ACUTE AQUATIC TOXICITY OF PROTOLYZING SUBSTANCES STUDIED AS THE MICROTOX EFFECT

In tests of acute aquatic toxicity, the effects of protolyzing substan ces varies with pH. The Microtox toxicity of six chlorophenols was stu died over a pH interval and the relation of effects to dissociation wa s examined. The pK(a) values of the chlorophenols under the optimal te st conditions are presented. The results of the Microtox toxicity test s supported a simple model of two species, phenol and phenate, with di fferent specific toxicity. In five of the six chlorophenols only the e ffects of the phenol form were observed. The toxicity of the phenol fo rm was 20 times or more higher than that of the phenate. (C) 1995 Acad emic Press, Inc.