Integrating water quality indices and multivariate statistical techniques for water pollution assessment of the Volta Lake, Ghana

Abstract

The Volta Lake was assessed to characterize the general water quality for sustainable and efficient management. Results show that DO levels in the lake may result in hypoxic conditions if, not monitored. Based on the BOD levels, the Volta Lake could be considered as having received no significant to significant pollution discharges. Nutrient results show that the limiting nutrient in the Volta Lake is P-limiting. The weighted solway index (WQI) assessment shows the fairly good quality characteristics of the lake and its ability to support human and animal use although requiring monitoring. The Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI) assessment also shows that the overall water quality of the lake was fair and therefore, water quality characteristics may be fluctuating between pristine and impaired levels. Additionally, water quality may usually be suitable for the protection of aquatic life but occasionally threatened with conditions departing from natural or desirable levels and therefore, requiring conventional treatment. Based on the classification of the Water Pollution Index (WPIKR), the chemical health status of the lake was fair and therefore, requiring monitoring for ecosystem sustainability. Principal Component Analysis (PCA) resulted in the extraction of five principal components which accounted for approximately 75.45% of the total variance with eigenvalues\u2009>\u20091. PCA also shows expected process-based and hidden relationships amongst factors that generally govern the water chemistry and the major dissolved ions in the lake. This study highlights a possible early warning of ecological/pollution problems in the lake. It is thus, recommended that the Water Resources Commission (WRC) which is the agency responsible for the management of the Volta Lake in Ghana adopts monitoring measures to prevent imminent pollution of the Volta Lake.