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Yu W, Wanza P, Kwoba E, Mwangi T, Okotto-Okotto J, Trajano Gomes da Silva D, Wright JA. Modelling seasonal household variation in harvested rainwater availability: a case study in Siaya County, Kenya. NPJ Clean Water 2023; 6:32. [PMID: 37073161 PMCID: PMC10099009 DOI: 10.1038/s41545-023-00247-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/23/2023] [Indexed: 05/03/2023]
Abstract
Rainwater harvesting reliability, the proportion of days annually when rainwater demand is fully met, is challenging to estimate from cross-sectional household surveys that underpin international monitoring. This study investigated the use of a modelling approach that integrates household surveys with gridded precipitation data to evaluate rainwater harvesting reliability, using two local-scale household surveys in rural Siaya County, Kenya as an illustrative case study. We interviewed 234 households, administering a standard questionnaire that also identified the source of household stored drinking water. Logistic mixed effects models estimated stored rainwater availability from household and climatological variables, with random effects accounting for unobserved heterogeneity. Household rainwater availability was significantly associated with seasonality, storage capacity, and access to alternative improved water sources. Most households (95.1%) that consumed rainwater faced insufficient supply of rainwater available for potable needs throughout the year, with intermittencies during the short rains for most households with alternative improved sources. Although not significant, stored rainwater lasts longer for households whose only improved water source was rainwater (301.8 ± 40.2 days) compared to those having multiple improved sources (144.4 ± 63.7 days). Such modelling analysis could enable rainwater harvesting reliability estimation, and thereby national/international monitoring and targeted follow-up fieldwork to support rainwater harvesting.
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Affiliation(s)
- Weiyu Yu
- School of Ecological Technology and Engineering, Shanghai Institute of Technology, Fengxian campus, Shanghai, 201418 China
- School of Geography and Environmental Science, University of Southampton, Building 44, Highfield campus, Southampton, SO17 1BJ UK
| | - Peggy Wanza
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. BOX 1578-1400, Kisian campus, Kisumu-Busia Highway, Kisumu, Kenya
| | - Emmah Kwoba
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. BOX 1578-1400, Kisian campus, Kisumu-Busia Highway, Kisumu, Kenya
| | - Thumbi Mwangi
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. BOX 1578-1400, Kisian campus, Kisumu-Busia Highway, Kisumu, Kenya
- Paul G Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090 USA
| | - Joseph Okotto-Okotto
- Victoria Institute for Research on Environment and Development (VIRED) International, P.O. BOX 6423-40103, off Nairobi Road, Rabuor, Kenya
| | - Diogo Trajano Gomes da Silva
- Environmental and Public Health Research and Enterprise Group, School of Applied Sciences, University of Brighton, Cockcroft Building, Lewes Road, Brighton, BN2 4GJ UK
| | - Jim A. Wright
- School of Geography and Environmental Science, University of Southampton, Building 44, Highfield campus, Southampton, SO17 1BJ UK
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Okotto-Okotto J, Yu W, Kwoba E, Thumbi SM, Okotto LG, Wanza P, Trajano Gomes da Silva D, Wright J. A mixed methods study to evaluate participatory mapping for rural water safety planning in western Kenya. PLoS One 2021; 16:e0255286. [PMID: 34320036 PMCID: PMC8318241 DOI: 10.1371/journal.pone.0255286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 07/13/2021] [Indexed: 11/21/2022] Open
Abstract
Water safety planning is an approach to ensure safe drinking-water access through comprehensive risk assessment and water supply management from catchment to consumer. However, its uptake remains low in rural areas. Participatory mapping, the process of map creation for resource management by local communities, has yet to be used for rural water safety planning. In this mixed methods study, to evaluate the validity of participatory mapping outputs for rural water safety planning and assess community understanding of water safety, 140 community members in Siaya County, Kenya, attended ten village-level participatory mapping sessions. They mapped drinking-water sources, ranked their safety and mapped potential contamination hazards. Findings were triangulated against a questionnaire survey of 234 households, conducted in parallel. In contrast to source type ranking for international monitoring, workshop participants ranked rainwater's safety above piped water and identified source types such as broken pipes not explicitly recorded in water source typologies often used for formal monitoring. Participatory mapping also highlighted the overlap between livestock grazing areas and household water sources. These findings were corroborated by the household survey and subsequent participatory meetings. However, comparison with household survey data suggested participatory mapping outputs omitted some water sources and landscape-scale contamination hazards, such as open defecation areas or flood-prone areas. In follow-up visits, participant groups ranked remediation of rainwater harvesting systems as the most acceptable intervention to address hazards. We conclude that participatory mapping can complement other established approaches to rural water safety planning by capturing informally managed source use and facilitating community engagement.
