Clean water is a cornerstone of human health and environmental well-being. Yet, as our world becomes increasingly industrialized, the chemicals we use in agriculture, pharmaceuticals, and manufacturing are seeping into water supplies, posing invisible threats to both people and ecosystems. A groundbreaking study published in Nature Communications offers a fresh perspective on tackling this challenge. By integrating riverbank filtration with advanced reverse osmosis—and adopting a holistic framework called the WEALTH approach (Water-Environment-Health Nexus)—researchers propose a path to cleaner water that benefits public health and the planet.

The Hidden Threat: Chemicals of Emerging Concern (CECs)

Chemicals of Emerging Concern (CECs) are a diverse group of pollutants that include pesticides, pharmaceuticals, industrial additives, and even byproducts from water disinfection. These substances are increasingly detected in drinking water worldwide, often at trace levels (nanograms to micrograms per liter). While individually they may seem harmless, their cumulative effects are alarming. Studies link long-term exposure to CECs with cancer, hormonal disruptions, and developmental issues, even at extremely low concentrations.

The problem is growing: over 75,000 chemicals are in commercial use today, and global chemical sales are projected to double by 2030. Conventional water treatment plants, designed decades ago, struggle to remove these modern contaminants. Worse, some treatments inadvertently create new risks, such as toxic disinfection byproducts (DBPs) like chloroform.

Two Systems, Two Outcomes: RBF-ET vs. RBF-RO

The study compares two water purification systems at a plant in Kamerik, Netherlands:

1. RBF-ET (Riverbank Filtration + Extended Treatment): A conventional system combining natural filtration through riverbank soil with processes like activated carbon filters and UV disinfection.

2. RBF-RO (Riverbank Filtration + Reverse Osmosis): An advanced system where riverbank-filtered water undergoes high-pressure reverse osmosis (RO) to remove even the smallest contaminants.

Process flow diagram illustrating the construction of alternative water production systems. a, riverbank filtration-extended treatment (RBF-ET) system. b, riverbank filtration-reserve osmosis (RBF-RO) system.

Health Benefits: Saving Lives, One Drop at a Time

To measure health impacts, researchers used Disability-Adjusted Life Years (DALYs), a metric that quantifies years of healthy life lost due to disease or disability. The World Health Organization (WHO) sets a tolerable threshold of 1.00 × 10⁻⁶ DALYs per person annually for drinking water.

• Source water alone failed miserably: 0% of cancer risks and only 11% of non-cancer risks met the WHO threshold.

• RBF-ET eliminated non-cancer risks entirely but left cancer risks above acceptable levels.

• RBF-RO excelled: 100% of simulations for both cancer and non-cancer risks fell below the WHO limit.

Switching to RBF-RO could prevent up to 85% of non-cancer diseases and eliminate cancer risks linked to CECs. Key contaminants like DBPs and pesticides were drastically reduced, showcasing RO’s ability to tackle even low-concentration, high-toxicity chemicals.

Environmental Trade-Offs: A Double-Edged Sword

While RBF-RO outperforms conventional systems in health outcomes, its environmental footprint is nuanced. A Life Cycle Assessment (LCA) revealed:

• Reductions in 8 of 10 impact categories, including fossil fuel depletion (-14%), freshwater ecotoxicity (-12%), and global warming (-1%).

• A 53% increase in marine eutrophication, likely due to nitrogen emissions from RO membrane production and energy use.

• Higher terrestrial ecotoxicity from CO₂ used in post-treatment remineralization and truck transport of materials.

Optimizing the System: Smarter Tech, Cleaner Energy

The study proposes solutions to mitigate these downsides:

• Extend RO membrane lifespan: Doubling durability could cut marine eutrophication by 24%.

• Recover hydraulic energy: Using turbines to capture energy from high-pressure brine reduces energy demands.

• Shift to renewable energy: In countries like Canada and Brazil, where hydropower dominates, RBF-RO’s environmental impacts plummet. Conversely, coal-dependent nations like China and India face higher emissions.

The WEALTH Approach: A Triple Win for Water, Health, and Nature

The study’s most innovative contribution is the WEALTH framework, which integrates three pillars:

1. Water Quality: Advanced purification to remove CECs.

2. Environmental Sustainability: Minimizing energy use, chemical additives, and emissions.

3. Public Health: Reducing disease burdens from contaminated water.

Traditionally, these goals have been pursued in isolation. For example, RO effectively removes contaminants but often at the cost of high energy use. The WEALTH approach forces policymakers and engineers to weigh trade-offs and synergies. Think of it as a three-legged stool: neglecting one leg destabilizes the entire system.

Conceptual framework illustrating the interactions among clean water
supply, human health protection, and environmental sustainability goals
(“WEALTH”).

Global Lessons and Local Realities

The effectiveness of RBF-RO hinges on regional factors:

• Climate and Hydrology: Humid regions with abundant surface water (e.g., the Netherlands) benefit from riverbank filtration. Arid areas might prioritize groundwater RO or desalination.

• Energy Mix: Renewable energy transforms RBF-RO into a climate-friendly solution. In contrast, coal-heavy grids exacerbate its carbon footprint.

• Economic Capacity: RO systems are costly to install and maintain. Developing nations may need phased strategies, prioritizing high-risk contaminants first.

Limitations and the Road Ahead

The study acknowledges gaps:

• PFAS Exclusion: Persistent "forever chemicals" like PFAS were not analyzed due to data limitations, despite their known risks.

• Dynamic Water Systems: Real-world variations in water quality and treatment interactions require more adaptive models.

• Chemical Mixtures: The additive risk model assumes no interactions between CECs, which may underestimate complex effects.

Future research should explore hybrid systems (e.g., wetlands + engineered filters) and refine toxicity assessments for emerging contaminants.

Why This Matters

Clean water is not just an engineering challenge—it’s a societal imperative. The WEALTH approach offers a blueprint for aligning technological innovation with ecological and health priorities. For policymakers, this means investing in renewable energy to power water treatment and adopting stricter regulations on CECs. For communities, it underscores the need to safeguard natural systems like rivers and aquifers that provide "free" filtration services.

As chemical pollution escalates, solutions like RBF-RO and the WEALTH framework remind us that sustainability isn’t a single technology or policy. It’s a balanced, interconnected vision where clean water, healthy populations, and a thriving environment coexist.

Read the full study: Leveraging the water-environment-health nexus to characterize sustainable water purification solutions
Nature Communications | Published online: 02 February 2025

For media inquiries or further details, contact the corresponding author Professor Xu Wang at wangxu2021@hit.edu.cn.