ABSTRACT

Lanthanides (LAs), often called rare earth elements, comprise 15 elements, of which only one, promethium, does not occur naturally in the Earth’s crust. Organic compounds play a significant role in the distribution of LAs and affect their increased levels in humus horizons of soils and in forest soil litter. The mobility of LAs in soils is variable and controlled by both soil pH and climatic factors. The concentration of LAs in food plants is of a special concern. LA amounts in vegetable are very variable, apparently due to their various contents in soils. LAs have no known biological role in living organisms, but they are present in human bones, and to a lesser extent, in the liver and kidneys. The chemical forms of LA compounds determine deposition and retention of LAs, following different ways of exposure. LAs entering the human body, due to exposure to various industrial works, can affect metabolic processes.