Why is methylmercury so toxic?
Methylmercury is the most toxic among the mercury species because of its volatility and its ability to pass through biological membranes such as the BBB and the placental barrier. The nervous system and kidneys are the two major target organs.
What is the mechanism of toxicity of mercury?
Mechanism of Toxicity Mercury ions produce toxic effects by protein precipitation, enzyme inhibition, and generalized corrosive action. Mercury not only binds to sulfhydryl groups but also to phosphoryl, carboxyl, amide, and amine groups.
How does methylmercury affect the body?
The primary health effect of methylmercury is impaired neurological development. Therefore, cognitive thinking, memory, attention, language, and fine motor and visual spatial skills may be affected in children who were exposed to methylmercury as foetuses.
How is methylmercury metabolized?
In humans, the major routes of excretion are via the bile and feces. About 90% of a given dose of MeHg is eventually excreted in the feces as mercuric Hg in humans and other species. Approximately 10% is excreted as mercuric Hg via the urine.
What is methylmercury toxicity?
Methylmercury is a very poisonous form of mercury. It forms when bacteria react with mercury in water, soil, or plants. It was used to preserve grain fed to animals. Methylmercury poisoning has occurred in people who have eaten meat from animals that ate grain that was treated with this form of mercury.
Why is methylmercury important?
The toxic effects of mercury depend on its chemical form and the route of exposure. Methylmercury [CH3Hg] is the most toxic form. It affects the immune system, alters genetic and enzyme systems, and damages the nervous system, including coordination and the senses of touch, taste, and sight.
Is methylmercury organic?
Microscopic organisms in water and soil can convert elemental and inorganic mercury into an organic mercury compound, methylmercury, which accumulates in the food chain. Thimerosal and phenylmercuric acetate are other types of organic mercury compounds made in small amounts for use as preservatives.
What is the mechanism of action of lead poisoning?
The major mechanism of lead toxicity is due to increased generation of reactive oxygen species (ROS) and interference with generation of antioxidants. Lead causes the generation of ROS like hydroperoxide, hydrogen peroxide, and singlet oxygen. ROS are stabilized by glutathione in the body.
What is dimethylmercury used for?
For example, a major use of dimethylmercury is to calibrate certain research equipment such as Nuclear Magnetic Resonance (NMR). Inorganic mercury salts reportedly can be substituted for most of these operations.
Where does methylmercury accumulate in the body?
It crosses the blood-brain barrier and accumulates in the brain, where it can damage the central nervous system. About 10% of the MeHg in the body is in the brain; there, it is slowly demethylated to inorganic mercury, which crosses the blood-brain barrier very poorly.
What steps are involved in toxicokinetics?
Toxicokinetics refers to the movement and fate, also referred to as the disposition, of toxicants. It includes the processes of absorption, distribution, and elimination (including biotransformation and excretion) of toxicants in an organism.
What is methylmercury used for?
Methylmercury is used in fluorescent lights, batteries, and polyvinyl chloride. It is a common pollutant of air and water.
How is methylmercury harmful to the human body?
Characteristics of Methylmercury. People can be exposed to mercury through air, food, drink, and amalgam-treated teeth. From mercury flowing into the human body, methylmercury is known to have the strongest toxicity to humans, showing a high rate of human residues, such as 95% in one study [ 6 ].
What are the health effects of mercury exposure?
Cardiovascular effects. The NRC concluded that mercury exposure would have effects on cardiovascular diseases, reporting that methylmercury’s toxic effects include increased blood pressure as it was accumulated in heart, and noting that in mercury poisoning incidents, abnormal heartbeats, abnormal electrocardiogram,…
Where does Mercury go when exposed to methylmercury?
Distribution. It is known that when people are exposed to methylmercury, blood mercury moves to the follicle in the hair growth stage and is accumulated there. It has also been shown that the mercury concentration in hair is proportional to the blood concentration [ 12 ].
Which is the most toxic form of mercury in the air?
From mercury flowing into the human body, methylmercury is known to have the strongest toxicity to humans, showing a high rate of human residues, such as 95% in one study [ 6 ]. The concentration of total mercury in the air is known to be <10 ng/m 3, 22% of which is monomethylmercury and dimethylmercury.