Toxicity and histopathological effect of atrazine (Herbicide) on the earthworm <i>Nsukkadrilus mbae</i> under laboratory conditions

Abstract

The toxicity and histopathological effects of the herbicide Atrazine to the earthworm Nsukkadrilus mbae were studied under laboratory conditions. N. mbae were exposed to different concentrations of Atrazine (0.0, 0.4, 0.8, 3.0 and 9.0 mg/kg soil) for 96 hours and mortality was recorded every 24 hour. In addition, sections of the worm were made after 96 hours for microscopic examination. There was no mortality in the control group but in the experiments groups throughout the study. The mortality in the different treatment groups was significantly different (P > 0.05) and was concentration dependent. The LC50 of Atrazine after 24, 48, 72 and 96 hours were 8.60, 7.05, 7.37 and 7.23 respectively. The histopathological manifestations of exposing N. mbae to the herbicide included damage to the chloragogenous layer, damage of the epithelial tissues; glandular enlargement of the epithelial tissues, prominent vacoulations and pyknotic cells. The result of the study showed that both mortality and histopathology data could be used in environmental risk assessment of Atrazine.