Chronic urban hotspots and agricultural drainage drive microbial pollution of karst water resources in rural developing regions

Buckerfield, S. J., Quilliam, R. S., Bussiere, L., Waldron, S. , Naylor, L. A. , Li, S. and Oliver, D. M. (2020) Chronic urban hotspots and agricultural drainage drive microbial pollution of karst water resources in rural developing regions. Science of the Total Environment, 744, 140898. (doi: 10.1016/j.scitotenv.2020.140898) (PMID:32721677)

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Contamination of surface and groundwater systems with human and animal faecal matter leads to exposure of reliant populations to disease causing micro-organisms. This exposure route remains a major cause of infection and mortality in developing countries, particularly rural regions. To meet the UN's sustainable development goal 6: Ensure availability and sustainable management of water and sanitation for all, we need to identify the key controls on faecal contamination across relevant settings. We conducted a high-resolution spatial study of E. coli concentration in catchment drainage waters over 6 months in a mixed land-use catchment in the extensive karst region extending across impoverished southwest China. Using a mixed effects modelling framework, we tested how land-use, karst hydrology, antecedent meteorological conditions, agricultural cycles, hydrochemistry, and position in the catchment system affected E. coli concentrations. Land-use was the best predictor of faecal contamination levels. Sites in urban areas were chronically highly contaminated, but water draining from agricultural land was also consistently contaminated and there was a catchment wide pulse of higher E. coli concentrations, turbidity, and discharge during paddy field drainage. E. coli concentration increased with increasing antecedent rainfall across all land-use types and compartments of the karst hydrological system (underground and surface waters), but decreased with increasing pH. This is interpreted to be a result of processes affecting pH, such as water residence time, rather than the direct effect of pH on E. coli survival. Improved containment and treatment of human waste in areas of higher population density would likely reduce contamination hotspots, and further research is needed to identify the nature and distribution of sources in agricultural land.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Waldron, Professor Susan and Naylor, Dr Larissa
Creator Roles:
Waldron, S.Conceptualization, Funding acquisition, Supervision, Writing – review and editing
Naylor, L. A.Conceptualization, Funding acquisition, Supervision, Writing – review and editing
Authors: Buckerfield, S. J., Quilliam, R. S., Bussiere, L., Waldron, S., Naylor, L. A., Li, S., and Oliver, D. M.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Science of the Total Environment
ISSN (Online):1879-1026
Published Online:16 July 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Science of the Total Environment 744: 140898
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
173283IAPETUS - Using bioprotective buffers to improve coastal infrastructure resilienceLarissa NaylorNatural Environment Research Council (NERC)NE/L002590/1GES - Geography
172384The transmissive critical zone: understanding the karst hydrology-biogeochemical interface for sustainable managementSusan WaldronNatural Environment Research Council (NERC)NE/N007425/1GES - Geography