Moving towards transformational WASH
Authors: Josh Kearns
Journal: The Lancet Global Health (2019)

As noted by the Lancet Commission on pollution and health,1Landrigan PJ Fuller R Acosta NJR et al.The Lancet Commission on pollution and health.Lancet. 2018; 391: 462-512Summary Full Text Full Text PDF PubMed Scopus (1280) Google Scholar the anthropogenic release of chemicals from industry and agriculture and the breakdown of consumer waste constitutes a major threat to water and global public health. Chemical pollution is severe and increasing in developing countries, where chemical substances are produced, used, and disposed of in an unregulated manner. The global public health consequences of pollution are similar to or greater than those of widespread infectious diseases, such as HIV/AIDS, tuberculosis, and malaria.1Landrigan PJ Fuller R Acosta NJR et al.The Lancet Commission on pollution and health.Lancet. 2018; 391: 462-512Summary Full Text Full Text PDF PubMed Scopus (1280) Google Scholar, 2Landrigan PJ Fuller R Pollution, health and development: the need for a new paradigm.Rev Environ Health. 2016; 31: 121-124Crossref PubMed Scopus (2) Google Scholar However, chemicals have so far been neglected by the water, sanitation, and hygiene (WASH) development sector. Amy Pickering and colleagues3Pickering AJ Null C Winch PJ et al.The WASH Benefits and SHINE trials: interpretation of WASH intervention effects on linear growth and diarrhoea.Lancet Glob Health. 2019; 7: e1139-e1146Summary Full Text Full Text PDF PubMed Scopus (89) Google Scholar analyse the recent WASH Benefits trials and the Sanitation, Hygiene, Infant Nutrition Efficacy (SHINE) trial, in Bangladesh, Kenya, and Zimbabwe, which revealed that household WASH interventions are unlikely to reduce diarrhoea or improve child growth. One explanation for why WASH interventions have failed to produce health benefits is that WASH interventions control for pathogens but not chemicals. Exposure to many synthetic chemicals can dysregulate immune function in ways that lead not only to increased vulnerability to non-communicable diseases, such as cancer, but also to greater susceptibility to pathogens and reduced effectiveness of vaccinations against infectious diseases.4Winans B Humble MC Lawrence BP Environmental toxicants and the developing immune system: a missing link in the global battle against infectious disease?.Reprod Toxicol. 2011; 31: 327-336Crossref PubMed Scopus (76) Google Scholar, 5Erickson BE Linking pollution and infectious disease: chemicals and pathogens interact to weaken the immune system, reduce vaccine efficacy, and increase pathogen virulence.Chem Eng News. 2019; 97: 28-33Google Scholar For example, immunotoxicity has been demonstrated for several compound classes, including halogenated organics, plasticisers such as phthalates and bisphenol-A, numerous pesticides including atrazine and chlordane, flame retardants, and per-fluoroalkyl and poly-fluoroalkyl substances (PFAS).4Winans B Humble MC Lawrence BP Environmental toxicants and the developing immune system: a missing link in the global battle against infectious disease?.Reprod Toxicol. 2011; 31: 327-336Crossref PubMed Scopus (76) Google Scholar, 5Erickson BE Linking pollution and infectious disease: chemicals and pathogens interact to weaken the immune system, reduce vaccine efficacy, and increase pathogen virulence.Chem Eng News. 2019; 97: 28-33Google Scholar Therefore, WASH interventions that do not control for chemicals in addition to pathogens might fail to achieve gains in health indicators associated with waterborne disease. The WASH sector has yet to recognise and grapple with the challenge of mitigating threats to health from chemical toxicants in water. For example, Pickering and colleagues make recommendations for improving WASH interventions, but do not mention chemicals. There is an urgent need for WASH to move beyond the current, limited focus on microbial pathogens, towards a holistic approach to water and health in developing countries that takes chemicals into account. As a step to address this challenge, some colleagues and I have formed the WASH-Toxics Working Group. I declare no competing interests. The WASH Benefits and SHINE trials: interpretation of WASH intervention effects on linear growth and diarrhoeaChild stunting is a global problem and is only modestly responsive to dietary interventions. Numerous observational studies have shown that water quality, sanitation, and handwashing (WASH) in a household are strongly associated with linear growth of children living in the same household. We have completed three randomised efficacy trials testing improved household-level WASH with and without improved infant and young child feeding (IYCF) on stunting and diarrhoea in Bangladesh, Kenya, and Zimbabwe. Full-Text PDF Open AccessMoving towards transformational WASH – Authors' replyWe agree with Karen Levy and Joseph Eisenberg that observational studies of water, sanitation, and hygiene (WASH) interventions with carefully designed counterfactuals can play a valuable role in generating evidence on effectiveness, particularly in urban settings. Randomised controlled trials for community-level WASH infrastructure interventions are not always feasible in urban settings, because of the political and logistical constraints of defining treatment and control groups; strong observational designs could help fill the gap. Full-Text PDF Open AccessMoving towards transformational WASHThe observational reanalysis by Amy Pickering and colleagues (August, 2019)1 of controls in the WASH Benefits trials and the Sanitation, Hygiene, Infant Nutrition Efficacy (SHINE) trial is a compelling reminder that observational studies are susceptible to confounding bias. However, we should not discount the value of observational studies in global health research, because ethical and logistical issues often limit the feasibility of randomised control trials (RCTs) and observational studies are a requisite precursor to trials. Full-Text PDF Open Access