Pub Date : 2024-04-04DOI: 10.1371/journal.pwat.0000143
B. Desta, Johanna Sanchez, Cole Heasley, Ian Young, J. Tustin
At many public beaches, routine monitoring of beach water quality using fecal indicator bacteria is conducted to evaluate the risk of recreational water illness. Results from water sample analysis can take over 24-hr, which may no longer accurately reflect current water quality conditions. This study aimed to assess which combination of environmental factors best predicts fecal contamination (E. coli) levels at two of the most popular beaches on Lake Winnipeg, Manitoba (Gimli and Grand Beach), by linking water quality data and publicly available environmental data from 2007 to 2021. We developed separate mixed effects models for each beach for two outcomes, linear (continuous log-transformed E. coli concentration) and categorical (200 CFU/100 ml threshold), to explore differences in the predictors of E. coli concentrations and exceedances of the provincial health risk threshold, respectively. We used a Directed Acyclic Graph to choose which predictor variables to include in the models. For both beaches, we identified clustering of the E. coli outcomes by year, suggesting year-specific variation. We also determined that extreme weather days, with higher levels of rainfall in the preceding 48-hr, previous day average air temperature, and previous day E. coli concentration could result in a higher probability of E. coli threshold exceedances or higher concentrations in the water bodies. In Grand Beach, we identified that days with lower average UV levels in the previous 24-hr and antecedent dry days could result in a higher probability of E. coli threshold exceedances or higher concentrations. The findings can inform possible trends in other freshwater settings and be used to help develop real-time recreational water quality predictive models to allow more accurate beach management decisions and warrant enhancement of beach monitoring programs for extreme weather events as part of the climate change preparedness efforts.
许多公共海滩都会使用粪便指示细菌对海滩水质进行例行监测，以评估娱乐用水患病的风险。水样分析结果可能需要 24 小时以上的时间，这可能不再能准确反映当前的水质状况。本研究旨在通过将 2007 年至 2021 年的水质数据和公开环境数据联系起来，评估哪种环境因素组合最能预测马尼托巴省温尼伯湖两个最受欢迎的海滩（Gimli 和 Grand Beach）的粪便污染（大肠杆菌）水平。我们为每个海滩分别建立了线性（连续对数变换的大肠杆菌浓度）和分类（200 CFU/100 ml 阈值）两种结果的混合效应模型，以分别探索大肠杆菌浓度和超过省健康风险阈值的预测因素的差异。我们使用有向无环图（Directed Acyclic Graph）来选择将哪些预测变量纳入模型。对于这两个海滩，我们按年份确定了大肠埃希氏菌结果的聚类，这表明了特定年份的变化。我们还确定，极端天气日（前 48 小时降雨量、前一天平均气温和前一天大肠埃希氏菌浓度较高）可能导致水体中大肠埃希氏菌阈值超标或浓度较高。在大海滩，我们发现前 24 小时平均紫外线水平较低的日子和前一天干燥的日子会导致大肠杆菌阈值超标或浓度升高的概率较高。这些发现可以为其他淡水环境中可能出现的趋势提供信息，并可用于帮助开发实时娱乐水质预测模型，从而做出更准确的海滩管理决策，并确保加强海滩监测计划，以应对极端天气事件，作为气候变化准备工作的一部分。
{"title":"Environmental factors associated with Escherichia coli concentration at freshwater beaches on Lake Winnipeg, Manitoba, Canada","authors":"B. Desta, Johanna Sanchez, Cole Heasley, Ian Young, J. Tustin","doi":"10.1371/journal.pwat.0000143","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000143","url":null,"abstract":"At many public beaches, routine monitoring of beach water quality using fecal indicator bacteria is conducted to evaluate the risk of recreational water illness. Results from water sample analysis can take over 24-hr, which may no longer accurately reflect current water quality conditions. This study aimed to assess which combination of environmental factors best predicts fecal contamination (E. coli) levels at two of the most popular beaches on Lake Winnipeg, Manitoba (Gimli and Grand Beach), by linking water quality data and publicly available environmental data from 2007 to 2021. We developed separate mixed effects models for each beach for two outcomes, linear (continuous log-transformed E. coli concentration) and categorical (200 CFU/100 ml threshold), to explore differences in the predictors of E. coli concentrations and exceedances of the provincial health risk threshold, respectively. We used a Directed Acyclic Graph to choose which predictor variables to include in the models. For both beaches, we identified clustering of the E. coli outcomes by year, suggesting year-specific variation. We also determined that extreme weather days, with higher levels of rainfall in the preceding 48-hr, previous day average air temperature, and previous day E. coli concentration could result in a higher probability of E. coli threshold exceedances or higher concentrations in the water bodies. In Grand Beach, we identified that days with lower average UV levels in the previous 24-hr and antecedent dry days could result in a higher probability of E. coli threshold exceedances or higher concentrations. The findings can inform possible trends in other freshwater settings and be used to help develop real-time recreational water quality predictive models to allow more accurate beach management decisions and warrant enhancement of beach monitoring programs for extreme weather events as part of the climate change preparedness efforts.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"12 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140741732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-04DOI: 10.1371/journal.pwat.0000187
G. Clayton, R. Thorn, B. Fox, Darren M. Reynolds
