Proceedings Of The Marine

SPR 2014

Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.

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Health concerns High concentrations of titanium dioxide dust may cause coughing, and mild, temporary irritation. Long-term inhalation of high concentrations of powdered or ultraf ne titanium dioxide may cause lung cancer, based on labora- tory studies. In general, long-term exposures to high con- centrations of dust may cause increased mucous f ow in the nose and respiratory system. However, this condition usually disappears after exposure stops. Controversy exists as to the role occupational exposure to dust has in the development of chronic bronchitis (inf am- mation of the air passages into the lungs). Other factors such as smoking and general air pollution are also impor- tant, but dust exposure may contribute to this effect. In lab- oratory studies, long-term inhalation exposure has caused persistent adverse effects on the lungs (e.g. inf ammation, f brosis, changes to alveolar cells), which are believed to result from dust overloading of the lungs. Effects with ultraf ne titanium dioxide occur at much lower exposure concentrations than are required with the larger sized pig- ment-grade particles. The effects are more closely related to lung burden in terms of the surface area rather than the mass of the particles. Fire or explosion concerns Titanium dioxide does not burn and does not support combustion. What is the Coast Guard doing about it? Titanium dioxide is categorized as a "Subchapter O" cargo regulated in 46 Code of Federal Regulations Parts 150 and 153. If this cargo is carried in domestic tank barges, it is not regulated, since it does not burn and does not have safety hazards. If carried on ships, the vessel masters must follow the IBC codes, and the Coast Guard must inspect the vessels. About the author: Ms. Roshanak Aryan-Nejad is a chemical engineer working in the Sys- tems Engineering Division at U.S. Coast Guard headquarters, focusing on domestic and international regulations. Her background is in environ- mental engineering and regulatory compliance. What is it? Titanium dioxide (TiO 2 ), also known as titania, is the natu- rally occurring oxide of titanium and is the most widely used white pigment, because of its brightness and very high refractive index. It is a substitute for lead paint and is in 70 percent of pigments worldwide. Titanium diox- ide is also used as a pigment to provide whiteness and opacity to products such as paints, plastics, papers, foods, beverages, medicines, and cosmetics like sunscreen. It is popular for sunscreen, because of its high refractive index, its strong ultraviolet (UV) light absorbing capabilities, and its resistance to discoloration under UV light. Titanium dioxide can also produce electricity, when trans- parent, and under the inf uence of light in its nanoparticle form. However when subjected to electricity, the nanopar- ticles blacken and form the basic characteristics of a LCD screen. Titanium dioxide also offers great potential as an industrial technology for detoxif cation or remediation of wastewater due to the following factors: • The process uses natural oxygen, sunlight, and thus occurs under ambient conditions; it is wavelength selective and accelerated by UV light. • The photo catalyst is inexpensive, readily available, non-toxic, chemically and mechanically stable, and has a high turnover. • Oxidation of the substrates to CO 2 is complete. • TiO 2 can be supported on suitable reactor substrates. How is it shipped? TiO 2 is an odorless gray powder, which is insoluble in water. It is shipped in bulk tank vessels as a slurry, since it is a solid. Why should I care? Shipping concerns Titanium dioxide slurry is categorized as a Category Z in the International Code for the Construction and Equip- ment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code), 2007 Edition. Being a Category Z effectively means that it is deemed to present a minor hazard to marine resources or human health. Understanding Titanium Dioxide by Ms. roshAnAK AryAn-nejAD Chemical Engineer U.S. Coast Guard Headquarters Systems Engineering Division 62 Proceedings Spring 2014 www.uscg.mil/proceedings Chemical of the Quarter Spring2014_FINAL.indd 62 3/21/14 11:14 AM

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