New research reveals what’s really hiding in bottled water

Scientists estimate that bottled water drinkers swallow up to 90,000 more microplastic particles per year than those who stick to tap water.

Source:Concordia University

Summary:A chance encounter with plastic waste on a tropical beach sparked a deep investigation into what those fragments mean for human health. The research reveals that bottled water isn’t as pure as it seems—each sip may contain invisible microplastics that can slip through the body’s defenses and lodge in vital organs. These tiny pollutants are linked to inflammation, hormonal disruption, and even neurological damage, yet remain dangerously understudied.Share:

    

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What’s Really Hiding in Bottled Water
Recent research has revealed that people may be unknowingly ingesting tens of thousands of microplastic particles every year. On average, individuals consume between 39,000 and 52,000 particles annually, with bottled water drinkers taking in an additional 90,000 microplastic fragments compared to those who drink tap water. Credit: Shutterstock

Thailand’s Phi Phi Islands are known for their crystal-clear waters and white sand, not for launching advanced scientific research. Yet for one environmental scientist, the contrast between natural beauty and pollution sparked a major career shift from business to environmental science.

“I was standing there looking out at this gorgeous view of the Andaman Sea, and then I looked down and beneath my feet were all these pieces of plastic, most of them water bottles,” she says.

“I’ve always had a passion for waste reduction, but I realized that this was a problem with consumption.”

Armed with years of experience as co-founder of ERA Environmental Management Solutions, a company specializing in environmental, health and safety software, she returned to Concordia University to pursue a PhD on plastic waste. Her recent paper in the Journal of Hazardous Materials explores how single-use plastic water bottles pose potential health risks that remain largely overlooked in scientific research.

Hidden Hazards of Bottled Water

In an extensive review of more than 140 studies, the research reveals that people consume between 39,000 and 52,000 microplastic particles every year, and those who drink bottled water take in roughly 90,000 more than tap water users.

These microplastics are tiny fragments, often invisible to the eye. A typical particle measures between one micron (a thousandth of a millimeter) and five millimeters, while nanoplastics are even smaller. The contamination begins during manufacturing, transportation, and storage, when low-quality plastics release microscopic fragments — especially when exposed to sunlight and fluctuating temperatures. Unlike microplastics from food sources, those in bottled water are ingested directly.

Inside the Human Body

Once consumed, these particles can travel throughout the body. Studies indicate that microplastics can cross biological barriers, enter the bloodstream, and accumulate in organs. This may cause chronic inflammation, oxidative stress, hormonal disruption, reproductive impairment, neurological issues, and even some cancers. However, the long-term impact remains uncertain due to limited standardized testing and measurement techniques.

The researcher highlights that current detection tools vary in precision and capability. Some methods can spot smaller particles but cannot identify their composition, while others analyze chemical makeup but miss the tiniest plastics. The most advanced systems are both expensive and difficult to access, hindering consistent global study.

Rethinking Plastic Use Through Education

Despite growing environmental laws aimed at reducing plastic pollution, most regulations target items like shopping bags, straws, and packaging. Single-use water bottles often escape similar scrutiny.

“Education is the most important action we can take,” she says. “Drinking water from plastic bottles is fine in an emergency but it is not something that should be used in daily life. People need to understand that the issue is not acute toxicity — it is chronic toxicity.”

Chunjiang An, associate professor, and Zhi Chen, professor, in the Department of Building, Civil and Environmental Engineering at the Gina Cody School of Engineering and Computer Science contributed to this paper.

This research was supported by the Natural Sciences and Engineering Research Council of Canada and Concordia University.

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https://www.sciencedaily.com/releases/2025/10/251006051131.htm?

EWG: Reducing multiple tap water contaminants may prevent over 50,000 cancer cases

Study shows health benefits of tackling arsenic, chromium-6 and other pollutants at once

WASHINGTON – Drinking water treatment that pursues a multi-contaminant approach, tackling several pollutants at once, could prevent more than 50,000 lifetime cancer cases in the U.S., finds a new peer-reviewed study by the Environmental Working Group.

The finding challenges the merits of regulating one tap water contaminant at a time, the long-standing practice of states and the federal government. 

In the paper, published in the journal Environmental Research, EWG scientists analyzed more than a decade of data from over 17,000 community water systems. They found that two cancer-causing chemicals – arsenic and hexavalent chromium, or chromium-6 – often appear together in systems and can be treated using the same technologies. 

If water systems with chromium-6 contamination also reduce arsenic levels to a range from 27% to 42%, it could avoid up to quadruple the number of cancer cases compared to just lowering chromium-6 levels alone, the study finds. 

Treatment of drinking water for one contaminant, such as nitrate, has advantages for public health. But tackling multiple contaminants at once increases the health benefits. And those benefits can expand along with the number of pollutants treated at the same time. 

 “Drinking water is contaminated mostly in mixtures, but our regulatory system still acts like they appear one at a time,” said Tasha Stoiber, Ph.D., a senior scientist at EWG and lead author of the study. “This research shows that treating multiple contaminants together could prevent tens of thousands of cancer cases.”

Chromium-6 and arsenic are commonly found in drinking water across the U.S. Chromium-6 has been found in drinking water served to 264 million Americans. 

“Addressing co-occurring contaminants is scientifically the most sound approach, as well as an efficient way to protect public health,” added Stoiber.

In California alone, nearly eight out of 10 preventable cancer cases are linked to arsenic exposure.

Arizona, California and Texas bear the highest burden of arsenic pollution and would gain the most from multi-contaminant water treatment efforts.

Health risks of water contaminants

Toxic chemicals like chromium-6, arsenic and nitrate pose the greatest risks to children, pregnant people and those living in smaller communities served by water systems relying on groundwater. Systems serving these populations often rely on only one water source and the smaller communities lack the resources to demand better treatment, despite facing the most serious health harms.

Chromium-6 

This cancer-causing chemical made infamous by the film “Erin Brockovich” is linked to serious health risks. Studies show even low levels in drinking water can increase the risk of stomach cancer, liver damage and reproductive harm. 

In 2008, the National Toxicology Program found much higher rates of stomach and intestinal tumors in lab animals exposed to chromium-6 in water. California researchers later confirmed a higher risk of stomach cancer in workers who had been exposed.

The Environmental Protection Agency does not limit the amount of chromium-6 in drinking water. It does regulate total chromium, which includes chromium-6 and the mostly harmless chromium-3. Total chromium is set at 100 parts per billion, or ppb, for drinking water.

Arsenic

Arsenic is found in drinking water in all 50 states. It occurs in natural deposits and as a result of human activities such as mining and pesticide use. Long-term exposure is linked to serious health issues, including bladder, lung and skin cancers, as well as cardiovascular and developmental harm.

The legal federal limit for arsenic in drinking water is 10 ppb, set in 2001 based on outdated cost estimates for treatment, not on what’s safest for health. California’s public health goal is just 0.004 ppb, the level scientists say would pose no significant cancer risk over a lifetime.

Arsenic can also contaminate certain foods, especially rice and rice-based products, making clean water standards all the more important for reducing overall exposure.

Nitrate 

Nitrate is one of the most common drinking water contaminants, especially downstream from agricultural areas where it enters water supplies through fertilizer and manure runoff. It’s also found in private wells, often near farms or septic systems.

