A planetary health model for reducing faecal exposure in informal settlements

Writing credit: RISE Program

Professor Karin Leder, co-Head of the School’s Infectious Diseases Epidemiology Unit, is senior author on a significant new paper from the RISE program, one of the University’s ambitious multi-disciplinary raft of projects, which aims to improve water and sanitation in informal settlements across South East Asia.

The RISE baseline findings from Indonesia have generated a new model of the connections between human health and the environment. The intense interactions between people, animals and environmental systems in urban informal settlements compromise human and environmental health. While the full scope of risks and exposure pathways between human health and the environment are uncertain, a new paper co-authored by 40 RISE researchers presents a new planetary health model of health and the environment.

‘The risk factors that come with poor environmental conditions should not be considered alone, as it can be misleading in characterising a settlement’s environment and population,’ explains Ruzka Taruc, one of the paper’s co-lead authors. ‘We examine the inter-connections between the built environment, socio-economic wellbeing, human health and the ecological environment, which will pave ways to better design and monitor interventions.’

Colleagues at Monash University in Melbourne, Australia and Hasanuddin University in Makassar, Indonesia, developed the model by drawing on baseline findings from the RISE trial in Makassar. It comprehensively accounts for a wider range of variables affecting health in urban informal settlements than conventional exposure models that inform conventional water and sanitation approaches.

‘We know that reducing faecal-oral contamination will help children improve their development and gastrointestinal health. But traditional household-scale Water, Sanitation and Hygiene (WASH) models and interventions are not fit-for-purpose in high-density informal settlements, due to the pervasive exposure to pathogens, pollutants and disease in the communal environment outside the home,’ says Professor Karin Leder, the paper’s senior author, and Director of Research for RISE.

Leder says there is increasing awareness of the need for a framework involving social, demographic and environmental factors that can better assess the effectiveness of water and sanitation interventions on reducing faecal-oral transmission among children. From a practical perspective then, interventions are needed that address water and sanitation needs from an overall environmental and human health perspective, using a systems view.

‘The data we collected over one year from 12 informal settlements across Makassar confirms poor health: among children under the age of five, almost half were experiencing stunting (44.3%), and almost half were underweight (41.1%),’ says Taruc. ‘But the planetary health model pushes further—it empirically aims to link poor health to environmental exposure to pathogens, pollutants and disease vectors in water, food, air and soil.’

Initial results show high rates of potential risky exposures from swimming in waterways, eating uncooked produce, and eating soil or dirt, along with exposure to flooding and livestock.

Leder explains that ‘a planetary health model points us to innovative interventions that address environmental and human health at a range of scales, not only the individual- or household-scale but also the settlement and wider precinct scales.’

This first year of data is the critical point of reference against which RISE will assess the results of human and environmental sampling post-intervention (construction of sustainable water and sanitation infrastructure in the program’s 12 participating informal settlements in Makassar). RISE will continue conducting intensive sampling and surveys with residents once the intervention is built for a period of two years to understand the impact of the intervention and further refine this model.

Read more

French M, Barker F, Taruc R, et al. A planetary health model for reducing exposure to faecal contamination in urban informal settlements: Baseline findings from Makassar, Indonesia. Environment International. 2021 Oct;155:106679. doi: 10.1016/j.envint.2021.106679.

About the RISE program

The RISE program seeks to develop a new approach to achieve Sustainable Development Goal 6: clean water and sanitation for all.

More than one billion people living in informal settlements globally. Over two billion live without basic sanitation. Climate change and rapid population growth in these settlements exacerbate water and sanitation challenges. Polluted water supplies and inadequate sanitation are leading causes of disease in these communities.

RISE aims to provide research-based evidence that a localised, water-sensitive approach to revitalising informal settlements can deliver sustainable, cost-effective health and environmental improvements, paving the way for further deployments in the region and globally.

Working with communities, governments, local leaders and partner institutions, RISE is co-designing and constructing sustainable water and sanitation infrastructure, such as constructed wetlands and biofiltration gardens, to strengthen the whole-of-life water and sanitation cycle in informal settlements.

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