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R9 Laboratory SOP 1034
7-DAY SEDIMENT TOXICITY TEST METHOD USING }{\b\i\f2\fs24 Hyalella azteca
Summary
This SOP describes procedures for testing the short-term adverse effects of potentially contaminated sediment on freshwater amphipods, Hyalella azteca, during static- renewal 7-day exposures. This method has been written following the method outlined in the Environmental Monitoring and Assessment Program manual, 1994 Pilot Laboratory Methods Manual for Streams, EPA/620/R-94/003.
This procedures is applicable to sediments containing most chemicals, either individually or in formulations, commercial products, and known or unknown mixtures.
The relative toxicity of freshwater sediments can be determined through a 7-day static-renewal test with solid phase sediment and overlying water in 175 mL glass or plastic chambers. Mortality and sublethal effects such as length and weight are determined after exposure of a specific number (usually 20) of amphipods to a quantity of test sediment. Response of amphipods to the test sediment is compared with response in control sediment. A negative control or reference sediment is used to provide (a) a measure of the acceptability of the test by providing evidence of the health and relative quality of the test organisms, and the suitability of the overlying water, test conditions and handling procedures, etc., and (b) the basis for interpreting data obtained from the test sediments.
The toxicity of field collected sediment is indicated by the percent mortality of amphipods exposed to that sediment compared to those exposed to control sediment.