Characterization of groundwater quality in three settlement areas of Enugu metropolis, southeastern Nigeria, using multivariate analysis.

Groundwater quality of Enugu metropolis comprising Achara Layout, Abakpa, and Emene settlement areas has been studied and characterized using multivariate statistical techniques. Three principal components (PCs) which explain 77.93 and 88.17% were extracted at Achara Layout and Abakpa, respectively, while two PCs which explain 83.13% were extracted at Emene. PC 1 of all the three areas reflects weathering of the host rock minerals and constitutes the dominant controlling process for all the areas. PC 2 of the three areas and PC 3 of Achara Layout and Abakpa can be attributed to both weathering/leaching of feldspathic minerals of host rocks (giving rise to alkaline earth metals in the groundwater) and anthropogenic activities. Cluster analysis defined groups of groundwater samples with similar hydrochemical characteristics. Two groups in Achara Layout and Emene fell into the high pollution loading class, while only one group in Abakpa fell into this class. The variation in the groundwater quality within each of the three areas may be explained in terms of groundwater flow directions, land use, and well depths. Discriminant analysis showed that the discriminating parameters of the groundwater quality of Achara Layout, Abakpa, and Emene are total dissolved solids, Na and Mg, and Cl, respectively. This study has revealed that the groundwater quality of the areas is controlled by both geogenic and anthropogenic processes and activities. The generated groundwater quality spatial variation models for each area will serve as a tool in the planning and development of groundwater in that region.