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Vucinic L, O'Connell D, Coxon C, Gill L. Back to the future: Comparing yeast as an outmoded artificial tracer for simulating microbial transport in karst aquifer systems to more modern approaches. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 349:123942. [PMID: 38604303 DOI: 10.1016/j.envpol.2024.123942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/19/2024] [Accepted: 04/07/2024] [Indexed: 04/13/2024]
Abstract
Bacterial contamination of karst groundwater is a major concern for public health. Artificial tracing studies are crucial for establishing links between locations where pollutants can rapidly reach the aquifer systems and subsequent receptors, as well as for enhanced understanding of pollutant transport. However, widely used solute artificial tracers do not always move through the subsurface in the same manner as particles and microorganisms, hence may not be ideal proxies for predicting movement of bacterial contaminants. This study evaluates whether a historically used microbial tracer (yeast) which is readily available, inexpensive, and environmentally friendly, but usually overlooked in modern karst hydrogeological studies due to challenges associated with its detection and quantification in the past, can reemerge as a valuable tracer using the latest technology for its detection. Two field-based studies on separate karst systems were carried out during low-flow conditions using a portable particle counter along with flow cytometry measurements to monitor the recovery of the yeast at the springs. Soluble fluorescent dyes were also injected simultaneously with the yeast for comparison of transport dynamics. On one tracer test, through a karst conduit of much higher velocities, the injected yeast and fluorescent dye arrived at the same time at the spring, in comparison to the tracer test on a conduit system with lower groundwater velocities in which the yeast particles were detected before the dye at the sampling site. Both a portable particle counter and flow cytometry successfully detected yeast during both tests, thereby demonstrating the applicability of this tracer with contemporary instrumentation. Even though no significant advantages of flow cytometry over the portable counter system can be reported on the basis of the presented results, this study has shown that flow cytometry can be successfully used to detect and quantify introduced microbial tracers in karst environments with extremely high precision.
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Affiliation(s)
- Luka Vucinic
- Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, the University of Dublin, Ireland.
| | - David O'Connell
- Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, the University of Dublin, Ireland
| | - Catherine Coxon
- Department of Geology, Trinity College Dublin, the University of Dublin, Ireland; Trinity Centre for the Environment, Trinity College Dublin, the University of Dublin, Ireland
| | - Laurence Gill
- Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, the University of Dublin, Ireland
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Wang Y, Yuan S, Shi J, Ma T, Xie X, Deng Y, Du Y, Gan Y, Guo Z, Dong Y, Zheng C, Jiang G. Groundwater Quality and Health: Making the Invisible Visible. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5125-5136. [PMID: 36877892 DOI: 10.1021/acs.est.2c08061] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Linking groundwater quality to health will make the invisible groundwater visible, but there are knowledge gaps to understand the linkage which requires cross-disciplinary convergent research. The substances in groundwater that are critical to health can be classified into five types according to the sources and characteristics: geogenic substances, biogenic elements, anthropogenic contaminants, emerging contaminants, and pathogens. The most intriguing questions are related to quantitative assessment of human health and ecological risks of exposure to the critical substances via natural or induced artificial groundwater discharge: What is the list of critical substances released from discharging groundwater, and what are the pathways of the receptors' exposure to the critical substances? How to quantify the flux of critical substances during groundwater discharge? What procedures can we follow to assess human health and ecological risks of groundwater discharge? Answering these questions is fundamental for humans to deal with the challenges of water security and health risks related to groundwater quality. This perspective provides recent progresses, knowledge gaps, and future trends in understanding the linkage between groundwater quality and health.
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Affiliation(s)
- Yanxin Wang
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Songhu Yuan
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Jianbo Shi
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Teng Ma
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Xianjun Xie
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Yamin Deng
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Yao Du
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Yiqun Gan
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Zhilin Guo
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yiran Dong
- State Key Laboratory of Biogeology and Environmental Geology, State Environmental Protection Key Laboratory of Water Pollution Source Apportionment and Control, School of Environmental Studies, China University of Geosciences, 430078 Wuhan, P. R. China
| | - Chunmiao Zheng
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Gill LW, Schuler P, Duran L, Morrissey P, Johnston PM. An evaluation of semidistributed-pipe-network and distributed-finite-difference models to simulate karst systems. HYDROGEOLOGY JOURNAL 2020; 29:259-279. [PMID: 33603565 PMCID: PMC7870641 DOI: 10.1007/s10040-020-02241-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/08/2020] [Indexed: 06/12/2023]
Abstract
Several different approaches have been developed to model the specific characteristics of karst aquifers, taking account of their inherent complex spatial and temporal heterogeneities. This paper sets out the development of a semidistributed modelling approach for applications in an Irish karst context using urban drainage software. The models have proven to be very useful for different studies, with examples given for the ecohydrology of ephemeral karst lakes, extreme groundwater-flood alleviation, karst network investigation, submarine groundwater discharge, and quantification of different recharge and flow components. The limitations of the approach are also highlighted, in particular not being able to simulate diffuse infiltration and flow paths explicitly across the groundwater catchment. Hence, a more distributed, finite-difference modelling approach using MODFLOW Unstructured Grid (USG) with the newly developed Connected Linear Network (CLN) process is then compared against the semidistributed approach on the same karst catchment. Whilst it has proven difficult to achieve the same levels of model performance in simulating the spring flows in the distributed model compared to the semidistributed model, the ability to interrogate the flow paths at any point on the three-dimensional aquifer is demonstrated, which can give new insights into flows (and potential contaminant transport) through such complex systems. The influence of the proximity of highly transmissive conduits on the flow dynamics through the much-lower transmissive matrix cells in which the network is embedded has been particularly investigated.
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Affiliation(s)
- L. W. Gill
- Department of Civil, Structural and Environmental Engineering, University of Dublin Trinity College, Dublin 2, Ireland
| | - P. Schuler
- Department of Civil, Structural and Environmental Engineering, University of Dublin Trinity College, Dublin 2, Ireland
| | - L. Duran
- Department of Civil, Structural and Environmental Engineering, University of Dublin Trinity College, Dublin 2, Ireland
| | - P. Morrissey
- Department of Civil, Structural and Environmental Engineering, University of Dublin Trinity College, Dublin 2, Ireland
| | - P. M. Johnston
- Department of Civil, Structural and Environmental Engineering, University of Dublin Trinity College, Dublin 2, Ireland
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