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

Abstract

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.