title: In-situ tryptophan-like fluorescence: A real-time indicator of faecal contamination in drinking water supplies.
abstract: Enteric pathogens are typically inferred from the presence of surrogate indicator organisms such as thermotolerant (faecal) coliforms (TTCs). The analysis of TTCs requires time-consuming incubation in suitable laboratories, which can limit sampling resolution, particularly during critical pollution events. Here, we demonstrate the use of in-situ fluorimeters targeting tryptophan-like compounds as a rapid, reagentless indicator of TTCs in groundwater-derived potable water supplies in Africa. A range of other common indicators of TTCs were also determined including nitrate, turbidity, and sanitary risk survey scores. Sampling was conducted during both the dry and wet seasons to investigate seasonality. Tryptophan-like fluorescence was the most effective predictor of both presence/absence and number of TTCs during both seasons. Seasonal changes in tryptophan-like fluorescence in deeper supplies suggest it is transported more efficiently through the aquifer than TTCs. Moreover, the perennial elevated concentrations in some wells suggest it is more resilient than TTCs in groundwater. Therefore tryptophan-like fluorescence could also be a better indicator of some smaller, more easily transported, and long-lived, pathogenic enteric viruses. These sensors have the potential to be included in real-time pollution alert systems for drinking water supplies throughout the world, as well as for mapping enteric pathogen risks in developing regions.
authors.affiliation: British Geological Survey, Maclean Building, Wallingford, OX10 8BB, UK. Electronic address: jare1@bgs.ac.uk.
authors.forename: J P R
authors.initials: JP
authors.lastname: Sorensen
authors.affiliation: British Geological Survey, Maclean Building, Wallingford, OX10 8BB, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Lapworth
authors.affiliation: British Geological Survey, Nicker Hill, Keyworth, Nottingham, NG12 5GG, UK.
authors.forename: B P
authors.initials: BP
authors.lastname: Marchant
authors.affiliation: University of Zambia, Great East Road Campus, P.O. Box 32379, Lusaka, Zambia.
authors.forename: D C W
authors.initials: DC
authors.lastname: Nkhuwa
authors.affiliation: Robens Centre for Public and Environmental Health, University of Surrey, Guildford, GU2 7XH, UK.
authors.forename: S
authors.initials: S
authors.lastname: Pedley
authors.affiliation: British Geological Survey, Maclean Building, Wallingford, OX10 8BB, UK.
authors.forename: M E
authors.initials: ME
authors.lastname: Stuart
authors.affiliation: British Geological Survey, Nicker Hill, Keyworth, Nottingham, NG12 5GG, UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Bell
authors.affiliation: University of Zambia, Great East Road Campus, P.O. Box 32379, Lusaka, Zambia.
authors.forename: M
authors.initials: M
authors.lastname: Chirwa
authors.affiliation: University of Zambia, Great East Road Campus, P.O. Box 32379, Lusaka, Zambia.
authors.forename: J
authors.initials: J
authors.lastname: Kabika
authors.affiliation: Lukanga Water and Sewerage Company Limited, P.O. Box 81745, Kabwe, Zambia.
authors.forename: M
authors.initials: M
authors.lastname: Liemisa
authors.affiliation: Lukanga Water and Sewerage Company Limited, P.O. Box 81745, Kabwe, Zambia.
authors.forename: M
authors.initials: M
authors.lastname: Chibesa
mesh_terms: D060766:Drinking Water / Q000032:analysis* / Q000382:microbiology; D004784:Environmental Monitoring / Q000379:methods*; D060587:Groundwater / Q000032:analysis / Q000382:microbiology; D009566:Nitrates / Q000032:analysis; D012621:Seasons; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000032:analysis*; D014871:Water Microbiology; D015024:Zambia
chemical_list: D060766:Drinking Water; D009566:Nitrates; D014364:Tryptophan
keywords: Africa; Fluorescence spectrophotometry; Pathogens; Thermotolerant coliforms; Tryptophan-like; Waste water