Water Quality Assessment of Groundwater Using Multivariate Statistical Techniques: A Case Study of Mogadishu, Banadir Region, Somalia

Abstract

This study was carried out to assess the groundwater quality around the Mogadishu area, Banadir region, Somalia. Multivariate statistical techniques such as factor analysis (FA), principal component analysis (PCA) and cluster analysis (CA)were applied to 22 groundwater samples collected from boreholes and dug wells in the coastal line districts namely: Wadajir, Kaxda and Dharkinley districts of Banadir region, Somalia. Correlations among 14 hydrochemical parameters were statistically examined. A two-factor model is suggested and explains over 82.4% of the total groundwater quality variation. Factor Analysis (FA) revealed significant variables including electrical conductivity (EC), pH value and other parameters such as K<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup>, SO<sub>4</sub><sup>2-</sup> and hardness expressed as CaCO<sub>3</sub>, Chlorine, Fluoride, B, S, Si, and NO<sub>3</sub> which are responsible for variations in groundwater quality and affect water chemistry. The results were compared with the World Health Organization (WHO) standard guidelines. Geographic Information System (GIS) was used to create the spatial distribution maps of water quality parameters. Cluster Analysis (CA) grouped all sites into three zones based on spatial similarities and dissimilarities of physiochemical properties. The pH value and Boron, fluoride calcium, magnesium, sulfide, potassium, and Silica are well within the desirable limit at all locations. However, the concentration of conductivity chloride, hardness as CaCO<sub>3</sub>, sulfate, nitrate, and Sodium in all samples exceeded the desirable WHO maximum permissible limit. The study reveals that the groundwater quality changed due to anthropogenic and natural influences such as natural weathering processes. As a result of this the qualities of the boreholes and dug well water samples were therefore not suitable for human consumption without adequate treatment. Regular monitoring of groundwater quality, abolishing unhealthy waste disposal practices, and introducing modern techniques are recommended.