Pub Date : 2023-10-27DOI: 10.1371/journal.pwat.0000177
Emma T. Brentjens, Elizabeth A. K. Beall, Robert M. Zucker
M . aeruginosa fluorescent changes were observed using a Cytek Aurora spectral flow cytometer that contains 5 lasers and 64 narrow band detectors located between 365 and 829 nm. Cyanobacteria were treated with different concentrations of H 2 O 2 and then monitored after exposure between 1 and 8 days. The red fluorescence emission derived from the excitation of cyanobacteria with a yellow green laser (550 nm) was measured in the 652–669 nm detector while green fluorescence from excitation with a violet laser (405 nm) was measured in the 532–550 nm detector. The changes in these parameters were measured after the addition of H 2 O 2 . There was an initial increase in red fluorescence intensity at 24 hours. This was followed by a daily decrease in red fluorescence intensity. In contrast, green fluorescence increased at 24 hours and remained higher than the control for the duration of the 8-day study. A similar fluorescence intensity effect as H 2 O 2 on M . aeruginosa fluorescence emissions was observed after exposure to acetylacetone, diuron (DCMU), peracetic acid, and tryptoline. Minimal growth was also observed in H 2 O 2 treated cyanobacteria during exposure of H 2 O 2 for 24 days. In another experiment, H 2 O 2 -treated cyanobacteria were exposed to high-intensity blue (14 mW) and UV (1 mW) lights to assess the effects of light stress on fluorescence emissions. The combination of blue and UV light with H 2 O 2 had a synergistic effect on M . aeruginosa that induced greater fluorescent differences between control and treated samples than exposure to either stimulus individually. These experiments suggest that the early increase in red and green fluorescence may be due to an inhibition in the ability of photosynthesis to process photons. Further research into the mechanisms driving these increases in fluorescence is necessary.
{"title":"Analysis of Microcystis aeruginosa physiology by spectral flow cytometry: Impact of chemical and light exposure","authors":"Emma T. Brentjens, Elizabeth A. K. Beall, Robert M. Zucker","doi":"10.1371/journal.pwat.0000177","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000177","url":null,"abstract":"M . aeruginosa fluorescent changes were observed using a Cytek Aurora spectral flow cytometer that contains 5 lasers and 64 narrow band detectors located between 365 and 829 nm. Cyanobacteria were treated with different concentrations of H 2 O 2 and then monitored after exposure between 1 and 8 days. The red fluorescence emission derived from the excitation of cyanobacteria with a yellow green laser (550 nm) was measured in the 652–669 nm detector while green fluorescence from excitation with a violet laser (405 nm) was measured in the 532–550 nm detector. The changes in these parameters were measured after the addition of H 2 O 2 . There was an initial increase in red fluorescence intensity at 24 hours. This was followed by a daily decrease in red fluorescence intensity. In contrast, green fluorescence increased at 24 hours and remained higher than the control for the duration of the 8-day study. A similar fluorescence intensity effect as H 2 O 2 on M . aeruginosa fluorescence emissions was observed after exposure to acetylacetone, diuron (DCMU), peracetic acid, and tryptoline. Minimal growth was also observed in H 2 O 2 treated cyanobacteria during exposure of H 2 O 2 for 24 days. In another experiment, H 2 O 2 -treated cyanobacteria were exposed to high-intensity blue (14 mW) and UV (1 mW) lights to assess the effects of light stress on fluorescence emissions. The combination of blue and UV light with H 2 O 2 had a synergistic effect on M . aeruginosa that induced greater fluorescent differences between control and treated samples than exposure to either stimulus individually. These experiments suggest that the early increase in red and green fluorescence may be due to an inhibition in the ability of photosynthesis to process photons. Further research into the mechanisms driving these increases in fluorescence is necessary.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"82 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136263271","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 : 2023-10-25DOI: 10.1371/journal.pwat.0000053
Jasmine Kelly, Mamonjisoa Tsilahatsy, Tolotra Carnot, Ramanantsiadiana Wilmin Fidelos, Giona Randriamanampy, Andrianarivelo Zafindrazana Charlier, Emilie Kowalczewski, Lomba Hasoavana, Mamy Andriatsihosena, Harry Chaplin, Hugo Legge
In settings where communities rely on unimproved water sources, household rainwater harvesting (HRWH) may improve the quality and quantity of water available. This research presents results from a two-year controlled before-and-after study that evaluated the impact of low-cost HRWH on household water collection habits, hygiene practices and prevalence of childhood diarrhoea in rural Madagascar. The study assessed system functionality, water quality and the acceptability of requesting household financial investment (16–20 USD). Surveys were administered to enrolled intervention households (n = 138) and control households (n = 276) at baseline and endline. Water quality tests at endline compared microbial contamination in a sub-sample of HRWH systems (n = 22) and public water sources (n = 8). Difference-in-difference analyses were used to compare changes in outcomes between study arms at baseline and endline. At endline 111 (75%) of systems were functional with an average age of 1.25 years. Microbial contamination was 39.3 TTC/100ml in community water sources compared with 23.3 TTC/100ml in the HRWH systems (coef: -16.0, 95CI: -37.3 to 5.2, p = 0.133). 85 (57%) of households completed their repayment plans while remaining households owed on average 3.7 USD. There was weak evidence to suggest that intervention households collected more water per capita day than controls (adj coefficient: 3.45; 95CI: -2.51 to 9.41, p = 0.257). Intervention households had 11% higher absolute risk of owning a handwashing station compared against controls (95CI: 0.00 to 0.23; p = 0.06). There was no evidence of differences in ownership of soap or prevalence of childhood diarrhoea between study arms. Overall, operation and maintenance of the systems remained high, users demonstrated willingness to pay, and there was weak evidence that water provision at the household increased domestic consumption. However, the systems did not provide contaminant-free water. We conclude that HRWH using low-cost, locally available materials can increase household access to water in areas reliant on limited communal water sources.