Exposure to nitrate in drinking water is linked to serious health risks, including colorectal and ovarian cancer, very preterm birth, low birth weight, and neural tube defects. 

The EPA set the nitrate limit at 10 parts per million in 1992 to prevent “blue baby syndrome.” But it hasn’t updated the standard in over 30 years. New research shows cancer and birth-related harms can occur at levels far below the legal limit. European studies have found increased cancer risks at nitrate levels more than 10 times lower than the EPA limit.

“Ensuring clean drinking water for all communities is about fairness and equity,” said Sydney Evans, MPH, EWG senior science analyst and a co-author of the new study. 

“Communities in the U.S. that rely on groundwater are often affected by these contaminants. New water treatment technologies offer a chance to improve water quality overall. This strengthens the case for action and investment.”

Call for smarter water rules

Federal regulations still evaluate the cost and benefit of water treatment on a one-contaminant basis, a model EWG’s report calls outdated and inefficient. 

Small and rural water systems often face the steepest per-person costs to implement new treatment technologies. But they’re among the most exposed to pollutants and associated risks.

These systems frequently lack the funding and technical support to upgrade aging infrastructure, leaving residents exposed to serious health threats. This level of vulnerability calls for new strategies for these communities – a  boost in funding coupled with more effective regulations.

For example, nitrate, often found alongside chromium-6 in drinking water, represents a major but overlooked opportunity for health protection.

“Nitrate pollution is a public health crisis, particularly in the Midwest but also across the country,” said Anne Schechinger, EWG’s Midwest director. “The federal nitrate limit was set decades ago to prevent infant deaths, but we now know see cancer and birth complications at levels of nitrate far below that outdated standard.

“Even lowering nitrate slightly could prevent hundreds of cancer cases and save tens of millions of dollars in health care costs, especially when paired with treatment for other contaminants, such as chromium-6 and arsenic,” she said. “There’s a real cost to inaction – our health and our wallets can’t afford to wait for better treatment.”

Proven technologies like ion exchange and reverse osmosis, already used today, can remove nitrate, chromium-6 and arsenic from drinking water at the same time. 

“This is about more than clean water – it’s about protecting health and advancing equity,” said David Andrews, Ph.D., acting chief science officer at EWG. “We have the engineering solutions to fix the broken drinking water system in the U.S., but we need state and federal policies to reflect the reality people face when they turn on the tap.”

Consumers concerned about chemicals in their tap water can install a water filter to help reduce their exposure to contaminants. The home filter system that’s most effective for removing chromium-6, arsenic and nitrate from water is reverse osmosis. Ion exchange technology is another option for reducing levels of these contaminants.

EWG’s water filter guide contains more information about available options. It is crucial to change water filters on time. Old filters aren’t safe, since they harbor bacteria and let contaminants through.

People can also search EWG’s national Tap Water Database to learn which contaminants are detected in their tap water.

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The Environmental Working Group is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action.

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https://www.ewg.org/news-insights/news-release/2025/07/ewg-reducing-multiple-tap-water-contaminants-may-prevent-over?

EWG Tap Water Database update shows hundreds of contaminants widespread in U.S. tap water

Search by postal code for water quality reports and filter recommendations

WASHINGTON – This year’s update to the Environmental Working Group’s Tap Water Database shows millions of Americans are drinking water tainted with harmful chemicals, heavy metals and radioactive substances. Many of these contaminants are at levels far above what scientists consider safe.

EWG’s latest analysis includes water quality data collected between 2021 and 2023 from nearly 50,000 water systems. It identified 324 contaminants in drinking water across the country, with detectable levels in almost all community water systems.

“This is a wake-up call,” said Tasha Stoiber, Ph.D., a senior scientist at EWG. “For over 30 years, EWG has been at the forefront of advocating for stronger drinking water protections. Outdated federal regulations continue to leave millions of people at risk of exposure to harmful substances.

“Our Tap Water Database is the only resource providing consumers in every state access to accurate information about water contaminants, health risks and steps to reduce exposure through filtration – information they need so they can take action,” she said.

The levels of contamination in many locations fall largely below the Environmental Protection Agency’s outdated legal limits. But they often far exceed EWG’s health-based standards, the sweeping analysis of nationwide water utility tests found.

The Tap Water Database empowers virtually everyone in all 50 states and the District of Columbia to check local water quality and take action to improve it, if necessary. By entering their ZIP code, users can easily find detailed information about the contaminants in their local water supply, including tips on choosing the right water filter to reduce exposure.

“Consumers shouldn’t need to worry if their water is safe to drink,” said Sydney Evans, a senior science analyst at EWG. “The burden also shouldn’t fall to individuals to filter out hazardous substances that shouldn’t be in water taps to begin with.”

The update highlights contaminants in U.S. drinking water, including the toxic “forever chemicals” known as PFAS, that are in the drinking water of over143 million people. Tap water throughout the U.S. can also contain volatile organic compounds, nitrate and arsenic, among many other contaminants. These pollutants, often linked to cancer, developmental issues and other health risks, are found in nearly all community water systems.

Harmful disinfection byproducts and radiological contaminants also persist in water supplies in many communities.

Hexavalent chromium, or chromium-6, is a carcinogen made infamous by the Erin Brockovich case in Hinkley, Calif., and it’s in the drinking water of over 250 million Americans. There is no federal limit for chromium-6, despite its widespread presence and link to cancer and organ damage.

EPA efforts to safeguard drinking water continue to lag

Despite mounting scientific evidence and public concern about U.S. drinking water quality, federal action remains slow. In 2024, the Biden EPA introduced its first drinking water standards in more than 20 years, setting health-protective maximum contaminant limits for six PFAS.

“For too long, outdated federal standards have failed to reflect the latest science on drinking water, leaving millions exposed to harmful chemicals,” said Melanie Benesh, vice president of government affairs at EWG. “While the new PFAS standards represent a historic step forward, they are only a fraction of what is needed to protect public health.”

The EPA standards are critical in reducing PFAS contamination in the nation’s water supply. But these vital new protections could be at risk if the Trump administration tries to roll them back, along with weakening other steps the Biden EPA took to tackle PFAS pollution.

“Safe drinking water shouldn’t be a political debate – it’s a fundamental right. A rollback of these hard-won protections would be a devastating setback. We must push for stronger, science-based regulations to ensure safe water for every American,” said Benesh.

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The Environmental Working Group is a nonprofit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through research, advocacy and unique education tools, EWG drives consumer choice and civic action. 

CLICK HERE FOR MORE INFORMATION

https://www.ewg.org/news-insights/news-release/2025/02/ewg-tap-water-database-update-shows-hundreds-contaminants?

Integrating water quality and water quantity to diagnose the health of water metabolism systems in multi-core multi-level urban agglomerations

Author links open overlay panelYing Yang a1

, Jing Wen a1

, Meirong Su b

, Qionghong Chen cShow moreAdd to MendeleyShareCite

https://doi.org/10.1016/j.watres.2025.123899Get rights and content

Highlights

  • •The MRIO table was compiled for a multi-core multi-level urban agglomeration.
  • •A diagnostic framework was established by coupling ENA and MRIO approaches.
  • •Water quantity-water quality linkage was considered in the diagnostic framework.
  • •The IWMN was less vigorous and less organized than the QWMN.
  • •The IWMN tended slightly towards mutualism but had more negative collaborations.

