Toxicity platinum group metals

Relative Toxicity of the Platinum Group Metals to the Water Hyacinth (Eiohhomia orassipes)... 

Control of residual metal content is outlined in ICH Q3D. It is noteworthy that the metals currently most useful for chemical catalysis (Green Chemistry Principle 9), e.g. palladium and some platinum group metals (Rh, Ru, Ir), are subject to tight restriction because of known toxicity, or the assumption of near neighbour similarity in the absence of data. All four metals have an oral concentration limit of 10 ppm, reducing to 1 ppm via parenteral administration and 0.1 ppm via inhalation. Typically, delivery of API with low residual metal content can require additional processing and careful analysis to determine levels. Some of the more abundant metals suggested... 

Antiproliferative non-platinum-group metal antitumor agents are generally characterized by spectra of activity against experimental animal tumors which are different from the antitumor spectrum of cytostatic platinum complexes Moreover, the toxic properties and the cellular mode of action at least of some of the non-platinum complexes fundamentally deviate from that shown for antitumor platinum compounds 1. 

However, the present discussion will be prevalently addressed to toxic metals with great attention to metals of particular interest, at least at the present time, like for example Platinum Group Metals (PGMs), mercury(II) and heavy metals [Cu(II), Pb(II), Cd(II) and Zn(II)]. 

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. 

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... 

Like the ammonia synthesis, catalytic oxidation of carbon monoxide is at the core of a major technological process, namely the removal of toxic substances from automobile exhaust. In a catalytic converter, the exhaust fumes interact with the surface of fine-grained particles of metals from the platinum group. While the carbon monoxide (CO) molecules are adsorbed by the surface of the catalyst, the oxygen molecules (O2) contained in the fumes are dissociatively chemisorbed. 

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