Neurotoxicity and oxidative stress induced by permethrin in gills of the freshwater musselUnio ravoisieri

Pyrethroids are contaminants found in the aquatic environment, and their toxicological effects on aquatic organisms have received extensive attention. However, the impact on freshwater bivalve of exposure to these chemicals is still largely unknown. Freshwater mussels Unio ravoisieri were exposed to two nominal permethrin (PM) concentrations C1 = 50 µg/L and C2 = 100 µg/L during 7 days. The measured concentrations of PM using gas chromatography (GC/ECD) in the treated aquariums were, respectively, 28.7–62.3 µg/L. Catalase (CAT), Glutathione-S-transferase (GST), and Acetylcholinesterase (AChE) activities, Glutatione (GSH) and Malondialdehyde (MDA) levels were determined in gills of U. ravoisieri. Significant increase in CAT activity by the lowest concentration and decrease by highest concentration were observed. Additionally, GST activity was increased in a concentration-dependent manner. However, statistically significant decrease in GSH levels (about 39%) was observed only at high concentration of this compound (100 µg/L). PM generated an increase in MDA levels reaching the highest value at the high concentration. AChE activity of mussel ranging from 51% inhibition at lowest concentration 50 µg/L to 89% inhibition at highest concentration 100 µg/L. The results indicated that oxidative stress and cell damage might be one of the main mechanisms of PM toxicity to freshwater mussels.