Regression and cluster analysis of the acute toxicity of 267 chemicals to six species of biota and the octanol/water partition coefficient.

The acute toxicities of 267 compounds to six aquatic and one terrestrial species were investigated with correlation, principal component and cluster analysis techniques for relationships with each other and with the compounds' octanol/water partition coefficient. Selection of the investigated chemicals was based on the availability of at least three of the following measured parameters: acute (24-h to 96-h) lethal concentrations (LC50) to the fish fathead minnow (Pimephales promelas), the fish goldorfe (Leuciscus idus melanotus), the zooplankter Daphnia magna, the ciliate Tetrahymena pyriformis, and the algae Scenedesmus quadricauda; the (30-min) inhibitory concentrations (EC50) to the luminescent marine bacterium Photobacterium phosphoreum (the Microtox test); the acute oral dose (LD50) for the common Norway rat and the octanol/water partition coefficient (log P or log Kow). The results indicate highly significant correlations between the fathead minnow, goldorfe and Daphnia LC50 and the Photobacterium EC50 concentrations. The cluster and principal components analyses did not detect any clearly defined groups of compounds. The toxicities were also highly collinear with the octanol/water partition coefficients for all species except the rat, where two relationships are indicated, with the division at log P = 2.00.