Groundwater microbial quality and risk evaluation in a rapidly transforming urbanized area of Northern Ghana

Abstract

Tamale’s position as a rapidly transforming area presents some merits and challenges including spatial developments and rising demand for safe water respectively. Groundwater remains a primary source of drinking water in many low-resource settings; however, its safety is often compromised by microbial contamination. This study assessed groundwater microbial quality, sanitary characteristics and E. coli infection risk amidst rising urbanisation in the metropolis. Using cluster and purposive sampling, different suburbs and 20 groundwater sites were selected for water sampling and sanitary inspection. Descriptive (median and interquartile range) and inferential statistics (binomial regression, standard t-test, Mann-Whitney U test) were applied to present an overview of the microbial load and risk levels respectively. The study results showed median levels for dug- well water as follows: turbidity 78 (9.75–114) NTU; total coliforms 372 (0-15500) cfu; faecal coliform 11 (0-640) cfu; E. coli 0 (0–50) cfu. Regarding boreholes, turbidity recorded 119 (80–148) NTU; total coliforms 6 E + 02 (0–72 E + 02) cfu; faecal coliform 0 (0-200) cfu; E. coli (0-300) cfu. The prevalence of coliforms, multiple risk factors and unsafe turbidity levels confirmed the poor sanitary and unhygienic practices that characterized the majority of the water sources. E. coli infection risk was associated with dug-wells with none recorded against boreholes. In conclusion, the study findings indicated that tested water sources were microbially contaminated and posed a potential infection risk; therefore periodic disinfection and proper maintenance of aprons, covers and auxiliary components of dug- wells and boreholes are recommended.