Two billion people lack access to safely managed drinking water services, many of these are in low/middle income countries where centralised systems are impractical. Decentralised point-of-use drinking water treatment systems offer alternative solutions in remote or resource constrained settings. The main aim of this study was to assess the long-term (3 year) operation and performance of a point-of-use drinking water treatment system (POU-DWTS). A biologically contaminated urban drainage pond was used as a water source and the quality of the produced drinking water was assessed over two independent trials. The decentralised POU-DWTS combined ultrafiltration membranes with disinfection from electrochemically generated hypochlorous acid (HOCl). The operational parameters, such as flow rate, free available chlorine and transmembrane pressure, were monitored in real-time and recorded via a remote monitoring system. Water quality from the source and treated water was assessed over two trial periods within the 3-year operational trial: an 11-week period at the start and a 22-week trial at the end. All water samples were assessed for a range of basic, chemical, microbiological and metal water quality parameters. The results demonstrate that the decentralised POU-DWTS is capable of continuously producing high quality drinking water when HOCl is continuously used to dose water prior to entering the ultrafiltration [UF] membranes. Over the 3-year operational study, the continuous dosing of HOCl pre-UF membranes resulted in stable permeability, indicating no occurrences of irreversible biofouling within the UF membranes and that good membrane ‘health’ was maintained throughout. As such, there was no need to replace the UF membranes nor undertake acid/alkaline chemical cleans at any point throughput the three-year study. The POU-DWTS continuously produced high quality drinking water, resulting in 6453 m3 of drinking water produced over the trial period, that met international water quality standards, at a community scale within the location studied.
{"title":"Long-term trial of a community-scale decentralized point-of-use drinking water treatment system","authors":"G. Clayton, R. Thorn, B. Fox, Darren M. Reynolds","doi":"10.1371/journal.pwat.0000187","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000187","url":null,"abstract":"Two billion people lack access to safely managed drinking water services, many of these are in low/middle income countries where centralised systems are impractical. Decentralised point-of-use drinking water treatment systems offer alternative solutions in remote or resource constrained settings. The main aim of this study was to assess the long-term (3 year) operation and performance of a point-of-use drinking water treatment system (POU-DWTS). A biologically contaminated urban drainage pond was used as a water source and the quality of the produced drinking water was assessed over two independent trials. The decentralised POU-DWTS combined ultrafiltration membranes with disinfection from electrochemically generated hypochlorous acid (HOCl). The operational parameters, such as flow rate, free available chlorine and transmembrane pressure, were monitored in real-time and recorded via a remote monitoring system. Water quality from the source and treated water was assessed over two trial periods within the 3-year operational trial: an 11-week period at the start and a 22-week trial at the end. All water samples were assessed for a range of basic, chemical, microbiological and metal water quality parameters. The results demonstrate that the decentralised POU-DWTS is capable of continuously producing high quality drinking water when HOCl is continuously used to dose water prior to entering the ultrafiltration [UF] membranes. Over the 3-year operational study, the continuous dosing of HOCl pre-UF membranes resulted in stable permeability, indicating no occurrences of irreversible biofouling within the UF membranes and that good membrane ‘health’ was maintained throughout. As such, there was no need to replace the UF membranes nor undertake acid/alkaline chemical cleans at any point throughput the three-year study. The POU-DWTS continuously produced high quality drinking water, resulting in 6453 m3 of drinking water produced over the trial period, that met international water quality standards, at a community scale within the location studied.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"18 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140741366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-02DOI: 10.1371/journal.pwat.0000191
Brendan J. Moran, D. Boutt, L. A. Munk, Joshua D. Fisher
