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Resumo–Este artigo discute a descoberta de litopônio fosforescente em desenhos de aquarela do artista americano John La Farge datados de entre 1890 e 1905 e a história do litopônio na indústria de pigmento no final do século XIX e início do século XX. Apesar de ter muitas qualidades desejáveis para o uso em aquarela branca ou tintas a óleo, o desenvolvimento do litopônio como um pigmento de artistas foi prejudicado por sua tendência a se escurecer na luz solar. Sua disponibilidade para e uso por parte de artistas ainda não está clara, uma vez que os catálogos comerciais dos vendedores de tintas geralmente não eram explícitos na descrição de pigmentos brancos como algo que contém litopônio. Além disso, o litopônio pode ser confundido com o branco de chumbo durante o exame visual e sua fosforescência de curta duração pode ser facilmente perdida pelo observador desinformado. O litopônio fosforescente foi documentado em apenas um outro trabalho até hoje: uma aquarela de Van Gogh. Além da história da manufatura do litopônio, o artigo detalha o mecanismo para a sua fosforescência e sua identificação auxiliada pela espectroscopia de Raman e espectrofluorimetria.
Food safety experts in the European Union (EU) have recently updated their safety assessment of TiO2 as a food additive. In Europe, TiO2 is referred to as E171, in accordance with European labelling requirements for food additives. The EU expert panel took into account toxicity studies of TiO2 nanoparticles, which to this point had not been considered relevant to the safety assessment of TiO2 as a food additive.
In addition to its use as a pigment, titanium dioxide also has a wide range of other applications. For example, it is used in sunscreens to protect skin from harmful UV rays. The photocatalytic properties of titanium dioxide allow it to break down organic compounds when exposed to sunlight, making it an effective agent for environmental remediation.
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.
While this ruling from the EU General Court doesn’t immediately change the regulations surrounding titanium dioxide, nor does it change the ban that went into place in 2022, it does put the ingredient back in the spotlight.
In the coming months, we will see how the ruling impacts the regulations around titanium dioxide (E171), and we’ll see if the European Food Safety Authority (EFSA) will take another look at the body of scientific evidence used to justify the current ban on E171 in foods and pharmaceuticals.
In the coming months, we will see how the ruling impacts the regulations around titanium dioxide (E171), and we’ll see if the European Food Safety Authority (EFSA) will take another look at the body of scientific evidence used to justify the current ban on E171 in foods and pharmaceuticals.