Structure–Toxicity Relationships for the Fathead Minnow, Pimephales promelas: Narcotic Industrial Chemicals

Narcosis is a reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. This nonspecific mode of toxic action was found predominant in acute toxicity studies of industrial chemicals and fish. This paper presents 96-h LC50 values for 65 industrial chemicals including alcohols, ketones, ethers, alkyl halides, and substituted benzenes. The common mode of action permitted the development of a structure–toxicity relationship as follows: log LC50 = −0.94 log P + 0.94 log (0.000068P + 1) −1.25 where P is the n-octanol/water partition coefficient. The data show that the toxicity of the chemicals to fish is directly comparable with the toxicity in mammals when expressed as chemical activity.