Deciphering the dominant controls on the connections between groundwater, surface water, and climate is critical to understanding water cycles in arid environments. Yet, persistent uncertainties in the fundamental hydrology of these systems remain. The growing demand for critical minerals such as lithium and associated water demands in the arid environments in which they often occur has amplified the urgency to address these uncertainties. We present an integrated hydrological analysis of the Dry Andes region utilizing a uniquely comprehensive set of tracer data (3H, 18O/2H) for these environments, paired directly with physical hydrological observations. We find two strongly decoupled hydrological systems that interact only under specific hydrogeological conditions where preferential conduits exist. The primary conditions creating these conduits are laterally extensive fine-grained evaporite and/or lacustrine units and perennial flowing streams connected with regional groundwater discharge sites. The efficient capture and transport of modern or “contemporary” water (weeks to years old) within these conduits is the primary control of the interplay between modern hydroclimate variations and groundwater aquifers in these environments. Modern waters account for a small portion of basin budgets but are critical to sustaining surface waters due to the existence of these conduits. As a result, surface waters near basin floors are disproportionally sensitive to short-term climate and anthropogenic perturbations. The framework we present describes a new understanding of the dominant controls on natural water cycles intrinsic to these arid high-elevation systems that will improve our ability to manage critical water resources.
{"title":"Contemporary and relic waters strongly decoupled in arid alpine environments","authors":"Brendan J. Moran, D. Boutt, L. A. Munk, Joshua D. Fisher","doi":"10.1371/journal.pwat.0000191","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000191","url":null,"abstract":"Deciphering the dominant controls on the connections between groundwater, surface water, and climate is critical to understanding water cycles in arid environments. Yet, persistent uncertainties in the fundamental hydrology of these systems remain. The growing demand for critical minerals such as lithium and associated water demands in the arid environments in which they often occur has amplified the urgency to address these uncertainties. We present an integrated hydrological analysis of the Dry Andes region utilizing a uniquely comprehensive set of tracer data (3H, 18O/2H) for these environments, paired directly with physical hydrological observations. We find two strongly decoupled hydrological systems that interact only under specific hydrogeological conditions where preferential conduits exist. The primary conditions creating these conduits are laterally extensive fine-grained evaporite and/or lacustrine units and perennial flowing streams connected with regional groundwater discharge sites. The efficient capture and transport of modern or “contemporary” water (weeks to years old) within these conduits is the primary control of the interplay between modern hydroclimate variations and groundwater aquifers in these environments. Modern waters account for a small portion of basin budgets but are critical to sustaining surface waters due to the existence of these conduits. As a result, surface waters near basin floors are disproportionally sensitive to short-term climate and anthropogenic perturbations. The framework we present describes a new understanding of the dominant controls on natural water cycles intrinsic to these arid high-elevation systems that will improve our ability to manage critical water resources.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"220 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140751340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-02DOI: 10.1371/journal.pwat.0000188
Alyssa Schubert, Jacob Harrison, Linda Kent-Buchanan, Victor Bonds, S. Hughes, Shawn P. McElmurry, Matthew Seeger, N. Love
Understanding water users’ perceptions of drinking water quality and the water service provider are important to understand for effective communication with users. Traditionally, the primary means through which water users receive information about drinking water is via the annual Consumer Confidence Report, which summarizes water quality information at the water system-scale and not at the point-of-use. In this study, we recruited 24 water users from different homes in Detroit, Michigan to assess the effect of access to individualized data on perceptions related to their drinking water quality and service provider. Each participant had a water quality sensor node, which measured five different water quality parameters, temporarily installed in their home for four weeks. Entry interviews were completed at the time of sensor node installation. After four weeks, water quality reports summarizing the individual water quality data collected by the sensor nodes were prepared and shared with participants, after which the exit interviews were completed. We found that access to individualized water quality data positively affected participants’ perceptions of drinking water quality and safety, for example, 92% of participants rated the safety of water at the faucet as at least ‘Somewhat Safe’ in the exit interview compared to 46% in the entry interview. However, participants’ perceptions of the water service provider did not change significantly in response to this information (p > 0.05). Half of the study participants expressed interest in more frequent monitoring and communication, including actionable data that allowed participants to make more informed decisions about how to better manage their water quality at home. We saw evidence of long-term changes in response to access to individualized information with 50% reporting changes in behavior related to drinking water use. We conclude that access to localized water quality data provides actionable information that Detroit, Michigan water users value.