{"title":"Low-cost domestic rainwater harvesting in rural southeast Madagascar: A process and outcome evaluation","authors":"Jasmine Kelly, Mamonjisoa Tsilahatsy, Tolotra Carnot, Ramanantsiadiana Wilmin Fidelos, Giona Randriamanampy, Andrianarivelo Zafindrazana Charlier, Emilie Kowalczewski, Lomba Hasoavana, Mamy Andriatsihosena, Harry Chaplin, Hugo Legge","doi":"10.1371/journal.pwat.0000053","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000053","url":null,"abstract":"In settings where communities rely on unimproved water sources, household rainwater harvesting (HRWH) may improve the quality and quantity of water available. This research presents results from a two-year controlled before-and-after study that evaluated the impact of low-cost HRWH on household water collection habits, hygiene practices and prevalence of childhood diarrhoea in rural Madagascar. The study assessed system functionality, water quality and the acceptability of requesting household financial investment (16–20 USD). Surveys were administered to enrolled intervention households (n = 138) and control households (n = 276) at baseline and endline. Water quality tests at endline compared microbial contamination in a sub-sample of HRWH systems (n = 22) and public water sources (n = 8). Difference-in-difference analyses were used to compare changes in outcomes between study arms at baseline and endline. At endline 111 (75%) of systems were functional with an average age of 1.25 years. Microbial contamination was 39.3 TTC/100ml in community water sources compared with 23.3 TTC/100ml in the HRWH systems (coef: -16.0, 95CI: -37.3 to 5.2, p = 0.133). 85 (57%) of households completed their repayment plans while remaining households owed on average 3.7 USD. There was weak evidence to suggest that intervention households collected more water per capita day than controls (adj coefficient: 3.45; 95CI: -2.51 to 9.41, p = 0.257). Intervention households had 11% higher absolute risk of owning a handwashing station compared against controls (95CI: 0.00 to 0.23; p = 0.06). There was no evidence of differences in ownership of soap or prevalence of childhood diarrhoea between study arms. Overall, operation and maintenance of the systems remained high, users demonstrated willingness to pay, and there was weak evidence that water provision at the household increased domestic consumption. However, the systems did not provide contaminant-free water. We conclude that HRWH using low-cost, locally available materials can increase household access to water in areas reliant on limited communal water sources.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"27 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134974069","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 : 2023-10-18DOI: 10.1371/journal.pwat.0000171
Savanna K. Smith, Benjamin B. Risk, Rochelle H. Holm, Elizabeth Tilley, Petros Chigwechokha, Drew Capone, Joe Brown, Francis L. de los Reyes
Despite the widespread global reliance on pit latrines as improved sanitation systems, the decomposition of waste within pit latrines is poorly understood. One area needing elucidation is the characterization and function of microbial communities within pit latrines. To address this gap, we characterized the microbial communities of 55 lined pit latrines at three sampling layers from two communities in peri-urban Malawi. The microbial communities of the fecal sludge samples were analyzed for beta diversity, pathogen presence, and functional profiling. Household surveys were conducted and used to compare microbial community patterns to household characteristics and pit latrine use patterns. Compared to activated sludge, anaerobic digestion in municipal wastewater systems, and human gut microbiomes, pit latrines were found to contain unique microbial communities. While the microbial community composition as a whole did not vary by sampling depth, pathogen composition varied by sampling depth, location, and household water source. The inferred microbial function also varied by depth ( e . g ., increase in methanogens and decrease in aerobes with depth). The richness of lined pit latrines determined from surface samples from eight latrines was found to be representative for a given area. Samples from middle and lower depths collected using a Gulper pump did not provide more information on richness, a result that informs future sampling designs. These findings are important for improving waste-based epidemiology (WBE) approaches to understand community health and waste degradation characterization of lined pit latrines.
