Multiple water source use in rural Vanuatu: are households choosing the safest option for drinking?

The contribution of decentralized water systems on water quality in Maniema province, DRC

Decentralized water systems (DWS) distribute water in remote African areas. Throughout an intervention in Maniema, Congo, the influence of a DWS performing chlorination in the community's water quality was measured. Additionally, a socio-economic and WASH practices survey was conducted in the communities. Free residual chlorine (FRC) and microbiological contamination were measured; at the borehole, treatment site, distribution points, and households's water containers. In Big Five, water was collected from unimproved sources before DWS construction. Despite that, only 16,6% of households used efficient water treatment methods, resulting in 73% of water stored unsafe for consumption. After construction, household water quality drastically improved, regardless of FRC fluctuations; 93% of samples were classified as low health risk (safe). The renovation guaranteed continuous supply through electro-chlorinators in RVA, where chlorination was intermittent. Water from DWS with adequate chlorine levels prevented microbiological contamination in households for 12 hours. Although economically attractive, the system's sustainability will require future evaluation.

Water quality and microecosystem of water tanks in karst mountainous area, Southwest China

Karst mountainous areas in Southwest China, the world's largest bare karst area, are faced with growing water shortages. Rainwater harvesting plays an important role in alleviating water shortage. However, there remains a substantial gap in the research regarding the water quality of tanks. Water samples were seasonally collected from ten tanks to investigate the physicochemical properties, microbial communities, and their key influencing factors. The result showed that pH, turbidity, chroma, DOC, and CODMn exceeded drinking water guidelines. The alkaline pH value and the deterioration of sensory properties was the main feature of tank water, from which the over-standard rate of the uncleaned water tanks was higher. Moreover, principal component analyses suggested that tank water quality was influenced by human activities, catchment areas, and material cycling processes within the tanks, of which in-tank microbial activities were the most important driving factors in water quality variation. Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and Verrucomicrobia were the predominant bacterial phyla in water tanks. Acinetobacter, Cyanobium-PCC-6307, CL500-29-marine-group, Candidatus-Aquiluna, and Exiguobacterium were the most abundant genera. The bacterial communities were significantly affected by the management practices. Higher relative abundance of Cyanobacteria and lower relative abundance of Proteobacteria was detected in the uncleaned tanks, which was a sign of tank water quality deterioration. The microbial community structure was closely related to the environmental factors. There was evidence that the water quality was affected by the existence of a microecosystem dominated by photosynthetic microorganisms in the water tanks. In addition, Acinetobacter, Enterobacter, Pseudomonas, and Legionella identified as the potential opportunistic pathogenic genera were frequently detected but the relative abundances except Acinetobacter were low in the tanks. Overall, our findings indicated that management style influences water quality and bacterial communities of tank water.

Global potential for harvesting drinking water from air using solar energy

Access to safely managed drinking water (SMDW) remains a global challenge, and affects 2.2 billion people^1,2. Solar-driven atmospheric water harvesting (AWH) devices with continuous cycling may accelerate progress by enabling decentralized extraction of water from air^3-6, but low specific yields (SY) and low daytime relative humidity (RH) have raised questions about their performance (in litres of water output per day)^7-11. However, to our knowledge, no analysis has mapped the global potential of AWH¹² despite favourable conditions in tropical regions, where two-thirds of people without SMDW live². Here we show that AWH could provide SMDW for a billion people. Our assessment-using Google Earth Engine¹³-introduces a hypothetical 1-metre-square device with a SY profile of 0.2 to 2.5 litres per kilowatt-hour (0.1 to 1.25 litres per kilowatt-hour for a 2-metre-square device) at 30% to 90% RH, respectively. Such a device could meet a target average daily drinking water requirement of 5 litres per day per person¹⁴. We plot the impact potential of existing devices and new sorbent classes, which suggests that these targets could be met with continued technological development, and well within thermodynamic limits. Indeed, these performance targets have been achieved experimentally in demonstrations of sorbent materials^15-17. Our tools can inform design trade-offs for atmospheric water harvesting devices that maximize global impact, alongside ongoing efforts to meet Sustainable Development Goals (SDGs) with existing technologies.

Multiple water source use in low- and middle-income countries: a systematic review

The Joint Monitoring Programme (JMP) 2017 Update and Sustainable Development Goals (SDGs) Baselines report classified 71% of the global population as having access to 'safely managed' drinking water. Current global monitoring efforts to track access to safely managed drinking water rely on collecting information on the 'primary' source of drinking water. However, there is evidence that households often rely on multiple sources to meet their water needs in many low- and middle-income countries (LMICs). This systematic review was designed to compile the literature related to the practice of multiple water source use (MWSU) for drinking water in LMICs. A total of 5,318 studies were collected, and after abstract and full-text review, 74 articles were identified for inclusion. Studies reviewed reported from 4 to 100% of the study populations practicing MWSU. Additionally, the practice of supplemental unimproved source use was reported globally, representing households with improved primary source water also accessing unimproved water sources throughout the year. These findings expose gaps in current global water monitoring efforts, revealing potential inflation of reports of 'safe drinking water access' and unaccounted exposure to drinking water from unimproved sources.