{"title":"Perceptions of drinking water: Understanding the role of individualized water quality data in Detroit, Michigan","authors":"Alyssa Schubert, Jacob Harrison, Linda Kent-Buchanan, Victor Bonds, S. Hughes, Shawn P. McElmurry, Matthew Seeger, N. Love","doi":"10.1371/journal.pwat.0000188","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000188","url":null,"abstract":"Understanding water users’ perceptions of drinking water quality and the water service provider are important to understand for effective communication with users. Traditionally, the primary means through which water users receive information about drinking water is via the annual Consumer Confidence Report, which summarizes water quality information at the water system-scale and not at the point-of-use. In this study, we recruited 24 water users from different homes in Detroit, Michigan to assess the effect of access to individualized data on perceptions related to their drinking water quality and service provider. Each participant had a water quality sensor node, which measured five different water quality parameters, temporarily installed in their home for four weeks. Entry interviews were completed at the time of sensor node installation. After four weeks, water quality reports summarizing the individual water quality data collected by the sensor nodes were prepared and shared with participants, after which the exit interviews were completed. We found that access to individualized water quality data positively affected participants’ perceptions of drinking water quality and safety, for example, 92% of participants rated the safety of water at the faucet as at least ‘Somewhat Safe’ in the exit interview compared to 46% in the entry interview. However, participants’ perceptions of the water service provider did not change significantly in response to this information (p > 0.05). Half of the study participants expressed interest in more frequent monitoring and communication, including actionable data that allowed participants to make more informed decisions about how to better manage their water quality at home. We saw evidence of long-term changes in response to access to individualized information with 50% reporting changes in behavior related to drinking water use. We conclude that access to localized water quality data provides actionable information that Detroit, Michigan water users value.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"79 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140752884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-13DOI: 10.1371/journal.pwat.0000184
Kelley Moyers, J. Abatzoglou, A. Escriva-Bou, J. Medellín-Azuara, J. Viers
California’s bountiful San Joaquin Valley (SJV), a critical region for global fruit and nut production, has withstood two severe, multi-year droughts in the past decade, exacerbated by record-breaking high temperature and evaporative demand. We employed climate data and crop coefficients to estimate the crop water demand in the SJV over the past forty years. Our approach, using crop coefficients for Penman-Montieth modeled evapotranspiration, focused on the climate effects on crop water demand, avoiding the confounding factors of changing land use and management practices that are present in actual evapotranspiration. We demonstrate that increases in crop water demand explain half of the cumulative deficits of the agricultural water balance since 1980, exacerbating water reliance on depleting groundwater supplies and fluctuating surface water imports. We call this phenomenon of climate-induced increased crop water demand an invisible water surcharge. We found that in the past decade, this invisible water surcharge on agriculture has increased the crop water demand in the SJV by 4.4% with respect to the 1980–2011 timeframe—more than 800 GL per year, a volume as large as a major reservoir in the SJV. Despite potential agronomic adaptation and crop response to climate warming, increased crop water demand adds a stressor to the sustainability of the global fruit and nut supply and calls for changes in management and policies to consider the shifting hydroclimate.