Abstract

Urban agglomerations (UAs) are compelled to scrutinize the health of their water systems as the frequency of water crises increases. An urban water system’s health is closely related to metabolism processes. To date, water systems in multi-core multi-level UAs have not been analyzed using water quantity and water quality because of methodological constraints. To address this research gap, we developed an integrated water quality–water quantity model for diagnosing water metabolism systems that could process nested multi-region input-output (MRIO) tables. We coupled the MRIO tables and established two networks, an integrated water quantity–quality metabolism network (IWMN) and a water quantity metabolism network (QWMN). We tested the two networks with data from the Guangdong-Hong Kong-Macao UA and assessed four aspects of the networks’ health, namely vigor, organization, resilience, and collaboration, using ecological network analysis. We discovered that IWMN exhibited lower vigor (internal circulation 10.4 %) and organization dominated by dependency (total contribution intensity σ = -23) compared to the QWMN. Polity-driven disparities shaped the robustness distribution, while a mutualism tendency coexisted with a complex exploitation relationship (52.4 %), particularly in the core large-sized city of Hong Kong, where 58 new competitive pairs emerged. Thus, we recommend prioritizing Guangdong-Hong Kong-Macao trade optimization for high-water-content products to enhance system health.

Graphical abstract

Image, graphical abstract

Introduction

The surface water deficit experienced in 482 of the world’s largest cities is projected to reach 6.75 million tons by 2050 because of an imbalance between the water supply and the demand (Flörke et al., 2018). This trend has prompted growing interest in resource allocation and environmental protection within urban agglomerations (UAs). UAs are composed of multiple geographically adjacent cities with diverse sizes and characteristics (Fang et al., 2015). Diverse UAs with multi-core structures (classified by comprehensive urban engine functions) and multi-level systems (quantified by social indicators) face challenges due to high heterogeneity in population size and spatial resource allocation (Han et al., 2019; Chirigati, 2022; Zhao et al., 2021). Water quantity and water quality are important attributes of water resources. Changes in the water quantity caused by a lack of rainfall or heavy rainfall events affect the water quality by concentrating pollutants or diluting. Conversely, degraded water quality diminishes the availability of water resources (Li et al., 2023) and has direct effects on urban aquatic ecosystems (Liu and Yang, 2012). Therefore, to optimize water management in multi-core multi-level UAs, we need to know more about the combined effects of water quality and water quantity on the water resources.

When optimizing water management in urban areas, the water metabolism mechanism of the system should be analyzed, and key issues should be identified (Cao et al., 2021; He et al., 2020b; Liu et al., 2022). The concept of water metabolism originates from urban metabolism (Wolman, 1965), which describes water cycle processes (e.g., water input, output, and storage) driven by social activities in different cities (Wang and Chen, 2010). This concept can effectively identify hidden risks resulting from the allocation of social resources—such as population, industry and environment within UAs, thus challenging the traditional multilevel paradigm of urban water management. In assessing the health of water systems based on water metabolism mechanisms, processes analogous to those in natural ecosystems, such as vigor and collaboration (Y.J. Yang et al., 2020; Zhu et al., 2020), sustained and stable organization, and adaptability to external pressures (Yan et al., 2014), are employed. However, to date, most research has primarily focused on the efficiency of consumptive activities (Nishimura et al., 2021; Qi et al., 2021; Xu et al., 2020), while ignoring the underlying water metabolism processes.

Network methods are effective for characterizing critical resource metabolism processes (Liang et al., 2020). Ecological Network Analysis (ENA) (Hannon B, 1973) quantifies metabolic features via resource fluxes (Fath, 2004; Ulanowicz et al., 2009), offering insights into system health. For example, resource footprint circulation rates reflect node vigor; balanced control-dependency relationships enhance organizational capacity; maintaining metabolic orderliness optimizes resilience thresholds; and niche complementarity indices help analyze co-evolutionary collaboration. There is concern about the approaches used to quantitatively assess the resource flows within a network. A bottom-up approach uses industrial processes to track water flows (Vanham and Bidoglio, 2013), but a top-down approach quantitatively assesses the resource flows within a network (Feng et al., 2011). For example, input-output analysis (IOA), an accepted method for quantifying water flows in a water metabolism system, is preferred over bottom-up approaches because it can link industrial economic data to water consumption using input-output tables and produce a high-resolution view of the networked water flow transactions, helping us to address issues caused within UAs by economic trade, such as water-related resource flows, ecosystem services, and health status (Hubacek and Feng, 2016). However, our ability to carry out a comprehensive and accurate assessment of water system health within UAs is hampered by a lack of high-resolution MRIO data for multi-core multi-level UAs, which has resulted from the poor alignment of statistical standards used for trade data across cities of different levels.

To date, there is little clarity about how the combination of water quantity and water quality influences the health of water metabolism systems in UAs. Cao et al. (2021) were the first to evaluate the health of water networks using an assessment model that focused on water quantity, but excluded water quality. Adequate water quantity and sufficient water quality are essential for the sustainable use of urban water resources (Cai et al., 2023). A water footprint, which incorporates both water quantity and water quality, can be used to assess water flows (Hoekstra and Mekonnen, 2012). Various water footprints have been defined, and the blue water footprint (BWF) and grey water footprint (GWF) have been used to quantify both water quantity and water quality (Chapagain and Hoekstra, 2011; Yu et al., 2022). In previous studies, researchers have focused on either water quantity or water quality when assessing the intensity of resource transfers (Cai et al., 2023; Zhao et al., 2016) and the factors that influenced them (Cai and Guo, 2023; Guan et al., 2014). Some researchers have also simulated and evaluated the performance of metabolism systems using either water quantity or water quality as the independent metabolism medium (He et al., 2020b, 2020a; Liu et al., 2022). The conventional separation of water quantity and quality in current research paradigms makes it difficult to reveal the cascading effects of their synergistic interactions on multiscale metabolism systems, which may lead to ecological cognitive bias in system health assessments. As synergistic variables within regional metabolism system, the mechanisms underlying the interactions between water quantity and water quality remain underexplored. It is imperative to conceptualize water quantity and quality as an integrated metabolism medium and develop a corresponding theoretical framework to elucidate how their synergistic metabolic processes influence system health.

The diagnoses of water metabolism system health at the UA scale are constrained by a) a lack of MRIO tables, which hinders the accurate assessment of water flow within UAs with multi-core and multi-level cities, and b) a limited understanding of how the health of metabolism systems is influenced when water quantity and water quality are combined into a single metabolism medium. To address these issues, we proposed a method for compiling MRIO tables for multi-core multi-level UAs that resolved the methodological limitations associated with assessments of water flow. We created two networks based on MRIO and ENA, one that integrated water quantity and water quality and another for water quantity only, and assessed four attributes of the health of the two networks, namely vigor, organization, resilience, and collaboration. We then tested the method with data from the Guangdong-Hong Kong-Macao Greater Bay Area UA (GBA).

