Effect on enzymes and histopathology in earthworm (Eisenia foetida) induced by triazole fungicides

Earthworms are an ideal biological model in toxicity assays and environment monitoring studies, especially for the toxicity of pesticides on soil ecosystem. However, There are very little data on the toxicity of triazoles on earthworms despite the fact that such data are critical in assessing their fate and potential toxic effects in soil organisms. To address this issue, earthworms were exposed to triazoles (triadimefon, triadimenol, difenoconazole and propiconazole) to study biochemical and histopathological examination. The results showed protein content significantly increased in treatment of difenoconazole compared to control. There were no significant differences between controls and triadimefon treated groups, while the glutathione peroxidase (GSH-Px) activity is significantly lower than control. Other triazoles also had an inhibitory effect on GSH-Px activity at higher concentration. The histopathological examination showed the epidermis and the epidermis cell of earthworm was ruined at lower triazoles concentration. The arrangement of smooth muscle layer disordered, and some cell disintegrated with concentration increasing of pesticides. Cell pyknosis, cytoplasm deep stained, nucleus concentrations were observed in the treated group with propiconazole.