In vitro heavy metal uptake and MT induction by filterers Bivalves during sediment aeration.

The aim of the present work was to find out a relationship between bioaccumulation in Mytilus galloprovincialis, load of heavy metals (Cu, Zn and Hg) in polluted sediment and role of resuspension in increasing bioaccumulation. A sea-water aerated microcosmo was recreated in a glass tank, subdivided in two non-communicating subtanks, with a bottom layer of sediment from the Guanabara Bay, Rio de Janeiro, Brazil. A special glass instrumentation, MODUS, based on air-lift principle, allows the water oxygenation tangentially to the bottom sediment without resuspension (sub-tank 1) while in sub-tank 2 the sediment was re-suspended by a propeller. Mussels were placed in both sub-tanks for 28 days and regularly sampled. The analysis of both groups of mussels were compared in order to assess if and how sediment resuspension is responsible for higher bioaccumulation of heavy metals. Soft tissue and hepatopancreas metal contents were used as contaminant uptake marker, while MT concentration into digestive gland was used as biomarker.