Cadmium: A toxic metal

Uses of Cadmium

Toxic metals are "metals that form poisonous soluble compounds and have no biological role" (wikipedia). Cadmium is one of these metals. It was discovered in 1817 by two scientists as an impurity of zinc carbonate. They eventually isolated the metal by roasting and reduction of the sulfide.
 Cadmium is considered rare and only makes up .1 parts per notation of the earth's crust. Cadmium is used in the production of batteries and is commonly used in electroplating. Cadmium is used mostly in rechargeable nickel-cadmium batteries and is used in electroplating for aircrafts because it resists corrosion. 

Cadmium Battery

Cadmium has no use for most organisms, other than marine diatoms. Cadmium is only used by organisms in environments with low zinc concentrations because Cadmium can perform it's functions.  Cadmium is toxic to humans and most exposure comes from inhalation of fumes during production of materials containing cadmium. Humans are exposed to Cadmium in the environment during iron and steel production and fossil fuel combustion. 

Ingredients in a cigarette

Tobacco smoking is the most important source of Cadmium exposure in humans. Smokers have 4-5 times higher Cadmium concentrations in their blood than non-smokers. Side effects of high Cadmium levels in the body include loss of sense of smell, renal failure, irreversible kidney damage, softening of bones, and breathing problems. 

As far as toxicity goes, inhalation levels should not be higher than .0002 milligrams of cadmium per cubic meter of air. Levels above 0.0035 mg/m3 increase the chance of lung and kidney injury.

Moral of the story? Stay away from Cadmium!