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https://www.sciencedirect.com/science/article/abs/pii/S0043135425008073?via%3Dihub

Influence of particulate matter air quality on water quality of atmospheric water harvesting

Author links open overlay panelMatthew Russell ab

, Alex Webster c

, Carl Abadam bd

, Katelin Fisher b

, Stephanie Campbell bd

, Carmen Atchley bd

, Kana Radius bd

, Paris Eisenman bd

, Ashley Apodaca-Sparks bd

, Astrid Gonzaga bd

, Rui Liu e

, Patrick Hudson f

, Anjali Mulchandani abdShow moreAdd to MendeleyShareCite

https://doi.org/10.1016/j.watres.2025.124213Get rights and content

Under a Creative Commons license

Open access

Abstract

Atmospheric water harvesting (AWH) is a decentralized water technology that dehumidifies air to provide water. When atmospheric water is condensed, other atmospheric particles and gases can enter the liquid water. For AWH to serve as drinking water, it is necessary to understand how these air constituents interact with water as it condenses and the resulting water quality. The objectives of this research were to determine: i) the variation of measured air and water quality contaminants at two sites, and ii) the extent of interaction between particulate matter concentration in the air and the water quality of atmospherically harvested water. This study performed AWH using compressor dehumidifiers at industrial and urban ambient air quality monitoring sites in Albuquerque, New Mexico, USA. Air contamination was greater at the industrial site compared to the urban site (range PM2.5 urban 1.3 – 33.4 μg/m3, industrial 1.8 – 127.5 μg/m3; range PM10 urban 3.7 – 99.2 μg/m3, industrial 4.4 – 1525 μg/m3). Water trace metals concentrations and turbidity were also greater at the industrial site. Aluminum concentrations ranged 22.9 – 600 μg/L (urban) and 22.1 – 1560 μg/L (industrial); Iron ranged 0.5 – 363 μg/L (urban), 3.4 – 828 μg/L (industrial); Manganese ranged 0.7 – 23.7 μg/L (urban), 1.3 – 69.2 μg/L (industrial); and turbidity ranged 0.3 – 28 NTU (urban), 0.5 – 52 NTU (industrial). Water quality exceeded U.S. EPA regulations for aluminum (39 % of samples at urban site, and 90 % of samples at industrial site > 200 µg/L) and turbidity (96 % at urban site, 100 % at industrial site > 0.3 NTU). A linear mixed-effects statistical model showed water quality was a function of air quality, but for only some parameters. At the industrial site, there was a strong positive relationship between PM2.5 and some metals (aluminum, calcium, iron [p<0.05]), and marginal significance with other metals (potassium, zinc [p<0.1]). At the urban site, there was only a strong positive relationship between PM2.5 and calcium. Large variations in PM concentrations and site differences in their characteristics could play an important role in how much of metals in the air enters atmospherically harvested water. Findings from this study can guide research on understanding if air quality can be used to predict AWH water quality, provide insight to further understand the mechanisms of interaction between gas-phase water and particles as they move from the air to condensed water, and drive treatment decisions to meet water quality goals.

Graphical abstract

Image, graphical abstract

Keywords

Dehumidification

Condensation

Aerosols

Water vapor

Pollutants

1. Introduction

Global warming and the increased variability and intensity of natural disasters (e.g., floods, droughts, wildfire) are a continuing concern to water supplies. Any of these natural disasters can impact municipal water supplies and limit access for weeks to months. The atmosphere is an alternative freshwater reservoir that contains 12,900 km3 of water (Shiklomanov, 1991), is universally accessible, and can serve as a water source when other supplies are inaccessible. Atmospheric water harvesting (AWH) can condense this available water vapor to provide access to water for communities in need during emergencies (Gayoso et al., 2024; Mulchandani and Westerhoff, 2020).

There are few studies on AWH water quality, and the relationship between air quality and water quality has only been minimally investigated for both condensation and sorption-based systems (Mulchandani et al., 2022; Zeng et al., 2024). These AWH water quality studies are often performed at a single site for around 12 months (Mulchandani et al. 2022), while few have studied AWH across multiple sites and months (Xia et al., 2015). These studies find turbidity, aluminum, iron, and manganese concentrations above United States Environmental Protection Agency (U.S. EPA) and World Health Organization (WHO) drinking water regulations in untreated AWH water, and aluminum and iron above regulatory values in treated AWH water (Zeng et al., 2024). As more studies are performed, it is apparent that there may be large variability in concentrations of metal and organic contaminants over space and time. The concentration of these contaminants may be impacted by variability in air quality, but this influence is not well studied. Xia et al. (2015) studied the relationship between particulate matter (PM) and ion contaminants in condensation-based atmospherically harvested water and found high concentrations of Cl–, SO42-, NH4+ and Ca2+ in industrial areas associated with soil dust and exhaust. This study was performed in a temperate climate (relative humidity ranged 60–80 %), and it is unknown whether these results are transferable or universal for all climate zones and pollution sources, specifically those experienced in more arid regions. For AWH to be considered a viable drinking water source in multiple regions, more data is needed to understand the extent and nature of air quality influence on AWH water quality. Spatial and temporal analysis across environments (e.g., arid with heavy agricultural and urban emissions sources, vs humid with heavy industrial emissions) is needed to determine the full range of potential water quality.

Air quality is influenced by natural and anthropogenic emissions of trace gases and aerosols as well as meteorological factors such as temperature, wind speed, and humidity. As such, air quality can vary across a geographic region and changes throughout the day (Hosein et al., 1977). The U.S. EPA classifies and measures outdoor air pollution by 6 criteria pollutants: ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), lead (Pb) and particulate matter (PM) pollution (US EPA, 2015a). Of these pollutants, PM may be most likely to influence chemical makeup of AWH water quality due to the interaction between PM and gas phase water in the atmosphere.

Fig. S1 shows how PM and gas-phase water interact in the atmosphere. PM is formed through nucleation, accumulation and coarse modes. In nucleation mode, particles are freshly formed through combustion or atmospheric reactions from emissions sources such as traffic, industry and burning (EPA, 2023). These particles grow through coagulation with water vapor and other constituents to get to accumulation mode. As small particles stick together, the total particle number decreases, and the mass and surface area of each coagulated particle increase. Lastly, coarse mode generally consists of mechanically separated particles that may be resuspended from surfaces. PM is classified as fine (<2.5 m) and coarse (<10 m) and is often made up of clusters of different constituents depending on the emissions that influence the air quality (EPA, 2019). PM2.5 typically contains crustal material comprising of metal compounds (Al, Cu, Fe, K, Mn, etc.), soil, small liquids, elemental carbon, volatile organic compounds and various ions (SO42- and NO3–) (Chemical Elements, Minerals, Rocks, 2024; EPA, 2023; Hasheminassab et al., 2014). PM10 is typically produced by surface abrasion, sea spray, biological materials, and road, crop and livestock dust (EPA, 2023). Water vapor in the air continue to interact with particulates, which may partition with water vapor into condensed AWH waters. We theorize that when this water vapor condenses within an AWH system, particles of all sizes from various sources (e.g., traffic, industry and burning) containing constituents such as metals, carbon and gases will be collected in the harvested water and impact water quality.

