The Water & Health Nexus – Understanding water controls on human health and wellbeing in a drastically changing world
Conveners: Stefan Krause, Christophe Cudennec, Laura Richards

The global pandemic of SARS-CoV-2 has once more highlighted in an agonising way how closely human health and well-being are connected to the global water cycle and safe access to clean and affordable water in order to sustain our needs for food, sanitation and hygiene, as well as energy production, cooling and transport. Unequal access to safe and clean water for hand hygiene has been identified by WHO as a major obstacle for safely handling the risk of the global health crisis unfolding across the world since 2020 and international efforts on interdisciplinary approaches to sustaining fair access to water for sanitation and hygiene are urgently needed to control the course of this, and potential future pandemics.

In addition to representing a precious commodity, water on the Earth’s surface and in the subsurface acts as a transport vector for a wide range of water borne pollutants and pathogens causing diseases such as Cholera, Typhoid, Dysentery or Gardia. Public health concerns regarding these waterborne diseases are high in particular in areas with insufficient or failing water and sanitation infrastructure, with diarrhetic disease representing the second leading cause of death in infants under the age of five and causing higher numbers of infant deaths than malaria, measles and HIV/AIDS together. In addition, drinking water contaminated with critically high concentrations of pollutants such as arsenic, mercury or pesticides represents a global public health concern.

Advances to the mechanistic understanding of water as a transport vector for pathogens and disease are therefore urgently required in order to reduce the risk of pathogen dispersal and associated spread of spread waterborne disease. This involves detailed understanding of how the time dynamic evolution of hydrological connectivity and associated transport flow paths control the spread of waterborne diseases by potentially connecting pathogen sources across and within communities as well as how environmental conditions such as water levels, water temperature and chemistry status control the growth of pathogen concentrations or populations of vector-borne disease transmitting insects (e.g., mosquitos transmitting Dengue, Malaria or West-Nile virus). In addition, optimising the efficiency of water sanitation and hygiene measures and advancing the predictive capacity for epidemiological forecasting will require detailed understanding of hydrometeorological and water pollution pressures on water and sanitation infrastructure as well as adaptation and mitigation management.
The capacity of hydrological models and analysis tools to support predictions of both, pathogen source developments, contaminant activation and their spread is perhaps still underutilised when assessing public health risks associated with waterborne and vestor-borne diseases and pollutants. This session therefore calls for interdisciplinary contributions from the global water and health communities that demonstrate challenges, advances and solutions to:
• The risks posed by waterborne and vector-borne diseases under the influence of global environmental change and resulting pressures on water infrastructure, governance and management
• Water, sanitation and hygiene (WASH) practices, including in the context of conflicts, displacements and temporary settlements
• Wastewater-based epidemiology to provide predictive capacity and early warning of pathogen dispersal and associated public health risks
• Assessments of hydrological controls of health risks related to contaminant source activation and exposure
• Community-based approaches to water governance and safe access to clean water for all
• Economic, technological, behavioural and cultural approaches to educating high-risk communities about water sanitation and hygiene practices
• High-tech to off-grid solutions to providing water treatment opportunities