Abstract
Pesticides are designed to kill a very wide range of undesirable organisms, but they simultaneously adversely affect non-target organisms in ecosystems. Dimethoate is an organophosphorous insecticide used widely in agriculture that has an anticholinesterase mode of action. The goal of the study was to assess the effects of dimethoate on catalase, reduced glutathione, and lipid peroxidation in the gills and livers of zebrafish, Danio rerio (Hamilton), exposed to different concentrations of the pesticide for different periods of time. Insecticidal stress caused a reduction in catalase activity and reduced glutathione levels in zebrafish gills and livers. There was also increased lipid peroxidation in both organs. Alterations in all parameters were concentration and time dependent. The probable causes are discussed.