Entwicklung und Anwendung von Methoden zur Gefaehrdungsabschaetzung quecksilberkontaminierter Standorte

An zwei mit Quecksilber hochkontaminierten Standorten wurden Untersuchungen zum Gefaehrdungspotential durchgefuehrt. Hierzu wurden Methoden zur Bestimmung organischer Quecksilberverbindungen in Boden, Wasser und Luft entwickelt. Durch die Anwendung toxikologischer Tests konnte gezeigt werden, dass organische Quecksilberverbindungen wesentlich toxischer wirken als anorganisches Quecksilber. Neben hochtoxischem Methylquecksilber konnte im Boden unweit der Chemischen Fabrik Marktredwitz auch Ethylquecksilber nachgewiesen werden. Durch Ultrafiltrationsversuche in der Wasserphase wurde eine grosse Affinitaet des Quecksilbers zu hochmolekularen Wasserinhaltsstoffen belegt. In Laborlysimeterversuchen konnte gezeigt werden, dass die eingebrachten Organoquecksilberverbindungen fixiert und zu anorganischem und elementarem Quecksilber transformiert werden. (orig.)At two sites, highly contaminated with mercury, risk assessment was executed. Methods were developed to determine organomercury compounds in water, air and soil. Toxicity tests demonstrated the high toxicity of organomercury compounds compared to inorganic mercury. Besides highly toxic methylmercury, ethylmercury was found in soils close to a chemical plant in Marktredwitz. In ultrafiltration-experiments mercury showed great affinity to high molecular substances in water. Lysimeter-experiments proved, that organomercury compounds are adsorbed and transformed to inorganic and elemental mercury. (orig.)SIGLEAvailable from TIB Hannover: RA 3251(93/E/104) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Toxicity of organomercury compounds: Bioassay results as a basis for risk assessment

A former mercury plant, where mercury salts and organomercurials for pesticide use were produced, caused soil contamination in high concentrations. Typical organomercurial products included ethylmercury, phenylmercury, methoxyetylmercury and ethoxyethylmercury, compounds. Risk assessment of these sites must be carried out before any major clean-up processes can be planned. A sensitive speciation technique for the various organomercury species in environmental matrices is a prerequisite for toxicity investigations. In this connection, a high-performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) technique has been developed to differentiate between and determine the presence of eight organomercury compounds in environmental samples. Using this technique, methylmercury, ethylmercury and phenylmercury and some unknown organomercury species were found in soil samples collected from the sites of an old mercury products producing plant. With regard to risk assessment, it is necessary to assess the toxicity of the organomercurials. As different microbial metabolic pathways react differently to mercury and its compounds, batteries of bioassays are, therefore, useful to evaluate the toxicity of pollutants. To describe the toxicity and genotoxicity of MeHg"+, MeOEtHg"+, EtHg"+, EtOEtHg"+ and PhHg"+, p-tolymercury chloride, nitromersol and Hg"2"+ six bioassays were used: Resazurin reduction method, Spirillum volutans test, nematode toxicity assay Panagrellus redivivus, Toxi-Chromotest and SOS-Chromotest. A ranking of the toxicity of the organomercurial is shown. The SOS-Chromotest indicated genotoxicity for 5-7 organomercurials. (orig.)Also published in: Analyst (March 1995) v. 120 p. 721-724Available from TIB Hannover: RA 3251(96/E/8) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman