Synthesis and Characterization of Porous Hydroxyapatite Ceramics for Batch and Column Treatment of Fluoride-Impacted Ground Water

Nearly 200 million people worldwide are exposed to drinking water with elevated levels of naturally occurring fluoride. The World Health Organization recommends a maximum fluoride concentration of 1.5 mg/L in drinking water above which it can cause dental fluorosis and skeletal fluorosis. This research focused on developing a low-cost adsorbent to overcome the limitations of existing fluoride removal materials. Porous hydroxyapatite ceramic adsorbents were synthesized and characterized to study the effect of size of hydroxyapatite grains, pore size and pore volume on fluoride removal. The maximum fluoride adsorption capacity, determined by fitting isotherm data to Langmuir parameters, was 18 mg/g which is 3 to 4 times higher than widely used adsorbents such as activated alumina and bone char. This ceramic adsorbent was regenerated with 1 M NaOH and retained 70% of its original adsorption capacity for up to 4 adsorption cycles. Further, it had good selectivity for fluoride; of several ions evaluated, only chloride competed for adsorbent sites at concentrations commonly found in groundwater. The kinetic performance of this adsorbent was tested through batch kinetic tests and continuous-flow columns studies. Equilibrium fluoride concentration and time to reach equilibrium were found to be independent of adsorbent size, suggesting that the effective intraparticle diffusivity is independent of adsorbent size. Continuous-flow columns studies revealed that the breakthrough curves, plotting the effluent fluoride concentration versus number of bed volumes treated, were dependent on flow rate. Interrupting the column flow led to a decrease in effluent concentration suggesting that mass transport was limited by intraparticle diffusion i.e. diffusion of fluoride ions into the pores and along the surface of the pores inside the porous ceramic. On a bed volume basis, the ceramic performed six to seven times better than activated alumina and bone char. The cost of manufacturing this media was found to be approximately $1.6 per kg, estimated from bulk raw material costs and electricity consumption, which is comparable to the cost of commercially available activated alumina, demonstrating that this material has the potential to be cost-effective in resource-limited settings

Assessing the climate resilience of community-managed water supplies in Ethiopia and Nepal

Understanding the resilience of water supplies to climate change is becoming an urgent priority to ensure health targets are met. Addressing systemic issues and building the resilience of community-managed supplies, which serve millions of people in rural LMIC settings, will be critical to improve access to safe drinking water. The How Tough is WASH (HTIW) framework to assess resilience was applied to community-managed water supplies in Ethiopia and Nepal to assess the effectiveness of this framework in field conditions. The resilience of these water supplies was measured along six domains—the environment, infrastructure, management, institutional support, community governance and supply chains—that can affect how they respond to climate change effects. We found that the HTIW framework provided an objective measure of resilience and could be used to rank water supplies in order of priority for action. We also found that systemic issues could be identified. The tools and methods used in the framework were easy to deploy by field research teams. The water supplies studied in Ethiopia and Nepal had low to moderate resilience to climate change. Service management and institutional support were weak in both countries. The data from Ethiopia and Nepal suggests that many water supplies in rural and small-town communities are unlikely to be resilient to future climate change without increased investment and support. The use of simple frameworks such as HTIW will be important in supporting decisions around such investments by identifying priority communities and actions

Applying a WASH risk assessment tool in a rural South African setting to identify risks and opportunities for climate resilient communities

Climate change threatens the health and well-being of populations. We conducted a risk assessment of two climate-related variables (i.e., temperature and rainfall) and associated water, sanitation and hygiene (WASH)-related exposures and vulnerabilities for people living in Mopani District, Limpopo province, South Africa. Primary and secondary data were applied in a qualitative and quantitative assessment to generate classifications of risk (i.e., low, medium, or high) for components of hazard/threat, human exposure, and human vulnerability. Climate-related threats were likely to impact human health due to the relatively high risk of waterborne diseases and WASH-associated pathogens. Vulnerabilities that increased the susceptibility of the population to these adverse outcomes included environmental, human, physical infrastructure, and political and institutional elements. People of low socio-economic status were found to be least likely to cope with changes in these hazards. By identifying and assessing the risk to sanitation services and water supply, evidence exists to inform actions of government and WASH sector partners. This evidence should also be used to guide disaster risk reduction, and climate change and human health adaptation planning.DATA AVAILABILITY STATEMENT : The laboratory sample data are available from the National Health Laboratory Services. All hazard-related data were extracted from publicly available manuscripts as cited in the text.The South African Medical Research Council and the National Research Foundation. The A.P.C. was funded by the South African Medical Research Council.https://www.mdpi.com/journal/ijerphGeography, Geoinformatics and Meteorolog

Environmental hygiene in outdoor food markets in Africa:a scoping review

Outdoor food markets represent important locations where foodborne illnesses and other infectious diseases can spread. Countries in Africa face particular challenges given the importance of these markets in food supply and low rates of access to safely managed water and sanitation. We undertook a scoping review of evidence related to disease transmission in food markets in sub-Saharan Africa, North Africa and identified 46 papers for data extraction and synthesis. Vendor behaviour or awareness was reported in the majority of papers and about half reported on market infrastructure. Fewer studies have been reported on regulatory environments or food contamination. Studies on water supply, sanitation and handwashing facilities focused on the presence of services and did not evaluate quality, thus conclusions cannot be drawn on service adequacy. Studies of vendor behaviour were primarily based on self-reporting and subject to bias. Most studies reported high levels of vendor awareness of the need for hygiene, but where observations were also conducted, these showed lower levels of behaviours in practice. Our findings suggest that there are limited studies on environmental hygiene in outdoor food markets and this is an area warranting further research, including into the quality of services and addressing methodological weaknesses

Climate Resilience of town water utilities in Eastern Ethiopia

Climate change threatens the safety of water supplies globally, but small water supplies in rapidly growing and urbanizing towns in low- and middle-income countries are especially at risk. Despite the efforts of the Government of Ethiopia, research shows that that small-town water utilities in Ethiopia are poorly equipped to prioritize developing and maintaining climate-resilient water services. We applied the How tough is WASH framework for climate resilient water supplies to ten town water utilities in Eastern Ethiopia to identify their strengths and weaknesses in preparing for climate change. We found reports of weak institutional support from service authorities and exclusion of climate risk management from trainings, which cascades down to service providers in the form of lack of emergency response, inadequate staffing and financial mismanagement. This is consistent with previous studies on sustainability of town water utilities and highlights the applicability of this tool into existing monitoring frameworks that have been proposed for town water utilities in Ethiopia. We also modified the How tough is WASH framework to capture these findings and better reflect the complexity of a utility-managed piped water supply