Is titanium dioxide harmful to the environment?

Nano-TiO2 particles released into surface and marine waters may affect aquatic ecosystems. These reactive particles undergo physical, chemical, and biological transformations that influence their behavior and toxicity. Studies show they accumulate in aquatic organisms such as phytoplankton, fish, and filter-feeding mollusks, affecting organism health and food webs. Phytoplankton, a key link in the marine food chain, can absorb nano-TiO2 particles, whose UV-driven photoreactivity produces harmful oxidative stress.

Nano-TiO₂ interacts with heavy metals (Cu, Zn, Cd, As) and organic pollutants, increasing their toxicity to marine wildlife. This interaction raises bioaccumulation in marine organisms, disrupting the food chain and posing a risk to human health through consumption of contaminated fish and seafood. Research shows TiO₂ exposure, even at 6.3 mg/L—half the maximum UV filter concentration allowed in sunscreens—can cause loss of symbiotic microalgae in corals. This leads to bleaching and reduced reef health. These concentrations also drive TiO₂ bioaccumulation in coral tissues.

Titanium dioxide often enters the environment through agricultural products, pigments, or food additives and accumulates in soils, where it contacts plants. Once in soil, nano-TiO2 particles interact with soil properties such as pH, microbial communities, and enzymes. These interactions affect particle mobility and bioavailability. Studies show that nano-TiO2 can disrupt the diversity and activity of microorganisms essential to nutrient cycles, including those that fix nitrogen and oxidize methane, by inhibiting their growth.

Moreover, these particles can enter plant cells, affecting photosynthesis, metabolism, and gene expression. At high concentrations (> 2.0 mg/g soil), they reduce the activity of essential enzymes, which can impair plant growth and alter the composition of bacteria that support plant development, compromising biodiversity and ecosystem function.

The nano-TiO2 are widely used in various products but also pose environmental risks. These particles resist degradation and can remain in the environment for years. Their small size allows rapid spread, raising the risk of toxic effects in aquatic ecosystems. Scientists study the impact of these nanoparticles on ecosystems and their accumulation in different species. Much remains unknown about their long-term effects on biodiversity, and further research is essential to understand these risks.

Consequently, TiO₂ can have negative environmental effects in nanoparticle form. It is essential to find solutions to improve its management. That requires clear regulations to limit its use and measures to prevent its release into the environment. Companies handling TiO₂ must also comply with strict safety rules.