{"title":"Microbial community function and bacterial pathogen composition in pit latrines in peri-urban Malawi","authors":"Savanna K. Smith, Benjamin B. Risk, Rochelle H. Holm, Elizabeth Tilley, Petros Chigwechokha, Drew Capone, Joe Brown, Francis L. de los Reyes","doi":"10.1371/journal.pwat.0000171","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000171","url":null,"abstract":"Despite the widespread global reliance on pit latrines as improved sanitation systems, the decomposition of waste within pit latrines is poorly understood. One area needing elucidation is the characterization and function of microbial communities within pit latrines. To address this gap, we characterized the microbial communities of 55 lined pit latrines at three sampling layers from two communities in peri-urban Malawi. The microbial communities of the fecal sludge samples were analyzed for beta diversity, pathogen presence, and functional profiling. Household surveys were conducted and used to compare microbial community patterns to household characteristics and pit latrine use patterns. Compared to activated sludge, anaerobic digestion in municipal wastewater systems, and human gut microbiomes, pit latrines were found to contain unique microbial communities. While the microbial community composition as a whole did not vary by sampling depth, pathogen composition varied by sampling depth, location, and household water source. The inferred microbial function also varied by depth ( e . g ., increase in methanogens and decrease in aerobes with depth). The richness of lined pit latrines determined from surface samples from eight latrines was found to be representative for a given area. Samples from middle and lower depths collected using a Gulper pump did not provide more information on richness, a result that informs future sampling designs. These findings are important for improving waste-based epidemiology (WBE) approaches to understand community health and waste degradation characterization of lined pit latrines.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"875 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135887997","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 : 2023-10-18DOI: 10.1371/journal.pwat.0000140
Kelly Hoffman, David Holcomb, Stacie Reckling, Thomas Clerkin, Denene Blackwood, Rachelle Beattie, Francis de los Reyes, Angela Harris, Helena Mitasova, Nadine Kotlarz, Jill Stewart, Jacob Kazenelson, Lawrence Cahoon, Arthur Frampton, Mariya Munir, Allison Lee, Steven Berkowitz, Rachel Noble, Virginia T. Guidry, Lawrence Engel, Marc Serre, Ariel Christensen
Wastewater surveillance emerged during the COVID-19 pandemic as a novel strategy for tracking the burden of illness in communities. Previous work has shown that trends in wastewater SARS-CoV-2 viral loads correlate well with reported COVID-19 case trends over longer time periods (i.e., months). We used detrending time series to reveal shorter sub-trend patterns (i.e., weeks) to identify leads or lags in the temporal alignment of the wastewater/case relationship. Daily incident COVID-19 cases and twice-weekly wastewater SARS-CoV-2 viral loads measured at 20 North Carolina sewersheds in 2021 were detrended using smoothing ranges of ∞, 16, 8, 4 and 2 weeks, to produce detrended cases and wastewater viral loads at progressively finer time scales. For each sewershed and smoothing range, we calculated the Spearman correlation between the cases and the wastewater viral loads with offsets of -7 to +7 days. We identified a conclusive lead/lag relationship at 15 of 20 sewersheds, with detrended wastewater loads temporally leading detrended COVID-19 cases at 11 of these sites. For the 11 leading sites, the correlation between wastewater loads and cases was greatest for wastewater loads sampled at a median lead time of 6 days before the cases were reported. Distinct lead/lag relationships were the most pronounced after detrending with smoothing ranges of 4–8 weeks, suggesting that SARS-CoV-2 wastewater viral loads can track fluctuations in COVID-19 case incidence rates at fine time scales and may serve as a leading indicator in many settings. These results could help public health officials identify, and deploy timely responses in, areas where cases are increasing faster than the overall pandemic trend.
