Examining the suitability of mussel digestive gland to serve as a biomonitoring target organ.

In coastal marine areas, the level of metallothioneins (MTs) is monitored as the specific response to trace heavy metals and is considered as a biomarker of metal exposure. Laboratory experiments with bivalves indicate that MT synthesis is induced by Cd, Cu, Hg, Ag and Zn ions. The results of our study, conducted with the mussel Mytilus galloprovincialis, deployed 12 months in the "hot spot" area of the Kastela Bay, Dalmatia, Croatia, are evaluated considering the recommendation of MED POL Programme for estimating exposure of mussels to trace heavy metals by means of MTs. Our data clearly indicate that the MT level in the digestive gland of the Mediterranean mussel depends on the biotic and abiotic parameters. Beside MT level, a number of parameters, like digestive gland mass, shell mass, cytosolic metal concentration is needed in order to define if MT level in the digestive gland of mussels is indicative as a biomarker of cadmium exposure.