Mercury

# What is mercury? Mercury is a heavy metal that occurs in the environment in various forms, including elemental mercury, inorganic mercury compounds and organic mercury compounds such as methylmercury. This metal is best known for its toxicity, which is important for both the environment and human health. Exposure to mercury occurs mainly through the consumption of contaminated fish and seafood, with methylmercury being considered the most dangerous form for humans. This form of mercury can accumulate in the human body and damage the central nervous system, which is particularly dangerous for pregnant women and children. The damage to the brain and nerves caused by methylmercury is irreversible and can lead to a variety of neuropsychological deficits. Mercury can also be absorbed through the skin or by inhaling vapors released during combustion or industrial processes. In the human body, mercury is distributed in various tissues and accumulates in the liver, kidneys and brain. The detoxification and excretion of mercury occurs, among other things, by binding to glutathione, an antioxidant tripeptide that plays a key role in the body in the breakdown of toxic substances. The health effects of mercury are influenced by genetic factors, in particular by polymorphisms in genes involved in the synthesis and regulation of glutathione. # Environmental dispersion Mercury enters the environment through natural and anthropogenic processes and is distributed in air, water and soil. A significant proportion of the mercury released comes from human activities such as coal burning, mining and industrial processes. Once released into the atmosphere, mercury can travel long distances before settling in the oceans or on land masses. In aquatic systems, mercury is converted by microbial processes into its organic form, methylmercury, which is highly toxic and easily accumulates in the food chain. This bioaccumulation leads to high concentrations of methylmercury in fish, especially in predatory fish, and enters the human body through the consumption of fish. > ## Did you know? > > Mercury is distributed unevenly in the human body, with the plasma concentration depending largely on the type of mercury ingested: Methylmercury accumulates in the brain, while inorganic mercury is mainly stored in the kidneys. # Toxicological effects Mercury, especially methylmercury, poses a considerable risk to human health. The substance can cross the blood-brain barrier and damage the central nervous system. The toxicological effects include neuropsychological deficits, motor disorders and cognitive impairment. Pregnant women are particularly at risk as methylmercury crosses the placental barrier and impairs the neuronal development of the fetus. Chronic exposure also leads to long-term health damage in adults, which manifests itself in memory loss, speech disorders and other neurological problems. The toxic effect of mercury is not limited to the nervous system, but can also lead to kidney and cardiovascular damage. # Preventive measures To minimize the impact of mercury on the environment and health, various regulatory measures have been introduced worldwide. The Minamata Convention, an international agreement, aims to reduce the release of mercury into the environment and restrict the use of mercury in industry. In addition, many countries have introduced national mercury pollution monitoring and control programs that set strict limits on mercury emissions. These measures help to reduce global mercury pollution and minimize risks to human health in the long term. # What does genetics have to do with it? The genetic link between mercury exposure and the body's ability to detoxify the heavy metal is closely linked to certain single nucleotide polymorphisms (SNPs) in glutathione-associated genes. The SNP rs761142 in the GCLC gene, which codes for glutamate cysteine ligase, the rate-determining enzyme component of glutathione synthesis, influences glutathione levels in the body and thus the efficiency of mercury detoxification. Variations in this SNP lead to differences in the ability to produce glutathione, which in turn affects individual blood mercury concentrations and susceptibility to mercury toxicity. The SNP rs1138272 in the GSTP1 gene codes for the enzyme glutathione S-transferase P1, which is involved in the conjugation of glutathione with toxic substances such as mercury. A change in this SNP alters the activity of the enzyme, which leads to an altered binding capacity for mercury. Individuals with certain variants of this SNP therefore have different mercury concentrations in biological tissues, as detoxification efficiency is impaired. The SNP rs366631 in the GSTM5 gene influences the function of the enzyme glutathione S-transferase Mu 5, which is also involved in the detoxification of mercury. Polymorphisms in this gene are associated with altered expression of the enzyme, which in turn affects the body's ability to convert mercury into less toxic forms and excrete it.