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2K - Sediment Assays (TU18/15) New emerging effect-related sediment parameters: a case study of Freshwater and Estuarine Sediments. Hansen, Peter-Diedrich1, Unruh, Eckehardt2, Fischer, Birgit3, 1 University Professor, Departmental Director, Berlin, Berlin, Germany2 Senior Scientist, Berlin, Berlin, Germany3 engineer, Berlin, Berlin, Germany ABSTRACT- Beside the sediment quality objective approach using the NOEC (No Observed Effect Concentration) approach of the most sensitive sediment organisms or sediment exposed organisms and their biochemical responses (biomarker) there is a need for classification and to assess the toxicologically-effective pollution load of sediments and dredged materials (Schubert, Krebs and Bergmann 2000). For the selection of risk categories or asssessing sediment quality for the management of sediments and dredged materials an assessment system was developed at the German Federal Institute of Hydrology (BFG) and is currently in testing. The assessment by pT-values (pT=potentia toxicologiae=toxicological exponent) is an ecotoxicological classification for sediments. The pT-value is the negative binary logarithm of the first non-toxic dilution factor in a dilution series in geometric sequence with a dilution factor of two. The endpoints shows in the form of an index (pT-value) how many times a sample must be diluted in the ratio 1:2 to reach the stage of non toxic. Concerning the handling of dredged materials the toxicity classes defined by the pT-value method are categorized in three levels unproblematic, critical and hazardous (Krebs, 1999, 2000, 2001). The advantage of the pT-values is the comparability (numerical designation) of different endpoints and methods for better interpretation of the effects. Several case studies with freshwater sediments and estuarine sediments will demonstrate examples of exocotoxicological evaluation of sediments e.g. by the pT-value. Key words: Immunotoxicity, sediments, Genotoxicity, Endocrine Effects |
