1. Properties: white powder, a mixture of zinc sulfide and barium sulfate.

better

Genotoxicity refers to the ability of a chemical substance to damage DNA , the genetic material of cells. As genotoxicity may lead to carcinogenic effects, it is essential to assess the potential genotoxic effect of a substance to conclude on its safety.  

CNNC Huayuan Titanium Dioxide Co., Ltd. (hereinafter referred to as the company or CNNC TiO2 is a famous titanium dioxide manufacturer in China and a listed company on the Shenzhen Stock Exchange. Its main products are high-grade rutile titanium dioxide, which are widely used in coatings, plastics, rubber, In ink, paper and other fields, it is known as “industrial monosodium glutamate”, and its application prospects are very broad.

Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

In food, titanium dioxide is often used as an artificial color additive. Tasha Stoiber, senior scientist at the consumer health nonprofit Environmental Working Group, says titanium dioxide can generally be thought of as a paint primer – it often goes on a hard-shelled candy like Skittles before the color is added to give it a uniform shine.

Neutral

Lithopone: an alternative to titanium dioxide

TiO₂ has been well accepted in the food industry and can be found as the E171 additive in various food products, mainly for whitening and texture. It is present in some cottage and Mozzarella cheeses, horseradish cream and sauces, lemon curd, and in low-fat products such as skimmed milk and ice-cream. Even if the product is labelled as containing E171, no information is usually given about the quantity, particle size and particle structure. FDA claims that TiO₂ may be safely used as a colour additive for colouring foods in quantities up to 1 % by weight of the food. Interestingly, TiO₂ is frequently declared as a “natural colouring agent” and is therefore well accepted by consumers.

Additionally, the growing emphasis on sustainability within the automotive industry influences the demand for environmentally friendly tire production methods. TiO2, being a non-toxic and eco-friendly compound, aligns with these sustainability goals, making it an attractive option for manufacturers looking to reduce their environmental footprint.

JECFA previously assessed titanium dioxide at its 13^th meeting, at which time the expert committee assigned a “not specified” ADI for the additive due to an absence of significant absorption and a lack of toxicological effects in the available experimental animal and human studies. Since its original evaluation by JECFA, titanium dioxide has become a public point of contention, with its ban being introduced (and then subsequently withdrawn) in California legislation in 2023, a legal battle playing out in the EU over the additive’s ban and classification as a carcinogen in 2022, and the European Food Safety Authority (EFSA) calling titanium dioxide unsafe. However, supporters of titanium dioxide say that claims about its dangers are founded in unreliable studies, and some recent research has supported its safety as a food additive.

Let’s break the risk down further.  

Lithopone, C.I. Pigment White 5, is a mixture of inorganic compounds, widely used as a white pigment powder. It is composed of a mixture of barium sulfate and zinc sulfide. These insoluble compounds blend well with organic compounds and confer opacity. It was made popular by the cheap production costs, greater coverage. Related white pigments include titanium dioxide, zinc oxide (zinc white), zinc sulfide, and white lead.