Uranium (U) in blood.

Many inorganic ions can be identified in the human body. Some of them are absolutely essential elements for normal metabolism, such as sodium, potassium, zinc, selenium and iodine. Others (mercury, cadmium, lead) do not fulfil any function and even, on the contrary, have toxic effects when accumulated in high concentrations. To diagnose acute or chronic intoxication of the body, analyses for the presence of a particular trace element are used.  The toxicity of inorganic ions depends on many factors, including age, sex, physiological state of the organism, presence of concomitant diseases, as well as route of entry into the body and dose. The main sources of heavy metals and trace elements are food and water, inhaled air and, in some cases, medicines.  The most frequent cases of trace element poisoning are registered at work. Although the clinical picture of heavy metal and trace element poisoning differs somewhat depending on the nature and chemical structure of the substance, it is not possible to identify the element that caused the diseases on the basis of clinical signs alone.