||Relationships of Quantitative Structure-Activity to Comparative Toxicity of Selected Phenols in the 'Pimephales promelas' and 'Tetrahymena pyriformis' Test Systems.
Schultz, T. W. ;
Holcombe, G. W. ;
Phipps, G. L. ;
||Tennessee Univ., Knoxville.;Environmental Research Lab.-Duluth, MN.
Toxic tolerances ;
Linear regression ;
Pimephales promelas ;
Fathead minnow ;
Tetrahymena pyriformis ;
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The relative toxic response of 27 selected phenols in the 96-hr acute flowthrough 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 uncouplig 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. (Copyright (c) 1986 Academic Press, Inc.)