Lead poisoning is a serious condition that can endanger health and sometimes it can be even fatal. Lead poisoning can be divided into acute poisoning (sudden and high increase of lead concentration in the body) and chronic poisoning (long-term slightly elevated concentrations of lead in the body). Particularly the chronic poisoning is very interesting for the European population as our ancestors unknowingly came into close and harmful contact with lead products in their everyday life.
Lead is a solid and stable metal that is resistant to corrosion. For this reason, the lead has been used throughout the history. In ancient Rome and in the Middle Ages, lead served as the material for production of large containers and for construction of water pipes. Later, the lead has been also used in paints and in industry. Due to the widespread use of lead it is clear that people received certain doses of lead in food and water. In particular, many citizens of the ancient Rome suffered from chronic lead poisoning because of lead-made water pipes and lead dishes. The lead, however, may not be received only in food, but also in the form of gases and dust containing this element.
As I wrote above, we can distinguish between lead poisoning to acute and chronic.
Acute poisoning by lead has very dramatic manifestations. The victim suffers from acute colicky abdominal pain (“lead colic, or Saturnine colic”), vomiting, diarrhea, muscle cramps and sometimes even unconsciousness. Acute intoxication with a very high doses lead may be fatal.
The symptoms of chronically increased intake of lead are subtle and vague. The affected person may feel tired; he or she experiences lethargy, loss of appetite and occasional nausea. The skin of people exposed to lead may gradually obtain grayish color and a gray-blue rim may occur on the gums. Mental functions may be impaired including low ability to concentrate, memory problems, reduced intelligence, etc. Anemia often develops in the affected person. Long-term lead poisoning can cause chronic kidney failure.
In children, lead can interfere with proper psychomotor development and cause behavioral and learning disorders. If the lead comes to a close contact with a fetus, it can cause intrauterine disorders, miscarriages or premature births.
The problem is that the lead tends to accumulate in the body and it is not easy to get rid of it. Once it enters our body, it is stored in teeth and bones. Out of there, it is gradually released into the blood and slowly excreted through kidneys into the urine and by liver into the bile.
When there is a suspicion of a lead poisoning, we can try to measure the lead concentration in the blood. However, lead poisoning may be also visible when examining the erythrocytes under the microscope as they are stained with dark-bluish dots. In chronic poisoning, the majority of lead is stored in the bones and its serum concentration may therefore not accurately testify about the total amount of lead in the body.
It is important to determine the source of lead poisoning and prevent further contact with it. Special chelating agents may be used to reduce the amount of lead in the blood. Chelating agents are substances that are able to bind the metallic molecules (in this case the lead) and increase their elimination out of the body. Such chelating agent is for example the EDTA (ethylenediaminetetraacetic acid).