Effect of anthropogenic activities on an ecologically important wetland in Ghana

Abstract The objective of this research was to assess the level of pollution in the Sakumo wetland with emphasis on heavy metals contamination and their distribution in the wetland, which is being polluted from industrial, domestic and sewage effluents. Samples of water, sediment and fish were collected and analyzed for the concentration of heavy metals (arsenic, cadmium, chromium, copper, iron, mercury, nickel and zinc) using atomic absorption spectrophotometry (AAS). The sequence of order of the heavy metals in the water, sediment and fish samples observed in the wetland was as follows: Fe > Mn > Cu >Hg, Mn > Fe> V> Cr > Cu >Zn ≈ As >Co > Cd > Hg, Fe > Cu > Mn> V> Hg > Cd respectively. The results showed high levels of copper and managanese in all three samples (water, sediment and fish) however, mercury and cadmium were available in relatively low concentration in the fish samples. Sampled sediment materials revealed highest concentrations of the heavy metals. Fe, Mn, and Zn concentration in fish samples were higherr than WHO/FAO recommended values; however, these heavy metals did not pose any immediate health risk to humans. It is possible however, that, the concentration of these heavy metals may increase in wetland and subsequently in the fishes (and other animals) living within the wetland. Hence, the need for regular monitoring of these heavy metals in the wetland resources is important.