Metal toxicity platinum

Ruehle T, Schneider H, Find J, Herein D, Pfaender N, Wild U, Schloegl R, Nachtigall D, Artelt S, Heinrich U (1997) Preparation and characterisation of Pt/A1203 aerosol precursors as model Pt-emissions from catalytic converters. Appl Catal B Environ 14 69-84 Schafer J, Hannker D, EckWdt JD, Stiiben D (1998) Uptake of traffic-related heavy metals and platinum group elements PGE by plants. Sci Total Environ 215 59-67 Speranza A, Leopold K, Maier M, Taddei AR, Scoccianti V (2009) Pd-nanoparticles cause Increased toxicity to kiwifruit pollen compared to soluble Pd. Environ Pollut (submitted) Sures B, Zimmermann S (2007) Impact of humic substances on the aqueous solubility, uptake and bioaccumulation of platinum, palladium and rhodium in exposure studies with Dreissena polymorpha. Environ Pollut 146(2) 444 51... 

The complexes of substitutionally inert metal ions should be carefully investigated for their anti-tumor activity because they may present superior alternatives to the toxic platinum(II) compounds. 

The release of VOCs into the environment has widespread environmental imph-cations. Pollution by VOCs has been linked to the increase in photochemical smog and ozone depletion. In addition, many VOCs are themselves toxic and/or carcinogenic. The US Clean Air Act of 1990 was one of the first measures to call for a 90% reduction in the emissions of 189 toxic chemicals, with 70% of these classed as VOCs, by 1998. Hence, in recent years, the development of effective technologies for the removal of VOCs from the atmosphere has increased in importance with the introduction of legislation to control their release. Various methods have been proposed, and one of the best is heterogeneous catalytic oxidation. This has the advantage over the more common original thermal oxidation process, since it requires less supplementary fuel and is therefore a less expensive process. However, the characteristics of the catalyst selected for this process are of vital importance for successful operation, and potential problems such as lifetime and deactivation must be solved if catalytic oxidation is to be employed universally. Catalysts currently in use include noble metals, notably platinum and palladium, and those based on metal oxides, however, irrespective of the type of catalyst, the most important characteristics are activity and selectivity for total oxidation. 

The noble metals, including platinum Pt, gold Au, iridium Ir, palladium Pd, and rhodium Rh, have been commonly used for electrical stimulation, largely due to their relative resistance to corrosion [28, 51, 52]. These noble metals do exhibit some corrosion during electrical stimulation, as shown by dissolution [53, 54, 55, 56, 57] and the presence of metal in the neighboring tissue [58, 59]. In addition to corrosion of the electrode, there is evidence of long-term toxic effects on the tissue from dissolution [60, 61, 62],... 

Some metals used as metallic coatings are considered nontoxic, such as aluminum, magnesium, iron, tin, indium, molybdenum, tungsten, titanium, tantalum, niobium, bismuth, and the precious metals such as gold, platinum, rhodium, and palladium. However, some of the most important poUutants are metallic contaminants of these metals. Metals that can be bioconcentrated to harmful levels, especially in predators at the top of the food chain, such as mercury, cadmium, and lead are especially problematic. Other metals such as silver, copper, nickel, zinc, and chromium in the hexavalent oxidation state are highly toxic to aquatic Hfe (37,57—60). 

The most successful class of active ingredient for both oxidation and reduction is that of the noble metals silver, gold, ruthenium, rhodium, palladium, osmium, iridium, and platinum. Platinum and palladium readily oxidize carbon monoxide, all the hydrocarbons except methane, and the partially oxygenated organic compounds such as aldehydes and alcohols. Under reducing conditions, platinum can convert NO to N2 and to NH3. Platinum and palladium are used in small quantities as promoters for less active base metal oxide catalysts. Platinum is also a candidate for simultaneous oxidation and reduction when the oxidant/re-ductant ratio is within 1% of stoichiometry. The other four elements of the platinum family are in short supply. Ruthenium produces the least NH3 concentration in NO reduction in comparison with other catalysts, but it forms volatile toxic oxides. 

Peroxides are very toxic to the cornea of the eye. After the disinfection cycle, and before placing the lens in the eye, hydrogen peroxide must be completely neutralized by reducing agents, catalase, or transition metals, such as platinum. 

Inorganic or metal-containing medicinal compounds may contain either (a) chemical elements essential to life forms—iron salts used in the treatment of anemia—or (b) nonessential/toxic elements that carry out specific medicinal purposes—platinum-containing compounds as antitumor agents or technetium... 

The observed trends in toxicities of the three characteristic aromatic series 1, 2, 3 may be explained by the factors governing n complex adsorption. It is important to realize that in toxicity studies the metal orbital factor in tt complex adsorption is held constant by confining investigations exclusively to platinum catalysts. 

The elemental metal form of iridium is almost completely inert and does not oxidize at room temperatures. But, as with several of the other metals in the platinum group, several of iridiums compounds are toxic. The dust and powder should not be inhaled or ingested. 

Fine platinum powder may explode if near an open flame. Because platinum is rather inert in its elemental metallic form, it is not poisonous to humans, but some of its compounds, particularly its soluble salts, are toxic if inhaled or ingested. 

Platinum is a relatively rare earth metal usually found with related metals osmium and iridium. While it has a number of industrial applications, its common consumer application is in catalytic converters. This application has actually increased platinum concentrations in roadside dust. The ability of platinum and its derivatives to kill cells or inhibit cell division was discovered in 1965. Platinum-based drugs, such as cisplatin, are used to treat ovarian and testicular cancer, and cancers of the head and neck, as well as others. Unfortunately, the toxic side effects of these agents often limit their usefulness. 

Listed as asphyxiants are the much more inert gases of argon, helium, hydrogen, neon, and nitrogen. Many elements are missing from this table, either because they are harmless or because they have not been measured. The values listed in table 6.6 are for the elements, but some of them have compounds that are much more toxic than the parent element. For instance, platinum metal is toxic at 1 mg/m, but soluble plahnum salts are toxic at 0.002 mg/m. ... 

---