THE USE OF CHOLINESTERASE AND CARBOXYLESTERASE ACTIVITIES FROM MYTILUS-GALLOPROVINCIALIS IN POLLUTION MONITORING

Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carboxy lesterase (CbE) activities have been measured in gills and digestive g land of the mussel Mytilus galloprovincialis. AChE activity was predom inantly 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 Cb E to low concentrations of pesticides, but also the higher sensitivity of gill cholinesterases over digestive gland forms. Seasonal variatio n in the activity of gill esterases was determined monthly in mussels collected from the Ebro Delta, an area where pesticides and biocides a re frequently used. As a general trend, elevated cholinesterase activi ties were detected in winter, possibly indicating little or no exposur e to organophosphorous compounds, whereas the lowest cholinesterase ac tivities were reported over the summer period. These changes were rela ted to agricultural activities in the area and are supported by the de tection of organophosphorous pesticides in the tissue of M. galloprovi ncialis.