A simplified procedure for conducting small scale short-term embryo toxicity tests with salmonids

Abstract

A method for conducting short-term (7 day) embryo toxicity tests with rainbow trout is described. The test uses an easily recognizable endpoint that incorporates fertilization success, embryo mortality, and morphogenesis. Method validation included 26 tests on pulp and paper mill effluents and 10 tests with the reference toxicant sodium dodecyl sulphate. The results demonstrate that the method is sensitive and reproducible. Sensitivity, as measured by the minimum statistically significant response, averaged 15.5% of the control performance. Control embryo viability averaged 90% over 36 tests, indicating that the test procedures are robust with low probability of failure. Reference toxicant test results suggested that the short-term embryo toxicity tests were appreciably more sensitive than 96 h acute tests with juvenile rainbow trout and 7 day fathead minnow larval survival and growth tests. This test offers the potential for conducting routine toxicity tests where cold water salmonids are the species of interest and it is desirable to use a more sensitive measure of effects than a 96 h LC50 acute toxicity test with juvenile fish. ©1999 John Wiley & Sons, Inc. Environ Toxicol 14: 301–307, 1999