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Affiliation(s)
- Joseph Okotto-Okotto
- Victoria Institute for Research on Environment and Development (VIRED) International, Rabuor, Kisumu, Kenya
| | - Weiyu Yu
- School of Geography and Environmental Science, University of Southampton, Highfield, Southampton, United Kingdom
| | - Emmah Kwoba
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Samuel M. Thumbi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Paul G Allen School for Global Animal Health, Washington State University, Pullman, WA, United States of America
- Institute of Tropical and Infectious Diseases, University of Nairobi, Nairobi, Kenya
| | - Lorna Grace Okotto
- School of Spatial Planning and Natural Resource Management, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Peggy Wanza
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Jim Wright
- School of Geography and Environmental Science, University of Southampton, Highfield, Southampton, United Kingdom
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Trajano Gomes da Silva D, Ebdon J, Okotto-Okotto J, Ade F, Mito O, Wanza P, Kwoba E, Mwangi T, Yu W, Wright JA. A longitudinal study of the association between domestic contact with livestock and contamination of household point-of-use stored drinking water in rural Siaya County (Kenya). Int J Hyg Environ Health 2020; 230:113602. [PMID: 32911124 PMCID: PMC7607227 DOI: 10.1016/j.ijheh.2020.113602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/20/2020] [Accepted: 08/05/2020] [Indexed: 11/08/2022]
Abstract
Background Emerging evidence suggests close domestic proximity of livestock and humans may lead to microbiological contamination of hands, objects, food and water supplies within domestic environments, adversely impacting public health. However, evidence quantifying the relationship between livestock, domestic animals, humans and microbiological contamination of household stored water remains limited. Aim This longitudinal study aimed to examine the relationship between domestic contact with livestock and domestic animals on microbiological contamination of household Point-of-Use (POU) stored drinking water in rural Kenya and assess the influence of choice of faecal indicator on such associations. Methodology A survey was performed in 234 households in Siaya county, Kenya, to observe presence of livestock (cattle, goats, poultry) and domestic animals (cats, dogs) in household compounds, alongside other risk factors for contamination of POU stored drinking water such as sanitation, storage conditions and hygiene practices. Samples from water sources (e.g. piped, spring/wells, boreholes, surface and rainwater) and from POU storage containers were tested for E. coli and intestinal enterococci. Livestock-related risk factors for water contamination were examined through multinomial regression, controlling for confounders. Results Rainwater was the main POU water source and was found to be highly susceptible to contamination. Multivariate analysis showed greater risk of gross (>100 CFU/100 mL) water contamination (with E. coli) for households where goats were observed, and/or where poultry roosted in proximity to stored household water (relative risk RR = 2.71; p = 0.001 and RR = 2.02; p = 0.012 respectively). Presence of a poultry coop was also associated with elevated intestinal enterococci densities (RR = 4.46; p = 0.001). Associations between contamination and livestock risk factors were thus similar for both bacteria groups, but E. coli counts declined more rapidly following collection from surface waters than enterococci counts (p = 0.024). Conclusion The presence of livestock (particularly goats) and poultry within household compounds increases POU water contamination risk, suggesting the need for improved interventions to address cross-contamination within rural domestic settings. Within Siaya county, more effective community education is needed to raise awareness of POU water quality protection, particularly of rainwater. Poultry and goats are risk factors for household stored water contamination. Poultry are risk factors for both enterococci and E. coli contamination. Attenuation of enterococci in household stored water is lower than for E. coli. Residual free chlorine is mostly too low to prevent stored water recontamination.
