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Cassivi A, Tilley E, Waygood EOD, Dorea C. Household practices in accessing drinking water and post collection contamination: A seasonal cohort study in Malawi. WATER RESEARCH 2021; 189:116607. [PMID: 33197683 DOI: 10.1016/j.watres.2020.116607] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 06/11/2023]
Abstract
Lack of access to safe drinking water on premises remains widespread in low- and middle-income countries. Interventions to improve access to safe water at the point of collection are essential, but water safety at the point of consumption is also an important consideration. This research aimed to 1) improve understanding of household practices in collecting water with respect to seasonality, and 2) to further assess risk associated with post-collection contamination from the point of collection to the point of consumption. A seasonal cohort study, including 115 households, was conducted in Malawi. Along with household surveys and observations, samples of water were tested for microbial water quality at four different stages of water collection: water source, collection container, storage container, cup of drinking water. Using E. coli as an indicator of contamination (cfu/100 ml), the risk of post-collection contamination was assessed. The results indicate that most water sources were free from contamination; contamination was proportionally lower in the dry season when more sources were found to be classified as having a very low risk of contamination. However, the level of risk of contamination was more likely to increase following collection in water sources that were initially free from contamination. Results show that the degradation in water quality from the point of collection to the point of consumption was more important in the rainy season, which is likely to be driven by the effect of seasonality on the household environment. Filling the collection container at the point of collection and storage at the point of consumption were found to be critical stages for an increased risk of E. coli contamination. Understanding household practices in accessing and handling water during both rainy and dry season is necessary to target appropriate interventions to reduce post-collection contamination.
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Affiliation(s)
- Alexandra Cassivi
- University of Victoria, Department of Civil Engineering, Engineering and Computer Science (ECS) 304, PO Box 1700 STN CSC, Victoria BC V8W 2Y2, Canada.
| | - Elizabeth Tilley
- University of Malawi, The Polytechnic, Private Bag 303, Blantyre 3, Malawi; Eawag: Swiss Federal Institute Of Aquatic Science And Technology, Überlandstr. 133, 8600 Dübendorf, Switzerland
| | - E Owen D Waygood
- Polytechnique Montreal, Department of Civil, Geological and Mining Engineering, PO Box 6079, Montréal QC H3C 3A7, Canada
| | - Caetano Dorea
- University of Victoria, Department of Civil Engineering, Engineering and Computer Science (ECS) 304, PO Box 1700 STN CSC, Victoria BC V8W 2Y2, Canada
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Traoré AN, Mulaudzi K, Chari GJE, Foord SH, Mudau LS, Barnard TG, Potgieter N. The Impact of Human Activities on Microbial Quality of Rivers in the Vhembe District, South Africa. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:ijerph13080817. [PMID: 27529265 PMCID: PMC4997503 DOI: 10.3390/ijerph13080817] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 07/26/2016] [Accepted: 07/28/2016] [Indexed: 11/16/2022]
Abstract
Background: Water quality testing is dictated by microbial agents found at the time of sampling in reference to their acceptable risk levels. Human activities might contaminate valuable water resources and add to the microbial load present in water bodies. Therefore, the effects of human activities on the microbial quality of rivers collected from twelve catchments in the Vhembe District in South Africa were investigated, with samples analyzed for total coliform (TC) and Eschericha coli (E. coli) contents. Methods: Physical parameters and various human activities were recorded for each sampling site. The Quanti-Tray® method was adopted for the assessment of TC and E. coli contents in the rivers over a two-year period. A multiplex polymerase chain (PCR) method was used to characterize the strains of E. coli found. Results: The microbial quality of the rivers was poor with both TC and E. coli contents found to be over acceptable limits set by the South African Department of Water and Sanitation (DWS). No significant difference (p > 0.05) was detected between TC and E. coli risks in dry and wet seasons. All six pathogenic E. coli strains were identified and Enteroaggregative E. coli (EAEC), atypical Enteropathogenic E. coli (a-EPEC) and Enterotoxigenic E. coli (ETEC) were the most prevalent E. coli strains detected (respectively, 87%, 86% and 83%). Conclusions: The study indicated that contamination in the majority of sampling sites, due to human activities such as car wash, animal grazing and farming, poses health risks to communities using the rivers for various domestic chores. It is therefore recommended that more education by the respective departments is done to avert pollution of rivers and prevent health risks to the communities in the Vhembe District.