Mitigating drought impacts in remote island atolls with traditional water usage behaviors and modern technology

Adaptation to drought is particularly challenging on remote island atolls, such as those found in the Republic of the Marshall Islands (RMI), a nation of 58,000 populating 29 low-lying coral atolls spread over >2 million km². Exposure to consecutive atmospheric hazards, such as meteorological floods and droughts diminish scarce water resources and erode the resilience of island communities. Drought impact mitigation measures must supply emergency drinking water to stricken communities, while simultaneously conserving natural sources in order to reduce their vulnerability to subsequent events. Household surveys (n = 298) and focus group discussions (n = 16) in eight RMI communities revealed that 86% of households have experienced drought and 88% reported using multiple water sources to meet normal household needs. With no surface water and a thin freshwater lens (FWL), rainwater collected from rooftops is the most common household water source. The traditional use of carved hollows in the base of coconut trees to collect rainwater ("Mammaks") appears to have been displaced by large rainwater tanks. However, rationing of rainwater for consumption only during drought was widely reported, with private wells supporting non-consumptive uses. Reverse osmosis (RO) desalination units have provided relief during drought emergencies but concerns have been raised around dependency, maintenance challenges, and loss of traditional water practices. Most notably, RO use has the potential to change the anthroposhpere by adversely affecting the FWL; 86% of RO units were installed at island-centre where excessive pumping can cause upconing, making the FWL brackish. Balancing the introduction of desalination technology to mitigate water shortages with maintenance of traditional water conservation practices to preserve the quantity and quality of the FWL is a promising strategy on island atolls that requires further investigation.

Seroprevalence of antibodies against Chlamydia trachomatis and enteropathogens and distance to the nearest water source among young children in the Amhara Region of Ethiopia

The transmission of trachoma, caused by repeat infections with Chlamydia trachomatis, and many enteropathogens are linked to water quantity. We hypothesized that children living further from a water source would have higher exposure to C. trachomatis and enteric pathogens as determined by antibody responses. We used a multiplex bead assay to measure IgG antibody responses to C. trachomatis, Giardia intestinalis, Cryptosporidium parvum, Entamoeba histolytica, Salmonella enterica, Campylobacter jejuni, enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae in eluted dried blood spots collected from 2267 children ages 0-9 years in 40 communities in rural Ethiopia in 2016. Linear distance from the child's house to the nearest water source was calculated. We derived seroprevalence cutoffs using external negative control populations, if available, or by fitting finite mixture models. We used targeted maximum likelihood estimation to estimate differences in seroprevalence according to distance to the nearest water source. Seroprevalence among 1-9-year-olds was 43% for C. trachomatis, 28% for S. enterica, 70% for E. histolytica, 54% for G. intestinalis, 96% for C. jejuni, 76% for ETEC and 94% for C. parvum. Seroprevalence increased with age for all pathogens. Median distance to the nearest water source was 473 meters (IQR 268, 719). Children living furthest from a water source had a 12% (95% CI: 2.6, 21.6) higher seroprevalence of S. enterica and a 12.7% (95% CI: 2.9, 22.6) higher seroprevalence of G. intestinalis compared to children living nearest. Seroprevalence for C. trachomatis and enteropathogens was high, with marked increases for most enteropathogens in the first two years of life. Children living further from a water source had higher seroprevalence of S. enterica and G. intestinalis indicating that improving access to water in the Ethiopia's Amhara region may reduce exposure to these enteropathogens in young children.

Household Water Storage Management, Hygiene Practices, and Associated Drinking Water Quality in Rural India

Household drinking water storage is commonly practiced in rural India. Fecal contamination may be introduced at the water source, during collection, storage, or access. Within a trial of a community-level water supply intervention, we conducted five quarterly household-level surveys to collect information about water, sanitation, and hygiene practices in rural India. In a random subsample of households, we tested stored drinking water samples for Escherichia coli, concurrently observing storage and access practices. We conducted 9961 surveys and collected 3296 stored water samples. Stored water samples were frequently contaminated with E. coli (69%), and E. coli levels were the highest during the wet season. Most households contributing two or more drinking water samples had detectable E. coli in some (47%) or all (44%) samples. Predictors of stored water contamination with E. coli included consumption of river water and open defecation; consumption of reverse osmosis-treated water and safe water access practices appeared to be protective. Until households can be reached with on-premises continuous safe water supplies, suboptimal household water storage practices are likely to continue. Improvements to source water quality alone are unlikely to prevent exposure to contaminated drinking water unless attention is also given to improving household water storage, access, and sanitation practices.

