Abstract: A QSAR analysis has been carried out of the toxicity of 47 mono-substituted nitrobenzenes to the aquatic ciliate Tetrahymena pyriformis. The single most important parameter was the logarithm of the apparent partition coefficient (logD) at pH 7.35. 2- and 3-derivatives yielded an excellent correlation of toxicity with log D, Swain-Lupton field parameter and ...