Copper, lead, zinc, iron, manganese and volatile matter concentrations were determined in surface sediments samples, a dissected sediment core, suspended matter and in the oyster Crassostrea rizophorae, taken from Manati Bay, Cuba. In sediments, normalization of heavy metal contens to volatile matter expedited the intrepretation of results and allowed to distinguish the discharge zone of waste waters from a sugar cane factory and the Manatí village as affected by Cu and Zn. The studied species showed seasonal variations during the period, but was not useful as bioindicator of heavy metal pollution; tihs fact seems to be caused by the enviromental conditions of the zone.