The impact of anthropogenic activities on the Fosu Lagoon in the Central District of Cape Coast: Integrated Assessment of Heavy Metal Contamination

Abstract

Effluents from humans and industrial discharges into the environment pose a serious threat to human health and aquatic life. In view of this, levels of some heavy metals Zn, Pb, Cu, Ti, V and Mn were determined in sediment samples collected from one of the most polluted water bodies (Fosu Lagoon) in the central region of Ghana using Atomic Absorption Spectrophotometer (AAS) - (Varian – AA240 FS). The average concentrations of lead (Pb), zinc (Zn), manganese (Mn), copper (Cu), Titanium (Ti) and Vanadium (V), from the various sites ranged from 138.75 mgkg -1 (Ti) to 4.90 Mgkg -1 (Zn). Among the concentrations of heavy metals found in the sediment samples, Ti recorded the highest concentration of 4600 mgkg -1 followed by Mn (290.00 mgkg -1) and then Cu (235.93 Mgkg -1 ). The sequence of distribution followed Ti>Mn˃V>Cu>Pb˃Zn. The mean concentration of Mn, Cu, Ti and V exceeded the USEPA and WHO standard guideline whiles Pb and Zn were below the standard regulation limits. The Pearson correlation analysis between the heavy metals at the various sampling points was generally weak, with both positive and inverse correlations demonstrating that heavy metals may be coming from different anthropogenic sources. Comparing results from this study with previous works in the same Lagoon showed increased anthropogenic activities around the lake which pose potential pollution threats to the lagoon especially, the heavy metal pollutants which may be toxic to humans and aquatic life– AA240 FS). The average concentrations of lead (Pb), zinc (Zn), manganese (Mn), copper (Cu), Titanium (Ti) and Vanadium (V), from the various sites ranged from 138.75 mgkg -1 (Ti) to 4.90 Mgkg -1 (Zn). Among the concentrations of heavy metals found in the sediment samples, Ti recorded the highest concentration of 4600 mgkg -1 followed by Mn (290.00 mgkg -1 ) and then Cu (235.93 Mgkg -1 ). The sequence of distribution followed Ti>Mn˃V>Cu>Pb˃Zn. The mean concentration of Mn, Cu, Ti and V exceeded the USEPA and WHO standard guideline whiles Pb and Zn were below the standard regulation limits. The Pearson correlation analysis between the heavy metals at the various sampling points was generally weak, with both positive and inverse correlations demonstrating that heavy metals may be coming from different anthropogenic sources. Comparing results from this study with previous works in the same Lagoon showed increased anthropogenic activities around the lake which pose potential pollution threats to the lagoon especially, the heavy metal pollutants which may be toxic to humans and aquatic life