Principal component analysis of groundwater quality data underlying Geochemical processes of Dahomeyan formation and Togo series in the Ho Municipality (Ghana)

Abstract

The physico-chemical quality data of groundwater extracted from 36 boreholes in Ho Municipality indicated that 11 sources recorded pH values outside WHO guideline range, while 5 recorded turbidity levels above WHO guideline limits. Sodium levels ranged from 1.80 to 544 mg/L with a mean of 111 ± 132 mg/l; chloride level ranged from 2.98 to 898 mg/L with a mean of 124 ± 183 mg/L, and cation and anion dominance was in the ord-er Na+ > Mg 2+ > Ca 2+ > K + and HCO 3 - > Cl - > SO 4 2- respectively. The quality data was subjected to Principal Component Analysis, and two components (PC1 and PC2) were extracted. The PC1 represented nearly 88.17 % of the variance and had high absolute loadings for electrical conductivity, calcium, alkalinity and chloride, indi-cating interactions of minerals from the Dahomeyan formation and Togo series with the groundwater in the area. The PC2 accounted for 6.62 % of total variance, showing high loadings for colour, turbidity, HCO 3 and total iron. The major geochemical processes taking place might be the presence and dissolution of carbonates and dolomites, evaporated minerals and chemical reactions involving reverse ion-exchange in the aquifer