Lead (symbol Pb) belongs to the group of heavy metals and is an element known and used since the dawn of human civilization (exploited for at least 8000 years). It is not an essential nutritional element and is toxic to humans.
Nowadays it continues to be used in a wide range of industries, such as: munition, explosives, batteries, chemical industry or ceramics. Spreading Pb in nature and its varied uses made it a widespread toxic.
In the last 50 years, Pb and pollution with this metal have increased dramatically, as it is shown in successive structures of Greenland glaciers.
Thus, in the layers corresponding to the industrial revolution (1780) 1g of ice contains 10µg Pb.
Two hundred years later, the concentration of Pb per 1g of ice is 20 times higher (200μg). It is estimated that in the US 1.3 million tons of this metal are being used, releasing about 100,000 tons of Pb in air and water.
There is no known physiological function of Pb in the body. People accumulate it in their tissues and the highest concentration is found in the urban population.
This accumulation is directly correlated with industrialization and the use of leaded petrol. Other sources are: some cosmetics and traditional medicines, certain foods, especially glazed sweets, paints that are still commonly used for interior decoration.
It can enter the drinking water through the corrosion of pipes. This is more likely to happen when the water is slightly acidic.
For this reason, lately, public water treatment systems make pH adjustments. The maximum permissible limit for Pb in drinking water is 0.01 ppm.
There is a daily intake of 100-300μg Pb in our body, through food, contaminated air, water, etc., reaching a level of 200mg of Pb, a constant amount found in an adult body.
These amounts oscillate between 100-500mg of Pb, depending on its levels found in the environment. In the lead-processing industry, a worker can absorb up to 400μg of Pb during 8 hours (plus the 200-300μg absorbed through food, water or ambient air).
The lungs absorb 50-70% of the inhaled dose. Gastrointestinal absorption of Pb is 5-10% in adults and up to 40% in children. The skin can absorb only organic compounds (tetraethyl Pb) in amounts sufficient to generate systemic toxicity.
Distribution of this heavy metal in the body is done tricompartmental: blood compartment, bone, and soft tissue. In the blood, 95% of it is found in the red blood cells with a half-life period of 35 days. Bones are the main repository of lead in the body, up to 90% of the Pb quantity.
The half-life period of Pb in the bones is 20-30 years. About 10% of Pb in the body releases in the soft tissues with a half-life period of 40 days. Thus, blood Pb levels do not reflect the total amount of Pb in the body.
Depositing and elimination of Pb from the bones are done in-line with similar calcium process. A diet that is low in calcium, phosphate, selenium, and zinc can favor an increased Pb absorption.
Also, iron and vitamin D influence the absorption and elimination of Pb. Elimination is done by kidneys through filtration and tubular secretion, representing the main way of excretion (75%). Secondary routes are phanaers, sweat, and digestive track. It passes through the placenta and affects the fetus and it is also found in the milk secretion, affecting infants.
What are the side effects of lead poisoning?
Effects of Pb on organs and body systems have been extensively studied over time, so that people can now be aware of its effects on the nervous, cardiovascular, renal and reproductive system. One of the most important is blocking the synthesis of heme, decreasing hemoglobin levels and anemia.
Chronic effects: anemia, neurological disorders, low immunity. Also, it affects kidney function, blood pressure, normal evolution of pregnancy.
Effects on reproduction: The presence of Pb in the body affects male fertility, according to recent research. The high concentration of Pb can cause sterility because it affects sperm motility.
In women, Pb exposure affects the libido and increases the risk of miscarriage, premature birth or even miscarriage. It enters the placenta and accumulates in the embryo’s tissues, including the brain and can permanently injure the child. It may also cause delayed growth, learning disabilities, hearing problems, low memory or aggressiveness.
Effects on vision: research has shown that Pb exposure increases the risk of developing cataracts.
The risk of cancer: increases the risk of cancer, particularly the stomach, lungs, and bladder.
1.People with calcium and iron deficiency
Numerous studies have shown that certain deficiencies in minerals, such as calcium, iron and zinc, contribute to the increase of Pb absorbed.
During the growing process, they absorb and retain substances, including Pb, much easier. Also, having a lower bone mass, lead accumulates in soft tissues. Due to the fact that development is not finished yet, their organs become more involved in this process, and not the removal of Pb.
Numerous studies have also indicated that the nervous system is very sensitive to Pb, especially in the first 3 years of life. As a result, the repercussions that can occur in children are: loss of appetite, anemia, abdominal pain, constipation, weight loss, fatigue, insomnia, irritability, headaches, mental retardation, slow growth.
The reason is these women often begin to develop osteoporosis, which is a serious and progressive loss of bone mass. This way, Pb accumulated in the bones will again be released into the blood.
What can you do?
- Use lead-free paint for the walls.
- Make sure the furniture does not contain Pb.
- Don’t let children play in places where there are old walls or objects.
- Don’t use dishes, pots, pans if you are not sure whether they contain Pb or not.
- Before using tap water, leave it running more. Replace old pipes, install filters, change the Pb installations.
- Wash all vegetables and fruits with cold water at high pressure.
- Don’t keep food in open places where they are in contact with dust particles.
- Avoid consuming canned products because they have a high content of Pb.
Antioxidants reduce the toxic effects of Pb. A study conducted by researchers at the University of Madrid established that administration of natural antioxidants reduces the harmful effects of Pb.