Spatial and temporal variations of faecal indicator bacteria in Lake Bunyonyi, South‑Western Uganda
Background Microbial water quality serves to indicate health risks associated with the consumption of contaminated water. Nevertheless, little is known about the microbiological characteristics of water in Lake Bunyonyi. This study was therefore undertaken to examine the spatial and temporal varia...
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| Main Authors: | , , , |
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| Format: | Article |
| Published: |
SN Applied Sciences
2021
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.12493/509 |
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| Summary: | Background Microbial water quality serves to indicate health risks associated with the consumption of contaminated
water. Nevertheless, little is known about the microbiological characteristics of water in Lake Bunyonyi. This study was
therefore undertaken to examine the spatial and temporal variations of faecal indicator bacteria (FIB) in relation to
physicochemical parameters in Lake Bunyonyi. Result The FIB concentration was consistently measured during sampling
months and correlated with each other showing the presumed human faecal pollution in the lake. The highest concentration
values for E. coli (64.7 ± 47.3 CFU/100 mL) and enterococci (24.6 ± 32.4 CFU/100 mL were obtained in the station
close to the Mugyera trading centre. On a temporal basis, the maximum values were recorded during the rainy season
in October 2019 (70.7 ± 56.5 CFU/100 mL for E. coli and 38.44 ± 31.8 CFU/100 mL for enterococci. FIB did not differ significantly
among the study stations (p > 0.05) but showed significant temporal variations among the months (p < 0.05) with
concentrations being significantly high in wet season than dry season (U = 794, p < 0.0001 for E. coli; U = 993.5, p = 0.008
for enterococci). Spearman’s rank correlation revealed that FIB concentrations were significantly positively correlated with
turbidity and DO concentration levels (p < 0.05). Approximately 97.2% of the water samples had E. coli and enterococci
concentrations levels below USEPA threshold for recreational waters. Likewise, 98.1 and 90.7% of samples recorded E.
coli and enterococci counts exceeding the UNBS, APHA, WHO and EU threshold values for drinking water. Conclusion
The FIB counts show that the Lake Bunyonyi water is bacteriologically unsuitable for drinking unless it is treated since
the FIB pose health risks to consumers. Besides, the water can be used for recreational purposes. |
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