Cyst Based Toxicity Tests. - VIII. Short-Chronic Toxicity Tests with the Freshwater Rotifer Brachionus calyciflorus
Abstract : The development and potential use of a 4-day static renewal test [4-day Life Table (LT) test] and a 3-day static test [3-day Population Growth (PG) test] with the freshwater rotifers Brachionus calyciflorus are described. For both bioassays, test animals are obtained by hatching cysts wich eliminates the need for the culturing and the maintenance of the organisms. The toxicity of copper (Cu), pentachlorophenol (PCP), 3,4-dichloroaniline (DCA) and lindane was assessed using the developed methods. The NOEC’s, based on the test endpoint rm, obtained with the 4-day LT test were 0.0025, 0.4, 5 and 20 mg/l for Cu, PCP, DCA and lindane, respectively. Similar results were obtained with the 3-day PG test for which NOEC’s of 0.005, 0.8, 20 and 10 mg/l, respectively, were recorded. The mean CV between replicated 3-day PG tests was 10%, indicating a good intra-laboratory reproducibility of the test results. For Cu and PCP, the sensitivity of B. calyciflorus compared favourably to chronic toxicity tests with Daphnia magna, while for the other two compounds B. calyciflorus proved to be rather insensitive. Considering the increasing need for relatively short toxicity tests, the two described short-chronic bioassays could be valuable new tools for routine toxicity evaluations. The major advantages associated with these tests are : they are less labour-intensive than existing chronic tests, they can be completed within one work week, and do not require stock culturing of test organisms.