Toxicological effects and oxidative stress responses in freshwater snail, Lanistes carinatus, following exposure to chlorpyrifos.

Chlorpyrifos is a widely used organophosphorous pesticide in agriculture and environmental health. Laboratory studies of chlorpyrifos have revealed acute lethal toxicity at very low concentration (96-h LC50) of 0.39 μg L(-1) to the freshwater snail, Lanistes carinatus. Acetylcholinesterase (AChE) inhibition progressed and reached 52% and 78% of the control after 28-d exposure to 0.09 and 0.29 μg L(-1) chlorpyrifos, respectively. Catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities increased in comparison to control group in the first period of exposure (7-21 d), then decreased relative to the control in the second period of exposure (21-28 d). A significant (p<0.05) glutathione (GSH) depletion was observed in snails exposed to 0.09 and 0.29 μg L(-1) in comparison to the control, whereas malondialdehyde (MDA) content gradually increased in a dose-dependent manner. This study showed that alterations in antioxidant enzyme activities along with depletion of GSH content and elevation of MDA content can be used as biomarkers in environmental assessment programs.