Wastewater Provides A Planet-wide Laboratory For The Study Of Human Health
Of the many contemporary conveniences often taken for granted in developed countries, modern sanitation may be among the most important. A new study suggests that wastewater infrastructure may provide societal benefits far beyond the dramatic improvements in community hygiene.
The research highlights a technique known as Wastewater-based Epidemiology (WBE), in which samples of municipal wastewater can be used as a diagnostic tool to explore a surprisingly broad range of community-wide health indices.
In research published in the peer-reviewed, high-impact journal Environment International, Rolf Halden and Sangeet Adhikari, describe how WBE can be used to help achieve a number of ambitious objectives outlined in the United Nations Sustainable Development Goals.
The study, the largest and most comprehensive assessment of wastewater infrastructure around the world to date, examines wastewater treatment facilities in 129 countries, serving over a third of the world's population. It is also the first study to propose and evaluate the feasibility of using WBE to measure progress toward achieving several UN sustainability objectives.
The WBE technique can be used to assess factors influencing community-wide health, from the consumption of local diets, alcohol, illicit drugs and tobacco to exposure to hazardous chemicals, pharmaceuticals, personal care products, viruses, and antibiotic-resistant microbes.
In addition to infectious disease monitoring, new disease biomarkers detectable in wastewater are being developed, enabling researchers to mine samples for evidence of afflictions including diabetes, heart disease and cancer. The study emphasizes the dire need for the expansion of wastewater services to large swaths of the globe where such resources are still lacking.
As recently as 2019, the use of wastewater monitoring to assess and optimize global health was a utopian dream, envisioned and pursued by few, as detailed in Halden's 2020 book, Environment. The COVID-19 pandemic, however, changed all of this, with the method put to immediate, practical use for tracking the devastating course of SARS CoV-2.
"Whereas most of these efforts today are still focused on containing the pandemic locally, it is time to take stock of what else can be accomplished using WBE to advance the human condition and sustainability globally," Halden says. "The first inventory of global wastewater infrastructure presented in our paper represents an initial and important step toward creating a healthier and more equitable future for human populations around the world."
Professor Halden is the director of the Biodesign Center for Environmental Engineering at Arizona State University, where he works with Sangeet Adhikari, who wrote the study as part of his recently completed doctoral thesis. Halden is also professor in ASU's School of Sustainable Engineering and the Built Environment, a member of the university's Global Futures Laboratory and professor in the School of Life Sciences.
A drop of water, a wealth of data
The effluent from human waste may seem far removed from a sterile clinical laboratory where diagnostic tests are performed. Yet both diagnostic approaches rely on the rich storehouse of information contained in bodily fluids and excretions.
Today, more than 55 countries are actively using WBE to evaluate community health. The method provides a comprehensive, inexpensive and rapid means of monitoring population-wide health. The initial burst in activity, due to the SARS CoV-2 crisis, enabled public health officials to evaluate local, regional and national disease trends even as pandemic surges posed severe challenges to conventional diagnostic testing.
A further benefit of WBE is that it can deliver population-level data reflecting the burden of undiagnosed COVID-19 cases, including asymptomatic infections that are unlikely to be detected through standard clinical surveillance. Such information is particularly valuable for epidemiologists hoping to refine estimates of case-fatality rates. It has been successfully applied by national and state governments, nongovernmental organizations, universities, and commercial ventures.
Monitoring health and sustainability
Halden and his ASU colleagues had long recognized the power of WBE to provide vital clues about the prevalence and transmission rates of pathogens and the novel coronavirus quickly turned into a showcase on how to apply wastewater monitoring to inform public health decision-making in real time. After creating the world's first wastewater-informed, open-access electronic dashboards for opioids in 2018/19 and for COVID-19 in 2020, in collaboration with the City of Tempe, AZ, the current study seeks to radically expand the scope of wastewater monitoring to benefit human populations around the world and particularly in developing countries.
By unanimous decision, 17 specific goals were announced by the UN to meet social, economic, and environmental development milestones. The UN agenda represents the determination of member countries to address global challenges posed by climate change, rapid urbanization, and other factors. The new study demonstrates that WBE could be used to effectively track the progress made toward achieving over half of these goals, set for 2030.
These include:
A range of health outcomes could also be dramatically improved simply through expansion of wastewater treatment technologies to the areas of greatest global need.
Earth inventory
The researchers began by conducting an in-depth literature survey of existing sewerage infrastructure, population demographics of the regions served and a range of health-related biomarkers available in wastewater that could be informative for furthering the UN goals.
The study identified some 109,000 municipal wastewater treatment plants in 129 countries, serving 2.7 billion people worldwide. This is equivalent to around 35% of the global population. Although some 80% of the population is served by municipal waste treatment systems in high-income countries, around 60 countries were identified in which less than 40% of the population is served. The grave disparities between rich and poor nations in terms of these facilities is partially responsible for their divergent health statistics.
