The world is not on track to meet Sustainable Development Goal 6.1 to provide universal access to safely managed drinking water by 2030. Removal of priority microbial contaminants by disinfection is one aspect of ensuring water is safely managed. Passive chlorination (also called in-line chlorination) represents one approach to disinfecting drinking water before or at the point of collection (POC), without requiring daily user input or electricity. In contrast to manual household chlorination methods typically implemented at the point of use (POU), passive chlorinators can reduce the user burden for chlorine dosing and enable treatment at scales ranging from communities to small municipalities. In this review, we synthesized evidence from 27 evaluations of passive chlorinators (in 19 articles, 3 NGO reports, and 5 theses) conducted across 16 countries in communities, schools, health care facilities, and refugee camps. Of the 27 passive chlorinators we identified, the majority (22/27) were solid tablet or granular chlorine dosers, and the remaining devices were liquid chlorine dosers. We identified the following research priorities to address existing barriers to scaled deployment of passive chlorinators: (i) strengthening local chlorine supply chains through decentralized liquid chlorine production, (ii) validating context-specific business models and financial sustainability, (iii) leveraging remote monitoring and sensing tools to monitor real-time chlorine levels and potential system failures, and (iv) designing handpump-compatible passive chlorinators to serve the many communities reliant on handpumps as a primary drinking water source. We also propose a set of reporting indicators for future studies to facilitate standardized evaluations of the technical performance and financial sustainability of passive chlorinators. In addition, we discuss the limitations of chlorine-based disinfection and recognize the importance of addressing chemical contamination in drinking water supplies. Passive chlorinators deployed and managed at-scale have the potential to elevate the quality of existing accessible and available water services to meet "safely managed" requirements.

Associations between different forms of malnutrition and environmental conditions, including water, sanitation and hygiene (WASH), may contribute towards persistently poor child health, growth and cognitive development. Experiencing poor nutrition in utero or during early childhood is furthermore associated with chronic diseases later in life. The primary responsibility for provision of water and sanitation, as a basic service and human right, lies with the State; however, a number of stakeholders are involved. The situation is most critical in sub-Saharan Africa (SSA), where, in 2015, 311 million people lacked a safe water source, and >70% of SSA populations were living without adequate sanitation. The aim of this paper was to conduct a systematic review to investigate the state of literature concerned with WASH and its association with nutritional status, and governance in children from birth to 5 years of age in SSA. Articles were sourced from PubMed Central, Science Direct and ProQuest Social Science databases published between 1990 and 2017. The PRISMA Statement was utilised and this systematic review is registered with PROSPERO (CRD42017071700). The search terms returned 15,351 articles for screening, with 46 articles included. This is indicative of a limited body of knowledge; however, the number of publications on this topic has been increasing, suggesting burgeoning field of interest. Targeted research on the governance of WASH through the identification of the various role players and stakeholders at various levels, while understanding the policy environment in relation to particular health-related outcomes is imperative to address the burden of child undernutrition.

Aflatoxin exposure has been proposed to affect child height-for-age. The following hypothesized associations were tested in Guatemala: (1) aflatoxin (B₁, B₂, G₁, G₂) exposure and environmental enteric dysfunction (EED) and child height-for-age z-score; and (2) aflatoxin exposures and subsequent symptoms of aflatoxins. Maize consumption data, health data, and samples of maize from households were collected from mothers and their children – under five – in October 2016 (n = 320) and February 2017 (n = 120). Maize samples were tested for aflatoxin levels and maize consumption data were used to compute an aflatoxin exposure level. Results suggest that there was a significant negative correlation between the putative aflatoxin exposure level and child height-for-age z-score (−0.073, p = 0.030), but not for EED. Furthermore, aflatoxin exposure was significantly correlated with aflatoxin symptoms only at the same time point (0.123, p = 0.026). These results support the potential need for engineered solutions to household aflatoxin transmission problems in rural communities of Guatemala.

Recent literature suggests that intestinal microbiome may play a mediating role between aflatoxin exposure and the height-for-age of children. We tested the hypothesis that among children in Guatemala, aflatoxin exposure was associated with intestinal microbiome dysbiosis and lower height-for-age. De-identified data were acquired from local health officials for 35 children who attended a health clinic in Totonicapán, Guatemala, and had potentially been exposed to aflatoxin through their maize-based food supply. Microbial differences were assessed for children grouped by height, diarrhea, age, and aflatoxin exposure. Furthermore, two subgroups were identified—one healthy (n = 12) and one unhealthy/dysbiotic (n = 9)—based upon clustering of the children's microbiomes and morbidity data. Odds ratios were computed to assess the likelihood of a child having a healthy or dysbiotic microbiome based on the classification of height, diarrhea, age, or aflatoxin exposure. The results of the study supported significant differences in beta diversity between the intestinal microbiomes of children who were shorter (less than or equal to −2.54 standard deviation; SD) versus taller (greater than −2.54 SD), those who were older (>14 months of age) versus younger (10 ng of aflatoxin/kg of body weight/day had 24 times higher odds of having a dysbiotic intestinal microbiome. The results build upon available literature and support the need for more in-depth studies concerning the interactions among aflatoxin exposure, the intestinal microbiome, and child stunting.

Promoting access to safe drinking water or access to nutritious food, each independently contribute uniquely to positive gains in human health. Nexus analysis—a systems-based approach to study interconnection and interdependence—provides a framework to expose interactions and interventions in linked food–water systems. Interactions result in unintentional changes in efficacy or toxicity creating poorer-than-expected health outcomes while synergistic interventions targeting both “water, sanitation, and hygiene” as well as “food security, nutrition, and safety” yield greater-than-anticipated improvements in health and wellness. Herein, we describe a case study of linked food–water systems, where discovery, integration, application, and the scholarship of teaching and learning, collectively enhanced child health through convergence research—a transdisciplinary approach to solve a compelling and specific problem. The method integrates five techniques predominant in the field of health care, including: (1) community-based participatory research, (2) structured reviews, (3) mixed methods, (4) structural equation modeling, and (5) interprofessional education—at multiple study sites in east Africa, Guatemala, Brazil, and South Africa. The compelling problem explored is, “the lack of an overarching framework to achieve improvements in interdisciplinary environmental health practice and policy,” to ultimately solve specific problems such as, “the eradication of childhood stunting.” Results demonstrate that convergence research improves environmental health practice and policy by exposing insights to be measured, validated, and disseminated.