Exposition of marine copepods to organophosphorus xenobiotics: application of acetylcholinesterase biomarkers in the laboratory

Organophosphorus pesticides (OP) are dangerous xenobiotics for aquatic environments mainly because they can interact with all links of the food web inducing bioaccumulation and bioconcentration in organisms. In addition, they have an influence on the enzymes of the cholinergic system (acetylcholinesterase and pseudocholinesterase) of the organisms blocking their catalytic site and causing an excess of excitation of receptors for acetylcholine accumulation. The biomarkers, such as the evaluation of acetylcholinesterase (AChE) inhibition, provide an indication of the pollution level of the environment and are indicators of the ecotoxicological risk for exposed organisms. As small invertebrates are a fundamental link in the food web, the ecotoxicological risk evaluated on these organisms with the biomarker approach can be used as an early evidence of ecosystem damage. In this research copepods collected in the splashpools of the eastern coast of the Ligurian Sea and maintained in the laboratory were utilized as test-organisms. Aim of this work was to evaluate in copepods Tigriopus fulvus the effect of the exposition to the organophosphorus pesticide Malathion (Pestanalâ) on the activity of AChE.