Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR
Abstract In the basin of Mekong, over 70 million people rely on unimproved surface water for their domestic requirements. Surface water is often contaminated with fecal matter and yet little information exists on the underlying mechanisms of fecal contamination in tropical conditions at large waters...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2021-02-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-021-82891-0 |
| _version_ | 1830297161066086400 |
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| author | Paty Nakhle Olivier Ribolzi Laurie Boithias Sayaphet Rattanavong Yves Auda Saysongkham Sayavong Rosalie Zimmermann Bounsamay Soulileuth Anne Pando Chanthamousone Thammahacksa Emma J. Rochelle-Newall William Santini Jean-Michel Martinez Nicolas Gratiot Alain Pierret |
| author_facet | Paty Nakhle Olivier Ribolzi Laurie Boithias Sayaphet Rattanavong Yves Auda Saysongkham Sayavong Rosalie Zimmermann Bounsamay Soulileuth Anne Pando Chanthamousone Thammahacksa Emma J. Rochelle-Newall William Santini Jean-Michel Martinez Nicolas Gratiot Alain Pierret |
| author_sort | Paty Nakhle |
| collection | DOAJ |
| description | Abstract In the basin of Mekong, over 70 million people rely on unimproved surface water for their domestic requirements. Surface water is often contaminated with fecal matter and yet little information exists on the underlying mechanisms of fecal contamination in tropical conditions at large watershed scales. Our objectives were to (1) investigate the seasonality of fecal contamination using Escherichia coli as fecal indicator bacteria (FIB), and (2) establish links between the fecal contamination in stream water and its controlling factors (hydrology and land use). We present the results of (1) a sampling campaign at the outlet of 19 catchments across Lao PDR, in both the dry and the rainy seasons of 2016, and (2) a 10-day interval monitoring conducted in 2017 and 2018 at three point locations of three rivers (Nam Ou, Nam Suang, and Mekong) in northern Lao PDR. Our results show the presence of fecal contamination at most of the sampled sites, with a seasonality characterized by higher and extreme E. coli concentrations occurring during the rainy season. The highest E. coli concentrations, strongly correlated with total suspended sediment concentrations, were measured in catchments dominated by unstocked forest areas, especially in mountainous northern Lao PDR and in Vientiane province. |
| first_indexed | 2024-12-19T07:28:13Z |
| format | Article |
| id | doaj.art-bcc8721562294313b125c8e53c463268 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-19T07:28:13Z |
| publishDate | 2021-02-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-bcc8721562294313b125c8e53c4632682022-12-21T20:30:47ZengNature PortfolioScientific Reports2045-23222021-02-0111111710.1038/s41598-021-82891-0Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDRPaty Nakhle0Olivier Ribolzi1Laurie Boithias2Sayaphet Rattanavong3Yves Auda4Saysongkham Sayavong5Rosalie Zimmermann6Bounsamay Soulileuth7Anne Pando8Chanthamousone Thammahacksa9Emma J. Rochelle-Newall10William Santini11Jean-Michel Martinez12Nicolas Gratiot13Alain Pierret14Géosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPSGéosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPSGéosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPSLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot HospitalGéosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPSLao Department of Agriculture Land Management (DALaM), Ministry of Agriculture and ForestryLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot HospitalInstitut de Recherche Pour le Développement (IRD), iEES-Paris, UMR 242 (IRD, SU-UPMC, CNRS, INRA, Univ. de Paris, UPEC)Institut de Recherche Pour le Développement (IRD), iEES-Paris, UMR 242 (IRD, SU-UPMC, CNRS, INRA, Univ. de Paris, UPEC)Institut de Recherche Pour le Développement (IRD), iEES-Paris, UMR 242 (IRD, SU-UPMC, CNRS, INRA, Univ. de Paris, UPEC)Institute of Ecology and Environmental Sciences of Paris (iEES-Paris), Sorbonne Université, Univ Paris Est Creteil, IRD, CNRS, INRAGéosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPSGéosciences Environnement Toulouse (GET), Université de Toulouse, CNRS, IRD, UPSUniv. Grenoble Alpes, CNRS, IRD, Grenoble INP, IGEInstitut de Recherche Pour le Développement (IRD), iEES-Paris, UMR 242 (IRD, SU-UPMC, CNRS, INRA, Univ. de Paris, UPEC)Abstract In the basin of Mekong, over 70 million people rely on unimproved surface water for their domestic requirements. Surface water is often contaminated with fecal matter and yet little information exists on the underlying mechanisms of fecal contamination in tropical conditions at large watershed scales. Our objectives were to (1) investigate the seasonality of fecal contamination using Escherichia coli as fecal indicator bacteria (FIB), and (2) establish links between the fecal contamination in stream water and its controlling factors (hydrology and land use). We present the results of (1) a sampling campaign at the outlet of 19 catchments across Lao PDR, in both the dry and the rainy seasons of 2016, and (2) a 10-day interval monitoring conducted in 2017 and 2018 at three point locations of three rivers (Nam Ou, Nam Suang, and Mekong) in northern Lao PDR. Our results show the presence of fecal contamination at most of the sampled sites, with a seasonality characterized by higher and extreme E. coli concentrations occurring during the rainy season. The highest E. coli concentrations, strongly correlated with total suspended sediment concentrations, were measured in catchments dominated by unstocked forest areas, especially in mountainous northern Lao PDR and in Vientiane province.https://doi.org/10.1038/s41598-021-82891-0 |
| spellingShingle | Paty Nakhle Olivier Ribolzi Laurie Boithias Sayaphet Rattanavong Yves Auda Saysongkham Sayavong Rosalie Zimmermann Bounsamay Soulileuth Anne Pando Chanthamousone Thammahacksa Emma J. Rochelle-Newall William Santini Jean-Michel Martinez Nicolas Gratiot Alain Pierret Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR Scientific Reports |
| title | Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR |
| title_full | Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR |
| title_fullStr | Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR |
| title_full_unstemmed | Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR |
| title_short | Effects of hydrological regime and land use on in-stream Escherichia coli concentration in the Mekong basin, Lao PDR |
| title_sort | effects of hydrological regime and land use on in stream escherichia coli concentration in the mekong basin lao pdr |
| url | https://doi.org/10.1038/s41598-021-82891-0 |
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