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R9 Laboratory SOP 1003
SEDIMENT OR PORE WATER TOXICITY TESTS USING MARINE AND ESTUARINE AMPHIPODS
Summary
The procedures describe the storage, handling, preparation, and toxicity testing of the solid phase or pore water phase of sediment samples. A 10-day static acute toxicity test is conducted with one of the following marine or estuarine amphipods: Ampelisca, Rhepoxinius, Leptocheirus or Eohaustorius.
The purpose of the whole sediment test is to determine the toxicity of marine sediments to amphipods by comparing their survival in test sediments to that in native control or reference sediments. Test results are reported as the number of sediment treatments in which amphipod mortality is statistically significantly different from either native controls or reference sediment treatments. An additional endpoint that can be used is reburial of surviving amphipods.
The purpose of the pore water toxicity test is to determine the toxicity of sediment pore water to amphipods by comparing their survival in pore water to that in control seawater of the same salinity. Test results are reported as the number of pore water treatments in which amphipod mortality is statistically significantly different from the controls.
The procedures follow methods specified in Methods for Assessing the Toxicity of Sediment- Associated Contaminants with Estuarine and Marine Amphipods, EPA/600/R-94/025 (USEPA, 1994). U.S. EPA Region 9 Laboratory staff perform toxicity tests on sediment and pore water samples from ocean dumping or Superfund sites.
This method describes testing marine and estuarine amphipod crustaceans in the laboratory to evaluate the toxicity of contaminants associated with whole sediments or sediment pore water. Reference, control, and test sediment are sieved (if necessary) and composited in preparation for the test. Sediment samples are prepared by placing one hundred seventy-five milliliters or 2 cm of sediment in a 1 L beaker with 800 mL overlying seawater. Pore water samples are centrifuged for 30 minutes at 2,500 x g, and 100 mL of pore water is added to a beaker. Twenty amphipods in each of a minimum of four replicates are exposed to each whole sediment sample for 10 days. Ten amphipods in each of a minimum of four replicates are exposed to each pore water sample for 4-10 days. Pairwise comparisons are conducted to determine the samples in which amphipod mortality is statistically significantly different from the control. A parallel positive control test is conducted with cadmium chloride.