Variability in the performance of the seven‐day fathead minnow (pimephales promelas) larval survival and growth test: An intra‐ and interlaboratory study

Abstract

The U.S. Environmental Protection Agency (EPA) has developed a “Seven‐Day Fathead Minnow Larval Survival and Growth Test” for measuring the toxicity of effluents. This study evaluated the ease and performance and the intra‐ and interlaboratory variability of this 7‐d test using two reference toxicants (sodium pentachlorophenate and potassium dichromate), two refinery effluents, and one low‐volume internal waste stream from an electric power plant. Ten different laboratories representing academia, private industry, contractors, the state EPA, and the U.S. EPA participated in this study. The reference toxicants were tested twice during two separate test periods, and each effluent and waste stream was tested once. Using EPA's criteria for a successful test, 90% of the 140 planned tests were completed as valid tests. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted concurrently (spatial variability), expressed as the coefficient of variation (C.V.), ranged between 5.9 and 15.6% and between 9.1 and 26.1%, respectively. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted at two different times (temporal variability), expressed as C.V., ranged between 14.5 and 25.3% and between 17.6 and 22.7%, respectively. The interlaboratory variability of the survival (LC50) and growth (IC50) results, expressed as C.V., ranged between 24.1 and 43.7% and between 22.4 and 88.0%, respectively. Overall, the variability of the 7‐d fathead minnow test was similar to the variability observed with other toxicity tests and with analytical chemistry measurements of environmental samples.

Assessing Contaminant Sensitivity of Endangered and Threatened Aquatic Species: Part I. Acute Toxicity of Five Chemicals

“…The representativeness of various species as identified in the present study would also be consistent with Stephan et al (1985) who stated that "results of acute and chronic toxicity tests with representative species of aquatic animals are necessary so that data available for tested species can be considered a useful indication of the sensitivities of appropriate untested species." It has been shown that intralaboratory tests may range up to a factor of twofold for the same species-chemical test combinations (Schimmel 1981;Lemke 1981;DeGraeve et al 1991). In the present study, only five 96-hour LC50s fell below a factor of 0.5 (intralaboratory variation) and three of those were for sturgeon.…”

Accuracy assessment of time–concentration–effect models in predicting chronic lethality from acute toxicity data

“…The factor of two or five times is statistically based because previous intra-and interlaboratory acute and chronic toxicity test comparisons [21][22][23][24] demonstrated that a twofold difference (i.e., highest to lowest toxicity values) existed for the same species-chemical combinations and methodology for intralaboratory tests. The factor for interlaboratory tests was five times.…”

Precision and Sensitivity of a Seven-Day Growth and Survival Toxicity Test Using the West Coast Marine Mysid Crustacean Holmesimysis Costata

“…Evaluating precision is the primary means of determining the reliability of a toxicity test method for use as a regulatory tool [30]. Toxicity test accuracy cannot be measured, because the response of a test organism cannot be compared to a standard or reference value [25].…”