{"title":"Using detrending to assess SARS-CoV-2 wastewater loads as a leading indicator of fluctuations in COVID-19 cases at fine temporal scales: Correlations across twenty sewersheds in North Carolina","authors":"Kelly Hoffman, David Holcomb, Stacie Reckling, Thomas Clerkin, Denene Blackwood, Rachelle Beattie, Francis de los Reyes, Angela Harris, Helena Mitasova, Nadine Kotlarz, Jill Stewart, Jacob Kazenelson, Lawrence Cahoon, Arthur Frampton, Mariya Munir, Allison Lee, Steven Berkowitz, Rachel Noble, Virginia T. Guidry, Lawrence Engel, Marc Serre, Ariel Christensen","doi":"10.1371/journal.pwat.0000140","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000140","url":null,"abstract":"Wastewater surveillance emerged during the COVID-19 pandemic as a novel strategy for tracking the burden of illness in communities. Previous work has shown that trends in wastewater SARS-CoV-2 viral loads correlate well with reported COVID-19 case trends over longer time periods (i.e., months). We used detrending time series to reveal shorter sub-trend patterns (i.e., weeks) to identify leads or lags in the temporal alignment of the wastewater/case relationship. Daily incident COVID-19 cases and twice-weekly wastewater SARS-CoV-2 viral loads measured at 20 North Carolina sewersheds in 2021 were detrended using smoothing ranges of ∞, 16, 8, 4 and 2 weeks, to produce detrended cases and wastewater viral loads at progressively finer time scales. For each sewershed and smoothing range, we calculated the Spearman correlation between the cases and the wastewater viral loads with offsets of -7 to +7 days. We identified a conclusive lead/lag relationship at 15 of 20 sewersheds, with detrended wastewater loads temporally leading detrended COVID-19 cases at 11 of these sites. For the 11 leading sites, the correlation between wastewater loads and cases was greatest for wastewater loads sampled at a median lead time of 6 days before the cases were reported. Distinct lead/lag relationships were the most pronounced after detrending with smoothing ranges of 4–8 weeks, suggesting that SARS-CoV-2 wastewater viral loads can track fluctuations in COVID-19 case incidence rates at fine time scales and may serve as a leading indicator in many settings. These results could help public health officials identify, and deploy timely responses in, areas where cases are increasing faster than the overall pandemic trend.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135887996","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}
The study aims to investigate the impact of anthropogenic influences within the catchment areas on the sediment physico-chemical quality of Owalla Reservoir in Osun State, Nigeria with the primary aim of creating baseline information on the aspect of limnology. Twenty sampling stations were established along the reservoir representing, its three different sections and two zones. The sampling was conducted for a period of two years to cover both seasons of the year in the area. The sediment samples were collected using a Van-Veen grab of 0.04 m 2 area (0.2m × 0.2m) from the waterbed at each sampling locations; labelled, kept in cooler at 4°C and transported to the laboratory for the analysis. The reservoir sediment was mainly clayey-sand in texture, while the particle size distribution was in this order: sand (73.1%) > clay (17.4%) > silt (9.4%). The exchangeable cations order of dominance was in this order: Mg 2+ > Ca 2+ > H + > Al 3+ > K + >Na + and anions in this order: PO 3 4 - > SO 4 2- > NO 3 - > Cl - . The highest mean values for water depth, transparency, air temperature, water temperature and sediment temperature (5.28 ± 0.40 m, 1.60 ± 0.05 m, 31.90 ± 0.29°C, 30.6 ± 0.18°C and 27.6 ± 0.23°C) were recorded during the dry season compared with the rainy season. The results obtained from this study, shows that Owalla Reservoir is fairly clean and not contaminated with toxic pollutants. The sediment pH is within acidic range, and enriched with nutrients due to the anthropogenic activities around this reservoir catchment areas. However, if the organic enrichments and siltation in this reservoir is not controlled, it could lead to the future eutrophication of this waterbody, which can cause water quality degradation, alter the aquatic biota and natural ageing process of this reservoir making it unsuitable for its purposes.
