Applications of aquatic and sediment toxicity testing in situ

Bioassays using caged fish, bivalves, and other macroinvertebrates (in situ toxicity tests) supplement traditional eco-toxicological approaches such a s laboratory toxicity tests and evaluation of benthic invertebrate or fish communities. In situ toxicity tests incorporate complex site-specific condi tions (e.g., suspended solids, light, dissolved oxygen, pH, salinity, and t emperature), which may alter contaminant toxicity and/or bioavailablity. Fi sh and bivalves have been used most frequently due to technology transfer f rom aquaculture methodologies and other concerns about these animal groups. More recently, laboratory methods for testing commonly used macroinvertebr ates (e.g., cladocerans, amphipods, and midges) have been developed for use in the field. A concise summary of the uses and applications of in situ te sting (e.g., stressor identification, chronic bioaccumulation studies, stor mwater runoff assessment, evaluation of photoinduced toxicity at PAH-contam inated sites, and assessment of episodic acidification of streams) is provi ded.