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Affiliation(s)
- Afsatou N Traoré
- Microbiology Department, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.
| | - Khodani Mulaudzi
- Microbiology Department, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.
| | - Gamuchirai J E Chari
- Microbiology Department, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.
| | - Stefan H Foord
- Zoology Department, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.
| | - Lutendo S Mudau
- Department of Environmental Health, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa.
| | - Tobias G Barnard
- Water & Health Research Unit, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg 2006, South Africa.
| | - Natasha Potgieter
- Microbiology Department, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.
- Dean, School of Mathematical and Natural Sciences, University of Venda, Private Bag X5050, Thohoyandou 0950, South Africa.
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Lui GY, Roser D, Corkish R, Ashbolt NJ, Stuetz R. Point-of-use water disinfection using ultraviolet and visible light-emitting diodes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 553:626-635. [PMID: 26967007 DOI: 10.1016/j.scitotenv.2016.02.039] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270-740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6h. Five log10 and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log10s E. coli and E. faecalis over the 6h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for >3-log10 reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5-2.5 fold at 365-455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work.
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Affiliation(s)
- Gough Yumu Lui
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia; School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | - David Roser
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Richard Corkish
- School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Nicholas J Ashbolt
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia; School of Public Health, South Academic Building, University of Alberta, Edmonton, Alberta T6G 2G7, Canada.
| | - Richard Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
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Shields KF, Bain RES, Cronk R, Wright JA, Bartram J. Association of Supply Type with Fecal Contamination of Source Water and Household Stored Drinking Water in Developing Countries: A Bivariate Meta-analysis. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:1222-31. [PMID: 25956006 PMCID: PMC4671240 DOI: 10.1289/ehp.1409002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 05/06/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND Access to safe drinking water is essential for health. Monitoring access to drinking water focuses on water supply type at the source, but there is limited evidence on whether quality differences at the source persist in water stored in the household. OBJECTIVES We assessed the extent of fecal contamination at the source and in household stored water (HSW) and explored the relationship between contamination at each sampling point and water supply type. METHODS We performed a bivariate random-effects meta-analysis of 45 studies, identified through a systematic review, that reported either the proportion of samples free of fecal indicator bacteria and/or individual sample bacteria counts for source and HSW, disaggregated by supply type. RESULTS Water quality deteriorated substantially between source and stored water. The mean percentage of contaminated samples (noncompliance) at the source was 46% (95% CI: 33, 60%), whereas mean noncompliance in HSW was 75% (95% CI: 64, 84%). Water supply type was significantly associated with noncompliance at the source (p < 0.001) and in HSW (p = 0.03). Source water (OR = 0.2; 95% CI: 0.1, 0.5) and HSW (OR = 0.3; 95% CI: 0.2, 0.8) from piped supplies had significantly lower odds of contamination compared with non-piped water, potentially due to residual chlorine. CONCLUSIONS Piped water is less likely to be contaminated compared with other water supply types at both the source and in HSW. A focus on upgrading water services to piped supplies may help improve safety, including for those drinking stored water.
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Affiliation(s)
- Katherine F Shields
- The Water Institute, University of North Carolina at Chapel Hill, Chapel Hill North Carolina, USA
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Mattioli MCM, Davis J, Boehm AB. Hand-to-mouth contacts result in greater ingestion of feces than dietary water consumption in Tanzania: a quantitative fecal exposure assessment model. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:1912-20. [PMID: 25559008 DOI: 10.1021/es505555f] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Diarrheal diseases kill 1800 children under the age of five die each day, and nearly half of these deaths occur in sub-Saharan Africa. Contaminated drinking water and hands are two important environmental transmission routes of diarrhea-causing pathogens to young children in low-income countries. The objective of this research is to evaluate the relative contribution of these two major exposure pathways in a low-income country setting. A Monte Carlo simulation was used to model the amount of human feces ingested by children under five years old from exposure via hand-to-mouth contacts and stored drinking water ingestion in Bagamoyo, Tanzania. Child specific exposure data were obtained from the USEPA 2011 Exposure Factors Handbook, and fecal contamination was estimated using hand rinse and stored water fecal indicator bacteria concentrations from over 1200 Tanzanian households. The model outcome is a distribution of a child's daily dose of feces via each exposure route. The model results show that Tanzanian children ingest a significantly greater amount of feces each day from hand-to-mouth contacts than from drinking water, which may help elucidate why interventions focused on water without also addressing hygiene often see little to no effect on reported incidence of diarrhea.