{"title":"Assessing the impact of anthropogenic influences on the sediment quality of Owalla Reservoir, Southwest, Nigeria","authors":"Adedeji Idowu Aduwo, Taiwo Adekanmi Adesakin, Abayomi Tolulope Oyewale, Israel Funso Adeniyi","doi":"10.1371/journal.pwat.0000135","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000135","url":null,"abstract":"The study aims to investigate the impact of anthropogenic influences within the catchment areas on the sediment physico-chemical quality of Owalla Reservoir in Osun State, Nigeria with the primary aim of creating baseline information on the aspect of limnology. Twenty sampling stations were established along the reservoir representing, its three different sections and two zones. The sampling was conducted for a period of two years to cover both seasons of the year in the area. The sediment samples were collected using a Van-Veen grab of 0.04 m 2 area (0.2m × 0.2m) from the waterbed at each sampling locations; labelled, kept in cooler at 4°C and transported to the laboratory for the analysis. The reservoir sediment was mainly clayey-sand in texture, while the particle size distribution was in this order: sand (73.1%) > clay (17.4%) > silt (9.4%). The exchangeable cations order of dominance was in this order: Mg 2+ > Ca 2+ > H + > Al 3+ > K + >Na + and anions in this order: PO 3 4 - > SO 4 2- > NO 3 - > Cl - . The highest mean values for water depth, transparency, air temperature, water temperature and sediment temperature (5.28 ± 0.40 m, 1.60 ± 0.05 m, 31.90 ± 0.29°C, 30.6 ± 0.18°C and 27.6 ± 0.23°C) were recorded during the dry season compared with the rainy season. The results obtained from this study, shows that Owalla Reservoir is fairly clean and not contaminated with toxic pollutants. The sediment pH is within acidic range, and enriched with nutrients due to the anthropogenic activities around this reservoir catchment areas. However, if the organic enrichments and siltation in this reservoir is not controlled, it could lead to the future eutrophication of this waterbody, which can cause water quality degradation, alter the aquatic biota and natural ageing process of this reservoir making it unsuitable for its purposes.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"249 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098107","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 : 2023-10-11DOI: 10.1371/journal.pwat.0000136
Ricardo Sánchez-Murillo, Luis González-Hita, Miguel A. Mejía-González, Blanca Carteño-Martinez, Juan C. Aparicio-González, Dustin Mañón-Flores, Lucía Ortega, Milica Stojanovic, Raquel Nieto, Luis Gimeno
Mexico encompasses a large spectrum of landscapes with topographic, geographic, and climatic factors interacting in a complex ecohydrological setting. For decades, isotope hydrogeological tools have been applied in Mexico using short-term or seasonal local meteoric water lines as valid input functions. Yet, a systematic evaluation of meteoric isotope characteristics is still lacking. Here we report on the spatial and temporal isotope variations of 21 precipitation monitoring stations across Mexico. Our database includes 608 monthly samples collected from 2018 to 2021 over four regions (between 5 and 2,365 m asl): the Pacific coast, the Gulf of Mexico/Caribbean Sea region, and the Central and Northern plateaus. Precipitation δ 18 O seasonality from the dry (winter) to the wet season (summer) was characterized by a notable W-shaped variability. Monthly precipitation amounts and δ 18 O compositions exhibited poor to strong linear regressions ( Adj . r 2 <0.01 to 0.75), with inverse (positive) relationships over the northern monsoon-affected region. Low d -excess (5.1 to 9.7‰) corresponded with greater terrestrial moisture contributions (20.5%) over the arid northern regions. Moisture inputs from the Gulf of Mexico/Caribbean Sea and the Pacific Ocean were associated with near-equilibrium or greater d -excess values (8.8 to 14.3‰), respectively. The best-fit linear models for δ 18 O ( Adj . r 2 = 0.85) and δ 2 H ( Adj . r 2 = 0.88) were determined for topographic and geographical predictors, resulting in an updated high-resolution precipitation isoscape (100 m 2 grid) for Mexico. Orographic barriers (-2.10‰ in δ 18 O/km) coupled with the interaction of tropical cyclones and cold fronts, the evolution of the North American Monsoon system, and the passage of easterly trade winds play a remarkable role in controlling the spatial isotope rainfall variability. Our findings provide a robust baseline for ecohydrological, climatic, forensic, archeological, and paleoclimate studies in North America.
{"title":"Tracing isotope precipitation patterns across Mexico","authors":"Ricardo Sánchez-Murillo, Luis González-Hita, Miguel A. Mejía-González, Blanca Carteño-Martinez, Juan C. Aparicio-González, Dustin Mañón-Flores, Lucía Ortega, Milica Stojanovic, Raquel Nieto, Luis Gimeno","doi":"10.1371/journal.pwat.0000136","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000136","url":null,"abstract":"Mexico encompasses a large spectrum of landscapes with topographic, geographic, and climatic factors interacting in a complex ecohydrological setting. For decades, isotope hydrogeological tools have been applied in Mexico using short-term or seasonal local meteoric water lines as valid input functions. Yet, a systematic evaluation of meteoric isotope characteristics is still lacking. Here we report on the spatial and temporal isotope variations of 21 precipitation monitoring stations across Mexico. Our database includes 608 monthly samples collected from 2018 to 2021 over four regions (between 5 and 2,365 m asl): the Pacific coast, the Gulf of Mexico/Caribbean Sea region, and the Central and Northern plateaus. Precipitation δ 18 O seasonality from the dry (winter) to the wet season (summer) was characterized by a notable W-shaped variability. Monthly precipitation amounts and δ 18 O compositions exhibited poor to strong linear regressions ( Adj . r 2 <0.01 to 0.75), with inverse (positive) relationships over the northern monsoon-affected region. Low d -excess (5.1 to 9.7‰) corresponded with greater terrestrial moisture contributions (20.5%) over the arid northern regions. Moisture inputs from the Gulf of Mexico/Caribbean Sea and the Pacific Ocean were associated with near-equilibrium or greater d -excess values (8.8 to 14.3‰), respectively. The best-fit linear models for δ 18 O ( Adj . r 2 = 0.85) and δ 2 H ( Adj . r 2 = 0.88) were determined for topographic and geographical predictors, resulting in an updated high-resolution precipitation isoscape (100 m 2 grid) for Mexico. Orographic barriers (-2.10‰ in δ 18 O/km) coupled with the interaction of tropical cyclones and cold fronts, the evolution of the North American Monsoon system, and the passage of easterly trade winds play a remarkable role in controlling the spatial isotope rainfall variability. Our findings provide a robust baseline for ecohydrological, climatic, forensic, archeological, and paleoclimate studies in North America.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136097978","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 : 2023-09-27DOI: 10.1371/journal.pwat.0000052
