Until relevant toxicological and human exposure data that would enable reliable risk assessment are obtained, TiO₂ nanoparticles should be used with great care.

Sulphate process. The ilmenite is reacted with sulphuric acid giving titanium sulphate and ferric oxide. After separation of ferric oxide, addition of alkali allows precipitation of hydrous titanium dioxide. The washed precipitate is calcined in a rotary kiln to render titanium dioxide. The nucleation and calcination conditions determine the crystalline structure of titanium dioxide (e.g. rutile or anatase).

In an early study Jani et al. administred rutile TiO₂ (500 nm) as a 0.1 ml of 2.5 % w/v suspension (12.5 mg/kg BW) to female Sprague Dawley rats, by oral gavage daily for 10 days and detected presence of particles in all the major gut associated lymphoid tissue as well as in distant organs such as the liver, spleen, lung and peritoneal tissue, but not in heart and kidney. The distribution and toxicity of nano- (25 nm, 80 nm) and submicron-sized (155 nm) TiO₂ particles were evaluated in mice administered a large, single, oral dosing (5 g/kg BW) by gavage. In the animals that were sacrificed two weeks later, ICP-MS analysis showed that the particles were retained mainly in liver, spleen, kidney, and lung tissues, indicating that they can be transported to other tissues and organs after uptake by the gastrointestinal tract. Interestingly, although an extremely high dose was administrated, no acute toxicity was observed. In groups exposed to 80 nm and 155 nm particles, histopathological changes were observed in the liver, kidney and in the brain. The biochemical serum parameters also indicated liver, kidney and cardiovascular damage and were higher in mice treated with nano-sized (25 or 80 nm) TiO₂ compared to submicron-sized (155 nm) TiO₂. However, the main weaknesses of this study are the use of extremely high single dose and insufficient characterisation of the particles.

Drivers

The other form in which titanium dioxide is produced is as an ultrafine (nanomaterial) product. This form is selected when different properties, such as transparency and maximum ultraviolet light absorption, are needed, such as in cosmetic sunscreens.

Made Safe only allows titanium dioxide as part of sunscreen solutions and diaper creams; all titanium dioxide must be non-nanoparticle. Made Safe does not allow titanium dioxide in any other personal care or household products.

1. What is titanium dioxide?

Algaecidal effect of Lithopon: After 5 years of exposure to weathering in Alpen (Lower Rhine)  

Report Coverage:

In recent years, environmental concerns have shaped the way lithopone is produced and used. Suppliers are now more attentive to the sustainability aspect of their operations, ensuring that lithopone is sourced from eco-friendly processes. Many suppliers have adopted responsible mining practices and have invested in technologies that reduce waste and emissions during production. This shift not only appeals to environmentally-conscious consumers but also helps manufacturers comply with stringent regulations regarding product safety and environmental impact.

FDA’s response

Durabo White, 24.5 per cent zinc sulphide, 51 per cent barium sulphate, 18 per cent white clay, 5.5 per cent infusorial earth.

“Unlike some other chemicals used in food, titanium dioxide has no nutritive, preservative, or food safety function—its use is purely cosmetic,” said CSPI principal scientist for additives and supplements, Thomas Galligan. “The prospect of titanium dioxide nanoparticles damaging DNA is concerning enough for us to recommend consumers avoid foods that have it.”