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Affiliation(s)
- Mia Catharine M Mattioli
- Environmental and Water Studies, Department of Civil and Environmental Engineering, Stanford University , Stanford, California 94305, United States
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Lui GY, Roser D, Corkish R, Ashbolt N, Jagals P, Stuetz R. Photovoltaic powered ultraviolet and visible light-emitting diodes for sustainable point-of-use disinfection of drinking waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 493:185-196. [PMID: 24946032 DOI: 10.1016/j.scitotenv.2014.05.104] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/23/2014] [Accepted: 05/23/2014] [Indexed: 06/03/2023]
Abstract
For many decades, populations in rural and remote developing regions will be unable to access centralised piped potable water supplies, and indeed, decentralised options may be more sustainable. Accordingly, improved household point-of-use (POU) disinfection technologies are urgently needed. Compared to alternatives, ultraviolet (UV) light disinfection is very attractive because of its efficacy against all pathogen groups and minimal operational consumables. Though mercury arc lamp technology is very efficient, it requires frequent lamp replacement, involves a toxic heavy metal, and their quartz envelopes and sleeves are expensive, fragile and require regular cleaning. An emerging alternative is semiconductor-based units where UV light emitting diodes (UV-LEDs) are powered by photovoltaics (PV). Our review charts the development of these two technologies, their current status, and challenges to their integration and POU application. It explores the themes of UV-C-LEDs, non-UV-C LED technology (e.g. UV-A, visible light, Advanced Oxidation), PV power supplies, PV/LED integration and POU suitability. While UV-C LED technology should mature in the next 10 years, research is also needed to address other unresolved barriers to in situ application as well as emerging research opportunities especially UV-A, photocatalyst/photosensitiser use and pulsed emission options.
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Affiliation(s)
- Gough Yumu Lui
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - David Roser
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Richard Corkish
- School of Photovoltaics and Renewable Energy Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Nicholas Ashbolt
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; School of Public Health , Room 3-57D, South Academic Building, University of Alberta, Edmonton, Alberta, T6G 2G7, Canada.
| | - Paul Jagals
- School of Population Health, University of Queensland, Brisbane, 4006, Australia.
| | - Richard Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
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Bain R, Cronk R, Wright J, Yang H, Slaymaker T, Bartram J. Fecal contamination of drinking-water in low- and middle-income countries: a systematic review and meta-analysis. PLoS Med 2014; 11:e1001644. [PMID: 24800926 PMCID: PMC4011876 DOI: 10.1371/journal.pmed.1001644] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 04/03/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Access to safe drinking-water is a fundamental requirement for good health and is also a human right. Global access to safe drinking-water is monitored by WHO and UNICEF using as an indicator "use of an improved source," which does not account for water quality measurements. Our objectives were to determine whether water from "improved" sources is less likely to contain fecal contamination than "unimproved" sources and to assess the extent to which contamination varies by source type and setting. METHODS AND FINDINGS Studies in Chinese, English, French, Portuguese, and Spanish were identified from online databases, including PubMed and Web of Science, and grey literature. Studies in low- and middle-income countries published between 1990 and August 2013 that assessed drinking-water for the presence of Escherichia coli or thermotolerant coliforms (TTC) were included provided they associated results with a particular source type. In total 319 studies were included, reporting on 96,737 water samples. The odds of contamination within a given study were considerably lower for "improved" sources than "unimproved" sources (odds ratio [OR] = 0.15 [0.10-0.21], I2 = 80.3% [72.9-85.6]). However over a quarter of samples from improved sources contained fecal contamination in 38% of 191 studies. Water sources in low-income countries (OR = 2.37 [1.52-3.71]; p<0.001) and rural areas (OR = 2.37 [1.47-3.81] p<0.001) were more likely to be contaminated. Studies rarely reported stored water quality or sanitary risks and few achieved robust random selection. Safety may be overestimated due to infrequent water sampling and deterioration in quality prior to consumption. CONCLUSION Access to an "improved source" provides a measure of sanitary protection but does not ensure water is free of fecal contamination nor is it consistent between source types or settings. International estimates therefore greatly overstate use of safe drinking-water and do not fully reflect disparities in access. An enhanced monitoring strategy would combine indicators of sanitary protection with measures of water quality.
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Affiliation(s)
- Robert Bain
- The Water Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Ryan Cronk
- The Water Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jim Wright
- University of Southampton, Southampton, United Kingdom
| | - Hong Yang
- University of Southampton, Southampton, United Kingdom
| | | | - Jamie Bartram
- The Water Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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