Impact assessment of heavy metal pollution in the municipal lake water, Yaounde, Cameroon

The objectives of this study are to evaluate the extent of heavy metal pollution in water at the Municipal Lake of Yaounde, and to find out their variability and origin. Water from fifteen selected sites of the lake and River Mingoa, Cameroon was sampled in August 16 th of 2005 and 2006 and in 30 th August 2007 during the minor dry season; and subjected to the analyses of physicochemical parameters and various elements. In addition, multivariate data analysis techniques including principal component analysis (PCA) were utilized to determine the variations in heavy metal content in the Municipal Lake water and their natural or anthropogenic sources. The chemical results indicated that concentrations of Al, Fe, Mn, Cd and Pb in the study area exceeded the drinking water quality and they would pose health risk for users of these waters. This is evidence that River Mingoa, the main tributary to the Municipal Lake is the main collector of pollutants from activities in the sloping side of the Municipal Lake. Based on the multivariate statistical analysis, very high positive correlations were observed between elements, and five factors computed from PCA explained 86.6% of total variance. These factor loadings are mainly controlled by anthropogenic inputs, lithogenic processes during weathering progress of natural parent materials and local geology.