Indeed, the study notes that areas lacking centralized sewerage infrastructure, particularly in low-income countries, are at a double disadvantage. Without such facilities, community hygiene is compromised; and affected populations are further deprived of the benefits of ongoing health monitoring provided by WBE. This fact is reflected in the observed data that showed a reduction in disease burden associated with centralized wastewater infrastructure.
Multi-purpose diagnostics
Providing access to sanitation infrastructure helps limit fecal contamination and the spread of waterborne diseases. Extending sewerage collection and treatment to areas lacking in this technology could provide a cost-effective strategy for health assessment through WBE under conditions where traditional healthcare is financially out of reach for most local people.
In addition to the detection of infectious disease, WBE can also assist in the management of chemical risks to the population, including microplastics, endocrine disrupting agents and a broad range of contaminants. The study also identifies 25 different classes of biomarkers that can provide valuable health statistics on community levels of hunger, stress, cardiovascular disease, pulmonary afflictions, and cancer.
The enhanced power of WBE for comprehensive health monitoring has significantly strengthened the case for extending sanitation infrastructure across the globe to safeguard human health as well as critical ecosystems. The new study also demonstrates the usefulness of the technique for helping society meet many of the United Nation's goals toward a healthier and more sustainable world.
Ultra-processed Foods In Diets Are Damaging Human And Planetary Health
A global diet that increasingly includes ultra-processed foods is having a negative impact on the diversity of plant species available for human consumption while also damaging human and planetary health, according to a commentary published in the journal BMJ Global Health.
Experts are warning that an increasingly unhealthy diet is not only bad for human health directly but is causing environmental damage to the planet.
Ultra-processed foods such as sweetened or salty snacks, soft drinks, instant noodles, reconstituted meat products, pre-prepared pizza and pasta dishes, biscuits and confectionery, are made by assembling food substances, mostly commodity ingredients, and 'cosmetic' additives (notably flavors, colors and emulsifiers) through a series of industrial processes.
These products are the basis of a 'globalized diet' and are becoming dominant in the global food supply, with sales and consumption growing in all regions and almost all countries. Currently, their consumption is growing fastest in upper-middle-income and lower-middle income countries.
Consequently, dietary patterns worldwide are becoming increasingly more processed
and less diverse, having an impact on agrobiodiversity – the variety and variability of animals, plants and microorganisms used directly or indirectly for food and agriculture.
Nutrition experts from Brazil, the US and Australia have written a commentary after investigating the issue.
They said that the bad effects of ultra-processed foods on human health were well documented, but there was still low awareness of their damaging impact on planetary health, and ultra-processed foods were missing from international development agendas.
They warned that global agrobiodiversity was declining, especially the genetic diversity of plants used for human consumption.
More than 7,000 edible plant species are used for human food, but fewer than 200 species had significant production in 2014, and just nine crops accounted for more than 66% by weight of all crop production.
As much as 90% of humanity's energy intake comes from just 15 crop plants, and more than four billion people rely on just three of them – rice, wheat and maize.
The authors warned that such a decline in biological diversity in food systems was disrupting and damaging biospheric processes and ecosystems that supported reliable and sustainable food production, reduced diet diversity and created a barrier to healthy, resilient and sustainable food systems.
They pointed to an ongoing study of 7,020 ultra-processed foods sold in the main Brazilian supermarket chains which had found that their five main ingredients included food substances derived from sugar cane (52.4%), milk (29.2%), wheat (27.7%), corn (10.7%) and soy (8.3%).
As a result, peoples' diets were less diverse, with ultra-processed foods replacing the variety of wholefoods necessary for a balanced and healthy diet.
Production of ultra-processed foods involved greater use of ingredients extracted from a handful of high-yielding plant species (such as maize, wheat, soy and oil seed crops) which meant that animal-sourced ingredients used in many ultra-processed foods were often derived from confined animals fed on the same crops.
Another issue of concern was that ultra-processed food production used large quantities of land, water, energy, herbicides and fertilizers, causing environmental degradation from greenhouse gas emissions and accumulation of packaging waste.
The authors concluded: "The very rapid rise of ultra-processed foods in human diets will continue to place pressure on the diversity of plant species available for human consumption.
"Future global food systems fora, biodiversity conventions and climate change conferences need to highlight the destruction of agrobiodiversity caused by ultra-processed foods, and to agree on policies and actions designed to slow and reverse this disaster.
"Relevant policy makers at all levels, researchers, professional and civil society organizations, and citizen action groups, need to be part of this process."
Source:
Journal reference:
Leite, F.H.M., et al. (2022) Ultra-processed foods should be central to global food systems dialogue and action on biodiversity. BMJ Global Health. Doi.Org/10.1136/bmjgh-2021-008269.
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