Lanthanum (138,9 a.m.u.) – rare-earth element deposing in very low concentrations in several organs (spleen, dentine, tooth enamel). Vital dose is not proven, but lanthanum like other metals of this group increases phagocyte activity of leucocytes. In industry it is used in household and technical optics, laser machines, nuclear energetics, catalyst oil refinery, electronic industry, pigments manufacturing. Radioactive lanthanum isotopes are present in radioactive rain (containing in side-products of uranium, thorium and plutonium fission).
In medicine lanthanum carbonate is being used as phosphate-linking agent (Fosrenol) for treatment of patients with terminal stage of kidney disease together with hyperphosphatemia and kidney osteodystrophy. Speed of absorption in gastro-intestinal tract is very low because of development of hardly-soluble compounds, mainly phosphates. Main organs of lanthanum deposition are – bone tissue and liver. There is data about toxic effect of lanthanum on liver. The main way of excretion – bilis. All the lanthanum compounds are considered toxic.
Lanthanum and other lanthanide elements are able to compete with essential elements – calcium, magnesium, manganese, cobalt, cuprum, zinc in various biochemical processes. Toxic effects of lanthanum could be mostly caused by its effect on phosphates metabolism. Lanthanum level in hair correlates with its concentration in environment.
