Assessment of Water Quality and Heavy Metal Levels in Water and Bottom Sediment Samples from Mokwe Lagoon, Accra, Ghana

摘要

The current study deals with the physicochemical characteristics of water samples from the Mokwe Lagoon in addition to trace heavy metals (Cd, Cr, Ni, Pb and Zn) in the lagoon water and bottom sediments. The results indicated relatively high ionic content which was reflected in high conductivity, total dissolved Solids, alkalinity, hardness and chloride levels; and low nutrient content. The trace heavy metal levels in the lagoon water were found within good range of international guideline limits for natural waters. In contrast, the metallic levels in the sediment were high. The levels of metal contamination and distribution in the sediment samples were assessed using geoaccumulation index, enrichment factor, contamination factor and pollution load factor. The metal index analysis indicated high enrichment of the metals (especially Cr and Ni) which reflected anthropogenic effects of contamination attributable to several sources. The study calls for constant environmental monitoring to forestall any heavy metal hazard which could be detrimental to the aquatic ecosystem of the lagoon.