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Tytuł:
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Large-scale survey of seasonal drinking water quality in Malawi using in situ tryptophan-like fluorescence and conventional water quality indicators.
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Autorzy:
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Ward JST; British Geological Survey, Keyworth, Nottinghamshire NG12 5GG, UK; UK Centre for Ecology & Hydrology, Wallingford OX10 8BB, UK; Department of Civil and Environmental Engineering, University of Surrey, Guildford, GU2 7XH, UK. Electronic address: .
Lapworth DJ; British Geological Survey, Wallingford, OX10 8BB, UK.
Read DS; UK Centre for Ecology & Hydrology, Wallingford OX10 8BB, UK.
Pedley S; Department of Civil and Environmental Engineering, University of Surrey, Guildford, GU2 7XH, UK.
Banda ST; University of Malawi, Chancellor College, Zomba, Malawi.
Monjerezi M; University of Malawi, Chancellor College, Zomba, Malawi.
Gwengweya G; University of Malawi, Chancellor College, Zomba, Malawi.
MacDonald AM; British Geological Survey, Lyell Centre, Edinburgh EH14 4AP, UK.
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Źródło:
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The Science of the total environment [Sci Total Environ] 2020 Nov 20; Vol. 744, pp. 140674. Date of Electronic Publication: 2020 Jul 02.
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Typ publikacji:
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Journal Article
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Język:
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English
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Imprint Name(s):
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Original Publication: Amsterdam, Elsevier.
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MeSH Terms:
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Drinking Water*
Environmental Monitoring ; Humans ; Malawi ; Seasons ; Surveys and Questionnaires ; Tryptophan ; Water Microbiology ; Water Quality ; Water Supply
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Contributed Indexing:
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Keywords: Drinking water; Groundwater quality; Humic-like fluorescence (HLF); Microbial contamination; Rapid screening; Risk assessment
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Substance Nomenclature:
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0 (Drinking Water)
8DUH1N11BX (Tryptophan)
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Entry Date(s):
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Date Created: 20200807 Date Completed: 20200916 Latest Revision: 20200916
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Update Code:
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20240105
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DOI:
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10.1016/j.scitotenv.2020.140674
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PMID:
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32755770
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Faecally-contaminated drinking water is a risk to human health, with the greatest risks to those living in developing countries. UN Sustainable Development Goal 6 aims to address this issue. Tryptophan-like fluorescence (TLF) shows potential as a rapid method for detecting microbial contamination in drinking water, which could reduce the spread of waterborne diseases. This study is the first to investigate the effectiveness of TLF for a large-scale survey using a randomised, spot-sampling approach. The large-scale survey took place in Malawi, sub-Saharan Africa, in the dry season (n = 183). A subset of sources were revisited at the end of the following wet season (n = 41). The effectiveness of TLF was assessed by comparing TLF results to thermotolerant coliforms (TTC), humic-like fluorescence (HLF), inorganic hydrochemical data and sanitary risk scores. The most prominent differences in microbial water quality were observed between source types, with little variation between districts and seasons. TLF, TTCs, turbidity and sanitary risk scores were all elevated at alternative sources (shallow wells and tap stands) compared to hand-pumped boreholes. In the dry season, 18% of hand-pumped boreholes showed TTC contamination, which increase to 21% in the wet season. Groundwater recharge processes are likely responsible for seasonal variability of inorganic hydrochemistry at hand-pumped boreholes. TLF was able to distinguish no and low WHO risk classes (TTC 0-9 cfu/100 mL) from medium, high and very high risk classes (TTC 10 - >1000 cfu/100 mL). TLF failed to distinguish between no and low risk classes, which limits the use of TLF for assessing water quality to drinking water standards. This dataset indicates that HLF may raise baseline TLF for samples with low TLF values, increasing false positives. Therefore, TLF is better suited as a rapid high-level water quality screening tool to assess moderate and high levels of faecal contamination.
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. Published by Elsevier B.V.)