Currently, there is a knowledge gap regarding the relationship between PM concentrations and characteristics, and subsequent water quality of AWH, particularly as it varies by space and time to determine site specific impacts. These relationships may vary as a function of location, climate, and air quality. Closing this gap can provide key insight on the level and type of treatment required to make AWH a viable drinking water source. If there is a significant relationship between air quality measured as PM and water quality, air could be pre-filtered to remove PM before harvesting. Alternatively, post-harvesting water treatment may be applied to remove both particles and dissolved constituents.

The objectives of this research were to determine: i) the variation of measured air and water quality contaminants by site, and ii) the extent of interaction between particulate matter concentration in the air and the water quality of atmospherically harvested water. Condensation-based AWH devices were operated in a semi-arid high-desert metropolitan city. AWH devices were co-located with air quality monitoring instrumentation to directly compare air quality with AWH water quality. The air was not pre-filtered, and AWH water samples were not filtered or treated in order to gain a full understanding of the impact of PM on water quality. We hypothesized that air pollution and AWH water pollution would be greater at the industrial site compared to the urban site. Secondly, we hypothesized that there would be a positive linear relationship between both PM10 and PM2.5 and total organic carbon and metal concentrations, the nature of which may be specific to each site. Findings from this study can guide research on understanding if PM can be used to predict AWH water quality, provide insight to further understand the mechanisms of interaction between gas-phase water and particles as they move from the air to condensed water, and drive treatment decisions to meet water quality goals.

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https://www.sciencedirect.com/science/article/pii/S0043135425011200?via%3Dihub

Assessment of water quality and health hazards using water quality index and human health risk evaluation in district Talagang Pakistan

Scientific Reports volume 15, Article number: 5191 (2025) Cite this article

Abstract

This work was carried out for the determination of the water quality in the Talagang District of Pakistan, as water is essential for agriculture and drinking uses. This study aims to assess the water quality for irrigation, drinking, and health risks using the Water Quality Index (WQI) and Human Health Risk Assessment (HHRA) tools to identify regions with contaminated water, and to evaluate the associated risks. A total of 98 water samples were taken at various points from diverse sources such as hand pumps, streams, springs, dug wells, and tube wells for physio-chemical assessment. In the current study, the effectiveness of the irrigation water quality index (IWQI), human health risk assessment (HHRA), and water quality index (WQI) tools have been assessed. The characteristics of subterranean water are influenced by evaporation, ion exchange, rock-water interaction, and parent-rock weathering, as shown by the Piper and Gibbs diagram. According to the WQI results, the water quality is 20. 89% and 27.46% of the sample sites are moderate and poor, making them unfit for human intake. Based on HHRA, compared to adult males and females in the study area, children are deemed to be at a higher risk. A larger number of the sample localities are appropriate for irrigation purposes. The study assists in identifying contaminated regions and in monitoring newly implemented remediation actions to manage the source of contaminants in the study area.

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Hydro-chemical profiling and contaminant source identification in agricultural canals using data driven clustering approaches

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New approach to predict wastewater quality for irrigation utilizing integrated indexical approaches and hyperspectral reflectance measurements supported with multivariate analysis

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Evaluation of water quality index and geochemical characteristics of surfacewater from Tawang India

Article Open access09 July 2022

Introduction

Surface and subterranean water are essential sources of drinking, farming, industrial, and domestic uses worldwide and also have a substantial effect on shaping the quality of lives and sustainability of societies1. Due to rapid growth and population increase, natural and human actions such as industry, urbanization, mining, and agriculture have resulted in water depletion and impairment issues2,3. Water quality degradation and depletion have emerged as significant global challenges, directly impacting public health, agriculture, and the environment4,5. The poor quality of water poses both direct and indirect health risks to the communities that rely on it, often leading to substantial public health issues and increased costs for water treatment and rehabilitation6. Direct health risks are associated with the consumption of contaminated water, such as heavy metal contamination, which can cause serious illnesses7,8. Indirect health risks occur when contaminated water is used for irrigation, affecting agricultural crops, horticulture, and aquaculture, leading to bioaccumulation of toxins in the food chain9.Heavy metals including Zn, Cu, and Mn are naturally occurring in water in trace amounts and are significantly essential for human metabolism and the growth of living things10. However, excessive amounts of these metals pose chronic and acute health issues. Other heavy metals including Pb, Cd, As, Cr, and Ni are severely toxic although in very low concentrations11. For example, the higher concentration of Pb is known to harm the development of the brain in children. Exposure to elevated concentrations of Cd causes chronic and acute diseases such as skeletal and kidney damage. The As causes many health problems in humans such as skin lesions, and cancer of the liver, brain, stomach, and kidney12,13. Higher intakes of Cr and Ni have been linked with liver, kidney, and heart problems14. The WQI is a handy means for evaluating the quality of water that is appropriate for residential practice. The weighted arithmetic and integrated WQI are extensively used in India for assessing surface and subterranean water because it yield results with greater accuracy1516. investigatedthe chemistry and quality index of groundwater in northwest China and noticed that 11.43% of sample locations had poor water quality, and 17.14% had very poor water quality. Similarly17, used weighted overlay analysis to assess groundwater quality for drinking and irrigation purposes in Bangladesh, revealing that 90% of water from deep wells and 57.6% from shallow wells were suitable for human consumption, according to the Drinking Water Quality Index (DWQI).

Several recent studies have employed various techniques to assess water quality, including the use of WQI, which integrates multiple physicochemical variables into a single dimensionless value representing overall water quality18,19,20,21,22. The WQI is an assessment model that can be used for integrating a variety of physicochemical variables into a dimensionless value that may depict the overall quality of the water18,20. n Pakistan, water quality contamination has been reported in several regions, affecting both surface and groundwater resources11. Given the importance of water for human health, agriculture, and overall well-being, it is crucial to evaluate the water quality in various regions. The primary objective of this study is to assess the surface and subsurface water quality for irrigation, drinking, and health risks in Talagang District, Pakistan, using the Water Quality Index (WQI) and Human Health Risk Assessment (HHRA) tools. This research aims to evaluate the hydro-chemical parameters of groundwater in the study area for both irrigation and drinking purposes, and to assess the associated health risks using the WQI and HHRA models. The findings will contribute to identifying areas where water quality poses health risks and help in formulating strategies for water management and remediation.

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https://www.nature.com/articles/s41598-025-89932-y?

Unsafe drinking water and human health: A global umbrella review of disease outcomes, intervention effectiveness, and policy implications

Author links open overlay panelShen Li (李燊) 16

, Yuhao Wei (韦宇豪) 16

, Jingxuan Zhou (周靖宣) 26

, Yifan Li (李逸帆) 16

, Lichun Qiao (乔利春) 3

, Diqing You (犹迪庆) 4

, Yuting Jiang (江雨婷) 1

, Zedong Jiang (江泽东) 1

, Xiawei Wei (魏霞蔚) 15

, Xuelei Ma (马学磊) 17Show moreAdd to MendeleyShareCite

https://doi.org/10.1016/j.xcrm.2026.102588Get rights and content

Under a Creative Commons license

Open access

Highlights

  • •Unsafe water is linked to cancer, infection, cardiovascular, and maternal-neonatal risks
  • •Water filtration and defluoridation effectively reduce disease risks
  • •Risk attribution robustness varies; intervention benefits are robust
  • •Policy should prioritize proven solutions over precise risk estimates

Summary

Access to safe drinking water is a fundamental determinant of global health. In this umbrella review, we synthesized evidence from 25 systematic reviews and meta-analyses, covering 158 outcomes, to assess health risks and intervention effectiveness (PROSPERO: CRD420251001778). Employing a rigorous methodological framework including A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2); Evidence Classification; the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE); and simplified evidence-to-decision criteria, we identified significant associations between unsafe drinking water and various health conditions, including infectious diseases, cancers, cardiovascular diseases, and adverse maternal-child health outcomes. Importantly, while the certainty of evidence for precise risk attribution remains limited, evidence supporting effective interventions is robust. Point-of-use (POU) filtration reduces childhood diarrhea by 52% (relative risk [RR] = 0.48; moderate-certainty evidence), and defluoridation effectively prevents fluorosis. Overall, these findings support a shift in policy focus: despite uncertainties in exact risk quantification, public health strategies should prioritize immediate implementation of proven interventions to safeguard vulnerable populations.