Climate adaptation for rural water and sanitation systems in the Solomon Islands: A community scale systems model for decision support

Delivering water and sanitation services are challenging in data poor rural settings in developing countries. In this paper we develop a Bayesian Belief Network model that supports decision making to increase the availability of safe drinking water in five flood-prone rural communities in the Solomon Islands. We collected quantitative household survey data and qualitative cultural and environmental knowledge through community focus group discussions. We combined these data to develop our model, which simulates the state of eight water sources and ten sanitation types and how they are affected by season and extreme events. We identify how climate and current practices can threaten the availability of drinking water for remote communities. Modelling of climate and intervention scenarios indicate that water security could be best enhanced through increased rainwater harvesting (assuming proper installation and maintenance). These findings highlight how a systems model can identify links between and improve understanding of water and sanitation, community behaviour, and the impacts of extreme events. The resultant BBN provides a tool for decision support to enhance opportunities for climate resilient water and sanitation service provision.

Geographical inequalities in drinking water in the Solomon Islands

Sustainable Development Goal 6.1 seeks to "by 2030, achieve universal and equitable access to safe and affordable drinking water", which is challenging particularly in Small Island Developing States (SIDS) and Pacific Island Countries (PIC). We report drinking water sources and services in the Solomon Islands and examine geographical inequalities. Based on two quantitative baseline datasets of n = 1,598 rural and n = 1,068 urban households, we analyzed different drinking water variables (source type, collection time, amount, use, perceived quality, storage, treatment) and a composite index, drinking water service level. We stratified data by urban and rural areas and by province, mapped, and contextualized them. There are substantive rural-urban drinking water inequalities in the Solomon Islands. Overall, urban households are more likely to: use improved drinking water sources, need less time to collect water, collect more water, store their water more safely, treat water prior to consumption, perceive their water quality as better and have an at least basic drinking water service than rural households. There are also provincial and center-periphery inequalities in drinking water access, with more centrally located provinces using piped water supplies and more distant and remote provinces using rainwater and surface water as their primary source. There are also inter-national inequalities. Out of all PICs, the Solomon Islands have among the lowest access to basic drinking water services: 92% of urban and 55% of rural households. Of all SIDS, PICs are least serviced. This study shows that drinking water inequality is a critical issue, and highlights that all identified dimensions of inequality - rural-urban, provincial, center-periphery and inter-national - need to be explicitly recognized and addressed and included in pro-equity monitoring, policy and programming efforts by the Solomon Islands Government and stakeholders to reduce inequalities as per the Agenda 2030.

Evaluating the Level of the Household Water Service Provided by a Private Water Enterprise in Ghana

Innovative service delivery models are attempting to more consistently provide clean water to communities in developing countries. It is imperative that these approaches be evaluated for their performance in these contexts while understating potential consequences. A private service delivery model in Ghana utilizing solar-powered water treatment, circuit rider principles, pre-paid metering, and a district-wide approach was assessed for three years. A quasi-experimental design used key informant surveys, household surveys, and water quality testing to investigate the service received by households under various management schemes. Service indicators were compared using logistic regression analysis. Private customers were shown to have significantly improved quality, annual reliability, and satisfaction ratings (p < 0.05) compared with control households, while maintaining the quantity of water collected. However, private customers were more reliant upon multiple water sources to meet domestic needs and suffered from lower affordability scores. About 38% of households used private water services, with no significant relationship with socioeconomic class. It is important for policy-makers and implementers to understand that some people will be unwilling or unable to take advantage of this model, and a transition from free improved sources to paid piped schemes will likely require a period of supporting both systems in order to reach everyone.

What are the main factors influencing the presence of faecal bacteria pollution in groundwater systems in developing countries?

Groundwater is the major source of drinking water in most rural areas in developing countries. This resource is threatened by the potential presence of faecal bacteria coming from a variety of sources and pollution paths, the former including septic tanks, landfills, and crop irrigation with untreated, or insufficiently treated, sewage effluent. Accurately assessing the microbiological safety of water resources is essential to reduce diseases caused by waterborne faecal exposure. The objective of this study is to discern which are the most significant sanitary, hydrogeological, geochemical, and physical variables influencing the presence of faecal bacterial pollution in groundwater by means of statistical multivariate analyses. The concentration of Escherichia coli was measured in a number of waterpoints of different types in a rural area located in the coast of Kenya, assessing both a dry and a wet season. The results from the analyses reaffirm that the design of the well and their maintenance, the distance to latrines, and the geological structure of the waterpoints are the most significant variables affecting the presence of E. coli. Most notably, the presence of faecal bacteria in the study area correlates negatively with the concentration of ion Na⁺ (being an indirect indicator of fast recharge in the study site), and also negatively with the length of the water column inside the well.

