Metabolism (see fig. 1)
The most dangerous characteristic of cadmium is that it accumulates throughout lifetime. Cadmium accumulates in the liver and kidneys and has a long biological half-life, from 17-30 years in man (Goyer, 1997). After uptake from the lung or the gastrointestinal tract, cadmium is transported in blood plasma initially bound to albumin, as shown in experimental animals. Cadmium bound to albumin is preferentially taken up by the liver. In the liver, cadmium induces the synthesis of metallothionein and a few days after exposure metallothionein-bound cadmium appears in the blood plasma. Because of its low molecular weight, cadmium-metallothionein is efficiently filtered through the glomeruli and thereafter taken up by the tubules. Cadmium accumulates in the human kidney over the entire lifetime (Nordberg, 1992).