Sorensen, James Peter Robert;
(2022)
Rapid detection of faecally contaminated drinking water with in-situ fluorescence spectroscopy.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Two billion people consume drinking water contaminated with human and animal faeces. The resulting infections are a major source of disease globally, with an estimated 500,000 deaths per year from diarrhoea alone. This thesis explores the viability of in-situ fluorescence spectroscopy as a simpler, instantaneous, more temporally resilient alternative to faecal indicator organisms (FIOs) to indicate faecal contamination risk in drinking water sources across a range of hydrological and climatological settings. TLF was a significant predictor in logistic regression models of the presence-absence of FIOs and moderately to very strongly correlated with FIO enumeration, including in real-time data. HLF was also shown to be a similarly effective indicator to TLF of FIO presence-absence and enumeration. TLF/HLF were superior to other rapid approaches, such as turbidity, sanitary risk scores or total bacterial cell counts, to indicate FIOs. Seasonal sampling demonstrated TLF/HLF were more associated with FIOs during the wet season than dry season. The ranking of sources using TLF/HLF was more resilient with time than that using FIOs, with dry season TLF/HLF more related to wet season FIOs, when FIOs are elevated, then dry season FIOs. In groundwater, tryptophan-like and humic-like fluorophores were shown to be predominantly extracellular and hence will have different transport properties in comparison to FIOs and larger pathogens. Fluorophores were also demonstrated to accumulate in highly contaminated intergranular aquifers where TLF/HLF intensity related to other indicators of faecal contamination, such as on-site sanitation density, but not to FIO enumeration. In-situ fluorescence spectroscopy is a simple, instantaneous approach to screen water sources for faecal contamination risk. The technique offers global scope to reduce population exposure to enteric pathogens in drinking water: from providing real-time data across municipal supply infrastructure to assessing the relative risks between drinking water sources in low-income settings.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Rapid detection of faecally contaminated drinking water with in-situ fluorescence spectroscopy |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL SLASH UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10161287 |
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