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

Autor: Buckerfield SJ; Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom. Electronic address: sarah.buckerfield1@stir.ac.uk., Quilliam RS; Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom., Bussiere L; Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom., Waldron S; School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Naylor LA; School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom., Li S; Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China., Oliver DM; Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, United Kingdom.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2020 Nov 20; Vol. 744, pp. 140898. Date of Electronic Publication: 2020 Jul 16.
DOI: 10.1016/j.scitotenv.2020.140898
Abstrakt: 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.
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.)
Databáze: MEDLINE
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