{"title":"An invisible water surcharge: Climate warming increases crop water demand in the San Joaquin Valley’s groundwater-dependent irrigated agriculture","authors":"Kelley Moyers, J. Abatzoglou, A. Escriva-Bou, J. Medellín-Azuara, J. Viers","doi":"10.1371/journal.pwat.0000184","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000184","url":null,"abstract":"California’s bountiful San Joaquin Valley (SJV), a critical region for global fruit and nut production, has withstood two severe, multi-year droughts in the past decade, exacerbated by record-breaking high temperature and evaporative demand. We employed climate data and crop coefficients to estimate the crop water demand in the SJV over the past forty years. Our approach, using crop coefficients for Penman-Montieth modeled evapotranspiration, focused on the climate effects on crop water demand, avoiding the confounding factors of changing land use and management practices that are present in actual evapotranspiration. We demonstrate that increases in crop water demand explain half of the cumulative deficits of the agricultural water balance since 1980, exacerbating water reliance on depleting groundwater supplies and fluctuating surface water imports. We call this phenomenon of climate-induced increased crop water demand an invisible water surcharge. We found that in the past decade, this invisible water surcharge on agriculture has increased the crop water demand in the SJV by 4.4% with respect to the 1980–2011 timeframe—more than 800 GL per year, a volume as large as a major reservoir in the SJV. Despite potential agronomic adaptation and crop response to climate warming, increased crop water demand adds a stressor to the sustainability of the global fruit and nut supply and calls for changes in management and policies to consider the shifting hydroclimate.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140245886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-06DOI: 10.1371/journal.pwat.0000210
B. Malla, Kazuki Yamamoto, Kotomi Furukawa, E. Haramoto
Microbial source tracking (MST) using host-specific Bacteroidales and mitochondrial DNA (mtDNA) markers is an efficient tool to identify the sources of fecal contamination in environmental water. This study evaluated and updated the previously reported performances of seven host-specific Bacteroidales markers (three human-, two cattle-, and two pig-specific). Additionally, the performance of a cattle-specific Bovine mtDNA and a pig-specific Swine mtDNA marker were evaluated and then applied to MST of river water samples collected in Yamanashi Prefecture, Japan. We collected 48 fecal-source samples, including raw sewage, secondary-treated sewage, an effluent of a domestic wastewater treatment tank, pig feces, pig wastewater, and cattle feces, which were quantitatively analyzed using host-specific Bacteroidales and mtDNA markers. BacHum and gyrB markers (human-specific), BacR and Bovine mtDNA markers (cattle-specific), and Pig2Bac and Swine mtDNA markers (pig-specific) were judged the best-performing markers. Then, these selected markers were applied to MST to identify the sources of fecal contamination in 59 river water samples collected at 21 sites. Of them, 20 (95%), 21 (100%), and 16 (76%) sites were positive for at least one human, cattle, and pig marker, respectively, indicating the need for immediate action and monitoring to control fecal pollution.
{"title":"Performance evaluation and application of host-specific Bacteroidales and mitochondrial DNA markers to identify sources of fecal contamination in river water in Japan","authors":"B. Malla, Kazuki Yamamoto, Kotomi Furukawa, E. Haramoto","doi":"10.1371/journal.pwat.0000210","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000210","url":null,"abstract":"Microbial source tracking (MST) using host-specific Bacteroidales and mitochondrial DNA (mtDNA) markers is an efficient tool to identify the sources of fecal contamination in environmental water. This study evaluated and updated the previously reported performances of seven host-specific Bacteroidales markers (three human-, two cattle-, and two pig-specific). Additionally, the performance of a cattle-specific Bovine mtDNA and a pig-specific Swine mtDNA marker were evaluated and then applied to MST of river water samples collected in Yamanashi Prefecture, Japan. We collected 48 fecal-source samples, including raw sewage, secondary-treated sewage, an effluent of a domestic wastewater treatment tank, pig feces, pig wastewater, and cattle feces, which were quantitatively analyzed using host-specific Bacteroidales and mtDNA markers. BacHum and gyrB markers (human-specific), BacR and Bovine mtDNA markers (cattle-specific), and Pig2Bac and Swine mtDNA markers (pig-specific) were judged the best-performing markers. Then, these selected markers were applied to MST to identify the sources of fecal contamination in 59 river water samples collected at 21 sites. Of them, 20 (95%), 21 (100%), and 16 (76%) sites were positive for at least one human, cattle, and pig marker, respectively, indicating the need for immediate action and monitoring to control fecal pollution.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"5 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140262329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-06DOI: 10.1371/journal.pwat.0000228
David A. Chin
Conventional designs of infiltration swales either neglect infiltration while the swale is filling or approximate the flow in the swale as being normal instead of gradually varied. The adequacy of these approximations are elucidated, and two common design configurations for infiltration swales are considered. For swales designed to store the water-quality volume behind check dams, the retained volume can be on the order of twice the design water-quality volume depending on the magnitude of the inflow rate normalized by the infiltration rate. In a second configuration, the swale is designed to infiltrate the water-quality flow, where the limiting assumption is that the flow is normal along the infiltration length. The actual required infiltration length can be expressed as a function of the normalized bottom width, and the required infiltration length can be up to 30% longer than derived using the conventional design. Graphical relations are developed that can be used to either quantify the factor of safety of conventional designs or provide credit for in the flood-control function of infiltration swales.
