Impact of Inorganic Contaminants from Dumpsite Leachates on Natural Waters in the Enugu Metropolis, South Eastern Nigeria

Abstract

This study evaluates the impact of inorganic contaminants from dumpsite leachates on the quality of the natural water sources in the Enugu metropolis. The concentration of cations including sodium (Na⁺), calcium (Ca²⁺), and potassium (K⁺) and anions such as manganese (Mg²⁺), bicarbonates (HCO₃^–), sulphates (SO4^2–) and chlorides (Cl^–) were analyzed in 9 surface and groundwater samples collected from the study area. Laboratory analyses of the samples reveal a concentration range of 8.05 – 20.15 mg/l for sodium, 0.15 - 8.11 mg/l for calcium, 0.11 – 1.03 mg/l for potassium, 0.02 – 3.04 mg/l for magnesium, 16.88 – 65.66 mg/l for bicarbonates, 14.28 – 60.99 mg/l for sulphate and 10 – 22.69 mg/l for chlorides in the natural waters of the study area. A general trend among the mean values of the cations in the water show that Na⁺>Ca²⁺>K⁺>Mg²⁺ while the anion levels in the water samples are in the order HCO₃^– > SO4^2–>Cl^–. Three water types were identified, based on characterization in the Piper trilinear diagram. They include Na-Mg-HCO3, Ca-Mg-SO₄  and Ca-Mg-Na-K-Cl-SO₄^2- which are reflective of the contribution of various wastes in the area such as corrosive metals and sewage. In general, both water sources are alkaline to strongly acidic with all the tested inorganic parameters having concentrations that fall within the WHO acceptable limits. However, very high chloride values were recorded in the leachates indicating the possibility of organic contamination of the natural waters in the area.