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Affiliation(s)
- Diogo Trajano Gomes da Silva
- School of Environment and Technology, University of Brighton, Cockcroft Building, Lewes Road, Brighton, BN2 4GJ, UK.
| | - James Ebdon
- School of Environment and Technology, University of Brighton, Cockcroft Building, Lewes Road, Brighton, BN2 4GJ, UK
| | - Joseph Okotto-Okotto
- Victoria Institute for Research on Environment and Development (VIRED) International, P.O. Box 6423-40103, Off Nairobi Road, Rabour, Kisumu, Kenya
| | - Frederick Ade
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Oscar Mito
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Peggy Wanza
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Emmah Kwoba
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Thumbi Mwangi
- Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Weiyu Yu
- School of Geography and Environmental Science, University of Southampton, Building 44, Highfield, Southampton, SO17 1BJ, UK
| | - Jim A Wright
- School of Geography and Environmental Science, University of Southampton, Building 44, Highfield, Southampton, SO17 1BJ, UK
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Trajano Gomes da Silva D, Dias E, Ebdon J, Taylor H. Assessment of recommended approaches for containment and safe handling of human excreta in emergency settings. PLoS One 2018; 13:e0201344. [PMID: 30048542 PMCID: PMC6062132 DOI: 10.1371/journal.pone.0201344] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 07/13/2018] [Indexed: 11/17/2022] Open
Abstract
Ebola and cholera treatment centres (ETC and CTC) generate considerable quantities of excreta that can further the transmission of disease amongst patients and health workers. Therefore, approaches for the safe handling, containment and removal of excreta within such settings are needed to minimise the likelihood of onward disease transmission. This study compared the performance and suitability of three chlorine-based approaches (0.5% HTH, NaDCC and NaOCl (domestic bleach)) and three lime-based approaches (10%, 20% and 30% Ca(OH)2). The experiments followed recent recommendations for Ebola Treatment Centres. Three excreta matrices containing either raw municipal wastewater, or raw municipal wastewater plus 10% or 20% (w/v) added faecal sludge, were treated in 14 litre buckets at a ratio of 1:10 (chlorine solutions or lime suspensions: excreta matrix). The effects of mixing versus non-mixing and increasing contact time (10 and 30 mins) were also investigated. Bacterial (faecal coliforms (FC) and intestinal enterococci (IE)) and viral (somatic coliphages (SOMPH), F+specific phages (F+PH) and Bacteroides fragilis phages (GB-124PH)) indicators were used to determine the efficacy of each approach. Lime-based approaches provided greater treatment efficacy than chlorine-based approaches, with lime (30% w/v) demonstrating the greatest efficacy (log reductions values, FC = 4.75, IE = 4.16, SOMPH = 2.85, F+PH = 5.13 and GB124PH = 5.41). There was no statistical difference in efficacy between any of the chlorine-based approaches, and the highest log reduction values were: FC = 2.90, IE = 2.36, SOMPH = 3.01, F+PH = 2.36 and GB124PH = 0.74. No statistical difference was observed with respect to contact time for any of the approaches, and no statistical differences were observed with respect to mixing for the chlorine-based approaches. However, statistically significant increases in the efficacy of some lime-based approaches were observed following mixing. These findings provide evidence and practical advice to inform safe handling and containment of excreta and ensure more effective health protection in future emergency settings.
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Affiliation(s)
- Diogo Trajano Gomes da Silva
- Environment and Public Health Research Group, School of Environment and Technology, University of Brighton, Brighton, United Kingdom
| | - Edgard Dias
- Department of Sanitary and Environmental Engineering, Faculty of Engineering, Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais, Brazil
| | - James Ebdon
- Environment and Public Health Research Group, School of Environment and Technology, University of Brighton, Brighton, United Kingdom
| | - Huw Taylor
- Environment and Public Health Research Group, School of Environment and Technology, University of Brighton, Brighton, United Kingdom
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