Etude des mécanismes de transferts des éléments métalliques dans les chaînes alimentaires aboutissant à l'huître et à la moule, mollusques filtreurs, formes chimiques de stockage, conséquences écotoxicologiques

The first part of this report describes a field study which took place in the Bay of Bourgneuf during more than two years. In this area, the filterfeeding molluscs show metal concentrations which are generally low compared to those determined in other worldwide sites. In these conditions, the characteristics of bioaccumulation (seasonal and pluri-annual fluctuations) and organo-tropism can be considered, to a large extent, as the consequence of the normal metabolism of trace elements. A statistical analysis of relations between the respiratory type of marine Gram negative bacilli and their resistance to zinc and cadmium, or their ability to concentrate zinc was carried out on 453 strains isolated monthly from seawater and oyster, of the Bay of Bourgneuf during an annual cycle. A highly significant relation is shown between the respiratory type and both the toxicological characteristics.