Julio A. Polanco, Jana Safarik, Jason S. Dadakis, Claire Johnson, Megan H. Plumlee
Primary and secondary treatment of municipal wastewater contributes to virus removal upstream of advanced purification to produce water for potable reuse. In this study, virus occurrence by cultivable and molecular methods was measured over a 24-month period in raw wastewater influents and secondary effluents from two municipal wastewater treatment plants that together provide the recycled water source for an advanced water purification facility. Using a rank-paired, covariance-based statistical approach, virus log removal values were determined for four wastewater treatment processes that operate in parallel at the two facilities (two activated sludge processes, trickling filter process, and trickling filter/solids contactor process). The trickling filter process exhibited the lowest observed removal of cultivable enteric virus with a median removal of 1.0 log 10 (or 90% removal) and a 5 th percentile log removal of 0.73 (or 82%), compared to the greatest removal observed for one of the activated sludge processes (median log removal of 2.4 or 99.6% and 5 th percentile of 2.1 or 99.2%). Median log removal observed for male-specific (MS) and somatic (SOM) coliphage was 1.8 (98.6% removal) and 0.5 (70%), respectively, for trickling filter and 2.9 (99.9%) and 2.0 (99%) for activated sludge. Thus, coliphage removal was fairly similar to removal observed for cultivable enteric virus. The cultivable enteric virus 5 th percentile removal (0.7) from the trickling filter treatment process was proposed to the state regulator for credit towards state requirements for virus removal related to groundwater augmentation with purified recycled water. Receiving pathogen removal credits for secondary wastewater treatment would allow for an improved margin (safety factor) of credits beyond the minimum required; and in this case may also increase the number of viable future groundwater recharge sites closer to drinking water production wells by reducing the underground travel time otherwise required to obtain sufficient credits.
{"title":"Enteric virus removal by municipal wastewater treatment to achieve requirements for potable reuse","authors":"Julio A. Polanco, Jana Safarik, Jason S. Dadakis, Claire Johnson, Megan H. Plumlee","doi":"10.1371/journal.pwat.0000052","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000052","url":null,"abstract":"Primary and secondary treatment of municipal wastewater contributes to virus removal upstream of advanced purification to produce water for potable reuse. In this study, virus occurrence by cultivable and molecular methods was measured over a 24-month period in raw wastewater influents and secondary effluents from two municipal wastewater treatment plants that together provide the recycled water source for an advanced water purification facility. Using a rank-paired, covariance-based statistical approach, virus log removal values were determined for four wastewater treatment processes that operate in parallel at the two facilities (two activated sludge processes, trickling filter process, and trickling filter/solids contactor process). The trickling filter process exhibited the lowest observed removal of cultivable enteric virus with a median removal of 1.0 log 10 (or 90% removal) and a 5 th percentile log removal of 0.73 (or 82%), compared to the greatest removal observed for one of the activated sludge processes (median log removal of 2.4 or 99.6% and 5 th percentile of 2.1 or 99.2%). Median log removal observed for male-specific (MS) and somatic (SOM) coliphage was 1.8 (98.6% removal) and 0.5 (70%), respectively, for trickling filter and 2.9 (99.9%) and 2.0 (99%) for activated sludge. Thus, coliphage removal was fairly similar to removal observed for cultivable enteric virus. The cultivable enteric virus 5 th percentile removal (0.7) from the trickling filter treatment process was proposed to the state regulator for credit towards state requirements for virus removal related to groundwater augmentation with purified recycled water. Receiving pathogen removal credits for secondary wastewater treatment would allow for an improved margin (safety factor) of credits beyond the minimum required; and in this case may also increase the number of viable future groundwater recharge sites closer to drinking water production wells by reducing the underground travel time otherwise required to obtain sufficient credits.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135535650","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 : 2023-09-20DOI: 10.1371/journal.pwat.0000180
Abishek Sankara Narayan, Marisa Boller
The provision of basic water and waste services, i.e., water supply, sanitation, solid waste and stormwater management, is essential for ensuring public and environmental health. These services are closely interconnected in their physical chains, creating both opportunities and challenges for service delivery [1]. Negative interlinkages can occur when solid waste enters pit latrines or faecal matter contaminates drinking water. On the other hand, there are opportunities for synergies, such as the reuse of treated wastewater or the co-digestion of faecal and organic waste. Despite these known synergies, institutional arrangements remain fragmented, and sectors continue to operate in isolated siloes. This raises the question: Should planning, implementation and management of these basic services be integrated? At the All Systems Connect Symposium 2023 in The Hague [2], six eminent speakers from academia, government, non-governmental organizations (NGOs) and the private sector debated this issue. This article presents the four key issues that were raised when considering integration of water and waste services in low-resource settings.
