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(30-01) Pitfalls of toxicity reduction evaluation based on biotests for contaminated groundwater. Küster, Eberhard*,1, Dorusch, Falk1, Weiss, Holger1, Altenburger, Rolf1, 1 UFZ Centre for Environmental Research Leipzig-Halle, Leipzig, Germany ABSTRACT- The city of Bitterfeld (Germany) was a centre of chlororganic chemical industry for the last century resulting in a heavily contaminated groundwater body. The research in the SAFIRA project (http://safira.pro.ufz.de/) aims to develop different new in situ groundwater remediation techniques to deal with the complex contamination. The success of these remediation techniques is controlled and supervised in two ways. Beside the regular chemical analysis of some 20 organic and anorganic chemicals, the groundwater is biotested. Discontinously, green algae, daphnia, fish embryos and bacteria are used to monitor phytotoxicity, acute/chronic toxicity, developmental toxicity and genotoxic effects. Continously, effects on energy metabolism of luminescent bacteria (Vibrio fischeri) are monitored with an on line biomonitor. The major challenge is to differenciate between different causes of toxicity such as groundwater contamination, milieu factors or sample manipulations evoked by remediation techniques. Examples are possible toxic effects being correlated to certain salts, ions, H2S but also chlororganics and their metabolites or to malfunction or maloperation of remediation machinery, misuse or misdosage of auxiliary substances and the unknown synthesis of toxic metabolites in the remediation reactors. Experiences made at a field station used for toxicity reduction evaluation (TRE) of groundwater remediation techniques will be illustrated. Problems, difficulties and drawbacks focusing on the use of luminescent bacteria for on-line biomonitoring will be discussed. Key words: groundwater, toxicity reduction evaluation, on-line biomonitor, vibrio fischeri |
