Investigating Novel Approaches for Detecting Microbial Contamination in Drinking Water in Africa

Microbial contamination of drinking water causes disease and death worldwide, with low and middle income countries (LMICs) at greatest risk. UN Sustainable Development Goal 6 recognises this, but achieving these targets will be a monumental challenge, especially in sub-Saharan Africa. Monitoring microbial water quality is essential. Traditionally, this has been done by culturing bacterial coliforms, however, lack of resources in LMICs poses barriers to data collection. This research presents novel findings that enhance our understanding of two emerging technologies for assessing microbial drinking water quality; i) in situ tryptophan-like fluorescence (TLF) and ii) high throughput sequencing (HTS) to determine bacterial community composition. Results show that TLF offers a distinct advantage by generating rapid results with few consumables, but is only suitable for high-level screening because the influence of humic-like fluorescence restricts the level of detection for microbial contamination. TLF indicates a broader contamination risk than bacterial coliforms and is not recommended as a substitute; elevated TLF does not always translate to a public health risk as defined by culturing techniques. TLF thresholds are needed for widespread use, but equating TLF thresholds to bacterial coliform data may not be appropriate. HTS directly measures bacterial DNA and therefore generates more specific results than proxy indicators. With the potential for portable HTS on the horizon, this could become important for characterising risks to drinking water. Source type and condition influenced hydrochemical conditions at a source and therefore shaped bacterial community composition. Novel comparison of TLF with bacterial community composition indicated that TLF assesses long-term hydrochemical conditions rather than acute public health risk. Considering practical application and research impact, selecting an appropriate method(s) is always vital. Detecting microbial contamination rapidly, accurately and at low cost would facilitate the development of water quality monitoring worldwide, ultimately leading to public health improvements and, in turn, save lives.