{"title":"To integrate or not to integrate? Water and waste as unified basic services","authors":"Abishek Sankara Narayan, Marisa Boller","doi":"10.1371/journal.pwat.0000180","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000180","url":null,"abstract":"The provision of basic water and waste services, i.e., water supply, sanitation, solid waste and stormwater management, is essential for ensuring public and environmental health. These services are closely interconnected in their physical chains, creating both opportunities and challenges for service delivery [1]. Negative interlinkages can occur when solid waste enters pit latrines or faecal matter contaminates drinking water. On the other hand, there are opportunities for synergies, such as the reuse of treated wastewater or the co-digestion of faecal and organic waste. Despite these known synergies, institutional arrangements remain fragmented, and sectors continue to operate in isolated siloes. This raises the question: Should planning, implementation and management of these basic services be integrated? At the All Systems Connect Symposium 2023 in The Hague [2], six eminent speakers from academia, government, non-governmental organizations (NGOs) and the private sector debated this issue. This article presents the four key issues that were raised when considering integration of water and waste services in low-resource settings.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"352 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136306520","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 : 2023-09-20DOI: 10.1371/journal.pwat.0000178
Abigail K. Kargol, Samantha R. Burrell, Indrajit Chakraborty, Heidi L. Gough
The wastewater used for experimental research is typically collected from a wastewater treatment plant or prepared as a synthetic solution in the lab. These options represent transportation and cost challenges, respectively, particularly for experiments requiring large volumes of wastewater. Here, we describe a method for creating inexpensive synthetic wastewater from readily available household products. The base solution, synthesized by soaking dog food pellets for 24 hours and straining the solution, had average nutrient values of 9.7 mg/L ammonia as N, 12.2 mg/L nitrate as N, 227 mg/L total nitrogen, and 4870 mg/L chemical oxygen demand (COD). Degradation tests demonstrated that soluble COD was biodegradable. The base solution was then used to prepare synthetic wastewater that met the requirements for two experimental applications; (1) anaerobic treatment of primary effluent and (2) land-application treatment of secondary effluent. Cost analysis indicated that the single-ingredient synthetic wastewater cost 92% less to produce than synthetic wastewater recipes that used laboratory chemicals, and reduced preparation time. These results demonstrated that use of commercial products can simplify the wastewater synthesis process and reduce experimental costs for large-volume research applications while still maintaining consistent wastewater characterization.
