Evaluation of <fc>O</fc>wabi <fc>R</fc>eservoir (<fc>G</fc>hana) water quality using factor analysis: Fid-Bau Portal

Evaluation of Owabi Reservoir (Ghana) water quality using factor analysis

Akoto, Osei / Abankwa, Ernest

The Owabi Reservoir receives water inflows from several streams that drain through the rapidly urbanizing towns in the Kumasi metropolis. The reservoir catchment had been encroached upon by various human activities, resulting in the generation of large volumes of waste water being discharged into streams draining to the reservoir. This study presents a comprehensive evaluation of the water quality of Owabi Reservoir. Water samples from 10 sampling sites within the reservoir were analysed for various water quality parameters; namely, pH, electrical conductivity (EC), sulphate ( ${SO}_{4}^{2 -}$ ), phosphate ( ${PO}_{4}^{3 -}$ ), chloride (Cl⁻), lead (Pb), arsenic (As), zinc (Zn), iron (Fe), copper (Cu), total dissolved solids (TSS), turbidity, faecal coliform and E. coli. The measured water quality parameters were compared to the guidelines proposed by the WHO for drinking water and natural background levels. Mean values for Pb, As, turbidity, TDS, faecal coliform and E. coli were greater than the WHO guidelines. Factor analysis for the measured parameters resulted in the extraction of five factors accounting for 83.13% of the total variance. Factor 1 showed strong loadings for ${PO}_{4}^{3 -}$ , ${SO}_{4}^{2 -}$ and TDS, reflecting a negative influence on the water quality by agricultural discharges. Factor 2 showed high loadings for EC, Cl⁻ and apparent colour, while Factor 3 registered high loadings for colour and faecal coliform, suggesting domestic wastewater discharges and the presence of decaying organic matter. Factors 4 and 5 showed high loadings for copper, lead, turbidity and E. coli, an indication of both organic and inorganic pollution. Accordingly, periodic monitoring of Owabi Reservoir water quality, and the streams draining into it, is recommended as a means of ensuring good water quality, as well as facilitating the identification of the possible types and sources of water pollutants entering the reservoir.