At the present JECFA meeting, the committee considered additional toxicological studies relevant to the safety assessment of the chemical that investigated its toxicokinetics, acute toxicity, short-term toxicity, long-term toxicity and carcinogenicity, genotoxicity, and reproductive and developmental toxicity, as well as special studies addressing its short-term initiation/promotion potential for colon cancer. The experts acknowledged that a large number of toxicological studies have been conducted using test materials, including nanoparticles, having size distributions and physico-chemical properties not comparable to real-world uses of titanium dioxide as a food additive. The studies on non-representative materials were evaluated by JECFA, but the committee concluded that such studies are not relevant to the safety assessment of the additive.

The toxicity of P25TiO₂NPs was evaluated in both prokaryotic (Fig. 3) and eukaryotic cells (Fig. 4). The XTT assay was chosen to measure the cell viability in bacterial cultures of MSSA, a normal skin microbiota microorganism. The reduction in the viability of samples with bare NPs is notorious, possibly due to the described ROS production from the interaction of P25TiO₂NPs with light [37]. This effect seems to be avoided when they are functionalized with vitamin B2. Also, the most concentrated vitaminB2@P25TiO₂NPs sample (0.2 mg/mL) shows up to 60% more absorbance after 6 h compared to the bare NPs (due to normal cell replication). This may indicate that the antioxidant effect of the vitamin B2 coating is greater than the oxidation damage produced by the NPs. This protective capacity could be attributed to the glutathione redox cycle and the conversion of reduced riboflavin to its oxidized form [38]. Values of cell viability greater than 100% are not rare and could be understood because the XTT assay actually measure metabolic activity when reducing the tetrazole to formazan. It is usually assumed that conversion is dependent on the number of viable cells, but it could also be related to an expected increased enzymatic activity when cells are exposed to small doses of some new substance. Further analysis showed that this effect was not the only one responsible for better cell viability of vitaminB@P25TiO₂NPs treated samples.

This article discusses the discovery of phosphorescent lithopone on watercolor drawings by American artist John La Farge dated between 1890 and 1905 and the history of lithopone in the pigment industry in the late 19th and early 20th centuries. Despite having many desirable qualities for use in white watercolor or oil paints, the development of lithopone as an artists’ pigment was hampered by its tendency to darken in sunlight. Its availability to, and adoption by, artists remain unclear, as colormen's trade catalogs were generally not explicit in describing white pigments as containing lithopone. Further, lithopone may be mistaken for lead white during visual examination and its short-lived phosphorescence can be easily missed by the uninformed observer. Phosphorescent lithopone has been documented on only one other work-to-date: a watercolor by Van Gogh. In addition to the history of lithopone's manufacture, the article details the mechanism for its phosphorescence and its identification aided by Raman spectroscopy and spectrofluorimetry.

Stability and darkening:

Lithopone is rather nontoxic, due to the insolubility of its components. It has been used in medicine as a radiocontrast agent. Lithopone is allowed to be in contact with foodstuffs in the US and Europe.

Basic Information

Titanium is a metal element found naturally in the environment. When it's exposed to oxygen in the air, it forms titanium oxides that are contained in many minerals, sands, soils, and dusts.

A steep decline in the prices of titanium dioxide was observed in the second half of 2022 as the erratic energy costs along with rising covid cases affected the market negatively. In addition to this, the decreased offtakes from paints and coating industries, weak economic growth, and strict restrictions imposed to deal with the resurgence of covid cases further aided the declining trajectory of titanium butoxide prices.

While the conclusions of the EU expert panel were considered in this report, Health Canada's Food Directorate conducted its own comprehensive review of the available science. This included evaluating new scientific data that addressed some of the uncertainties identified by the EU expert panel and were not available at the time of their review.    

Additional Health Concerns Linked to Titanium Dioxide

In order to achieve the same solids content, the larger filler and the binder should be reduced if necessary.  

Despite a bullish trends ruling the market for the bulk of the period, the North American market had mixed sentiments in the fourth quarter of 2021. This was mostly due to the adequate pushback from the supply-demand imbalance, which was further compounded by rising natural gas prices, which had taken a proper toll on the future production of numerous minerals, including titanium dioxide. An increase in COVID instances had prompted concerns in ore feedstock. As a result, during the fourth quarter of 2021, the FD UGSC (USA) quarterly average negotiations for the chemical CP Rutile Grade were finalised at USD 4434 per tonne.

What's the deal with titanium dioxide?