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Water quality of fresh water bodies in the lower Volta Basin: A case study of lakes Kasu and Nyafie
Abstract
The study was carried out on water from lakes Kasu and Nyafie, two of the fresh water bodies situated near Asutsuare, an agricultural town in the lower Volta basin of Ghana to determine the level of water quality parameters. To be able to this, water samples were taken from designated points in both lakes. Sampling was done over a period of seven months (January to July) and the determination of the water quality parameters was carried out using GEMS Water Operational Guide as well as APHA’s Standard Methods for Examination of Water and Wastewater. The parameters measured were; temperature, pH, dissolve oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), conductivity, turbidity, suspended solids, dissolved solids and total solids. Others were nutrients and ions such as; nitrates, nitrites, phosphates, chlorides, sodium and potassium. The rest came under hardness of water, such as calcium, magnesium and total hardness. Though most of the values of the parameters fall within the acceptable limits of WHO values for potable water, turbidity values i.e. 68.0 NTU (Kasu) and 25.2 NTU (Nyafie) as well as BOD values of 73.8 mg/L for Kasu and 49.7 mg/L for Nyafie, were far beyond the WHO guideline limits (5 NTU – turbidity and < 3 mg/L – BOD) for drinking water, thereby reducing the potability, recreational and aesthetic values of the water in these lakes. Also, despite the fact that the mean DO values for the lakes (5.4 mg/L for Nyafie and 7.0 mg/L for Kasu) fall short of the WHO minimum value of 8.0 mg/L, the lakes cannot be said to be polluted to signal the unset of eutrophication.
Keywords: water quality parameters, runoff water, fresh water bodies