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2Q - Online Biomonitoring (WEP/164) Online biomonitoring of sediment toxicity with the Multispecies Freshwater Biomonitor. Gerhardt, A.1, 1 LimCo International, Ibbenbueren, Germany ABSTRACT- The Multispecies Freshwater Biomonitor (MFB) has been used for about a decade as online biotest and biomonitor in aquatic ecotoxicology, waste water and drinking water control with a variety of test species, such as different crustaceans, fish and insects. Sediment toxicity tests performed with whole sediments in the laboratory and in situ receive increasing importance, however, until now, no automated and cost-effective, easy-use method is available to record behavioural or physiological parameters of organisms exposed in their sediment without any physical disturbance. The MFB overcomes these problems: It is based on quadropole impedance conversion technique, which does not affect the organisms normal behaviour and records quantitatively different types of activity of the organisms in their sediment. Examples are given for Hydropsyche angustipennis (Trichoptera), Caenorhabditis elegans (Nematoda), Dendrobaena veneta (Annelida) and Tubifex tubifex (Annelida): measurements of the behaviour of single individuals and groups of organisms in different types of test chambers in water are compared with measurements in sediment. Early warning responses measured as changes of the behaviour of Tubifex tubifex and Dendrobaena veneta under acid stress at pH 4 and 5 were recorded during 2-3 hrs and compared to the controls at pH 7. The suitability of the different test species in the MFB, their sensitivity and potential for online biomonitoring of sediment pollution will be discussed. Key words: sediment toxicology, online biomonitor, behaviour, acid stress |