Evaluation of groundwater quality in Sivas province (Turkey) using water quality index and GIS-based analytic hierarchy process

The main purpose of the research was to evaluate the groundwater quality in wet and dry seasons of the study area and determine the areas with high water quality. First, diagrams commonly used in groundwater quality assessment were prepared. Water quality index (WQI) values were calculated by using water quality parameters, spatial distribution maps of WQI and water quality parameters were created by using Geographical Information System (GIS). Groundwater quality mapping was performed with the help of GIS-based analytic hierarchy process. The obtained findings showed that, 91.66% and 77.07% of groundwater samples respectively received at wet and dry seasons have been suitable for drinking. Groundwater quality of around Sivas city center has been rated with 'excellent' water quality. The most important factors affecting the water quality of the research area were the lithological characteristics of the area and agricultural uses. TDS, NO₃, SO₄, Cr and As are the parameters that negatively affect water quality.

Faecal contamination of groundwater in rural Vanuatu: prevalence and predictors

Groundwater is an important source of water for coastal communities in Pacific Island Countries. This study assessed the prevalence and predictors of faecal contamination in groundwater sources across 11 islands in Vanuatu. Escherichia coli was detected in 49% of sources and E. coli concentration exceeded 10 MPN (most probable number)/100 mL for 23% of sources. When adjusting for other variables, the detection of E. coli was significantly associated with severe pump stand corrosion, suggestive of contaminated run-off directly entering boreholes. E. coli concentration >10 MPN/100 mL was also significantly associated with: (i) hand-dug wells (as compared to drilled boreholes); (ii) severe pump stand corrosion; (iii) water points underlain by volcanic rocks (as compared to coral limestone); and (iv) rainfall in the previous 24 h. Encasing pump stands in concrete - as some communities had done - was found to have a significant protective effect. While baseline statistics for Sustainable Development Goal target 6.1 suggest that 87% of Vanuatu's rural population have access to at least a basic (improved) water source, the results from this study point to extensive microbial water quality concerns linked to degraded water supply infrastructure in need of rehabilitation.

Groundwater as a Source of Drinking Water in Southeast Asia and the Pacific: A Multi-Country Review of Current Reliance and Resource Concerns

Groundwater is widely acknowledged to be an important source of drinking water in low-income regions, and it, therefore, plays a critical role in the realization of the human right to water. However, the proportion of households using groundwater compared with other sources is rarely quantified, with national and global datasets more focused on facilities—rather than resources—used. This is a significant gap in knowledge, particularly in light of efforts to expand water services in line with the inclusive and integrated agenda of the Sustainable Development Goals. Understanding the prevalence of groundwater reliance for drinking is critical for those involved in water services planning and management, so they can better monitor and advocate for management of water resources that supports sustainable services for households. This paper contributes data that can be used to strengthen the integration of resource considerations within water service delivery and inform the work of development partners supporting this area. We approach this issue from two perspectives. Firstly, we collate data on the proportion of households using groundwater as their primary drinking water source for 10 Southeast Asian and Pacific nations, finding an average of 66% (range of 17–93% for individual countries) of households in urban areas and 60% (range of 22–95%) of households in rural areas rely on groundwater for drinking. Together, these constitute 79% of the total population across the case study countries. Secondly, we review current and emerging groundwater resource concerns within each country, using a systems thinking approach to assess how groundwater resource issues influence household water services. Findings support the case for governments and development agencies to strengthen engagement with groundwater resource management as foundational for achieving sustainable water services for all.

Factors Associated with Water Service Continuity for the Rural Populations of Bangladesh, Pakistan, Ethiopia, and Mozambique

Access to continuous water supply is key for improving health and economic outcomes in rural areas of low- and middle-income countries, but the factors associated with continuous water access in these areas have not been well-characterized. We surveyed 4786 households for evidence of technical, financial, institutional, social, and environmental predictors of rural water service continuity (WSC), defined as the percentage of the year that water is available from a source. Multiple imputed fractional logistic regression models that account for the survey design were used to assess operational risks to WSC for piped supply, tube wells, boreholes, springs, dug wells, and surface water for the rural populations of Bangladesh, Pakistan, Ethiopia, and Mozambique. Multivariable regressions indicate that households using multiple water sources were associated with lower WSC in Bangladesh, Pakistan, and Mozambique. However, the possibility must be considered that households may use more than one water source because services are intermittent. Water scarcity and drought were largely unassociated with WSC, suggesting that service interruptions may not be primarily due to physical water resource constraints. Consistent findings across countries may have broader relevance for meeting established targets for service availability as well as human health.