Integrated Use of Biomarkers (O : M Ratio and Acetylcholinesterase Inhibition) on Aulacomya ater (Molina, 1782) (Bivalvia: Mytilidae) as a Criteria for Effects of Organophosphate Pesticide Exposition

摘要

The effect of residual concentrations of organophosphate pesticide chlorpyrifos (Lorsban 4E) on the activity of the ace-tylcholinesterase 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 16 mug L~(-1) (LC_(50-96hours)). Concentrations between 0.2 and 1.61 mug L~(-1) were able to inhibit significantly the AChE activity, and concentrations between 0.8 and 1.61 mug 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.