Vanadium alloys toxicity

Vanadium compounds, including those which may be involved in the production, processing, and use of vanadium and vanadium alloys, are irritants chiefly to the conjuctivae and respiratory tract. Prolonged exposure may lead to pulmonary compHcations. However, responses are acute, never chronic. Toxic effects vary with the vanadium compound involved. For example, LD q (oral) of vanadium pentoxide dust in rats is 23 mg/kg of body weight (24). 

The toxicity of vanadium alloys may depend on other components in the alloy. For example, the V Ga alloy requires precautions related to both vanadium and gaUium, and gallium is highly toxic. Similarly, alloys with chromium may require precautions associated with that metal. 

The a—and P-aHoys are used where higher strengths are required, such as in shafts, oil and gas weUs, and medical implants. Again, Pd and Ru variations of the basic alloys are available where improved corrosion resistance is needed. Several of the Hsted P-aHoys were developed for implants. These alloys were designed to be free of aluminum and vanadium, which have created some concern related to potential toxicity when used in implants (50). 

Diamond-like carbon can be alloyed with toxic materials. This is necessary when no cell adhesion should be allowed specifically when equipments or implants are of temporary use. When this alloy makes contact with the biological environment, the cytotoxic materials, like copper, vanadium, and silver, inhibit cell growth on the material surface because of the toxic action of the alloy. Changing alloy components can control the bioreactions. When DLC is mixed with silicon oxide a reduction of the inflammatory reactions is observed. 

Typically, titanium alloys have been the materials of choice for medical implants. The Ti-6A1-4V alloy is generally considered chemically inert, compatible with human tissue, and resistant to corrosion by human body fluids. However, the small percentages of vanadium and aluminum contained in the alloy are potentially toxic. Pure titanium is chemically and biologically more compatible with human fluids and tissue, but it is too weak for prostheses that must bear heavy loads, such as leg or hipbone implants. 

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