Geographical inequalities in drinking water in the Solomon Islands

Invisible struggles: WASH insecurity and implications of extreme weather among urban homeless in high-income countries - A systematic scoping review

This paper aims to provide a deeper understanding of the water-, sanitation- and hygiene (WASH)-related insecurities that people experiencing homelessness in urban areas of high-income countries (HIC) are facing, and how these insecurities are further complicated during extreme weather events. While limited recent research has looked into WASH among people experiencing homelessness in HICs, and while some work has considering the implications of climate change on WASH and health, the nexus of WASH, extreme weather events and homelessness in HICs have not been studied thus far. We conducted the first systematic scoping review of peer-reviewed literature on this nexus, which is understudied and marked by complexity, involving a range of systems and forms of impact. A total of 50 publications were included in our analysis. We found that public facilities like drinking water fountains, toilets, handwashing facilities, and showers are scarce, frequently unavailable, often pose safety and cleanliness issues, and access to non-public facilities may be cost-prohibitive for homeless populations. Consequently, people experiencing homelessness, including those sleeping rough, in encampments, or shelters, are often forced to limit drinking water consumption, forego healthy hygiene behaviours, and resort to open urination and defecation, all of which carry health risks. Extreme weather events, like heatwaves, extreme cold, heavy rain and flooding exacerbate challenges for people experiencing homelessness, further complicating their access to WASH, and reducing the ability of service providers to deliver extra relief, creating a dual WASH and health burden. Our review highlights that the Human Right to Water and Sanitation is not met for people experiencing homelessness in urban areas of high-income countries, with women emerging as one of the most vulnerable subgroups. It reveals that the impact of certain WASH issues (e.g. drinking water) on homeless populations are better understood than others (e.g. waste), and, similarly, the effects of certain extreme weather events (e.g. heatwaves) on the health and WASH conditions of people experiencing homelessness are better understood than others (e.g. flooding). Data gaps and the lack of information on limited WASH access and health circumstances of people experiencing homelessness, further minimize their representation and consequently impose obstacles to improve their situation. Based on our analysis, we established a framework which operationalizes the nexus of WASH, extreme weather events and homelessness. This framework improves our understanding of the underlying complexities at the intersection of these three issues and provides a foundation for enhanced preparedness and health-oriented planning.

Spatial and socioeconomic inequalities in the access to safe drinking water in Peruvian households

Access to safe drinking water has increased in Peru over the last decades, from 47% (2008) to 52% (2018). Nevertheless, such access would differ according to socioeconomic and regional factors. Thus, this study aimed to assess the socioeconomic inequality in the access to safe drinking water and identify its spatial distribution. We conducted a cross-sectional study based on the secondary data analysis of the 2021 Peruvian Demographic and Health Survey. Access to safe drinking water was a dummy variable categorised as safe if the residual chlorine concentration was ≥0.5 mg/L. Nationwide, 29.22% of households had access to safe drinking water. A pro-rich inequality in access to safe drinking water was observed. The spatial distribution was clustered. Significant hotspots were found in the south and centre of the country; however, cold spots were found in most areas. SaTScan analysis identified 32 and 63 significant clusters at high and low risks of having access to safe drinking water, respectively. In conclusion, approximately one out of four Peruvian households has access to safe drinking water, which was mostly concentrated among the wealthier households. Intra- and interdepartmental inequalities in access to safe drinking water were found, with several high-risk clusters.

A decision support tool to place drinking water sources in rural communities

Installing more drinking water sources is a promising way to achieve the 6th sustainable development goal "Clean water and sanitation" in rural communities. A key parameter for the installation of new water pumps is geographical position, because the number of people who could gain access to drinking water depends on the location of the pump. To improve the choice of the most appropriate location, we propose a decision support tool to place a new drinking water source in a rural community. This tool relies on four complementary maps, which are obtained from GPS data, survey data, and a water source choice model. The first map shows the spatial distribution of the households and of the existing water sources in the village. The three remaining maps present the following quantities as a function of the position of a new drinking water source in the village: the number of users of the new drinking water source, the improvement of drinking water access, and the daily water demand per capita at the new drinking water source. The decision support tool is applied to a village in Burkina Faso. Results indicate that using the proposed method could allow eight times more people to gain access to drinking water in comparison to a random positioning of the new drinking water source. The original contribution of this work is, first, the consideration of existing water sources in the village, as well as seasonality. Second, we base our analysis on a water source choice model, which accounts for water quality in addition to the distance to the water source. Third, we consider the variability of the water volume collected by the households throughout the village. The developed tool is generic, transferable to other villages and useful for various decision-making entities (e.g. local authorities and non-governmental organizations).

Water quality challenges associated with industrial logging of a karst landscape: Guadalcanal, Solomon Islands

Human disturbance of karst landscapes in tropical volcanic islands present a unique challenge for understanding sediment transport to the coastal zone. Here we present the first evidence of urban drinking water quality impacts from industrial logging in the Solomon Islands. Despite only 6% of the Honiara's drinking water catchment being disturbed by logging, rhodamine dye tracers demonstrated complex karst sinkholes that led to high suspended sediment concentrations being transported from neighbouring Kovi catchment into the Kongulai water supply offtake point for Honiara. This has resulted in the exceedance of practical treatment thresholds of 20 NTU 9.5% of the time, leading to water supply for the majority of Honiara's residents being unavailable for 58 days in 2019. This work highlights the cost-benefit disparity between industrial logging yielding minimal short-term economic yields in comparison to on-going broader impacts of increased coastal sediment transport while restricting water supply to a developing nation's capital.

Preprocessing alternatives for compositional data related to water, sanitation and hygiene

The Sustainable Development Goals (SDGs) 6.1 and 6.2 measure the progress of urban and rural populations in their access to different levels of water, sanitation and hygiene (WASH) services, based on multiple sources of information. Service levels add up to 100%; therefore, they are compositional data (CoDa). Despite evidence of zero value, missing data and outliers in the sources of information, the treatment of these irregularities with different statistical techniques has not yet been analyzed for CoDa in the WASH sector. Thus, the results may present biased estimates, and the decisions based on these results will not necessarily be appropriate. In this article, we therefore: i) evaluate methodological imputation alternatives that address the problem of having either zero values or missing values, or both simultaneously; and ii) propose the need to complement the point-to-point identification of the WHO/UNICEF Joint Monitoring Program (JMP) with other robust alternatives, to deal with outliers depending on the number of data points. These suggestions have been considered here using statistics for CoDa with isometric log-ratio (ilr) transformation. A selection of illustrative cases is presented to compare performance of different alternatives.