Selection of Bioassays for Sediment Toxicity Screening

Abstract :A large monitoring study of 80 freshwater sediments, using the TRIAD approach, was conducted in Flanders, Belgium using a battery of microbiotests and conventional assays. The test battery covered several phylogenenic groups and included acute or short-term chronic tests on the sediments’ porewater with bacteria (Vibrio fischeri), algae (Raphidocelis subcapitata), crustaceans (Thamnocephalus platyurus andDaphnia magna) and fish (Clarias gariepinus). Whole sediment tests withHyalella azteca andChironomus riparius were conducted concurrently. Uni- and multivariate statistical techniques were used to determine the discriminatory power, the toxicity detection capacity and the redundancy of the different assays. A battery composed of a minimal set of porewater and whole sediment assays is proposed for the initial toxicity screening of contaminated sediments.