{"title":"Synthetic wastewater prepared from readily available materials: Characteristics and economics","authors":"Abigail K. Kargol, Samantha R. Burrell, Indrajit Chakraborty, Heidi L. Gough","doi":"10.1371/journal.pwat.0000178","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000178","url":null,"abstract":"The wastewater used for experimental research is typically collected from a wastewater treatment plant or prepared as a synthetic solution in the lab. These options represent transportation and cost challenges, respectively, particularly for experiments requiring large volumes of wastewater. Here, we describe a method for creating inexpensive synthetic wastewater from readily available household products. The base solution, synthesized by soaking dog food pellets for 24 hours and straining the solution, had average nutrient values of 9.7 mg/L ammonia as N, 12.2 mg/L nitrate as N, 227 mg/L total nitrogen, and 4870 mg/L chemical oxygen demand (COD). Degradation tests demonstrated that soluble COD was biodegradable. The base solution was then used to prepare synthetic wastewater that met the requirements for two experimental applications; (1) anaerobic treatment of primary effluent and (2) land-application treatment of secondary effluent. Cost analysis indicated that the single-ingredient synthetic wastewater cost 92% less to produce than synthetic wastewater recipes that used laboratory chemicals, and reduced preparation time. These results demonstrated that use of commercial products can simplify the wastewater synthesis process and reduce experimental costs for large-volume research applications while still maintaining consistent wastewater characterization.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136306523","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 : 2023-09-19DOI: 10.1371/journal.pwat.0000117
K. Clark Appling, Mark D. Sobsey, Lisa M. Durso, Michael B. Fisher
Antimicrobial resistance (AMR) threatens human and animal health; effective response requires monitoring AMR presence in humans, animals, and the environment. The World Health Organization Tricycle Protocol (WHO TP) standardizes and streamlines global AMR monitoring around a single indicator organism, extended-spectrum-β-lactamase-producing Escherichia coli (ESBL-Ec). The WHO TP culture-based method detects and quantifies ESBL-Ec by spread-plating or membrane filtration on either MacConkey or TBX agar (supplemented with cefotaxime). These methods require laboratories and trained personnel, limiting feasibility in low-resource and field settings. We adapted the WHO TP using a simplified method, the compartment bag test (CBT), to quantify most probable numbers (MPN) of ESBL-Ec in samples. CBT methods can be used correctly in the field by typical adults after a few hours’ training. We collected and analyzed municipal wastewater, surface water, and chicken waste samples from sites in Raleigh and Chapel Hill, NC over an 8-month period. Presumptive ESBL-Ec were quantified using MF on TBX agar supplemented with cefotaxime (MF+TBX), as well as using the CBT with chromogenic E . coli medium containing cefotaxime. Presumptive ESBL-Ec bacteria were isolated from completed tests for confirmation and characterization by Kirby Bauer disk diffusion tests (antibiotic sensitivity) and EnteroPluri biochemical tests (speciation). Both methods were easy to use, but MF+TBX required additional time and effort. The proportion of E . coli that were presumptively ESBL in surface water samples was significantly greater downstream vs upstream of wastewater treatment plant (WWTP) outfalls, suggesting that treated wastewater is a source of ESBL-Ec in some surface waters. The CBT and MF+TBX tests provided similar (but not identical) quantitative results, making the former method suitable as an alternative to the more complex MF+TBX procedure in some applications. Further AMR surveillance using MF+TBX and/or CBT methods may be useful to characterize and refine their performance for AMR monitoring in NC and elsewhere.
{"title":"Environmental monitoring of antimicrobial resistant bacteria in North Carolina water and wastewater using the WHO Tricycle protocol in combination with membrane filtration and compartment bag test methods for detecting and quantifying ESBL E. coli","authors":"K. Clark Appling, Mark D. Sobsey, Lisa M. Durso, Michael B. Fisher","doi":"10.1371/journal.pwat.0000117","DOIUrl":"https://doi.org/10.1371/journal.pwat.0000117","url":null,"abstract":"Antimicrobial resistance (AMR) threatens human and animal health; effective response requires monitoring AMR presence in humans, animals, and the environment. The World Health Organization Tricycle Protocol (WHO TP) standardizes and streamlines global AMR monitoring around a single indicator organism, extended-spectrum-β-lactamase-producing Escherichia coli (ESBL-Ec). The WHO TP culture-based method detects and quantifies ESBL-Ec by spread-plating or membrane filtration on either MacConkey or TBX agar (supplemented with cefotaxime). These methods require laboratories and trained personnel, limiting feasibility in low-resource and field settings. We adapted the WHO TP using a simplified method, the compartment bag test (CBT), to quantify most probable numbers (MPN) of ESBL-Ec in samples. CBT methods can be used correctly in the field by typical adults after a few hours’ training. We collected and analyzed municipal wastewater, surface water, and chicken waste samples from sites in Raleigh and Chapel Hill, NC over an 8-month period. Presumptive ESBL-Ec were quantified using MF on TBX agar supplemented with cefotaxime (MF+TBX), as well as using the CBT with chromogenic E . coli medium containing cefotaxime. Presumptive ESBL-Ec bacteria were isolated from completed tests for confirmation and characterization by Kirby Bauer disk diffusion tests (antibiotic sensitivity) and EnteroPluri biochemical tests (speciation). Both methods were easy to use, but MF+TBX required additional time and effort. The proportion of E . coli that were presumptively ESBL in surface water samples was significantly greater downstream vs upstream of wastewater treatment plant (WWTP) outfalls, suggesting that treated wastewater is a source of ESBL-Ec in some surface waters. The CBT and MF+TBX tests provided similar (but not identical) quantitative results, making the former method suitable as an alternative to the more complex MF+TBX procedure in some applications. Further AMR surveillance using MF+TBX and/or CBT methods may be useful to characterize and refine their performance for AMR monitoring in NC and elsewhere.","PeriodicalId":93672,"journal":{"name":"PLOS water","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135059356","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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