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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 520

Schultz, T.W., Holcombe, G.W., and Phipps, G.L.; Relationships of quantitative structure-activity to comparative toxicity of selected phenols in the Pimephales promelas and Tetrahymena pyriformis test systems. Ecotoxicol. & Environ.Safety 12:146-153, 1986

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The relative toxic response of 27 selected phenols in the 96-hr acute flow through Pimephales promelas (fathead minnow) and the 48- to 60-hr chronic static Tetrahymena pyriformis (ciliate protozoan) test systems was evaluated. Log Kow-dependent linear regression analyses revealed that the data from each test system consisted of two linear equations. The less toxic chemicals form a relationship which models polar narcosis; these chemicals are slightly more active than the baseline toxicity of nonionic narcotic chemicals. The more toxic chemicals form a relationship which models uncoupling of oxidative phosphorylation. Regression analysis of fathead minnow toxicity (log LC50 (mol/liter] vs Tetrahymena toxicity (log BR (mmol/liter] showed good correlation between the two systems. An exception appears to be 4-nitrophenol, which is more active in the Tetrahymena system than in the fathead minnow and lies outside the 95% confidence interval. Reanalysis following deletion of 4-nitrophenol results in the equation log LC50 = -0.9192 (log BR) -3.5035; n=26, r(2)=0.887.