Surface-derived groundwater contamination in Gulu District, Uganda: Chemical and microbial tracers.

Autor: Wilson GJL; Department of Earth and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, United Kingdom., Muloogi D; Department of Earth and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, United Kingdom; Department of Energy, Minerals, and Petroleum Studies, Mbarara University of Science and Technology, P.O Box 1410, Mbarara, Uganda., Hamisi R; KTH-International Groundwater Arsenic Research Group, Department of Sustainable Development, Environmental Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm, Sweden., Denwood T; Mapping, Computing and Geographical Information Science (MCGIS), Department of Geography, The University of Manchester, Arthur Lewis Building, Oxford Road, Manchester M13 9PL, United Kingdom., Bhattacharya P; KTH-International Groundwater Arsenic Research Group, Department of Sustainable Development, Environmental Science and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm, Sweden., Nuwategeka E; Geography Department, Gulu University, Gulu City, Uganda., Gooddy DC; British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB, United Kingdom., Polya DA; Department of Earth and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, United Kingdom., Huck JJ; Mapping, Computing and Geographical Information Science (MCGIS), Department of Geography, The University of Manchester, Arthur Lewis Building, Oxford Road, Manchester M13 9PL, United Kingdom., Richards LA; Department of Earth and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, United Kingdom. Electronic address: laura.richards@manchester.ac.uk.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 Dec 10; Vol. 955, pp. 177118. Date of Electronic Publication: 2024 Oct 22.
DOI: 10.1016/j.scitotenv.2024.177118
Abstrakt: Groundwater is consumed by over 2 billion people globally, though it can be impacted by microbial and chemical contamination in both rural and (peri-)urban areas. This issue is particularly pertinent in regions like East Africa, where rapid urbanisation has strained local infrastructure, including water and sanitation systems. We use selected tracers of human and animal waste to assess the quality of community drinking sources with regards to surface-derived groundwater inputs and to compare urban versus rural water quality, under the rapidly developing urban area of Gulu, Northern Uganda. Specifically, we examine bulk and fluorescent dissolved organic matter (DOM), microorganisms (total coliforms, E. coli) and inorganic tracers of anthropogenic waste (NO 3 - , SO 4 2- , Cl/Br) from various sources: boreholes (12-76 m depth; n = 90), protected springs (n = 11) and municipal taps (n = 4). Our results show that NO 3 - and SO 4 2- were elevated in groundwater sources in the Gulu city urban area and the Cl/Br ratio was elevated in springs, compared to concentrations in the more rural Aswa and Omoro County area (p < 0.05). Interestingly, human and animal waste indicators E. coli and Tryp:FA (the ratio of tryptophan-like to fulvic-like fluorescence) displayed no significant difference between rural and urban settings (p > 0.05), though total coliforms were significantly higher in rural boreholes (p < 0.05). The presence of a pollution source, pollution carrier and a breakdown of a sanitary barrier at the borehole, as spot-checked by a visual sanitary risk assessment, was significantly associated with groundwater E. coli abundances. Evidence suggests monitoring and mitigation should be improved for all water types in Gulu District to meet WHO and Uganda Standard guidelines for potable water. This study offers valuable insights for water management planning and risk assessment of community water sources particularly in the context of East Africa and similar settings.
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 © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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