TOXICITY AND BIOACCUMULATION OF SEDIMENT-ASSOCIATED CONTAMINANTS USING FRESH-WATER INVERTEBRATES - A REVIEW OF METHODS AND APPLICATIONS

This paper reviews recent developments in methods for evaluating the t oxicity and bioaccumulation of contaminants associated with freshwater sediments and summarizes example case studies demonstrating the appli cation of these methods. Over the past decade, research has emphasized development of more specific testing procedures for conducting 10-d t oxicity tests with the amphipod Hyaella azteca and the midge Chironomu s tentans. Toxicity endpoints measured in these tests are survival for H. azteca and survival and growth for C. tentans. Guidance has also b een developed for conducting 28-d bioaccumulation tests with the oligo chaete Lumbriculus variegatus, including determination of bioaccumulat ion kinetics for different compound classes. These methods have been a pplied to a variety of sediments to address issues ranging from site a ssessments to bioavailability of organic and inorganic contaminants us ing field-collected and laboratory-spiked samples. Survival and growth of controls routinely meet or exceed test acceptability criteria. Res ults of laboratory bioaccumulation studies with L. variegatus have bee n confirmed with comparisons to residues (PCBs, PAHs, DDT) present fro m synoptically collected field populations of oligochaetes. Additional method development is currently underway to develop chronic toxicity tests and to provide additional data-confirming responses observed in laboratory sediment tests with natural benthic populations.