The relative biological response (log BR) for each of 30 select substituted phenols and anilines was evaluated using the 48-h Tetrahymena pyriformis population growth test system. Simple linear regression analysis of log BR versus log Kow (1-octanol/water partition coefficient) was used to formulate a quantitative structure-activity relationship (QSAR). The equation, log BR = 0.438 (log Kow) + 0.157; n=27, r2 =0.933, s = 0.151, f=348.02, is a highly predictive model. An evaluation of data on fathead minnow mortality for these same compounds shows a similar QSAR, log LC50= -0.590 (log Kow)- 3.247; n = 11, r2 = 0.917, s = 0.287, f=99.04. These relationships are the respective QSARs for the respiratory uncoupling mechanism of action of selected weak acids. Moreover, the toxic response in the two systems are highly correlated (r2 = 0.915). © 1990.
