The sperm cell toxicity test using the sea urchin, Arbacia punctulata, is a shortterm chronic procedure using fertilization as an indicator of toxicity to marine and estuarine organisms. Toxicity tests of effluents, receiving waters, and single compounds performed as part of the U.S. Environmental Protection Agency's Marine/Estuarine Complex Effluent Toxicity Testing Program, were reviewed to evaluate this method for reliability, precision, seasonal consistency, and sensitivity.
Routine testing was performed using fertile adult urchins maintained in natural seawater aquaria. A 97.7% success rate (control fertilization exceeded 50%) was achieved for 346 tests conducted between June 1986 and November 1989. During this time, four sets of tests using two reference toxicants, copper (as copper sulfate) and sodium dodecyl sulfate (SDS), were conducted to establish intralaboratory test precision. For these sets of 3 to 5 tests each, test precision, calculated as coefficients of variation (CV), ranged from 22.0 to 54.0%. There were no obvious seasonal trends in test success rate, sensitivity, or variability. Sperm test results of these two reference toxicants and 33 complex effluent studies were ranked for sensitivity when compared to results of concurrent short-term chronic marine toxicity tests using marine/estuarine species of algae, mysids, and fish. Of the five test types compared, the sperm test was intermediate in sensitivity.
A second set of fertile urchins were maintained and tested using a noncommercial artificial seawater formulation. These tests were frequently successful and were similar in sensitivity yet slightly less variable (precision test CV's = 10.0 to 41.8%) than those conducted concurrently using gametes from animals held in natural seawater.