{"title":"Design of infiltration swales","authors":"David A. Chin","doi":"10.1371/journal.pwat.0000228","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000228","url":null,"abstract":"Conventional designs of infiltration swales either neglect infiltration while the swale is filling or approximate the flow in the swale as being normal instead of gradually varied. The adequacy of these approximations are elucidated, and two common design configurations for infiltration swales are considered. For swales designed to store the water-quality volume behind check dams, the retained volume can be on the order of twice the design water-quality volume depending on the magnitude of the inflow rate normalized by the infiltration rate. In a second configuration, the swale is designed to infiltrate the water-quality flow, where the limiting assumption is that the flow is normal along the infiltration length. The actual required infiltration length can be expressed as a function of the normalized bottom width, and the required infiltration length can be up to 30% longer than derived using the conventional design. Graphical relations are developed that can be used to either quantify the factor of safety of conventional designs or provide credit for in the flood-control function of infiltration swales.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"14 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140263088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-05DOI: 10.1371/journal.pwat.0000230
Claire McDonald, Kara Cunningham, Grace Kerr, Belle Lu, M. H. Tarek, Christopher Anderson, Emily Garner
Multiple threats to surface water quality, including both fecal pollution and acid mine drainage (AMD) are frequently coincident in mining regions, such as parts of the Appalachian region of the U.S. While it has been established that AMD can have toxic effects to fecal bacteria in surface waters, there is also evidence that AMD may induce a viable but non-culturable (VBNC) state, leaving fecal bacteria undetectable by common standard methods. This study aims to better understand the occurrence of VBNC Escherichia coli in mining-impacted waters (MIW) through three objectives: (1) assess the relationship between MIWs and concentrations of culturable fecal bacteria, (2) compare standard methods for quantification of E. coli in MIW, and (3) investigate whether MIW can induce a VBNC state in E. coli. An analysis of historic data from the Deckers Creek and West Run Watersheds of West Virginia revealed a moderate correlation between pH and E. coli abundance determined via culture and enzyme-based methods. In samples collected from sites within the two watersheds impacted by historic mining activities, the E. coli uidA gene was measured via quantitative polymerase chain reaction (qPCR) and found to be significantly more abundant than E. coli concentrations measured via culture or enzyme substrate coliform test. However, this discrepancy between methods was greatest in samples with a low pH. Further, experiments in which an environmental strain of E. coli was dosed into samples of MIW diluted with saline at different concentrations confirmed that the culturability of E. coli significantly decreased with increasing MIW concentration, while the total number of intact cells, determined via "live/dead” staining and microscopy, remained high. This finding suggests that culture and enzyme methods may underestimate viable E. coli levels in AMD-impacted waters.
{"title":"Assessing viability of Escherichia coli in mining-impacted surface waters","authors":"Claire McDonald, Kara Cunningham, Grace Kerr, Belle Lu, M. H. Tarek, Christopher Anderson, Emily Garner","doi":"10.1371/journal.pwat.0000230","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000230","url":null,"abstract":"Multiple threats to surface water quality, including both fecal pollution and acid mine drainage (AMD) are frequently coincident in mining regions, such as parts of the Appalachian region of the U.S. While it has been established that AMD can have toxic effects to fecal bacteria in surface waters, there is also evidence that AMD may induce a viable but non-culturable (VBNC) state, leaving fecal bacteria undetectable by common standard methods. This study aims to better understand the occurrence of VBNC Escherichia coli in mining-impacted waters (MIW) through three objectives: (1) assess the relationship between MIWs and concentrations of culturable fecal bacteria, (2) compare standard methods for quantification of E. coli in MIW, and (3) investigate whether MIW can induce a VBNC state in E. coli. An analysis of historic data from the Deckers Creek and West Run Watersheds of West Virginia revealed a moderate correlation between pH and E. coli abundance determined via culture and enzyme-based methods. In samples collected from sites within the two watersheds impacted by historic mining activities, the E. coli uidA gene was measured via quantitative polymerase chain reaction (qPCR) and found to be significantly more abundant than E. coli concentrations measured via culture or enzyme substrate coliform test. However, this discrepancy between methods was greatest in samples with a low pH. Further, experiments in which an environmental strain of E. coli was dosed into samples of MIW diluted with saline at different concentrations confirmed that the culturability of E. coli significantly decreased with increasing MIW concentration, while the total number of intact cells, determined via \"live/dead” staining and microscopy, remained high. This finding suggests that culture and enzyme methods may underestimate viable E. coli levels in AMD-impacted waters.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"110 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140079205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-05DOI: 10.1371/journal.pwat.0000217
