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2K - Sediment Assays (TUP/139) Plant bioassays and heavy metal analysis of river sediments and sediment extracts. Halász, Gábor1, Jung, Klaus2, Heltai, György1, Percsich, Kálmán1, 1 Szent István University, Gödöllő, Hungary2 UFZ Environmental Research Centre Leipzig-Halle, Leipzig, Germany ABSTRACT- Two plant bioassays, the pollen tube growth test (PTG-test, Jung et al., UWSF - Z. Umweltchem. Okotox. 9 (6): 317-321 (1997)) and the ecotoxicological stable isotope metabolic assay (ESIMA, Jung et al., ESPR - Environ. Sci. & Pollut. Res. 6 (2): 72-76 (1999)) with garden cress (Lepidium sativum) were applied to test heavy metal contaminated sediments and sediment extracts. Sediment samples were collected from the rivers Tisza and Szamos in Eastern Hungary, which have been exposed to heavy metal pollution 2-3 years ago. A reference sample was taken from a backwater in the Tisza lake wich has no direct connection to the river. The samples were centrifuged to win pore water or lyophilized for further extraction procedure. Extracts were made in a supercritical fluid extractor using subcritical water or a mixture of water and carbon dioxide as extractants (Heltai et al., Anal. Bioanal. Chem. 373 (8): 863-866 (2002)). Heavy metal content of the sediments and their extracts was measured by ICP-AES. Cytotoxicity of the extracts and pore water samples was studied by PTG-test. Two variants of ESIMA were used to test phytotoxicity of the sediments and the extracts, wherein the total nitrogen uptake was estimated after a 14-day exposition with a sediment or a 5-hour exposition with an extract. The pore water and extract samples had similar extent of toxicity in the PTG-test and ESIMA. Tests on the direct toxicity of the sediments are still in progress. Key words: extraction, sediments, plant bioassays, heavy metals |
