An Evaluation Of The Performance Of Five Types Of Sediment Toxicity Tests

Abstract

The relative sensitivity, analytical precision, discriminatory power, concordance among end-points and concordance with sediment chemistry were compared among five sediment toxicity tests. The tests were performed with aliquots of 15 composited, homogenized sediment samples collected in San Francisco Bay and Tomales Bay, California. The end-points evaluated were: survival and avoidance of solid phase sediments by the amph ipods R h e p o x y n i u s abroriius and Anipelisca abdita; survival and abnormal development i n the embryos of the mussel Mytilus edulis exposed to elutriates; fertilization success, abnormal development, echinochrome pigment content, incidence of micronuclei, and other cytological/cytogenetic abnormalities and mitoses per embryo in the embryos of the urchin StrorigyloceNtrotus purpuratus exposed to elutriates; and survival and egg production in the polychaete Dinophilus gyrocil iatus exposed to interstitial (pore) water. Each sample was also tested for trace metal and organic compound concentration, organic carbon content, and texture. Two of the five tests (survival among M. edulis and survival among R . abroriius) were highly sensitive to the samples and had relatively high precision, but the results were correlated most highly with sedimentological variables. One of the tests (survival ainonz A. abdita) was relatively insensitive, but the METHODS Fifteen sediment samples collected in clusters of three from each of five locations in the San Francisco Bay/Tomales Bay, California area were tested. Sampling locations were selected to represent a gradient from relatively highly contaminated to minimally contaminated conditions. Each toxicity test was also performed with sediment from either the respective animal collection site or from a presumed pristine site near the laboratory in which the tests were performed. These sediments were treated as laboratory controls. Since the same material was not used as controls for all the toxicity tests, the results of testing the controls were not strictly equivalent among the toxicity tests. Nevertheless, the controls served as independent test media for evaluating the viability of the test organisms and the internal consistency of testing procedures. Also, the results from testing the controls were used to determine which samples were indicated to be "toxic," i.e., significantly different from respective controls, in the data analyses. Sediment Sampling. Sediments were sampled in February 1987 with a 0.1m2 Ybung grab sampler (similar to a Van Veen grab sampler). Multiple (usually 6 to 10) grab samples,were taken at each station and the upper 1 cm of sediment was removed with a Teflonlined calibrated scoop and placed in a Teflon-l'ined, stainless steel basin until about 7L of sediment had been accumulated and composited to form each sample. The sediments were then stirred until the composited sample appeared homogeneous. Portions of varying sizes of the composited samples then were removed for each of the chemical and sedimentological analyses and toxicity tests. All toxicity tests were performed with five replicates or aliquots of each of the composited sediment samples. All except the pore water toxicity test were conducted on fresh samples held for no more than 5 days. The details of all of the methods are described in Long and Buchman (1989) (1) and will be only briefly . results were hirhlv correlated with onlv the cbncentrations of toxic sunimarizea nere. U , Solid Phase Sediment Toxicit Test with the Am hi od Rhepoxwnius abronilds. The burro'wing, infaunal amphip&: R . abrbnius, were collected subtidally from West Beach, a relatively rural site off Whidbey Island in puget Sound, using a bottom trawl, Acute lethality was measured in 10-d exposures to test sediments chemicals. The test with S. piirpuruius indicated mutagenicity in several samples that had high hyd"dJn concentrations. The test of pore water with D. gYrociliUfUs was in sensitivity and precision and not correlated highly with the results from the other tests.