Acute toxicity of acetochlor for zebrafish (Danio rerio) and guppy (Poecilia reticulata)

We determined acute lethal toxicity of herbicide Acctochlor for two species of fish: guppy and zebrafish, each in two different stages of development. For adult individuals of guppy the 96-h LC50 was 1.7 mg/l, for juvenile guppy LC50 represented for the same time of exposure 1.3 mg/l. LC50 of a 96-h exposure for adult individuals of zebrafish represented 0.37 mg/l and for embryos of zebrafish in eggs the 96-h LC50 was 0.61 mg/l. In contrast to mammals, fish were found to be much more sensitive to Acetochlor. The tested herbicide belongs to a highly toxic substance for guppy or to a very highly toxic substance for zebrafish. Comparing our results to already reported data on mammals we may consider Acetochlor very hazardous xenobiotics for fish as it was 500 to 10 000 times more toxic for fish than for mammals.