Definition
Mercury is a heavy metal toxic to the body. Especially the evaporation of metallic mercury, which already starts at room temperature, produces highly toxic vapors that are absorbed through respiration and spread throughout the body. In recent decades, the use of mercury in medical products has been increasingly reduced and in some cases even banned. Nevertheless, considerable amounts of mercury are still found, especially in older products, which can cause severe damage to the human body both in acute and chronic exposure.
Causes
The causes of mercury poisoning are manifold. Mercury is used, among other things, in older thermometers (used regularly until the 1970/80s) and in energy-saving lamps. Breaking the glass and releasing the mercury content can lead to the absorption of toxic mercury gases into the body.
In addition, large amounts of mercury gases are produced during the combustion of coal, extraction of natural gas and the manufacture of various industrial products. Last but not least, mercury was also used for medical products. As an additive in liquid vaccines (thiomersal), it served as a preservative for years until it was increasingly banned since the 2000s.
As an ingredient of amalgam, it is used to fill dental fillings. The long-term effect of these amalgam fillings on humans is highly controversial. The regular and heavy consumption of fish can also trigger mercury poisoning in individual cases.
These absorb the organic mercury residues via the water and form highly toxic decomposition products (methyl mercury). In the last centuries mercury was used for temperature measurement in clinical thermometers. The temperature-dependent expansion of mercury is used for this purpose.
There is about 1 gram of mercury in a clinical thermometer. If the glass of the clinical thermometer is broken, there is a risk of releasing the mercury, which already evaporates in small doses at room temperature to highly toxic vapors. Investigations and studies have shown, however, that these doses are so small that there is no danger to the patient through inhalation.
For safety reasons, the sale of thermometers containing mercury was banned in the European Union in 2009. Instead, thermometers that work with alcohol are increasingly being used. Amalgam is a loose compound of several heavy metals.
Besides mercury (50% of the content) it contains silver, tin and copper. Although the effect of the mercury in amalgam on the human body is controversial, it is used for dental fillings (seals) in dentistry. Research has shown that amalgam slowly dissolves over the years.
After 10 years, only about 50% of the mercury in the seal is left. However, the effect of the mercury released and evaporated at body temperature is controversial and the subject of numerous other investigations. So far, no danger of poisoning by the mercury could be proven.
For safety reasons, the use of amalgam fillings in children, adolescents, women of childbearing age and patients with kidney disease has been prohibited since 1995. Frequently used alternative fillings (composite, ormocere) have a much shorter shelf life compared to amalgam and have to be changed more often. A large part of the energy-saving lamps used today contain mercury.
If the lamp breaks and the mercury is released, there is a risk of highly toxic mercury gases being formed. However, as the quantities are small, there is no danger to humans from a single inhalation of these vapours. For safety reasons, small children and animals should be removed from the vicinity of the mercury source, as this spreads mainly in the area of the ground and these have an increased risk of poisoning.
The disposal of the mercury quantities should be carried out with specially designed aspirators. If necessary, the quantities can also first be swept into an airtight sealed glass. In addition, extensive ventilation must be ensured.
In several investigations, increased mercury quantities were detected in tuna fish. However, none of these investigations exceeded the EU limit value, above which there is a danger to humans when consumed.Tuna fish absorb the organic mercury through the water. Small amounts of mercury are released into the rivers and oceans via the wastewater of various factories.
In the body of the tuna, intermediate products of mercury are formed that are very toxic to humans. For safety reasons, the consumption of tuna during pregnancy and lactation should be avoided, as the mercury can spread into the embryo‘s body via the placenta, among other things. For decades, the mercury-containing preservative thiomersal was also used for liquid vaccines. According to numerous studies, however, no connection could be established between the vaccines and the possible occurrence of (neurological) symptoms. However, since a possible damage cannot be excluded, the mercury-containing substances have been removed from the vaccines since the 2000s.
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