Determination of Heavy Metal Concentration in Surface Waters of the Western Highlands of Cameroon

Abstract

Heavy metals originating from the use of fertilizers and pesticides are toxic pollutants that limit the beneficial use of water for agricultural, domestic and industrial applications. Three vegetable production basins in the Western Highlands of Cameroon (Bafou, Foumbot and Santa) were surveyed in March 2013, to determine the concentration of heavy metals (Pb, Cd, Cu, Fe, Mn) in surface water. A total of 21 surface water samples were collected and transported to the laboratory where heavy metals were analyzed with a flame Atomic Absorption Spectrometer (AAS). Analysis of variance was carried out to show differences in the heavy metal concentrations from the different basins using SPSS. Results showed that surface water was slightly acidic pH (6.2-7.0). Cd, Pb, Fe, Cu and Mn concentrations ranged between 0.002-0.042, 0.016-1.555, 0.001-0.200, 0.026-1.506 and 0.001-0.519 mg/L respectively. Highest mean concentrations of Cd (0.019 mg/L) and Cu (0.122 mg/L) were observed in Foumbot, Fe (0.420 mg/L) and Mn (0.054 mg/L) in Bafou and Pb (0.322) in Santa. Results showed no significant differences (p>0.05) in mean concentrations of Pb, Cu, Fe and Mn in these basins. Concentrations of heavy metals in water were significantly higher (p<0.05) than those of their control. Generally, results revealed that some heavy metals (Pb, Fe and Mn) were higher than WHO permissible limits while Cd was detected above both the World Health Organization and Food and Agriculture Organization of the United Nations safe limits which can pose health risks to the consumers. Consequently, regular monitoring is needed to alert farmers when heavy metal concentration in water is above safe limits.