Lauren D’Mello-Guyett, Camille Heylen, Elsa Rohm, Jane Falconer, Jean Lapegue, R. Dreibelbis, Monica Ramos, Oliver Cumming, Daniele Lantagne
Water, sanitation and hygiene (WASH) interventions should provide access to safe water and sanitation, and promote good hygiene practices with dignity, comfort and security. Multiple systematic reviews have noted evidence gaps and is a paucity of good quality evidence related to the effectiveness and implementation of WASH programmes and interventions in humanitarian crises. The aim of this study was to generate consensus-based actionable research priorities for the humanitarian WASH sector. A research prioritisation exercise was conducted by adapting the Child Health and Nutrition Research Initiative (CHNRI) method. Research questions were compiled from a rapid scoping review, key informant interviews (KIIs) and focus group discussions (FGDs). Questions were reviewed by a technical expert group. An online survey was circulated to score research questions according to five criteria. An overall prioritisation score was calculated and weighted to prioritise questions. A diverse range of 286 global WASH and health experts engaged in the CHNRI process. A list of 128 questions were generated and scored by experts. Prioritised research questions focussed on evaluating existing interventions or programmes, and making iterative changes to current programmes. Other important questions centred on describing WASH conditions and associated health risks in crises contexts. Priorities were also stratified by gender, organisation and region to understand differences globally. The WASH in Crises Research Agenda has identified key research questions of most importance to those implementing WASH in humanitarian crises and has established a list of research priorities. The identified priorities reinforce how more evidence is needed, and underlines the need for research to evaluate current practices in order to improve the quality of humanitarian response. Stakeholders, including donors, international and national organisations, governments and academic institutions, are invited to use this research agenda to encourage, inspire and enable relevant and high-quality research that will be used to inform humanitarian responses.
{"title":"Research priorities for water, sanitation and hygiene (WASH) in humanitarian crises: A global prioritisation exercise","authors":"Lauren D’Mello-Guyett, Camille Heylen, Elsa Rohm, Jane Falconer, Jean Lapegue, R. Dreibelbis, Monica Ramos, Oliver Cumming, Daniele Lantagne","doi":"10.1371/journal.pwat.0000217","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000217","url":null,"abstract":"Water, sanitation and hygiene (WASH) interventions should provide access to safe water and sanitation, and promote good hygiene practices with dignity, comfort and security. Multiple systematic reviews have noted evidence gaps and is a paucity of good quality evidence related to the effectiveness and implementation of WASH programmes and interventions in humanitarian crises. The aim of this study was to generate consensus-based actionable research priorities for the humanitarian WASH sector. A research prioritisation exercise was conducted by adapting the Child Health and Nutrition Research Initiative (CHNRI) method. Research questions were compiled from a rapid scoping review, key informant interviews (KIIs) and focus group discussions (FGDs). Questions were reviewed by a technical expert group. An online survey was circulated to score research questions according to five criteria. An overall prioritisation score was calculated and weighted to prioritise questions. A diverse range of 286 global WASH and health experts engaged in the CHNRI process. A list of 128 questions were generated and scored by experts. Prioritised research questions focussed on evaluating existing interventions or programmes, and making iterative changes to current programmes. Other important questions centred on describing WASH conditions and associated health risks in crises contexts. Priorities were also stratified by gender, organisation and region to understand differences globally. The WASH in Crises Research Agenda has identified key research questions of most importance to those implementing WASH in humanitarian crises and has established a list of research priorities. The identified priorities reinforce how more evidence is needed, and underlines the need for research to evaluate current practices in order to improve the quality of humanitarian response. Stakeholders, including donors, international and national organisations, governments and academic institutions, are invited to use this research agenda to encourage, inspire and enable relevant and high-quality research that will be used to inform humanitarian responses.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"38 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-04DOI: 10.1371/journal.pwat.0000227
