Assessment of multimarker responses in Perna perna,Mytilus galloprovincialis and Donax trunculus bivalves exposed to malathion and 2,4- dichlorophenoxyacetic acid pesticides

The early biological effects of pesticides was assessed in three species of bivalves: perna perna,mytilus galloprovincialis and donax trunculus,exposed to 500 μg/l of malathion mal (organophosphorous pesticide; op) and 2,4- dichlorophenoxyacetic acid 2,4-d (organochlorinated pesticide; oc). the responses of acetylcholinesterase (ache,biomarker of neurotoxicity),glutathione s-transferase (gst,biomarker of detoxification) and catalase activities; and malonedialdhyde levels (cat and mda; biomarkers of oxidative stress and lipid peroxidation) were characterized. the mortality rate of bivalves was determined as biomarker of general stress. the results revealed critical alterations of the measured sub-cellular parameters. the alterations of the biomarkers responses depend on the pesticide and time of exposure. ache showed a significant inhibition in all species along the experiment; which could be explained by neurotoxic effect due to the high sensitivity of ache to pesticides,especially organophosphorous compounds. while,gst activity was significantly increased (p< 0.01) after 24h of exposure to 2,4-d (85 % of induction in p. perna at 48h). cat activity and lipid peroxydation were induced after 12h of exposure to pesticides indicting a high generation of free oxyradicals. meanwhile,mortality increased progressively according the exposure time (more than 30%). the multimarker responses used in these experiments demonstrated clearly the early biological effects (biochemical dysfunctions) and mortality rate increase of perna perna,mytillus galloprovincialis,donax trunculus exposed to the sub-lethal concentration of malathion and 2,4-dichlorophenoxyacetic acid pesticides.