Relative Toxicity of Ten Chlorinated Hydrocarbon Insecticides to Four Species of Fish

Abstract

Bioassays were conducted on ten commonly used chlorinated hydrocarbon insecticides to determine their comparative toxicity to fish. All of the compounds except BHC were extremely toxic to fish with 96 hour TLm values generally below 0.1 p.p.m. Endrin was the most toxic with TLm values ranging as low as 0.6 p.p.b. Bluegills were the most sensitive fish, followed by fathead minnows, goldfish and guppies, respectively. Changes in water quality characteristics (pH, alkalinity, hardness) had no apparent effect on toxicity. Acetone solutions and emulsible concentrates were equally toxic and were the most toxic formulations. All of the chlorinated hydrocarbon insecticides except BHC were more toxic to fathead minnows than the most toxic of the organic phosphorus insecticides. Additional areas of needed research are suggested.