More than half of the world’s people do not have clean water at home

In 2021, the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) estimated that 2 billion people Access to clean water is lacking worldwide.

Roughly a quarter of the world’s population might seem bad enough. But on Thursday New research published in science The report that 2 billion was a huge underestimate. New analysis reveals that 4.4 billion people – more than half of the world’s population – do not have safe drinking water in low- and middle-income countries. Not that billions more have lost access to water. Rather, how researchers measure access has become much more precise, and those new measurements have shown that the problem is much worse than previously thought.

If you always have clean running water at home, it’s easy to forget that potable tap water isn’t provided for much of the planet.

In developed countries like the United States with sanitation systems, water is siphoned from a lake, river, or underground reservoir and passed through a treatment plant to filter out dirt, bacteria, and harmful chemicals. From there, it’s stored in something like a water tower and piped into homes. If everything is in order then the water is safe to drink.

However, this process is not 100 percent accurate. leaky pipeAging infrastructure, and chemical pollution limit access to safe water even in rich countries. While this is a logistical hurdle for countries where the vast majority of water is clean, cheap and abundant, the burden of providing safe drinking water to everyone in low- and middle-income countries is much more challenging, especially in rural areas, where there is limited sanitation infrastructure, conflict. , and inadequate funding can impede access to water.

Adequate access to clean, reliable, affordable drinking water is a human right, however, and The United Nations urged Governments funnel resources into building and maintaining water infrastructure. (One of the United Nations Sustainable Development Goals (Having clean water for every community—a distant goal.) Better funding is essential, but unless money is strategically directed to the right places and programs, throwing cash at the problem won’t necessarily solve it. That’s where new data comes in.

Esther GreenwoodDoctoral candidate at the Federal Institute of Technology Zurich and Ewag, an aquatic research institute in SwitzerlandA huge gap in information about drinking water services has been observed for more than half of the world’s population Filling this gap, Greenwood et al Principal investigator Tim Julian Aim to highlight areas where investment in drinking water testing is most needed.

“The fact that so many people around the world do not have reasonable access to safe drinking water should give us pause for thought,” the Ewag director Martin Ackerman Said “it can be avoided.”

More people lack access to safe drinking water than was thought — far more

Finding out how many people have access to safe water is no small feat, especially in rural areas where this data is most important. Historically, UNICEF has relied Household surveySending groups of people to personally interview a sample of homes in a given country. they asked questions like, “Could you please give me a glass of water that your family members usually drink?” and “Where was this water collected from?” — all of which provides a decent snapshot of a household’s current water situation.

But these surveys are labor-intensive and expensive, so data are collected only once every five to 10 years. Anything that affects water use on a smaller timescale, from animal husbandry from Seasonal change of rainfallShall not be taken prisoner. And until recently, surveys Didn’t ask about water quality After all, Greenwood added. For most regions, only one survey’s worth of data on drinking water contamination so far exists, making it difficult to assess trends over time.

Greenwood’s team included 39 different sources of geospatial data collected on the ground and via satellite between 2016 and 2020, in addition to survey data from more than 64,000 households in 27 countries. They use all this information to train machine learning models to make predictions Whether water fills a certain place Four security criteria From the WHO/UNICEF Joint Monitoring Program (JMP), which collects data on water supply, sanitation and hygiene: improved (eg, from a source that may be safe, such as a pipe, rather than an unprotected well), and whether it is available when needed was, accessible without traffic and free from faecal pollution.

In the past, water quality has been measured through survey results across a country’s entire population. Greenwood said JMP typically tries to average survey responses related to all of its water safety criteria, then highlight the lowest value. Say a country survey shows that 80 percent of people get water from an improved source, 50 percent have water at home, 40 percent have access to unbroken water, and 30 percent have clean, uncontaminated water — the JMP would report that 30 percent of people are safe. There is drinking water.

It washes out many nuances of people’s personal experience. If you have access to clean water, you have to go to a kiosk three miles away to get it? Or have access to consistent water at home, but it Piped into tanks via weekly truck deliveries (an “untreated” water source)?

To solve this problem, Greenwood’s team instead calculated the data at the household level and divided the land into smaller areas than in fully-developed countries to create a more accurate map of safe drinking water use. They found that two-thirds of people living in low- and middle-income countries did not have household access to safe drinking water in 2020.

How to purify water

For about half of the population studied, faecal contamination, or high levels of E. Coli was the biggest problem. When humans or animals defecate near water sources, or sewage is not effectively contained, E. Coli can be seen downstream of drinking water. Drinking contaminated water in this way causes diarrheal disease – an annoyance for adults but a killer for the young. More than 1,000 children die from this disease every dayPrimarily in South Asia and Sub-Saharan Africa.

Although E. While the technology needed to measure coli levels is widely available, actually collecting and testing drinking water samples is expensive, especially in remote rural areas. As a result, Greenwood says, “we still lack national data on drinking water contamination for nearly half of the world’s population.” Other chemicals eg Arsenic And pesticides They can also cause health problems when they enter drinking water, but data on these contaminants e. coli was even more limited—too limited for Greenwood’s team to include in their training data.

Greenwood’s team found that environmental factors, such as tree density and how much rainfall changes with season, are another major predictor of drinking water quality. This aligns with what researchers already knew—water quality is shaped in part by weather.

For example, after a big rain storm, it can collect bacteria, dirt and pollutants on its way back to rivers and lakes. Heat waves Also associated with spikes in water pollution, especially in low-income areas. As the world continues to warm, this will become an increasingly pressing concern – low-income countries currently face water insecurity. Also the most dangerous Impact of climate change.

Landscape and urban development also come into play. Sometimes, water is scarce because people built a city in a dry place, or that city overstretched its water supply. It was Cape Town in South Africa Almost forced to stop its water supply After a long drought in 2018, and a combination of limiting water supply and reducing demand, a major crisis was narrowly averted.

But often the problem is less how much water there is than its quality and its availability at home. Often wastewater treatment plants are poorly managedor Insufficient water pressure Piped water prevents the service from running consistently. For example, Mexico City may run out of water in the not-too-distant future due to a combination of climate change and human mismanagement. If city pipes run dry, alternative sources of water such as bottled water or the kiosk Usually found, but this can Cost up to 52 times.

Tackling huge policy issues like water insecurity requires a lot of data. Greenwood’s team began filling in some of the gaps left open by the JMP, but he said the kind of data they needed — frequent, hyperlocal measurements of water use over time — didn’t yet exist. These longitudinal data will be particularly important for understanding how climate change is affecting drinking water services. Because climate and weather fluctuate faster than a once-in-a-decade survey can capture, surveys alone won’t cut it.

Household data also does not necessarily reflect one’s daily water use. Also people drink water and go to the bathroom at work, school and other public facilities – and there are still huge information gaps Public water use. This survey did not address either Affordability of drinking wateror inconsistent The burden of water insecurity falls on women Often assigned the task of fetching water when not available at home.

While the kind of geospatial data Greenwood’s team used can’t necessarily answer those questions, it can help point resources in the right direction. Areas with particularly high levels of faecal pollution, or particularly densely populated areas with limited water sources, may be identified for government priority.

Greenwood hopes that by demonstrating the large impact accounting for geospatial data has had on water security estimates, his team can mobilize policymakers “towards improving global water quality monitoring, particularly in regions where there are current data gaps.”

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