharmaceuticals or their metaboloties should be assessed. In a first step, publications on environmental problems known to be related to pharmaceuticlas were reviewed and evaluated. The data were discussed with concerned interest groups. In a second step, the data required by the 'Arzneimittelgesetz (AMG)' as part of the registration process were assessed under the aspect of suitability for ecotoxicological risk assessment. Additionally, it was evaluated which laboratory tests should be required to perform ecotoxicological risk assessments with pharmaceuticals. Preliminary risk assessments were conducted for different pharmaceutical groups if sufficient data were available. Taking into consideration the legal requirements for chemical notification within the EU, the necessity of further development of the AMG concerning ecotoxicological aspects was emphasized. (orig.)Available from TIB Hannover: RN 8422(1996,60) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman

Entwicklung und Erprobung eines Bioakkumulationstests mit endobenthischen Organismen

The presented study describes a standardised method for measuring the bioaccumulation of sediment-associated chemicals in endobenthic animals. The tubificid oligochaetes Tubifex tubifex and Limnodrilus hoffmeisteri represent the benthic infauna. Lindane and Hexachlorobenzene (HCB) were chosen as model substances. They were applied in a "1"4C-radiolabelled form. Uptake, depuration and the resulting bioaccumulation factors (BAF) were determined. The results were compared with the corresponding fish-bioconcentration factors (BCF). "1"4C-Lindane was accumulated in the tubificids by a factor of 4.7 (mean value; n=4). "1"4C-HCB reached a BAF of 6.6 (n=4) in both test species. These BAF values are based on wet weight and radioactive concentrations. Lindane was taken up faster than HCB. When transferred to clean sediment the worms eliminated both test substances rapidly and nearly completely. No major metabolites were detected in worms, sediment and water. The applied kinetic model equations fitted to the data using non-linear regression analysis showed a good fit. The determined BAF values of "1"4C-Lindane and "1"4C-HCB are orders of magnitude below the corresponding fish-BCF values. Nevertheless, the tubificid body burdens resulting from exposure to contaminated sediment can reach notably higher body burdens than fish body burdens resulting from exposure to the water phase only. The presented data show that the assessment of bioaccumulation based exclusively on the extrapolation of fish-BCF to other organisms and environmental compartments is not appropriate. A draft guideline for the determination of bioaccumulation in endobenthic animals according to OECD format (comparable to the OECD-Guideline No. 305 for testing the bioconcentration of chemicals in fish from water) is presented. (orig.)SIGLEAvailable from TIB Hannover: RN 8422(1999,2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman