Evaluation and comparison of two short-term fathead minnow tests for estimating chronic toxicity

Abstract

The purpose of this study was to evaluate and compare the fathead minnow larval survival and growth test (larval test) and the fathead minnow embryo-larval survival and teratogenicity test (embryo-larval test). These tests were developed for use by the U.S. Environmental Protection Agency regional and state programs and the National Pollutant Discharge Elimination System permittees to estimate the chronic toxicity of effluents and receiving waters. Five larval tests with the reference toxicant, sodium pentachlorophenate, gave a mean subchronic value of 253 μg 1 −1 with a relative standard deviation of 39%. The mean LC 50, LC 10 and LC 1 values and their relative standard deviation for the embryo-larval test were 313 ± 6.4%, 224 ± 18% and 172 ± 27% μg 1 −1, respectively. The mean subchronic value for six larval tests with the reference toxicant, sodium dodecylsulfate was 6.0 mg 1 −1 with a relative standard deviation of 23%. The mean LC 50, LC 10 and LC 1 values for the embryo-larval test were 5.8 ± 2.6% 4.2 ± 5.9% and 3.3 ± 9.4% mg −1, respectively. Both types of test methods had a high-low ratio of no observable effect concentration values of 2, the reciprocal of the dilution factor. The mean subchronic value for four larval tests with linear alkylbenzene sulfonate was 2.1 mg 1 −1 and the subchronic values ranged from 1.7 to 3.4 mg 1 −1. Side-by-side tests were conducted with three effluents and hexavalent chromium. The larval test was more sensitive to two of the effluents and hexavalent chromium. The low test concentration of the third effluent caused an adverse effect in both tests.