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R9 Laboratory SOP 1002
SEA URCHIN (Strongylocentrotus purpuratus) and SAND DOLLAR (Dendraster excentricus) LARVAL DEVELOPMENT TOXICITY TEST
Summary
The procedure describes the storage, handling, preparation, and toxicity testing of the pore water phase of sediment samples, effluent samples, and ambient water samples.
This method estimates the chronic toxicity of environmental samples (e.g. effluents, receiving waters) to the developing embryos of the echinoderms sea urchins (Strongylocentrotus purpuratus) or sand dollars (Dendraster excentricus).
The purpose of the test is to determine the concentrations of a test substance that reduce development during a 72-hour exposure of developing echinoderm embryos. Concentrations of materials adversely affecting embryo development under the conditions of this test are usually acutely and chronically toxic to one or more of several common marine test species and, by extension, are presumably acutely and chronically toxic to other of the many untested marine species.
The procedure follows methods specified in Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to West Coast Marine and Estuarine Organisms, EPA/600/R-95/136 (USEPA, 1995) and in Methods for Assessing the Toxicity of Sediment- Associated Contaminants with Estuarine and Marine Amphipods, EPA/600/R-94/025 (USEPA, 1994) for pore water samples. U.S. EPA Region 9 Laboratory staff perform toxicity tests on samples from NPDES facilities or Superfund sites.
This method measures the toxicity of a sample to early development of sea urchins or sand dollars by exposing fertilized eggs to samples and allowing development for 72 hours. The test is terminated by the addition of a preservative and the percent normal development is determined by microscopic examination of 100 larvae in an aliquot from each treatment. The test endpoint is normal pluteus larval development. Point estimates and hypothesis-derived endpoints are calculated using the TOXIS computer program to determine the samples in which larval development is reduced or statistically significantly different from the control. A reference toxicant test is conducted with copper sulfate.