J. Unrine, Nina McCoy, W. J. Christian, Yogesh Gautam, L. Ormsbee, Wayne Sanderson, Ricki Draper, Madison Mooney, Mary Cromer, Kelly Pennell, A. G. Hoover
To increase our understanding of the factors that influence formation of disinfection byproducts (DBPs) in rural drinking systems, we investigated the spatial and seasonal variation in trihalomethane (THM) and haloacetic acid (HAA) concentrations in relation to various chemical and physical variables in a rural public drinking water system in Martin County, Kentucky, USA. We collected drinking water samples from 97 individual homes over the course of one year and analyzed them for temperature, electrical conductivity, pH, free chlorine, total chlorine, THMs (chloroform, bromodichloromethane, dibromochloromethane, dichlorobromomethane, and bromoform) and HAAs (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, and dibromoacetic acid). Spatial autocorrelation analysis showed only weak overall clustering for HAA concentrations and none for THMs. The relationship between modeled water age and TTHM or HAA5 concentrations varied seasonally. In contrast, there was strong variation for both HAA and THMs, with concentrations of HAA peaking in mid-summer and THMs peaking in early fall. Multiple regression analysis revealed that THM concentrations were strongly correlated with conductivity, while HAA concentrations were more strongly correlated with water temperature. Individual DBP species that only contained chlorine halogen groups were strongly correlated with temperature, while compounds containing bromine were more strongly correlated with conductivity. Further investigation revealed that increased drinking water conductivity associated with low discharge of the Tug Fork River, the source water, is highly correlated with increased concentrations of bromide. Discharge and conductivity of the Tug Fork River changed dramatically through the year contributing to a seasonal peak in bromide concentrations in the late summer and early fall and appeared to be a driver of brominated THM concentrations. Brominated DBPs tend to have higher toxicity than DBPs containing only chlorine, therefore this study provides important insight into the seasonal factors driving risk from exposure to DBPs in rural drinking water systems impacted by bromide.
{"title":"Spatial and seasonal variation in disinfection byproducts concentrations in a rural public drinking water system: A case study of Martin County, Kentucky, USA","authors":"J. Unrine, Nina McCoy, W. J. Christian, Yogesh Gautam, L. Ormsbee, Wayne Sanderson, Ricki Draper, Madison Mooney, Mary Cromer, Kelly Pennell, A. G. Hoover","doi":"10.1371/journal.pwat.0000227","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000227","url":null,"abstract":"To increase our understanding of the factors that influence formation of disinfection byproducts (DBPs) in rural drinking systems, we investigated the spatial and seasonal variation in trihalomethane (THM) and haloacetic acid (HAA) concentrations in relation to various chemical and physical variables in a rural public drinking water system in Martin County, Kentucky, USA. We collected drinking water samples from 97 individual homes over the course of one year and analyzed them for temperature, electrical conductivity, pH, free chlorine, total chlorine, THMs (chloroform, bromodichloromethane, dibromochloromethane, dichlorobromomethane, and bromoform) and HAAs (monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, and dibromoacetic acid). Spatial autocorrelation analysis showed only weak overall clustering for HAA concentrations and none for THMs. The relationship between modeled water age and TTHM or HAA5 concentrations varied seasonally. In contrast, there was strong variation for both HAA and THMs, with concentrations of HAA peaking in mid-summer and THMs peaking in early fall. Multiple regression analysis revealed that THM concentrations were strongly correlated with conductivity, while HAA concentrations were more strongly correlated with water temperature. Individual DBP species that only contained chlorine halogen groups were strongly correlated with temperature, while compounds containing bromine were more strongly correlated with conductivity. Further investigation revealed that increased drinking water conductivity associated with low discharge of the Tug Fork River, the source water, is highly correlated with increased concentrations of bromide. Discharge and conductivity of the Tug Fork River changed dramatically through the year contributing to a seasonal peak in bromide concentrations in the late summer and early fall and appeared to be a driver of brominated THM concentrations. Brominated DBPs tend to have higher toxicity than DBPs containing only chlorine, therefore this study provides important insight into the seasonal factors driving risk from exposure to DBPs in rural drinking water systems impacted by bromide.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"30 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140265911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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