Titanium Dioxide Nanoparticles Detected in Milk Despite European Food Ban

Background:
Titanium dioxide (TiO₂) nanoparticles (NPs) are produced on a massive scale for diverse industrial uses, including paints, coatings, paper, plastics, cosmetics, pharmaceuticals, solar cells, and catalysts. They can enter the environment both unintentionally—through the wear, degradation, and disposal of Ti-containing products—and intentionally, such as when used in fertilizers or wastewater treatments.

Due to their persistence, TiO₂ nanoparticles are now detected in virtually all environmental compartments, including in wildlife and humans. Concerns over their toxicity have been well-documented. The International Agency for Research on Cancer (IARC) classifies TiO₂ as a possible human carcinogen when inhaled. In February 2022, the European Union banned its use in food products (EU Directive 2022/63) over suspected health risks. Despite this, it remains common in everyday items such as toothpaste, sunscreen, makeup, medicines, plastics, paper, and paints.

The new study:

Photo: Glass of cow milk  (CC by 2.0)

To better understand the real-world exposure of humans and animals to TiO₂ nanoparticles, scientists in France measured their presence in human and animal milk, as well as in infant formula. Milk is a critical food for newborns and serves as a direct indicator of maternal exposure.

Published in Science of the Total Environment, the study reveals that Ti-containing particles were present in all animal milk samples and in 83% of infant formulas tested. Using advanced analytical tools—including single-particle inductively coupled plasma mass spectrometry, X-ray fluorescence, and micro-XANES spectroscopy—the researchers found particle concentrations reaching billions per liter, with most particles measuring under 100 nanometers.

Mineral analysis showed rutile as the dominant crystalline form of TiO₂, alongside anatase, ilmenite, and pseudobrookite. Human breast milk samples displayed significant variation—up to a 15-fold difference in nanoparticle levels—suggesting differences in environmental exposure, diet, or metabolism. The detection of localized “hot spots” of titanium within milk further underlines the need for stricter monitoring and source tracing.


Implications: