Abstract: The river Pra whose estuary was analyzed passes through very important gold mining communities in Ghana. This makes it important to study the bio-accumulation levels of cadmium and mercury in some selected biological species which is fished from the estuary. This piece of work determined the levels of the metals mercury and cadmium in selected biological species namely tilapia, mudfish, prawns, crabs and mollusk from the River Pra Estuary using the Instrumental Neutron Activation Analysis (INAA) technique. The samples were taken every fortnight from four sampling sites from Beposo to the Shama Beach in the Western Region of Ghana for two and half months.  It was observed that the River Pra had elevated levels of the metals and the concentrations ranged between <0.001 - 0.005 µg/g wet weight (ww) for mercury and <0.001 - 0.012 µg/g wet weight (ww) for cadmium. There is some level of contamination of the Pra river estuary with mercury and cadmium. The sources of these metals though diffused, there is every indication that mining operations up stream may have contributed to the heavy metal load of the estuary.

KEYWORDS: Mercury, Cadmium, Pra estuary tilapia, mudfish, prawn, crab and mollusk