Integrated use of biomarkers (O:N ratio and acetylcholinesterase inhibition) on Aulacomya ater (Molina,1782) (Bivalvia: Mytilidae) as a criteria for effects of organophosphate pesticide exposition

The effect of residual concentrations of organophosphate pesticide chlorpyrifos (lorsban 4e) on the activity of the acetylcholinesterase enzyme and oxygen:nitrogen ratio in the mussel aulacomya ater was analyzed. toxicity tests show a sensitivity to the pesticide in the bivalve estimated at 16μg l -1 (lc50-96 hours). concentrations between 0.2 and 1.61g l-1 were able to inhibit significantly the ache activity,and concentrations between 0.8 and 1.61μg l-1 stimulate ammonia excretion and decrease oxygen:ammonia-n (o:n) ratio,with respect to the control group. a. ater proved to be a species sensitive to pesticide exposure and easy to handle in lab conditions. thus,it is recommended as a bioindicator for use in programs of environmental alertness in the eastern south pacific coastal zone. copyright 2012 eduardo fhrer et al.