Rubidium food chain

Rubidium typically exists in the human body at the level of only 1/1,000 of 1 percent, and cesium content is even lower. Rubidium and cesium are both absorbed from soil by plants and are, therefore, present in small quantities in vegetables and up the food chain to meat products and humans. Rubidium is known to stimulate mammalian metabolism, probably because of its physical and chemical similarity to potassium, which plays a crucial role in electrical pulse transmission along nerve fibers protein synthesis acid-base balance and formation of collagen, elastin, and muscle. Its likeness to potassium may be the reason rubidium enhances growth in some plants. For particular insects, however, the introduction in the laboratory of rubidium to the bloodstream has been shown to drastically reduce fluid secretion and to change the electric potential across cell membranes. Excess rubidium is almost never encountered, however, in nature. 

Anke M and Angelow L (1995) Rubidium in the food chain. Eresenius J Anal Chem 352 236-239. 

Anke M, Angelow L, Glei M, Muller M, Gunstheimer U, Rohrig B, Rother C and Schmidt P (1997a) Rubidium in the food chain of humans Origins and intakes. In Eischer PWE, U Abbe MR, Cockell KA and Gibson RS, eds. Trace Elements in Man and Animals-9. NRC Research Press,... 

The transfer of rubidium in the food chain from flora to fauna is without problems, as it was shown to occur in two species of herbivorous mice. On average, mice and voles accumulated 9 mg, and carnivores 5 rag Rbkg DM. The difference between both groups was highly significant and showed the different rubidium intake (Anke et al. 1997). 

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