Seasonal analysis of bacteriological quality of drinking water sources in communities surrounding Lake Bosomtwe in the Ashanti Region of Ghana

The 26 communities surrounding the rim of the largest Crater Lake in Africa, the Lake Bosomtwe, depend on the lake for livelihood support. Water sources such as lake, streams and boreholes used as drinking water sources were collected quarterly for a period of 2 years. These were analysed bacteriologically for the determination of total and faecal coliform, Escherichia coli, Aeromonas sp., Enterococcus sp., Salmonella sp., Pseudomonas sp. and total heterotrophic bacteria (THB) using membrane filtration and pour plate techniques. The seasonal variations of these bacteria in the water sources were determined. The results showed variation of bacteria counts in all the water sources. The highest E. coli counts of 2.9 × 103 cfu/100 ml were recorded in the lake and the least in the borehole 2.1 × 101 cfu/100 ml. The difference between the total coliform, faecal coliform and E. coli counts and the water sources was significant (p < 0.05). All the bacteria count with the exception of THB, in the different water sources, had higher bacteria counts during the dry season than the wet season which are statistically significant (p < 0.05). The bacteria contamination of these water sources renders them bacteriologically not suitable for drinking purposes; therefore, drinking these waters without any form of treatments could pose health risk to consumers. These water sources can, however, be used for domestic purposes.