Hidden Dangers: Uncovering Fine Microplastics in EU Drinking Water

A recent study published in PLoS Water identified high concentrations of fine microplastics (MPs) in bottled and tap water (1). Oskar Hagelskjaer, CEO and Founder of Microplastic Solutions, an analytical laboratory specializing in microplastics, completed this research alongside a team from the Centre de Recherche sur la Biodiversité et l’Environnement (CRBE) at Université de Toulouse. Findings call into question EU Directive 2020/2184, a regulatory framework that establishes the standards for potable water, Hagelskjaer said (1).

In the study, Hagelskjaer and the team used advanced automated Raman microspectroscopy to analyze ten bottled water brands and one municipal tap water sample, revealing the presence of MPs less than 20 μm and as small as 1 μm. MPs between 1–20 μm are not included in the EU water quality guidelines, but they are ubiquitous in potable and bottled water (1). These smaller MPs, because of their size, are more likely to enter the human intestines, which increases the risk of these MPs entering the bloodstream, the researchers wrote in the study (1).

Closeup image of a young woman holding a glass of water to drink. | Image Credit: © Farknot Architect - stock.adobe.com

The EU Directive 2020/2184 was drafted to protect humans from unsafe drinking water. The directive includes provisions of quality standards, risk assessment, and risk management of the areas for the abstraction points of water (2). The directive does not apply to natural mineral waters or water serving as medicine (2). It addresses MP concentration between 20–5000 μm (1,2). However, in Hagelskjaer’s team’s study, they found that most MP contamination in drinking was less than 20 μm, and as a result, the directive excludes most of the MP contamination in drinking water.

“We had the protocols and the instrumentation to reach that range, so that’s what we did,” Hagelskjaer said. “It’s generally accepted that smaller particles are hazardous and dangerous for human health, so for us it seemed obvious to analyze them.”

The researchers, in total, found that MP concentrations in bottled water ranged from 19 to 1,154 MPs per liter, with a mean concentration of 306 ± 316 MPs per liter (1). Municipal tap water contained 413 MPs per liter, surpassing the MP levels in 8 of the 10 bottled water samples (1). Importantly, 98% of all detected MPs were smaller than 20 μm, with 94% measuring less than 10 μm (1).

Once they determined the concentrations of MPs, the researchers then identified the particles. In their analysis, the team identified 17 unique polymer types. These included polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) (1). Surprisingly, PET, despite being the material used for bottled water containers, accounted for only a small fraction of MPs in most samples, suggesting that container material alone does not significantly contribute to MP contamination (1).

The main question the researchers posed in the study is what their findings mean for the EU, who adhere to this standard. The MP concentrations found in Toulouse tap water align with similar treated surface water sources in Norway and the Czech Republic, but they are approximately ten times higher than levels in groundwater-sourced drinking water in Denmark (1). As a result, the extent of this problem varies between all EU countries, with some having higher concentrations of MPs than others.

“They tried to do it with positive intent, to set the bar at 20 microns, but I think it’s going to be more impractical,” Hagelskjaer said. “All our evidence points toward microplastics under 20 microns being the ones of worry, then why not just go to 1–20, because it just seems a bit backwards.”

By analyzing over half a million individual particles across samples, the team demonstrated the feasibility of incorporating 1–20 μm MPs into routine water quality assessments. The protocol accounted for procedural blanks and recovery corrections, ensuring accurate results (1). The authors advocate for updates to the directive to include MPs smaller than 20 μm, ensuring that public health risks associated with fine MPs are addressed (1).

Given the ubiquity of microplastics in potable water, the study raises awareness about potential health impacts while providing a roadmap for more inclusive and accurate monitoring protocols. As global attention on plastic pollution intensifies, Hagelskjaer’s work is a critical reminder that small particles can have big consequences (1).

References

1. Hagelskjaer, O.; Hagelskjaer, F.; Margenat, H.; et al. Majority of Potable Water Microplastics Are Smaller Than the 20 μm EU Methodology Limit for Consumable Water Quality. PLoS Water 2025, 4 (1), e0000250. DOI: 10.1371/journal.pwat.0000250
2. Food and Agriculture Organization of the United Nations. FAOLEX Database. FAO.org. Available at: https://www.fao.org/faolex/results/details/en/c/LEX-FAOC201243/ (accessed 2025-01-23)