Assessment of Metal and Heavy Metal Concentrations in the Angola Catchment, Freetown, Sierra Leone

Abstract

The study examines the levels of heavy metals in the Angola Catchment Area of Freetown, Sierra Leone, and their potential impacts on human health and the aquatic ecosystem. Monthly water samples were collected from March to December 2024 at three distinct locations: upstream, midstream, and downstream, totalling ten months of data collection. Seven heavy metals were analyzed: arsenic (As), manganese (Mn), copper (Cu), iron (Fe), zinc (Zn), lead (Pb), and chromium (Cr). The results indicated that chromium, and manganese levels consistently exceeded the World Health Organization (WHO) recommended limits. In contrast, lead and arsenic were undetectable at all three sampling sites. These findings raise significant environmental concerns regarding heavy metal contamination, which poses health risks to both aquatic organisms and the local population due to the potential for bioaccumulation. The study underscores the urgent need for enhanced monitoring and regulation of human activities to mitigate the adverse effects of these hazardous metals in water bodies.