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https://www.sciencedirect.com/science/article/pii/S2666379126000054?

Health risk assessment of groundwater use for drinking in West Nile Delta, Egypt

Scientific Reports volume 15, Article number: 7414 (2025) Cite this article

Abstract

Human health is at risk from drinking water contamination, which causes a number of health problems in many parts of the world. The geochemistry of groundwater, its quality, the origins of groundwater pollution, and the associated health risks have all been the subject of substantial research in recent decades. In this study, groundwater in the west Rosetta Nile branch of the Nile Delta Aquifer is examined for drinking potential. Numerous water quality indices were applied, such as water quality index (WQI), synthetic pollution index (SPI) models, and health risk assessment (HRA) method. The limits of the measured parameters are used to test its drinking validity on the basis of WHO recommendations. TDS in the southern regions is within the desirable to allowable limits with percent 25.3% and 29.33%, respectively. Nearly all the study area has desirable value for HCO3, Al and Ba. Ca and Mg have desirable values in the center and south portion of the investigated area, whereas in the north are unsuitable. Na, Cl and SO4 fall within the desired level in the regions of the south but become unsuitable towards the north. Mn and NO3 are inappropriate except in the northwestern part. Fe is within suitable range in the southwestern and northwestern regions. Pb, Zn, Cu, and Cd were undetected in the collected samples. Regarding to WQI the study area is classified into 4 classes good, poor, very poor and unfit for drinking water from south to north. According to SPI model, 20%, 18.7%, 18.7%, 8% and 34.6% of water samples are suitable, slightly, moderately, highly polluted and unfit, respectively from south to north. Based on HRA, Children are the most category endangered with percent 14.7% of the overall samples obtained, followed by females and males with percent 12% and 8%, respectively. This study offers insights into the conservation and management of coastal aquifers’ groundwater supplies. These findings have significant implications for developing strategies and executing preventative actions to reduce water resource vulnerability and related health hazards in West Nile Delta, Egypt.

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Introduction

In recent years, rapid urbanization and population growth, stress on natural resources, and global climate change have caused the demand for water to increase. Sustainable water resource management is becoming increasingly important to meet this demand. It is critical to manage water resources globally since groundwater is essential for meeting human needs and for sustaining life1,2,3,4. Furthermore, unregulated exploitation of groundwater resources has resulted in water shortages over recent decades, which has adversely affected groundwater quality and levels5,6,7,8,9,10. Salinization is a significant issue in many coastal regions globally, particularly in semi-arid and arid areas. It is seen as a crucial and visible issue that threatens future water resources and reduces water quality. Groundwater salinization is a key concern because it restricts water availability for both agricultural and urban needs, impacting the resilience and sustainability of coastal areas. An increase in total dissolved solids (TDS) or chloride (Cl) levels is a clear indicator of salinization11,12,13. The issue of water quality has garnered significant attention in coastal aquifers worldwide due to the aforementioned reasons for example, Thriassion Plain and Eleusis Gulf, Greece14, north Kuwait15, China15, Bangladesh16, Spain17, Mexico18, and others. As groundwater quality is equally important as its quantity, it is crucial to carefully assess it.

Heavy metals pose a toxic threat to human health and ecosystems when their concentrations surpass established limits as they can disrupt ecological systems, endanger human health, and worsen the quality of groundwater. Specific heavy metals, including copper (Cu), zinc (Zn), manganese (Mn), and chromium (Cr), are vital for metabolic processes in traces quantity, but become hazardous at high levels. In contrast, metals such as cadmium (Cd) are toxic even at minimal concentrations19,20. Tackling the presence of trace element-contaminated water resources is crucial for protecting both the ecosystem and human health21. Additionally, understanding the environmental behavior of these trace elements, including their transfer, fate, persistence, and the health risks they pose to consumers through the food chain, is vital. The health impacts of these elements are significantly influenced by factors such as their behavior, specific chemical composition, and binding state. Gaining insight into these factors is the key to assessing the potential risks of trace elements and devising effective strategies to minimize their harmful effects22,23. Controlling and mitigating these harmful effects can be achieved by monitoring heavy metal distribution, concentration, and health risks regularly.

Evaluating groundwater quality is a fundamental approach for ensuring the sustainable management of this essential resource. Various methodologies have been employed to assess groundwater quality, including stoichiometric, graphical, index-based, and inferential chemometric techniques, which are commonly used to analyze and monitor groundwater conditions and hydrogeochemical properties24,25,26. Additionally, advanced tools such as clustering, regression analysis, neural networks, and machine learning algorithms have been incorporated to observe and predict water quality trends effectively27,28,29. Given the variety of hydrochemical criteria, the water quality index (WQI) technique serves as an effective tool for evaluating groundwater quality. Due to its comprehensive calculation method, assessing groundwater quality through multiple hydrochemical parameters is considered a more reliable and robust approach. As a result, WQIs have been widely utilized in groundwater quality assessments. The most frequent techniques for assessing water quality are the WQI for drinking and synthetic pollution index (SPI). The Water Quality Index (WQI) for drinking water and the Synthetic Pollution Index (SPI) are effective tools for measuring and evaluating overall water quality, offering a more comprehensive approach than traditional techniques for evaluating the quality of water. Each of the two types of standard water quality index models (WQI and SPI) measure the cumulative impact of different physicochemical variables on groundwater quality based on weight and rate. Each physicochemical parameter is weighed according to its influence on drinking water quality30,31. Since many people rely on groundwater for drinking and other household purposes, high levels of nitrate in drinking water can result in serious health risks32,33,34. Therefore, health risk assessment (HRA) based on nitrate concentration was applied as drinking water quality criteria35,36,37. Combining water quality indices with GIS techniques provides the most effective method for detecting and visualizing changes in groundwater facies. Several studies have applied water quality indices (WQI and SPI) and HRA methods to evaluate groundwater quality for human use in various regions, and these techniques have proven successful. For instance, studies have been conducted on Makkah Al-Mukarramah Province (Saudi Arabia)38, coastal plain in Nigeria23, dumpsite in Awka (Nigeria)22, El Fayoum depression (Egypt)30, El Kharga Oasis (Egypt)39, and Central Nile Delta Region (Egypt)40.

