In-situ fluorescence spectroscopy indicates total bacterial abundance and dissolved organic carbon.

Autor: Sorensen JPR; British Geological Survey, Maclean Building, Wallingford OX10 8BB, UK; Department of Geography, University College London, London WC1E 6BT, UK. Electronic address: jare1@bgs.ac.uk., Diaw MT; Department of Geology, Université Cheikh Anta Diop, Senegal., Pouye A; Department of Geology, Université Cheikh Anta Diop, Senegal., Roffo R; Department of Geography, University College London, London WC1E 6BT, UK., Diongue DML; Department of Geology, Université Cheikh Anta Diop, Senegal., Faye SC; Department of Geology, Université Cheikh Anta Diop, Senegal., Gaye CB; Department of Geology, Université Cheikh Anta Diop, Senegal., Fox BG; Centre for Research in Biosciences, University of the West of England, Bristol BS16 1QY, UK., Goodall T; UK Centre for Ecology & Hydrology (UKCEH), Maclean Building, Wallingford OX10 8BB, UK., Lapworth DJ; British Geological Survey, Maclean Building, Wallingford OX10 8BB, UK., MacDonald AM; British Geological Survey, Lyell Centre, Research Avenue South, Edinburgh EH14 4AP, UK., Read DS; UK Centre for Ecology & Hydrology (UKCEH), Maclean Building, Wallingford OX10 8BB, UK., Ciric L; Department of Civil, Environmental & Geomatic Engineering, University College London, London WC1E 6BT, UK., Taylor RG; Department of Geography, University College London, London WC1E 6BT, UK.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2020 Oct 10; Vol. 738, pp. 139419. Date of Electronic Publication: 2020 May 19.
DOI: 10.1016/j.scitotenv.2020.139419
Abstrakt: We explore in-situ fluorescence spectroscopy as an instantaneous indicator of total bacterial abundance and faecal contamination in drinking water. Eighty-four samples were collected outside of the recharge season from groundwater-derived water sources in Dakar, Senegal. Samples were analysed for tryptophan-like (TLF) and humic-like (HLF) fluorescence in-situ, total bacterial cells by flow cytometry, and potential indicators of faecal contamination such as thermotolerant coliforms (TTCs), nitrate, and in a subset of 22 samples, dissolved organic carbon (DOC). Significant single-predictor linear regression models demonstrated that total bacterial cells were the most effective predictor of TLF, followed by on-site sanitation density; TTCs were not a significant predictor. An optimum multiple-predictor model of TLF incorporated total bacterial cells, nitrate, nitrite, on-site sanitation density, and sulphate (r 2 0.68). HLF was similarly related to the same parameters as TLF, with total bacterial cells being the best correlated (ρ s 0.64). In the subset of 22 sources, DOC clustered with TLF, HLF, and total bacterial cells, and a linear regression model demonstrated HLF was the best predictor of DOC (r 2 0.84). The intergranular nature of the aquifer, timing of the study, and/or non-uniqueness of the signal to TTCs can explain the significant associations between TLF/HLF and indicators of faecal contamination such as on-site sanitation density and nutrients but not TTCs. The bacterial population that relates to TLF/HLF is likely to be a subsurface community that develops in-situ based on the availability of organic matter originating from faecal sources. In-situ fluorescence spectroscopy instantly indicates a drinking water source is impacted by faecal contamination but it remains unclear how that relates specifically to microbial risk in this setting.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 United Kingdom Research and Innovation, as represented by its component body, the British Geological Survey. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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