Determination of selected heavy metals and iron concentration in two common fish species in Densu River at Weija District in Grater Accra Region

Abstract

The concentrations of heavy metals namely; Manganese, Cadmium, Lead, Mercury and Arsenic (Mn, Cd, Pb, Hg and As) including Iron (Fe), were determined in catfish and tilapia samples from Densu River at Weija in 2012. The fish Muscles were carefully dissected for digestion and the levels of heavy metals were determined using Microwave Milestones Ethos 900 double beam Atomic Absorption Spectrophotometer (AAS). Concentrations of heavy metals in the fish samples analyzed in descending order of Fe > Mn > Cd were detected, but, the rest (Pb, Hg and As) were not detected. The highest concentration of Cadmium (0.808mg/kg) was detected in the muscles of Catfish while the lowest value (0.129mg/kg) in Tilapia. The lowest concentration of Mn (0.78mg/L) and Iron (44mg/L) were detected in catfish whereas the highest Mn = 1.74mg/L, Fe = 53mg/L were in the Tilapia samples. Cadmium and Iron accumulated by the two fish species exceeded the maximum permissible limits prescribed by the World Health Organization guideline well as the Food and Agriculture Organization standard. Higher levels of heavy metals accumulated by the fishes might be due to increase in the agricultural influx waters, domestic wastes and some anthropogenic activities which merit further investigation