The quaternary aquifer, coastal aquifer, is considered the main source of groundwater in the area west of Rosetta branch. Based on the previous studies, the groundwater within the study area exposed to several factors, which may lead to increase signs of groundwater quality deterioration. These factors are mainly attributed to anthropogenic activities and sea water intrusion12. Moreover, most previous studies conducted west of the Nile Delta have primarily focused on the morphological and geological features of the terrain41,42,43,44. Additionally, water sources have been examined in terms of their geochemical properties and suitability for irrigation purposes8,12,45,46. However, limited attention has been given to evaluating the quality of groundwater for drinking purposes within the study area. As a result, significant knowledge gaps remain regarding the suitability of groundwater for human consumption in this region.

Based on the aforementioned objectives, this study aimed to evaluate the quality of groundwater for drinking purposes in the region west of the Nile Delta’s Rosetta branch. This study was conducted to develop geospatial maps of physicochemical parameters in groundwater to determine the quality suitability of drinking water. Furthermore, in order to assess the water quality from the aspect of human health, two typical water quality index models are used, namely water quality index (WQI) and synthetic pollution index (SPI). In order to analyze the data concerning water quality, descriptive statistics and correlation matrices were applied. Eventually, human health risk (HRA) was assessed in the study region via contaminated water consumption by adults (males and females) and children. It is expected that this study will assist decision makers in identifying vulnerable zones and optimizing monitoring networks for groundwater quality.

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https://www.nature.com/articles/s41598-025-90477-3?

News Release: New report exposes the vulnerabilities of the Washington metropolitan area’s water supply

According to research by the Interstate Commission on the Potomac River Basin (ICPRB), the region’s water supply could fail to meet the needs of the region as soon as 2030 in the event of an extreme drought.

ROCKVILLE, MD (December 5, 2025): While most people don’t think twice about where their water comes from — or if it will come at all — when they turn on the tap, new research notes that changing weather patterns and increased water demand are putting a strain on the region’s water supply. This may have dire consequences without strong investment in water infrastructure according to a new report by the Interstate Commission on the Potomac River Basin (ICPRB), an organization tasked with producing a report every five years on the region’s water supply.

The report, 2025 Washington Metropolitan Area Water Supply Study – Demand and Resource Availability Forecast for the Year 2050, shows that the region will have plentiful water most years, but there is an increasing chance — up to about 1 percent in 2030 and up to about 5 percent in 2050 — that there will be water shortages. This is when there is not enough water to meet the demands of the water users while still leaving enough water in the Potomac River to protect the sensitive aquatic habitat below Little Falls Dam.

Actual Washington metropolitan area annual water demand (blue dotted line), ICPRB’s 2025 forecast (blue solid line), with actual and forecasted population (gray dotted line).

Actual Washington metropolitan area annual water demand (blue dotted line), ICPRB’s 2025 forecast (blue solid line), with actual and forecasted population (gray dotted line).
(Source: ICPRB)

According to the report, despite exponential growth in the region, overall water use has stayed remarkably stable over the past several decades due to the use of low flow fixtures and appliances. However, the researchers predict an increase in water demand in the coming decades, with a 17 percent increase in water use by 2050.

In addition to more overall use, the river’s flow may be impacted by predicted changes in temperature and precipitation through a process that has been characterized as “hot drought” by ICPRB.

“Results from our study indicate that extreme hydrological droughts may become more severe due to increasing temperatures,” explains Dr. Cherie Schultz, Director of ICPRB’s Section for Cooperative Water Supply Operations on the Potomac.

“A major uncertainty in many regions, including the Potomac, is the response of future stream flow to the competing effects of temperature change and precipitation change. Rising temperatures will tend to decrease flows due to increases in evaporation, while predicted increases in precipitation will tend to increase flows,” continued Dr. Schultz.

“It is changing weather patterns combined with the increase in demand that may be putting the whole system at risk,” states ICPRB Executive Director Michael Nardolilli.

Data center growth is also contributing to the uncertain future of the region’s water supply, both upstream and within the Washington metropolitan area. The study finds that upstream data center water use is expected to grow over time and could become comparable to several established water-using sectors, such as commercial, industrial, and thermoelectric facilities. These estimates are based on grid-connected energy forecasts, which are rapidly evolving as the sector continues to expand. In the Washington metropolitan area, data centers could use as much as 80 million gallons on peak days by 2050. This could signal the growing significance of data centers in the region’s water demand. The report notes that balancing energy, water, regulations, and infrastructure constraints may be needed to strengthen resiliency in this sector. One step forward would be to improve transparency around data center water use.

The majority of the Washington metropolitan area’s water supply is provided by the Potomac River. While most regions have two or more sources of water, the Potomac River is the only source of drinking water for the residents of Washington D.C. and Arlington County.

Two upstream reservoirs, Jennings Randolph and Little Seneca, are available to release water to augment Potomac River flow should the river get too low to meet the region’s demands. In addition, off-Potomac reservoirs, Fairfax Water’s Occoquan Reservoir and WSSC Water’s Patuxent reservoir, are used to partially meet these suppliers’ demands. According to the study, four out of nine modeled scenarios predict that in the event of an extreme drought, the upstream reservoirs will run out of water as early as 2030, indicating that short-term measures should be taken to improve reliability.

Some short-term solutions are already in the works. Improvements in ICPRB’s river flow forecasts can help water resource planners better predict when to release water from upstream reservoirs. A water reuse project recently announced by DC Water, dubbed Pure Water DC, aims to create a more resilient water source for residents of the District. Two drinking water reservoirs currently in the planning stages, Loudoun Water’s Milestone Reservoir (expected operational by 2028) and Fairfax Water’s Edgemon Reservoir (expected operational by 2040), were already included in the report’s calculations.

The U.S. Army Corps of Engineers, Baltimore District, initiated a D.C. Metropolitan Area Backup Water Supply Feasibility Study last fall which could lead the way to possible long-term solutions. However, with federal funding issues hanging in the balance, it is unclear when that study will be completed.

“For nearly 170 years, the Washington Aqueduct has been committed to executing its critical mission to produce safe, reliable, and high-quality drinking water for approximately one million citizens living, working, or visiting the National Capital Region,” said Washington Aqueduct General Manager Rudy Chow. “Increased water resiliency standards are a vital part of our commitment to public health and safety, national security and the wellbeing of local populations. We are in close collaboration with our regional utility partners as we continue our ongoing Washington D.C. Metropolitan Area Backup Water Supply Feasibility Study, aimed at developing coordinated and implementable solutions that ensure abundant water supply, including the identification of a secondary water source and additional water storage capability.”

“We can no longer ignore the fact that parts of the DC region have only one source of drinking water – the Potomac River – and just a one-day back-up of water supply. Today’s release of the 2025 Washington Metropolitan Area Water Supply Study highlights the need to expedite the study so that we can reduce the vulnerability of the DC region from a cutoff of drinking water because of drought or contamination events (both accidental and deliberate),” explained Nardolilli.

“This report confirms the need for innovative and cooperative approaches, as well as funding, to secure the water supply for our region,” said WSSC Water General Manager and CEO Kishia L. Powell. “The Potomac River has provided the vast majority of the region’s drinking water for generations. But climate pressures and growing demand will impact our ability to meet the region’s needs in just a few years. This report makes clear that we need to continue with substantial investments to safeguard public health, enhance reliability and resiliency, and ensure the long-term economic vitality of the region.”

