Methyl Mercury

Mercury is persistent, mobile and bioaccumulative in the environment, meaning it is retained in organisms. Most of the mercury found in the environment is inorganic mercury that can enter the air from several sources. Examples of sources include emissions of burning municipal and medical waste containing mercury, and natural processes such as erosion of ores and volcanic activity.

Methyl mercury is quickly taken up into higher organisms through the food chain and is retained in their bodies. It reaches the highest levels in large predatory fish and in birds and mammals which consume fish. Levels of methyl mercury in fish are typically 100,000 times those in the water in which they swim. Methyl mercury is formed from the addition of a methyl group and appears to be more toxic to higher animals than inorganic mercury (Dietz et al., 1990). Organic mercury is a conservative pollutant and biomagnifes in the food chain (e.g., in ringed seals; Dietz et al., 1990), posing a potential hazard to organisms of higher trophic levels.

Poisoning may result from inhalation of the vapor, absorption of mercury through the skin, or ingestion of soluble compounds. Typically inorganic mercury accumulates in the liver, while methyl mercury accumulates in muscle tissue (Sadiq, 1992).

Damages to the body

Damages the stomach and large intestine
Permanently damages the brain and kidneys
Permanently harms unborn children
Can cause lung damage, increased blood pressure and heart rate
May cause cancer

How Does Mercury Affect the Nervous System?

Methyl mercury targets and kills neurons in specific areas of the nervous system including the Visual cortex, Cerebellum and Dorsal root ganglia.

Several mechanisms have been proposed to explain how mercury kills neurons:

Protein inhibition
Disruption of mitochondria function
Direct affect on ion exchange in a neuron
Disruption of neurotransmitters
Destruction of the structural framework of neurons

Methylmercury is especially dangerous to developing babies. This form of mercury is highly toxic and can cross the placenta and the blood-brain barrier. Mercury is concentrated in the brain of the developing fetus because the metal is absorbed quickly and is not excreted efficiently. Children exposed to mercury may be born with symptoms resembling cerebral palsy, spasticity and other movement abnormalities, convulsions, visual problems and abnormal reflexes. The brains of children who have died as a result of mercury poisoning show neuron loss in the cerebellum and throughout the cerebral cortex. Mercury also appears to affect brain development by preventing neurons from finding their appropriate place in the brain.