Abstract

Background: Pirimiphos-methyl is a potent organophosphate (OP) pesticide used worldwide for the control of pests in stored grains and various insects in domestic, public, agricultural, commercial and industrial settings. However, its pervasive use and broad-spectrum nature could have adverse effects on non-target organisms and the environment which require constant monitoring and assessment. Materials and Methods: In this study, the acute toxicity of pirimiphos-methyl, injected intraperitoneally at concentrations of 833.33, 416.67, 166.67 and 83.33 mg/kg was evaluated. Also, the genotoxic and mutagenic potentials of pirimiphos-methyl were assessed using two eukaryotic assays: The micronucleus and sperm morphology assays in mice, at concentrations of 83.33, 41.67, 20.83, and 8.33 mg/kg. Results: Administration of 416.67 mg/kg pirimiphos-methyl caused 100% mortality in exposed mice under 24 h. Fifty percent mortality resulted from the administration of 166.67 mg/kg dose. There were dose dependent significant increases (P < 0.05) in bone-marrow micronucleated polychromatic and normochromatic erythrocytes as well as aberrant sperms (wrong angle hook, amorphous, banana, no-hook heads, double-tailed and folded sperms) equivalent to the cyclophosphamide induced aberrations. Conclusion: These results indicate that pirimiphos-methyl induced genotoxic damage in exposed mice with consequences for environmental health and safety. These erythropoietic and reproductive changes could be used as biomarkers for monitoring OP pesticide exposed environment.

Key words: Biomonitoring, mice, micronucleus, pesticide, pirimiphos-methyl, sperm