Temporal Variation of Eutrophication Assessment of Lake Bosomtwe, Ghana

Abstract

Bosomtwe Lake is a freshwater lake in the Ashanti Region of Ghana, and is the habitat for many native plant and animal species. It is also a place for tourism and, therefore, the water quality and health status of the lake are vital for conservation of species and tourism. The main objective of this study was to examine the water quality of the lake in relation to nutrient load and possible eutrophication of the lake. It also explored the correlation between some physico-chemical parameters of the lake to inform policy direction on a watershed management strategy of the lake. A total of 40 samples were taken from different parts on the lake for analysis. This was done during the wet and dry seasons in 2012 and 2013. The results showed a general lower concentration of these parameters in the wet season and a higher concentration in the dry season.  The statistical results also indicated a negative correlation between Total Nitrogen and Total Phosphorus (r = -0.839, p = 0.075), Total Nitrogen and Total Dissolved Solid  (r = -0.771, p = 0.125), Total Nitrogen and Dissolved Oxygen (r = -0.749, p = 0.145) and Total Nitrogen and pH (r = -0.754, p = 0.141). However, Total Phosphorus showed a positive correlation with Total Dissolved Solid (r = 0.670, p = 0.216), Dissolved Oxygen  (r = 0.830, p = 0.085), pH (r = 0.546, p = 0.314) and Temperature (r = 0.427, p = 474). The nutrient load on the lake water though low, it has the potential to increase the eutrophication of the lake if not controlled and this will be dangerous for ecological entities within the catchment. The association between TP and TDS should be closely monitored since there was a strong positive correlation between them.  The major setback of this study was unavailability of the facilities to analyse colour, turbidity, faecal coliform, Escherichia coli count, chlorophyll-a, and algal growth in the lake.

DOI: http://dx.doi.org/10.5755/j01.erem.72.1.13976