The use of cholinesterase and carboxylesterase activities fromMytilus galloprovincialisin pollution monitoring

Abstract Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carboxylesterase (CbE) activities have been measured in gills and digestive gland of the mussel Mytilus galloprovincialis. AChE activity was predominantly localized in gills, whereas the highest BChE and CbE specific activities were detected in digestive glands. Commonly used pesticides were examined in vitro for their ability to inhibit mussel esterases; the results obtained pointed out the highest sensitivity of mussel CbE to low concentrations of pesticides, but also the higher sensitivity of gill cholinesterases over digestive gland forms. Seasonal variation in the activity of gill esterases was determined monthly in mussels collected from the Ebro Delta, an area where pesticides and biocides are frequently used. As a general trend, elevated cholinesterase activities were detected in winter, possibly indicating little or no exposure to organophosphorous compounds, whereas the lowest cholinesterase activities were reported over the summer period. These changes were related to agricultural activities in the area and are supported by the detection of organophosphorous pesticides in the tissue of M. galloprovincialis.