Assessment of the quality of groundwaters proximal to dumpsites in Awka and Nnewi metropolises: a comparative approach

Abstract

Using integrated geoscientific approach, this paper assessed the quality of groundwaters around open dumpsites in Awka and Nnewi metropolises, Nigeria. Ten water samples for each of the metropolises were subjected to hydrogeochemical analysis. Seventeen parameters were subjected to correlation, factor, cluster, pollution index, and quality analyses. The interrelationships between parameters were obtained. The order of cation and anion dominance in Awka is Ca > Mg > Na > K and Cl > HCO3 > SO4 > NO3 > PO4, respectively. In Nnewi, the order is Na > Ca > K>Mg and Cl > SO4 > HCO3 > PO4 > NO3, respectively. Heavy metals occurred in the order Pb > Fe > Cu > Cd in Awka and Fe > Cu > Pb > Cd in Nnewi. Five water types and three water facies dominate Awka metropolis, whereas eight water types and four water facies dominate Nnewi metropolis. The physicochemical parameters for both metropolises are well within quality standards. However, pH of most of the samples is off standard limits, classing the waters as neutral to slightly acidic. Also, the groundwaters are generally contaminated with heavy metals. Pollution index of Awka metropolis (ranging 0.542–73.083) is higher than that of Nnewi metropolis (ranging 0.069–6.617). Further, Pb has the highest contamination factor in Awka metropolis, whereas Cd has the highest in Nnewi metropolis. Based on the gross characteristics observed in both metropolises, the waters are considered unfit for drinking purposes, but could be used for other domestic and industrial purposes which do not require them being used for food processing.