ZnSO4 – BaS ➔ BaSO4*ZnS

The FDA is reviewing the safety of titanium dioxide in response to an April petition from EWG and other environmental and public health groups. This is the FDA’s first comprehensive review of titanium dioxide since 1973.

Used for coloring paint, ink, rubber, etc. Inorganic white pigments are widely used as white pigments in plastics such as polyolefin, vinyl resin, ABS resin, polystyrene, polycarbonate, nylon and polyformaldehyde, as well as paints and inks. It is less effective in polyurethane and amino resins, and less suitable in fluoroplastics. It is also used for coloring rubber products, papermaking, varnished cloth, oilcloth, leather, watercolor paints, paper, enamel, etc. Used as an adhesive in the production of electric beads.

Titanium dioxide A1 adopts good oxidation process, composite inorganic coating and organic treatment, and has the characteristics of excellent particle size distribution, high brightness and high weather resistance. It is recommended for high gloss and high weather resistance coatings, inks and outdoor polymer materials.

Of the two methods of extraction, the sulphate process is currently the most popular method of producing TiO₂ in the European Union, accounting for 70 percent of European sources. The remaining 30 percent is the result of the chloride process. On a global level, it is estimated about 40-45 percent of the world’s production is based on the chloride process.

Historical references

Toxic effects of TiO₂ NPs on aquatic organisms

Food quality

Nano, or ultrafine, TiO₂ comprises primary particles sized less than 100nm. In this grade, titanium dioxide is transparent (colourless) and boasts improved UV scattering and absorbing properties compared with larger particle-size pigmentary TiO₂.

The skin of an adult person is, in most places, covered with a relatively thick (∼10 μm) barrier of keratinised dead cells. One of the main questions is still whether TiO₂ NPs are able to penetrate into the deeper layers of the skin. The majority of studies suggest that TiO₂ NPs, neither uncoated nor coated (SiO₂, Al₂O₃ and SiO₂/Al₂O₃) of different crystalline structures, penetrate normal animal or human skin. However, in most of these studies the exposures were short term (up to 48 h); only few long-term or repeated exposure studies have been published. Wu et al.83 have shown that dermal application of nano-TiO₂ of different crystal structures and sizes (4–90 nm) to pig ears for 30 days did not result in penetration of NPs beyond deep epidermis. On the other hand, in the same study the authors reported dermal penetration of TiO₂ NPs with subsequent appearance of lesions in multiple organs in hairless mice, that were dermal exposed to nano-TiO₂ for 60 days. However, the relevance of this study for human exposure is not conclusive because hairless mice skin has abnormal hair follicles, and mice stratum corneum has higher lipid content than human stratum corneum, which may contribute to different penetration. Recently Sadrieh et al. performed a 4 week dermal exposure to three different TiO₂ particles (uncoated submicron-sized, uncoated nano-sized and coated nano-sized) in 5 % sunscreen formulation with minipigs. They found elevated titanium levels in epidermis, dermis and in inguinal lymph nodes, but not in precapsular and submandibular lymph nodes and in liver. With the energy dispersive X-ray spectrometry and transmission electron microscopy (TEM) analysis the authors confirmed presence of few TiO₂ particles in dermis and calculated that uncoated nano-sized TiO₂ particles observed in dermis represented only 0.00008 % of the total applied amount of TiO₂ particles. Based on the same assumptions used by the authors in their calculations it can be calculated that the total number of particles applied was 1.8 × 10¹³ /cm² and of these 1.4 x10⁷/cm² penetrated. The surface area of skin in humans is around 1.8 m²  and for sun protection the cream is applied over whole body, which would mean that 4 week usage of such cream with 5 % TiO₂ would result in penetration of totally 2.6 × 10¹⁰ particles. Although Sadrieh et al.concluded that there was no significant penetration of TiO₂ NPs through intact normal epidermis, the results are not completely confirmative.

Are there any other products where you use titanium dioxide?

For research published in Archives of Toxicology in 2020, scientists fed one group of mice a solution containing titanium dioxide for one month, and compared it to those that did not receive the additive. They found “the richness and evenness of gut microbiota were remarkably decreased and the gut microbial community compositions were significantly changed” in the titanium dioxide group when compared with the control group. The tests also revealed that the titanium dioxide exposure could cause locomotor dysfunction, or mobility issues “by elevating the excitement of enteric neurons, which might spread to the brain via gut-brain communication by vagal pathway.” The researchers concluded: “These findings provide valuable insights into the novel mechanism of TiO2NP-induced neurotoxicity. Understanding the microbiota-gut-brain axis will provide the foundation for potential therapeutic or prevention approaches against TiO2NP-induced gut and brain-related disorders.”