LEAD, CADMIUM, COPPER AND IRON IN WATER, SEDIMENT, Galatea paradoxa AND Macrobrachium raridens SAMPLES FROM THE VOLTA ESTUARY AT ADA, GHANA

The concentrations of four heavy metals (Pb, Cd, Cu and Fe) were determined in water, sediments, Galatea paradoxa (clam) and Macrobrachium raridens (Prawn) from Ada fishing site at the Volta Estuary in Ghana using Atomic Absorption Spectrophotometer (AAS). The mean metal concentrations in water were 0.21, 0.02, 1.74 and 0.04 mg/kg for Pb, Cd, Cu and Fe, respectively whilst those in the sediments were found to be 1.18, 2.08, 0.98 and 1336.13 mg/kg for Pb, Cd, Cu and Fe, respectively. The levels of Pb and Cd were above the WHO and EPA permissible limits for water whilst Cd and Fe were found to be above the IAEA permissible limits for sediment metal concentration. The mean metal concentrations in the Galatea paradoxa and Macrobrachium raridens tissues were 2.20, 4.01, 45.25, 104.41 and 4.28, 5.87, 110.03, 64.95 mg/kg for Pb, Cd, Cu and Fe, respectively. The level of concern (LOC) in shell fish consumption for Pb, Cd, Cu and Fe were 2.95, 0.11, 42.11, 736.84 mg/kg, respectively. The risk quotient for Macrobrachium raridens to Galatea paradoxa samples were 1.45 : 0.75, 55.91 : 38.19, 2.61 : 1.08, 0.09 : 0.14 for Pb, Cd, Cu and Fe, respectively. The study established that health risk associated with the consumption of the M. raridens and G. paradoxa species from the Volta estuary at Ada with regards to the four metals (Pb, Cd, Cu, and Fe) is very significant.