Exposition biomarkers to organophosphorus pesticides in Tigriopus fulvus Fischer (Copepoda, Harpacticoida)

The effects of the organophosphorus pesticide Malathion, Pestanal^® on the activity of the enzymes Acetylcholinesterase (AChE) and Glutathione-S-transferase and on survival were evaluated in Tigriopus fulvus. The mortality of the organisms after 96 hours (acute toxicity) and after 7 days (chronic toxicity) of treatment was evaluated. LC₅₀ was not calculable after 24 hours of exposition; after 48, 72 and 96 hours it resulted 905.72, 552.78, and 248.94 μg I^-1 respectively. After 7 days the NOEC value was 25 μg I^-1. The LOEC value for the inhibition of AChE was 25 μg I^-1 and for the stimulation of GST was 12.5 μg I<sup>-1