An earlier study released by ICPRB found that a significant water supply disruption could result in losses of almost $15 billion in gross regional product and hundreds of millions in tax losses, all within the first month.

“For nearly 50 years Fairfax Water, WSSC Water, the Washington Aqueduct and ICPRB have been working together to ensure adequate water supply for the Washington Metropolitan Region now and into the future” said Fairfax Water General Manager and CEO Jamie Bain Hedges. “This study further advances our collective mission to supply life’s most essential service for decades to come.”

The water supply study released today is conducted every five years by the Section for Cooperative Water Supply Operations on the Potomac (CO-OP) of the Interstate Commission on the Potomac River Basin (ICPRB) on behalf of the three major water suppliers: Fairfax Water, WSSC Water, and the Washington Aqueduct. This is the first year that the study has explored the impacts of data centers on the water supply.

Press Release

New Study: 21 Global Water Scarcity Hotspots Identified, Classified into 7 Hotspot “Clusters” with Shared Water Challenges

New research from Utrecht University, supported by the National Geographic Society’s World Water Map and Freshwater Initiative, found common drivers of water scarcity can help inform common solutions

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Photo by Charlie Hamilton James

WASHINGTON, D.C. (April 25, 2024) – A new study released today identifies 21 global water scarcity “hotspots,” where there is a significant “water gap” between human demand for water and renewable available supply. The team of Utrecht University researchers analyzed each of the 21 hotspots to determine what’s driving water scarcity at each location. Hydroclimatic change, population growth, and agricultural, domestic, and municipal water use are the biggest pressures affecting both the quality and quantity of available water, researchers found. The study in Environmental Research Letters also classifies the 21 hotspots into seven “clusters,” based on common drivers of water scarcity.

About one third of the global population is affected by water scarcity for at least one month per year. In these areas, the overuse of freshwater resources can lead to a “water gap” and threat of depletion, making them global water scarcity hotspots, said the study, which is supported by the National Geographic Society’s World Water Map and Freshwater Initiative.

Researchers identified the 21 hotspots through a combined approach of hydrological modeling and a literature review of 300 case studies. Hotspots were classified as water provinces where the water gap exceeds 0.015 meters per year. Additionally, to identify and characterize hotspot clusters by similarities and differences, the team applied a Drivers, Pressures, States, Impacts and Responses (DPSIR) framework to the literature.

Example of the most important water scarcity Drivers, Pressures, States, Impacts and Responses (DPSIR) in the Indus Basin. The colors of the text boxes with system processes correspond to the respective DPSIR component from the legend in the bottom right. Black arrows in the legend indicate how DPSIR components affect each other. Colored arrows in the figure give spatial direction to corresponding system processes. Image courtesy of Utrecht University.

Myrthe Leijnse, Utrecht University

“We started with two questions: where does water scarcity occur, and why is it happening? While we found water scarcity has similar drivers in some hotspots, the impacts on people, ecosystems, and economies – as well as societal and policy responses – could vary widely place to place,” said Myrthe Leijnse, the lead author of the study and a researcher at Utrecht University. “We hope this study demonstrates to policymakers that if there are common contributors to water scarcity, there could be common solutions to addressing it.”

The seven “hotspot” clusters are:

  1. Water treatment and desalination: Arabian Peninsula. Unlike other hotspots, this region faces a unique combination: low natural water availability (highlighted in 89% of case studies) and high per capita water consumption (42%), leading to groundwater depletion and reliance on unconventional water sources (desalination and water treatment). Economic growth from oil and natural gas discovery has also fueled urbanization and population growth, further intensifying water demand.
  2. Hydroclimatic change: Central Chile, Spain, Murray-Darling (Australia), Japan. These hotspots have faced consecutive droughts and a decline of total annual rainfall. At the same time, these hotspots have effective acts and agreements that support sustainable use of water resources (including water treatment, water rights, and increased storage capacity). Unlike most other hotspots, population growth is not a major driver of water scarcity in these locations.
  3. Agricultural water use: North China Plain, Central Valley California, US High Plains, White Nile Sudan, Nile Delta, Italy, Greece, and Turkey. This is the largest cluster by number of hotspots, containing eight of the 21. Their single commonality is high agricultural water use (mentioned in 29-100% of case studies).
  4. Population growth: Indus and Ganges River Basins: The Indus and Ganges River Basins have experienced rapid population growth over the last decade (reported in 40-67% of case studies), impacting society and the ecosystem. Water scarcity has led to reduced food production (24-33%), conflict and migration (28-33%), and health concerns (17-56%). The lack of water regulation has also resulted in unregulated private wells and subsequent groundwater depletion (52-61%).
  5. Surface and groundwater depletion: Coastal Peru and Iran. Peru and Iran are the only hotspots where both surface and groundwater depletion are reported in over 60% of case studies. Both hotspots report contamination and salinization of water resources. Conflict and rural-urban migration (45-50%) are also prevalent due to water scarcity and inequality of water supply.
  6. Land subsidence: Mexico, Java (Indonesia), and Vietnam. All show above average values of industrial (30-71%), municipal (40-75%) and agricultural (70-100%) water use. While these values are also reported in other clusters, Mexico, Java and Vietnam have one common impact that is unique compared to other hotspots: land subsistence (10-27%), the gradual settling or sudden sinking of the Earth’s surface. This is likely due to groundwater overexploitation.
  7. Virtual water trade: Thailand. In Thailand, virtual water trade (43%) is a significant factor driving water scarcity. Thailand is one of the world’s biggest rice exporters, shipping about one third of its rice production. However, case studies had limited information on policy responses to address water scarcity in Thailand.

Myrthe Leijnse, Utrecht University

“Water scarcity doesn’t always look like a lake or river drying up in an arid climate, but can also manifest itself in wetter climates as temporarily low streamflow or falling groundwater levels. It has many diverse, complex drivers, whether that’s producing water-intensive crops or goods for global trade, rapid population growth, or inefficient use of water in our towns and cities,” said Marc Bierkens, National Geographic Explorer and professor of hydrology at Utrecht University.

Niko Wanders, project lead and associate professor of hydrological extremes at Utrecht University, adds, “by zooming in on these hotspots, we can understand the development of water scarcity in a regional context. We hope these insights can help us find better targeted solutions to alleviate water scarcity. Also, by comparing drivers and solutions between hotspots, we hope to equip policymakers with insights to help close the water gap.”

The Society’s World Freshwater Initiative supports grantees in science, conservation, education, and storytelling, who are illuminating water scarcity issues – as well as sustainable solutions – in these hotspot areas and beyond.

“The identification of these 21 water scarcity hotspots is a critical addition to our understanding of global water and how people, wildlife, and nature use it. A complement to the World Water Map, the hotspots help tell the story of our irreplaceable freshwater resource and are part of our ongoing commitment to illuminate and protect the wonder of our world,” said Alex Tait, The Geographer at the National Geographic Society. “This study embodies the power of the geographic approach: observe the world around us, gather and analyze data, and generate powerful insights about how people interact with water.”

Myrthe Leijnse, Utrecht University

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https://news.nationalgeographic.org/new-study-21-global-water-scarcity-hotspots-identified-classified-into-7-hotspot-clusters-with-shared-water-challenges/?