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EVALUATION OF THE ROBUSTNESS OF THE FATHEAD MINNOW, PIMEPHALES PROMELAS, LARVAL SURVIVAL AND GROWTH TEST, U.S. EPA METHOD 1000.0
Citation:
Pickering, Q. AND J. Lazorchak. EVALUATION OF THE ROBUSTNESS OF THE FATHEAD MINNOW, PIMEPHALES PROMELAS, LARVAL SURVIVAL AND GROWTH TEST, U.S. EPA METHOD 1000.0. Environmental Toxicology and Chemistry 14(4):653-659, (1995).
Description:
An intralaboratory study was conducted to evaluate the robustness of the Fathead Minnow (Pimephales promelas) Larval Survival and Growth Test, Method 1000.0 Toxicity tests were conducted with the reference toxicants hexavalent chromium (Cr6+) and copper (Cu), and the data were statistically analyzed using hypothesis testing. Differences in age, size, feeding regimes, and water quality did not cause more than a twofold difference in 13 subchronic values (SCVs) for Cr6+. These tests involved side-by-side tests initiated with 1-,4-, and 7-d larvae or initiated with 1-d larvae and two size groups of 4-d larvae fed differently. The mean SCV was 3,600 ug Cr6+/L, and the values ranged from 2,100 to 4,200 ug Cr6+/L. Eleven of these tests with a homogeneous variance gave an average minimum significant difference (MSD) of 14.3%. The no-observed-effect concentration (NOEC) for growth was always lower than the effect on survival. In the side-by-side tests with 1-,4-, and 7-d larvae exposed in hard water the SCV was 35 ug Cu/L for each age group. Except for one test with Cu in soft water, the effects of Cr6+ and Cu on growth were more sensitive than the effect on survival. These toxicity tests along with some nontoxicant studies indicated that reasonable differences in methods parameters did not cause any changes greater than a factor or two in analytical results despite the "noise" of biological variability.